The Agilent Q281A is a 2.4 mm female to WR-22 waveguide adapter that operates in the 33 to 50 GHz frequency range. These adapters transform waveguide transmission lines into 50 ohm coaxial lines. Power can transmitted in either direction, and each adapter covers the full frequency range of its waveguide band with SWR less than 1.3.
HP / Agilent Q281A