THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. 2016 Jul.; 27(7), 625634. http://dx.doi.org/10.5515/kjkiees.2016.27.7.625 ISSN 1226-3133 (Print)ISSN 2288-226X (Online) Near-Field Receiving Measurement of Active Phased Array Antenna for Full Digital Radar Application 채희덕 이재민 김영완 김한생 진형석 박종국 Heeduck ChaeJae-Min LeeYoung-Wan KimHanSaeng KimHyoung Seog JinJongkuk Park 요약..,, (G/T), L-. Abstract A full digital receiving active phased array antenna generates final receiving beams by digital beam forming of received digital signals in element-level that makes difficult to use typical near-field measurement method. Thus in this paper, a modified near-field measurement method which is suitable for full digital receiving active phased array antenna is proposed. Also the measured results of receiving beam pattern and G/T using developed L-band full digital receiving active phased array antenna are shown for the verification of proposed method. Key words: Active Phased Array Antenna, Near-Field Measurement, Digital Radar, Digital Beam Forming, Full Digital. 서론 [1],[2].,. I/Q.,, (full digital radar) LIG(LIGNex1) Manuscript received April 18, 2016 ; Revised June 13, 2016 ; Accepted June 30, 2016. (ID No. 20160418-044) Corresponding Author: Heeduck Chae (e-mail: heeduck.chae@lignex1.com) c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved. 625
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 7, Jul. 2016. [2]. RF [3][5]., RF., (G/T) [5],[6]..,,,., G/T,.,,,.. 완전디지털수신능동위상배열안테나개요 2-1 완전디지털수신능동위상배열안테나구성 L- 1 42, /. (SSPA: Solid State Power Amplifier)(LNA: Low Noi- 그림 1. Fig. 1. Block diagram of active phased array antenna using full digital receiving. se Amplifier), ADC (Analog to Digital Converter) DDC(Digital Down Converter).,.. SSPA. / /, ADC/DDC I/Q,. /.,.., 626
. 2-2 수신빔형성,. (1)...,.,,. (3),. (3) (1) (2). (2) (4)..., ( ) ( ).,. 2-3 잡음형성및 G/T G/T.. G/T. (2)..,,. (7) (5) (6) 627
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 7, Jul. 2016.. (3)(5). (8) ( ) ( ). (5) (8). (9).. (9) (10) Boltzmann,. (9) G/N (10) G/T.. 완전디지털수신능동위상배열안테나근접전계수신시험 3-1 근접전계시험구성 L 12 m 12 m. 2. 그림 2. Fig. 2. Near-field Rx measurement setup., network analyzer... RF I/Q DC RF LO, DDC.... 628
I/Q I/Q,, I/Q. [7],[8].,. 3-2 근접전계시험순서, G/T. 3,, G/T. /.,.., / 그림 3. Fig. 3. Rx measurement procedure of active phased array antenna using digital receiving..,. 3-3 수신빔측정결과. 4(a).,. 4(b).,. / 5. 0.026 db 0.35. 629
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 7, Jul. 2016. (a) (b) 그림 4. (a) (b) Fig. 4. Vertical pattern magnitude and phase of radiating element. (a) before and (b) after alignment. (a) (a) Magnitude (a) 그림 5. (a) (b) Fig. 5. Difference of calibration data before and after nearfield pattern measurement. (a) magnitude, (b) phase.., [9] 6., (b) (b) (b) Phase 그림 6. Fig. 6. Near-field data back-projected on the aperture after digital beam forming.. 7.,. 630
3-4 잡음측정결과및 G/T (G/N),.. (a) (a) Azimuth (a) (a) Each channel (b) (b) Elevation 그림 7. Fig. 7. Monopulse beam pattern after digital beam forming. / 35 db. 81.62 db. 그림 8. Fig. 8. Power of noise signal. (b) (b) After digital beam forming 631
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 7, Jul. 2016. 표 1. G/N Table 1. Comparison between G/N estimation and experimental results. G/N() () () () () () 81.62 db 61.27 dbm 142.89 dbi/dbm 36.32 dbi 0.78 db 2.87 db 2.5 MHz () 291 K G/N() 142.65 dbi/dbm 8(a). 8(b). 61.27 dbm. (9) G/N 142.89 dbi/dbm. 2.5 MHz (10) G/T 8.27 db/k.,,, G/N G/N 1. G/N 0.24 db. G/T G/N. G/T G/N.. 결론, L., G/T G/N,.,. References [1],,, " ",, 25(2), pp. 39-49, 2014 3. [2] S. H. Talisa, K. W. O haver, T. M. Comberiate, M. D. Sharp, and O. F. Somerlock, "Benefits of digital phased array radars", Proceedings of the IEEE, vol. 104, no. 3, pp. 530-543, Mar. 2016. [3] W. Haselwander, M. Uhlmann, S. Wustefeld, and M. Bock, "Measurement on an active phased array antenna on a near-field range and an anechoic far-field chamber", 31st European Microwave Conference, London, Sep. 2001. [4],,,,, " ",, 22(12), pp. 1155-1163, 2011 12. [5],,,,, " ",, 25(2), pp. 50-59, 2014 3. [6] D. M. Pozar, Microwave Engineering, 3rd Ed., John Wiley & Sons, New York, 2005. [7] J. J. H. Wang, "An examination of the theory and practices of planar near-field measurement", IEEE Trans. Antennas Propagat., vol. 36, pp. 746-753, Jun. 1988. [8] A. C. Newell, R. D. Ward, and E. J. McFarlane, "Gain and power parameter measurements using planar near- 632
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THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 7, Jul. 2016. TRM 1998 2: () 2000 8: () 2000 8: LIG [ 주관심분야 ] / 1995 2: ( ) 1997 2: ( ) 2001 8: () 2001 11: LIG [ 주관심분야 ],,, 634