High-Gain Horn Antenna With Bandpass Filter-like Response Based on Filtering RGW-to-SIW Transition

In this paper, a rectangular waveguide to substrate integrated waveguide (RWG-to-SIW) transition structure with extra bandpass filter-like response is proposed and employed for filtering horn antenna design. The transition structure consists of a SIW cavity loaded with a slotted patch and a filtering T-shaped SIW. The SIW cavity is used as waveform transformer to excite the stepped waveguide horn. The slot in the patch can introduce a transmission zero at the right of the passband. The terminal of the filtering T-shaped SIW operating in half-TE 110 mode is designed to generate the desired transmission zero at the left of the passband. The simulated results show that the proposed lowprofile filtering horn antenna can realize a high peak gain of 11.7 dBi, a wide $\mathbf{- 1 0 - \mathrm { dB }}$ impedance bandwidths of $\mathbf{9. 4 5 \%}$ from 27.4 to 30.1 GHz, and good bandpass filtering response.