AlGaN/GaN HEMT X-Band Frequency Doublers with Novel Fundamental Frequency Reflector Scheme

Younkyu CHUNG  Kevin M.K.H. LEONG  Tatsuo ITOH  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.8   pp.1416-1421
Publication Date: 2003/08/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter Wave Technology)
Category: 
Keyword: 
frequency doubler,  AlGaN/GaN HEMT,  active integrated antenna,  conversion gain,  

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Summary: 
The first implementations of X-band AlGaN/GaN HEMT single-ended frequency doublers are presented in this paper. Two types of fundamental frequency signal reflector schemes have been demonstrated for the frequency doubler application. Open-circuited quarter-wavelength microstrip line at the fundamental frequency is utilized for the reflector in a conventional way. In the other architecture a printed antenna is employed as a radiator as well as a novel fundamental frequency reflector. A microstrip rectangular patch antenna operating at the second harmonic frequency of the doubler was designed and integrated with AlGaN/GaN HEMT based on active integrated antenna design concept. Using AlGaN/GaN HEMT with 1 mm gate periphery, two 4 to 8 GHz frequency doublers were designed by the described design methodologies, fabricated, and tested. For the conventional frequency doubler, a conversion gain of 0.6 dB and with an output power of 15 dBm was observed. A conversion gain of 5 dB and an output power of 25 dBm with embedded antenna gain were achieved at a drain voltage of 12 V for the doubler integrated with the patch antenna.