Key Specifications. Waveguide Size 1 WR-42 Waveguide Size 2 WR-42 Frequency, Min 20.2 GHz Frequency, Max 21.2 GHz Highband Min Rejection 110. Lowpass Waveguide Filter With WR-42 Interface Operating from 20.2 GHz to 21.2 GHz. The PE-W42F013 is a WR-42 lowpass filter with UG Cover and UG Grooved Flanges. The pass band is 1000 MHz, or 20.2 to 21.2 GHz. Implementing a waveguide design, the filter has excellent rejection of 110 dB minimum at 43.5 to 45.5 GHz, or about 22.3 GHz from the band edge. It has a maximum insertion loss of 0.5 dB.