This letter presents a novel methodology for designing high-efficiency dual-band (DB) inverse class F (class $\text{F}^{-1}$ ) rectifier for wireless power transfer (WPT) and energy harvesting (EH). Specifically, a proposed DB class $\text{F}^{-1}$ harmonic termination network is employed based on transmission lines (TLINs) which are theoretically analyzed. The closed-form design formulas are derived for providing exact class $\text{F}^{-1}$ harmonic manipulation at two arbitrary frequency bands, enabling a highly efficient DB class $\text{F}^{-1}$ operation. For validation, a Schottky diode-based rectifier is implemented at two target frequencies of 1.9 and 2.45 GHz. The experimental results show that peak power conversion efficiency (PCE) can be achieved over $76\%$ at 1.81 and 2.35 GHz with an input power of $13$ dBm. Moreover, the rectifier exhibits a $>\!\!50\%$ PCE within a wide dynamic range (DR) of $19.5$ and $17.5$ dB at 1.81 and 2.35 GHz, respectively. To the author’s best knowledge, this is the first time a DB diode-based rectifier design with the deployment of a DB harmonic termination mechanism is incorporated with a DB fundamental matching network.

This letter presents the compact and high-efficiency Class-F rectifier with a novel multiharmonic termination network for wireless power transfer (WPT). This network deploys only four transmission lines (TLINs), which allows harmonic control up to the sixth order and provide fundamental input impedance matching, simultaneously; enabling an efficient Class-F behavior. The implemented rectifier exhibits a superior power conversion efficiency of $82.2\%$ at 2.4 GHz for an input power level of 15 dBm, and has a size of $0.24~\lambda\times0.16~\lambda$ , indicating clear advantages in high power conversion efficiency (PCE) and compactness over the other designs.

This letter presents a novel implementation of inverse class-F (class-F $^{-1}$ ) rectifier based on lumped elements for biomedical wireless power transfer (WPT) at 433 MHz. Specifically, in order to reshape the diode current and voltage according to the class-F $^{-1}$ waveform, a parallel LC resonator is deployed at the diode anode as a band-stop filter to provide infinite impedance for the second harmonic. Meanwhile, the third harmonic is terminated with zero impedance by a series LC network at the diode cathode side where its quality factor is also controlled to facilitate the fundamental matching. A prototype is fabricated and measured for verification showing that the peak power conversion efficiency (PCE) is achieved at $72.8\%$ with an input power of $5$ dBm. Also, the proposed rectifier exhibits $\text{PCE}>50\%$ within a wide dynamic range of $22.5$ dB and a compact size of $13\times7$ mm $^{2}$ , which indicates an advantageous performance over the other existing designs with similar diode and frequency.

In this letter, a novel design of high-efficiency dual-band (DB) rectifier based on coupled transmission line (CTL) is presented. The proposed structure is separated into two parts. Part A uses a CTL to suppress the second harmonic of both the frequencies concurrently, enabling a DB-efficient power recycling mechanism with low design complexity and compact dimension. Part B implements a DB fundamental matching network to the source of 50 $\Omega$ with a combination of a CTL and a single transmission line (TL) which also terminates the harmonics beyond the second-order for further power conversion efficiency (PCE) enhancement. Both the parts are investigated in the closed-form equations. For validation, a Schottky-diode-based rectifier is simulated, fabricated, and measured at two frequencies of 0.915 and 2.4 GHz. The experimental results show that the highest PCE is achieved at 81.98% and 77.85% for 0.915 and 2.4 GHz, respectively, with an optimal load resistance of 680 $\Omega$ . Moreover, the 50% over PCE remains within a wide dynamic range of 19.5 dB at 0.915 GHz and 18.5 dB at 2.4 GHz. Compared with the state-of-the-art works, the proposed rectifier exhibits advantages of high PCE and compactness.

In this paper, 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.

This paper presents a novel methodology for designing a rectifier with high efficiency and wide dynamic range (DR). Specifically, the proposed structure employs a combination of two diodes which are optimized for operation at distinct power levels. These diodes are switched automatically according to input power level during rectifying process based on a simple adaptive power distribution (APD) mechanism, which is intimately related to the diode’s input impedance and is mathematically analyzed, for DR extension. In addition, a low-pass two-stage matching network is implemented instead of the conventional matching network for simultaneous fundamental matching and multi-harmonic suppression, enabling an efficient power recycling operation which, as a result, further enhances power conversion efficiency (PCE). A rectifier using two types of the Schottky diode (HSMS2850&HSMS2860) is designed, simulated and measured at 915 MHz for verification. The measured results shows peak PCE of 75.5% at an input power of 9.5 dBm and an enhanced DR of 21.5 dB for PCE> 50% while having a compact size, indicating a superior performance, as compared to other designs.