近场测量技术是现代天线测试的重要方法之一。其中，柱面测量技术广泛用于测试宽波束的中等增益天线，是复杂度介于平面测量和球面测量技术之间的方法。本文的研究内容集中在柱面近远场变换技术和探头修正算法上，同时为了抑制测量过程中多径效应的影响，本文详细讨论了模式滤波技术（C-MARS）。为了解决常用的矩形开口波导天线带宽不足且尺寸较大的问题，本文还设计了一款超宽带Vivaldi探头。

文章详细介绍了柱面近场测量的原理。首先根据麦克斯韦方程组求解亥姆霍兹方程得到柱面波的展开式。被测天线的远场可以表示为两组相互正交的矢量波函数在某一场点上的叠加，其叠加系数被称为模式系数，这就是柱面近远场变换的模式展开法的基本思路。接下来本文详细推导了从柱面采样得到的被测天线的近场幅度以及相位数据计算模式系数的数学表达式。为了减少叠加求解无限远场的计算量，本文对模式展开公式在无限远距离下做了极限运算，并给出了远场任意一点处电场值的计算公式。为了引入柱面近远场变换的探头修正。本文从被测天线和探头之间的传输矩阵出发，推导了模式展开系数与近场数据以及探头远场特性之间的数学关系，给出了考虑探头修正的模式系数计算式。由于探头修正需要得到探头自身的远场特性，本文分别对矩形开口波导的方向图进行了理论计算和建模仿真，然后对比远场结果，用以验证将用于探头修正计算的探头远场是否可信。此后，本文在微波暗室内进行了柱面近场实机测试，分别计算出被测天线在引入探头补偿前后的远场方向图，结果表明探头修正算法对近远场外推的精度有显著提升。

为了解决近场测量环境带来的多径效应的影响，本文详细讨论了基于模式系数的滤波方法，消除了反射源杂波对近场外推结果的干扰。同时本文讨论了模式滤波的采样原则，并最后通过实验检验了滤波技术的效果。经过滤波的远场方向图和没有放置反射源的情况下的远场方向图基本一致。

近场测量一般使用矩形开口波导天线作为接收探头。为了满足矩形波导的传输条件，工作在稍低频段的矩形开口波导通常设计的尺寸较大，同时还必须配备同轴波导转换器用来和系统的接口适配，这大大增加了探头整体的尺寸和重量使其难以部署。本文设计并加工了一款3-8GHz超宽带Vivaldi天线用作探头。该天线使用微带转槽线馈电方式，并且通过分别在槽线和微带线的末端增加圆形谐振腔和扇形枝节拓展工作带宽，仿真结果在3-8GHz频段内具有8-14dB之间的增益，S11始终小于-10dB，-3dB波束宽度均大于30°。实测结果与仿真大致相同，符合近场测量需求。

Near-field measurement technology is one of the important methods for modern antenna testing. Among them, cylindrical measurement technology is widely used to test medium gain antennas with wide beams, which is a good choice between planar measurement and spherical measurement. This paper focuses on the cylindrical near-far field transformation technology and probe correction algorithm, and also discusses the mode filtering technology (C-MARS) to suppress the effects of multipath effects in the measurement process. In order to solve the problem that the commonly used rectangular open waveguide antenna has insufficient bandwidth and large size, an ultra-wideband Vivaldi probe is designed.

The principle of cylindrical near-field measurement is described in detail. The expansion of cylindrical wave is obtained by solving the Helmholtz equation based on the Maxwell equation system. The far field of the measured antenna can be represented as the overlap of two sets of orthogonal vector wave functions at a certain point. The overlap coefficient is called the mode factor, which is the basic idea of the mode expansion method for cylindrical near-far field transformation. Next, the mathematical expressions of the near-field amplitude and phase data calculation mode coefficients of the measured antenna sampled from the cylindrical surface are deduced in detail. In order to reduce the amount of calculation for solving infinite field by overlay, this paper makes a limit operation for the mode expansion formula at infinite distance, and gives the formula for calculating the field value at any point in the far field. Probe correction for introducing cylindrical near-far field transformation. From the transmission matrix between the measured antenna and the probe, the mathematical relationship between the mode expansion factor and the near-field data and the far-field characteristics of the probe is deduced, and the formula for calculating the mode factor considering the correction of the probe is given. Because the far-field characteristics of the probe itself need to be obtained for the probe correction, the theoretical calculation and Simulation of the rectangular open waveguide pattern are made respectively, and then the far-field results are compared to verify the reliability of the probe far-field used for the probe correction calculation. Finally, this paper conducts cylindrical near-field measurements in a microwave anechoic chamber, and calculates the far-field pattern of the measured antenna before and after introducing the probe compensation. The results show that the probe correction algorithm can significantly improve the accuracy of near-far field extrapolation.

In order to solve the multipath effect caused by the near-field measurement environment, the principle of the mode factor filter method is discussed in detail, which eliminates the interference of the reflected source clutter on the near-field extrapolation results. At the same time, the sampling principle of the mode filter is discussed, and the effect of the filter technology is verified through experiments. The filtered far-field pattern is basically the same as the far-field pattern without a reflector.

Rectangular open waveguide antennas are commonly used as receiving probes in near-field measurements. In order to meet the transmission conditions of rectangular waveguides, rectangular open waveguides operating at slightly lower frequencies are usually designed to be larger in size, and coaxial waveguide converters must be equipped to fit the interface of the system, which greatly increases the overall size and weight of the probe and makes it difficult to deploy. A 3-8GHz ultra-wideband Vivaldi antenna is designed and simulated as a probe. The antenna uses a microstrip slot-line feeding method, and expands its operating bandwidth by adding circular cavity and sector branch at the end of the slot and microstrip line respectively. The simulation results show that the gain is between 8-14dB in the 3-8GHz band, S11 is always less than -10dB, and -3dB beam width is greater than 30 degrees, which meets the requirements of near-field measurement.