Design and analysis of a terahertz bandpass filter

In this paper, a terahertz waveguide filter using micromechanical milling process is designed and fabricated. The filter is designed at 255 GHz with a 3dB bandwidth of 30 GHz. The measured results show that the return loss is better than 15 dB and the insertion loss is about 3.9 dB at center frequency, good agreement between the measured and simulated results is achieved. In addition, the main loss of the terahertz passive components fabricated by micromechanical milling process is also analyzed. A 25mm waveguide is also fabricated and the unit length loss of the waveguide is about 0.16 dB/mm at 400 GHz.