WR-137 Waveguide to Coaxial Adapters from Fairview Microwave are also known as waveguide to coax transitions. Type N, SMA waveguide to coaxial adapters are in-stock and available for same day shipment. Fairview WR-137 Waveguide to Coaxial Adapters have a maximum frequency of 8.2 GHz and a max VSWR of 1.25. WR-137 Waveguide to Coaxial Adapters have a body material of aluminum and a connector body material of brass or passivated stainless steel.