Engineering › Aerospace Engineering

Advanced Antenna and Metasurface Technologies

Works Count: 45253

Wikipedia

Description

This cluster of papers focuses on the design, analysis, and application of metasurfaces, including frequency selective surfaces, reflectarrays, and artificial magnetic conductors, for antenna and radar systems. The research covers topics such as low-profile design, beam control, radar absorbers, and high impedance surfaces.

Keywords

Metasurfaces; Frequency Selective Surfaces; Reflectarrays; Antennas; Radar Absorbers; Artificial Magnetic Conductors; High Impedance Surfaces; Beam Control; Low-Profile Design; Electromagnetic Bandgap

The reflectarray antenna

1963-11-01

D. Berry , R. Malech , William A. Kennedy

A class of antennas that utilizes arrays of elementary antennas as reflecting surfaces has been investigated. An antenna of this type is here called a Reflectarray. It has been found … A class of antennas that utilizes arrays of elementary antennas as reflecting surfaces has been investigated. An antenna of this type is here called a Reflectarray. It has been found that the Reflectarray combines much of the simplicity of the reflector-type antenna with the performance versatility of the array type. The reflecting surfaces employed in these antennas are characterized by a surface impedance that can be synthesized to produce a variety of radiation patterns. The equations of the surface impedance as a function of the desired reflected phase front is derived for the lossless case and methods of realizing this surface impedance are presented. Experimental results of a waveguide array type Reflectarray are given including pencil beam, broad beam and scanning modes. Data on the effects of specific phase errors are presented.

Reflection properties of the Salisbury screen

1988-01-01

Ronald L. Fante , M.T. McCormack

The reflection properties of multiple electric/magnetic Salisbury screens have been studied. Analytical formulae are developed for the maximally flat design of two- and three-screen planar stackups that have taken into … The reflection properties of multiple electric/magnetic Salisbury screens have been studied. Analytical formulae are developed for the maximally flat design of two- and three-screen planar stackups that have taken into account appropriate values for the spacer materials used to separate the screens. The effect of curvature has also been assessed. It is shown that relatively large reductions in specular reflection are possible over sizeable bandwidths using relatively few Salisbury screens. Furthermore, these reductions are not completely destroyed if the incident wave is not normal to the surface, if the surface is curved or if there are errors in fabrication of the screen.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Linear-to-Circular Polarization Conversion Using Metasurface

2013-06-11

Hai‐Liang Zhu , S. W. Cheung , Kwok L. Chung +1 more

A metasurface (MS) used to convert the linearly polarized (LP) signal from a source antenna into a circularly polarized (CP) signal is proposed and studied. The MS consists of 16 … A metasurface (MS) used to convert the linearly polarized (LP) signal from a source antenna into a circularly polarized (CP) signal is proposed and studied. The MS consists of 16 unit cells arranged in a 4 × 4 layout. Each unit cell is a rectangular loop with a diagonal microstrip. By placing close to a source antenna, the MS converts the LP signal generated from the source antenna into a CP signal. Two source antennas (patch and slot antennas) are used for studies. The source antenna together with the MS is here called a MS antenna. A total of four low-profile MS antennas operating at the frequency of about 2.45 GHz are designed using computer simulation. For verification of simulation results, the MS antennas are fabricated and measured. Simulated and measured results show good agreements. Results show that the MS antennas have substantially better performances, in terms of gain, return-loss bandwidth (RLBW), axial-ratio bandwidth (ARBW) and radiation pattern, than the source antennas. Moreover, the ARBW of the MS antennas is mainly determined by the MS.

Enhanced patch-antenna performance by suppressing surface waves using photonic-bandgap substrates

1999-01-01

R. Gonzalo , P. de Maagt , M. Sorolla

The microstrip patch antenna is a low-profile robust planar structure. A wide range of radiation patterns can be achieved with this type of antenna and, due to the ease of … The microstrip patch antenna is a low-profile robust planar structure. A wide range of radiation patterns can be achieved with this type of antenna and, due to the ease of manufacture, is inexpensive compared with other types of antennas. However, patch-antenna designs have some limitations such as restricted bandwidth of operation, low gain, and a potential decrease in radiation efficiency due to surface-wave losses. In this paper, a photonic-bandgap (PBG) substrate for patch antennas is proposed, which minimizes the surface-wave effects. In order to verify the performance of this kind of substrate, a configuration with a thick substrate is analyzed. The PBG patch antenna shows significantly reduced levels of surface modes compared to conventional patch antennas, thus improving the gain and far-field radiation pattern.

Analysis of a reflectarray antenna using microstrip patches of variable size

1993-01-01

D.M. Pozar , T.A. Metzler

Microstrip reflectarrays tyically use tuning stubs on each element to adjust the phase of the reflected field. This Letter describes a new approach in which the need for tuning stubs … Microstrip reflectarrays tyically use tuning stubs on each element to adjust the phase of the reflected field. This Letter describes a new approach in which the need for tuning stubs is eliminated and phase control is achieved simply by adjusting the resonant length of the patch elements. The advantages of this approach are described, as are a full-wave analysis technique for computing the phase of the reflected field as a function of patch size and a design curve giving the change in patch size for a desired reflected field phase shift.

Diffraction-free beams

1987-04-13

J. Durnin , Joseph J. Miceli , J. H. Eberly

It was recently predicted that nondiffracting beams, with beam spots as small as a few wavelengths, can exist and propagate in free space. We report the first experimental investigation of … It was recently predicted that nondiffracting beams, with beam spots as small as a few wavelengths, can exist and propagate in free space. We report the first experimental investigation of these beams.

Checkerboard EBG Surfaces for Wideband Radar Cross Section Reduction

2015-03-18

Wengang Chen , Constantine A. Balanis , Craig R. Birtcher

Electromagnetic band-gap (EBG) structures have noteworthy electromagnetic characteristics that include their reflection phase variations with frequency. This paper applies this unique reflection phase property to alter the direction of the … Electromagnetic band-gap (EBG) structures have noteworthy electromagnetic characteristics that include their reflection phase variations with frequency. This paper applies this unique reflection phase property to alter the direction of the fields scattered by a radar target to reduce its radar cross section (RCS). This redirecting of the scattered fields occurs when a surface is covered with a checkerboard of alternating EBG structures, and results in a wider frequency band RCS reduction. RCS reduction compared to a PEC surface of 10 dB can be realized over 60% frequency bandwidth. Simulations of monostatic and bistatic RCSs of two dual EBG checkerboard surfaces, square and hexagonal, are compared with those of equal-sized PEC ground planes. The simulated monostatic RCS is also compared with measurements. Both TE z and TM z polarizations for oblique incidence are considered. Excellent agreement is obtained between simulated and measured patterns, for both the square and the hexagonal EBG checkerboard surfaces. An approximate analytical expression is provided as a guideline for a 10-dB RCS reduction of a dual EBG checkerboard surface compared to that of a PEC.

Conformal Printing of Electrically Small Antennas on Three‐Dimensional Surfaces

2011-01-19

Jacob J. Adams , Eric B. Duoss , Thomas F. Malkowski +5 more

Conformal printing of electrically small antennas onto the convex and concave surfaces of hemispherical glass substrates is demonstrated. Their bandwidth approaches the fundamental limit for their size, offering nearly an … Conformal printing of electrically small antennas onto the convex and concave surfaces of hemispherical glass substrates is demonstrated. Their bandwidth approaches the fundamental limit for their size, offering nearly an order of magnitude improvement over rudimentary monopole designs. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Robust method to retrieve the constitutive effective parameters of metamaterials

2004-07-26

Xudong Chen , Tomasz M. Grzegorczyk , Bae‐Ian Wu +2 more

We propose an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters. Improvements over existing methods include … We propose an improved method to retrieve the effective constitutive parameters (permittivity and permeability) of a slab of metamaterial from the measurement of S parameters. Improvements over existing methods include the determination of the first boundary and the thickness of the effective slab, the selection of the correct sign of effective impedance, and a mathematical method to choose the correct branch of the real part of the refractive index. The sensitivity of the effective constitutive parameters to the accuracy of the S parameters is also discussed. The method has been applied to various metamaterials and the successful retrieval results prove its effectiveness and robustness.

