The benefits of using source field plate (FPS) in AlGaN/GaN HEMTs to reduce the phase distortion in efficient power amplifiers (PAs) is demonstrated in this contribution. The link between phase distortion of a PA and the drain -togate feedback parasitic capacitance of the transistor is shown. This link leads to critical phase nonlinearity expecially when architectures based on output load modulation, as the Doherty topology, are adopted. The FPS effect in reducing the feedback parasitic capacitance and, thus, the AM/PM distortion of the PA is verified. For experimental validation two AlGaN/GaN HEMT structures, with and without FPS, are realized and compared in order to extract the effects of FPS. Source-load pull characterizations are performed on both structures in order to verify the benefits of FPS on phase distortion, both in fixed and modulated output load conditions.
Phase Shifted Transmitter (PST) operates without mixers and allows the direct generation and transmission of any envelope and phase-modulated signals. Besides of maintaining all the benefits of the standard PST architecture, the solution here proposed allows the integration of an energy recovery circuit capable to boost the efficiency of the overall transmitter up to 50%. The theoretical analysis of the novel architecture is reported highlighting the relevant differences and advantages with respect to the standard approach. The required key RF blocks have been realized in hybrid technology employing GaN HEMT devices and Schottky diodes to design the power amplifiers (PAs) and the energy recovery circuit, respectively. In particular, the former have been designed by exploiting the 2 nd harmonic tuning approach. Experimental results on the PAs have shown an efficiency higher than 70% at 39 dBm of output power with an associated gain greater than 11 dB at 2GHz. Moreover, a draft experimental validation of the overall system is also reported showing promising performances.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.