Showing papers by "Kumar Vaibhav Srivastava published in 2022"
DOI•
TL;DR: In this article , a single-layer compact copolarized shorted TM 1/2,0 mode microstrip patch antenna is presented for in-band full-duplex application.
Abstract: In this letter, a single-layer compact copolarized shorted TM1/2,0 mode microstrip patch antenna is presented for in-band full-duplex application. Two shorted TM1/2,0 mode patch antennas, used for transmission and reception purposes, make the structure compact. The wideband behavior of the patch antenna is obtained by fusing the two resonances, one because of the shorted TM1/2,0 mode radiating patch and the other because of the λ/4 line resonator. To enhance the isolation between the transmitter and receiver antenna, a novel defected ground structure is used. Slots are introduced into the ground plane to create a weak field region for the basic antenna element. The other antenna element (receiver) is located in the weak field region to enhance isolation. Further enhancement in isolation is achieved by introducing a T-shaped metallic strip into the slots. The structure is proposed with the credits of compactness, enhanced bandwidth, colinear polarization, very less fabrication complexity, low profile, and high isolation. The proposed structure is fabricated and measured. The structure experimentally exhibits a bandwidth (≤ −10 dB) of 2.42–2.52 GHz with the isolation of 25 dB, peak isolation of 36 dB, and an average realized gain of 4 dBi in the entire band.
5 citations
TL;DR: In this article , an optically transparent, lightweight, and conformable metastructure that exhibits multispectral signature management capabilities despite its extremely low-profile configuration was designed and demonstrated.
Abstract: This work pertains to the design, numerical investigation, and experimental demonstration of an optically transparent, lightweight, and conformable metastructure that exhibits multispectral signature management capabilities despite its extremely low-profile configuration. In comparison to the existing hierarchical approaches of designing multispectral stealth solutions, attention has been paid to accommodate the conflicting requirements of radar and infrared (IR) stealth using a single metasurface layer configuration, which required a few constraints to be incorporated during the design stage to ensure compatibility. This methodology promulgates the desired multispectral response with minimal manufacturing footprint and facilitates an efficient integration with the other existing countermeasure platforms. The resulting design exhibits a polarization-insensitive and incident angle stable broadband microwave absorption with at least 90% absorption ranging from 8.2 to 18.4 GHz. Concomitantly it also exhibits an averaged IR emissivity of 0.46 in the 8–14 µm long-wave IR regime, along with high optical transparency (71% transmission at 632.8 nm). Notably, the total thickness of the metastructure stands at 0.10 λL ( λL corresponds to the wavelength at lowest frequency). The metastructure has been fabricated with indium tin oxide coated polyethylene terephthalate sheets, on which the frequency selective pattern is machined using Excimer laser micromachining, and the performances are verified experimentally. Furthermore, a hybrid theoretical model has been developed that not only provides crucial insights into the operation of metastructure but also presents a methodical semi-analytical approach to design.
5 citations
TL;DR: In this paper , a wideband bidirectional endfire circularly polarized (CP) antenna is proposed by combining two endfire CP antennas with a single coaxial probe feed, and the wideband characteristics are achieved with the help of a two-layered substrate separated by an air gap.
Abstract: In this paper, a wideband bidirectional endfire circularly polarized (CP) antenna is proposed by combining two endfire CP antennas with a single coaxial probe feed. The wideband characteristics are achieved with the help of a two-layered substrate separated by an air gap, and the excitation of CP waves in the endfire directions is yielded by the wideband magnetic dipoles and tapered electric dipoles. The proposed CP antenna has shown wide 10-dB impedance bandwidth (IBW) and 3-dB axial ratio bandwidth (ARBW) of 20.76% (5.05 - 6.22 GHz) and 16.10% (5.14 - 6.04 GHz), respectively. Besides showing an overall size of 0.733λL × 0.863λL× 0.058λL (λL is the wavelength corresponding to the lowest operating frequency) with wide operational bandwidth, the proposed CP antenna has also demonstrated a desirable peak gain of 4.45 dBic.
3 citations
3 citations
TL;DR: In this article , a polarization-insensitive frequency-selective rasorber (FSR) with wideband absorption and in-band transmission characteristics is presented and investigated.
