Cross-coupled narrow bandpass filters with asymmetric transmission zeros ca
n be realized in cascaded tri-section topology.(1,2,3) Each tri-section cre
ates a single transmission zero below or above the passband. The realizatio
n of resonator tri-sections is relatively difficult due to the interaction
between the couplings. This article shows ow three-dimensional electromagne
tic (3D-EM) analysis, together with extraction of an equivalent circuit mod
el, can speed up the realization process of cascaded tri-section bandpass f
ilters.