Application of AlGaAs/GaAs HBT's to Power Devices for Digital Mobile Radio Communications

Norio GOTO  Nobuyuki HAYAMA  Hideki TAKAHASHI  Kazuhiko HONJO  

IEICE TRANSACTIONS on Electronics   Vol.E76-C   No.9   pp.1367-1372
Publication Date: 1993/09/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Heterostructure Electron Devices)
bipolar transistor,  heterojunction,  power amplifier,  digital mobile communication,  power efficiency,  

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This paper describes the performance of AlGaAs/GaAs HBT's developed for power applications. Their applicability to power amplifiers used in digital mobile radio communications is examined through measurement and numerical simulation, considering both power capability and linearity. Power HBT's with carbon-doped base layers showed DC current gains over 90. A linear gain of 19.2 dB, a maximum output RF power of 32.5 dBm, and a power added efficiency of 56 percent were obtained at 950 MHz. Numerical simulations showed that the power efficiency of HBT amplifiers could be improved by using harmonic trap circuits. Intermodulation measurements showed that third-order distortions were at most 21 dBc level at the 1-dB gain compression point. RF spectrum simulations using π/4 shift QPSK modulation showed that side-band spectrum generation was less than 45 dBc level at points 50 kHz off of the carrier frequency. These properties indicate that the power handling capabilities and linearity of HBT amplifiers offer promising potentials for digital mobile radio communications.