Dual-band dielectric resonator bandstop filters

This article presents the design and implementation of a new asymmetric dual-band bandstop filter using TE01δ mode dielectric resonator (DR) technology. The coupling matrix is generated by frequency transformation technique applied to advance filtering functions for direct-coupled asymmetric dual-band bandstop filter in cul-de-sac configuration. The proposed approach provides control of all the major parameters such as center frequencies, intercavity couplings, and input/output couplings of filter independently in both the designated bands. The dual-band DR filters (2 × 2) pole, with return loss = 15 dB and percentage rejection bandwidth of 1.6 and 0.6% in two bands, at 9.96 and 10.15 GHz, respectively, are designed, built, and tested. The measured and simulated results are in good agreement over the desired band.