Engineering › Electrical and Electronic Engineering

Electromagnetic Compatibility and Measurements

Works Count: 29315

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Description

This cluster of papers focuses on the use of reverberation chambers in electromagnetic testing, particularly for antenna measurements, near-field scanning, MIMO systems, electromagnetic shielding, source reconstruction, mode-stirred chambers, EMI testing, far-field transformation, and wireless device testing.

Keywords

Reverberation Chambers; Antenna Measurement; Near-Field Scanning; MIMO Systems; Electromagnetic Shielding; Source Reconstruction; Mode-Stirred Chambers; EMI Testing; Far-Field Transformation; Wireless Device Testing

Spherical Near-field Antenna Measurements

1988-01-01

Jan Erik Hansen

Accurate determination of the antenna characteristics is one of the key subjects where different methods have been developed for this purpose.When advantages and facilities of these methods are considered, near … Accurate determination of the antenna characteristics is one of the key subjects where different methods have been developed for this purpose.When advantages and facilities of these methods are considered, near field measurements have come forward especially in recent years.In this thesis, one of these methods which is referred to as spherical near field measurement method, has been studied.First, wave expansion in the spherical coordinates is introduced.This enables expressing the field as summation of modes which are composed of vector wave functions and coefficients of these functions.It is shown that by obtaining coefficients for measurement distance, field can be obtained at any other distance with these coefficients.However, test setup of an antenna is composed of receiver and transmitter such that one of them is antenna under test and other is measurement antenna which is usually called the probe.Hence, probe effects on the measurement must also be included for accurate results.Initially, Lorentz's Reciprocity Theorem had been used for this purpose.Then scattering matrix theory has been more commonly used.In this thesis study, scattering matrix theory is explained and generation of transmission formula with the probe compensation is presented.Different numerical integration techniques are used in order to calculate wave coefficients and comparisons are given.Eventually, tests with the theoretical data and results of measured antennas are performed and results are discussed.

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Synthesis of Reactance 4‐Poles Which Produce Prescribed Insertion Loss Characteristics: Including Special Applications To Filter Design

1939-04-01

S. Darlington

Spontaneous Emission Probabilities at Radio Frequencies

1995-01-01

Edward M. Purcell

On the Theory of Noise in Radio Receivers with Square Law Detectors

1947-04-01

Mark Kac , A. J. F. Siegert

For the video output V of a receiver, consisting of an i-f stage, a quadratic detector, and a video amplifier, the probability density P(V) has been obtained for noise alone … For the video output V of a receiver, consisting of an i-f stage, a quadratic detector, and a video amplifier, the probability density P(V) has been obtained for noise alone and for noise and signal. The results are expressed in terms of eigenvalues and eigenfunctions of the integral equation ∫ 0∞K(t)ρ(s−t)f(t)dt=λf(s),where ρ(τ) is the i-f correlation function (i.e., the Fourier transform of the i-f power spectrum) and K(t) is the response function of the video amplifier (i.e., the Fourier transform of the video amplitude spectrum). Two special cases are discussed in which the integral equation can be solved explicitly. Approximations for general amplifiers are given in the limiting cases of wide and narrow videos. Some applications of the method to other problems are shown in Sections 7B and 9.

An overview of near-field antenna measurements

1986-01-01

Arthur D. Yaghjian

After a brief history of near-field antenna measurements with and without probe correction, the theory of near-field antenna measurements is outlined beginning with ideal probes scanning on arbitrary surfaces and … After a brief history of near-field antenna measurements with and without probe correction, the theory of near-field antenna measurements is outlined beginning with ideal probes scanning on arbitrary surfaces and ending with arbitrary probes scanning on planar, cylindrical, and spherical surfaces. Probe correction is introduced for all three measurement geometries as a slight modification to the ideal probe expressions. Sampling theorems are applied to determine the required data-point spacing, and efficient computational methods along with their computer run times are discussed. The major sources of experimental error defining the accuracy of typical planar near-field measurement facilities are reviewed, and present limitations of planar, cylindrical, and spherical near-field scanning are identified.

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From Approximations to Exact Relations for Characteristic Impedances

1969-05-01

Wolfgang Hilberg

Approximations for the characteristic impedance of a special two conductor stripline and for the general function K/K' are derived by a transformation method recently described in the literature; the first, … Approximations for the characteristic impedance of a special two conductor stripline and for the general function K/K' are derived by a transformation method recently described in the literature; the first, second, and third approximations having a greatest relative error of the order of 10/sup -3/, 10/sup -6/, and 10/sup -12/, respectively. They can be introduced into an algorithm which is based on elementary conformal mappings, and thus further approximations with rapidly vanishing errors can be derived. The results agree with those for the function K/K' obtained by elliptic integral theory. Obviously no such theory is needed to calculate characteristic impedances or the function K/K' with arbitrary accuracy. The advantages of the new method are illustrated for shielded coupled-strip transmission lines, for which an extended diagram with extreme parameter values has been worked out.

Electromagnetic shielding performance of carbon foams

2012-01-06

Franco Moglie , Davide Micheli , Susanna Laurenzi +2 more

Implementing the fast multipole method in three dimensions

1991-06-01

K. E. Schmidt , Michael A. Lee

The electromagnetic radiation from a finite antenna

1975-01-01

M. A. Uman , D. Kenneth McLain , E. Philip Krider

Textbooks rarely give time−domain solutions to antenna problems. For the case of a finite linear antenna along which a fixed current waveform propagates, we present analytical time−domain solutions for the … Textbooks rarely give time−domain solutions to antenna problems. For the case of a finite linear antenna along which a fixed current waveform propagates, we present analytical time−domain solutions for the electric and magnetic radiation (far) fields. We also give computer solutions for the total (near and far) fields. The current waveform used as an example in the computer calculations approximates that of a lightning return−stroke, a common geophysical example of the type of radiation source under consideration.

Reverberation Chamber Techniques for Determining the Radiation and Total Efficiency of Antennas

2012-01-31

Christopher L. Holloway , Haider A. Shah , Ryan J. Pirkl +3 more

Reverberation chambers are becoming a popular alternative testing facility for a wide range of electromagnetic applications. Because of the statistical environment created inside a reverberation chamber, they offer a unique … Reverberation chambers are becoming a popular alternative testing facility for a wide range of electromagnetic applications. Because of the statistical environment created inside a reverberation chamber, they offer a unique test facility. In particular, these chambers are ideally suited for performing radiated power measurements of either an antenna or device under test, and as such, it is possible to determine the efficiency of antennas. There have been several reverberation chamber techniques proposed over the years for measuring the antenna efficiency; however, these techniques require either the use of a reference antenna (i.e., an antenna with a known efficiency) and/or require the assumption that the two antennas used in the test have identical efficiencies. In this paper, we present three different approaches for determining both the radiation and total efficiencies of an unknown antenna that overcome these limitations and assumptions. We present a one-antenna approach, a two-antenna approach, and a three-antenna approach. We present measured data for three different antennas in order to compare these three approaches. We also discuss the uncertainties related to these types of measurements.

Baseband-pulse-antenna techniques

1994-02-01

D. Lamensdorf , L. Susman

Frequency-domain concepts and terminology are commonly used to describe antennas. These are very satisfactory for a CW or narrowband application. However, their validity is questionable for an instantaneous wideband excitation. … Frequency-domain concepts and terminology are commonly used to describe antennas. These are very satisfactory for a CW or narrowband application. However, their validity is questionable for an instantaneous wideband excitation. Time-domain and/or wideband analyses can provide more insight and more effective terminology. Two approaches for this time-domain analysis have been described. The more complete one uses the transfer function, a function which describes the amplitude and phase of the response over the entire frequency spectrum. While this is useful for evaluating the overall response of a system, it may not be practical when trying to characterize an antenna's performance, and trying to compare it with that of other antennas. A more convenient and descriptive approach uses time-domain parameters, such as efficiency, energy pattern, receiving area, etc., with the constraint that the reference or excitation signal is known. The utility of both approaches, for describing the time-domain performance, was demonstrated for antennas which are both small and large, in comparison to the length of the reference signal. The approaches have also been used for other antennas, such as arrays, where they also could be applied to measure the effects of mutual impedance, for a wide-bandwidth signal. The time-domain ground-plane antenna range, on which these measurements were made, is suitable for symmetric antennas. However, the approach can be readily adapted to asymmetric antennas, without a ground plane, by using suitable reference antennas.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Electromagnetic scattering by surfaces of arbitrary shape

1982-05-01

S. Rao , Donald R. Wilton , A.W. Glisson

The electric field integral equation (EFIE) is used with the moment method to develop a simple and efficient numerical procedure for treating problems of scattering by arbitrarily shaped objects. For … The electric field integral equation (EFIE) is used with the moment method to develop a simple and efficient numerical procedure for treating problems of scattering by arbitrarily shaped objects. For numerical purposes, the objects are modeled using planar triangular surfaces patches. Because the EFIE formulation is used, the procedure is applicable to both open and closed surfaces. Crucial to the numerical formulation is the development of a set of special subdomain-type basis functions which are defined on pairs of adjacent triangular patches and yield a current representation free of line or point charges at subdomain boundaries. The method is applied to the scattering problems of a plane wave illuminated flat square plate, bent square plate, circular disk, and sphere. Excellent correspondence between the surface current computed via the present method and that obtained via earlier approaches or exact formulations is demonstrated in each case.