Abstract: A polarization‐insensitive frequency‐selective rasorber (FSR) with wideband absorption and in‐band transmission characteristics has been presented and investigated in this letter. The unit cell of the proposed FSR comprises one lossy and one lossless resonator, both printed on FR4 substrates and segregated by an air spacer. Resistive ink patterns are deposited in the top lossy layer to realize a wideband absorption, displaying significant improvement over the existing FSR structures. The absorption bandwidths are obtained from 1.31 to 3.22 GHz and 4.88 to 6.69 GHz having fractional bandwidths of 84.32% and 31.28%, respectively. An in‐band transmission response is occurred, due to the bottom lossless layer, at 4.05 GHz between the two absorption bands with a small insertion loss. The equivalent circuit model is used to develop the proposed FSR and the design variables are formulated accordingly to generate the desired passband and stopband characteristics. Variation in the incident and reflected/transmitted wave properties have also been studied and the topology is found to be polarization‐insensitive as well as angularly stable. Finally, the structure has been fabricated and measured to validate the FSR design principle and its performance.
3 citations
DOI•
TL;DR: In this article , simulations were performed to study the effect of dielectric constant and thickness of adhesive on the microwave characteristics of polyethylene terephthalate (PET) and polydimethylsiloxane (PDMS)-based microwave metamaterial absorber (MMA).
Abstract: Bonding of the heterogeneous layers of polymers as a trilayered (or multilayered) transparent metamaterial absorber (MA) is challenging, since the hydrophobic nature of interfacial surfaces does not allow direct bonding. Apart from the mechanical challenges to bond, microwave and optical functionalities of the chosen material need to be studied quantitatively for an optimal choice. Therefore, simulations are performed to study the effect of dielectric constant and thickness of adhesive on the microwave characteristics of polyethylene terephthalate (PET)–polydimethylsiloxane (PDMS)-based microwave MA (MMA). Composites of polyvinyl butyral (PVB) and 3-aminopropyltriethoxy silane (APTES) that address the need for strongly adhesive yet transparent in optical regime and non-interacting in the microwave regime have been developed. Lap-shear tests with plasma-treated PET–PDMS adherends demonstrated to have lap-shear adhesion strengths greater than 0.21 MPa. The optical transmittance of electromagnetic (EM) waves through MA after being adhered with glue is 74.9%. A numerical analysis shows that the proposed microwave absorber absorbs more than 90% of EM waves within the range of 7.97–20.72 GHz after an additional layer of optimal adhesive, which is validated through experiments conducted in anechoic measurements.
2 citations
TL;DR: In this paper , a wideband low-profile endfire circularly polarized (CP) antenna using magnetoelectric dipole is proposed, where the magnetic dipole was enhanced by reducing the resonance frequency of higher-order mode half-TE310 with the help of rectangular slots placed at the null of mode half−TE310.
Abstract: In this article, a wideband low‐profile endfire circularly polarized (CP) antenna using magnetoelectric dipole is proposed. Designing a wideband electric dipole element is easy and well‐studied in the literature. However, designing a compact wideband magnetic dipole element is still a challenge. In this paper, the impedance bandwidth (IBW) of the magnetic dipole is enhanced by reducing the resonance frequency of higher‐order mode half‐TE310 with the help of rectangular slots placed at the null of mode half‐TE310. By combining the resonance frequency of mode half‐TE110 and mode half‐TE310, the magnetic dipole can yield a larger IBW (6.86–7.67 GHz, 11.14%) with smaller planar dimensions of 1.259λ0 × 0.363λ0 × 0.038λ0 (λ0 is the free space wavelength at the centre frequency). To generate a wideband endfire CP wave, a horizontally polarized electric dipole with a feed line is combined with the vertically polarized magnetic dipole. The measured IBW and axial ratio bandwidth (ARBW) are 11.65% and 12.02%, respectively, with a measured peak endfire gain of 5 dBic. The overall dimension of the proposed wideband low‐profile endfire CP antenna is 1.11λ0 × 0.66λ0 × 0.033λ0.
2 citations
10 Jul 2022
TL;DR: In this paper , the authors used the shooting and bouncing ray approach to characterize the bistatic RCS of an electrically large, open ended cylindrical cavity using a transparent and flexible metamaterial absorber.
