I understood idea behind speed radar, i found all equations.
But i dont know where to start. how to build 10GHz microwave transceiver and receiver , then how to make frequency maching (difference finding circuit) …
After I find difference I can do processing or find speed in microcontroller.
I will be happy if you can suggest any link or any idea or any useful information
Thank you very much :?: :lol:
If you really want to work at 10 Ghz inexpensively, look into buying a used x-band gunn diode oscillator on Ebay. Then read up on feed-horns formulas and make one out of aluminum foil covered cardboard, sheet metal from home depot, Sears tool store etc. Minicircuits sells inexpensive parts of which some are rated to 10 Ghz; and also sometimes show up on Ebay. here’s a link to simple gun(n) diode control circuit:
There are some GUN diode base Gunplexers available in 10 * 24GHz but you’ll need to look around for them.
Microwave Associates is one source. Google to find more about them.
A Gunplexer can receive as well as transmit. The receive output is the difference between to frequency of the received signal and the frequency of the Receiver. If both the transmitter and receiver are tuned to the same frequency the any Doppler of the transmitted signal is directly output from the receiver.
Some auto-matic door openers use Gunplexers so this could be a cheap source.
You would have to pay to read it, but the Australian magazine “Silicon Chip” had an article a few years ago about making your own radar gun:
I have built my own X-band doppler radar using an old gunn-diode module designed originally for door-openers and security systems.
It works satisfactorily up to about 200 yards on vehicle-sized objects but the thing I noticed immediately is that because the mixer/detector diode is in the same cavity as the oscillator diode, the signal that comes directly from the gunn diode tends to saturate the mixer, reducing the sensitivity significantly.
If you want to get better range (which is possible) then you need to make separate receive and transmit horns and cavities – adjusting the amount of oscillator leakage to set best sensitivity and lowest-noise at the mixer diode.
Doing that you can extend the range by a significant amount.
Unfortunately these old gunn-diode-based modules are becoming increasingly difficult to find these days.