A Transmission Line Taper of Improved Design

1956-01-01

R. W. Klopfenstein

The theory of the design of optimal cascaded transformer arrangements can be extended to the design of continuous transmission-line tapers. Convenient relationships have been obtained from which the characteristic impedance … The theory of the design of optimal cascaded transformer arrangements can be extended to the design of continuous transmission-line tapers. Convenient relationships have been obtained from which the characteristic impedance contour for an optimal transmission-line taper can be found. The performance of the Dolph-Tchebycheff transmission-line taper treated here is optimum in the sense that it has minim reflection coefficient magnitude in the pass band for a specified length of taper, and, likewise, for a specified maximum magnitude reflection coefficient in the pass band, the Dolph-Tchebycheff taper has minimum length. A sample design has been carried out for the purposes of illustration, and its performance has been compared with that of other tapers. In addition, a table of values of a transcendental function used in the design of these tapers is given.

Equivalent circuit model for arrays of square loops

1982-04-01

R.J. Langley , E.A. Parker

Square-loop arrays are of interest as frequency selective surfaces. Experimental results for these arrays are presented, and a simple equivalent circuit model is described which predicts the plane-wave transmission characteristics … Square-loop arrays are of interest as frequency selective surfaces. Experimental results for these arrays are presented, and a simple equivalent circuit model is described which predicts the plane-wave transmission characteristics for normal incidence. These elements are a new member of the group of arrays for which simple equivalent circuits are available.

Techniques for analyzing frequency selective surfaces-a review

1988-12-01

R. Mittra , Chi Hou Chan , T. Cwik

A number of representative techniques for analyzing frequency-selective surfaces (FSSs), which comprise periodic arrays of patches or apertures in a conducting screen and find important applications as filters in microwaves … A number of representative techniques for analyzing frequency-selective surfaces (FSSs), which comprise periodic arrays of patches or apertures in a conducting screen and find important applications as filters in microwaves and optics, are discussed. The basic properties of the FSSs are reviewed and several different approaches to predicting their frequency-response characteristics are described. Some recent developments in the treatment of truncated, curved, and doubly periodic screens are mentioned and representative experimental results are included.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

High gain planar antenna using optimised partially reflective surfaces

2001-01-01

Alexandros Feresidis , J.C. Vardaxoglou

A high gain planar antenna has been investigated, using an optimised partially reflecting surface (PRS) placed in front of a waveguide aperture in a ground plane. The antenna performance is … A high gain planar antenna has been investigated, using an optimised partially reflecting surface (PRS) placed in front of a waveguide aperture in a ground plane. The antenna performance is initially related to the reflection characteristics of the PRS array following an approximate analysis. The array geometry is optimised using an analytical formula. The optimisation results are verified using a full wave model taking into account the edge effects. The array size for maximum antenna efficiency has also been investigated.

Magneto-Dielectrics in Electromagnetics: Concept and Applications

2004-06-01

Hossein Mosallaei , Kamal Sarabandi

In this paper, the unique features of periodic magneto-dielectric meta-materials in electromagnetics are addressed. These materials, which are arranged in periodic configurations, are applied for the design of novel EM … In this paper, the unique features of periodic magneto-dielectric meta-materials in electromagnetics are addressed. These materials, which are arranged in periodic configurations, are applied for the design of novel EM structures with applications in the VHF-UHF bands. The utility of these materials is demonstrated by considering two challenging problems, namely, design of miniaturized electromagnetic band-gap (EBG) structures and antennas in the VHF-UHF bands. A woodpile EBG made up of magneto-dielectric material is proposed. It is shown that the magneto-dielectric woodpile not only exhibits band-gap rejection values much higher than the ordinary dielectric woodpile, but also for the same physical dimensions it shows a rejection band at a much lower frequency. The higher rejection is a result of higher effective impedance contrasts between consecutive layers of the magneto-dielectric woodpile structure. Composite magneto-dielectrics are also shown to provide certain advantages when used as substrates for planar antennas. These substrates are used to miniaturize antennas while maintaining a relatively high bandwidth and efficiency. An artificial anisotropic meta-substrate having /spl mu//sub r/>/spl epsiv//sub r/, made up of layered magneto-dielectric and dielectric materials is designed to maximize the bandwidth of a miniaturized patch antenna. Analytical and numerical approaches, based on the anisotropic effective medium theory (AEMT) and the finite-difference time-domain (FDTD) technique, are applied to carry out the analyzes and fully characterize the performance of finite and infinite periodic magneto-dielectric meta-materials integrated into the EBG and antenna designs.

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Design, fabrication, and testing of double negative metamaterials

2003-07-01

Richard W. Ziolkowski

The design, fabrication, and testing of several metamaterials that exhibit double negative (DNG) medium properties at X band frequencies are reported. DNG media are materials in which the permittivity and … The design, fabrication, and testing of several metamaterials that exhibit double negative (DNG) medium properties at X band frequencies are reported. DNG media are materials in which the permittivity and permeability are both negative. Simulation and experimental results are given that demonstrate the realization of DNG metamaterials matched to free-space. The extraction of the effective permittivity and permeability for these metamaterials from reflection and transmission data at normal incidence is treated. It is shown that the metamaterials studied exhibit DNG properties in the frequency range of interest.

Antenna Miniaturization and Bandwidth Enhancement Using a Reactive Impedance Substrate

2004-09-01

Hossein Mosallaei , Kamal Sarabandi

The concept of a novel reactive impedance surface (RIS) as a substrate for planar antennas, that can miniaturize the size and significantly enhance both the bandwidth and the radiation characteristics … The concept of a novel reactive impedance surface (RIS) as a substrate for planar antennas, that can miniaturize the size and significantly enhance both the bandwidth and the radiation characteristics of an antenna is introduced. Using the exact image formulation for the fields of elementary sources above impedance surfaces, it is shown that a purely reactive impedance plane with a specific surface reactance can minimize the interaction between the elementary source and its image in the RIS substrate. An RIS can be tuned anywhere between perfectly electric and magnetic conductor (PEC and PMC) surfaces offering a property to achieve the optimal bandwidth and miniaturization factor. It is demonstrated that RIS can provide performance superior to PMC when used as substrate for antennas. The RIS substrate is designed utilizing two-dimensional periodic printed metallic patches on a metal-backed high dielectric material. A simplified circuit model describing the physical phenomenon of the periodic surface is developed for simple analysis and design of the RIS substrate. Also a finite-difference time-domain (FDTD) full-wave analysis in conjunction with periodic boundary conditions and perfectly matched layer walls is applied to provide comprehensive study and analysis of complex antennas on such substrates. Examples of different planar antennas including dipole and patch antennas on RIS are considered, and their characteristics are compared with those obtained from the same antennas over PEC and PMC. The simulations compare very well with measured results obtained from a prototype /spl lambda//10 miniaturized patch antenna fabricated on an RIS substrate. This antenna shows measured relative bandwidth, gain, and radiation efficiency of BW=6.7, G=4.5 dBi, and e/sub r/=90, respectively, which constitutes the highest bandwidth, gain, and efficiency for such a small size thin planar antenna.

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Microstrip antennas integrated with electromagnetic band-gap (EBG) structures: a low mutual coupling design for array applications

2003-10-01

Fan Yang , Yahya Rahmat‐Samii

Utilization of electromagnetic band-gap (EBG) structures is becoming attractive in the electromagnetic and antenna community. In this paper, a mushroom-like EBG structure is analyzed using the finite-difference time-domain (FDTD) method. … Utilization of electromagnetic band-gap (EBG) structures is becoming attractive in the electromagnetic and antenna community. In this paper, a mushroom-like EBG structure is analyzed using the finite-difference time-domain (FDTD) method. Its band-gap feature of surface-wave suppression is demonstrated by exhibiting the near field distributions of the electromagnetic waves. The mutual coupling of microstrip antennas is parametrically investigated, including both the E and H coupling directions, different substrate thickness, and various dielectric constants. It is observed that the E-plane coupled microstrip antenna array on a thick and high permittivity substrate has a strong mutual coupling due to the pronounced surface waves. Therefore, an EBG structure is inserted between array elements to reduce the mutual coupling. This idea has been verified by both the FDTD simulations and experimental results. As a result, a significant 8 dB mutual coupling reduction is noticed from the measurements.

