Filtering Antenna With Quasi-Elliptic Response Based on SIW H-Plane Horn

Abstract

A filtering antenna with a quasi-elliptic response based on the substrate-integrated waveguide(SIW) H-plane horn is presented. It is mainly composed of two symmetrical horn elements embedded with the trapezoidal dual-mode cavity. By exploiting the cross couplings of the dual-mode cavity, two radiation nulls are introduced on the gain curve showing a quasi-elliptic filtering response without the increase of horn size. Then, a modified transition is printed in front of the horn aperture on both sides of the substrate, which acquires wider impedance bandwidth and maintains a low backlobe radiation throughout the bandwidth. Besides, the proposed antenna is designed, fabricated, and measured at Ku-band. Two measured radiation nulls can be observed at 14.02 and 17.98 GHz, where the gain drops significantly to below −28 and −38 dBi, leading to high frequency selectivity. A wide measured impedance bandwidth of 12.2% and a large front-to-back ratio of more than 20 dB are achieved. To the author s best knowledge, it is the first time that the filtering horn antenna with radiation nulls, wide bandwidth, and excellent radiation is designed.