3-D Absorptive Frequency Selective Reflector for Antenna Radar Cross Section Reduction

TLDR

The paper proposes a design methodology for a frequency selective reflector with dual‑sided absorption bands. The method employs multimode resonators within a 3‑D unit cell to achieve an absorption‑reflection‑absorption response, analyzed with an equivalent circuit model and demonstrated by integrating the reflector with monopole and dipole antennas. Simulations, fabrication, and measurements show that AFSR‑backed antennas achieve a –10 dB radar‑cross‑section reduction with fractional bandwidths of 64.7 % at 3.4 GHz and 41 % at 8.3 GHz, while maintaining radiation characteristics and improving realized gains by 0.9 dB for monopoles and 2.3 dB for dipoles.

Abstract

A methodology for designing a frequency selective reflector with two-sided absorption bands is proposed. This method is based on utilizing multimode resonators inside a 3-D unit cell to obtain an absorption-reflection-absorption response. Detailed analysis of this 3-D absorptive frequency selective reflector (AFSR) is provided with the aid of an equivalent circuit model to reveal the operating principle. To show the benefit of the new structure in antenna's radar cross section reduction (RCSR), a dual-polarized 3-D-AFSR integrated with monopole and dipole antennas are simulated, fabricated, and then measured. Compared with their counterparts with normal ground plane, AFSR-backed antennas have shown a remarkable out-of-band RCSR. The -10 dB RCSR has fractional bandwidths of at least 64.7% and 41% with center frequencies of 3.4 and 8.3 GHz, respectively. The radiation characteristics of AFSR-backed antennas are nearly maintained. The realized gains are enhanced by 0.9 and 2.3 dB for monopole and dipole antennas mounted on a 3-D-AFSR, respectively.