一种新型MEMS微波功率传感器的理论模型与优化设计

提出了一种新型的MEMS微波功率传感器.与传统的结构相比,新结构具有测量误差小、设计简单、使用方便等显著优点.然后在全面考虑了热传导、热对流、热辐射三种传热机制的基础上,对传感器的主要部分即热电堆建立了热模型,进而导出了灵敏度、时间常数、噪声的理论解析式.最后根据拉格朗日乘数法原理,以给定的时间常数和噪声大小为约束条件,求得灵敏度达最大时热偶长度和串联数目的最佳值.

Analytical Modeling and Optimal Design of A Novel MEMS Microwave Power Sensor

A novel thin-film MEMS microwave power sensor is presented. Compared with the traditional microwave power sensors, this novel sensor has the remarkable advantages of less measurement error, simpler design process, more convenient usage etc. The thermal analytic model of the main part of the sensor, namely the thermopile, is then proposed on the basis of a thermal study of the three heat transfer mechanisms(i.e. conduction, convection, and radiation), and thereby the expressions for the sensitivity, thermal time constant and thermal noise of the thin-film microwave power sensor are deduced. The problem of the optimization of this sensor is solved by using the method of Lagrange multipliers, that is, finding the optimum value of the length and number of the thermal couples in series when the sensitivity reaches maximum value under given value of time constant and noise level.