Shoichi Hara

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This paper proposes a multiple-divide technique using by-2, by-3, and by-4 frequency dividers to realize a lower phase-noise LC-VCO, and explores the design space of low-phasenoise VCO using the multiple-divide technique. In the simulated results using 90-nm CMOS model parameters, the optimum frequency range, achieving better than −191 dBc/Hz of FoM, can be(More)
The multiple-divide technique, using the multi-ratio frequency divider, has a possibility to improve FoM of VCO. This paper proposes a design optimization of LC-VCO using the multiple-divide technique. In the simulated results using 90-nm CMOS model parameters, the optimum frequency range, achieving better than −187.0 dBc/Hz of FoM, can be extended from(More)
This paper presents a LC-based sub-harmonic injection-locked frequency quadrupler which multiplies a 15 GHz input to 60 GHz quadrature(I/Q) output signals. The proposed quadrupler can use a lower-frequency PLL for incident signal than doublers and triplers, which is very advantageous to implement a wide-tuning and low-phase-noise PLL. The proposed frequency(More)
There is a large difference between the waveforms of high speed digital signals measured on a printed circuit board and those at the receiving terminals of LSI chips. In order to ensure that the high speed digital signal is correctly transferred, one of the major issues is how to estimate the waveform at the receiving terminal, where the waveform cannot be(More)
In this paper we present a study on the design optimization of voltage-controlled oscillators. The phase noise of LC-type oscillators is basically limited by the quality factor of inductors. It has been experimentally shown that higher-Q inductors can be achieved at higher frequencies while the oscillation frequency is limited by parasitic capacitances. In(More)
A novel linearization technique which improves the phase distortion and gain compression of a power amplifier is proposed in this paper. Moreover, a low distortion and high efficiency AlGaAs/GaAs HBT MMIC power amplifier for the 1.9 GHz PHS system has been demonstrated using the novel linearization technique. The HBT MMIC power amplifier exhibits an output(More)
The multiple-divide technique, using the multiratio frequency divider, has a possibility to improve FoM of VCO. This paper proposes a design optimization of LC-VCO using the multiple-divide technique. In the simulated results using 90-nm CMOS model parameters, the optimum frequency range, achieving better than −187.0 dBc/Hz of FoM, can be extended from(More)
This paper proposes a novel wideband voltage-controlled oscillator (VCO) for multi-band transceivers. The proposed oscillator has a core VCO and a tuning-range extension circuit, which consists of an injection-locked frequency divider (ILFD) and flip flop dividers. The two-stage differential ILFD generates quadrature outputs and realizes two, three, four,(More)
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