Formulas for the Skin Effect

1942-09-01

H.A. Wheeler

At radio frequencies, the penetration of currents and magnetic fields into the surface of conductors is governed by the skin effect. Many formulas are simplified if expressed in terms of … At radio frequencies, the penetration of currents and magnetic fields into the surface of conductors is governed by the skin effect. Many formulas are simplified if expressed in terms of the "depth of penetration," which has merely the dimension of length but involves the frequency and the conductivity and permeability of the conductive material. Another useful parameter is the "surface resistivity" determined by the skin effect, which has simply the dimension of resistance. These parameters are given for representative metals by a convenient chart covering a wide range of frequency. The "incremental-inductance rule" is given for determining not only the effective resistance of a circuit but also the added resistance caused by conductors in the neighborhood of the circuit. Simple formulas are given for the resistance of wires, transmission lines, and coils; for the shielding effect of sheet metal; for the resistance caused by a plane or cylindrical shield near a coil; and for the properties of a transformer with a laminated iron core.

Generation of Standard EM Fields Using TEM Transmission Cells

1974-11-01

M. L. Crawford

A new technique developed at the National Bureau of Standards (NBS) for establishing standard, uniform, electromagnetic (EM) fields in a shielded environment is described. The technique employs transverse electromagnetic (TEM) … A new technique developed at the National Bureau of Standards (NBS) for establishing standard, uniform, electromagnetic (EM) fields in a shielded environment is described. The technique employs transverse electromagnetic (TEM) transmission cells that operate as 50 Ω impedance-matched systems. A uniform TEM field is established inside a cell at any frequency of interestbelow that for which higher order modes begin to propagate. Standard field strength levels from 10 μV/m to 500 V/m can be established with uncertainties of less than 1.0 dB to 2.0 dB inside the NBS cells for frequencies from dc to 500 MHz. The cells are especially useful for calibrating EM radiation hazard meters, for emission and susceptibility testing of small to medium sized equipment, and for special low level calibration of very sensitive field strength meters.

Error analysis techniques for planar near-field measurements

1988-06-01

A.C. Newell

A combination of techniques is described for reliably estimating the magnitude of each error arising in planar near-field measurements. They include mathematical analysis, computer simulation, and measurement tests. There are … A combination of techniques is described for reliably estimating the magnitude of each error arising in planar near-field measurements. They include mathematical analysis, computer simulation, and measurement tests. There are three primary applications for these tests: in designing a measurement facility, the requirements of each part of the measurement system can be specified to meet a given level of accuracy; during actual measurements, the experimenter can identify, and reduce where necessary, potential sources of error in the measurement; and when a measurement has been completed, the estimated uncertainty in the measurement can be obtained with confidence and ease. The latter application has been used in many measurements to verify that the planar near-field technique produces high-accuracy results competitive with any other measurement technique.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

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Plane wave integral representation for fields in reverberation chambers

1998-01-01

David A. Hill

A plane wave integral representation is presented for well-stirred fields in a reverberation chamber. The representation automatically satisfies Maxwell's equations in a source-free region and the statistical properties of the … A plane wave integral representation is presented for well-stirred fields in a reverberation chamber. The representation automatically satisfies Maxwell's equations in a source-free region and the statistical properties of the fields are introduced through the angular spectrum, which is taken to be a random variable. Starting with fairly simple and physically appropriate assumptions for the angular spectrum, a number of properties of the electric and magnetic fields and the power received by an antenna or a test object are derived. Many of these properties and test object responses are in agreement with other theories or with measured results. An important result for radiated immunity testing is that the ensemble (stirring) average of received power is equal to the average over plane wave incidence and polarization.

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Applications of the Near-Field Techniques in EMC Investigations

2007-08-01

David Baudry , Christian Arcambal , Anne Louis +2 more

A completely automatic near-field mapping system has been developed within the Research Institute for Electronic Embedded Systems (IRSEEM) in order to determine the electromagnetic field created by electronic systems and … A completely automatic near-field mapping system has been developed within the Research Institute for Electronic Embedded Systems (IRSEEM) in order to determine the electromagnetic field created by electronic systems and components. This test bench uses a 3-D positioning system of the probe to make accurate measurements. This paper presents some applications of the near-field techniques in EMC investigations. In the first part, near-field measurements are used to locate precisely the electromagnetic sources of a limiter device. In the second part, we present an equivalent model of the radiated emission of an integrated circuit. In the last part, the near-field test bench is used to characterize faults in a cable.

Standard probes for electromagnetic field measurements

1993-01-01

Motohisa Kanda

Discusses various standard antennas for measuring radio-frequency electric and magnetic fields. A theoretical analysis of each antenna's receiving characteristics is summarized and referenced. The standard probes described are an electrically … Discusses various standard antennas for measuring radio-frequency electric and magnetic fields. A theoretical analysis of each antenna's receiving characteristics is summarized and referenced. The standard probes described are an electrically short dipole, a resistively-loaded dipole, a half-wave dipole, an electrically small loop, and a resistively-loaded loop. A single-turn loop designed for simultaneous measurement of the electric and magnetic components of near-fields and other complex electromagnetic environments is also described. Each type of antenna demonstrates a different compromise between broadband frequency response and sensitivity.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Analytical formulation for the shielding effectiveness of enclosures with apertures

1998-01-01

Martin P. Robinson , T.M. Benson , C. Christopoulos +5 more

An analytical formulation has been developed for the shielding effectiveness of a rectangular enclosure with an aperture. Both the magnetic and electric shielding may be calculated as a function of … An analytical formulation has been developed for the shielding effectiveness of a rectangular enclosure with an aperture. Both the magnetic and electric shielding may be calculated as a function of frequency, enclosure dimensions, aperture dimensions and position within the enclosure. Theoretical values of shielding effectiveness are in good agreement with measurements. The theory has been extended to account for circular apertures, multiple apertures, and the effect of the enclosure contents.

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Representation of electromagnetic fields over arbitrary surfaces by a finite and nonredundant number of samples

1998-03-01

O.M. Bucci , Claudio Gennarelli , C. Savarese

It is shown that the electromagnetic (EM) field, radiated or scattered by bounded sources, can be accurately represented over a substantially arbitrary surface by a finite number of samples even … It is shown that the electromagnetic (EM) field, radiated or scattered by bounded sources, can be accurately represented over a substantially arbitrary surface by a finite number of samples even when the observation domain is unbounded. The number of required samples is nonredundant and essentially coincident with the number of degrees of freedom of the field. This result relies on the extraction of a proper phase factor from the field expression and on the use of appropriate coordinates to parameterize the domain. It is demonstrated that the number of degrees of freedom is independent of the observation domain and depends only on the source geometry. The case of spheroidal sources and observation domains with rotational symmetry is analyzed in detail and the particular cases of spherical and planar sources are explicitly considered. For these geometries, precise and fast sampling algorithms of central type are presented, which allow an efficient recovery of EM fields from a nonredundant finite number of samples. Such algorithms are stable with respect to random errors affecting the data.

