A Compact and High-Efficiency Design of Triple-Band Rectifier With Harmonic Suppression for Wireless Power Transfer

In this letter, a triple-band (TB) rectifier with a novel harmonic control network is presented. This rectifier exhibits improved power conversion efficiency (PCE) for wireless power transfer (WPT) at three arbitrary frequency bands ranging from a few hundred megahertz to 10 GHz. Specifically, the harmonic suppression network (HSN), consisting of five microstrip transmission lines (TLINs), accurately suppresses the TB second harmonic with infinite impedance, based on theoretical analysis derived from closed-form equations. For verification, a prototype using a Schottky diode BAT15-03W is simulated and measured at three target frequencies of 0.915, 2.45, and 5.8 GHz. In the measurements, the rectifier exhibits a reflection coefficient
$S_{11}$
of
${ < }{-}15$
dB, corresponding to the highest PCE of 79.5%, 74.8%, and 68.7% at 0.86, 2.35, and 5.78 GHz, respectively, with input powers of 10, 11, and 13 dBm. Additionally, the rectifier has a compact dimension of
$32\,\, {}\times {}39~\text {mm}^{2}$
. To the author’ best knowledge, a TB HSN is implemented for the first time in the TB rectifier design.