Economical compact waveguide band-pass filter with circular posts

With the ever-crowding spectrums in the lower microwave frequency, the need for waveguide filters in communication systems is increasing rapidly due to their low loss and good selectivity. Yet two main factors limiting the use of such filters are their high fabrication costs and big sizes. An economical compact band-pass filter loaded with both inductive and capacitive circular posts has been proposed. The concept, CAD simulated results, and tested results from a sample filter will be presented in this paper. The results show that the sample filter has several advantages, such as low fabrication cost, compactness, light weight, and far away spurious pass-band.