• Title, Summary, Keyword: Monostatic RCS

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Monostatic RCS Measurement for Dielectric Barrier Discharge Plasma (유전체 장벽 방전 플라즈마의 Monostatic 레이다 단면적 측정)

  • Lee, Hyunjae;Jung, Inkyun;Ha, Jungje;Shin, Woongjae;Yang, Jin Mo;Lee, Yongshik;Yook, Jong-Gwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.3
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    • pp.246-252
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    • 2016
  • In this paper, reduction of monostatic RCS by DBD plasma is measured. For the calibration of monostatic RCS, S-parameters of two metallic plate in different sizes are used and the result is within 0.4 dB error. Metallic plate is put behind DBD plasma generator for measuring reduction of monostatic RCS by DBD plasma. To prevent arc discharge between metallic plate and DBD plasma generator, measurement is progressed spacing the interval between metallic plate and DBD plasma generator. As a result, maximum reduction of monostatic RCS is about 3 dB at 7.4 GHz.

Performance Comparison for Radar Target Classification of Monostatic RCS and Bistatic RCS (모노스태틱 RCS와 바이스태틱 RCS의 표적 구분 성능 분석)

  • Lee, Sung-Jun;Choi, In-Sik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.12
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    • pp.1460-1466
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    • 2010
  • In this paper, we analyzed the performance of radar target classification using the monostatic and bistatic radar cross section(RCS) for four different wire targets. Short time Fourier transform(STFT) and continuous wavelet transform (CWT) were used for feature extraction from the monostatic RCS and the bistatic RCS of each target, and a multi-layered perceptron(MLP) neural network was used as a classifier. Results show that CWT yields better performance than STFT for both the monostatic RCS and the bistatic RCS. And, when STFT was used, the performance of the bistatic RCS was slightly better than that of the monostatic RCS. However, when CWT was used, the performance of the monostatic RCS was slightly better than that of the bistatic RCS. Resultingly, it is proven that bistatic RCS is a good cadndidate for application to radar target classification in combination with a monostatic RCS.

Monostatic RCS Reduction by Gap-Fill with Epoxy/MWCNT in Groove Pattern

  • Choi, Won-Ho;Jang, Hong-Kyu;Shin, Jae-Hwan;Song, Tae-Hoon;Kim, Jin-Kyu;Kim, Chun-Gon
    • Journal of electromagnetic engineering and science
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    • v.12 no.1
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    • pp.101-106
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    • 2012
  • In this study, we investigated the effect of groove pattern and gap-fill with lossy materials at 15 GHz frequency of Ku-band. We used Epoxy/MWCNT composite materials as gap-fill materials. Although epoxy does not have an absorbance capability, epoxy added conductive fillers, which are multi-walled carbon nanotubes (MWCNT), can function as radar absorbing material. Specimens were fabricated with different MWCNT mass fractions (0, 0.5, 1.0, 2.0 wt%) and their permittivity in the Ku-band was measured using the waveguide technique. We investigated the effect of gap-fill on monostatic RCS by calculating RCS with and without gap-fill. For arbitrarily chosen thickness and experimentally obtained relative permittivity, we chose the relative permittivity of MWCNT at 2 wt% (${\varepsilon}_r$=8.8-j2.4), which was the lowest reflection coefficient for given thickness of 3.3 mm at V-pol. and $80^{\circ}$ incident angle. We also checked the monostatic RCS and the field intensity inside the groove channel. In the case of H-pol, gap-fill was not affected by the monostatic RCS and magnitude was similar with or without gap-fill. However, in the case of V-pol, gap-fill effectively reduced the monostatic RCS. The field intensity inside the groove channel reveals that different RCS behaviors depend on the wave polarizations.

