Performance Enhancement of a Planar Slot Phased Array by Using Dual-Mode SIW Cavity and Coding Metasurface

This communication presents a planar phased array designed with an enhanced reflection bandwidth, a wide-angle scan, and a broadband low backscattering. On one hand, an improved substrate integrated waveguide (SIW) cavity-backed slot antenna which supports dual resonant modes is designed and utilized as the array element. The dual-resonance element presents the advantages of wideband reflection, wide-beam radiation, and compact size, which has the benefit for the wideband wide-angle scan of the proposed phased array. On the other hand, a coding metasurface, which consists of four specially arranged unit cells, is presented and surrounds the slot array. Based on the specially designed coding metasurface, the array gain is enhanced and a broadband scattering reduction is realized. Both simulated and experimental results indicate that the designed phased array supports a main-beam scan up to 60° and a 3 dB beam coverage up to 75° in an active reflection band of 10.1-11.6 GHz. Besides, the results also show that the radar cross section (RCS) has the reduction from 6.2 to 16.3 GHz and from 6.2 to 15.2 GHz for TM and TE polarizations, respectively.