Design of two-layer printed reflectarrays using patches of variable size

2001-01-01

José A. Encinar

A multilayer reflectarray composed of two stacked arrays with rectangular patches of variable size is demonstrated. A progressive phase distribution on the reflector surface is achieved by adjusting the dimensions … A multilayer reflectarray composed of two stacked arrays with rectangular patches of variable size is demonstrated. A progressive phase distribution on the reflector surface is achieved by adjusting the dimensions of the patches. The phase of the reflection coefficient at each element is computed by the method of moments in the spectral domain, assuming local periodicity. A technique is presented for the design of dual polarization reflectarrays that yields all the dimensions for the photo-etching mask. A prototype has been design, built and measured, and a superior bandwidth performance has been verified, compared to conventional single layer reflectarrays.

Artificial magnetic conductor surfaces and their application to low-profile high-gain planar antennas

2005-01-01

Alexandros Feresidis , George Goussetis , Shenhong Wang +1 more

Planar periodic metallic arrays behave as artificial magnetic conductor (AMC) surfaces when placed on a grounded dielectric substrate and they introduce a zero degrees reflection phase shift to incident waves. … Planar periodic metallic arrays behave as artificial magnetic conductor (AMC) surfaces when placed on a grounded dielectric substrate and they introduce a zero degrees reflection phase shift to incident waves. In this paper the AMC operation of single-layer arrays without vias is studied using a resonant cavity model and a new application to high-gain printed antennas is presented. A ray analysis is employed in order to give physical insight into the performance of AMCs and derive design guidelines. The bandwidth and center frequency of AMC surfaces are investigated using full-wave analysis and the qualitative predictions of the ray model are validated. Planar AMC surfaces are used for the first time as the ground plane in a high-gain microstrip patch antenna with a partially reflective surface as superstrate. A significant reduction of the antenna profile is achieved. A ray theory approach is employed in order to describe the functioning of the antenna and to predict the existence of quarter wavelength resonant cavities.

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A Frequency Selective Radome With Wideband Absorbing Properties

2012-04-12

Filippo Costa , Agostino Monorchio

A frequency selective radome is presented, acting as a pass band filter at a given frequency band, while behaving as an absorber above the transmission band. The pass band behavior … A frequency selective radome is presented, acting as a pass band filter at a given frequency band, while behaving as an absorber above the transmission band. The pass band behavior is obtained by a metallic FSS realized through a compact interdigitated Jerusalem cross element characterized by a very large rejection band. The metallic FSS is used as the ground plane of a thin wideband absorber based on resistive high-impedance surfaces within the total reflection band. The outer absorber reduces the signature of the antenna system when the radome is illuminated by out of band signals. The resistive FSS which comprises the absorber is designed so to minimize losses within the transmitting band of the radome. The composite structure is thoroughly analyzed by an efficient equivalent circuit approach and by full-wave numerical simulations.

Design of lightweight, broad-band microwave absorbers using genetic algorithms

1993-01-01

Eric Michielssen , J.M. Sajer , S. Ranji Ranjithan +1 more

A procedure for synthesizing multilayered radar absorbing coatings is presented. Given a predefined set of N/sub m/ available materials with frequency-dependent permittivities in /sub i/(f) and permeabilities mu /sub i/(f) … A procedure for synthesizing multilayered radar absorbing coatings is presented. Given a predefined set of N/sub m/ available materials with frequency-dependent permittivities in /sub i/(f) and permeabilities mu /sub i/(f) (i=1,. . ., N/sub m/), the technique determines simultaneously the optimal material choice for each layer and its thickness. This optimal choice results in a screen which maximally absorbs TM and TE incident plane waves for a prescribed range of frequencies (f/sub 1/,f/sub 2/,. . ., f/sub N/f) and incident angles ( theta /sub 1/, theta /sub 2/,. . ., theta /sub N theta /). The synthesis technique is based on a genetic algorithm. The technique automatically places an upper bound on the total thickness of the coating, as well as the number of layers contained in it, which greatly simplifies manufacturing. In addition, the thickness or surface mass of the coating can be minimized simultaneously with the reflection coefficient. The algorithm was successfully applied to the synthesis of wideband absorbing coatings in the frequency ranges of 0.2-2 GHz and 2-8 GHz.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Characterization of Liquid Crystal Polymer (LCP) Material and Transmission Lines on LCP Substrates From 30 to 110 GHz

2004-04-01

D.C. Thompson , O. Tantot , H. Jallageas +3 more

Liquid crystal polymer (LCP) is a material that has gained attention as a potential high-performance microwave substrate and packaging material. This investigation uses several methods to determine the electrical properties … Liquid crystal polymer (LCP) is a material that has gained attention as a potential high-performance microwave substrate and packaging material. This investigation uses several methods to determine the electrical properties of LCP for millimeter-wave frequencies. Microstrip ring resonators and cavity resonators are measured in order to characterize the dielectric constant (/spl epsi//sub r/) and loss tangent (tan/spl delta/) of LCP above 30 GHz. The measured dielectric constant is shown to be steady near 3.16, and the loss tangent stays below 0.0049. In addition, various transmission lines are fabricated on different LCP substrate thicknesses and the loss characteristics are given in decibels per centimeter from 2 to 110 GHz. Peak transmission-line losses at 110 GHz vary between 0.88-2.55 dB/cm, depending on the line type and geometry. These results show, for the first time, that LCP has excellent dielectric properties for applications extending through millimeter-wave frequencies.

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Scalar and Tensor Holographic Artificial Impedance Surfaces

2010-07-08

Bryan H. Fong , J.S. Colburn , John J. Ottusch +2 more

We have developed a method for controlling electromagnetic surface wave propagation and radiation from complex metallic shapes. The object is covered with an artificial impedance surface that is implemented as … We have developed a method for controlling electromagnetic surface wave propagation and radiation from complex metallic shapes. The object is covered with an artificial impedance surface that is implemented as an array of sub-wavelength metallic patches on a grounded dielectric substrate. We pattern the effective impedance over the surface by varying the size of the metallic patches. Using a holographic technique, we design the surface to scatter a known input wave into a desired output wave. Furthermore, by varying the shape of the patches we can create anisotropic surfaces with tensor impedance properties that provide control over polarization. As an example, we demonstrate a tensor impedance surface that produces circularly polarized radiation from a linearly polarized source.

An idea for thin subwavelength cavity resonators using metamaterials with negative permittivity and permeability

2002-01-01

Nader Engheta

We present and analyze theoretically some ideas for thin one-dimensional (1D) cavity resonators in which a combination of a conventional dielectric material and a metamaterial possessing negative permittivity and permeability … We present and analyze theoretically some ideas for thin one-dimensional (1D) cavity resonators in which a combination of a conventional dielectric material and a metamaterial possessing negative permittivity and permeability has been inserted. It is shown that a slab of metamaterial with negative permittivity and permeability can act as a phase compensator/conjugator and, thus, by combining such a slab with another slab made of a conventional dielectric material, one can, in principle, have a 1D cavity resonator whose dispersion relation may not depend on the sum of thicknesses of the interior materials filling this cavity, but instead it depends on the ratio of these thicknesses. In other words, one can, in principle, conceptualize a 1D cavity resonator with the total thickness far less than the conventional /spl lambda//2. Mathematical steps and physical intuitions relevant to this problem are presented.

