Yukio Aoki

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This paper presents a highly compact 3 times 3 mm<sup>2</sup> WCDMA power amplifier (PA) module which integrates a GaAs HBT MMIC PA and a Si DC power management IC into one single package. A closed-loop controlled DC-DC buck converter allows the power management IC to adaptively optimize the PA collector voltage as a function of output power and thereby(More)
We have developed a compact dual-band (2.4/5 GHz) power-amplifier module with a concurrent two-stage InGaP/GaAs HBT for triple-mode (IEEE 802.11a/b/g) WLANs. The proposed diplexer-matching network is three-dimensionally implemented in an LTCC substrate (5/spl times/5 mm). The module exhibits an output power of 20 dBm at 2.4 GHz, and 18 dBm at 5.25 GHz with(More)
We have developed a wide-dynamic-range low-noise amplifier (LNA) based on InGaP/GaAs hetero bipolar transistors (HBTs) for 5-GHz-band wireless applications. With no external matching components, this dual-gain LNA (with a 20-dB gain attenuation function) has a very high performance; namely, a noise figure (NF) of 2.3 dB, a gain of 23 dB, an output 1-dB(More)
A packet-selective reconfigurable optical add/drop multiplexer (ROADM) that combines an acousto-optic wavelength-tunable filter (AOTF) and an optical packet ADM (PADM) using optical code label processing has been proposed and demonstrated. It provides more efficient utilization of wavelengths than conventional ROADMs. In this paper, we report an overview of(More)
VLSI yield optimization and design centering are two key interests in the development of submicron VLSI's. Accordingly, we have developed a new design automation technique based on simulation CAD tools. The features of this methodology are great reduction of simulation time in device optimization, and accurate prediction of process sensitivity in device(More)
We designed a continuously variable-gain low-noise-amplifier (VG-LNA) circuit with a noise figure (NF) of 1.4 dB. This VG-LNA has a diode-loaded emitter follower and a variable-current source. The diode-loaded emitter follower enables gain control without NF degradation at the maximum gain; the variable-current source improves the linearity and widens the(More)
This paper presents a dynamic predistorter (PD), which linearizes the dynamic AM-AM and AM-PM of a wideband code division multiple access handset power amplifier (PA). The dynamic PD allows an adjacent channel leakage power ratio (ACPR) improvement of 15.7 dB, which is superior to conventional PDs that linearize static AM-AM and AM-PM. The dynamic PD was(More)
This paper explains how the adjacent-channel-leakage-power ratio (ACLR) of power amplifiers (PAs) can be reduced by using gain-expansion amplifiers in tandem and generating anti-phase intermodulation distortion (IMD) in the driver stage to cancel the IMD in the output stage. The power-added-efficiency (PAE) can thus be increased by using near-class-B-biased(More)