My 24 GHz radio is based on an Endwave SDH module. These modules became available on eBay in about 2007. They were originally used in Europe in point-point microwave links. With minor modifications they can be used as 24 GHz transceivers with excellent performance.
In addition to the SDH module, I machined a rotary waveguide switch which is actuated by a hobby servo controlled by an Arduino microcontroller.
The waveguide switch machined using a combination of traditional vertical milling as well as wire electrical discharge machining (EDM).
The final main RF components consist of a combination of a Reactance Labs OpenSynth 3000 PLL synthesizer and a TimesFour prototype board. Together they generate a 12.024 GHz tone that is multiplied in the SDH unit for the LO.
An ovenized 10 MHz crystal and multiple switching voltage regulator unit comprise the rest of the electronics.
The antenna is a surplus MA/COM 12″ parabolic antenna. The entire radio is mounted on my multi-band tripod along with the 47 and 79 GHz radios.