WR-90 Coaxial to Waveguide Adapter, 8.2 to 12.4GHz
Manufacturer's part number :
The Keysight X281C adapter transforms waveguide transmission line into 50-ohm coaxial line. Power can transmitted in either direction, and each adapter covers the full frequency range of its waveguide band with SWR less than 1.3.
Quote and availability