Here you can find some interesting designs for 24 GHz
Omni antenna, used for the PA0EHG 24 Ghz beacon for many years
24 GHz feed for an offset antenna with F/D of 0.6
Dual band high performance 10/24 GHz feed
making power 12 Watt output using a Hughes 18 GHz instrumentation TWT
The Microwave Activity Group is stimulating home build activities for 24 GHz.
An easy way to build equipment for 24 GHz is to start with DB6NT designs which have proven to work well.
Information on these designs can be found in DUBUS or via DB6NT: