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Design of a High-Efficiency and High-Power Inverted Doherty Amplifier
Gunhyun Ahn,Min-su Kim,Hyun-chul Park,Sung-chan Jung,Ju-ho Van,Hanjin Cho,Sung-wook Kwon,Jong-hyuk Jeong,Kyung-hoon Lim,Jae Young Kim,Sung Chan Song,Cheon-seok Park,Youngoo Yang IEEE 2007 IEEE transactions on microwave theory and techniqu Vol.55 No.6
<P>In this paper, we present a design method for a compact inverted Doherty power amplifier (IDPA), which has high-efficiency and high-power characteristics. An optimum load matching network and an additional offset line, after the matching network of the carrier amplifier, dynamically modulate the load impedance according to the input power drive, while the conventional Doherty power amplifier uses a quarter-wave line to do it. The operational principles and design guide are provided. For experimental verification, a 50-W Doherty amplifier was designed for the pi/4 differential quadrature phase-shift keying application at the 860-MHz band. The measured performance of the IDPA was compared with that of the balanced class-AB amplifier with the same output matching network. At an output power of 50 W, the IDPA performs with 3.16 dB better adjacent channel power ratio (-28 versus -24.84 dBc) and 6.15% higher power-added efficiency (59.02 versus 52.87%) than the class-AB amplifier does.</P>
A 60-W Multicarrier WCDMA Power Amplifier Using an RF Predistorter
Kyung-Hoon Lim,Gunhyun Ahn,Sungchan Jung,Hyun-Chul Park,Min-Su Kim,Ju-Ho Van,Hanjin Cho,Jong-Hyuk Jeong,Cheon-Seok Park,Youngoo Yang IEEE 2009 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS PART 2 E Vol.56 No.4
<P>In this brief, we present a 60-W power amplifier that is linearized using an RF predistorter for multicarrier wideband code-division multiple-access (WCDMA) applications. The proposed RF predistorter is fully composed of RF or analog circuits, and it has a moderate memory effect compensation capability using a delayed third-order intermodulation (IM3) component path. It also includes the IM5 generation circuits and a compact IM3 generator that is capable of autocanceling for the fundamental component. The proposed RF predistorter was implemented and applied to a 60-W high-power WCDMA amplifier. For a four-carrier downlink WCDMA signal, the RF predistorter improved the adjacent channel leakage power ratio at a 5-MHz offset by 6.19 dB at an average output power of 48 dBm. The total efficiency of the system is as high as 13.6% at the same output power level. At an output power level of 60 W, the linearized power amplifier complies with the linearity specification of the WCDMA system.</P>
배전계통의 순간전압 상승에 따른 SPD 고압 TOV 시험설비 구축
김용성(Young-Sung Kim),김언석(Oun-Seok,Kim),안건현(Gunhyun Ahn) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
본 논문에서는 저압 서지보호기의 안전성평가를 위한 고압계통 고장에 의한 순간 과전압시험 설비를 IEC 61643-1의 따라 구축 하였고, 구축된 시험설비의 성능을 분석하였다. 고압 계통의 순간 과전압 시험 기준은 가장 일반적인 미국전력 계통의 기준인 3상 4선식이 반영이 되었으며 전압의 크기는 AC 1200V이다. 본 논문에서는 순간과전압이 상과 접지사이의 개방전압 AC 1200V을 약 200ms 동안 인가되는지를 측정하였고, 단락전류가 AC 300A이상을 측정하였다.
A high-frequency and high-power quasi-class-E amplifier design using a finite bias feed inductor
Van, Ju-Ho,Kim, Min-Su,Jung, Sung-Chan,Park, Hyun-Chul,Ahn, Gunhyun,Park, Cheon-Seok,Kim, Byung-Sung,Yang, Youngoo Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.49 No.5
<P>This paper presents a design method for a compact high-efficiency quasi-class-E amplifier, using a finite bias feed inductor. It is very difficult to achieve proper class-E operation from high-power transistors operating in the high-frequency region because of their internal parasitic components. To mitigate the effects of internal parasitic components on class-E operation, a finite DC feed inductance is introduced to resonate out the capacitive parasitic components. A quasi-class-E amplifier with a finite DC feed inductor was designed and implemented at 1.2 GHz using a high-power laterally diffused metal-oxide-semiconductor field-effect transistor (LDMOSFET). We compared simulated time domain current and voltage waveforms with ideal ones. As the test results indicated, power-added efficiency as high as 70.4% was achieved, at high output power of 39.55 dBm, without losing the circuits' simplicity, one of the most important advantages of class-E operation. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1114–1118, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22368</P>