Thin-film thermoelectric transducer for accurate measurements of power between 0 and 6 GHz

The paper describes a thermal convertor mounted in a 75 ¿ coaxial line, which consists of two thin resistance films heated by the electric current being measured, with a thin-film thermocouple attached to the midpoint of each resistance film to give the temperature rise at the point. Both the heater and the thermocouple are depostited on a sustrate and insulated from each other; thus it is decribed as an `indirectly heated thermocouple¿. It was found that the device could be calibrated in terms of d.c. power dissipation and give measurements of power in the range ¿25 to +22dBm with an accuracy of within ±2% at frequencies of 0¿1GHz. Morever, comparison of the performance of the thin-film theormoelectric element with other power measuring instruments indicates that it is of acceptable accuracy, even at microwave frequencies up to 6GHz.