This paper presents a collaborative optimization method for the design of wideband transistor-based rectifiers with a large input power dynamic range, targeting high-power energy harvesting and wireless power transfer applications. The core of the proposed method is to establish the relationship between the rectification efficiency, the continuous mode parameter,andthe input power range at several representative frequencies ofthecontinuous class-B/J mode, from which the target load impedance range under different frequencies and power levels is obtained. With the target impedance identified, an Ivy algorithm (IVYA)-driven intelligent optimization framework is then employed to enable the automated design and optimization of subsequent circuit topologies. To verify the proposed method, a wideband transistor-based rectifier operating from 2.2 to 2.6 GHz is designed, fabricated, and measured. The prototype achieves a peak efficiency of 63.5%–76.3% within the operating band, and maintains above 50% efficiency at a 17 dB input power back-off level, demonstrating the effectiveness and applicability of the proposed collaborative optimization method in the design of high-performance rectifiers.

In this article, the analysis of a series of continuous inverse modes power amplifiers (PAs) with resistive-reactive is presented under the impact of input nonlinearity. Theoretical analysis manifests that, different from the conventional extended series of inverse continuous modes (ESCIMs), where the source second harmonic is short-circuited, the second harmonic generated by input nonlinearity can promote and maintain the performance of PAs over a wide frequency band within a flexible impedance range. Furthermore, in the presence of input nonlinearity, a new load design space is reshaped and combined with the source second-harmonic manipulation space generated by input nonlinearity to collaboratively achieve optimal ESCIMs PAs performance. Subsequently, based on the proposed design theory, an ultra-wideband PA is designed, implemented, and fabricated using a two-stage cascaded square ring stub-loaded resonator microstrip bandpass filter architecture with wideband response and a commercially available 10-W gallium nitride (GaN) device. The measurement results show that in the frequency band range of 0.4-4.0 GHz with a relative bandwidth of 160%, a drain efficiency of 55.3-73.8%, an output power of 38.9-41.9 dBm, and a gain of 8.9-11.9 dB have been achieved under saturated output power. Measurement results confirm the theoretical findings reported in this paper.

This paper presents a novel methodology for enhancing rectification efficiency through a transistor-based rectifier design. Here the input second harmonic component at the gate node is employed to modify the output drain current waveforms, thus having a positive effect on the rectification efficiency. A parameter is introduced to evaluate the input second harmonic component, while theoretical analysis is conducted using the class-F operation mode. Further, the relationships between rectification efficiency, drain current, and the input second harmonic component, power ratio, and conductance angle are theoretically derived in detail. Through the appropriate selection of the input second harmonic component, the rectification efficiency can be significantly enhanced. To validate the proposed strategy, a class-F rectifier based on a GaN transistor operating at 2.45 GHz is designed, fabricated, and tested. Measurement results demonstrate a peak rectification efficiency of 90.7% with a dc load of$87 \Omega $and an input power of 40 dBm. The rectifier implemented here exhibits state-of-the-art performance for rectification efficiency compared to other transistor-based rectifiers.

This paper proposes a technique which allows quadband impedance matching and impedance level shifting Doherty power amplifier (DPA) design. By using novel coupler networks with reactance and choosing appropriate complex load impedances, the quadband DPA can reach a power back-off range (OBO) of over 9 dB. In addition, the peak PA branch and the carrier PA branch use different coupler network parameters in order to satisfy different impedance requirements. To illustrate the design procedure a quadband DPA with 9 dB OBO operating in 0.5-0.7 GHz, 1.5-1.7 GHz, 2.5-2.7 GHz, and 3.5-3.7 GHz frequency ranges is designed, fabricated and tested. Measurements demonstrate that the DPA can deliver saturated output power between 43.1 dBm and 43.8 dBm in all four bands, with a drain efficiency ranging from 63.3% to 66.5%. Also, drain efficiency of from 42.2% to 52.3 % can be obtained at an OBO of 9 dB level. The DPA implemented here shows state-of-the-art performance for OBO under quad-band operation.