Small-Cell 2.6 GHz Doherty 표 1. Silicon LDMOS FET Table 1. Comparison of silicon LDMOS FET and GaN- HEMT. Silicon LDMOS FET Bandgap 1.1 ev 3.4 ev 75 V

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1 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE Feb.; 27(2), ISSN (Print) ISSN X (Online) Small-Cell 2.6 GHz Doherty Design of a 2.6 GHz Doherty Power Amplifier IC for Small-Cell Base Station Systems 이휘섭 임원섭 강현욱 이우석 이형준 윤정상 이동우 양영구 Hwiseob Lee Wonseob Lim Hyunuk Kang Wooseok Lee Hyoungjun Lee* Jeongsang Yoon* Dongwoo Lee* Youngoo Yang 요약 2.6 GHz Doherty. Small-cell, Doherty QFN. Doherty 10 MHz 6.5 db PAPR 2.6 GHz LTE 33.9 dbm 15.8 db, 43.0% 30.0 dbc ACLR. Abstract This paper presents a 2.6 GHz Doherty power amplifier IC to enhance the back-off efficiency. In order to apply to small-cell base stations, the Doherty power amplifier was fabricated using process for high power density. In addition, the implemented Doherty power amplifier was mounted on a QFN package. The implemented Doherty power amplifier was measured using LTE downlink signal with 10 MHz bandwidth and 6.5 db PAPR for verification. A power gain of 15.8 db, a drain efficiency of 43.0 %, and an ACLR of 30.0 dbc were obtained at an average output power level of 33.9 dbm. Key words:, Doherty Power Amplifier, Small-Cell Base Station, LTE. 서론 LTE(Long Term Evolution) pico-cell femto-cell small-cell. small-cell 2 W,. (Gallium Nitride High Electron Mobility Transistor). [1] [6]. 1 This work was supported by the Technology Innovation Program( ) funded by the Ministry of Trade, Industry & Energy(MI, Korea). (School of Information and Communication Engineering, Sungkyunkwan University) *( ) (Wave Electronics Co., Ltd.) Manuscript received September 24, 2015 ; Revised January 11, 2016 ; Accepted January 11, (ID No S) Corresponding Author: Youngoo Yang ( yang09@skku.edu) 108 c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.

2 Small-Cell 2.6 GHz Doherty 표 1. Silicon LDMOS FET Table 1. Comparison of silicon LDMOS FET and GaN- HEMT. Silicon LDMOS FET Bandgap 1.1 ev 3.4 ev 75 V 175 V 1 W/mm 4 ~ 8 W/mm 3.8 GHz > 12 GHz silicon LDMOS(Laterally Diffused Metal Oxide Semiconductor) FET(field effect transistor). PAPR (Peak-To-Average Power Ratio).. Doherty., [7] [12]. 2.6 GHz Doherty. QFN. Doherty LTE,.. 설계및시뮬레이션 1 Doherty. carrier peaking. cell, gate length 720 μm. Cemax CMX25Q03 90, RN2 그림 1. Doherty Fig. 1. Overall schematic diagram of the Doherty power amplifier. 그림 2. Fig. 2. Input matching network. RDO2650Q03 Doherty. bond-wire Keysight ADS (Advanced Design System) Momentum tool EM. 2 Doherty. 50 source (Z S ). EM 33 db 1.1 db. bond-wire lead. QFN EM 3(a). bonding pad lead 1 mil bond-wire 2 pad. 109

3 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 2, Feb (a) EM 3D (a) 3D view of the package for EM simulation 3(b) bond-wire inductance resistance. 2.6 GHz 1.28 mm 0.89 nh inductance 0.13 resistance, 1.08 mm 0.78 nh inductance 0.11 resistance. 4 Doherty dbm 6.5 db back-off 33.9 dbm 16.1 db 50.1%.. 제작및측정결과 (b) Bond-wire (b) Simulated results of the bond-wires 그림 3. QFN EM Fig. 3. EM simulation for the QFN package. 그림 4. Doherty Fig. 4. Simulated performances of the designed Doherty power amplifier. Doherty 5. 5(a), Doherty Cree 0.4-μm, mm mm 2 QFN. 5(b) Doherty evaluation module, module mm 2. evaluation module 0.5 mm Rogers RO4350B PCB(Printed Circuit Board), PCB. Doherty MHz 6.5 db PAPR 2.6 GHz LTE downlink, 48 V. Carrier 11 ma Class-AB, peaking 4.6 V Class-C. 6(a), ACLR(Adjecent Channel Leakage Ratio) 6(b) dbm %, ACLR 30.0 dbc. GaN- HEMT Doherty 110

