Design of a multilayer dual‐band balanced‐to‐balanced SIW filtering power divider

Abstract

A new compact multilayer dual-band balanced-to-balanced filtering power divider (FPD) based on substrate integrated waveguide (SIW) resonator is proposed in this Letter. Originating from the field distributions of resonant modes in the square SIW cavity, TE201-mode and TE203-mode are utilised to achieve desired differential-mode (DM) transmission and high common-mode (CM) suppression. Meanwhile, dual DM passbands are generated by reasonably coupling two SIW resonators in the back-to-back form with the help of four coupling apertures etched on the middle-layer ground. Besides, a pair of isolated resistors is loaded at back-diagonal regions of the upper-layer SIW resonator, achieving high port-to-port isolation. For demonstration, a prototype dual-band balanced-to-balanced SIW FPD operating at 11.0 and 18.4 GHz is ultimately designed, fabricated and tested. Good agreement between simulated and measured results is obtained, verifying the feasibility and validity of the design concept.