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

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