High-Efficiency and High-Current GaN-Based Microwave Rectifier for Wireless Strain Sensing and Monitoring
Tao Liu, Yang Li, Jiayi Yang, Tingting Wang, Xiao Wang, Lin‐An Yang, Michael D. Dickey, Jin‐Ping Ao, Yue Hao
Abstract
In this article, a gallium nitride (GaN) Schottky barrier diode (SBD)-based microwave rectifier with high efficiency, current, and power bandwidth is proposed for wireless strain sensing and monitoring. Solutions including semiconductor devices, rectification circuits, and sensing mechanisms are discussed. A microwave rectifier working at 928 MHz is designed for wireless rectification strain sensing, with a measured power efficiency over 85% and a load resistance lower to 40 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> based on a customized quasi-vertical GaN SBD. The finger layout and TiN anode make the SBD series resistance reduced to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.81~\Omega $ </tex-math></inline-formula> , but saturation current enhanced to 11.8 nA, which significantly reduces rectification loss when the load resistance is small. Finally, a rectification strain sensor (RSS) is proposed by dielectric coupling the rectifier and a piezo-permittivity liquid metal elastomer foam (LMEF), with a measured relative output power variation and wireless working distance over 437%/mm and 3 m, respectively.