Application of the magnetoresistance effect in semiconductors to microwave power measurements

Theoretical and experimental investigations have been made on the application of the magnetoresistance effect in semiconductors to the measurement of microwave power. Five magnetoresistance microwave wattmeters of different kinds, with InSb or InAs elements, were constructed. Various measurements were taken, at 10 or 34Gc/s, to investigate the existence of the multiplying action between the electric- and magnetic-field components of the wave by the magnetoresistance effect, varying the magnitude and phase of the current through the element by means of an adjustable coaxial piston. All the measurements showed a qualitative agreement with theory. A direct voltage output across the element, resulting from the multiplying action of the magnetoresistance effect, was observed for each wattmeter, and, when suitable phasing adjustments had been made, was found to bear a good linear relationship to the microwave power in the guide, reversing its polarity with a reversal of the direction of the bias magnetic field.