Dipole radiation in the presence of a conducting half-space

1966-08-01

Ronold W. P. King

Electromagnetic wave absorbers and anechoic chambers through the years

1973-07-01

W. Emerson

A historical summary of the development of microwave absorbing materials and anechoic chambers is presented. A historical summary of the development of microwave absorbing materials and anechoic chambers is presented.

Shielding theory and practice

1988-08-01

Richard B. Schulz , Vellar Plantz , David Brush

Plane-wave shielding theory is developed and discussed for a number of important cases such as single, double, and laminated shields. For application to design, the basic expressions are modified and … Plane-wave shielding theory is developed and discussed for a number of important cases such as single, double, and laminated shields. For application to design, the basic expressions are modified and plotted with universal parameters for convenient use in performance calculations of both solid and perforated sheets. Performances of solid copper and iron shields have been calculated and are presented in both tabular and graphical form. For these and other materials, measurement results of various experiments are tabulated for a number of different material forms and for various incident-wave impedances. Some consideration is given to shielding discontinuities and trends in modern shielding enclosures.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Nonorthogonal PEEC formulation for time- and frequency-domain EM and circuit modeling

2003-05-01

Albert E. Ruehli , Giulio Antonini , J. Esch +3 more

Electromagnetic solvers based on the partial element equivalent circuit (PEEC) approach have proven to be well suited for the solution of combined circuit and EM problems. The inclusion of all … Electromagnetic solvers based on the partial element equivalent circuit (PEEC) approach have proven to be well suited for the solution of combined circuit and EM problems. The inclusion of all types of Spice circuit elements is possible. Due to this, the approach has been used in many different tools. Most of these solvers have been based on a rectangular or Manhattan representation of the geometries. In this paper, we systematically extend the PEEC formulation to nonorthogonal geometries since many practical EM problems require a more general formulation. Importantly, the model given in this paper is consistent with the classical PEEC model for rectangular geometries. Some examples illustrating the application of the approach are given for both the time and frequency domain.

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Antenna characterization in the time domain

1997-07-01

Amir Shlivinski , Ehud Heyman , R. Kastner

A theory for a complete far-field transmit-receive system characterization of short-pulse antennas is derived in the time domain. The transmit-receive antenna system is characterized by a set of cascaded operators, … A theory for a complete far-field transmit-receive system characterization of short-pulse antennas is derived in the time domain. The transmit-receive antenna system is characterized by a set of cascaded operators, which transform the source waveform and power into similar quantities at the receiving antenna terminals. Two such sets are defined. The first one is phrased in terms of the wave-type "time-dependent effective-height" operator, while the second one is defined in terms of the energy-type "gain operator". Both definitions fit within a complete transmit-receive system description, the latter being equivalent to the frequency-domain Friis equation. However, these operators are derived entirely in the context of the time-domain field equation. The starting point in the time-domain analysis of the effective height is the slant stack transform (SST) of the time-dependent current distribution in a manner equivalent to the spatial Fourier transform used in the frequency domain. The vector autocorrelation of the transmitting effective height is then used to define the time-dependent gain operator under impulsive source excitation. Time-domain reciprocity leads to the definitions of antenna parameters under receiving conditions and the corresponding equivalent circuit. The parameters defined in this way fit within a consistent transmit-receive convolution operator, operating on the autocorrelation of the input signal. This independent time-domain representation is thus similar to the frequency-domain representation. However, unlike the conventional frequency-domain circuit parameters, which relate voltage and current amplitudes, the time-domain circuit representation is based on incident and reflected wave-type constituents. In addition, the use of appropriate norms facilitates the transformation of our operators to stand-alone figures of merits. The general concepts developed are demonstrated for a short dipole antenna.

Reconstruction of Equivalent Currents Distribution Over Arbitrary Three-Dimensional Surfaces Based on Integral Equation Algorithms

2007-12-01

Yuri Álvarez , Fernando Las‐Heras , Marcos R. Pino

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A technique for the determination of the equivalent currents distribution from a known radiated field is described. This Inverse Radiation Problem is solved through an Integral Equation … <para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A technique for the determination of the equivalent currents distribution from a known radiated field is described. This Inverse Radiation Problem is solved through an Integral Equation algorithm that allows the characterization of antennas of complex geometry both for near field to far field (NF-FF) transformation purposes as well as for diagnostic tasks. The algorithm is based on the representation of the radiating structure by means of a set of equivalent currents over a three-dimensional (3-D) surface that can be fitted to the arbitrary geometry of the antenna. The innovative formulation uses an integral equation involving the electric field due to the currents tangential components to the represented antenna 3-D surface. For that purpose, both the magnetic and electric equivalent currents are considered in the integral equations. Regularization techniques are also introduced to improve the convergence of the proposed iterative solution. The paper concludes with several results related to the practical verification of the Equivalence Principle and the characterization of a horn antenna. </para>

Basic theory of probe-compensated near-field measurements

1978-05-01

D. Paris , W. Marshall Leach , Edward Bennett Joy

The general problem concerning the interaction of a probe antenna with the near field of an arbitrary antenna is considered. The application of the Lorentz reciprocity theorem to the problem … The general problem concerning the interaction of a probe antenna with the near field of an arbitrary antenna is considered. The application of the Lorentz reciprocity theorem to the problem of determining antenna characteristics, including the far-field pattern, is presented. The data required to correct for the directional effects of the probe, the effect of probe correction on the measured data, and the attendant mathematical computations in rectangular systems are described. Extensions to cylindrical and spherical systems are discussed.

On the Use of Reverberation Chambers to Simulate a Rician Radio Environment for the Testing of Wireless Devices

2006-11-01

Christopher L. Holloway , David A. Hill , John M. Ladbury +3 more

With the proliferation of wireless devices in recent years, there is a growing need to test the operation and functionality of these various devices in different multipath environments, ranging from … With the proliferation of wireless devices in recent years, there is a growing need to test the operation and functionality of these various devices in different multipath environments, ranging from line-of-sight environment to a pure Rayleigh environment. In this paper we discuss how a reverberation chamber can be used to simulate a controllable Rician radio environment for the testing of a wireless device. We show that by varying the characteristics of the reverberation chamber and/or the antenna configurations in the chamber, any desired Rician K-factor can be obtained. Expressions for the desired K-factor as a function of the chamber and antenna characteristics will be presented. Experimental results are presented to illustrate the validity of these expressions, to show how the reverberation chamber can be used to simulate different multipath environments, and to show the realization of a controlled K-factor test facility. We present both a one-antenna and a two-antenna test configuration approach

Near-field to near/far-field transformation for arbitrary near-field geometry utilizing an equivalent electric current and MoM

1999-03-01

Tapan K. Sarkar , A. Taaghol

Presented here is a method for computing near- and far-field patterns of an antenna from its near-field measurements taken over an arbitrarily shaped geometry. This method utilizes near-field data to … Presented here is a method for computing near- and far-field patterns of an antenna from its near-field measurements taken over an arbitrarily shaped geometry. This method utilizes near-field data to determine an equivalent electric current source over a fictitious surface which encompasses the antenna. This electric current, once determined, can be used to ascertain the near and the far field. This method demonstrates the concept of analytic continuity, i.e., once the value of the electric field is known for one region in space, from a theoretical perspective, its value for any other region can be extrapolated. It is shown that the equivalent electric current produces the correct fields in the regions in front of the antenna regardless of the geometry over which the near-field measurements are made. In this approach, the measured data need not satisfy the Nyquist sampling criteria. An electric field integral equation is developed to relate the near field to the equivalent electric current. A moment method procedure is employed to solve the integral equation by transforming it into a matrix equation. A least-squares solution via singular value decomposition is used to solve the matrix equation. Computations with both synthetic and experimental data, where the near field of several antenna configurations are measured over various geometrical surfaces, illustrate the accuracy of this method.

On the integral equations of thin wire antennas

1965-05-01

K.K. Mei

The feasibility of direct numerical calculations of antenna integral equations is investigated. It is shown that integral equation of Hallen's type is the most adequate for such applications. The extension … The feasibility of direct numerical calculations of antenna integral equations is investigated. It is shown that integral equation of Hallen's type is the most adequate for such applications. The extension of Hallen's integral equation to describe thin wire antennas of arbitrary geometry is accomplished, and results are presented for dipole, circular loops, and equiangular spiral antennas.

