Evaluating near-field radiation patterns of commercial antennas

Abstract

A source reconstruction technique from the measured near fields is proposed to obtain a set of equivalent currents that will characterize the forward and backward radiation patterns of an antenna. Once the equivalent sources are determined, the electromagnetic field at any aspect angle and distance from the antenna can be calculated. In this paper, the method is applied to the evaluation of the radiation from commercial antennas at any observation point. The electric field patterns of a DCS base station antenna at 1800 MHz and a horn antenna at 2500 MHz have been calculated and plotted at several distances from the antenna. This method can be used in characterizing the "reference volumes" or exclusion zones for transmitting antennas dealing with the maximum levels of electromagnetic radiation safe for human exposure, as stated in many national and international regulations.Index Terms-Antenna measurement, equivalent magnetic currents, human exposure, near-field pattern, near-field to far-field transformation, non-ionizing EM fields.

Fast Antenna Characterization Using the Sources Reconstruction Method on Graphics Processors

“…The resulting system of equations is underdetermined. However, as indicated in previous works [5,14,21,24], the SRM seeks a least-mean-square solution, that is, the minimum energy solution. The issue of solution uniqueness of the inverse problem for antenna characterization has been widely discussed in [13,24,25], as well as the different ways of Equivalence Principle application depending whether the zero internal field condition is enforced or not.…”

“…The SRM does not impose any geometrical restriction to the acquisition and reconstruction domains [5,14,21,24] which enlarges its scope of application beyond antenna characterization and diagnostics. For instance, in [14] the SRM is used to obtain the exclusion zones for human exposure of transmitting antennas and in [21] the equivalent currents are computed on a radome to improve its design.…”

“…For instance, in [14] the SRM is used to obtain the exclusion zones for human exposure of transmitting antennas and in [21] the equivalent currents are computed on a radome to improve its design.…”

A decoupled source current reconstruction method for noisy and reactive near-field to far-field transformation

“…Measuring the nearfields of the antenna under test (AUT) and reconstructing the far-field (FF) radiation is one of the most widely used advanced measurement techniques. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Near-field (NF) measurements have dramatically reduced the dimensions of test facilities and test costs and increased measurement speeds.…”

“…However, up to the authors' knowledge, most of the available NF to FF transformation method are placed in the region that the reactive radiations are negligible and the effects of evanescent modes on the field transformation procedure have not already studied. [1][2][3][4][5][6][7][8] For NF to FF transformation, two main methods have already been reported over the past years. The oldest method which has been used widely is the modal techniques.…”