Ultra-wideband and polarization-insensitive RCS reduction of microstrip antenna using polarization conversion metasurface

A new type of polarization conversion metasurface (PCM) is presented to reduce radar cross section (RCS) of microstrip antenna. The proposed PCM consists of evolved split ring (ESR) resonators. Through designing of the PCM unit cell with five resonances and symmetrical layout, a high polarization conversion ratio and ultra-wideband passive cancellation are achieved. The proposed antenna (with PCM) and a reference antenna are designed, simulated and measured. The measured results show that our proposed antenna can achieve 10 dB in-band and 5 dB out-of-band RCS reduction in an ultra-wide frequency band from 6 GHz to 26.7 GHz. Moreover, the PCM works efficiently for both x- and y-polarized incident waves. The measured results show a good agreement with the simulations. Compared to previous researches, the proposed PCM features a compact profile and wider operating bandwidth of RCS reduction.