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Aperture-coupled patch antenna on UC-PBG substrate

1999-01-01

R. Coccioli , Fei-Ran Yang , Kuang-Ping Ma +1 more

The recently developed uniplanar compact photonic bandgap (UC-PBG) substrate is successfully used to reduce surface-wave losses for an aperture-coupled fed patch antenna on a thick high dielectric-constant substrate. The surface-wave … The recently developed uniplanar compact photonic bandgap (UC-PBG) substrate is successfully used to reduce surface-wave losses for an aperture-coupled fed patch antenna on a thick high dielectric-constant substrate. The surface-wave dispersion diagram of the UC-PBG substrate has been numerically computed for two different substrate thickness (25 and 50 mil) and found to have a complete stopband in the frequency range of 10.9-13.5 and 11.4-12.8 GHz, respectively. The thicker substrate is then used to enhance broadside gain of a patch antenna working in the stopband at 12 GHz. Computed results and measured data show that, due to effective surface-wave suppression, the antenna mounted on the UC-PBG substrate has over 3-dB higher gain in the broadside direction than the same antenna etched on a grounded dielectric slab with same thickness and dielectric constant. Cross-polarization level remains 13 dB down the co-polar component level for both E- and H-planes.

Reconfigurable Reflectarrays and Array Lenses for Dynamic Antenna Beam Control: A Review

2013-11-19

Sean V. Hum , Julien Perruisseau‐Carrier

Advances in reflectarrays and array lenses with electronic beam-forming capabilities are enabling a host of new possibilities for these high-performance, low-cost antenna architectures. This paper reviews enabling technologies and topologies … Advances in reflectarrays and array lenses with electronic beam-forming capabilities are enabling a host of new possibilities for these high-performance, low-cost antenna architectures. This paper reviews enabling technologies and topologies of reconfigurable reflectarray and array lens designs, and surveys a range of experimental implementations and achievements that have been made in this area in recent years. The paper describes the fundamental design approaches employed in realizing reconfigurable designs, and explores advanced capabilities of these nascent architectures, such as multi-band operation, polarization manipulation, frequency agility, and amplification. Finally, the paper concludes by discussing future challenges and possibilities for these antennas.

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Averaged transition conditions for electromagnetic fields at a metafilm

2003-10-01

Edward F. Kuester , Moustafa Mohamed , M. Piket-May +1 more

This paper derives generalized sheet transition conditions (GSTCs) for the average electromagnetic fields across a surface distribution of electrically small scatterers characterized by electric and magnetic polarization densities. We call … This paper derives generalized sheet transition conditions (GSTCs) for the average electromagnetic fields across a surface distribution of electrically small scatterers characterized by electric and magnetic polarization densities. We call such an arrangement of scatterers a metafilm-the two-dimensional (2-D) equivalent of a metamaterial. The derivation is based on a replacement of the discrete distribution of scatterers by a continuous one, resulting in a continuous distribution of electric and magnetic polarization densities in the surface. This is done in a manner analogous to the Clausius-Mossotti-Lorenz-Lorentz procedure for determining the dielectric constant of a volume distribution of small scatterers. The result contains as special cases many particular ones found throughout the literature. The GSTCs are expected to have wide application to the design and analysis of antennas, reflectors, and other devices where controllable scatterers are used to form a "smart" surface.

Analysis and Design of Ultra Thin Electromagnetic Absorbers Comprising Resistively Loaded High Impedance Surfaces

2010-03-02

Filippo Costa , Agostino Monorchio , Giuliano Manara

High-Impedance Surfaces (HIS) comprising lossy Frequency Selective Surfaces (FSS) are employed to design thin electromagnetic absorbers. The structure, despite its typical resonant behavior, is able to perform a very wideband … High-Impedance Surfaces (HIS) comprising lossy Frequency Selective Surfaces (FSS) are employed to design thin electromagnetic absorbers. The structure, despite its typical resonant behavior, is able to perform a very wideband absorption in a reduced thickness. Losses in the frequency selective surface are introduced by printing the periodic pattern through resistive inks and hence avoiding the typical soldering of a large number of lumped resistors. The effect of the surface resistance of the FSS and dielectric substrate characteristics on the input impedance of the absorber is discussed by means of a circuital model. It is shown that the optimum value of surface resistance is affected both by substrate parameters (thickness and permittivity) and by FSS element shape. The equivalent circuit model is then used to introduce the working principles of the narrowband and the wideband absorbing structure and to derive the best-suited element for wideband absorption. Finally, the experimental validation of the presented structures is presented.

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A Frequency Selective Surface With Miniaturized Elements

2007-05-01

Kamal Sarabandi , Nader Behdad

We demonstrate a new class of bandpass frequency selective surface (FSS), the building block of which, unlike the traditional FSSs, makes use of resonant dipole and slot structures that have … We demonstrate a new class of bandpass frequency selective surface (FSS), the building block of which, unlike the traditional FSSs, makes use of resonant dipole and slot structures that have dimensions much smaller than the operating wavelength. This design allows localization of bandpass characteristics to within a small area on the surface which in turn facilitates flexible spatial filtering for an arbitrary wave phasefront. The proposed FSS is made up of periodic array of metallic patches separated by thin air-gaps backed by a wire mesh having the same periodicity (Ltlambda). The array of metallic patches constitute a capacitive surface and the wire mesh a coupled inductive surface, which together act as a resonant structure in the path of an incident plane wave. Like traditional FSSs, the capacitive and inductive surfaces of the proposed FSS can easily be fabricated using printed circuit technology on both sides of microwave substrates. It is shown that by cascading such bandpass surfaces in a proper fashion, any arbitrary multipole filter or non-commensurate multiband response can be obtained. The frequency response of the proposed miniaturized-element frequency selective surface (MEFSS) is demonstrated for various incident angles and it is shown that one-pole designs are less sensitive than two-pole designs to the angle of incidence. Dual band designs are also possible based on two-pole designs, but are more sensitive to incident angle than single band designs because of their larger (in terms of wavelengths) spacing. Prototypes of single-pole and dual-pole MEFSSs are fabricated and tested in a waveguide environment at X-band frequencies and excellent agreements between the measured and simulated results are demonstrated

Two-dimensional beam steering using an electrically tunable impedance surface

2003-10-01

Daniel F. Sievenpiper , James H. Schaffner , H.J. Song +2 more

By covering a metal ground plane with a periodic surface texture, we can alter its electromagnetic properties. The impedance of this metasurface can be modeled as a parallel resonant circuit, … By covering a metal ground plane with a periodic surface texture, we can alter its electromagnetic properties. The impedance of this metasurface can be modeled as a parallel resonant circuit, with sheet inductance L, and sheet capacitance C. The reflection phase varies with frequency from +/spl pi/ to -/spl pi/, and crosses through 0 at the LC resonance frequency, where the surface behaves as an artificial magnetic conductor. By incorporating varactor diodes into the texture, we have built a tunable impedance surface, in which an applied bias voltage controls the resonance frequency, and the reflection phase. We can program the surface to create a tunable phase gradient, which can electronically steer a reflected beam over +/- 40/spl deg/ in two dimensions, for both polarizations. We have also found that this type of resonant surface texture can provide greater bandwidth than conventional reflectarray structures. This new electronically steerable reflector offers a low-cost alternative to a conventional phased array.

Partially reflecting sheet arrays

1956-10-01

G. v. Trentini

Multiple reflections of electromagnetic waves between two planes are studied, and the increase in directivity that results by placing a partially reflecting sheet in front of an antenna with a … Multiple reflections of electromagnetic waves between two planes are studied, and the increase in directivity that results by placing a partially reflecting sheet in front of an antenna with a reflecting screen is investigated at a wavelength of 3.2 cm. The construction and performance of various models of such arrays is discussed. Thus, for example, a "reflex-cavity antenna" with an outer diameter of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.88 \lambda</tex> and an over-all length of only <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.65 \lambda</tex> is described which has half-power beamwidths of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">34\deg</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">41\deg</tex> in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</tex> planes, respectively, and a gain of approximately 14 db. It is shown that larger systems produce considerably greater directivity but that their efficiency is poor.