RCS Analysis for Improving the Performance of the Skin Tracking of KSLV-II (한국형 발사체의 스킨 추적 성능 향상을 위한 RCS 분석)

  • Lee, Hyun-Seung;Lee, Eun-Gyu;Lim, Jeong-Taek;Choi, Jee-Hwan;Kim, Chul-Young
    • Journal of IKEEE
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    • v.19 no.4
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    • pp.566-572
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    • 2015
  • In this paper, we calculate monostatic RCS(Radar Cross Section) and bistatic RCS for improving the Performance of the skin tracking of KSLV-II and the results were compared. EM(Electromagnetic) simulator was used for numerical analysis. For the two paths(L, S), after the vehicle was launched, RCS was calculated for region from 280 to 400 seconds. In the case of using the bistatic radar system, when the vehicle was launched to the L path, tracking performance was better when we receive RCS in Jeju than in Goheung. When the vehicle was launched to the S path, tracking performance was better when we receive RCS in Goheung than in Jeju. In the case of using the monostatic radar system, when the vehicle was launched to the L path, tracking performance was better when we receive RCS in Goheung than in Jeju. When the vehicle was launched to the S path, tracking performance was better when we receive RCS in Jeju than in Goheung.

Effect of Plasma Area on Frequency of Monostatic Radar Cross Section Reduction

  • Ha, Jungje;Shin, Woongjae;Lee, Joo Hwan;Kim, Yuna;Kim, Doosoo;Lee, Yongshik;Yook, Jong-Gwan
    • Journal of electromagnetic engineering and science
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    • v.17 no.3
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    • pp.153-158
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    • 2017
  • This work reports on the effect of plasma area on the frequency characteristics of the monostatic radar cross section (RCS) of a square metallic plate. A dielectric barrier discharge (DBD) plasma actuator consisting of 10 rings is proposed. The actuator is fabricated in three different configurations such that only three inner rings, seven inner rings, and all rings can be biased. By applying an 18-kV bias at 1 kHz, the three types of DBD actuators generate plasma with a total area of 16.96, 36.74, and $53.69cm^2$, respectively, in a ring or circular form. The experimental results reveal that when the DBD actuator is placed in front of a $20mm{\times}20cm$ conducting plate, the monostatic RCS is reduced by as much as 18.5 dB in the range of 9.41-11.65 GHz. Furthermore, by generating the plasma and changing the area, the frequency of maximum reduction in the monostatic RCS of the plate can be controlled. The frequency is reduced by nearly 20% in the X band when all rings are biased. Finally, an electromagnetic model of the plasma is obtained by comparing the experimental and full-wave simulated results.

A study on phi directional Monostatic RCS reduction of aluminum plate using RF probe in X-band (X-band 에서의 RF 프로브를 이용한 알루미늄판의 Phi방향 Monostatic RCS 감쇄연구)

  • Hwang, Joo-Sung;Park, Sang-Bok;Cheon, Chang-Yul;Chung, Young-Seek
    • Proceedings of the KIEE Conference
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    • pp.1656-1657
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    • 2011
  • 본 논문에서는 RF 프로브를 이용하여 평면 구조물의 RCS(Radar Cross Section)를 감쇄시키기 위한 방법을 제안하였다. 우선적으로, EM 시뮬레이터를 이용하여 제안한 방법에 대한 가능성을 증명한 후 실험을 수행하였다. x-band 에서 $10{\lambda}$의 알루미늄판 위에 FR4 기판을 이용하여 patch 형태로 제작된 RF 프로브를 설치하였으며, 그 후 알루미늄 판으로 입사되는 외부 전자파를 상쇄시키기 위하여 RF 프로브로부터 전자파를 방사하였다. 로테이터를 사용하여 알루미늄판을 phi 방향으로 회전하여 임의의 각도로 입사하는 평면파에 대해서도 반사파의 크기를 측정하였다. RF 프로브로부터 방사된 전자파의 세기와 위상은 신호 발생기와 위상 천이기를 이용하여 조절되었다. 결과적으로 무반향실에서의 실험을 통해, 알루미늄판에 의해 반사되는 전자파를 측정하여 외부 전자파의 상쇄 정도를 확인하였다.

