IMPACT OF WIDE-BAND I/Q MODULATION ERRORS IN SAR IMAGING ANALYSIS AND COMPENSATION METHOD RESAERCH  

作　　者：Qiao Ming Wang Jie Zhou Liangjiang LI Daojing 

机构地区：[1]National Key Lab of Microwave Imaging Technology, Institute of Electronics, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Journal of Electronics(China)》2013年第3期222-230,共9页电子科学学刊（英文版）

基　　金：Supported by 863 Program (2009AA12Z103);973 Program (2009CB72400)

摘　　要：Direct quadrature modulation technology is suitable for wide-band radar signal generation. However, this method has rigorous requirements on amplitude and phase balance of the orthogonal input signals. If the requirements are not satisfied, there would be modulation errors such as image frequency and oscillator leakage that cannot be filtered. The modulation errors will therefore raise the noise floor of the range profile and reduce the dynamic range of the Synthetic Aperture Radar (SAR) image as a whole. In this paper, the wide-band In-phase/Quadrature-phase (I/Q) modulation errors are modeling analyzed, and the influence of wide-band I/Q modulation errors on SAR imaging is discussed. Furthermore, a compensation method of modulation errors is proposed, and the circuit implementation of the radar signal generation and pre-distortion is presented. The experimental results illustrate that the curves of the I/Q amplitude and phase imbalance errors are successfully extracted and the rejection of image frequency improved significantly, thus meets the requirements of the SAR imaging.Direct quadrature modulation technology is suitable for wide-band radar signal generation. However, this method has rigorous requirements on amplitude and phase balance of the orthogonal input signals. If the requirements are not satisfied, there would be modulation errors such as image frequency and oscillator leakage that cannot be filtered. The modulation errors will therefore raise the noise floor of the range profile and reduce the dynamic range of the Synthetic Aperture Radar （SAR） image as a whole. In this paper, the wide-band In-phase/Quadrature-phase （I/Q） modulation errors are modeling analyzed, and the influence of wide-band I/Q modulation errors on SAR imaging is discussed. Furthermore, a compensation method of modulation errors is proposed, and the circuit implementation of the radar signal generation and pre-distortion is presented. The experimental results illustrate that the curves of the I/Q amplitude and phase imbalance errors are successfully extracted and the rejection of image frequency improved significantly, thus meets the requirements of the SAR imaging.

关 键 词：Direct quadrature conversion Amplitude and phase unbalance Oscillator leakage Image frequency suppression Synthetic Aperture Radar (SAR) Interferometric SAR (In SAR) 

分 类 号：TN951[电子电信—信号与信息处理]