【作者】 王燕；

【导师】 于丁； 郑文宽；

【作者基本信息】 西安电子科技大学 ， 电子与通信工程， 2014， 硕士

【摘要】 近场测量方法具有信息量大、便于室内操作、测量精度高、保密性强、可以全天侯工作等优点,因此这种方法已成为国内外研究目标或天线散射特性的一个重要方法。本文在近场测量理论的基础上,推导了近远场变换理论,并通过计算机仿真,对三维目标和天线的单站近场散射测量方法进行了研究。论文的主要工作如下:首先,研究了近远场变换理论,包括降维算法和三维算法。在电磁理论的基础上,结合特殊函数,推导出了待测目标或天线的散射近场与远场RCS之间的数学关系。其次,应用近远场变换理论三维算法的降维算法研究分析微带天线的远场散射特性。天线散射场由结构模式项散射场和模式项散射场这两部分组成。本文应用单站近场测量方法的降维算法并结合天线散射场的分离理论分别求出了微带天线结构模式项RCS理论值和模式项RCS理论值,并将结构模式项RCS理论值与实际值进行比较。再次,在近远场变换理论三维算法的基础上,通过电磁仿真软件FEKO对单站近场测量方法进行了分析和研究。在仿真测量过程中,用电偶极子作为“自发自收”探头进行近场测量,获得三维目标(圆柱体)的单站散射近场数据,通过近远场变换理论算法公式得到目标的远场单站RCS理论值。同时,通过直接给待测目标加平面波得到目标的远场RCS实际值,最后比较理论值和实际值。结果证实了这种方法对于三维目标的适用性。最后,分析单站近场散射测量方法产生误差的因素,并研究其补偿技术。在分析误差的同时,也证明了采样定理的科学性。更多还原

【Abstract】 Near-field measurement method has many advantages, such as lage information quantity obtained, conveniently measurements indoor, high measurement precision, good confidentiality, all-weather operation. Consequently, this method of measurement plays a very important role in the research field of scattering characteristics about target or antenna at home and abroad. In this paper, the transformation formulas of near-field to far-field are obtained by theoretical analysis so that the relationship between near-field scattering and far-field scattering is built and the monostatic near-field scattering measurement method of the three-dimensional target and antenna is studied by computer simulation. The main work of this paper are as follows:Firstly, the algorithm of near-field to far-field transformation theory is studied, including descending dimensional algorithm and three-dimensional algorithm. Based on electromagnetic theory and combined with special functions, the mathematical relationship between the scattered near-field and the far-field RCS of targets or antennas is built.Secondly, the far-field radiation characteristic of microstrip antenna is studied by using descending dimensional algorithm of near-field to far-field transformation theory. Antenna scattering field always is composed of structural mode scattering field and mode scattering field.is difficult to decide. Both antenna structural mode RCS and mode RCS are calculated by descending dimensional algorithm of near-field to far-field transformation theory and separating theory of antenna scattering And antenna structural mode RCS compared with structural mode RCS calculated directly.Thirdly, based on three-dimensional algorithm of near-field to far-field transformation theory, monostatic near-field scattering measurement method is studied by means of electromagnetic simulation software FEKO. In the simulated measurements, above of all, the electric dispole with the horizontal and vertical polarization is utilized as a "single-transmit single-receive" probe to perform monostatic near-field scattering measurement and obtain monostatic scattered near-field data of the three-dimensional target, the far-field monostatic RCS of the target is obtained by near-field to far-field transformation theory and compared with monostatic RCS simulated directly by FEKO. The calculation results confirm the applicability of the method used in 3-D target.Finally, the factors of producing error in the monostatic near-field scattering measurement method are analysed and compensation technique of error is studied. At the same time, it confirms that sampling theorem is scientific.更多还原