A polyconductor beam detector

A sensor circuit for the purpose of thermal detection and power measurement of incident microwave and laser beams due to accidental or targeted exposure is described. In this sensor, a polyconductor device acts as a microwave or optical beam absorber. The basic feature of the polyconductor is that its terminal resistance in the transition region can vary by many orders of magnitude with small changes in excitation over a wide frequency range. Thus the heating effect of the incident wave changes the terminal resistance, which in turn is converted into an imbalance of a sensitive Wheatstone bridge circuit with appropriate display. The sensor proved adequate for a wide range of fluctuations in incident power levels and ambient temperature