• Title/Summary/Keyword: Side-lobe level

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Design of slotted waveguide antenna with slot depth variation (슬롯깊이 변화에 따른 도파관 슬롯 안테나의 설계)

  • Kim, Gue-Chol
    • The Journal of the Korea institute of electronic communication sciences
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    • v.8 no.4
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    • pp.535-540
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    • 2013
  • We design a slotted waveguide antenna for X-band which a 1.4m length with slot depth variation. A 54 slot array is modeled and simulated by CST, and the side lobe level is suppressed effectively in a certain range of frequency. The experimental results of the antenna show that its gain, maximum sidelobe level and half power beam-width are 21.8dB, -31dB and 2.0deg, respectively.

Initial-phase Sensitivity Analysis of Harmonic Measurements via Windowed DFT

  • Song, Shuping;Wang, Fuzong;Cheng, Guozhu
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.4
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    • pp.182-188
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    • 2014
  • When the windowed DFT algorithm is applied in harmonic measurements, the problem of initial-phase sensitivity will be encountered, this has an effect on harmonic amplitude accuracy. In this paper, the origin of initial-phase sensitivity is analyzed and the main factors that influence the level of initial-phase sensitivity are demonstrated. A method of reducing initial-phase sensitivity is proposed to increase the stability of harmonic measurements. We found that initial-phase sensitivity is determined by the side lobe peak level of the window functions when synchronous deviation is fixed. In addition, increasing the length of the time recorded can be used to remove initial-phase sensitivity. The correctness and validity of our conclusions have been confirmed through numerical results and field tests.

Analysis of Effects of Phase Noise in Radar System (위상잡음이 레이더 시스템에 미치는 영향 분석)

  • Park, Jinsung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.16 no.3
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    • pp.373-381
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    • 2013
  • In this paper, the effects of phase noise on the radar system were analyzed in terms of 3 point of view. The impact(s) on the compressed pulse waveform, the FMICW(Frequency Modulated Interrupted Continuous Wave) radar performance and the receiver sensitivity were investigated. From the investigation, it was indicated that the phase noise over 10 kHz offset frequency makes the side lobe level of compressed pulse worse. Also it was founded that the FMICW radar performance, especially at the noise level of range profile, is related to the phase noise. Finally, the investigation showed that the phase noise at local oscillator affects the receiver sensitivity.

Design of Microstrip Array Antenna with Three-Element Sequential-Rotation Subarray for DBS

  • Jin, Kyung-Soo;Shin, Hye-Jung;Park, Byong-Woo
    • Journal of electromagnetic engineering and science
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    • v.2 no.1
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    • pp.28-33
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    • 2002
  • The LHCP circularly polarized antenna operating at DBS band is developed by employing the sequential-rotation technique in which each subarray is comprised the three truncated-corner patch square element. Antenna designed with sequentially-related technique whose M=3, p=2 has the effect of improved axial-ratio bandwidth, cross-polarization etc. And it is proved that the degradation of radiation pattern can be reduced significantly by minimizing the radiation loss of feeding line structure. Antenna designed shows extremely low side lobe level of below - 25 dB in the diagonal plane and cross-polarization level of below -20 dB in the all plane. And these performances comply with the array antenna specification for DBS.

A Study on Wideband Adaptive Beamforming using Taylor Weighting and LSMI Algorithm (Taylor 가중치와 LSMI 알고리즘을 이용한 광대역 적응형 빔형성 연구)

  • Oh, Kwan-Jin;Lee, Hee-Young;Kim, Seon-Joo;Chung, Young-Seek;Cheon, Changyul
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.3
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    • pp.380-386
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    • 2013
  • This paper represents an adaptive beamforming technique to suppress interference or jamming signals in wideband. In order to maintain low side lobe level(SLL) at an antenna element level, Taylor-weighting was used. Also, to make a nulling beam pattern toward jammer's directions in wideband, we used the modified Loaded Sample Matrix Inversion(LSMI) algorithm and Tapped Delay Line(TDL). To verify the proposed algorithm, we applied it to a rectangular array antenna. Finally, the results show beam pattern with low SLL and jammers suppression.

