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Gao Z.,Science and Technology on Millimeter wave Laboratory | Xiao Y.,Science and Technology on Millimeter wave Laboratory
2015 IEEE 12th International Conference on Electronic Measurement and Instruments, ICEMI 2015 | Year: 2016

Polarization diversity of conformal antenna arrays introduces uncertainty to the determination of array manifold needed for passive direction finding. Most of the previous research on direction of arrival (DOA) estimation for arrays with diversely polarized elements focused on the algorithms to estimate both the directions and polarizations of the incident waves[1][2][3]. In many applications however, knowledge of polarizations is not of interest and therefore it's possible to eliminate the uncertainty and complexity incurred by the diversity in polarizations and beam patterns among array's elements. In this article two data models are proposed for conformal array's DOA estimations. One is for single incident signal scenario, by treating the physical conformal array as one consisting of virtual uniform radiators through post-processing of received data. Another is a polarization-sensitive array manifold for DOA estimation of multi-incident signals. Simulation results validate the proposed algorithm, which has improved robustness and significantly lower computational requirements in comparison with traditional data models. The proposed algorithm is of great value in practical applications, especially those requiring real-time processing. © 2015 IEEE. Source


Xiao Y.,Science and Technology on Millimeter wave Laboratory | Li Z.,Science and Technology on Millimeter wave Laboratory
2015 IEEE 12th International Conference on Electronic Measurement and Instruments, ICEMI 2015 | Year: 2016

Terahertz focal plane imaging technology is getting increasing attention in recent years. As we known, field of view (FOV) is an important index for a focal plane imaging system. It determines the complexity of the system to some extent. While in terahertz band, its test is a difficulty due to the lack of reference data and effective instruments. Our system, a continuous wave THz focus plane imaging system, is introduced in this paper firstly. And then a test method is designed and realized by the following technology: terahertz quasi optical path design, terahertz signal acquisition, electronic three axis motion stents and so on. The method has been used for our system's FOV test. The 10°×10° results of experiments are in accord with that of theoretical analysis, which shows the effectiveness of the above method. At last of the article, a metal plate target is used to image for further verifying our method. The work of this paper may do some meaningful help in the integration of THz system. © 2015 IEEE. Source


Guo B.,Science and Technology on Millimeter wave Laboratory | Wang J.,Science and Technology on Millimeter wave Laboratory
2015 IEEE 12th International Conference on Electronic Measurement and Instruments, ICEMI 2015 | Year: 2016

Near-field measurement has more advantages than conventional far-field measurement in determination of the antenna characteristics. An improved near-field measurement method and near-far field transformation for radar cylindrical conformal array antenna is presented in this paper, in order to meet the requirements, such as wide near field scanning range, high precision of near-far field transformation, fast testing efficiency and so on. Near-filed data including amplitude and phase is measured automatically by a cylindrical scan measurement system. Considering shielding effect of cylinder, near-far field transformation which is the most important part of near-field measurement has been proposed and based on Kirchhoff integral. Calculating far-field pattern utilizes near-field data in both polarizations, vertical and horizontal, and 3D far-field pattern of radar cylindrical conformal phased array antenna is obtained finally, the characteristics of antenna are displayed and analyzed conveniently. It is shown that this method is faster and more efficient than traditional method. © 2015 IEEE. Source


Lin L.,Science and Technology on Millimeter wave Laboratory | Guosheng L.,Science and Technology on Millimeter wave Laboratory | Qi Z.,CAS Institute of Remote Sensing
2015 IEEE 12th International Conference on Electronic Measurement and Instruments, ICEMI 2015 | Year: 2016

Pulse compression technology is widely applied in radar system project, because of which can solve the dilemma between long detection range and fine range resolution. Technic of intermediate frequency echo signal processing in pulse compression radar is studied in this paper. We analysis the theory and implement method of linear frequency modulation signal pulse compression by building mathematics model, and prove its correctness and feasibility by using simulation software MATLAB. Firstly, signal processing system achieves band-pass sampling function to the chirp signal which is transmitted by radar and mixed by IF receiver. Secondly, digital down conversion (DDC) algorithm is introduced, and I/Q two channel baseband signal is obtained after DDC. Thirdly, the means of extraction after filtering is adopted, so that operation data is reduced. For avoiding signal aliasing, filtering before extraction should be used. At last, measure of matched filtering and windowing in frequency domain which can restrain range sidelobe is presented in this paper. © 2015 IEEE. Source


Jian B.,Science and Technology on Millimeter wave Laboratory | Jie Z.Y.,Science and Technology on Millimeter wave Laboratory
IET Conference Publications | Year: 2015

This paper researches the way to use polarization diversity technique with high range resolution to suppress angle glint for extended target. Firstly, the principles of polarization diversity technology and variable-polarization high resolution radar are introduced. Then this paper designs a data acquisition experiment for polarization information of extended target and analysis the experiment parameters. Finally the polarization differences of different scattering points in high resolution range profile are obtained and the shortcomings of the test are summarized. Source

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