A novel Miniaturized SIW Diplexer Based on Orthogonal Dual-Mode Resonator

A novel miniaturized substrate integrated waveguide (SIW) diplexer with intrinsic inter-channel isolation based on orthogonal TE201 and TE102 modes in the substrate-integrated dual-mode resonator is proposed in this paper. Through proper design of input/output coupling configuration, high intrinsic isolation performance of the uplink and downlink channels can be obtained. As a result of the common orthogonal substrate-integrated dual-mode resonator (DMR) serving as T-junction, the diplexer realized miniaturization. A second-order direct-coupled SIW diplexer operated at 12 and 14 GHz is designed and manufactured to validate the concepts, and the isolation better than 39 dB has been achieved within the operation frequencies.