相位控制相控阵天线方向图

基于线阵,讨论成片零点的相位控制,提出和采用快速算法、部分单元控制方法和约束非线性离散变量优化算法。试验结果验证了数学模型和仿真结果的正确性。     

时分导频位CDMA系统上行链路阵列接收到部分多址干扰抑制技术

针对时分导频位CDMA系统上行链路,本文提出了导频位辅助LMS－DRMTA算法加上部分多址干扰对消的空时联合干扰抑制接收方案,由于阵列的干扰抑制作用,其输出信号中只剩下少量强的多址干扰信号,部分干扰对消法只对阵列输出中的强多址干扰信号进行干扰估计并抑制,这样一方面大大降低了系统处理的运算量及缓存空间,另一方面又消除了因弱多址干扰估计的不准确而民的系统性能下降,并且相对于自适应全多址干扰对消有更好的系统稳定性,仿真实验表明该方案比全干扰用户对消法具有更好的干扰抑制效果。     

均匀圆阵中时空信道多径参数的估计方法

本文给出了在矢量信道冲激响应（VCIR）可以估计出来的前提下,一种基于信道参数矩阵法的二维方向角与相对时延的联合估计方法,该方法充分利用了已知的信号码形信息,给出了一种无需进行搜索的闭式解,与基于多维MUSIC或多维ESPRIT的方法相比,具有运算量小的优势。     

CDMA系统中时空综合干扰抑制的约束优化模型及其神经网络实现

本文提出了CDMA系统中抑制多址干扰(MAI)和码片间干扰(ICI)的利用智能天线和RAKE接收相结合的时空综合干扰抑制器的约束优化模型,导出了迫零均衡条件,探讨了其神经网络实现问题,并对综合干扰抑制器的性能进行了分析.     

模式匹配法分析有限圆盘地面单极天线

本文给出了一种严格分析有限尺寸圆盘地面单极天线的新方法———模式匹配法 .该方法通过在天线上、下两边平行放置两个无限大良导电平面 ,以及合理划分区域 ,使得每个分区中的场分量能够采用柱谐展开式解析表示 ,且展开系数由导体表面边界条件及分区交界处场分量连续条件加以确定 .在此基础上 ,进一步分析天线的输入阻抗等电性能 .计算结果表明 :对不同尺寸圆盘地面单极子天线 ,理论分析与文献中的实验结果均十分吻合 .同时 ,由于场量的解析表示 ,使得计算速度较快     

探地雷达中蝶形振子天线的改进

探地雷达是进行地下环境无损探测的一种有效工具,用来探测和识别地下目标,比如水管、电力线和通信线路、考古方面的保护等.然而,传统的探地雷达系统在可靠性、分辨率、探测深度等方面存在不足.因此,改善被测信号特性,设计和开发更高性能的天线就显得很有必要.本文研制了一种贴片电阻加载的蝶形振子天线,用时域有限差分方法对其进行了分析,实际应用结果表明天线具有良好的波形保真度,良好的辐射特性和屏蔽效果.可以广泛地应用于探地雷达和其它超宽带系统.     

一种有效的合成孔径雷达原始数据高倍数压缩算法

在分析分块自适应量化(BAQ)压缩数据的分布特性、量化信噪比、动态范围及其对矢量量化数据压缩性能和运算量影响的基础上,对分块自适应矢量量化(BAVQ)压缩算法进行了改进,提出了采用高比特数BAQ压缩的方案.利用改进的BAVQ算法压缩高分辨率SAR原始数据的结果表明,在相同压缩比的条件下,该文提出的改进算法可获得更大的量化信噪比.解压缩数据生成的图像可以清晰地保留图像中的细节信息.     

彩色JPEG图像的隐写分析

图像隐写分析的目的是检测图像中隐藏信息的存在性．JPEG图像的广泛使用使其成为一种重要的隐写载体，因而针对JPEG图像的隐写分析受到研究者们的广泛关注．本文基于彩色图像YCbCr颜色空间DCT系数的统计分布模型，提出一种彩色JPEG图像的隐写分析算法．通过计算载体图像和掩密图像DCT系数统计分布之间的鉴别信息，评估常见DCT域隐写术对载体图像DCT系数统计分布的改变．以统计分布模型参数为特征向量，采用支持向量机实现对载体图像和掩密图像的有效分类．实验结果表明，本文算法具有较高的检测率，性能优于使用Faxid所提出的彩色QMF统计量的隐写分析算法．     

Performance Analysis of Distributed-Antenna Communication Systems Using Beam-Hopping Under Strong Directional Interference

In order to efficiently mitigate the interference of directional jammers, we investigate a beam-hopping (BH) communication scheme, which includes slow beam-hopping (SBH) and fast beam-hopping (FBH) schemes. In the BH communication scheme, only one pair of the beams is used for transmission and it hops from one to the next according to an assigned BH pattern. In this contribution, a range of expressions in terms of the symbol error rate (SER) performance of the BH and conventional single-beam (SB) schemes have been derived, when both the downlink and uplink are considered. The SER performance of the BH scheme is compared with that of the SB scheme, for M-ary phase-shift keying (MPSK) and M-ary quadrature amplitude modulation (MQAM) signals under composite log normal shadowing/Nakagami-m fading channels. Our analysis and results show that the proposed BH scheme is suitable for communications, when several distributed antenna arrays are available around a mobile.Honglin Hu received his Ph.D in Communications and Information System from the University of Science and Technology of China, 2004. Currently he is with Future Radio, Siemens AG Communications in Munich, Germany. In Siemens, he makes researches mainly on SDMA and OFDM techniques, also on the cross-layer design and optimization for future wireless communication systems. Dr. Hu is a member of IEEE.Jinkang Zhu is a professor of Department of Electronic Engineering & Information Science of University of Science and Technology of China (USTC). Now he is director of Personal Communication Network and Spread Spectrum Lab. of USTC, Chair of the Academic Committee of School of Information Science & Technology of USTC, Vice-Chair of the Academic Committee of USTC.He was Permanent V-President of School of Information Science & Technology of USTC, Chairman of PCN Experts Group of Communication Project of National R&D on High-Technology Programme of China, Member of Information Technology Expert Group of the Chinese Academy of Sciences, Member (Representation of China Mainland) of Technical Forum on Wireless Communications of Asia Pacific Region, Member of Technical Advisory Committee of IEEE VTC99 Fall, Member of Technical Program Committee of IEEE VTC2000, Member of Technical Program Committee of SCI2001.His research area is Wireless and Mobile Communications, CDMA and Spread Spectrum Communications, Signal Process of Communications, and Wireless Networks. He got two awards of Ministry of Science & Technology of China, three awards of Chinese Academy of Science. He published five books and 100 papers, where synchronous CDMA method proposed is used in TD-SCDMA Standard of 3G as basic technology.     

Ku波段宽频带高隔离双极化微带天线阵的设计

设计了适用于Ku波段的宽频带高隔离度双线极化4元微带贴片天线阵.用商业应用软件IE3D对天线电特性进行仿真计算,并制作了实验模型.测量结果与仿真结果吻合良好,两馈电端口驻波小于2的阻抗带宽分别为21.56%与22.58%,隔离度高于32dB,实测增益12.8 dBi.