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Study on the Performance Enhancement of Radar Target Recognition Using Combining of Feature Vectors (특성 벡터 융합을 이용한 레이더 표적 인식 성능 향상에 관한 연구)

  • Lee, Seung-Jae;Choi, In-Sik;Chae, Dae-Young
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.9
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    • pp.928-935
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    • 2013
  • This paper proposed a combining technique of feature vectors which improves the performance of radar target recognition. The proposed method obtains more information than monostatic or bistatic case by combining extracted feature vectors from two receivers. For verifying the performance of the proposed method, we calculated monostatic and bistatic RCS(BRCS) of three full-scale fighters by changing the receiver position. Then, the scattering centers are extracted using 1-D FFT-based CLEAN from the calculated RCS data. Scattering centers are used as feature vectors for neural network classifier. The results show that our method has the better performance than the monostatic or bistatic case.

A Study on Phi Directional Monostatic RCS Reduction of the Aluminum Plate using the Oscillation System (Oscillation System을 이용한 알루미늄판의 Phi방향 Monostatic RCS 감쇄 연구)

  • Hwang, Joosung;Park, Sangbok;Jang, Sunghoon;Cheon, Changyul
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.2
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    • pp.228-231
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    • 2013
  • This paper proposes a new method that reduces RCS(rader cross section) of the aluminum plate using a oscillation system composed of a VGA(variable gain amplifier) and a phase shifter. Once the oscillation system receives the external-RF signal through a probe on aluminum plate, it makes an amplified signal with a specific phase to cancel the signal reflected from the aluminum plate. The signal transmitted from the oscillation system has the same amplitude and out of phase with the reflected signal. And it can be controlled by the VGA and the phase shifter in the oscillation system. In order to validate the performance of the proposed oscillation system, FEM simulator was used and we measured how much an amplitude of the signal reflected from the aluminum plate rotated in phi direction is reduced in an anechoic chamber.

Resonance Frequency Extraction of Full-scale Radar Targets Using Time-Frequency Analysis (시간-주파수 해석법을 이용한 실스케일 레이더 표적의 공진주파수 추출)

  • Kim, In-Ha;Choi, In-Sik
    • 한국정보기술학회논문지
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    • v.15 no.6
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    • pp.87-94
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    • 2017
  • The resonance frequency is observed in the late-time response of radar signal, and it is a unique frequency determined by the physical length of the target. In this paper, we conducted a simulation in the HF band of 0.2 ~ 28 MHz to observe the resonance frequency. First, the RCS(radar cross section) of four full-scale targets were obtained using RCS analysis tool FEKO. Then, results for resonance frequency extraction were compared and analyzed using the time-frequency analysis methods such as CWT(Continuous Wavelet Transform) and AWT(Adaptive Wavelet Transform). The radar structure was considered in the monostatic and bistatic $150^{\circ}$. By the comparison of the results, we can see that the resonance frequencies extracted from the two techniques are almost same, but the resolution in the time and frequency domain is better in the case of the AWT.

Planar Active Rectrodirective Array With Subharmonic Phase Conjugation Mixers

  • Kim Gi-Rae;Park Ji-Yong
    • Journal of information and communication convergence engineering
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    • v.2 no.3
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    • pp.153-156
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    • 2004
  • A planar active retrodirective four-element array with subharmonic phase conjugation mixers based on anti-parallel diode pairs (APDPs) is proposed. As compared to previous phase conjugation mixers using twice RF frequency for LO frequency, the proposed conjugation mixers need only half RF frequency so that it can be easily applied for millimeter-wave applications. Receiving, transmitting, local oscillator, and intermediate frequencies are 5.79, 5.81, 2.9 GHz, and 10 MHz. Monostatic RCS and Bistatic RCS measurements at source locations of $0^{\circ},\;-20^{\circ},\;and\;28^{\circ}$ show good agreement with the calculated data.