Keiichi Yamaguchi

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A reactance-compensation technique has been introduced recently for the design of wideband class-E power amplifiers (PAs). With this technique, the load resistance can be transformed to an optimal complex drain impedance in a broad frequency band. One potential problem of this technique is that an additional network is often needed to transform 50 Ω(More)
Design and experimental results of a wideband and highly efficient class-E power amplifier are reported in this paper. The amplifier can cover the whole UHF broadcast band from 470MHz to 860MHz with an output power of 10W. The PA can achieve better than 70% power added efficiency (PAE) in a fractional bandwidth of 41% or better than 60% PAE in a bandwidth(More)
This paper describes single 2.2 V operation of a two-stage MMIC power amplifier for 2.4 GHz wireless local area network applications. The MMIC with 0.76/spl times/ 0.96 mm/sup 2/ area is composed of n-AlGaAs/InGaAs/n-AlGaAs FETs with a shallow threshold voltage of -0.24 V and SrTiO/sub 3/ capacitors. The capacitors with a high relative dielectric constant(More)
This paper describes 950 MHz power performance of a 7.0 mm gate width double-doped AlGaAs-InGaAs-AlGaAs heterojunction FET (HJFET) with a 0.8 /spl mu/m long WSi gate for personal digital cellular phones. The fabricated HJFET exhibited 2.3 /spl Omega/.mm on-resistance, 600 mA/mm maximum drain current, 330 mS/mm transconductance and 12.7 V gate-to-drain(More)
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