Jin-Ho Shin

Pohang University of Science and Technology, Geijitsu, Gyeongsangbuk-do, South Korea

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Publications (6)2.75 Total impact

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    ABSTRACT: Fully integrated Doherty amplifiers have been developed for 5 GHz wireless-LAN (WLAN) applications. Through a new Doherty power amplifier circuit topology, the bulky Doherty in/output matching block including quarter-wave (lambda/4) impedance transformer can be fully integrated using capacitors, short micro-strip lines and bonding wires. To improve efficiency at a full power, without using the bulky input power splitter, a new input power driving concept is implemented by inserting lambda/4 impedance transformers at the inputs of the carrier and peaking amplifiers using the lumped elements. The amplifier based on InGaP HBT technology, shows an output power of 22.5 dBm and a power-added efficiency (PAE) of 21.3 % at an error vector magnitude (EVM) of 5%, measured with 54 Mbps 64-QAM-OFDM signals at 5.2 GHz. The proposed in/output matching topology allows the fully integrated Doherty amplifiers with a small size
    Preview · Conference Paper · Jul 2006
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    ABSTRACT: Based on an analog-gain control bias circuit (AGBC), a dynamic and fixed bias-controlled InGaP/GaAs HBT MMIC power amplifier module (PAM) is designed for code-division multiple-access (CDMA) and advanced mobile-phone service (AMPS) handset applications. The proposed AGBC effectively improves the power-added efficiency (PAE) of a power amplifier (PA) over a wide range of output power while satisfying the CDMA/AMPS linearity requirements. The PA gain slope with respect to AGBC mode-control voltage is about 12 dB/V. The measured average current of this AGBC PA is reduced by 64% compared to a standard PA. The AGBC PA exhibits a 28 dB power gain, a 45% PAE, and a -49 dBc adjacent channel power ratio (ACPR) at 28 dBm output power with a fixed mode-control voltage.
    No preview · Conference Paper · Jul 2004
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    ABSTRACT: We have investigated the surface recombination and its 1/f noise properties of AlGaAs/GaAs HBT's as a function of the emitter-base structure and the surface passivation condition. It is found that the surface recombination 1/f noise can be significantly reduced by the heterojunction launcher of the abrupt junction with 30% Al mole fraction emitter. The depleted AlGaAs ledge surface passivation further suppresses the surface recombination currents. Consequently, we have achieved a very low 1/f noise corner frequency of 2.8 kHz at the collector current density of 10 kA/cm<sup>2</sup>. The dominant noise source of the HBT is not a surface recombination current, but a bulk current noise. This is the lowest 1/f noise corner frequency among the III-V compound semiconductor devices, and comparable to those of low-noise Si BJTs
    No preview · Conference Paper · Jul 1997
  • Jin-Ho Shin · Yujin Chung · Youngseok Suh · Bumman Kim
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    ABSTRACT: The first quantitative extraction of low-frequency noise equivalent circuit model of self-aligned AlGaAs/GaAs heterojunction bipolar transistor has been performed. It is based on a generalized small signal circuit model including the base and emitter series resistance noise sources. The dominant noise sources are emitter-base current noise source and the resistance noise source. The emitter-collector current noise source is negligible
    No preview · Conference Paper · Jul 1996
  • Source
    Jin-Ho Shin · Joonwoo Lee · Youngseok Suh · Bumman Kim
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    ABSTRACT: To reduce the low-frequency noise, HBTs with a large emitter size of 120/spl times/120 /spl mu/m/sup 2/ are fabricated on abrupt emitter-base junction materials without undoped spacer. The HBTs exhibit an internal noise corner frequency of 100 Hz, which is much lower than about 100 kHz of conventional AlGaAs/GaAs HBTs. From the very low noise HBTs, the existence of resistance fluctuation 1/f noise is clearly verified by the simple comparison of collector current noise spectra with different base terminations. It is found that, at a high emitter-base forward bias, the resistance fluctuation 1/f noise becomes dominant for shorted base-emitter termination, but the internal 1/f noise dominant for open base. Device design rules for low noise small-feature size HBT, including resistance fluctuation, are discussed.
    Preview · Article · Mar 1996 · IEEE Electron Device Letters
  • Source
    Joongjin Nam · Jin-Ho Shin · Bumman Kim
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    ABSTRACT: A MMIC PA with continuous bias Control circuit for cellular handsets has been implemented. It has been shown that power amplifier with continuous bias control circuit can increase the standby and talk time by lowering the average current consumption. The average current of the continuous bias control is 37.9mA in urban and 59.2mA in suburban CDMA environment, which is reduced by 45.9% and 60.6%,respectively compared to normal operation (no bias control). The ACPR is below 47.3dBc, and the PAE is about 42.3% in both operations.
    Preview · Article ·

Publication Stats

45 Citations
2.75 Total Impact Points


  • 1996-1997
    • Pohang University of Science and Technology
      • Department of Electronic and Electrical Engineering
      Geijitsu, Gyeongsangbuk-do, South Korea