Pandhuan gelombang transisi WR28-WR22 30.0-40.0 GHz 25.4mm Pandhuan gelombang transisi WR4-WR5 140-260 GHz 25.4mm Pandhuan gelombang transisi WR28-WR22 140-260 GHz 25.4mm Pandhuan gelombang transisi WR112-WR90 8.2-10GHz 25.4mm WRD750 waveguide bengkong 8-18GHz