A Dual-Band Mixed-Coupled Substrate Integrated Waveguide Filtering Antenna

A dual-band mixed-coupled substrate integrated waveguide (SIW) filtering antenna is presented in this paper. The dual-mode rectangular SIW cavity with two orthogonal modes acts as a common resonator, which is coupled to two radiating elements through coupling windows. The radiating elements consist of a rectangular SIW cavity with an annular slot and a circular patch resonator with metallized vias. The circular patch is embedded in a rectangular SIW cavity. The feed probe is located in the aforementioned common rectangular SIW cavity. Mixed-coupling occurs between rectangular slot SIW cavity and the circular patch resonator, which introduces radiation zeros in the high stopband of dual passbands. Meanwhile, the frequency selectivity of the lower stopband is further enhanced by introducing nine metal vias. The gain of the antenna is 6.76 dBi at 9.6 GHz and the -3 dB bandwidth for low band is 5.7%. The gain is 7.40 dBi at 12 GHz and the -3dB bandwidth for high band is 5.9%.