A multiple frequency cancellation(MFC)method is proposed for stealth design of ultra-wide band(UWB)end-fire antenna array.The proposed method can produce significant radar cross section(RCS)reduction in the whole oper...A multiple frequency cancellation(MFC)method is proposed for stealth design of ultra-wide band(UWB)end-fire antenna array.The proposed method can produce significant radar cross section(RCS)reduction in the whole operating band.The 1×4 and 4×4 Vivaldi antenna arrays of different kinds of cancellation structures are discussed as examples to validate the effectiveness of the MFC method on both linear and planar arrays.On average,22.6 dB reduction of monostatic radar cross section(MRCS)is obtained in the whole X-band.MRCS under oblique incident waves is also reduced within±60°.Basically favorable radiation characteristics are maintained.展开更多
The Transmit BeamForming (TBF) technology, applied in a multiple-transmit radar system, is studied in this paper, where multiple elements of antenna array transmit binary Zero Correlation Zones Orthogonal Signals (ZCZ...The Transmit BeamForming (TBF) technology, applied in a multiple-transmit radar system, is studied in this paper, where multiple elements of antenna array transmit binary Zero Correlation Zones Orthogonal Signals (ZCZ-OS) independently. For each Direction Of Arrival (DOA) with respect to the transmitting array, the analysis on the gain and sidelobe level of TBF output is presented. This paper focuses on the range sidelobes performance within the main beam (in angle domain). For the normal direction, due to the inherent phase property of ZCZ-OS, the TBF output has part zero sidelobes area, of which the distribution is discussed. For the other directions, a systematic search algorithm to optimize the transmission order of signals is proposed for an optimal relationship chart of DOA and transmission order. The range sidelobe performance within the main beam can be improved as the optimal transmission order is adopted.展开更多
In terms of the coupled mode theory, microring resonance and electro-optic modulation princeple, a reasonable project is proposed for designing an electro-optic switch with the series-coupled multiple microring resona...In terms of the coupled mode theory, microring resonance and electro-optic modulation princeple, a reasonable project is proposed for designing an electro-optic switch with the series-coupled multiple microring resonators. The simulation and optimization are performed at the resonant wavelength of 1550 nm. The results are as follows: the core size of the microring is 1.6 μm×1.6 μm, the confined layer between the core and the electrode is 1.6 μm, the thickness of the electrode is 0.15 μm, the radius of the microring is 15.2 μm, the coupling gap between the microring and the channel is 0.14 μm, and the one between the microring and the microring is 0.6 μm, microring number M is 4, the switching voltage is 4 V, the insertion loss is 5.4 dB, and the crosstalk is –20 dB. The output spectrum is much flatter and much steeper than that of the single microring.展开更多
在军事领域中,机载多输入多输出(multiple input multiple output,MIMO)雷达既要探测机动目标,又要防止被截获接收机侦收。针对这一问题,提出了低截获的单基地非均匀阵列MIMO雷达改进多信号分类(multiple signal classification,MUSIC)...在军事领域中,机载多输入多输出(multiple input multiple output,MIMO)雷达既要探测机动目标,又要防止被截获接收机侦收。针对这一问题,提出了低截获的单基地非均匀阵列MIMO雷达改进多信号分类(multiple signal classification,MUSIC)算法。通过对MIMO雷达匹配滤波后的接收信号进行降维处理、白化处理、时频分析、时频点筛选、正交联合对角化等信号处理,实现了低信噪比(signal to noise ratio,SNR)、低信号持续时间下的方向角估计。研究结果表明,在相同环境下,与MIMO雷达时频MUSIC算法相比,低截获MIMO雷达改进MUSIC算法空间谱指向精度有所提高,可分辨角度差仅为1°的相邻目标,适用SNR降低2 dB且保证了低截获性能。展开更多
基金supported in part by Nanjing University of Aeronautics and Astronautics Research Funding(No. Kfjj20150414)。
文摘A multiple frequency cancellation(MFC)method is proposed for stealth design of ultra-wide band(UWB)end-fire antenna array.The proposed method can produce significant radar cross section(RCS)reduction in the whole operating band.The 1×4 and 4×4 Vivaldi antenna arrays of different kinds of cancellation structures are discussed as examples to validate the effectiveness of the MFC method on both linear and planar arrays.On average,22.6 dB reduction of monostatic radar cross section(MRCS)is obtained in the whole X-band.MRCS under oblique incident waves is also reduced within±60°.Basically favorable radiation characteristics are maintained.
基金Supported by the Major State Basic Research Development Program of China(973Program)(No.2011CB-707001,2010CB731903)Changjiang Scholars and Innovative Research Team in University(IRT0954)the National Natural Science Foundation of China(No.60971108,60825104)
文摘The Transmit BeamForming (TBF) technology, applied in a multiple-transmit radar system, is studied in this paper, where multiple elements of antenna array transmit binary Zero Correlation Zones Orthogonal Signals (ZCZ-OS) independently. For each Direction Of Arrival (DOA) with respect to the transmitting array, the analysis on the gain and sidelobe level of TBF output is presented. This paper focuses on the range sidelobes performance within the main beam (in angle domain). For the normal direction, due to the inherent phase property of ZCZ-OS, the TBF output has part zero sidelobes area, of which the distribution is discussed. For the other directions, a systematic search algorithm to optimize the transmission order of signals is proposed for an optimal relationship chart of DOA and transmission order. The range sidelobe performance within the main beam can be improved as the optimal transmission order is adopted.
基金supported by the National Natural ScienceFoundation of China (60706011)the National "973" Project ofChina(2006CB302803)+1 种基金the Fund of Chinese Ministry of Educa-tion (20070183087)the Fund of Science and Technology ofJilin Province of China(20080125).
文摘In terms of the coupled mode theory, microring resonance and electro-optic modulation princeple, a reasonable project is proposed for designing an electro-optic switch with the series-coupled multiple microring resonators. The simulation and optimization are performed at the resonant wavelength of 1550 nm. The results are as follows: the core size of the microring is 1.6 μm×1.6 μm, the confined layer between the core and the electrode is 1.6 μm, the thickness of the electrode is 0.15 μm, the radius of the microring is 15.2 μm, the coupling gap between the microring and the channel is 0.14 μm, and the one between the microring and the microring is 0.6 μm, microring number M is 4, the switching voltage is 4 V, the insertion loss is 5.4 dB, and the crosstalk is –20 dB. The output spectrum is much flatter and much steeper than that of the single microring.
文摘在军事领域中,机载多输入多输出(multiple input multiple output,MIMO)雷达既要探测机动目标,又要防止被截获接收机侦收。针对这一问题,提出了低截获的单基地非均匀阵列MIMO雷达改进多信号分类(multiple signal classification,MUSIC)算法。通过对MIMO雷达匹配滤波后的接收信号进行降维处理、白化处理、时频分析、时频点筛选、正交联合对角化等信号处理,实现了低信噪比(signal to noise ratio,SNR)、低信号持续时间下的方向角估计。研究结果表明,在相同环境下,与MIMO雷达时频MUSIC算法相比,低截获MIMO雷达改进MUSIC算法空间谱指向精度有所提高,可分辨角度差仅为1°的相邻目标,适用SNR降低2 dB且保证了低截获性能。
