A Comparison of GaN Class E Inverter and Synchronous Rectifier Designs for 13.56 MHz, 27.12 MHz and 40.68 MHz ISM Bands

A comparative study of class-E inverter and synchronous rectifier designs is made for wireless power applications operating in the 13.56 MHz, 27.12 MHz and 40.68 MHz frequency bands. All the designs use the same GaN switch, gate driver, and PCB layout to provide a consistent reference for comparing the performance of the different designs. The synchronous rectifier circuits are designed as circuit duals of the inverters using the theory of time reversal duality. A comparison of power efficiency is made for different frequency bands as well as for the inverter and rectifier duals. The results show that the inverter and rectifier duals are well matched in terms of efficiency.