Class-F GaN HEMT Amplifiers Using Compact CRLH Harmonic Tuning Stubs Designed Based on Negative Order Resonance Modes

Shinichi TANAKA  Sota KOIZUMI  Ryo ISHIKAWA  Kazuhiko HONJO  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E102-C   No.10   pp.691-698
Publication Date: 2019/10/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.2019MMP0001
Type of Manuscript: Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technologies)
Category: 
Keyword: 
left-handed metamaterials,  power amplifier,  

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Summary: 
Extremely compact harmonic tuning circuits for class-F amplifiers are realized using composite right-/left-handed (CRLH) transmission line stubs. The proposed circuits take up only a small fraction of the amplifier circuit area and yet are capable of treating four harmonics up to the 5th with a single stub or double stub configuration. This has become possible by using the negative order resonance modes of the CRLH TL, allowing for flexible and simultaneous control of many harmonics by engineering the dispersion relation of the stub line. The CRLH harmonic tuning stubs for 2-GHz amplifiers were realized using surface mounting chip capacitors, whereas the stub for 4-GHz amplifiers was fabricated based fully on microstrip-line technology. The fabricated 2-GHz and 4-GHz GaN HEMT class-F amplifiers exhibited peak drain efficiency and peak PAE of more than 83% and 74%, respectively.