Low-RCS and Wideband Reflectarray Antenna With High Radiation Efficiency

This communication presents a wideband high-efficiency reflectarray antenna with a low radar cross section (RCS) based on metal pillars inserted absorptive frequency-selective reflector (AFSR). The AFSR is realized by the bent resistor-embedded metal strip, whose multimode resonance is utilized to obtain the wideband absorption-reflection-absorption performance. In addition, the realized AFSR is with compact lattice spacing characteristics, which enhances the antenna's radiation efficiency. Then, the metal pillars with variable heights are inserted into the AFSR serving as a phase shifter to flexibly control the reflection phase within the wide reflection band. Simulated and measured results show that the proposed reflectarray antenna has a pencil-beam radiation pattern from 6 to 8 GHz with an aperture efficiency up to 60.4%. Additionally, two RCS reduction bands with the fractional bandwidth of 66.7% and 32.3% are obtained.