Pulsed microwave field detector - has transistor with polarisation circuits at each terminal, tuned circuit in base and indicator circuit in collector

摘要

A microwave field detector is used, the microwaves being modulated by pulses. It comprises a hypofrequency transistor whose three electrodes are each connected to a polarisation circuit. The base (14) is connected also to an integrated circuit tuned to a neighbouring frequency to that of the microwave field. The collector (15) is connected also to an indicator circuit whose time instant is high compared with the pulse repetition frequency. The base polarisation is fixed near the optimum value at which the transistor and the tuned base circuit presents the maximum selectivity at the frequency of the field. The collector polarisation is fixed in order to obtain an impedance which provides good coupling with the antenna, thus, at the minimum level of detector functioning, the power injected into the transistor produces a maximum excursion of the semicontinuous perentials of the transistor's electrodes.