Sidelobe Suppression for Wideband Slotted SIW Cavity-Backed Antenna Array

Abstract

A slot antenna array backed by substrate integrated waveguide (SIW) cavity with high gain, wideband and low sidelobe levels (SLLs) is proposed in this letter. Four 2 × 2 slots antenna elements based on SIW cavity are used as the radiation structure. A broadband SIW corporate-feed network is equipped on the bottom layer to feed antenna array. Due to the broadband characteristics of antenna element and feed network, antenna array with wide band is obtained. Then, through the dislocation distribution of antenna elements, the SLLs of antenna array can get greatly reduced. A prototype has been fabricated using standard PCB process, and measured for verification. As for the measurement results, the impedance bandwidth below -10 dB is from 18.2 GHz to 21.7 GHz (17.5%). The maximum gain is 17.4 dBi at 20.5 GHz. Most importantly, the SLLs of both E- and H-plane are all lower than -15 dB in the working band.