A RF power detector circuit for detecting radiation power of emitting antennas with directional characteristic can be designed using electronic scheme from the figure below. This RF power detector circuit allows the user to adjust the radio frequency antenna accuracy for optimal transmission of radiation.
An auxiliary antenna must be positioned a short distance from the main emitting antenna. Signal that is then applied to a resonant circuit formed by L1, L2 and variable capacitor C2. This allows the instrument to be perfectly tuned to specific emission frequency to be measured. The values given in the coil circuit diagram, the bandwidth of the instrument is 6 ... 60 MHz.
RF signal is applied to diode D1, which forms a floor recovery / demodulation. Noninverting input signal is driven by the operational amplifier IC1. Operational amplifier gain and sensitivity of this instrument of 1 mA, are adjusted with the potentiometer P1.