Design and Fabrication of X-band Wideband Array Antenna for SAR Applications (SAR를 위한 X-band 광대역 배열 안테나의 설계 및 제작)

  • Won Young-Jin;Lee Young-Ju;Kong Young-Kyun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.2 s.105
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    • pp.184-192
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    • 2006
  • Synthetic Aperture Radars(SAR) are used mainly for high-resolution imaging of the terrain. This paper describes the $16{\times}16$ array antenna designed for an X-band, automobile-based SAR(AutoSAR) system. This antenna has the structure of several layers such as radome, radiators, slots, feed network, and honeycomb cores. Each layer is adhesively bonded to meet different combination of structural and electrical design requirements. Using the Strip-Slot-Foam-Inverted-Patch(SSFIP) structure and honeycomb cores, a wide bandwidth and a structural hardness were achieved. Measurement results were compared with simulation results. It was observed that this antenna had a bandwidth of 1.7 GHz, side-lobe levels of less than -20 dB, half-power beamwidth of $5^{\circ}$ and $5^{\circ}$, and gains of 25.0 dBi. The observed results show that the designed array antenna will be applicable to the wideband SAR system.

The Radiation Characteristics Improvement and Thickness Reduction of Base Station Antenna with Artificial Magnetic Conductor (인공 자기 도체를 이용한 기지국 안테나의 방사 특성 개선 및 두께 감소)

  • Son, Cheol-Hong;Ahn, Ji-Hwan;Chang, Ki-Hun;Yoon, Ji-Hwan;Yoon, Young-Joong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.12
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    • pp.1233-1242
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    • 2009
  • In this paper, a Base Station Antenna(BSA) utilizing Artificial Magnetic Conductor(AMC) as reflector instead of common conductive plate to improve radiation characteristics and achieve low-profile is proposed. In the case of the conventional BSA on conductive surface which acts as a reflector, a secondary radiation is caused at the corner of the conductive surface, and it increases the back-lobe of the antenna, resulting in deteriorating the radiation characteristic of the conventional BSA. However, using the AMC, the back-lobe of the BSA can be largely reduced by the surface wave suppression. And the Side-Lobe Level(SLL) is also improved, resulting in preventing the service area overlapped. Furthermore, due to the $0^{\circ}$ reflection phase on AMC, the profile of the BSA can be also reduced.

Construction of a Microphone Array to Localize Noise Sources of Railway Trains (철도 차량의 소음원 측정을 위한 마이크로폰 어레이 설계)

  • Choi, Sung-Hoon;Noh, Hee-Min;Cho, Jun-Ho;Koh, Hyo-In
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2269-2275
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    • 2011
  • This paper deals with the design of a microphone array to measure location and spectral characteristics of railway noise sources. A microphone array estimates the direction of a noise source assumed as a point source using the delayed-sum beamforming method and its performance is determined in terms of resolution and side-lobe level. A 48 channel microphone array was already developed to measure noise sources of KTX trains and a new array with 96 microphones has been designed to enhance the performance. This paper simulates the performance the microphone arrays according to the configuration of microphones and verifies it through on-site tests.

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Interferometric Synthetic Aperture Millimeter-wave Radiometer for the High Resolution Imaging

  • Kim, Yong-Hoon;Choi, Jung-Hee;Kang, Gum-Sil
    • Proceedings of the KSRS Conference
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    • 1999.11a
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    • pp.122-126
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    • 1999
  • The imaging characteristics of a 2-D interferometric synthetic aperture radiometer, such as an angular resolution, depend largely on the type of an antenna array. In this paper, different array configurations of antenna are studied and compared with each array types to get more high resolution image in spatial. T-, X- and Y- types of antenna array are considered and the performances of each type are analyzed considering spatial resolution. The simulation results of candidate antenna types are presented in this paper. In case of Y-type the coverage area of the visibility function is wide and the angular resolution is high more than the others. X-type array shows the good performance for side lobe level.

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Fabrication and Measurement of a Micro strip-Array Antenna for the Electronic Toll Collection System (ETCS)

  • Yoon, Joong-Han;Lee, Sang-Mok;Lee, Hwa-Choon;Kwak, Kyung-Sup;Chun, Su-Mi;Byun, Woo-Sub;Jung, Myung-Nam;Shin, Dong-Hun
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.723-726
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    • 2002
  • This paper describes the design, fabrication, and measurement of a sequential-rotation microstrip-array antenna for the Electronic Toll Collection System (ETCS). The ETCS is made possible by using roadside equipment with radiation pattern that can accurately pinpoint the designated communication area, without interference from other lanes. The sequential-rotation microstrip-array antenna was applied to the absorber to reduce the side lobe level (SLL). Results showed that the antenna yields a return loss at a center frequency of -20.675 dB, an axial ratio of 1.15 dB, and a gain of 20.26 dBi.

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