A planar balanced‐to‐balanced filtering power divider with in‐band common‐mode suppressions and self‐isolation

Abstract

A compact balanced-to-balanced (BTB) filtering power divider (FPD) with in-band common-mode (CM) suppressions based in a single-layer substrate-integrated waveguide (SIW) is presented in this article. This FPD mainly consists of one full-mode and two half-mode SIW cavities where each cavity's differential-mode (DM) and CM are designed reasonably. The filtering DM signals to dual-ports power division is realized with a simple and compact configuration. Moreover, the CM signals can be naturally rejected without any additional isolation circuits. Ultimately, the BTB FPD with a center frequency of 10.5 GHz is designed, fabricated, and measured to verify the proposed design concept, which shows below −15 dB 6% DM filtering fractional bandwidth (FBW). The CM transmission is suppressed below −22 dB over 28.6% FBW. The proposed design exhibits the advantages of compact size, simple design, low loss, planarity, and multi-function fusion.