Abstract: Open ended cylindrical cavities occur in many places of large complex structures. Hence Radar Cross Section (RCS) characterization of this structure is quite important. In this article characterization of bistatic RCS of an electrically large, open ended cylindrical cavity using the shooting and bouncing ray approach is carried out. Next, the structure is wrapped (both inside and outside) with a transparent and flexible metamaterial absorber made of Indium Tin Oxide (ITO) coated Polyethylene Terephthalate (PET) substrate and reduction in bistatic RCS is observed.
2 citations
12 Dec 2022
TL;DR: In this paper , a two-layer profile system is used to increase the impedance bandwidth (IBW) of the circularly polarized (CP) antenna, which has a measured maximum gain of 5.47 dB and an endfire polarization purity of 18 dB at the centre frequency.
Abstract: A wideband endfire circularly polarized (CP) antenna using magnetoelectric dipole (magnetic and electric dipoles) is proposed and investigated. The vertically polarized magnetic dipole is formed using a three-sided closed cavity and opened at one side. A feed line connects a vertically polarized magnetic dipole and a horizontally polarized electric dipole to create a CP wave in the endfire direction. A two-layer profile system is used to increase the impedance bandwidth (IBW) of the CP antenna. To validate the simulation results, measurements of the antenna parameters of the proposed structure are performed. The proposed endfire CP antenna provides (5.56-6.3 GHz) 12.47% IBW and (5.59-6.11 GHz) 8.88% axial ratio bandwidth (ARBW). The proposed endfire CP antenna has a measured maximum gain of 5.47 dBic and an endfire polarization purity of 18 dB at the centre frequency. The complete dimension of this antenna is 0.907λL x 0.498λL × 0.064λL, where λL is the lowest frequency of the IBW.
12 Dec 2022
TL;DR: In this paper , two designs have been proposed for cylindrical dielectric resonator based unit cell for realization of microwave absorber, which provides broad absorption bandwidth with wide angle of incidence.
Abstract: Dielectric resonator based microwave absorber is investigated here which provides broad absorption bandwidth with wide angle of incidence. Two designs have been proposed for cylindrical dielectric resonator based unit cell for realization of microwave absorber. In first design, the ring dielectric resonator is investigated, whereas for second design the concentric cylinder along with ring dielectric resonator is used in unit cell geometry. The proposed absorbers work in C, X and Ku bands which establishes the structure to have broadband absorptivity signature over a wide range of incident angles. The advantages of these absorbers are ultra-broadband absorption without using multiple layers of resistive sheets or any other bulky elements. Moreover, the absorbers are completely 3D printable and economically efficient if we want to extend the technology to large scale manufacturing.
12 Dec 2022
TL;DR: In this paper , a single-layer radar absorber (RA) design, simulation, and fabrication method based on the screen printing approach is presented, which has an absorption of more than 90% from 1.05 GHz to 2.14 GHz covering L band.
Abstract: In this paper, a single-layer radar absorber (RA) design, simulation, and fabrication method based on the screen printing approach i.e resistive ink printed on FR-4 are presented. The proposed prototype has an absorption of more than 90% from 1.05 GHz to 2.14 GHz covering L band. The design is polarization insensitive and stable for oblique electromagnetic wave incidence up to 30 degree for both TE and TM polarization. The result of equivalent circuit model serves as confirmation for full wave simulation result. The fabricated prototype shows measured reflection coefficient below −10 dB from 1.05 GHz to 3 GHz (fractional bandwidth of 96%) with the thickness and periodicity of only 0.070λ$L$ and 0.076λ$L$ respectively. To understand the differences between the simulation and measurement results, further simulations with the variation of ink thickness and airgap have been performed. Based on these simulations, the RA with modified parameters (ink thickness of 0.02 mm and air gap of 22.5 mm) has a reflection coefficient below −10dB from 1.1 GHz to 2.74 GHz. The profile of the RA is only 0.086λ$L$ with periodicity of 0.076λ$L$. Wide range of applications may be possible due to the structure's lightness and ease of fabrication.
12 Dec 2022
TL;DR: In this paper , an optically transparent polarisation insensitive wideband absorber for C, X, and Ku bands is presented, using an indium tin oxide (resistive film) coated on a polyethylene terephthalate (PET) sheet.
