Input power detection circuit with a diode
Input power with a diode detector circuit shown, this is a simple half-wave rectifier, filter circuit, the circuit’s total input resistance of 50O. VD for the rectifier, C for the filter capacitor. RF input power PIN is rectified and filtered by the output voltage Uo. Uo at different ambient temperatures and the PIN of the curve shown below. The figure shows, only under the ambient temperature of +25 oC Uo approximately linear relationship with the PIN, when the ambient temperature will increase or decrease significantly reduced when Uo.