Design of millimeter wave microstrip reflectarrays

1997-02-01

D.M. Pozar , S.D. Targonski , Harry D. Syrigos

This paper discusses the theoretical modeling and practical design of millimeter wave reflectarrays using microstrip patch elements of variable size. A full-wave treatment of plane wave reflection from a uniform … This paper discusses the theoretical modeling and practical design of millimeter wave reflectarrays using microstrip patch elements of variable size. A full-wave treatment of plane wave reflection from a uniform infinite array of microstrip patches is described and used to generate the required patch-design data and to calculate the radiation patterns of the reflectarray. The critical parameters of millimeter wave reflectarray design, such as aperture efficiency, phase errors, losses, and bandwidth are also discussed. Several reflectarray feeding techniques are described, and measurements from four reflectarray design examples at 28 and 77 GHz are presented.

Thin AMC Structure for Radar Cross-Section Reduction

2007-12-01

M. Paquay , Juan Carlos Iriarte , Iñigo Ederra +2 more

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A thin artificial magnetic conductor (AMC) structure is designed and breadboarded for radar cross-section (RCS) Reduction applications. The design presented in this paper shows the advantage of … <para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A thin artificial magnetic conductor (AMC) structure is designed and breadboarded for radar cross-section (RCS) Reduction applications. The design presented in this paper shows the advantage of geometrical simplicity while simultaneously reducing the overall thickness (for the current design <formula formulatype="inline"><tex>$\lambda/16$</tex></formula>). The design is very pragmatic and is based on a combination of AMC and perfect electric conductor (PEC) cells in a chessboard like configuration. An array of Sievenpiper's mushrooms constitutes the AMC part, while the PEC part is formed by full metallic patches. Around the operational frequency of the AMC-elements, the reflection of the AMC and PEC have opposite phase, so for any normal incident plane wave the reflections cancel out, thus reducing the RCS. The same applies to specular reflections for off-normal incidence angles. A simple basic model has been implemented in order to verify the behavior of this structure, while Ansoft-HFSS software has been used to provide a more thorough analysis. Both bistatic and monostatic measurements have been performed to validate the approach. </para>

High-impedance electromagnetic surfaces with a forbidden frequency band

1999-01-01

Daniel F. Sievenpiper , Lijun Zhang , R.F.J. Broas +2 more

A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it … A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.

A novel 1-D periodic defected ground structure for planar circuits

2000-04-01

Chul-Soo Kim , Jun‐Seok Park , Dal Ahn +1 more

A new one-dimensional (1-D) defected ground unit lattice is proposed in order to improve the effective inductance. Increasing the effective inductance makes it easy to control the cutoff frequency characteristics. … A new one-dimensional (1-D) defected ground unit lattice is proposed in order to improve the effective inductance. Increasing the effective inductance makes it easy to control the cutoff frequency characteristics. The proposed periodic defected ground structure (DGS) provides the excellent cutoff and stopband characteristics. In order to show the improved the effective inductance, three DGS circuits were fabricated with identical periodic and different dimensions. Measurements on the fabricated DGS circuits show that the cutoff and stopband center frequency characteristics depend on the physical dimension of the proposed DGS unit lattice,.

A Ka-band microstrip reflectarray with elements having variable rotation angles

1998-05-01

J.C. Huang , Ronald J. Pogorzelski

This paper demonstrates a novel means of achieving cophasal far-field radiation for a circularly polarized microstrip reflectarray with elements having variable rotation angles. Two Ka-band half-meter microstrip reflectarrays have been … This paper demonstrates a novel means of achieving cophasal far-field radiation for a circularly polarized microstrip reflectarray with elements having variable rotation angles. Two Ka-band half-meter microstrip reflectarrays have been fabricated and tested. Both are believed to be the electrically largest reflectarrays ever developed using microstrip patches. One, a conventional design, has identical square patches with variable-length microstrip phase-delay lines attached. The other has identical square patches with identical microstrip phase-delay lines but different element rotation angles. Both antennas demonstrated excellent performance with more than 55% aperture efficiencies, but the one with variable rotation angles resulted in better overall performance. A brief mathematical analysis is presented to validate this "rotational element" approach. With this approach, a means of scanning the main beam of the reflectarray over a wide angular region without any RF beamformer by using miniature or micromachined motors is viable.

Spectral Domain Immitance Approach for Dispersion Characteristics of Generalized Printed Transmission Lines

1980-07-01

T. Itoh

A simple method for formulating the dyadic Green's functions in the spectral domain is presented for generalized printed transmission Iines which contain several dielectric layers and conductors appearing at several … A simple method for formulating the dyadic Green's functions in the spectral domain is presented for generalized printed transmission Iines which contain several dielectric layers and conductors appearing at several dielectric interfaces. The method is based on the transverse equivalent transmission line for a spectral wave and on a simple coordinate transformation. This formulation process is so simple that often it is accomplished almost by inspection of the physical cross-sectional structure of the transmission line. The method is applied to a new versatile transmission line, a microstrip-slot Iine, and some numerical results are presented.

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Reflection phase characterizations of the EBG ground plane for low profile wire antenna applications

2003-10-01

Fan Yang , Yahya Rahmat‐Samii

Mushroom-like electromagnetic band-gap (EBG) structures exhibit unique electromagnetic properties that have led to a wide range of electromagnetic device applications. This paper focuses on the reflection phase feature of EBG … Mushroom-like electromagnetic band-gap (EBG) structures exhibit unique electromagnetic properties that have led to a wide range of electromagnetic device applications. This paper focuses on the reflection phase feature of EBG surfaces: when plane waves normally illuminate an EBG structure, the phase of the reflected field changes continuously from 180/spl deg/ to -180/spl deg/ versus frequency. One important application of this feature is that one can replace a conventional perfect electric conductor (PEC) ground plane with an EBG ground plane for a low profile wire antenna design. For this design, the operational frequency band of an EBG structure is defined as the frequency region within which a low profile wire antenna radiates efficiently, namely, having a good return loss and radiation patterns. The operational frequency band is the overlap of the input-match frequency band and the surface-wave frequency bandgap. It is revealed that the reflection phase curve can be used to identify the input-match frequency band inside of which a low profile wire antenna exhibits a good return loss. The surface-wave frequency bandgap of the EBG surface that helps improve radiation patterns is very close to its input-match frequency band, resulting in an effective operational frequency band. In contrast, a thin grounded slab cannot work efficiently as a ground plane for low profile wire antennas because its surface-wave frequency bandgap and input-match frequency band do not overlap. Parametric studies have been performed to obtain design guidelines for EBG ground planes. Two novel EBG ground planes with interesting electromagnetic features are also presented. The rectangular patch EBG ground plane has a polarization dependent reflection phase and the slotted patch EBG ground plane shows a compact size.

Low-Profile Wideband Metasurface Antennas Using Characteristic Mode Analysis

2017-02-17

Feng Han Lin , Zhi Ning Chen

A metasurface (MTS) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). An MTS radiator formed by a diamond-slotted patch is fed by a microstrip … A metasurface (MTS) antenna is proposed for low-profile and wideband operation based on characteristic mode analysis (CMA). An MTS radiator formed by a diamond-slotted patch is fed by a microstrip line at its bottom through a slot centered on a ground plane. The CMA is used for the modeling, analysis, and optimization of the proposed antenna in order to reveal the underlying modal behaviors of the MTS and to guide the mode excitation. It is found that an extraordinary quisiTM30 MTS mode and a slot mode both with wideband broadside radiation are formulated and well excited simultaneously, leading to a broadband operation. Empirical equations are outlined for speeding up design. To verify the concept, a 2 × 2 array with the overall size of 1.78λ 0 × 1.78λ 0 × 0.07λ 0 (λ 0 is the free-space wavelength at 5.5 GHz) is designed and prototyped at 5-GHz Wi-Fi bands. The achieved impedance bandwidth for 10-dB return loss is 31% with the gain of 13-14.5 dBi over the operating bandwidth.

