WIDEBAND BALANCED FILTERS ON SLOTLINE RESONATOR WITH INTRINSIC COMMON‐MODE REJECTION

This chapter proposes several novel wideband balanced bandpass filters (BPFs) with intrinsic common‐mode (CM) rejection. The hybrid microstrip‐slotline structure is used in the chapter in order to maintain the intrinsic CM rejection. A more generalized hybrid slotline multimode resonator (MMR) is also proposed by two kinds of transmission line, that is, microstrip line and slotline, and it is utilized to design an alternative wideband balanced BPF with intrinsic CM rejection. The chapter shows the three‐dimensional view and top view of the two proposed balanced BPFs on slotline MMR, respectively. In each filter, a slotline resonator is formed on the middle ground plane of a two‐layer substrate, and its multimode resonance is utilized to build up a wideband balanced BPF. Furthermore, the chapter explains working mechanisms and design methods of the wideband balanced filters, theoretically demonstrated and experimentally validated over a wide frequency range for both differential‐mode (DM) and CM frequency responses.