Compact Substrate Integrated Waveguide Slot Antenna Array With Low Back Lobe

In this letter, a compact substrate integrated waveguide (SIW) slot antenna array with a comb-shaped choke is proposed for low back-lobe radiation. The comb-shaped choke consists of an array of quarter-wavelength short-end parallel microstrip lines on the bottom surface of the array for lowering the backward radiation by suppressing the diffraction at the edges of the substrate. The proposed antenna array operating at 10 GHz exhibits a 10-dB back-lobe reduction compared to the antenna without the choke.