Simple and Accurate Analytical Model of Planar Grids and High-Impedance Surfaces Comprising Metal Strips or Patches

2008-06-01

Olli Luukkonen , Constantin Simovski , Gérard Granet +4 more

This paper introduces simple analytical formulas for the grid impedance of electrically dense arrays of square patches and for the surface impedance of high-impedance surfaces based on the dense arrays … This paper introduces simple analytical formulas for the grid impedance of electrically dense arrays of square patches and for the surface impedance of high-impedance surfaces based on the dense arrays of metal strips or square patches over ground planes. Emphasis is on the oblique-incidence excitation. The approach is based on the known analytical models for strip grids combined with the approximate Babinet principle for planar grids located at a dielectric interface. Analytical expressions for the surface impedance and reflection coefficient resulting from our analysis are thoroughly verified by full-wave simulations and compared with available data in open literature for particular cases. The results can be used in the design of various antennas and microwave or millimeter wave devices which use artificial impedance surfaces and artificial magnetic conductors (reflect-array antennas, tunable phase shifters, etc.), as well as for the derivation of accurate higher-order impedance boundary conditions for artificial (high-) impedance surfaces. As an example, the propagation properties of surface waves along the high-impedance surfaces are studied.

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Reflectarray Antennas

2024-12-01

José A. Encinar , Daniel Martinez‐de‐Rioja , Eduardo Martinez‐de‐Rioja

Abstract This chapter gives an overview of reflectarray antennas, covering from their historical development to the latest applications. A reflectarray antenna consists of an array of phase‐shifter cells, which are … Abstract This chapter gives an overview of reflectarray antennas, covering from their historical development to the latest applications. A reflectarray antenna consists of an array of phase‐shifter cells, which are preadjusted to generate a collimated or shaped beam, when illuminated by an external source. The chapter describes different types of reflectarray cells, analysis and design techniques, as well as some realizations for bandwidth improvement, multifrequency operation, and beam scanning. Various selected applications of reflectarray antennas in radar, imaging, and communications are described. Some of them are already commercialized as automotive radars and imaging scanners for security. Finally, some challenging examples of satellite antennas are shown, such as spaceborne interferometer radars, contoured‐beam antennas for broadcasting, large inflatable reflectarrays, multibeam antennas for satellite communications, and high‐gain antenna for data transmission in CubeSats.

Light-activated bandgap modulation of active tunable metamaterials with folded structure

2025-06-24

Yang Meng , Dan Wang , Lifeng Wang +2 more | Smart Materials and Structures

Abstract This study presents the design of an active tunable metamaterial beam constructed from a folded structure fabricated by light-activated shape memory polymer (SMP). The stiffness of light-activated SMP is … Abstract This study presents the design of an active tunable metamaterial beam constructed from a folded structure fabricated by light-activated shape memory polymer (SMP). The stiffness of light-activated SMP is modulated by ultraviolet (UV) illumination, a phenomenon attributed to the photo-elastic coupling response. The design integrates the Euler-Bernoulli beam model with local resonance theory to achieve tunable mechanical properties. Through comprehensive theoretical analysis and numerical simulation, the bandgap ranges of the tunable metamaterial beam across various configurations are systematically calculated. Additionally, the intricate relationships between the bandgap, UV illumination time, and geometric parameters are explored and analyzed. The results reveal that both the upper and lower limits of the bandgap shift toward higher frequencies as the illumination time increases or the number of structural folds grows, thereby demonstrating active bandgap tuning capability of the metamaterial beam. Finally, experimental validation confirms the vibration suppression efficacy of the light-activated metamaterial beams. These beams exhibit pronounced vibration damping and isolation effects within frequency bands near their intrinsic resonance. Notably, the bandgap frequency range of the light-activated metamaterial beams can be substantially modified through UV irradiation for different time, or by augmenting the number of structural creases. Compared to traditional fixed-bandgap metamaterials, this design achieves a 10% upward bandgap shift under 90 s UV irradiation and a 150% bandwidth increase using double-layered folds, with a response speed of seconds—significantly outperforming the minute-scale response of thermal actuation. This rapid, remote, non-contact tuning capability facilitates applications in lightweight vibration reduction in aerospace, vibration isolation of precision instruments, and dynamic control of flexible robots.

A low cost all-dielectric water based resonant absorber

2025-06-24

Avinash Avinash , Nisha Gupta | Analog Integrated Circuits and Signal Processing

High-accuracy and Broadband Polarization Detection via Metasurface Vector Beam Modulation

2025-06-24

Hao Han , Fang Yao , Zhongheng Diao +6 more | Photonics Research

Metamaterial Frequency Selective Surface for 5G Applications

2025-06-23

Mohammad Tariqul Islam , Mohammad Lutful Hakim , Touhidul Alam | CRC Press eBooks

Multi-frequency narrow-band near-perfect transmission of frequency selective surfaces through artificial magnetic conductor metamaterials

2025-06-23

Guang Lu , Geng Liu , Ziheng Lin +2 more | Journal of Applied Physics

This study designed and implemented a method for multi-frequency narrow-band frequency selective surface (FSS) by using artificial magnetic conductor (AMC) metamaterials. By analyzing AMC unit cells’ reflection characteristics, this study … This study designed and implemented a method for multi-frequency narrow-band frequency selective surface (FSS) by using artificial magnetic conductor (AMC) metamaterials. By analyzing AMC unit cells’ reflection characteristics, this study developed and fabricated single-frequency, dual-frequency, and tri-frequency AMC units, which were then combined to form certain FSS structures. Theoretical and experimental results show that these FSS structures can enhance transmissions at specific resonance frequencies, thus enabling multi-frequency narrow-band filtering. This study expands FSS multi-frequency selection features, while providing a solution for boosting spectrum utilization of wireless communication systems.

A 3D Printed Multibeam Circularly Polarized Luneburg Lens Antenna Based on Anisotropic Metamaterials

2025-06-23

Yuhui Ren , Tianyi Wang , Kailong Ji +5 more | Optics Express

Polarization Insensitive Dual Band Planar Metamaterial Surface Design for Antenna Applications

2025-06-23

Mohammad Tariqul Islam , Mohammad Lutful Hakim , Touhidul Alam | CRC Press eBooks

Capacitive Frequency‐Selective Surfaces Metamaterial Design and Microwave Absorption Characterization for 2–8 GHz Applications

2025-06-21

Xiang Gao , Mengke Qiao , Pingan Chen +2 more | physica status solidi (b)

The article designs a novel low‐frequency metamaterial absorber based on frequency‐selective surfaces (FSS) to address the balance of performance and structural thickness of low‐frequency electromagnetic wave absorbers. In addition, its … The article designs a novel low‐frequency metamaterial absorber based on frequency‐selective surfaces (FSS) to address the balance of performance and structural thickness of low‐frequency electromagnetic wave absorbers. In addition, its performance mechanisms are thoroughly investigated. The proposed absorber comprises three primary layers: resistive ink, lossy dielectric, and metal backplane. The FSS design is guided by simulated equivalent circuit theory with structural parameters optimized using the Trust Region Framework. Simulation results demonstrate that the absorber achieves a reflection loss ( RL ) < −2 dB at 2 GHz and less than −4 dB across the entire C‐band, with a total thickness of only 2 mm. Further analysis of the physical mechanisms reveals that the absorber's excellent performance is primarily attributed to the capacitive components of the FSS. Experimental measurements align with simulation results, showing over 90% agreement. This study provides an effective design methodology for developing thin electromagnetic wave absorbers, offering promising prospects for applications in compact electronic systems.

Low‐Profile Fabric‐Based Ultra‐Wideband Metamaterial Absorber Design

2025-06-20

Baojun Chen , Hao Yuan , Teng Jiao +2 more | physica status solidi (RRL) - Rapid Research Letters

Wearing electromagnetic protective equipment enables the absorption or reflection of electromagnetic waves that are incident on the human body, thereby reducing the risk of health issues associated with electromagnetic pollution. … Wearing electromagnetic protective equipment enables the absorption or reflection of electromagnetic waves that are incident on the human body, thereby reducing the risk of health issues associated with electromagnetic pollution. Although fabric‐based metamaterial absorbers can overcome the drawbacks of traditional electromagnetic shielding gear, such as excessive weight and low efficiency, achieving broadband absorption under low‐profile conditions remains challenging due to the inherently low dielectric constants of fabric materials. This study proposes a lightweight metamaterial absorber utilizing wool felt as the dielectric substrate and a polyethylene (PE) conductive film as the resonant layer for the frequency‐selective surface (FSS). Leveraging the excellent conductivity and high sheet resistance of the PE film, the nested square‐ring structure of the FSS exhibits strong resonant behavior. As a result, the absorber demonstrates absorption rates exceeding 90% across the 3.91–27.52 GHz frequency range, achieving a relative absorption bandwidth of 150.24% with an overall thickness of only 0.109 . Experimental measurements in a microwave anechoic chamber validate the absorber's angular and polarization insensitivity, in conjunction with excellent flexibility that maintains high absorption efficiency even under mechanical deformation. Furthermore, numerical simulations confirm that the absorber retains stable performance under humid environmental conditions.

