When I decided to retire, I took a few pictures of my last work areas. I was an applications engineer for Analog Devices' RF products group. I tested parts from MHz to 100 GHz.
Here was one of my last test benches, but I don't think the product was mine. By this time, I was responsible for beam forming products. This looks like a GaN ampllifer - you can tell by the monster capacitor on the test board. Those things needed to be pulsed and the drew a ton of current, so you needed a massive cap to be able to supply that current quickly.
It was probably this 1-22 GHz amp: https://www.analog.com/en/products/adpa1112.html
The labs I worked in typically had 50 or 60 test benches like this. Here is one "chase" with about 10 test benches/racks in it. The floor is conductive (as are the chairs) for ESD purposes. You can see a temp chamber on the left. We used to have to characterize our parts from -40 degrees to +85 degrees Celsius. The plexiglass box/cover is there because we had to pump in Nitrogen to prevent frost/freezing.
This was one of our workhorses in the test lab. As you can see if you can zoom in, this box could test from 2 Hz to 110 GHz with extraordinary dynamic range. Cabling was extremely important with these test boxes. Some of our cables cost upwards of $12,000 each. My understanding of using cables capable of cleanly transmitting high frequency signals is why is am a bit biased against a lot of the audio cable debates... audio (Hz to maybe 16 kHz if you're lucky) is a piece of cake to conduct compared to the signals I used to have to worry about.
BTW - I took this picture to show to the Keysight rep.
Those calibration stickers have to be redone every year in a special cal lab.