Abstract: This paper demonstrates a simple design of an optically transparent polarisation insensitive wideband absorber for C, X, and Ku bands. An indium tin oxide (resistive film) coated on a polyethylene terephthalate (PET) sheet is utilized to design the proposed absorber. It provides a 15 dB absorption bandwidth from 4.8 to 20 GHz spanning over the C, X, and Ku bands. The proposed design remains unchanged up to 45° for TE polarisation and up to 30° for TM polarisation under oblique incidence. An equivalent circuit layout is modeled to better comprehend the working principle of the presented structure. Anechoic chamber measurements are performed after the prototype is fabricated. The simulated response matched well with the measured result.
12 Dec 2022
TL;DR: In this paper , a polarization-insensitive frequency selective rasorber (FSR) with wide absorption band before the transmission band is presented, which achieves a reflection coefficient less than -10 dB in the range from 3.22 GHz to 13.80 GHz.
Abstract: This paper presents a polarization-insensitive frequency selective rasorber (FSR) with wide absorption band before the transmission band. The FSR consists of two layers, the top layer is lossy layer which contains lumped resistors, while the bottom layer is a frequency selective surface (FSS) based filter layer. The proposed structure achieves a reflection coefficient less than -10 dB in the range from 3.22 GHz to 13.80 GHz (124.2%). The absorption band (80%) extends from 2.86 GHz - 10 GHz (fractional absorption bandwidth of 111%) which covers C-band fully and S- and X-band partially. Additionally, the transmission band with minimum insertion loss of 0.33 dB occurs at 12.89 GHz. The structure has a thickness of 0.09λ with respect to the lowest frequency. The surface current distribution as well as some parametric variations are studied to develop an understanding of the working principle of the proposed rasorber. Equivalent Circuit Model (ECM) is used to guide the formation of structure. The prototype has been fabricated and measured and the measured results are in accordance with the simulated results.
12 Dec 2022
TL;DR: In this article , the authors investigated the electromagnetic response of ITO-PET sheets within X-band, before and after a thin layer of protective coating (dielectric constant between 2 and 3).
Abstract: The Indium Tin Oxide (ITO) coated Polyethylene Terephthalate (PET) sheets are potentially used to fabricate the transparent microwave metamaterial absorbers (MMA). However, the fragile ITO coatings easily get scratched during vigorous handling which deteriorate their electrical conductivity. Consequently, electromagnetic performance of such MMA structures changes over time. This can be controlled by packaging the MMA using polymer protective coating. Simulations are performed to investigate the EM response of ITO-PET sheets within X-band, before and after a thin layer of protective coating (dielectric constant between 2 and 3). Microwave absorption of ITO with sheet resistance equal to 10 $\Omega/\square$ (ITO (10)) and 100 $\Omega/\square$ (ITO (100)) found to be 9.6% and 45.3% before as well as after the coating of thickness ranging between 10 to 30 µm, After these protective coating, the MMA employed with ITO (10) and ITO (100) also yield approximately similar microwave absorption within broad frequency range of 4–18 GHz and the angular response is also maintained. Hence, service life of MMA can be increased by using polymer protective coatings without any deterioration in their electromagnetic response.
27 Sep 2022
TL;DR: Using the artificial anisotropy (AA) parameters, an optimized six-step locally one-dimensional (LOD6) finite-difference time-domain (FDTD) method is developed in this article .
Abstract: Using the artificial anisotropy (AA) parameters, an optimized six-step locally one-dimensional (LOD6) finite-difference time-domain (FDTD) method is developed. The proposed AA-LOD6 method and the existing LOD6 method take same simulation time, but it exhibits significantly low numerical dispersion error than the existing LOD6 method. Further, the performance of the AA-LOD6 method is compared here with the existing LOD6 method for the different mesh-sizes, time-steps, and operating frequencies.
27 Sep 2022
TL;DR: In this paper , a two-port dual-band MIMO antenna with connectors is proposed for millimeter-wave (mm-wave) applications at 28 and 38 GHz frequency bands.
Abstract: This paper presents a two element dual-band multiple input multiple output (MIMO) antenna for millimeter-wave (mm-wave) applications at 28 and 38 GHz frequency bands. The proposed design consists of a printed monopole antenna with a split ring resonator (SRR) geometry in the top layer and an annular slot in the defected ground plane. A single antenna element along with the connector model has initially been designed with a detailed analysis and subsequently, the two-port MIMO antenna with connectors has been realized. By precisely optimizing the design parameters, the geometry exhibits broadside radiation performance at 28 GHz and 38 GHz. A considerable gain and wide impedance characteristics are also observed in both bands for both the antennas. Several MIMO parameters, such as envelope correlation coefficient, total active radiation coefficient, and channel capacity loss are also calculated, and the results are suitable for 5G mobile applications. Finally, both the antenna prototypes are fabricated and their results are in close agreement with the simulated responses, validating the proposed concepts
27 Sep 2022
TL;DR: In this article , a polarization-insensitive frequency selective rasorber structure with a highly selective transmission band is presented, which consists of a top lossy layer and a bottom lossless layer resulting in broadband absorption and narrow-band transmission responses, respectively.