Inverse-designed metasurfaces for multifunctional spatial frequency filtering

2025-06-20

Phillippe Pearson , Gregory Roberts , Andrei Faraon | Optica

Broadband reflectarray antenna using a novel multifrequency phase synthesis method

2025-06-19

Pei Chen , Zeqi Pan , Zhang-Qi Liao +4 more | AEU - International Journal of Electronics and Communications

Reconfigurable Metasurface with In-Band Transmission-Reflection Dynamic Switching and Wideband RCS Reduction

2025-06-19

Yi Quan , Chao Song , Xin Ge Zhang +1 more | Journal of Optics

Abstract Development of radar technology has driven the demand for advanced electromagnetic (EM) structures that not only can reduce radar cross section (RCS) but also enable efficient signal transmission as … Abstract Development of radar technology has driven the demand for advanced electromagnetic (EM) structures that not only can reduce radar cross section (RCS) but also enable efficient signal transmission as required. However, achieving a synergy between wideband stealth and reconfigurable transmission on one platform remains a challenge, especially for the case where the incident angle and polarization of EM waves are insensitive. Here, we propose a dual-polarized transmissive-reflective reconfigurable metasurface (TRRM) that enables real-time switching between in-band transmission and reflection modes while achieving wideband RCS reduction across entire operating frequencies in both modes. In such a metasurface, we use the diodes for dynamic EM transmission-reflection switching and incorporate curved-line miniaturized elements to enhance angular stability. To achieve wideband RCS reduction, the binary particle swarm optimization algorithm is adopted for the TRRM design. As a verification, a TRRM consisting of 6 × 6 subarrays is fabricated and measured. The results demonstrate that the TRRM can achieve reconfigurable transmission and effective RCS reduction for large-angle EM wave incidences. Our design provides a promising solution for radar related applications in complex and ever-changing EM environments.&#xD;

Supercell-Based Metasurfaces for Arbitrary Polarization Beam Splitting: Physics-Informed U-Net Design with High Extinction Ratio

2025-06-18

Yongmei Pan , Hongshun Liu , Zhi Qun Cheng +3 more | Optics Express

Ultrahigh-Q quadrupole resonance quasi-BICs excited with different polarized light in an all-dielectric metasurface for refractive index sensing

2025-06-18

Zhichao Wang , Tuanxin Liang , Hui Zhang | Optics Communications

Reconfigurable Reflectarray Structure Based on Optimized Unit Cell for Wireless Communications

2025-06-18

Reham Mahood Yaseen , Ali Khalid Jassim | Journal of Telecommunications and Information Technology

This paper presents a 180 × 180 × 1 mm reconfigurable reflector array structure based on an optimized unit cell for wireless communication applications. The reflector array contains 144 unit … This paper presents a 180 × 180 × 1 mm reconfigurable reflector array structure based on an optimized unit cell for wireless communication applications. The reflector array contains 144 unit cells placed on the FR4 substrate, and each unit cell structure uses a single layer based on multi-concentric square rings. The single layer is used to obtain negative εr and μr values, while multiple rings provide a wide reflection bandwidth. The proposed structure is characterized by dual reflection bandwidth. The first band (2.6 GHz) ranges from 1.98 GHz to 4.6 GHz, while the other band (1.71 GHz), ranging from 7.41 GHz to 9.1 GHz. The reconfigurability of the structure is realized by using PIN diodes connected to each unit cell. Phase distribution in the proposed reflector structure changes according to state of the diodes, resulting in the reflection of the wave at different angles. The proposed solution was simulated in terms of S parameters, constitutive parameters and refractive index based on a full-wave analysis performed using CST Microwave Studio.

Integrated Control of Radiation and Reflection Waves Based on the Circular-Polarization Metasurface

2025-06-17

Qian Zhu , Han Wei Tian , Chao Song +4 more | Journal of Physics D Applied Physics

Abstract Integrated control of electromagnetic (EM) radiation and reflection waves is critically important to meet high demands of wireless service performances in increasingly complex EM environment. Current approaches for modulating … Abstract Integrated control of electromagnetic (EM) radiation and reflection waves is critically important to meet high demands of wireless service performances in increasingly complex EM environment. Current approaches for modulating both radiation and reflection waves typically require separate design of metasurface and antenna structure, while achieving direct, independent, and flexible control of both wave types through a simple structure remains a significant challenge. Herein, a circular-polarization radiation-reflection-integrated metasurface (RRIM) is proposed to address this issue. Such a RRIM modulates the geometry phase and the propagation phase in tandem to obtain uncorrelated radiation and reflection phase distributions, enabling independent and simultaneous realization of distinct functionalities with orthogonal circularly-polarized states. As a proof of concept, two prototypes are fabricated and measured. One RRIM prototype can achieve dual-beam radiation with arbitrary gain allocation as well as radar cross section (RCS) reduction. The measured gains of the two beams are 19.91 dBic and 25.06 dBic respectively, and the total aperture efficiency is 39.35%. The measured 10 dB RCS reduction bandwidth is 8-12 GHz for co-polarized waves and 10-10.8 GHz for cross-polarized waves. The other RRIM prototype can display two independent holographic images in radiation and reflection channels. The calculated Pearson correlation coefficients of two holograms reach 82.28% and 70.31%. Both the simulated and measured results validate the performances of RRIM. We believe the RRIM has great potentials in wireless communications and radar applications.

A multifunctional metasurface with linear-to-linear and dual-band linear-to-circular reflective polarization conversion

2025-06-16

C. Wang , Zhaoyang Shen , Qinghe Zhang +1 more | Journal of Physics D Applied Physics

Abstract This paper presents a novel reflective metasurface that can perform high-performance linear-to-linear and linear-to-circular polarization conversion for SatCom and radar sensing in the X, Ku, K, and Ka bands. … Abstract This paper presents a novel reflective metasurface that can perform high-performance linear-to-linear and linear-to-circular polarization conversion for SatCom and radar sensing in the X, Ku, K, and Ka bands. The proposed unit cell is based on a composite elliptical design created through Boolean operations of six differently sized ellipses on a dielectric slab with a metal plane. Numerical simulations demonstrate that the designed metasurface realizes linear-to-linear polarization (LP-LP) conversion with a polarization conversion ratio exceeding 90% in 9.45-12.72 GHz. Meanwhile, it enables linear-to-circular polarization (LP-CP) conversion in two distinct bands: 14.28-21.95 GHz and 25.37-27.73 GHz, with axial ratios below 3 dB. In these bands, it converts linearly polarized incident waves into left-handed circularly polarized (LHCP) and right-handed circularly polarized (RHCP) waves, respectively, exhibiting multifunctionality across different frequencies. The measured results of the fabricated prototype highly agree with numerical simulation results. This multifunctional metasurface has great application potential in many fields such as satellite links, radar systems, next-generation wireless communication, sensing, and stealth technology.