Determination of far-field antenna patterns from near-field measurements

1973-01-01

Richard Johnson , Harry Allen Ecker , John Searcy Hollis

In many cases, it is impractical or impossible to make antenna pattern measurements on a conventional far-field range; the distance to the radiating far field may be too long, it … In many cases, it is impractical or impossible to make antenna pattern measurements on a conventional far-field range; the distance to the radiating far field may be too long, it may be impractical to move the antenna from its operating environment to an antenna range, or the desired amount of pattern data may require too much time on a far-field range. For these and other reasons, it is often desirable or necessary to determine far-field antenna patterns from measurements made in the radiating near-field region; three basic techniques for accomplishing this have proven to be successful. In the first technique, the aperture phase and amplitude distributions are sampled by a scanning field probe, and then the measured distributions are transformed to the far field. In the second technique, a plane wave that is approximately uniform in amplitude is created by a feed and large reflector in the immediate vicinity of the test antenna. And in the third technique, the test antenna is focused within the radiating near-field region, patterns are measured at the reduced range, and then the antenna is refocused to infinity. Each of these techniques is discussed, and the various advantages and limitations of each technique are presented.

Statistical-Physical Models of Electromagnetic Interference

1977-08-01

David Middleton

Most man-made and natural electromagnetic interference, or "noise," are highly non-Gaussian random processes, whose degrading effects on system performance can be severe, particularly on most conventional systems, which are designed … Most man-made and natural electromagnetic interference, or "noise," are highly non-Gaussian random processes, whose degrading effects on system performance can be severe, particularly on most conventional systems, which are designed for optimal or near optimal performance against normal noise. In addition, the nature, origins, measurement, and prediction of the general EM interference environment are a major concern of any adequate spectral management program. Accordingly, this study is devoted to the development of analytically tractable, experimentally verifiable, statistical-physical models of such electromagnetic interference. Here, classification into three major types of noise is made: Class A (narrow band vis-á-vis the receiver), Class B (broad band vis-á-vis the receiver), and Class C (= Class A + Class B). First-order statistical models are constructed for the Class A and Class B cases. In particular, the APD (a posteriori probability distribution) or exceedance probability, PD, vis;P1 (ϵ > ϵo)A,B, (and the associated probability densities, pdf's w1(ϵ)A,B,[1]) of the envelope are obtained; (the phase is shown to be uniformly distributed in (0, 2π). These results are canonical, i.e., their analytic forms are invariant of the particular noise source and its quantifying parameter values, levels, etc. Class A interference is described by a 3-parameter model, Class B noise by a 6-parameter model.

EMI shielding measurements of conductive polymer blends

1992-04-01

N. Colaneri , L.W. Schacklette

Shielding efficiencies for a number of blends containing a variety of conductive fillers, including intrinsically conductive polymers, have been measured in the near field with a dual-chamber box and in … Shielding efficiencies for a number of blends containing a variety of conductive fillers, including intrinsically conductive polymers, have been measured in the near field with a dual-chamber box and in the far field with a transmission line fixture. Although all samples satisfied the classical good-conductor approximation, most of them exhibited a crossover from being electrically thin (thickness<skin depth) to being electrically thick (thickness>skin depth) over the frequency range of interest, 1 MHz to 3 GHz. The theoretical relations for both near-field and far-field shielding which are prevalent in the literature do not accurately describe this region of crossover. The authors have derived expressions which describe the behavior accurately over the entire range of interest. Far-field shielding efficiencies as high as 70 dB at 1 GHz were measured for purely organic composites consisting of an intrinsically conductive polymer, polyaniline, dispersed in a thermoplastic matrix.<<ETX>>

Probe compensated near-field measurements on a cylinder

1973-07-01

W. Marshall Leach , D. Paris

A new method is developed for determining the farfield pattern of an antenna from probe compensated near-field measurements over the surface of a right circular cylinder enclosing the antenna. The … A new method is developed for determining the farfield pattern of an antenna from probe compensated near-field measurements over the surface of a right circular cylinder enclosing the antenna. The method is derived by first expanding both the field radiated by the antenna and the field radiated by the measurement probe, when it is used as a transmitter, into cylindrical wave expansions. The Lorentz reciprocity theorem is then used to solve for the field radiated by the antenna from the probe output voltage. It is shown rigorously that the antenna pattern can be determined independently of the characteristics of the measurement probe provided that certain calibration data are known. A method for determining these data from the measured far field radiated by the probe is described. It is shown that the necessary numerical integration can be performed with the fast Fourier transform algorithm. Experimental results are presented to validate the theory and to demonstrate its practicality from a measurement and computational viewpoint.

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Planar near-field to far-field transformation using an equivalent magnetic current approach

1992-11-01

Peter Petré , Tapan K. Sarkar

An alternative method is presented for computing far-field antenna patterns from near-field measurements. The method utilizes the near-field data to determine equivalent magnetic current sources over a fictitious planar surface … An alternative method is presented for computing far-field antenna patterns from near-field measurements. The method utilizes the near-field data to determine equivalent magnetic current sources over a fictitious planar surface that encompasses the antenna, and these currents are used to ascertain the far fields. Under certain approximations, the currents should produce the correct far fields in all regions in front of the antenna regardless of the geometry over which the near-field measurements are made. An electric field integral equation (EFIE) is developed to relate the near fields to the equivalent magnetic currents. The method of moments is used to transform the integral equation into a matrix one. The matrix equation is solved with the conjugate gradient method, and in the case of a rectangular matrix, a least-squares solution for the currents is found without explicitly computing the normal form of the equation. Near-field to far-field transformation for planar scanning may be efficiently performed under certain conditions. Numerical results are presented for several antenna configurations.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Electromagnetic penetration through apertures in conducting surfaces

1978-01-01

C.M. Butler , Yahya Rahmat‐Samii , R. Mittra

In designing hardened systems, one must be able to characterize as well as quantitatively determine the penetration of EMP signals through apertures of general shapes in structures of varying configurations. … In designing hardened systems, one must be able to characterize as well as quantitatively determine the penetration of EMP signals through apertures of general shapes in structures of varying configurations. In this paper a tutorial review of a number of methods for analyzing such aperture problems is presented with an emphasis on techniques. The discussion presented herein is reasonably self-contained and is supplemented by references to classical as well as current approaches to the aperture problem. An extensive set of representative numerical results is included.

Aperture excitation of electrically large, lossy cavities

1994-01-01

David A. Hill , M.T. Ma , Arthur Ondrejka +3 more

We present a theory based on power balance for aperture excitation of electrically large, lossy cavities. The theory yields expressions for shielding effectiveness, cavity Q, and cavity time constant. In … We present a theory based on power balance for aperture excitation of electrically large, lossy cavities. The theory yields expressions for shielding effectiveness, cavity Q, and cavity time constant. In shielding effectiveness calculations, the incident field can be either a single plane wave or a uniformly random field to model reverberation chamber or random field illumination. The Q theory includes wall loss, absorption by lossy objects within the cavity, aperture leakage, and power received by antennas within the cavity. Extensive measurements of shielding effectiveness, cavity Q, and cavity time constant were made on a rectangular cavity, and good agreement with theory was obtained for frequencies from 1 to 18 GHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Materials for Electromagnetic Interference Shielding

2000-06-01

D.D.L. Chung

ICNIRP STATEMENT ON THE “GUIDELINES FOR LIMITING EXPOSURE TO TIME-VARYING ELECTRIC, MAGNETIC, AND ELECTROMAGNETIC FIELDS (UP TO 300 GHz)”

2009-08-04

The International Commission on Non-Ionizing Radiation Protection

* ICNIRP, c/o BfS—G. Ziegelberger, Ingolstaedter Landstr. 1, 85764 Oberschleissheim, Germany. For correspondence contact G. Ziegelberger at the above address, or email at [email protected]. (Manuscript accepted 26 May 2009) * ICNIRP, c/o BfS—G. Ziegelberger, Ingolstaedter Landstr. 1, 85764 Oberschleissheim, Germany. For correspondence contact G. Ziegelberger at the above address, or email at [email protected]. (Manuscript accepted 26 May 2009)

GUIDELINES FOR LIMITING EXPOSURE TO TIME-VARYING ELECTRIC AND MAGNETIC FIELDS (1 Hz TO 100 kHz)

2010-12-01

International Commission on Non-Ionizing Radiation Protection

* ICNIRP Secretariat, c/o Gunde Ziegelberger, c/o Bundesamt für Strahlenschutz, Ingolstaedter Landstrasse 1, 85764 Oberschleissheim, Germany. For correspondence or reprints contact [email protected]. (Manuscript accepted 15 June 2010). * ICNIRP Secretariat, c/o Gunde Ziegelberger, c/o Bundesamt für Strahlenschutz, Ingolstaedter Landstrasse 1, 85764 Oberschleissheim, Germany. For correspondence or reprints contact [email protected]. (Manuscript accepted 15 June 2010).

