Phase controllable FSR design and its application into a high-gain transmitarray antenna with a low radar cross-section

Abstract

In this study, a high-gain transmitarray antenna (TAA) is proposed to achieve a low radar cross-section (RCS) with polarization-insensitive characteristic. Initially, an anisotropic frequency selective rasorber (FSR) structure is constructed by a detailed analysis of the current distributions and parameter adjustments. Hence, manipulations of absorption and transmission are achieved, along with covering a transmission phase cycle by rotating the element at 90°. Then, employing a phase-controllable FSR and focal length optimization, a low-RCS and high-gain TAA is presented. For the radiation case, the proposed antenna has a pencil pattern with a peak gain of 21.8 dBi. The F/D ratio is low when a wide-beam feed is utilized. At scattering state, in-band and out-of-band 6 dB RCS reductions are realized ranging from 7.6 to 10.4 GHz and 11.6–12.4 GHz compared to the reference TA. Moreover, its bistatic RCS is reduced in approximately ±90° of angular space under normal incidence. The effectiveness of the proposed design is verified by experiments.