THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. 2015 May; 26(5), 435444. http://dx.doi.org/10.5515/kjkiees.2015.26.5.435 ISSN 1226-3133 (Print)ISSN 2288-226X (Online) 77 GHz A Virtual Array Design of 77 GHz Vehicle Radar for Detecting Moving Targets 김두수 홍동희 주정명 양진모 이상인 Doo-Soo KimDong-Hee HongJeong-Myeong Joo*Jin-Mo YangSang-In Lee 요약 77 GHz.,,. 10 db.,. (30 +30 ) ( com =0 ), 1015 db. Abstract This paper specifies on a virtual array design of a 77 GHz vehicle radar for detecting a moving target at a time division transmit and a near range. The virtual array designed reduces a hardware complexity, weight and price. However, a synthesized beam of the virtual array has a high side lobe by a phase distortion of receive signals when the moving target is detected at the time division transmit. For this, a subarray receive signal with a same phase is used and the side lobe of the synthesized beam is suppressed above at least 10 db. Also the virtual array has a beam distortion by a spherical wave when the vehicle radar operates at near range. So a boresight receive signal of each target range is compensated at each receive signal. Therefore the synthesized beam with compensation recovers a normal main lobe and improves the side lobe about 1015 db. Key words: Vehicle Radar, Virtual Array, Time Division Transmit, Near Range Beam Forming, Compensation. 서론,. [1] RF(Radio Frequency) (transmit receive module) (Agency for Defense Development) *LIG (LIG Nex1) Manuscript received November 14, 2014; Revised April 7, 2015 ; Accepted April 13, 2015. (ID No. 20141114-094) Corresponding Author: Doo-Soo Kim (e-mail: dsoo@add.re.kr) c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved. 435
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 5, May 2015. [2],[3].,,. (target resolution),.,. (virtual array) [4]..,.,.,,.. λ,. 10 λ, [4],[6],[7].,.,, [4],[6]. [7],. multiplicative [8],[9],,. (false target)., multiplicative.. 2, 3. 4, 5.. 가상배열 (Virtual Array) 개념 1. M N, 1 MN. (1) (array factor). sin sin sin sin sin (1) 436
77 GHz 그림 1. Fig. 1. Virtual array structure.,,, m n,. (2-way). 2 5 12 12 60. 0.6 λ 35 db taylor. M+N MN+1 그림 2. Fig. 2. Synthesized antenna beam of virtual array.,.. 이동표적탐지가상배열설계 3-1 시분할송신에의한표적신호위상왜곡 (orthogonal waveform),. 2.. 3. (2). ( ), (m, n), (M, N) (pulse duration) (T). (2) floor. 437
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 5, May 2015. 그림 3. Fig. 3. Phase distortion by target movement. for. 4 5(M==5) 12(N=12) ( ) +28, 0, 28 m/s. M, N. (+28 m/s) (28 m/s). (2) 그림 5. Fig. 5. Synthesized antenna beam by phase distortion characteristic. 5 4..,,. ±28 m/s 5,., (false alarm). 3-2 부배열수신신호를이용한안테나빔부엽개선 그림 4. Fig. 4. Phase distortion characteristic by movement velocity of target.. M N MN N. 4 M, N 438
77 GHz 그림 6. ( /) Fig. 6. Synthesized antenna beam of virtual array(before/after subarray beam applied).. N (3). (3) MN, N. P(m, n) (2), MN N. (1). sin sin sin sin 6 (3) +28 m/s /. 35 db taylor. ( ) (null) 10 db. (3) 그림 7. ( ) Fig. 7. Synthesized multi beam of virtual array(after subarray beam applied).. (false alarm rate). 7 +28 m/s. ±30,,.. 근거리표적탐지가상배열설계 4-1 근거리표적에의한위상왜곡. 8, y ( ) ( ) P. P (spherical coordinate) 439
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 5, May 2015. 그림 8. Fig. 8. Geometrical arrangement of array element for E-field approximation. (r), (, θ=90 ) y ( ). (4) (binomial expansion),, (4) y [5]. sin cos sincos (4) P.,. λ/16 (R) (4-1) (4-2) [5]. (4-1), (4-2). D. (4-1) 그림 9. Fig. 9. Relative range distribution between targe and array elements for each target range. (4-2). sin sin for for (4-1) cos (4-2) 9 (4-2) (=0 ). 5 12, 2 m, 3 m, 4 m., 10. 77 GHz. (5) (4-2).. 440
77 GHz 그림 10. Fig. 10. Relative phase distribution among array elements for each target range. sin (5) 11 12 (5) +28 m/s 30. (main lobe) (shape),,. 2 그림 12. (30 ) Fig. 12. Synthesized antenna beam for each target range(30 degree scan beam)... 4-2 근거리표적에대한안테나빔보정 8 (r) (, θ=90 ).,. sin (6) 그림 11. ( ) Fig. 11. Synthesized antenna beam for each target range (boresight beam). (6). (5),. (=0 ), com =0. 13 14 30. 11 12 441
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 26, no. 5, May 2015. 그림 13. ( ) Fig. 13. Compensated antenna beam for each target range (boresight beam). 그림 15. (: 3 m) Fig. 15. Synthesized multi beam with compensation (target range: 3 m).. (: +) (: ).. 결론 그림 14. (30 ) Fig. 14. Compensated antenna beam for each target range (30 degree scan beam).,. (=0 ) 1015 db. ±60. 30 db,. 15 3 m. ±30. 77 GHz.,,.. ( ) 10 db.,,.. 442
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