Dual-Band Filtering Balun Based on Dual-Mode Dielectric Resonator

In this paper, a dual-mode dielectric resonator (DR) is investigated and utilized to design filtering balun with dual-band response. The properties of the dual-mode DR are analyzed in detail. According to the field distributions, the two modes can be simultaneously extracted as out-of-phase signals for differential applications. A dual-band filtering balun is designed, fabricated and measured, showing good performance of amplitude balance and 180° phase difference. Good agreement can be obtained between their respective simulated and measured results.