220GHz band-pass filter based on circular resonance cavities with low loss
In this letter, characteristics of the circular resonant cavity are investigated. A waveguide band-pass filter based on four circular resonant cavities is designed through theories of filters with Chebyshev response and fabricated using sophisticated machining. The effect on the loss within pass-band from the gap in the assembling process is analyzed. The measured results is in good agreement with the simulated ones, in which the center frequency is at 219GHz, the 3dB bandwidth is about 9.75GHz and the minimum loss within pass-band is 0.5dB.