A Novel Design of Dual-Band Inverse Class-F Shunt-Diode Rectifier for Energy Harvesting

This brief presents a compact and high-efficiency dual-band (DB) rectifier with a novel implementation of a DB inverse class-F (class-F
⁻¹
) harmonic termination incorporated with a DB fundamental matching network for energy harvesting (EH). Specifically, the harmonics of two design frequencies are manipulated properly in the class-F
⁻¹
standard by only five transmission lines (TLINs) with low sensitivity for more precise harmonic termination performance. The DB fundamental matching network is a TLIN-implemented
$\pi $
-type structure which can transform concurrently two arbitrary complex impedances to the
$50\Omega $
standard source. Both two networks are theoretically analyzed and closed-form equations are derived. A prototype using a Schottky diode SMS7621-079LF is fabricated and measured at 2.4 GHz and 3.5 GHz showing that the highest power conversion efficiency (PCE) is achieved at 64.5% for 2.32 GHz and 64.2% for 3.48 GHz with an input power of 5 dBm and load resistor of
$680\Omega $
while having a compact dimension of 40mm
$\times23$
mm, which indicates advantages of compactness and high PCE, as compared to the existing designs.