Citation

Yusof, Khairul Hilmi and Zubir, Farid and Rahim, Mohamad Kamal A. and Kumar, Narendra and Rajendran, Jagadheswaran and Md Jizat, Noorlindawaty and Gardner, Peter and Johnson, Thomas (2025) Systematic Design of a Compact Lumped-Element Outphasing Class-E Power Amplifier for HF Band. IEEE Access, 13. pp. 161116-161133. ISSN 2169-3536

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Abstract

This paper presents a novel design methodology for an outphasing Class-E power amplifier operating at 27.12 MHz, specifically addressing limitations inherent to traditional outphasing combiners that utilize distributed microstrip transmission lines for harmonic termination. At MHz frequencies, conventional microstrip techniques become impractical due to excessively large physical dimensions. To overcome this, the proposed design employs an entirely lumped-element combiner network, eliminating the need for distributed microstrip harmonic terminations. A rigorous analytical framework is derived using two-port impedance matrices, ensuring simultaneous impedance matching at both peak and back-off power conditions. Parametric studies optimize component values, resulting in enhanced efficiency and stable output power across a broad range of outphasing angles. A prototype employing GaN-based transistors demonstrates high efficiency of 73.2% at peak output power and maintains above 50% efficiency at 6 dB output back-off, validating the effectiveness and practicality of the proposed lumped-element approach. This compact and efficient configuration offers significant advantages for MHz-band RF transmitters and wireless power transfer systems.

Item Type:	Article
Uncontrolled Keywords:	Class-E amplifier, high efficiency, lumped-element combiner, MHz frequency, outphasing amplifier, reactance compensation.
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK5101-6720 Telecommunication. Including telegraphy, telephone, radio, radar, television
Divisions:	Faculty of Engineering (FOE)
Depositing User:	Ms Suzilawati Abu Samah
Date Deposited:	06 Oct 2025 02:48
Last Modified:	06 Oct 2025 04:28
URII:	http://shdl.mmu.edu.my/id/eprint/14679

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