Novel Bandpass Filters by Using Cavity-Loaded Dielectric Resonators in a Substrate Integrated Waveguide

This paper presents novel bandpass filters by using a triple-mode dielectric resonator (DR) implemented in a substrate integrated waveguide (SIW). The resonant frequency and unloaded Q-factor of the DR were first calculated and simulated by Ansoft HFSS. The dimensions of the DR were then determined. A single triple-mode SIW loaded with a DR filter with tuning elements was designed, simulated, and measured. Spurious suppression with source and load couplings, as well as fabrication tolerance, was analyzed. A six-mode filter that uses two DRs was also proposed and measured. These filters exhibit close agreements between the simulation and measurement results and have the advantages of low insertion loss, compact configuration, and easy integration with other planar circuits. The proposed concept is very attractive for designing low cost, low insertion loss, and miniaturized filters for wireless communication systems.