Study on the Second-Order Vibration Model of Dual-Channel Microwave Power Detection Chip

To improve the efficiency and accuracy of the capacitance detection channel, the motion process of the cantilever beam during microwave power detection is systematically investigated. A comprehensive analysis of the cantilever beam’s motion behavior is conducted, leading to the proposal of a second-order vibration model that examines displacement variations at the moment of microwave signal input from both static and dynamic perspectives. Furthermore, an equivalent circuit model is proposed to explore the microwave characteristics of the microwave power chip. The overload power and sensitivity are also analyzed, contributing to the trade-off optimization of the chip design. Tests are carried out on chips with three different cantilever beam sizes. In the X-band, all chips exhibit a return loss below −10 dB, with the lowest return loss recorded at less than −10.3 dB, demonstrating excellent microwave performance. At an input frequency of 10 GHz, the sensitivity of the three chips is measured at 16.3, 65.6, and 144.4 fF/W, while the theoretical sensitivity of the model are 3.5, 46.5, and 215.9 fF/W, highlighting the high detection sensitivity of the chips. These findings provide valuable insights for the design of micro-electro-mechanical system (MEMS) microwave power chips.