THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. 2016 Oct.; 27(10), 926 934. http://dx.doi.org/10.5515/kjkiees.2016.27.10.926 ISSN 1226-3133 (Print) ISSN 2288-226X (Online) Multi-Function Compact Frequency Synthesizer for Ka Band Seeker 안세환 이만희 김홍락 Se-Hwan An Man-Hee Lee Hong-Rak Kim 요약 Ka. DDS,., 0.45 μsec, 1 khz (offset) 93.69 dbc/hz, 120(width) mm 120(length) mm 22(height) mm. Abstract In this paper, we designed a compact frequency synthesizer with multi-function for Ka-band seeker. DDS(Direct Digital Synthesizer) is applied to generate various waveform and to cover high-speed frequency sweep. In order to reduce size, waveform generator and frequency up-converter are integrated in one module. Proposed frequency synthesizer provides precise detection and tracking waveform for low and high speed targets. It is observed that fabricated synthesizer performs 0.45 μsec frequency switching time and 93.69 dbc/hz phase noise at offset 1 khz. The size of the synthesizer is kept within 120 mm width, 120 mm length and 22 mm height. Key words: Ka-Band, Frequency Synthesizer, DDS, Multi-Function Waveform. 서론.,,..,,,.,, [1]. / / LIG. LIG/(Seeker & EO/IR R & D Lab, LIG Nex1) Manuscript received June 10, 2016 ; Revised September 6, 2016 ; Accepted October 7, 2016. (ID No. 20160610-063) Corresponding Author: Se-Hwan An (e-mail :an.se.hwan@lignex1.com) 926 c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.
/,.,,.,,, [2]. PLL(Phase Locked Loop),,,,, VCO [2].,,, VCO.,.,. LFM (Linear Frequency Modulation) FMCW(Frequency Modulation Continuous Wave).,.. 주파수합성기설계방안 1. 1 Ka band,, -1,2. 1 10 9 /g, 100 MHz TCXO. TCXO Ka PLVCO, SRD(Step Recovery Diode) - 1 AD9910 900 MHz( ), 2.1 GHz. 표 1. Table 1. Specification of frequency synthesizer. Frequency step size Phase noise(offset 1 khz) Ka-band±250 MHz 5 MHz 1 μsec +13 dbm±3 db LFM, FMCW 80 dbc/hz 40 dbc 50 db 그림 1. Fig. 1. Block diagram of frequency synthesizer. 927
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 10, Oct. 2016. 그림 2. DDS Fig. 2. Waveform diagram of DDS. -1 AD9910 150 MHz 125 MHz, LFM, FMCW, CW. AD9910 DDS 2, DDS ( ) Δt. Δt. Δt 4.4 nsec AD9910 900 MHz. (Δt) [3]. (a) LFM (a) Measured LFM waveform 기준신호 (1) 주파수스텝 출력주파수 AD 9910 2.1 GHz, Ka IF. DQM(Direct Quadrature Modulator). DQM. -2 AD9913 FMCW, CW LO2. AD9910 AD9913, 2x MHz 10 MHz. x.0 GHz LO2. LO2 LO, CW FM- CW. 3, 4 DDS data (2) (b) FMCW (b) Measured FMCW waveform (c) (c) Measured phase noise 그림 3. -1 Fig. 3. Measured result of output waveform & phase noise at direct digital frequency synthesizer-1. 928
(a) FMCW (a) Measured LFM waveform (b) (b) Measured phase noise 그림 4. LO2 Fig. 4. Measured result of LO2 output waveform & phase noise. -1 LFM, FMCW -2(LO2 ) FMCW. Ka PLVCO -1 4 3x.x GHz 500 MHz TX 3x.x GHz LO1. TX TX, PILOT, TCE. TX VVA (Voltage Variable Attenuator) 50 db TX., Ka CW Pulse. Ka PLDRO(Phase Locked Dielectric Resonator) PLVCO(Phase Locked Voltage Controled Oscillator), Ka. Ka PLVCO -1. PLVCO x GHz 2 Ka F 0 F 0 /2. 4 x GHz Ka, 500 MHz. 50 db VVA(Voltage Variable Attenuator). 5 PLVCO, F 0 1 khz (offset) 94 dbc/hz, F 0 /2 1 khz (offset) 100.7 dbc/hz. Ka -1 PLVCO 4, -1 PLVCO 10 dbc Ka PLVCO. PLVCO 4. 2 VCO offset., 1 khz (offset) 82 dbc/hz. Ka Ka CPW(Coplanar Waveguide). Ka,,., 929
