I need a circuit that will sense a 2 Ghz rf signal and turn off a relay and keep the relay
off as long as the signal is present.
Any suggestions or directions please.
Howie
Howie,
First, welcome.
If I understand your question (and subsequent responses) you might wish to consider this
chip, for starters. Note that it is called a "detector". No doubt there are simpler solutions. This is just the first datasheet option I came across when I googled "schottky diode 2GHz to 3GHz".
By carefully constructing your 1/4λ antenna to 2Ghz (≈3.75cm in length) you could roughly "tune" the circuit to your 2Ghz signal. It would still respond to other frequencies, but not as well. Plus the power level of your transmitter, as well as the range from transmitter to receiver chip antenna, would be critical factors in overall operation.
As this chip will only provide a max of a 2mA output pulse, you'll need a buffering circuit to turn off a relay as you describe.
Ghpilot said:
All I want to do is sense an rf signal in the 2 Ghz range,then switch a relay.
Why do I need a receiver? This isn't a communication project.
But you are, in fact, detecting (
receiving) a signal, are you not, that hopefully, once "sensed" will be "communicated" as an "OFF" command to the relay, right? Simple, to be sure, but communications nonetheless.