基于单片式微波集成电路的终端式MEMS微波功率传感器

摘要

提出了一种基于塞贝克效应的终端式MEMS微波功率传感器,该传感器的制作工艺与GaAs单片式微波集成电路(MMIC)工艺兼容.利用热电偶检测温度差,生成与微波功率成比例的直流电压,由GaAs/Au热电偶串联构成热堆.传感器将电功率转化为热,再间接测量热堆生成的直流电压.采用微机械加工技术,去除了器件底部的GaAs衬底,从而减小了热损耗和电磁损耗,提高了灵敏度.测试结果表明,在0～20 GHz内,HFSS模拟的S11＜-22 dB;测试输入功率为-20～20 dBm时,频率为0～20 GHz;在20 GHz时,灵敏度高于0.15 mV/mW;在整个频率范围内,回波损耗低于-26 dB.%On the basis of the Seebeck effect,a terminating type MEMS microwave power sensor fully compatible with the GaAs Monolithic Microwave Integrated Circuits(MMIC) process is presented. A thermocoupler in the microwave power sensor is used to detect the temperature difference and to generate a DC voltage proportional to the microwave power. Then, a series of GaAs/Au thermocouples make up a thermopile. The sensor based on a simple principle converts the electric power into heat and the DC voltage produced by the heat is indirectly measured,so that the output microwave power can be obtained. Moreover,in order to minimize the thermal and electromagnetic losses, the bulk GaAs located beneath the device is removed through micromachining. As a result, the sensitivity of the sensor is improved. Tested results show that the HFSS simulation of S11 is less than -22 dB when the sensor measures the microwave power from -20 dBm to +20 dBm. The sensor sensitivity is higher than 0.15 mV/mW at 20 GHz, and the input return loss is less than -26 dB over the entire frequency ranges.