Limiting the risk to the environment by measuring the characteristics of antennas in the near zone
Authors: Marian Wnuk
Abstract: Measurements in the near zone and the subsequent use of the analytical method and transforming the obtained results to determine the radiation characteristics, which can conveniently replace the conventional far-field range tests. It comes down to the use of closed rooms, such as anechoic chambers, which provide appropriate conditions to carry out measurements and inspections and favourable weather conditions. This is a very cost-effective and time-effective method. The determined characteristics are almost identical in terms of accuracy like those set in the far field. The downside is that some measurements require complex software and their duration is much longer than the real one.The measurement with the probe covers the phase and amplitude of the signal after a predefined scanning area, which is different for each antenna and therefore also the methods, since the method is selected according to the antenna under test. The rectangular planar method was used in the work.After constructing a measuring station and taking measurements, they are transformed by using the Fourier transformation. In the study of a parabolic antenna, these were not complicated operations because planar methods are characterized by simplicity of calculations, in contrast to more difficult cylindrical methods and much more complicated spherical methods.The measurement consists in collecting data on amplitude and phase through a second antenna, which acts as a measuring probe, at specified distance intervals in the azimuthal and elevation directions. Therefore, the used fin antenna is moving on the antenna mast in two planes. The obtained results must be entered into a computer program in order to plot the characteristics.All the considerations, along with the concept of the measurement stand, were based on theoretical foundations, based on knowledge of the types of antennas and their parameters, knowledge of the near zone and its properties, and the behaviour of the signal during measurements.
Keywords: Human Factors in Communication of Design
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