WR28-WR22 shanduko yewaveguides 30.0-40.0 GHz 25.4mm WR4-WR5 shanduko yemafungu 140-260 GHz 25.4mm WR28-WR22 shanduko waveguides 140-260 GHz 25.4mm WR112-WR90 shanduko waveguides 8.2-10GHz 25.4mm WRD750 yakamonyoroka waveguide 8-18GHz