WR19 rectangular waveguide terminal matched load 40-60GHz 28-31GHz waveguide Harmonic Bandstop Filter WR15 rectangular waveguide terminal matched load 50-75GHz Hexagon bar wrench Allen key WR430 Waveguide Switch 1.72~2.61GHz WR90 standard welded waveguide flange WR15 rectangular waveguide terminal matched load 50-75GHz WR19 rectangular waveguide terminal matched load 40-60GHz WR22 rectangular waveguide terminal matched load 33-50GHz WR22 waveguide-coaxial adapter 33-50GHz WR28 waveguide-coaxial adapter18-26.5GHz