Wideband RCS Research Articles

Simplistic metasurface design approach for incident angle and polarization insensitive rcs reduction

This paper proposes the design of a metasurface for polarization and incident angle-insensitive RCS reduction applications. An ellipse-shaped unit cell is utilized as a polarization converter, which is then arranged to form a checkerboard surface. While a single layer checkerboard structure gives a wideband RCS reduction, a double layer structure yields polarization and incident angle independent operation. The two layers have unit cells rotated 450 to each other. Experimental results demonstrate an RCS reduction bandwidth of around 90%. Further the RCS reduction remains stable with polarization and incident angle variation.

An AMC-based low-RCS conformal phased array design

Abstract In this article, an integrated radiation and scattering performance array conformed with the cylinder is presented. Wideband RCS reduction can be achieved and the radiating performance is maintained without loading any other structures. Two different antenna units with similar radiation performances and different reflection phases are designed to form a 6 × 6 conformal array. To verify the simulation results, a prototype of a 6 × 6 units integrated conformal array was fabricated and measured. The experimental results show that the proposed conformal array has better scanning performance above ±40° in the range of 8.2–11.3 GHz. In addition, the monostatic RCS reduction of the proposed array is more than 5 dB covering the working band of the array antenna with a maximum reduction value of 24.2 dB. The measured results agree well with the simulation results.

Cusp Phased Metasurfaces for Wideband RCS Reduction Under Broad Angles of Incidence

Cusp Phased Metasurfaces for Wideband RCS Reduction Under Broad Angles of Incidence

Wideband RCS Reduction Metasurface Based on Printing Resistive Graphene Ink

Wideband RCS Reduction Metasurface Based on Printing Resistive Graphene Ink

Optimization of wideband RCS reduction via controlled phase and amplitude in metasurface design

Optimization of wideband RCS reduction via controlled phase and amplitude in metasurface design

Wideband RCS Reduction of Fabry-Perot Resonator Antenna Based on Diffuse Scattering Method

Wideband RCS Reduction of Fabry-Perot Resonator Antenna Based on Diffuse Scattering Method

Wideband RCS Reduction for Circular-polarized Slot Array Antennas Based on Composite Metasurface

Wideband RCS Reduction for Circular-polarized Slot Array Antennas Based on Composite Metasurface

Transparent and Flexible Chessboard Metasurface Based on Optimized Multielement Phase Cancellation for Wideband RCS Reduction

Transparent and Flexible Chessboard Metasurface Based on Optimized Multielement Phase Cancellation for Wideband RCS Reduction

Identification of Control Parameters Using Taguchi Method for Hybrid Real-Binary Differential Evolution Algorithm and Its Applications in Electromagnetic Optimization

The hybrid real-binary differential evolution (HDE) algorithm has been proficient in addressing electromagnetic optimization problems (EOPs) involving both real and binary variables. However, its optimization performance on different control parameter (CP) settings is not further studied, and the method to determine the values of CPs is more likely to use the trial-and-error method, which lacks universality on both unimodal and multimodal benchmarks. To completely account for the effect of CPs in HDE, the Taguchi method is utilized to identify the values of each CP. The orthogonal experiment result is the average rank of the mean values of 23 benchmark functions obtained by HDE and other classic optimization algorithms. Based on the analysis of variance results, three CPs that have a major effect on the performance of HDE are selected, and each of them is changed from level 1 to level 5 to further obtain the best combination of CPs, which is indicated as HDEN1. To further enhance the local search ability of HDEN1 for the global best, a modified algorithm (HDEN2) is proposed based on a novel mutation strategy selection method, and the simulation results demonstrate that the minimum values obtained by HDEN2 are smaller than those obtained by HDEN1. Two EOPs, including planar microwave absorber and Yagi-Uda antenna designs, are solved to validate the performance of HDEN1 and HDEN2. The results reveal that the HDEN1 and HDEN2 outperform HDE, demonstrating the efficacy of the proposed method for identifying the CPs of HDE. In the end, a low profile and wideband RCS reduction pixelated checkboard metasurface is optimized utilizing the HDEN2, proving that the proposed algorithm can be a good candidate for hybrid real-binary electromagnetic problems.

