Rectangular waveguide band-pass filter with high power harmonic suppression

An improved structure of rectangular waveguide band-pass filter with harmonic suppression is proposed. The filter consists of cascade resonant cavities with coupling provided by irises. This article mainly introduced the principle of capacitance loading restrain parasitic passband, the stop-band was successfully pushed to a two octaves frequency range. The results show that the designed rectangular waveguide band-pass filter has a pass-band of 4.4 GHz-5 GHz and stop-band suppression of greater than 70 dB over the frequency range from 6 GHz to 18 GHz, its pass-band insertion loss is less than 0.2 dB, return loss is more than 20 dB. The filter can be used in modern communication systems with the requirement of harmonic suppression.