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IMT-2000 기지국용 도허티 전력증폭기의 설계 및 선형성과 효율 분석
김선근,김기문,Kim Seon-Keun,Kim Ki-Moon 한국정보통신학회 2005 한국정보통신학회논문지 Vol.9 No.2
본 논문에서는 여러 가지 효율 개선 방법 중에서 Doherty Amplifier에 관해 논하였다. 간단한 회로를 이용하여 하나의 PEP 180w급 LDMOS를 사용하여 효율성과 선형성 개선에 관한 성능분석을 하였다 제작된 Doherty Amp의 성능을 검증하기 위해 Balanced Class AB Amplifier와 성능을 비교하였다. 실험결과 peaking Amp의 $V_gs.P$가 1.53V일 때 효율이 최대 11.6$\%$ 이상 증가되었으며 매뉴얼로 gate bias 조절을 통하여 선형성 개선의 최적 bias point를 찾은 후 WCDMA 4fA에서는 $V_gs.P$가 3.68V일 때 IMSR (InterModulation to Signal Ratio)이 최대 3.34dB가 증가됨을 보였다. 특히 1.53V로 peaking amp의 bias point를 맞추게 되면 출력 전력 434Bm에서 -324Bc 이하의 IMSR과 탁월한 효율 증가를 얻을 수 있었다. During several method of improvement efficient, We analyzed Doherty Amplifier That used by simple circuit and 180w PEP LDMOS to analyze improvement of efficient and linearity. We for testing performance of Doherty Amplifier compared with Balanced Class AB, the experimental results show when Peaking Amp $V_gs.P$=1.53V, the efficiency is increased at Maximum 11.6$\%$. After finding optimum bias point of linearity improvement by manual tuning gate bias, when WCDMA 4FA $V_gs.P$=3.68V IMSR could be increased maximum 3.34dB. especially, when we match bias point of Peaking amp at 1.53V, we could get a excellent efficiency increase and have fUR under -3203c at output power 43dBm.
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Feedforward 선형 전력증폭기를 위한 에러증폭기의 구현 및 성능평가에 관한 연구
전중성(Joong-Sung Jeon),조희제(Hee-Jea Cho),김선근(Seon-Keun Kim),김기문(Ki-Moon Kim) 한국항해항만학회 2003 한국항해항만학회지 Vol.27 No.2
본 논문은 IMT-2000 기지국용 15 Watt Feedforward 선형전력증폭기(Linear Power Amplifier; LPA)의 구현을 위한 에러증폭기를 설계 및 제작하여, 그 성능을 평가하였다. 에러증폭기는 상호 변조 왜곡 신호(Intermodulation Distortion IMD)만을 검출하기 위한 빼기회로, RF 신호의 세기 및 위상을 제어하기 위한 가변 감쇠기, 가변 위상변환기, 그리고 신호의 증폭을 위한 저전력증폭기, 대전력증폭기로 구성되었다. 이들 구성요소는 RO4350 기판 위에 구현되어, 틴 도금한 알루미늄 기구를 안에 바이어스 회로와 함께 집적하였다. 제작시 RF 회로부의 바이어스 회로에 전원을 공급하기 위하여 내벽에 관통형 커패시터를 삽입하여 DC 전원에 의한 스퓨리어스 성분이 제거되도록 하였다. 제작된 에러증폭기는 45㏈ 이상의 이득, ± 0.66㏈의 이득평탄도, -15㏈ 이하의 입력반사 손실 특성을 나타내었다. 또한 성능을 평가하기 위해 Feedforward 방식의 LPA에 적용한 결과 주증폭기의 IM3 성분이 34㏈c에서 61㏈c, 개선되었다. 이때 오차루프의 상쇄지수는 약 27㏈, 최종 출력 전력은 15 W로 나타났다. In this paper, We tested and fabricated the error amplifier for the 15 Watt linear power amplifier for the IMT-2000 baseband station. The error amplifier was comprised of subtractor for detecting intermodulation distortion, variable attenuator for control amplitude, variable phase shifter for control phase, low power amplifier and high power amplifier. This component was designed on the RO4350 substrate and integrated the aluminum case with active biasing circuit. For suppression of spurious, the through capacitance was used. The characteristics of error amplifier measured up to 45㏈ gain, ± 0.66㏈ gain flatness and -15㏈ input return loss. Results of application to the 15 Watt feedforward Linear Power Amplifier, the error amplifier improved with 27㏈ cancellation from 34㏈c to 61㏈c IM₃.
