A Novel MEMS Microwave Power Detection Chip Based on Multibeam Structure

In order to effectively improve the sensitivity performance of micro-electromechanical system (MEMS) microwave power detection chips, a MEMS microwave power detection chip based on a multibeam structure is proposed in this work. A four-beam parallel structure is designed, and the output capacitance of the chip is increased, thereby enhancing its sensitivity. The risk of collapse associated with excessively long single beams is also mitigated, reducing the occurrence of adhesion. The sensitivity and microwave performance of the chip have been theoretically studied, and the chip has been fabricated and measured. Measured results show that in the range from 8 to 12 GHz, the results of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S}_{{11}}$ </tex-math></inline-formula> range from −18.5 to −15.3 dB, while the theoretical results range from −26.8 to −25.2 dB. The reflection ratio deviation of input power is 1.2%. The measured results of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S}_{{21}}$ </tex-math></inline-formula> range from −3.6 to −3.4 dB, while the optimized theoretical results range from −3.42 to −2.27 dB, with an error of 1.8% between them. The measured sensitivity of the chip is 72.76 fF/W, while the theoretical value of the model is 73.5 fF/W, resulting in an error of only 1.01%. Compared to existing structures, the four-beam parallel structure achieves a sensitivity improvement of up to 38.9 times at its maximum and 1.4 times at its minimum. Therefore, the MEMS microwave power detection chip based on a multibeam structure proposed in this work provides a valuable reference for improving sensitivity performance.