A high stop-band suppression W-band waveguide E-plane filter for millimeter-wave applications

E-plane filter have been widely used in microwave and millimeter-wave circuits for its high Q value, low loss and easy to realized. In this paper, a low-order W-band Wave guide E-plane fin-line band pass filter are used to provide high harmonics suppression for millimeter-wave devices such as six frequency multiplier. The equivalent circuits of the filter are analyzed and a simple CAD method is introduced for E-plane band pass filter synthesis. The experimental result show that the insertion loss is less than 3 dB, and the center frequency is 93 GHz with a bandwidth of 2 GHz and the suppression is greater than 42dB near 88 GHz, which means the fifth harmonic (near 78 GHz) of the six frequency multiplier (operating at 94 GHz) are suppressed effectively.