A study on a BPF with dual-pass bands using EH11δ mode and HE11δ mode dielectric rod resonators

We need two band-pass filters (BPF) to realize a filtering system having two discrete passbands. In this report, we propose a BPF with dual-pass bands using EH<11δ> mode and HE<11δ> mode dielectric rod resonators. The BPF has probes that excite only EH<11δ> mode or HE<11δ> mode. Therefore, two discrete passbands can be obtained with one dielectric ring resonator. Furthermore, EH<11δ> and HE<11δ> modes are orthogonal dual modes and can be employed as a coupled resonator respectively. So the BPF is smaller than that of single mode resonators. The BPF having the two passbands with the center frequencies of 2.7 GHz and 3.0GHz is test-manufactured.