Abstract: A polarization-insensitive frequency selective rasorber structure with a highly selective transmission band is presented in this paper. The unit cell of the proposed design comprises a top lossy layer and a bottom lossless layer resulting in broadband absorption and narrow-band transmission responses, respectively. The novelty of the topology lie in its selective in-band transmission response at 9.3 GHz (with a 3-dB bandwidth of 13%) appearing between two wide absorption bands, spreading between 3.6 to 8.10 GHz and 10.50 to 13.30 GHz (having above 80% absorptivity). The structure has several other advantages, such as low footprint, angular stability, and wide adaptability. An equivalent circuit model and several parametric variations are also carried out to explain the operating principle of the geometry. Finally, a sample prototype has been fabricated and experimentally demonstrated for validation.
12 Dec 2022
TL;DR: In this paper , a polarization-insensitive frequency selective rasorber (FSR) geometry with dual-transmission and dual-absorption band was proposed, which consists of one absorptive layer and one transmissive layer separated by an air spacer, and each one is realized by patterning geometries in a periodic arrangement.
Abstract: A polarization-insensitive frequency selective rasorber (FSR) geometry with dual-transmission and dual-absorption band has been presented in this paper. Two passbands appear inside a wide absorption band, thereby resulting in multiple absorption regions surrounding the transmission peaks. The proposed FSR comprises of one absorptive layer and one transmissive layer, separated by an air spacer, and each of them is realized by patterning geometries in a periodic arrangement. The transmission bands are obtained at 5.30 GHz and 8.10 GHz with insertion losses of 0.79 dB and 0.46 dB, respectively. A wide absorption band, originally realized between 2.26 GHz and 8.79 GHz, gets divided into multiple absorption regions due to the presence of in-band transmission peaks and shows two discrete absorption bands from 2.01 GHz to 4.95 GHz and 5.81 GHz to 7.45 GHz. The structure achieves an overall fractional bandwidth of 118.20% with respect to its centre frequency. Polarization-insensitivity as well as angular stability for different polarizations (till 30 angle of incidence) are also observed in the structure. As compared to the existing dual-transmission band rasorber geometries, the proposed FSR offers a simpler design topology, lower footprint, and larger operating bandwidth. Proposed structure has been fabricated and measured to verify proposed design.
12 Dec 2022
TL;DR: In this paper , a linearly polarized two-dimensional beam-forming antenna using electrically reconfigurable frequency selective surface (FSS) has been proposed, which can generate thirteen individual radiating modes, which interms radiating in thirteen individual direction in 3D space.
Abstract: A linearly polarized two-dimensional beam-forming antenna using electrically reconfigurable frequency selective surface (FSS) has been proposed in this manuscript. The antenna structure incorporates a coaxial fed patch antenna and a recon-figurable FSS layer, kept above the patch radiator at a height of 0.41λ0 (λ0 represents the free space wavelength at the resonant frequency). The reconfigurable superstrate FSS layer consists of 6× 6 unit cells. The dimension of each unit cell is 0.24λ0 ×0.24λ0. To make the FSS layer electrically reconfigurable, each unit cell consists of two PIN diodes. The FSS superstate is further divided in four sections and each section contains 3 × 3 unit cells. Each sections are connected to the individual biasing pads for the purpose of biasing. The overall dimension of the proposed structure is 1.6λ0 ×1.6λ0 × 0.44λ0. When the reconfigurable FSS is illuminated by the coaxial fed patch, the composite system can generate thirteen individual radiating modes, which interms radiating in thirteen individual direction in 3D space. The antenna operates at a resonant frequency of 4 GHz and a maximum gain of 8.06 dBi is achieved with a maximum of 34° tilting of the beam.
