The present invention uses TE01(n) single-mode resonators in different orientations that are cascaded along an evanescent mode waveguide. By exploiting multiple orthogonal evanescent modes that can alternatively by-pass, or excite the resonators, cross-coupling between non-adjacent resonators is established and properly controlled. Pseudoelliptic filters are realized without using cumbersome cross-coupled architectures, or reduced spurious performance multi-mode resonators. A 6th order filter with two transmission zeros in the lower stopband, a 5th order filter with three transmission zeros, and an 8th order filter with four transmission zeros are included as embodiments of the present invention.
展开▼
