SIW-Slot-Fed Thin Beam-Squint-Free Fabry-Pérot Cavity Antenna With Low Backlobe Levels

The substrate integrated waveguide (SIW)-slot feeding structure is introduced in a fully substrate-integrated thin Fabry-Pérot cavity (FPC) antenna to achieve the boresight radiation free of beam squint and with low backward radiation levels. Single longitudinal slot symmetrically cut onto the broadwall (the ground plane of the FPC) of the SIW is proposed to feed the FPC antenna in order to point maximum radiation at boresight and avoid frequency-dependent beam squint caused by conventional asymmetrically edge-fed feeding patch. The beam-squint variation of 11.3 ° along with the edge-fed patch feed is significantly reduced to 0.3 ° within the operating bandwidth of 9.8-10.1 GHz using the proposed SIW-slot feed. The comparison of the radiation performance shows the proposed SIW-slot-fed FPC antenna suitable for integrated circuits.