A Matched-Load Type Thermoelectric Transducer for Power Measurements in the Millimeter-Wave Region

As a power detector in the millimeter-wave region, a matched-load-type thermoelectric transducer is proposed. Experimental investigations have been carried out to obtain the design criteria of this device. The investigations have two aspects. One of them is macroscopic and related to the matching characteristics of the transducer. The other is microscopic and related to the sensitivity characteristics. The analysis of the temperature distribution on the power-sensing element is the main problem in the latter respect. Through these investigations, tentative design criteria have been obtained. Transducers manufactured on the basis of these criteria have shown excellent performance as practical millimeter-wave power detectors. Outstanding characteristics of this device are low VSWR and small deviations of the sensitivity in the entire waveguide frequency band. The stability of this device over long periods of use was also confirmed.