Research on the Response Time of Indirect-Heating Microwave Power Sensor

Abstract

This paper mainly presents the response time with different parameters to study the dynamic response characteristic of indirect-heating thermoelectric microwave power sensor in order to provide reference for numerous practical applications. The fabrication of thermoelectric power sensor is compatible with the microelectromechanical systems technology and GaAs microwave monolithic integrated circuit process. An equivalent model of a typical thermoelectric power sensor is proposed to briefly analyze the thermal time constant in cooling process and theoretically predicted trends are nearly in accordance with the measured fall time when the membrane has nearly the same length of the thermopile. Measurements indicate that the response time does not change obviously with the incident power and ambient temperature, and increases with the length of thermopile and distance between resistors and thermopile. When the length of thermopile is 100 μm and distance between resistors and thermopile is 10 μm, the rise time and fall time of power sensor under normal ambient temperature 300 K are 1.06 and 0.37 ms, respectively. Furthermore, the return loss and the output voltage are measured with a large incident power to characterize the performance and study the failure phenomenon of the power sensor. The obtained burn-out power of the power sensor is ~1.1 W.