A Capacitively Coupled Waveguide Filter with Wide Stop-Band

Concept, design and results of waveguide filter with improved stop-band performance are presented. The usual spurious pass bands of standard waveguide filters are suppressed incorporating low-pass filter structures into the coupling elements of the filter. Both a two and three resonator filters have been designed at 35 GHz. With the three resonator filter, a harmonic frequency rejection of (theoretically) more than 120 dB can be achieved.