Phaseless Inversion of Planar Magnetic Near-Field Antenna Measurements

位于卡尔加里的EMSCAN是世界领先的快速平面近场天线开发商， 电磁兼容性测量技术。该项目围绕EMSCAN的RFXpert 该系统提供几乎实时的天线测量。RFXpert收集切向磁场 在AUT的近场区中的平面上的被测天线（AUT）的场。RFXpert系统是 能够收集这些磁场的振幅和相位。从这些测量结果来看， 可以使用标准平面近场到远场变换来计算AUT的图案。 EMSCAN感兴趣的是调查方法来计算辐射模式，从振幅只有（无相位） 磁近场数据这一点很重要，原因有二。首先，这可以大大减少 系统的成本作为无相测量可以简单/准确地通过使用功率 仪表/嵌入式频谱分析仪。第二，这使得EMSCAN能够估计 他们的EMC产品EMXpert仅使用频谱分析仪来测量无相位磁近场数据。 在拟议的项目中，Mojabi团队的目标是实现一种计算机算法， 在AUT前面的平面上收集的磁近场数据，然后返回AUT的辐射图案。 自治区为此，该问题被公式化为最小化的非线性成本泛函上， AUT的等效电流。一旦找到AUT的等效电流， 天线很容易计算。从无相位磁近场数据获得的辐射图将 然后与从幅度和相位磁近场数据获得的辐射图案进行比较， 评估使用无相位数据牺牲了多少精度。

EMSCAN, located in Calgary, is a world-leading developer of fast planar near-field antenna and electromagnetic compatibility measurement techniques. This project revolves around the EMSCAN's RFxpert system that provides almost real-time antenna measurements. The RFxpert collects the tangential magnetic fields of an antenna under test (AUT) on a plane in the near-field zone of the AUT. The RFxpert system is capable of collecting the amplitude and phase of these magnetic fields. From these measurements, the radiation pattern of the AUT can be calculated using the standard planar near-field to far-field transformation. EMSCAN is interested in investigating methods to calculate radiation patterns from amplitude-only (phaseless) magnetic near-field data. This is important for the following two reasons. First, this can significantly reduce the cost of the system as phaseless measurements can be simply/accurately done via the use of a power meter/embedded spectrum analyzer. Second, this enables EMSCAN to estimate electromagnetic emissions in their EMC product, EMxpert, that uses only a spectrum analyzer to measure phaseless magnetic near-field data. In the proposed project, the Mojabi team aims to implement a computer algorithm that takes the phaseless magnetic near-field data collected on a plane in front of the AUT, and then returns the radiation pattern of the AUT. To this end, this problem is formulated as the minimization of a nonlinear cost functional over the equivalent current of the AUT. Once equivalent current of the AUT is found, the radiation pattern of the antenna can be easily calculated. The radiation pattern obtained from phaseless magnetic near-field data will then be compared with the radiation pattern obtained from amplitude and phase magnetic near-field data to evaluate how much accuracy has been sacrificed by using phaseless data.