Mixed combline and He11 mode dielectric resonator filter with improved spurious performance

A novel mixed resonator filter structure is presented which consists of a combination of combline resonators and the HE₁₁ mode DR loaded rectangular cavity for obtaining an improved spurious response performance. The resonator structures are analysed using a parallel FD-TD method coupled with digital filtering and the matrix pencil method. The computed resonant frequencies for both the resonators compare well with measured results. The accuracy of the matrix pencil method is compared with the MUSIC algorithm for the prediction of resonant frequencies from FDTD data. A slot-coupled 3-pole filter composed of mixed combline and HE₁₁ mode resonators is designed and constructed and the measured results indicate the usefulness of the new configuration