Radar Cross Section

2004-01-01

Eugene F. Knott , John Shaeffer , Michael T. Tuley

Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of … Radar cross section (RCS) is a comparison of two radar signal strengths. One is the strength of the radar beam sweeping over a target, the other is the strength of the reflected echo sensed by the receiver. This book shows how the RCS gauge can be predicted for theoretical objects and how it can be measured for real targets. Predicting RCS is not easy, even for simple objects like spheres or cylinders, but this book explains the two exact forms of theory so well that even a novice will understand enough to make close predictions. Weapons systems developers are keenly interested in reducing the RCS of their platforms. The two most practical ways to reduce RCS are shaping and absorption. This book explains both in great detail, especially in the design, evaluation, and selection of radar absorbers. There is also great detail on the design and employment of indoor and outdoor test ranges for scale models or for full-scale targets (such as aircraft). In essence, this book covers everything you need to know about RCS, from what it is, how to predict and measure, and how to test targets (indoors and out), and how to beat it.

Microwave Measurements

1958-01-01

Edward L. Ginzton , Yardley Beers

Radar Cross Section Measurements

1993-01-01

Eugene F. Knott

Broadband Low-Cost Normal Magnetic Field Probe for PCB Near-Field Measurement

2025-06-21

Ruichen Luo , Zheng He , Lixiao Wang | Sensors

This paper presents a broadband near-field probe designed for measuring the normal magnetic field (Hz) in radio frequency (RF) circuits operating within a frequency range of 2–8 GHz. The proposed … This paper presents a broadband near-field probe designed for measuring the normal magnetic field (Hz) in radio frequency (RF) circuits operating within a frequency range of 2–8 GHz. The proposed probe uses a cost-effective 4-layer printed circuit board (PCB) structure made with an FR-4 substrate. The probe primarily consists of an Hz detection unit, a broadband microstrip balun, and a coaxial-like output. The broadband balun facilitates the conversion from differential to single-ended signals, thereby enhancing the probe’s common-mode rejection capability. This design ensures that the probe achieves both cost efficiency and high broadband measurement performance. Additionally, this work investigates the feasibility of employing microstrip lines as calibration standards for the Hz probe. The probe’s structural parameters and magnetic field response were initially determined through simulations, and the calibration factor was subsequently verified by calibration experiments. In practical measurements, the field distributions above a microstrip line and a low-noise amplifier (LNA) were captured. The measured field distribution of the microstrip line was compared with simulation results to verify the probe’s performance. Meanwhile, the measured field distribution of the LNA was utilized to identify the radiating components within the amplifier.

Radio Frequency Interference, Its Mitigation and Its Implications for the Civil Aviation Industry

2025-06-18

A. I. Malik , Muzaffar Rao | Electronics

Radio Frequency Interference has emerged as a growing challenge for aviation safety and system integrity due to the increasing spectral overlap between communication technologies and aviation systems. This paper investigates … Radio Frequency Interference has emerged as a growing challenge for aviation safety and system integrity due to the increasing spectral overlap between communication technologies and aviation systems. This paper investigates the sources, types, and consequences of RFI in Global Navigation Satellite Systems, Instrument Landing Systems, and altimeters used in civil aviation. A detailed examination of both intentional and unintentional interference is presented, highlighting real-world incidents and simulated impact models. The study analyzes technical mechanisms such as receiver desensitization, intermodulation, and cross-modulation, and further explores UAV-based interference detection frameworks. Mitigation strategies are reviewed, including regulatory practices, spectrum filters, shielding architectures, and dynamic UAV sensing systems. Comparative insights into simulation results, shielding techniques, and regulatory gaps are discussed. The paper concludes with recommendations for enhancing current aviation standards and suggests a hybrid validation model combining in-flight measurements with simulation-based assessments. This research contributes to the understanding of electromagnetic vulnerabilities in aviation and provides a basis for future mitigation protocols.

Critical polarization suppression in the near-field interference of moving Huygens-like dipoles

2025-06-18

Xuhuinan Chen , Yuhan Zhong , Weili Ma +4 more | Optics Letters

Determination of electromagnetic shielding effectiveness using an enhanced absorber box method: theoretical, simulation, and experimental approaches

2025-06-17

Andrea Amaro , J. Torres , Adrián Suárez +5 more | Measurement Science and Technology

Abstract Accurate characterization of Shielding Effectiveness (SE) is essential for evaluating electromagnetic interference (EMI) shielding materials in high-frequency applications such as 5G communications, automotive, radar, and aerospace. Standardized methods like … Abstract Accurate characterization of Shielding Effectiveness (SE) is essential for evaluating electromagnetic interference (EMI) shielding materials in high-frequency applications such as 5G communications, automotive, radar, and aerospace. Standardized methods like ASTM D4935-18 and IEEE 299-2006 have frequency limitations, precise sample preparation, and demand complex experimental setups that can hinder practical implementation. This study presents an advanced characterization of an optimized Absorber Box methodology that enhances SE measurement accuracy, extends the frequency range beyond 1.5 GHz, and minimizes edge diffraction effects. The proposed approach provides a controlled testing environment in a more compact setup compared to anechoic chambers, facilitating practical implementation without compromising precision. The system’s reliability is validated through numerical simulations using Finite Element Method (FEM) analysis. Experimental results confirm the method’s ability to differentiate materials with different SE, demonstrating strong agreement between simulated and measured data. This approach offers a flexible and robust alternative to conventional SE measurement techniques, making it particularly advantageous for high-frequency shielding material characterization.&#xD;

Discrete Dipole Approximation

2025-06-16

Kotaro Kajikawa , Takayuki Okamoto | CRC Press eBooks

Romanian Satellite Demonstrator for Monitoring Ground RF Emissions

2025-06-01

Claudiu-Ionuț Cherciu , Dan Şelaru , Răzvan-George Bărtuşică +1 more | Revista Academiei Forţelor Terestre

Abstract The increasing reliance on radio communications for military, governmental, and civilian applications makes radio frequency (RF) monitoring a crucial aspect of national security. Unauthorized transmissions, spectrum interferences, and electronic … Abstract The increasing reliance on radio communications for military, governmental, and civilian applications makes radio frequency (RF) monitoring a crucial aspect of national security. Unauthorized transmissions, spectrum interferences, and electronic warfare threats pose significant challenges that require advanced detection and localization capabilities. Space-based systems provide a strategic advantage by offering wide-area coverage, persistent surveillance, and rapid signal acquisition. The CORVUS satellite is designed as a dedicated platform for detecting and localizing radio signals over Romania. By utilizing advanced signal processing and geolocation techniques, CORVUS enhances situational awareness, supports defense and intelligence operations, and strengthens the country’s ability to monitor the electromagnetic spectrum. This paper explores the satellite design, payload implementation, operational benefits, and security implications of the CORVUS satellite system.

