Rectangular Waveguide Filters Using Photoimageable Thick-film Processing

Band-pass H-plane offset Rectangular Waveguide filters at W-Band (75-110GHz) and F-Band (90-140GHz) are presented. The filters are designed using multilayer thick-film processing with Alumina as a base. The process incorporates photoimageable thick-film paste for better precision and sharpness at the corners of the offsets. The filters do not require any tuning and are described with regard to their manufacture and measurement results. The centre frequencies are 85GHz and 105GHz and their relative bandwidths are ≈ 10%. The filters are de-embedded using a specially designed calibration set which uses the multiline TRL technique. Insertion loss of 5 dB and return loss less than 15 dB is measured for waveguide thickness of 18μm.