对称式微波功率传感器的设计

Design of symmetrical microwave power sensor

为了克服传统微波功率传感由于失配和热损耗带来的微波功率测量误差,提出了一种基于MEMS技术的对称式微波功率传感器,对该微波功率传感器的微波损耗、温度分布以及微波功率的精确测量进行了研究。首先,根据提出的损耗模型推导了微波损耗功率和损耗电压的表达式,并建立了该传感器的传热解析模型;接着,设计并制作了该微波功率传感器;最后,对该功率传感器的补偿因子、灵敏度和频率依赖特性进行了测试和分析。测试结果显示:该传感器在5,10,15 GHz频率下的补偿因子分别是1.56,2.12和2.56 dBm,灵敏度可达到0.18 mV/mW,输出电压与微波频率的相对偏差<2%。结果表明,对称式微波功率传感器可通过测量直流功率来实现测量微波功率的目的,且明显地提高了微波功率测量的精确度。

In order to overcome the measurement errors of traditional microwave power sensors due to mismatch and thermal losses,a symmetrical microwave power sensor based on the Micro-electro-mechanical System（MEMS） was proposed and its microwave loss,temperature distribution and the accurate measurement were researched.Firstly,expressions of the loss power and loss voltage were derived according to the proposed loss model,and the heat transfer analytical model of the power sensor was established.Then,the sensor was designed and fabricated.Finally,the compensation factor,sensitivity and the frequency-dependent characteristics of the power sensor were measured and analyzed.The measurement results show that the compensation factor of the power sensor at 5,10 and 15 GHz are 1.56,2.12 and 2.56 dBm,respectively.The sensitivity is about 0.18 mV/mW,and the relative difference of the output voltage with the microwave frequency is below 2%.It is concluded that the symmetrical microwave power sensor can measure the microwave power by measuring the DC power,and also can improve the measurement accuracy of the microwave power significantly.