Investigation of the influence of an electromagnetic absorber on the time and frequency characteristics of a differential transmission line

2025-06-01

V.A. Trubcheninov , Sergey Vlasov , Yevgeniy S. Zhechev | Journal of Radio Electronics

Modern trends in electronics development require the design of compact and high-performance devices operating under high levels of electromagnetic interference (EMI). A promising solution for ensuring the electromagnetic compatibility (EMC) … Modern trends in electronics development require the design of compact and high-performance devices operating under high levels of electromagnetic interference (EMI). A promising solution for ensuring the electromagnetic compatibility (EMC) of differential transmission lines (DTLs) is the use of electromagnetic absorbers (EAs). However, the influence of the absorber thickness on the time-domain and frequency-domain characteristics of integrated DTLs remains insufficiently studied. This study employs modeling methods implemented in the software tools TUSUR.EMC and COMSOL Multiphysics. A DTL on a GaAs substrate is considered, with the EA thickness varied from 0 to 20 µm. The investigation includes an analysis of transmission and reflection coefficients, signal integrity, and propagation delays. The research aims to determine the optimal EA thickness that provides maximum interference suppression while minimizing its impact on the useful signal. The results show that an EA with a thickness of 8 µm reduces interference amplitude by a factor of 1.4, increases signal arrival time by a factor of 1.15, and decreases the level of reflected signals in the stopband to minus 13.16 dB. However, the passband width decreases from 2.41 GHz (at H = 0) to 1.03 GHz (at H = 20 µm). Thus, the use of an EA with an optimal thickness significantly improves the EMC of integrated DTLs. The obtained results can be utilized in the design of high-frequency devices with enhanced immunity to interference.

Prediction of the Probability of IC Failure and Validation of Stochastic EM-Fields Coupling into PCB Traces Using a Bespoke RF IC Detector

2025-05-28

Arunkumar H. Venkateshaiah , J.F. Dawson , Martin A. Trefzer +4 more | Electronics

In this paper, a method of estimating the probability of susceptibility of a component on a circuit board to electromagnetic interference (EMI) is presented. The integrated circuit electromagnetic compatibility (IC … In this paper, a method of estimating the probability of susceptibility of a component on a circuit board to electromagnetic interference (EMI) is presented. The integrated circuit electromagnetic compatibility (IC EMC) standard IEC 62132-4 enables the assessment of the susceptibility of an IC by determining the forward power incident on each pin required to induce a malfunction. Although we focus on IC susceptibility, the method might be applied to other components and sub-circuits where the same information is known. Building upon a previously established numerical model capable of estimating the average coupled forward power at the end of a trace of a lossless PCB trace for a known load in a reverberant environment, this paper updates the model by incorporating PCB losses and utilizes the updated model to estimate the distribution of coupled forward power at the package pin over a number of boundary conditions in a reverberant field. Thus, the probability of failure can be predicted from the known component susceptibility level, the length, transmission line parameters, and the loading of the track to which it is attached. To validate this numerical model, the paper includes measurements obtained with a custom-designed RF IC detector, created for the purpose of measuring RF power coupled into the package pin via test PCB tracks.

Application of inventive problem solving (TRIZ) method in design of electromagnetic shielding enclosure

2025-05-25

Sunay Güler

Electromagnetic shielding targets to improve electromagnetic compatibility performance of electronic devices and systems. Metallic enclosures are the most common electromagnetic shielding apparatus thanks to their good electrical conductivity and wall … Electromagnetic shielding targets to improve electromagnetic compatibility performance of electronic devices and systems. Metallic enclosures are the most common electromagnetic shielding apparatus thanks to their good electrical conductivity and wall thickness. Shielding effectiveness (SE) is a measure of performance of the shielding enclosure. Slots or apertures located on the walls of the enclosure for various reasons have negative impact on SE since they allow electromagnetic interference leakage onto electronic circuits. This study proposes technical solutions which aim to improve SE in design of the electromagnetic shielding enclosure by applying inventive problem solving (TRIZ) method. Three engineering contradictions are generated and linked with the system parameters of TRIZ which are used as indicators within the contradiction matrix to obtain relevant inventive principles for creating technical solutions. In this context, analysis of SE based on each technical solution is performed and comparison studies are presented based on their impact on SE.

Double microwave shielding

2025-05-20

NULL AUTHOR_ID

A TEST STAND OF SIMPLIFIED DESIGN FOR DETERMINING THE CRITERION LEVELS OF DAMAGE TO RADIOELECTRONIC COMPONENTS WHEN EXPOSED TO POWERFUL PULSES OF ELECTROMAGNETIC ENERGY

2025-05-19

Nina Filimonenko , Kostiantyn Filimonenko , Nataliia Smirinska +2 more

Abstract—this article examines how to improve experimental research for field conditions of resistance to a powerful electromagnetic pulse of radio-electronic equipment made on the basis of COTS technology, in particular … Abstract—this article examines how to improve experimental research for field conditions of resistance to a powerful electromagnetic pulse of radio-electronic equipment made on the basis of COTS technology, in particular in the nanosecond range of pulse duration. A test stand is proposed for tentatively determining the criterion levels of damage to radio-electronic components under the influence of powerful pulses of electromagnetic energy.

Measurement Grid Optimization for OTA Testing of 5G Smart Watches

2025-05-19

Xudong An , F. Liu , Meijun Qu +1 more

Over-the-air (OTA) testing is crucial for optimizing wireless performance of 5G smart watches and improving their user experience. However, the current required test time is so long that it is … Over-the-air (OTA) testing is crucial for optimizing wireless performance of 5G smart watches and improving their user experience. However, the current required test time is so long that it is almost impossible to complete the entire OTA testing without recharging and repositioning, which is unacceptable for the industry. Therefore, test-time reduction is significant. The objective of this work is to optimize measurement grids for OTA testing of 5G smart watches, which balance accuracy with efficiency. In this research, passive patterns from a typical 5G commercial smart watch are measured at different bands as reference patterns, which represent general radiation properties of 5G commercial smart watches. The effect of various coarse grids on OTA testing precision is characterized quantitatively by analyzing their accuracy in reconstructing reference patterns. The related measurement uncertainty (MU) terms are then evaluated and determined quantitatively based on statistical analysis. According to the derived MU limits for grid configurations, reducing grid points from currently required 62 (30/30) to 26 (45/45), and from 266 (15/15) to 62 (30/30) could save roughly 60% and 75% of the test time, respectively, with an uncertainty increase of 0.1 dB for both Total Isotropic Sensitivity (TIS) and Total Radiated Power (TRP) testing, which is considered acceptable. Furthermore, the feasibility of the proposed MU analysis and recommended grids have been experimentally verified.

Image-Based Near-Field to Far-Field Transformation

2025-05-13

Hirokazu Kobayashi

This chapter discusses the theory of near-field to far-field transformation (NFFFT) for the radar cross section (RCS) of a radar target such as an aircraft. The RCS is one of … This chapter discusses the theory of near-field to far-field transformation (NFFFT) for the radar cross section (RCS) of a radar target such as an aircraft. The RCS is one of the most important metrics used in the design and evaluation of radar and electronic warfare systems. When the electrical size of the target under test is large, the probe antenna measuring the waves scattered by the object has to be placed far enough away from the target to illuminate the plane wave. If the frequency and wavelength are f and λ, respectively, and the maximum dimension of the target is D, the far distance R is generally evaluated as R>2D2/λ. For example, when D=3 m and f=10 GHz, R=600 m is an unrealistic condition. It is therefore conceivable that some method might be needed to theoretically transform the near-field scattering of the target into a far-field. As in the approach of this chapter, when a radar image is obtained, it is assumed that a far-field can be evaluated by considering the image as a secondary wave source. Based on this concept, the relationship between the radar image and the three-dimensional (3D) RCS can be derived. The theoretical validity is proved by numerical calculations by comparison with actual measurement data. The interesting result is that the unwanted waves can be suppressed by proper processing of the images containing the unwanted waves. The equivalence between time-domain processing, such as fast Fourier transform (FFT), and spatial-domain processing in image data is confirmed.

Prototype Antenna Array for Near-Field Surface Scanning of Magnetic Field

2025-05-12

Timur I. Tretyakov , Valeriy A. Semenyuk | 2022 International Conference on Industrial Engineering, Applications and Manufacturing (ICIEAM)

Performance Evaluation and Calibration of Electromagnetic Field (EMF) Area Monitors Using a Multi-Wire Transverse Electromagnetic (MWTEM) Transmission Line

2025-05-05

R. Azaro , Roberto Franchelli , Alessandro Gandolfo

The exposure levels generated by environmental electromagnetic field (EMF) sources can be measured and monitored by employing EMF area monitors. The operating spectrum of environmental EMF sources is not limited … The exposure levels generated by environmental electromagnetic field (EMF) sources can be measured and monitored by employing EMF area monitors. The operating spectrum of environmental EMF sources is not limited to high frequencies (f > 30 MHz) but also extends to low frequencies (f < 30 MHz), where sources associated, for example, with radio transmitters typically generate non-negligible field contributions. For this reason, professional EMF area monitors can be equipped with different field sensors, properly calibrated according to standardized procedures. Because low-frequency electric fields are very sensitive to environmental boundary conditions, equipping an EMF area monitor with electric field sensors, previously calibrated as stand-alone devices, can lead to measurement errors due to field perturbations introduced by the physical structure of the area monitor itself. This paper describes the activities carried out to assess the performance of an EMF area monitor in simulated realistic conditions and calibrate it in the 300 kHz–20 MHz frequency band. The activities were conducted using a multi-wire transverse electromagnetic (MWTEM) transmission line as a controlled electric field source, with dimensions suitable for exposure of the entire structure of the EMF area monitor. In view of using this approach to calibrate the area monitors as a whole instead of the individual sensors, the uniformity of the electric field generated by the available MWTEM transmission line was analyzed in detail both numerically and experimentally. Finally, the results of the evaluation and calibration of an area monitor are reported and discussed.

