Optimization of spread-spectrum MSK sequences and passive, multi-resonant bandpass rectifiers for wireless power transfer with low electromagnetic interference

This paper addresses the concern for both electromagnetic interference (EMI) and human RF exposure in wireless power transfer (WPT). In many applications like medical, portable, and wearable devices, RF exposure is a greater concern, and the unrestricted ISM bands are often not optimal. Outside of the ISM bands, the restrictions on transmitter power are onerous. The computer-aided design of appropriate spread spectrum sequences to drive WPT and the associated bandpass rectifiers is presented. The sequences are optimized for a new four-quadrant inverse class D amplifier using a genetic algorithm. The wireless power is captured by a high order bandpass rectifier that is optimized using a surrogate model to alleviate the computation cost of performing time domain simulations.