Broadband - microwaves power detector, the diodes, above its resonant frequency is used

摘要

A microwave power sensor is disclosed which is capable of using diodes above their resonant frequency to sense the power of input microwaves. The power sensor includes a sensing diode, a conditioning means, and a tapered waveguide. For input waves having frequencies near and above the resonant frequency of the sensing diode, the output of the diode begins to be frequency dependent. That is, the diode outputs different DC signals for waves having different frequencies even though the power of the waves is the same. The conditioning apparatus is adapted to offset the frequency dependence of the diode by varying the fraction of the input wave that is transmitted to the diode so as to cause the output of the diode to be relatively constant for waves having equal power but different frequencies. The conditioning apparatus also provides a load impedance which matches the characteristic impedance of the input wave to minimize the reflection of the input wave. In addition, the conditioning apparatus attenuates the input signal to ensure that the sensing diode operates in the square law region. The tapered waveguide receives the wave transmitted by the conditioning apparatus and conveys it to the sensing diode. The waveguide is adapted to cause the input wave to have a voltage maximum at its output port. By attaching the sensing diode across the output port of the waveguide, the power sensor is capable of sensing the power of input waves having frequencies over a broad frequency band.