Evanescent Mode Cylindrical Cavity Filter

Application ID: 12015

An evanescent-mode cavity filter is resonant at a frequency lower than its original fundamental mode frequency. Evanescent mode resonance can be realized by creating a discontinuity or reactance inside the cavity.

The basic model was modified by the addition of a metal box at either end representing a housing. Inside a dielectric substrate and a microstrip line coupled into the cavity.

The electric field distribution shows that the dielectric tube inside the cavity does not distort the distribution significantly.

This model example illustrates applications of this type that would nominally be built using the following products: