On-Chip Temperature Compensation Active Bias Circuit Having Tunable Temperature Slope for GaAs FET MMIC PA

Shintaro SHINJO  Kazutomi MORI  Tomokazu OGOMI  Yoshihiro TSUKAHARA  Mitsuhiro SHIMOZAWA  

IEICE TRANSACTIONS on Electronics   Vol.E94-C    No.10    pp.1498-1507
Publication Date: 2011/10/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E94.C.1498
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technology)
Category: Active Devices and Circuits
temperature compensation,  MMIC power amplifiers,  GaAs FET,  threshold voltage,  

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An on-chip temperature compensation active bias circuit having tunable temperature slope has been proposed, and its application to an X-band GaAs FET monolithic microwave integrated circuit (MMIC) power amplifier (PA) is described. The proposed bias circuit can adjust the temperature slope of gate voltage according to the bias condition of the PA, and also realizes the higher temperature slope of the gate voltage by employing the diode and the FET which operates at near threshold voltage (Vt) in the bias circuit. As a result, the gain of PAs operated at any bias conditions is kept almost constant against temperature by applying the proposed bias circuit. Moreover, the proposed bias circuit can be integrated in the same chip with the MMIC PA since it does not need off-chip components, and operates with only negative voltage source. The fabricated results of the on-chip temperature compensation active bias circuit shows that the temperature slope of the gate voltage varies from 2.1 to 6.3 mV/, which is enough to compensate the gain of not only class-B PA but also class-A PA. The gain deviation of the developed GaAs FET MMIC PA with the proposed bias circuit has been reduced from 3.3 dB to 0.6 dB in the temperature range of 100.