Numerical and experimental reassessment of Eurocode 3 design rules for cellular beam end-posts

2025-06-16

Georgios Psyrras , Konstantinos Daniel Tsavdaridis , R. Mark Lawson | Journal of Constructional Steel Research

Semiconductor MOF Metamaterials Enable Thin Structures with Robust Electromagnetic Wave Absorption

2025-06-16

Ning Qu , Yinglai Hou , Xicheng Zhang +5 more | Small

Developing thin electromagnetic wave (EMW) absorbers with ultra-broadband absorption is challenging, as current designs often struggle to achieve high causality efficiency (Rc), which measures effective absorption bandwidth (EAB) relative to … Developing thin electromagnetic wave (EMW) absorbers with ultra-broadband absorption is challenging, as current designs often struggle to achieve high causality efficiency (Rc), which measures effective absorption bandwidth (EAB) relative to thickness (ideal Rc is 1). Herein, a broadband semiconductor metal-organic framework (SC-MOF) metamaterial is proposed that approaches the Rc limit. The design synergizes both the micro and macro properties of the materials. On the micro scale, a 2D SC-MOF (CuHT) with a few-layer structure and tailored conductivityis synthesized, promoting a balance of attenuation and impedance matching to create an efficient EMW lossy network. On the macro scale, CuHT is dispersed in epoxy resin to form trapezoidal structures, with scattering topological design further enhancing causality efficiency and robustness. The CuHT metamaterial achieves an exceptional EAB of 33.4 GHz at just 3.9 mm thickness (Rc = 1.14), with stable performance under oblique incidence (within ±45°) and various polarizations. This advancement holds tremendous promise for developing robust EMW absorbers with superior performance.

Variable-order Perfect Vortex Beam Generation Method and Tolerance Analysis Based on Metasurface

2025-06-16

Sheng Luan , Peng Zhang , Yuanxin Wang +3 more | Optics Express

Liquid metal-based electromagnetic metasurface for continuous RCS reduction adjustment

2025-06-16

Ping Li , Nuo Xu , Yang Zhou +7 more | Optics Express

A novel elastic dome array structure for precise pressure regulation toward tunable microwave absorption

2025-06-14

Chuyang Liu , Lin Zhu , Shiqi Zheng +4 more | Acta Materialia

A Broadband Millimeter-Wave Circularly Polarized Folded Reflectarray Antenna Based on Transmissive Linear-to-Circular Polarization Converter

2025-06-14

Yue Cao , Zhuwei Wang , Qing Wang +2 more | Micromachines

In this paper, a wideband circularly polarized folded reflectarray antenna (CPFRA) based on a transmissive linear-to-circular polarization converter is proposed. The CPFRA consists of a primary reflector and a sub-reflector. … In this paper, a wideband circularly polarized folded reflectarray antenna (CPFRA) based on a transmissive linear-to-circular polarization converter is proposed. The CPFRA consists of a primary reflector and a sub-reflector. To achieve broadband performance, a metasurface-based RA element on the primary reflector surface and a transmissive linear-to-circular polarization converter on the sub-reflector surface are applied. Moreover, the transmissive linear-to-circular polarization converter on the sub-reflector surface helps convert linear polarization to circular polarization. To verify the proposed CPFRA, a prototype is designed, fabricated, and tested. The measured results exhibit that the proposed CPFRA presents a 3 dB gain bandwidth of 27.4% and a 3 dB axial ratio bandwidth of 23%. The CPFRA achieves a peak gain of 21.2 dBi with an aperture efficiency of 27.2%. The proposed CPFRA is a promising candidate for millimeter-wave (mm-W) satellite communication applications because of its advantages of high gain, low cost, low profile, and broad bandwidth.

Multi-layer Frequency Selective Surface Wideband Filter with High Selectivity Operating in L, S, and C Bands

2025-06-13

Vincenzo Violi , Danilo Brizi , Agostino Monorchio | Research Square (Research Square)

<title>Abstract</title> This paper presents the design and analysis of a novel 2D multilayer frequency selective surface (FSS) passband filter conceived for broadband response with pronounced roll-off characteristics. Unlike conventional 2D … <title>Abstract</title> This paper presents the design and analysis of a novel 2D multilayer frequency selective surface (FSS) passband filter conceived for broadband response with pronounced roll-off characteristics. Unlike conventional 2D structures, the proposed multi-layer architecture improves bandwidth and filter selectivity while preserving an easy manufacturing process. The design is carried out by adopting a layer-by-layer equivalent circuit extraction technique that allows accurate impedance tailoring in order to accomplish the desired behavior in the L, S and C bands. The complete structure is composed by 3 stacked FSS layers, opportunely separated by foam gaps, achieving a compact 67 mm overall thickness. The performance predicted by the analytical modelling was also confirmed through full-wave simulations and experimental measurements, highlighting an excellent agreement. The proposed filter achieves an extensive-3 dB pass-band from 2.79 GHz to 6.65 GHz, reaching 90% of fractional bandwidth, with sharp roll-offs of 42 dB/GHz and 70 dB/GHz. Thus, the-10 dB rejection bands cover the 1.2 GHz – 2.62 GHz and the 6.75 GHz – 7.9 GHz ranges, accomplishing a full operation coverage of L, S and C bands. Finally, the filter's lightweight and affordable design makes it particularly suitable for modern communication systems that require effective out-of-band attenuation with elevated selectivity and compact integration.

Passive Frequency Tunability in Moiré-Inspired Frequency Selective Surfaces Based on Full-Wave Simulation

2025-06-12

Jieun Hwang , Sungcheol Hong | Micromachines

This paper presents a simulation-based investigation of passive frequency tunability in frequency-selective surfaces (FSSs) enabled by Moiré pattern interference. By overlapping two identical hexagonal FSS layers and introducing rotational misalignment … This paper presents a simulation-based investigation of passive frequency tunability in frequency-selective surfaces (FSSs) enabled by Moiré pattern interference. By overlapping two identical hexagonal FSS layers and introducing rotational misalignment between them, we demonstrate that the resulting Moiré patterns induce significant shifts in the resonance frequency without any external bias or active components. Using full-wave simulations in HFSS, we show that rotating the second layer from 0° to 30° can shift the resonant frequency from 4.4 GHz down to 1.2 GHz. This tunable behavior emerges solely from geometrical manipulation, offering a low-complexity alternative to active tuning methods that rely on varactors or micro-electromechanical systems (MEMSs). We discuss the theoretical basis for this tuning mechanism based on effective periodicity modulation via rotational interference and highlight potential applications in passive reconfigurable filters and refractive index sensors. The proposed approach provides a promising route for implementing tunable electromagnetic structures without compromising simplicity, power efficiency, or integration compatibility.

High-performance embeddable spatial differential metasurfaces by the spatial-frequency-based inverse design method

2025-06-12

Weiji Yang , Junjie Li , Zin Lin +2 more | Photonics Research

Miniaturized broadband absorber based on fractal structure metasurface

2025-06-12

Pufan Bai , Hui Deng , Zixiong Liu +3 more | Journal of Applied Physics

A broadband metasurface microwave absorber with a miniaturized size is presented under two mechanisms. A frequency selective surface based on the Minkowski (MSK) fractal structure is constructed to provide a … A broadband metasurface microwave absorber with a miniaturized size is presented under two mechanisms. A frequency selective surface based on the Minkowski (MSK) fractal structure is constructed to provide a lower resonance frequency with the similar size, and the Salisbury screen is designed to create high-frequency resonance. Then, a second-order MSK fractal ring is loaded to realize impedance matching over the entire bandwidth. The absorption performance of the metasurface absorber (MA) proposed is validated by the equivalent transmission line model, the Smith chart, and the surface current distribution. The simulation results demonstrate an absorption bandwidth of 125% with an absorption rate of &gt;90% over 0.3–1.3 GHz. The thickness of the proposed absorber is 0.075λ, and the size of the unit cell is 0.1λ. The developed absorber exhibits stable absorption performance for both TE and TM polarizations within an incident angle of 40°. The experimental results agree with those of full-wave simulation.

Electromagnetic diffraction and resonance characteristics of 3D PEC double disks excited by a Hertzian dipole oriented and located arbitrarily using method of auxiliary sources

2025-06-11

Emre İşcan , Vasıl Tabatadze , Ertuğrul Karaçuha | Journal of Electromagnetic Waves and Applications

Angle-invariant scattering in metasurfaces

2025-06-10

NULL AUTHOR_ID | Physical review. B./Physical review. B