Time filter

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Zhong X.,CAS Institute of Electronics | Zhong X.,East China Research Institute of Electronic Engineering | Xiang M.,CAS Institute of Electronics | Yue H.,CAS Institute of Electronics | Guo H.,CAS Institute of Remote Sensing
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

Due to the lack of accuracy in the navigation system, deviations in the order of centimeters between the real trajectory and the measured one, called residual motion errors (RMEs), frequently appear in synthetic aperture radar (SAR) images. They usually cause azimuth defocusing and phase errors. For very high-resolution SAR imaging and repeat-pass SAR interferometry, the RME must be estimated and compensated. In the literature, the algorithms used to estimate such errors are mainly through interferometry. The error difference for the SAR image pair is calculated, and then the correction is applied either on one image, or alternatively fractions of it on both images. However, the accuracy of this approach is greatly deteriorated by the decorrelation and ground movements. In this paper, we associate the phase difference between two adjacent subaperture images with the second derivative of the RME, and propose a new algorithm to estimate the RME for individual SAR image. It exploits point-like targets distributed along the azimuth direction, and not only corrects the phase error, but also improves the azimuth focusing. Therefore, besides in airborne repeat-pass interferometry, the algorithm can also be applied in very high-resolution SAR imaging. Simulated and real SAR data are used to demonstrate its feasibility and accuracy. Its limitations and extensions are also discussed at the end of the paper. © 1980-2012 IEEE.

Cui Y.,Beijing University of Posts and Telecommunications | Dai Y.,Beijing University of Posts and Telecommunications | Yin F.,Beijing University of Posts and Telecommunications | Dai J.,East China Research Institute of Electronic Engineering | And 3 more authors.
Optics Express | Year: 2013

An intermodulation distortion suppression method based on the optical carrier band processing is demonstrated. A systematic analysis of the main optical spectrum contributors for the third-order intermodulation distortion in the nonlinear system is presented. Theoretical analysis shows that the third-order intermodulation distortion terms can cancel each other if a proper phase shifting is imposed to the optical carrier band. We experimentally demonstrate the approach with a two-tone test and a suppression of about 33 dB in the third-order intermodulation distortion is obtained. Experimental results show that an overall fundamental to thirdorder intermodulation distortion ratio of up to 64 dB is achieved and the link dynamic range is improved by 14.7 dB, compared with the conventional link without the proposed optical carrier band processing. ©2013 Optical Society of America.

Zhu H.-R.,Shanghai JiaoTong University | Zhu H.-R.,East China Research Institute of Electronic Engineering | Mao J.-F.,Shanghai JiaoTong University | Mao J.-F.,State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System
IEEE Microwave and Wireless Components Letters | Year: 2015

In this letter, an ultra-wideband common mode filter is proposed for high-speed differential signal transmission. By etching a slot in the inner patch of a double slit complementary split ring resonator (S-DBCSRR), the noise rejection bandwidth can be expanded. The equivalent circuit model and surface current distribution are given to explain the working principle of the filter. From the simulated and measured results, it is found that the fractional bandwidth of the presented filter is 92% with a noise suppression level of 20 dB, and the differential signal can propagate with little degradation. © 2001-2012 IEEE.

Xue W.,East China Research Institute of Electronic Engineering
Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011 | Year: 2011

The paper detailedly introduced the mechanical, thermal and electromagnetic properties of Aramid fiber composites. The applications of Aramid fiber composites in radar components home and abroad were analysed. According to research and design requirements, resin transfered molding (RTM) technique was selected. Exploratory research was described from selection and technological test of resin system, establishment and control of technological parameters in molding process. Also the quality and performance of the products were detected, tested and appraised. The result shows that the quality and performance of final products are excellent and can meet the design and application requirements. © 2011 IEEE.

Chen Z.,East China Research Institute of Electronic Engineering
Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011 | Year: 2011

The development of phased array radar puts ever-increasing demand on its beam steering system. Especially, for a large-scaled two-dimensional phase controlled radar, its beam steering system should provide a rapid and flexible beam steering control in order to realize a real-time control of the radar in target search and tracking. The paper presents a beam steering system with scalable basic modules made up of an integrated transceiver and receiver (T/R) modules and embedded controllers. By use of this beam steering system, a real-time beam steering control for all the elements in the antenna array can be realized. © 2011 IEEE.

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