Compact Microstrip Patch Filtenna Array Based on Reusable High-Order SIW Cavity

Abstract

In this letter, a compact microstrip patch (MP) filtenna array designed by reusing high-order substrate integrated waveguide (SIW) cavity is investigated. The SIW cavity operating at TE <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">201</sub> mode not only acts as the first-stage resonator of the filter, but also serves for the four-way dividing realized by the mode power allocation. In addition, by appropriately controlling the coupling coefficient of the output window of the SIW cavity, the radiating 2 × 2 MP array can become the second-stage resonator of the filter. Finally, benefiting from the reuse of the employed high-order SIW cavity, the proposed filtenna array exhibits good performance such as low loss, high efficiency and compact structure. For demonstration, a filtenna array prototype centered at 13.6 GHz is fabricated and tested, showing 13 dBi peak gain and 90% peak efficiency. Good agreement is obtained between simulated and measured results.