J. Morikawa

NEC Corporation, Edo, Tōkyō, Japan

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Publications (7)6.13 Total impact

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    ABSTRACT: An L/S band high-power and low-distortion AlGaAs/GaAs heterostructure field-effect-transistor amplifier has been developed. The amplifier employed two pairs of prematched GaAs chips mounted on a single package, and the total output power was combined in a push-pull configuration with a low-loss microstrip balun circuit. The developed amplifier demonstrated state of-the-art performance of 140 W output power with 11.5 dB linear gain at 2.2 GHz. In addition, it exhibited extremely low distortion performance, which is suitable for digital cellular base station system applications
    IEEE Journal of Solid-State Circuits 10/1999; · 3.06 Impact Factor
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    ABSTRACT: An L/S-band high-power and low-distortion AlGaAs/GaAs HFET amplifier has been developed. The amplifier employed two pairs of pre-matched GaAs chips mounted on a single package and the total output-power was combined in push-pull configuration with a microstrip balun circuit. The developed amplifier demonstrated state-of-the-art performance of 140 W output-power with 11.5 dB linear gain at 2.2 GHz. In addition, it exhibited extremely low distortion performance, which is suitable for digital cellular base station system applications
    Gallium Arsenide Integrated Circuit (GaAs IC) Symposium, 1998. Technical Digest 1998., 20th Annual; 12/1998
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    ABSTRACT: We have developed a GaAs FET power amplifier that demonstrated a high power-added efficiency of 68% with 17.1 W output power and a 16 dB linear gain at 1.5 GHz. The developed 17 W amplifier also exhibited state of the art low distortion characteristics of less than -21 dBc NPR (Noise Power Ratio) at the 5 dB-output power back-off point from 2 dB-gain compression point. These excellent results are performed by optimizing the drain bias circuit as well as the internal matching network
    Microwave Symposium Digest, 1998 IEEE MTT-S International; 07/1998
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    ABSTRACT: A 50-W low distortion GaAs MESFET for L-band has been successfully developed by optimizing chip design and adopting nearly class-B push-pull operation. The newly developed FET achieved a P<sub>1 dB</sub> of 47.1 dBm (51.3 W) with a linear gain (GL) of 13.1 dB and the maximum drain efficiency of 57% (f=1.5 GHz, V<sub>DS</sub>=10 V, I<sub>DS</sub>=3%I<sub>dss</sub>). A saturation output power of 47.3 dBm (53.7 W) has also been obtained. This is the highest output power reported so far of GaAs FETs considering an operation at nearly class B. In addition, the FETs exhibited both good linearity and distortion performances. The newly developed FETs will contribute to the improvement in performance of digital cellular base station systems
    IEEE Journal of Solid-State Circuits 10/1997; · 3.06 Impact Factor
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    ABSTRACT: An S-band high-efficiency power GaAs MESFET has been developed by employing the second-harmonic terminating technique in both the input and output matching circuits. This internally matched power FET demonstrates state-of-the-art performance of 30.9 W (44.9 dBm) output power with more than 60% power-added efficiency and a 15.0 dB linear gain at 2.5 GHz. Successful termination of the second-harmonic was confirmed by measuring gate and drain voltage waveforms using EOS (Electro-Optic Sampling). This amplifier can be assembled in conventional ceramic package, and thus is suitable for satellite communication system applications
    Microwave Symposium Digest, 1997., IEEE MTT-S International; 07/1997
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    ABSTRACT: This paper describes DC and RF power performance of a newly-developed high-power AlGaAs/GaAs heterostructure FET (HFET) designed for L-band SSPA applications. A push-pull power amplifier, composed of two HFET chips, demonstrated state-of-the-art power performance of 60 W output-power with a power-added efficiency (PAE) of 54% at 1.5 GHz
    Microwave Symposium Digest, 1997., IEEE MTT-S International; 07/1997
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    ABSTRACT: A 50 W low distortion GaAs MESFET for L-band has been successfully developed by optimizing chip design and adopting nearly B-class push-pull operation. The newly developed FET achieved a P<sub>1 dB</sub> of 47.1 dBm (51.3 W) with a linear gain (GL) of 13.1 dB and the maximum drain efficiency of 57% (at freq=1.5 GHz, V<sub>DS</sub>=10 V, set I<sub>DS</sub>=3%Idss). A saturation output power of 47.3 dBm (53.7 W) has also been obtained. This is the highest output power reported so far of GaAs FETs considering an operation at nearly class B. In addition, the FETs exhibited both good linearity and distortion performances. The newly developed FETs will contribute to the improvement in performance of digital cellular base station systems
    Gallium Arsenide Integrated Circuit (GaAs IC) Symposium, 1996. Technical Digest 1996., 18th Annual; 12/1996