A partially dielectric-filled waveguide bifurcation structure is proposed t
o realize wideband bandpass filters. By using modal expansion and matching
the tangential fields at the discontinuity, a variational expression for th
e input admittance is obtained. The Ritz method is used to form a group of
linear equations from which the actual admittance can be obtained; then the
equivalent-circuit parameters of the discontinuity are achieved. It is con
firmed that the structure is capable of realizing wideband filters. A numer
ical analysis of a filter example is conducted to justify the validity. (C)
2001 John Wiley & Sons, Inc.