Suppressed back-lobe substrate-integrated waveguide slot array antenna for X-band

Utilising an array that is constructed by combining short-ended stubs and microstrip lines, a planar-choke structure is presented. By locating the proposed chock structure on the bottom of the substrate-integrated waveguide slot array antenna, undesired spillover current and edge diffractions are removed. Measurement result show that in the operational bandwidth the backward radiation is reduced by more than 20 dB and the side-lobe level is improved by 5 dB without degrading of the antenna´s electrical performance.