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 10, Oct. 2016. 파수 생성부에서는 캐리어간 연결 및 전송선로 연결 시 CPW 형태의 구조를 이용하였다. [4] Ⅲ. 주파수 합성기 제작 및 측정결과 상기 설계 내용을 바탕으로 주파수 합성기를 120 120 22 mm 크기로 제작하였고, 그림 6은 Ka 대역 주파수 합 성기 제작 결과이다. 파형 발생부는 FR4를 이용하여 제 작하였고, Ka 대역 생성부의 증폭기 스위치 등 능동소자 는 부품들의 성능 검증이 우선 수행되어야 하기 때문에 캐리어 형태로 제작하여 성능 검증 후 삽입하였고, 여파기 와 부품들 연결기판은 Duroid-6010을 사용하여 제작하였다. 그림 7은 TX 신호의 출력 전력, 주파수 스위칭 속도, 3 위상잡음 측정 결과 (a) F0 (a) Measured phase noise of F0 위상잡음 측정 결과 (b) F0/2 (b) Measured phase noise of F0/2 위상잡음 측정 결과 그림 5. PLVCO Fig. 5. Measured result of PLVCO phase noise. 파형발생부 (a) (a) Waveform generation part 위상잡음 예측 표 2. Ka band Table 2. Estimated phase noise at Ka band. 측정 결과 PLVCO (dbc/hz) Offset 100 Hz 1 khz 3 khz 10 khz 100 khz 1 MHz F0 81.2 94.6 96.1 97.7 102.7 126 F0/2 89.2 100.7 102.3 103.5 107.9 130.2 최종 출력 예측 결과 (dbc/hz) F 4체배 F /2 4체배 69.2 77.2 82.6 88.7 84.1 90.3 85.7 91.5 90.7 95.9 114.0 118.2 0 0 합으로 인해 주파수가 높아질수록 반사손실이 커지게 된 다. 부정합으로 발생하는 손실을 줄이기 위해 Ka 대역 주 930 대역 생성부 (b) Ka (b) Ka band signal generation part 대역 주파수 합성기 제작 형상 그림 6. Ka Fig. 6. Fabricated Ka band frequency synthesizer.
(a) TX (b) (a) Output power & flatness of TX (b) Frequency switching time (c) TX (c) Phase noise of TX (d) Tx (d) Maximum variable output power of TX (e) (e) Spurious 그림 7. TX Fig. 7. Measured result of TX signal. 931
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 10, Oct. 2016., VVA (),.., 0 Hz(f o ). +5 MHz 5 MHz. 0.456 μsec PLL. 2 1 khz (offset) 93 dbc/hz, 100 khz (offset) 98 dbc/hz. +12.9 dbm±1.0 db, 44 dbc, 52 db. 8 Ka LO1. +15.2 dbm±0.5 db, LO1 TX 100 dbc. LO1 TX /, LO1 TX., TX 표 3. Table 3. Measured values of frequency synthesizer. Ka band±250 MHz Ka band±250 MHz 5 MHz 5 MHz 1 μsec 0.456 μsec +13 dbm±3 db +12.9 dbm±1 db LFM, FMCW LFM, FMCW Phase noise (Offset 1 khz) 80 dbc/hz 93 dbz/hz 40 dbc 44 dbc 50 db 52 db() (a) LO (a) Output power & flatness of LO (b) LO1 ( ) (b) Output power level(center frequency) of LO1 (c) LO1 ( ) TX (c) TX leakage output power at LO1(center frequency) 그림 8. LO1 Fig. 8. Measured result of LO1 signal. 932
표 4. Table 4. Performance comparison of frequency synthesizer. [GHz] [dbc/hz] @1 khz @10 khz [MHz] [MHz] Lock time [dbc] [5] 35 83-400 40 15 us 62 [db] [6] 35.0 48 48 500 8 2 ms 43 CW [7] 3x.x 68.6 93.6 500 10 : 52 CW 0.7 us This work 3x.0 93 98.0 500 5 : 0.5 us 44 52 CW CW, LFM, FMCW. 3,. 4,, DDS chip, PLL,,.. 결론 DDS chip AD9910 AD9913 DDS., 120 120 22 mm 3, CPW Ka.,. References [1] James A, Crawford, Frequency Synthesizer Design Handbook, Artech House. 1994. [2],, " ",, 1997. [3] AD9910, AD9913 datasheet, Analog Devices. Inc. Available : http://www.analog.com [4],,, " CBFGCPW - microstrip MIC ", pp. 809-818, 18(7), 2007. [5] M. Xiaohua, D. Hao, J. Chuangxin, and M. Fan, "A low phase-noise Ka-band frequency synthesizer", Microwave Conference Proceeding, pp. 1-3, 2011. [6],,,, " Ka- ",, 18(5), pp. 511-521, 2007 5. [7], " Ka ",, 18(5), pp. 511-521, 2011 11. 933
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 27, no. 10, Oct. 2016. 2004 2 : () 2006 2 : ( ) 2007 1 : LIG( ) [ 주관심분야 ],, 1995 2 : () 1997 8 : ( ) 1997 7 : LIG( ) [ 주관심분야 ],,, 2007 2 : () 2009 2 : ( ) 2009 1 : LIG( ) [ 주관심분야 ], 934