12 Dec 2022
TL;DR: In this article , the authors present a technique of optimizing the electrical and optical performance of transparent metamaterial absorbers manufactured with commercially available Polyethylene Terephthalate (PET) coated Indium Tin Oxide (ITO) sheets.
Abstract: Radar cross section (RCS) reduction is thoroughly studied among electrical engineers so as to attain stealth capabilities of any object of interest. One particular kind of absorber which is in high demand is of the transparent and flexible kind. Transparent absorbers find their applications in various defence related applications such as in wind shield of aircraft and vehicles. Manufacturing of transparent metamaterial absorbers is a challenge as it is always a trade off between electrical performance and maintaining optical transparency. In this paper the authors present a technique of optimizing the electrical and optical performance of transparent absorber manufactured with commercially available Polyethylene Terephthalate (PET) coated Indium Tin Oxide (ITO) sheets.
12 Dec 2022
TL;DR: In this article , two miniaturized artificial magnetic conductor (AMC) unit cells have been designed to reduce the RCS of microstrip patch antenna at X-band, and the results of the measurement show that they are in good agreement with simulated response.
Abstract: In this article two miniaturized artificial magnetic conductor(AMC) unit cells have been designed to reduce the RCS of microstrip patch antenna at X-band. The scattering performance of the patch antenna has been determined by using one checkerboard metasurface and one aperiodic metasurface to improve the scattering performance of the antenna. The antenna provides the wide impedance bandwidth of 26%. Because of the AMC metasurface's effectiveness in reducing surface waves, the antenna's radiating performance has been significantly enhanced as a result. While the results of the simulation show a remarkable RCS reduction of 14 dB throughout the X-band for both the polarizations, the results of the measurement show that they are in good agreement with simulated response. In order to facilitate a deeper comprehension of the scattering performance, 3D RCS plots have also been presented. The radiation performance of the antenna has been measured, and the results show a pattern that is almost identical to the one that was simulated.
12 Dec 2022
TL;DR: In this paper , a five-port multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is investigated for WLAN applications, where the antennas are arranged in such a manner that polarization and space diversity are established in between the antenna elements to improve the isolation between the ports.
Abstract: In this article, a five-port multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is investigated for WLAN applications. Four cylindrical dielectric resonator antennas (CDRAs) are positioned at the four different arms of a plus shaped substrate. The coaxial feed excites $HE_{11\delta}$ mode in each CDRA. The antennas are arranged in such a manner that polarization and space diversity are established in between the antenna elements to improve the isolation between the ports. Pattern diversity is created in the proposed geometry by exciting another mode $(\mathbf{TM}_{\mathbf{01}{\delta}})$ in the ring DRA. The ring DRA is placed at the center of the substrate. With this multiple diversity technique, more than 24 dB of isolation is achieved among the ports. The proposed antenna structure offers 10.16% of bandwidth covering band from 5.51 to 6.10 GHz. Based on the presented results, the proposed MIMO antenna may be suitable for WLAN 5.8GHz applications.
01 Dec 2022
TL;DR: In this paper , a frequency selective rasorber (FSR) with two absorption bands and an in-band transmission window is proposed, which has a two-layer geometry in which the top lossy layer consists of a circular ring having T shaped arm extensions with loaded lumped elements and a circular convoluted loop.
Abstract: In this paper, a frequency selective rasorber (FSR) with two absorption bands and an in-band transmission window is being proposed. The proposed structure has a two-layer geometry in which the top lossy layer consists of a circular ring having T shaped arm extensions with loaded lumped elements and a circular convoluted loop, whereas the lossless layer consists of an asterisk-based slot. The lossy and lossless layers are separated by an air spacer. The designed unit cell has a periodicity of $0.17\lambda_{\mathrm{L}}\times 0.17\lambda_{\mathrm{L}}$, where $\lambda_{\mathrm{L}}$ corresponds to the wavelength of the lowest absorption frequency. The equivalent circuit modelling (ECM) concept has been used to design the FSR unit cell. The parametric analysis has been done using the Full wave simulation software. The optimized FSR design exhibits an absorptivity of more than 80% in the frequency ranges of 2.68 GHz to 6.84 GHz and 8.59 GHz to 12.89 GHz. The 3dB transmission bandwidth is in the frequency range of 7.75 GHz to 8.99 GHz with a low insertion loss of 0.29dB at 8.35GHz. The proposed structure can be used for applications that require communication as well as stealth.