Correction of non-anechoic antenna measurements using matrix pencil algorithm with adaptively adjusted setup

2025-05-01

Adrian Bekasiewicz

Short‐Dipole Sensor Response Linearization Through Physics‐Informed Neural Networks

2025-05-01

Alessandro Fasse , R. A. Meyer , Esra Neufeld +3 more

ABSTRACT Short‐dipole diode sensors loaded with highly resistive lines are commonly used to measure the time‐averaged square of the high‐frequency electromagnetic field amplitude directly. Their precision, simplicity, broadband, high dynamic … ABSTRACT Short‐dipole diode sensors loaded with highly resistive lines are commonly used to measure the time‐averaged square of the high‐frequency electromagnetic field amplitude directly. Their precision, simplicity, broadband, high dynamic range capability, and minimal scattering make them ideal for application in the near‐field of sources, particularly for demonstrating compliance with exposure limits. However, the usage of these sensors to cover multiple orders of magnitude of field amplitude requires signal‐specific linearization of the sensor response. Traditionally, linearization had been performed for each signal or modulation by measurement and, more recently, by simulations based on a calibrated sensor model. These approaches have become prohibitively expensive with the launch of the fifth generation of mobile communication (5G), which added thousands of diverse and complex modulation schemes. In response to these challenges, we first developed an innovative approach to accelerate sensor model simulations with an enhancement of accuracy, which allows us to subsequently establish a data set comprising a large number of probe parameters and signal characteristic configurations. Subsequently, a physics‐informed neural network (PINN) was trained with readily accessible signal characteristics to obtain on‐the‐fly linearization parameters with acceptable uncertainties across the relevant dynamic range. In contrast to traditional artificial intelligence (AI) models that predominantly rely on pattern recognition from precomputed data, our approach ensures that the model captures the intrinsic relationships and system dynamics inherent to the physical phenomena under study. Our AI‐based approach achieves an error below 0.4 dB at peak specific absorption rate (SAR) values of up to . In addition, AI accelerates the determination of linearization parameters by a factor 34,000 and reduces storage requirements 350,000 times, allowing linearization parameters to be computed on site.

Experimental Research and Development of Nonlinearity Models for FR1 Range Mixers for Electromagnetic Compatibility Analysis

2025-04-29

Eugene Sinkevich , Vladimir Mordachev , Wan Fayu +2 more

By using the technology of double-frequency testing, an experimental analysis of nonlinear properties of low-power radio-frequency mixers is performed at frequencies of the n7 band allocated in Belarus for 4G … By using the technology of double-frequency testing, an experimental analysis of nonlinear properties of low-power radio-frequency mixers is performed at frequencies of the n7 band allocated in Belarus for 4G mobile communication systems and the n78 band that is planned to be used in Belarus for 5G mobile communications. Based on the results of the measurements of mixer characteristics (the double-frequency characteristics, single-tone amplitude characteristics, as well as two-tone amplitude characteristics and dynamic ranges for 3 rd -, 5 th -, 7 th -, and 9 th -order intermodulation) in the harmonic zone of the useful signal, high-order polynomial models describing the transfer characteristics of the considered mixers are synthesized. These models are intended to analyze the effect of radio-frequency electromagnetic interference on radio links behavior in case of a large dynamic range of input signals by using the discrete nonlinear modeling technique. The obtained models provide high adequacy and computational efficiency of quantitative analysis of nonlinear processes and radio interference occurring in receivers of 4G/5G/6G radio networks in a complex electromagnetic environment.

Electromagnetic Shielding Analysis Using Hilbert-Huang Transform

2025-04-29

Yuya Kobari , Y. Shimada , Ran Dong +1 more

In this study, the Hilbert-Huang Transform (HHT) and other frequency analysis methods, Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT), are employed to numerically analyze electromagnetic phenomena with strong … In this study, the Hilbert-Huang Transform (HHT) and other frequency analysis methods, Short-Time Fourier Transform (STFT) and Continuous Wavelet Transform (CWT), are employed to numerically analyze electromagnetic phenomena with strong non-linearity. In the numerical experiments, electromagnetic wave propagation simulations using the Finite-Difference Time-Domain (FDTD) method are performed to reproduce the behavior of electromagnetic shielding effects leaking from the shielding plate. The obtained results were analyzed using the HHT, STFT, and CWT methods; the HHT analysis showed that electromagnetic waves around the input wavelength 2.45 GHz leak significantly from the shielding plate. On the other hand, the STFT did not accurately resolve the signal, and the CWT unexpectedly showed strong amplitudes in the low-frequency region. These results suggest that HHT performs better in analyzing signals with strong non-linearity and provides more accurate results than other methods.

A radio-frequency quadrupole prototype additively manufactured as a multi-material component

2025-04-29

Stefan Brenner , Marcel Dickmann , Ricardo Helm +7 more

Abstract Linear particle accelerators (Linacs) are essential for numerous applications in industry, medicine, and research. However, their use is often constrained by high investment costs, which are largely driven by … Abstract Linear particle accelerators (Linacs) are essential for numerous applications in industry, medicine, and research. However, their use is often constrained by high investment costs, which are largely driven by conventional manufacturing methods. Studies have shown that additive manufacturing (AM) has the potential to significantly reduce these costs while simultaneously enhancing Linac performance. This study investigates this potential for the production of radio-frequency quadrupoles (RFQs), one of the most important Linacs for ion acceleration. For the first time, a multi-material RFQ prototype was fabricated using multi-material (MM) laser powder bed fusion (PBF-LB/M) AM, integrating the copper alloy CuCr1Zr for the internal cavity and tool steel (1.2709) for the outer shell in a single manufacturing step. The prototype’s design features six ConFlat® (CF) flanges for sealing without O-rings, highlighting the advantages of MM AM in simplifying assembly and enhancing functionality. Experimental evaluations included assessments of geometric precision, surface roughness, microstructural integrity, vacuum performance, resonance frequency (f R ), and quality factor (Q 0 ). The results demonstrated the successful application of MM PBF-LB/M for RFQ production, achieving a vacuum pressure below 8.3 ∙ 10 –8 mbar in the prototype. However, challenges in geometric precision and material transition zones necessitate further process optimization. This work underscores the potential of MM PBF-LB/M to address limitations in mono-material AM, particularly for Linac applications. Future developments, such as enabling pure copper processing and improving thermal and mechanical performance, could establish MM PBF-LB/M as a transformative technology for advanced Linac designs, paving the way for enhanced Linac applications.

Analysis of the typical characteristics of aperture coupling for aircraft under electromagnetic environments

2025-04-20

Jinling Geng , Guihao Bao , Lingcai Huang +1 more

How additive interference and phase fluctuations influence the performance of a synthetic aperture antenna on an arbitrary aircraft path

2025-04-15

Евгений Кимович Самаров , Irina Vladimirovna Evgrafova

BACKGROUND: Dedicated papers often study the influence of phase fluctuations of signals received by radar stations with a synthetic aperture antenna on the azimuth resolution and accuracy of stationary moving … BACKGROUND: Dedicated papers often study the influence of phase fluctuations of signals received by radar stations with a synthetic aperture antenna on the azimuth resolution and accuracy of stationary moving ground objects for arbitrary aircraft trajectories without additive interference. AIM: To determine how additive interference and phase fluctuations influence azimuth resolution and accuracy of a radar station with a synthetic aperture antenna during arbitrary movement of an aircraft and ground objects. MATERIALS AND METHODS: The article reviews and analyzes the influence of phase fluctuations and additive interference on the key parameters of a synthetic aperture antenna during arbitrary movement of an aircraft and ground objects. RESULTS: The article presents relationships to assess the resolution and accuracy of azimuth determination by a radar station with a synthetic aperture antenna under the influence of phase fluctuations of the reflected signal and additive interference during arbitrary movement of an aircraft and ground objects. CONCLUSIONS: It is shown that under the influence of additive interference, the expected value and dispersion of the object’s angular position and the output signal duration in the angular position depend on the ratio of the output performance of this noise and the reflected signal.

