A Compact and High-Efficiency 0.915/2.45/5.8 GHz Triple-Band Rectifier With Harmonic Suppression Based on Coupled Transmission Line

In this brief, for the first time, a novel methodology for designing a compact and high-efficiency triple-band (TB) rectifier is presented for wireless power transfer (WPT) and energy harvesting (EH) at industrial, medical, and scientific (IMS) bands, i.e., 0.915 GHz, 2.45 GHz, and 5.8 GHz. Specifically, the proposed structure uses a coupled transmission line (CTL) connected in shunt at the diode anode to suppress the second harmonic of three frequencies concurrently while adopting well with a TB fundamental matching network, enabling an efficient TB power recycling mechanism for efficiency enhancement with a miniature size. The CTL operation is investigated in the closed-form equations. For validation, a Schottky diode-based rectifier is simulated, fabricated, and measured. The experimental results show that peak power conversion efficiency (PCE) is achieved at
$79.97~\%$
,
$74.58~\%$
, and
$73.62~\%$
for 0.895 GHz, 2.37 GHz, and 5.57 GHz, respectively. Moreover, the
$50~\%$
over PCE remains within a wide dynamic range of 18.5 dB at 0.895 GHz, 17 dB at 2.37 GHz and 17.5 dB at 5.57 GHz. Compared to other works, the proposed rectifier exhibits advantages of high PCE and compactness.