Publication IEICE TRANSACTIONS on ElectronicsVol.E79-CNo.5pp.617-622 Publication Date: 1996/05/25 Online ISSN: DOI: Print ISSN: 0916-8516 Type of Manuscript: Special Section PAPER (Special Issue on Microwave Devices for Mobile Communications) Category: Active Devices Keyword: AlGaAs/GaAs, power HBTs, digital cellular phones, optimal thermal design,
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Summary: AlGaAs/GaAs power HBTs for digital cellular phones have been developed. A three-dimensional thermal analysis taking the local-temperature dependence of the collector current into account was applied to the thermal design of the HBTs. The HBTs were fabricated using the hetero-guardring fully selfaligned transistor technique. The HBT with 220µm2 60 emitters produced a 31.7 dBm CW-output power and 46% poweradded efficiency with an adjacent channel leakage power of -49 dBc at the 50kHz offset bands for a 948 MHz π/4-shifted QPSK modulated signal at a low collector-emitter voltage of 3V. Through comparison with the conventional GaAs power FETs, it has been shown that AlGaAs/GaAs power HBTs have a great advantage in reducing the chip size.