Radar and Microwave Systems
This is the simplest form consisting of a single radar antenna serves both the microwave source or transmitter and the receiver.
The signal is transmitted into space. If no object is present, then the signal continues to propagate, and no reflection is received.
If a target comes into range, the energy is reflected and this backscatter energy is propagated back to the receiver.
A detector, which can be a simple microwave diode device or a more complex circuit, demodulates (rectifies) the received signal.
This signal is then amplified and filtered before being applied to a threshold detector. If the signal is above the set threshold, then the system declares a detection and passes a signal to the output.