Ultra-wideband RCS reduction and gain enhancement of patterned-surface-based aperture coupling patch antenna with optimized arrangement method

A patterned-surface-based aperture coupling patch antenna (ACPA) with ultra-wideband radar cross section reduction (RCSR) and gain enhancement is presented in this paper. Due to the air-filled gap structure of the ACPA, an air spacer is introduced to design double-layer patterned surface (PS), which broadens the RCSR bandwidth of ACPA. Moreover, to obtain better gain of antenna, the arrangement of PS is optimized based on its current distributions. Experimental results show that impedance matching of PS-based ACPA is preserved well and operation band is broadened slightly from 8.0 to 11.3 GHz. The boresight gain is enhanced from 7.5 to 11.5 GHz, with a peak gain enhancement of 4.1 dB at 9.7 GHz. Meanwhile, the PS-based ACPA possesses the ability of specular RCSR over the band 3.0-20.0 GHz for both polarizations. The 10-dB RCS reduction of the antenna is achieved almost from 5.5 to 17.0 GHz for normal incidence.