4 Small-Cell 2.6 GHz Doherty (a) QFN Doherty (a) A photograph of the fabricated Doherty power amplifier IC mounted in QFN package (a) (a) Power gain and drain efficiency (b) (b) ACLR 그림 6. LTE Fig. 6. Measured performances for the LTE modulation signal. (b) Evaluation module (b) A photograph of the evaluation module 그림 5. Doherty Fig. 5. Implemented Doherty power amplifier. 2.. 결론 0.4-μm Doherty. bond-wire lead EM. small-cell QFN Doherty. Doherty. 10 MHz 6.5 db PAPR 2.6 GHz LTE downlink, 111

5 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 2, Feb 표 2. Doherty Table 2. Performance comparison to the previously published Doherty power amplifier ICs. Reference Frequency [GHz] [1] 2.60 [2] 2.14 [6] 2.65 [11] 2.14 This work 2.60 Device technology 0.40-μm P OUT [dbm] DE [%] ACLR [dbc] Size [mm 2 ] Package Modulation signal N/A COB LTE COB WCDMA COB LTE COB LTE QFN LTE DE: drain efficiency, COB: chip on board, *w/o linearization dbm 15.8 db, 43.0% 30.0 dbc ACLR. References [1] S. Jee, J. Lee, B. Park, C. Kim, and B. Kim, "GaN MMIC broadband Doherty power amplifier", in Asia- Pasific Microw. Conf. Dig., pp , Nov [2] J. Lee, D. Lee, and S. Hong, "A Doherty power amplifier with a GaN MMIC for femtocell base stations", IEEE Microw. Wireless Compon. Lett., vol. 24, no. 3, pp , Mar [3],,,,, "2.6 GHz ",, 2(1), p. 63, [4] J. Komiak, "GaN HEMT: Dominant force in high-frequency solid-stage power amplifiers", IEEE Microw. Mag., vol. 16, pp , Apr [5] Y. Park, J. Lee, S. Jee, S. Kim, C. Kim. B. Park, and B. Kim, "GaN HEMT MMIC Doherty power amplifier with high gain and high PAE", IEEE Microw. Wireless Compon. Lett., vol. 25, no. 3, pp , Mar [6] S. Jee, Y. Park, Y. Cho, J. Lee, S. Kim, and B. Kim, "A highly linear dual-band Doherty power amplifier for femto-cell base stations", in IEEE MTT-S Int. Microw. Symp. Dig., pp. 1-4, May [7] Y. Yang, J. Cha, B. Shin, and B. Kim, "A fully matched N-way Doherty amplifier with optimized linearity", IE- EE Trans. Microw. Theory Tech., vol. 51, no. 3, pp , Mar [8] D. Kang, J. Choi, D. Kim, and B. Kim, "Design of Doherty power amplifiers for handset applications", IEEE Trans. Microw. Theory Tech., vol. 58, no. 8, pp , Aug [9] J. Park, D. Kim, C. Yoo, W. Lee, J. Yook, S. Chun, J. Kim, and C. Hahn, "GaN HEMT based high power and high efficiency Doherty amplifiers with digital pre-distortion correction for WiBro applications", J. Korean Inst. Electromagn. Eng. Sci., vol. 11, no. 1, pp , Mar [10],,,,,, "GaN HEMT ",, 35(1), pp , [11] S. Jee, J. Lee, S. Kem, Y. Park, and B. Kim, "Highly linear 2-stage Doherty power amplifier using GaN MM- 112

6 Small-Cell 2.6 GHz Doherty IC", J. Electronagn. Eng. Sci., vol. 14, no. 4, pp , Dec [12] V. Camarchia, M. Pirola, R. Quaglia, S. Jee, Y. Cho, and B. Kim, "The Doherty power amplifier: review of recent solutions and trends", IEEE Trans. Microw. Theory Tech., vol. 63, no. 2, pp , Feb : ( ) : ( ) : Amplifier IC, Broadband Power Amplifier and Passive Circuit, Wireless Power Transfer : ( ) : Amplifier, Broadband Power Amplifier and Passive Circuit : ( ) : Amplifier IC, Analog/Mixed-Signal IC, High-Speed DC-DC Converter : : [ 주관심분야 ], : ( ) : Amplifier, Broadband and Linearization Techniques : ( ) : ( ) : : [ 주관심분야 ], 113

7 THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 2, Feb : ( ) : ( ) : : : [ 주관심분야 ], : ( ) : ( ) : : Skyworks Solutions Inc. Senior Electronic Engineer : [ 주관심분야 ], /, 114