Unified Model and Survey on Modulation Schemes for Next-Generation Automotive Radar Systems

2025-04-10

Moritz Kahlert , Tai Fei , Wang Yu-ming +2 more

Commercial automotive radar systems for advanced driver assistance systems (ADASs) have relied on frequency-modulated continuous wave (FMCW) waveforms for years due to their low-cost hardware, simple signal processing, and established … Commercial automotive radar systems for advanced driver assistance systems (ADASs) have relied on frequency-modulated continuous wave (FMCW) waveforms for years due to their low-cost hardware, simple signal processing, and established academic and industrial expertise. However, FMCW systems face several challenges, including limited unambiguous velocity, restricted multiplexing of transmit signals, and susceptibility to interference. This work introduces a unified automotive radar signal model and reviews the alternative modulation schemes such as phase-coded frequency-modulated continuous wave (PC-FMCW), phase-modulated continuous wave (PMCW), orthogonal frequency-division multiplexing (OFDM), orthogonal chirp division multiplexing (OCDM), and orthogonal time frequency space (OTFS). These schemes are assessed against key technological and economic criteria and compared with FMCW, highlighting their respective strengths and limitations.

Compatibility Analysis Between Ldacs and Dme by Exploiting Gnu-Radio-Based Simulations and Laboratory Tests

2025-04-08

Siqi Huang , Kai Guo , Hugo Sok +1 more

High-precision measurement equipment for EMC antenna calibration

2025-04-03

M. S. Shkurkin

The article formulates the problems of antenna calibration used for testing for electromagnetic compatibility.It is noted that the apparatus and calibration methods of test antennas existing in the Russian Federation … The article formulates the problems of antenna calibration used for testing for electromagnetic compatibility.It is noted that the apparatus and calibration methods of test antennas existing in the Russian Federation do not allow for an effective achievement of EMC test goals, primarily due to high uncertainties of their antenna factor. To achieve the required accuracy of measurements of antenna characteristics and, as a result, electromagnetic compatibility parameters a High-precision measurement equipment for EMC antenna calibration are presented. The application of this equipment allows not only to carry out high-precision measurements of the characteristics of radiated industrial radio interference, but also to implement three classical methods of antenna measurements over a metal ground plane in a large semi-anechoic shielded chamber, as well as a method of measurements at close distances. Based on these methods, algorithms and methods for measuring the characteristics of antennas and antenna calibration test sites have been developed. The main results of the development are presented, including the results of experimental studies of the functionality and metrological characteristics of the measurement system using the example of precision resonant dipoles. The results obtained will be used to create the technical basis for a system to ensure the uniformity of measurements of the characteristics of antennas used for electromagnetic compatibility tests. The developed large polygonal semi-anechoic chamber can be considered as a reference test site of the Russian Federation and in the CIS countries, including during interlaboratory comparison tests.

The SABRE South technical design report executive summary

2025-04-01

E. L. Barberio , To. Baroncelli , Victoria U. Bashu +7 more

Abstract In this technical design report (TDR) executive summary we describe the SABRE South detector to be built at the Stawell Underground Physics Laboratory (SUPL). The SABRE South detector is … Abstract In this technical design report (TDR) executive summary we describe the SABRE South detector to be built at the Stawell Underground Physics Laboratory (SUPL). The SABRE South detector is designed to test the long-standing DAMA/LIBRA signal of an annually modulating rate consistent with dark matter by using the same target material. Located in the Southern Hemisphere, the detector is uniquely positioned to disentangle modulating seasonal effects. SABRE South uses seven ultra-high purity NaI(Tl) crystals (with a total target mass of either 35 kg or 50 kg), hermetically sealed in copper enclosures that are suspended within a liquid scintillator active veto. High quantum efficiency and low background Hamamatsu R11065 photomultiplier tubes are directly coupled to both ends of the crystal, and enclosed with the crystal in an oxygen free copper enclosure. The active veto system consists of 11.6 kL of linear alkylbenzene (LAB) doped with a mixture of fluorophores and contained in a steel vessel, which is instrumented with at least 18 Hamamatsu R5912 photomultipliers. The active veto tags key radiogenic backgrounds intrinsic to the crystals, such as 40 K, and is expected to suppress the total background by 27% in the 1–6 keV region of interest. In addition to the liquid scintillator veto, a muon veto is positioned above the detector shielding. This muon veto consists of eight EJ-200 scintillator modules, with Hamamatsu R13089 photomultipliers coupled to both ends. With an expected total background of 0.72 cpd/kg/keV, SABRE South can test the DAMA/LIBRA signal with 5 σ discovery or 3 σ exclusion after two years of data taking.

Guest Editorial Measurement Technologies for Emerging 5G and Beyond Channel Characterization and Antenna Systems

2025-04-01

Wei Fan , Tian Hong Loh , L. J. Foged +3 more

A data restoration method for spherical near-field antenna measurements based on inverse distance weighting interpolation

2025-04-01

Yuquan Yang , Yun-Fei Jia

Abstract In the process of spherical near-field measurements for antennas, incomplete near-field data acquisition due to obstructions in certain regions can significantly affect the accuracy of the antenna radiation pattern … Abstract In the process of spherical near-field measurements for antennas, incomplete near-field data acquisition due to obstructions in certain regions can significantly affect the accuracy of the antenna radiation pattern test results. To address the far-field pattern errors caused by missing data, an inverse distance weighting interpolation method is proposed to restore the missing near-field data before performing the near-to-far-field transformation, thereby reducing the impact of missing data on the far-field results. The far-field radiation pattern after data restoration shows a significant improvement compared to before restoration, with average error reductions of 2.6707 dB in the E-plane and 1.5108 dB in the H-plane. Additionally, the obtained far-field radiation pattern closely matches the simulated pattern, indicating that this method is effective in restoring missing near-field data.

Parametric Study of Asymmetric Propagation of Guided and Unguided EMIC Waves Near the Local Characteristic Frequencies

2025-04-01

Xiang Xu , Chen Zhou

Abstract Previous studies demonstrate that the propagation of the guided and unguided electromagnetic ion cyclotron (EMIC) waves near the local characteristic frequencies in a dipole field shows prominent asymmetry with … Abstract Previous studies demonstrate that the propagation of the guided and unguided electromagnetic ion cyclotron (EMIC) waves near the local characteristic frequencies in a dipole field shows prominent asymmetry with the wave vector pointing toward lower L shells (wave normal angle ) and higher L shells () at low magnetic latitudes () using representative cases. The and dependence of this asymmetric behavior and the role of magnetic gradients in this process are not clear. Using full‐wave simulations and ray theories, a parametric study is conducted to address these questions. We find that the refraction due to the magnetic gradient term can be quantified by (the variation of during the wavelength) primarily contributed by the product of the normalized derivative of the refractive index, the magnetic gradient and the unit vector perpendicular to . At low , the sign of generally remains constant and is large so that with keeps deviating from the field line while with has the potential to be close to the field line. This explains that the guided left‐handedly polarized (LHP) EMIC wave with may reverse its polarization and propagates to much lower altitudes if is within certain angular window. This also explains the for the maximum coupling efficiency from the unguided to guided LHP EMIC mode can be tens of degrees away from the field‐aligned direction. As increases, the asymmetry of and the propagation of EMIC waves near the local characteristic frequencies becomes smaller.

Combining Near-Field Over the Air (OTA) Measurements with Advanced Post-Processing Link Approach to Evaluate Specific Absorption Rate (SAR) for a Commercial Smartphone

2025-03-30

Shoaib Anwar , A. Lelievre , B. Frotte +4 more