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Feedforward 선형화 방식을 위한 에러증폭기의 구현 및 성능평가에 관한 연구
전중성(Joong Sung Jeon),조희제(Hee Jea Cho),양승국(Sung Kuk Yang),이영섭(Young Sub Lee),김선근(Seon Keun Kim),김기문(Ki Moon Kim) 한국마린엔지니어링학회 2003 한국마린엔지니어링학회 학술대회 논문집 Vol.2003 No.-
In this paper, We tested and fabricated the correction amplifier for the 30 Watt linear power amplifier in frequency band 2.11 - 2.17 GHz. The correction Amplifier was comprised of subtractor, variable attenuator, variable phase shifter and power amplifier. This component was designed on the R04350 substrate and integrated the aluminum case with active biasing circuit. For suppression of spurious, the through capacitance was used. The characteristics of correction amplifier measured up to 45 dB gain, ±0.66 dB gain flatness and -15 dB input return loss. Results of application to the feed forward LP A, the correction amplifier improved with 27 dB cancel to the IMD.
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金善根 세종대학교 1981 세종대학 논문집 Vol.8 No.-
The purpose of this paper is to suggest a few directions to improve our technology import policy for the economic development after discussing the nature of technology transfer and surveying our status and policy of technology imports. The total number of technology imports approved by the authorities concerned in Korea from 1962 to 1979 was 1467, for which Koreans paid about $350,598,000. The subjects of technology imported untill 1975 in Korea was mainly Know-hows and trademarks whose royalty was relatively low. But from 1976, the importation of patented technology has gardually been increased. Due to the lack of informations about an advanced technology and to the shortage of an evaluation capacity, however, an updated technology was difficult to be introduced in Korea. Because of the poor ability and capacity to absorb an advanced technology, about 67.6% of firms that imported foreign technology have digested, applied in practice and developed the technology ofter adjusting in to thier own needs. Our palicy was intially to regulate an unselective import of technology. As of 1980, however, about 90% of technology imports are approved by the authorities concerned automatically. To improve the efficiency of technology imports for our economic development, we need thoroughly to understand the subjects and nature of applieable technology and the conditions and channels of technology tranfer in the international technology markets. In addition, we need to cultivate an ability to understand an important technology whose effects are highly related in various firms or industries for a productivity increase, and a sufficient level of technical capacity conductive to more improved and advanced technology is also essential for an effective importation of technology to assure our continuous economic growth.
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Aerosol Reactor를 이용한 고분자 입자의 제조
김성익,김선근 중앙대학교 생산공학연구소 1992 생산공학연구소 논문집 Vol.1 No.1
Spherical polymer particles with narrow size distribution have been prepared by aerosol-phase polymerization. The aerosol-phase reactor has advantages over the conventional methods in the preparation of spherical, monodisperse particles with controllable size. The aerosol reaction system consisted of seed generator, boiler, condenser, reboiler, recondenser, reactor and particle collector in series. The polyurea particles were prepared by the reaction of TDI(toluene-2,4-diisocyanate) or HDI(hexamethylenediisocyanate) droplets with EDA(ethylenediamine) vapor. The use of seed(NaCl) nuclei helped the polymer particles smaller in size and made the size distribution of the particles narrower. The particle size increased substantially with boiler temperature and decrease slightly with increasing the carrier gas flow rate. Increase in reboiler temperature improved the monodispersity of the particle size. Sphericity and surface smoothness of the particles were improved by decreasing particle size and controlling the reaction rates. The coating of TiO₂on the surface of the preapared polymer paticles was carried out by condensing Ti(Oet)₄on the particle surface and subsequently reacting the liquid film with water vapor. The reaction system was also applied to prepare polyamide particles successfully.
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