Wideband RCS reduction of microstrip antenna using artificial magnetic conductor metasurface

Wideband RCS reduction of microstrip antenna using artificial magnetic conductor metasurface

Wideband RCS Reduction of a Linear Patch Antenna Array Using AMC Metasurface for Stealth Applications

Wideband RCS Reduction of a Linear Patch Antenna Array Using AMC Metasurface for Stealth Applications

High-temperature metasurface for polarization conversion and RCS reduction

In this study, we present a high temperature-resistant linear-to-linear polarization conversion metasurface for wideband RCS reduction in the microwave regime. The linear-to-linear polarization conversion metasurface is composed of a single layer high-temperature-resistant metallic pattern array. When linearly polarized waves impinge on the metasurface, the polarization conversion rate is greater than 90% from 9 GHz to 16.8 GHz at 800°C. The polarization conversion unit arrangement forms a checkerboard configuration metasurface, which can effectively reduce RCS reflection. The wideband RCS reduction mechanism is scattering cancellation rather than absorption. The metasurfaces were designed, fabricated, and measured, which can realize linear-to-linear polarization conversion and wideband RCS reduction. The simulation results and measurement results are all in good agreement. Meanwhile, the measurement provides a solid verification for our design. The results provide an alternative method to reduce the RCS at high temperatures.

Wideband RCS Reduction by Single-Layer Phase Gradient Modulated Surface.

This paper deals with the design and fabrication of an unpretentious (single-layer, without any lump element) broadband (97%, 11.3–32.3 GHz) radar cross-section reduction (RCSR) modulated surface (MS). The proposed structure uses sinusoidal modulation gap sizes between square patches within square unit cells to form a phase gradient that plays an effective role in improving the RCSR bandwidth. An MS with dimensions of 250 × 250 mm2, consisting of 40 × 40 unit cells with a period of 6 mm printed on a RO4003C (lossy) substrate of 0.06λLF (λLF being the wavelength at the lower frequency) thickness, has been prototyped. The MS has square patch (SP) unit cells with seven different gap sizes. A genetic algorithm (GA)-based fine-tuning has been implemented to further increase the performances of the structure. Measurements on it have been conducted considering both mono- and bi-static arrangements and for oblique incidences for both TM and TE polarization tests. A good agreement between simulation and measurement results proves the validity of the design criteria.

Wideband Radar Cross Section Reduction of Microstrip Patch Antenna using Polarization Converter Metasurface

Antenna is the key device of communication on stealth platform. It is the greatest contributor to the overall RCS. So, it is desired to reduce the radar signature of the antenna. In this paper, a novel antenna is designed using polarization converter metasurface. The polarization converter metasurface converts the polarization of the incident wave into its orthogonal component. This PCM structure is loaded around patch antenna to reduce the RCS of the antenna over wide frequency range. With this novel design, the overall RCS reduction bandwidth of 140.57% is obtained for the frequency range of 3.49 GHz – 20 GHz. In addition to this, the 10 dB RCS reduction bandwidth is obtained for the frequency ranges of 8.84 GHz – 10.42 GHz (16.41%) and 16.99 GHz – 17.81 GHz (4.71%). The design shows excellent angular stability for both TE and TM polarization. Discernible Bistatic Radar Cross Section reduction is obtained over a wide frequency range. Simulation and experimental results show that there is no degradation in antenna radiation pattern and other parameters. So, with this novel design the problem of obtaining wideband RCS reduction of a microstrip patch antenna is addressed without degradation in radiation pattern along with excellent angular stability for both the polarization modes.

Wideband RCS reduction due to plasma generated by radioactive nuclei for cylindrical object

Radar cross section reduction has been one of the most important research topics in recent years. Plasma-based stealth is a method of reducing the radar cross section, which dampens the electromagnetic waves and reduces the amount of return waves. In this paper, a coating of the radioactive nucleus ^{241}{mathrm{Am}} on the surface of the cylinder with a radius of 10 cm is considered and the range of the emitted alpha particles and the electron density generated in the air are obtained using the Geant4 code under standard temperature and pressure conditions. By finite element method solution, the radar cross section of the conductive cylindrical object has been simulated and extracted in the presence and absence of plasma created by alpha-particles. The obtained results show a reduction of 5–8 dB mathrm{m}^2 in the radar cross section in the frequency range of 2–12 GHz for specific activity source of 1 Ci/mathrm{cm}^2.

