RC Filter Design for Wireless Power Transfer: A Fourier Series Approach

TL;DR

This paper presents a Fourier series-based analytical framework to understand and optimize the impact of RC filters on wireless power transfer systems, balancing bandwidth and ripple effects.

Contribution

It introduces a closed-form analytical method for designing RC filters in wireless power transfer, improving performance understanding and optimization.

Findings

Closed-form expressions for rectifier output voltage and RC filter output.

Analytical characterization of RC filter impact on WPT performance.

Guidelines for RC filter design in WPT systems.

Abstract

In this letter, we study the impact of the low-pass resistor-capacitor (RC) filter on radio frequency (RF) wireless power transfer (WPT). The RC filter influences both the RF bandwidth by removing the harmonics as well as the ripple voltage at the output of the rectifier. In particular, a large (small) RC time constant, reduces (increases) the ripple but decreases (enhances) the direct-current (DC) component. By following a Fourier series approach, we obtain closed-form expressions for the rectifier's output voltage, the RC filter's output as well as the DC voltage. Our analytical framework provides a complete characterization of the RC filter's impact on the WPT performance. We show that this complete and tractable analytical framework is suitable for the proper design of the RC filter in WPT systems.