Low-Profile Dual-Band Filtering Antenna Using Common Planar Cavity

A dual-band filtering antenna with orthogonal polarizations in the two bands is presented. The antenna is based on the single-layer substrate integrated waveguide (SIW) technology. A dual-mode rectangular SIW cavity with two orthogonal modes functions as a common high-Q resonator, leading to the compact size of the proposed design. The dual-mode cavity is coupled to two orthogonally polarized slot-loaded SIW cavities for radiation. The low-profile antenna shows broadside peak gain of 5.94 dBi at low-band operating frequency of 4.3 GHz with a 3 dB bandwidth of 2.4%, while it shows 6.45 dBi gain at 5.02 GHz with 3 dB bandwidth of 6% for the high band.