Hybrid Inline TE/TM Mode Dielectric Resonator Filters with Wide Spurious Free Range and Controllable Transmission Zeros

In this paper a third order dielectric hybrid bandpass filter based on TE and TM mode ceramics is presented. The dominant TE 01δ and TM 010 modes are utilized to design the passband. A TM mode dielectric resonator (DR) is used to suppress the spurious modes of the TE mode DRs while the TE mode DRs are used together with the input/output couplings to create two independently controllable transmission zeros by exciting higher order modes (HOM). To validate the approach, the designed filter is manufactured and its measurement results are compared with the simulation results. A suitable filter topology and coupling matrix are derived and discussed.