BPSO and Staggered Triangle Layout Optimization for Wideband RCS Reduction of Pixelate Checkerboard Metasurface

A wideband radar cross section (RCS) reduction method is proposed based on checkerboard metasurface, which is one of the promising solutions for higher efficiency and better performance. First, the metasurface is pixelated into a checkerboard, and the algorithm of binary particle swarm optimization is introduced for the artificial magnetic conductor (AMC) pattern design on the checkerboard metasurface. In the proposed method, only one AMC pattern is designed to achieve the phase difference with dielectric substrate that is the necessary condition in RCS reduction, which significantly simplifies the AMC design and greatly improves its designing efficiency. Second, the number of elements in metasurface, which constitutes the unit cells, is optimized by full-wave simulation. Furthermore, we exploit unit cells under a staggered triangle layout for better grating lobe and vertical RCS reduction, and it improves the angle and polarization stability effectively compared with the traditional square layout. Finally, the simulation and experiment results demonstrate the effectiveness of the proposed wideband RCS reduction design.

A Novel Method for Rapidly Solving Wideband RCS by Combining UCBFM and Compressive Sensing

A Novel Method for Rapidly Solving Wideband RCS by Combining UCBFM and Compressive Sensing

Broadband RCS reduction for both microstrip array and Fabry‐Perot antenna based on the quasi‐ AMC superstrate

This article presents a new type of quasi-AMC superstrate (QAMCS), which can achieve wideband RCS reduction (RCSR) for both the microstrip array and Fabry-Perot (FP) antenna. The proposed QAMCS comprises of two-layer metallic patterns with a thin air gap. The top-layer consists of two types of frequency selective surfaces (FSSs) in a checkerboard layout, and the wideband RCSR is realized based on the phase cancelation principle. The bottom-layer consists of the slotted FSS, to reflect out-of-band signal while allowing the in-band signal to pass through with a low insertion loss. Besides, the reflection phase of the proposed QAMCS is about −180° around higher frequencies. Therefore, it can be regarded as a partially reflecting surface (PRS) to construct the FP antenna with a highgain and low-RCS. The simulation and measurement results show that the bandwidth of 10-dB RCSR is more than 76% (7.2-16.1 GHz). The 10-dB impedance bandwidth of the array antenna is ranging from 16.6 to 18.6 GHz. For the FP antenna, its aperture efficiency is 31.5% and the peak gain is 17.5 dBi at 20 GHz.

A metasurface-enabled Fabry–Pérot (FP) circularly polarized antenna with continuous wideband polarization conversion purity

Abstract In this paper, a wideband continuous pure right hand circularly polarized (RHCP), high gain, and low-radar cross-section (RCS) array antenna is proposed. A linear-to-circularly polarization conversion (LCPC) Metasurface (MS) is employed as the superstrate of the Fabry–Pérot (FP) resonator antenna, consisting of two oblique slits etched patches located at top and bottom, respectively, and a metal ring with corner-cutting patch inside, that ensure a wideband transmission and reflection LCPC frequencies ranging from 9 to 22 GHz, and 7–13.5 GHz, respectively. While, a pure RHCP LCPC frequency band of 9–12 GHz is produced by adopt the proposed MS that is benefit from the design of etched oblique slits and corner-cutting patch surrounded by the metal ring, where the magnitude and phase difference can be kept in the variation of ±3 dB and 10°, respectively. Then, a rectangle patch-fed MS FP antenna is designed by an arrangement of 5 × 5 MS unit cells. Following this, the sequence rotated technique is utilized to arrange the array antenna by 2 × 2 units, ensuring a wide band RCS frequency band. The proposed array antenna is fabricated and measured, which indicated the correctness of this design for performance of high gain, low RCS, and wideband pure RHCP. Compared with recent reported MS-based FP works, a wideband LCPC frequencies purity is obtained, and a good radiation and scattering performance is obtained in the design.

A Four-leaf Clover-shaped Coding Metasurface For Ultra-wideband Diffusion-like Scattering

In this paper, a novel four-leaf clover-shaped coding metasurface is proposed and applied to achieve an ultra-wideband diffusion-like scattering. The proposed metasurface element has rotational symmetry; hence, it produces similar reflection characteristics for both x- and y-polarized waves. To realize a 1-bit coding metasurface, two elements are chosen that have a phase difference of 180°±37° from 15.5 to 40.5 GHz. An optimization algorithm is applied to get the best arrangement of unit cells in the array to attain the wideband RCS reduction. The four-leaf clover-shaped metasurface can attain more than 10 dB RCS reduction from 15.5 to 26.5 GHz and 30.5 to 40.5 GHz. A prototype of the proposed design is fabricated, and an experiment is carried out to validate the performance of the metasurface. The proposed concept of four-leaf clover-shaped coding metasurface is an effective solution for wideband RCS reduction applications.