In-Band RCS Reduction of Circularly Polarized Microstrip Antenna Array Based on a Novel Feed Network

Abstract

In this study, a new method to reduce the in-band radar cross section (RCS) of a circularly polarized microstrip antenna array (CPMAA) based on a novel feed network is presented, which can independently regulate the radiation and scattering performances without loading metasurface or modifying the shape of the antenna element. Using the principle of the Van Atta antenna, the 180° phase difference between waves reradiated by the adjacent subarrays of the proposed CPMAA is realized by controlling the transmission phase of connected microstrip lines in the feed network; thus, the monostatic RCS is reduced by phase cancellation. Compared with the reference antenna array, the monostatic RCS of the proposed CPMAA is reduced in the frequency band of 3–5.4 GHz under both <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${x}$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${y}$ </tex-math></inline-formula> -polarized incident waves. The maximum monostatic RCS reduction value under <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${x}$ </tex-math></inline-formula> - and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${y}$ </tex-math></inline-formula> -polarized incident waves is 19.22 and 22.18 dB, respectively. To verify the validation of the proposed method, a prototype is manufactured and its performance measured. The measured results are in good agreement with the simulation ones.