Micromachined WR-3 waveguide filter with embedded bends

Presented is a micromachined WR-3 waveguide filter with two embedded H-plane back-to-back bends fabricated using thick SU-8 photoresist micromachining technology. The filter was constructed with four silver-coated SU-8 layers with a thickness of 0.432 mm for each layer. These layers were then bonded on top of each other to form the filter. This layered WR-3 waveguide filter with bends exhibited a minimum insertion loss of 3.3 dB and an 8.8% 3 dB fractional bandwidth at a central frequency of 293.2 GHz. The measured return loss is better than 16 dB across the whole passband.