Yu.N. Gaichyk1, N.V. Tamp2, V.A. Romakhin3, A.A. Omelshin4

1–4 Military University of Radio Electronics (Cherepovets, Russia)

In the middle wave range, due to the design features, asymmetric vibrators are represented quite widely, in particular, a quarter-wave asymmetric vibrator with an omnidirectional (circular) radiation pattern in the horizontal plane, and in the vertical – within the angles of ± 30 ° relative to the horizontal plane. To calculate the characteristics of asymmetric vibrators, the method of mirror images is used, while the vibrator is understood to be located above an ideally conducting infinite plane. However, in practice, they are placed on buildings with finite dimensions of mobile objects. Currently, the influence of the shape and size of the screen (the attachment point on the body of the object) on the radiation of a quarter-wave asymmetric vibrator has been studied in detail in a number of works, while the effect of the placement of third-party objects on the radiation pattern has not been sufficiently studied. In connection with the conducted research in this area. In the Ansys HFSS software, a computer simulation of the operation of a quarter–wave asymmetric vibrator without third-party objects and with three layouts having different geometric dimensions, namely: layout 1 (length – 3 m and diameter – 0.13 m), layout 2 (length – 5 m and diameter – 0.3 m), layout 3 (length – 7 m and diameter – 0.7 m). The results of computer modeling have shown that objects make changes to the shape and structure of the radiation pattern, in particular, the side lobes have a rugged character and dips, a quarter-wave asymmetric vibrator located on a screen of finite dimensions. The above made it possible to put forward a hypothesis about the statistical significance of the differences in the radiational patterns of a quarter-wave asymmetric vibrator with different geometric dimensions of third-party objects placed within the screen. To work with the results of computer modeling and proof of the hypothesis, preliminary processing of the obtained data was carried out. To this end, a program was implemented in the MATLAB software that allowed converting the results of observations into n-samples for further research, including using statistical methods. At the initial stage, using the Shapiro-Wilk test, it was found that the data in the n samples are distributed differently from the normal law, therefore, nonparametric criteria must be applied. Two decision-making criteria were chosen: Friedman and Man-Whitney, according to which calculations were carried out in the Jupiter software in Python. As a result, for all n samples, the level of statistical significance (p-level) is less than the value, respectively, the differences between the samples are statistically significant. The influence of third-party objects on the shape and structure of the radiation pattern of a quarter-wave asymmetric vibrator is confirmed by computer modeling in the Ansys HFSS software, further processing in the MATLAB program, while the observation results have statistically significant differences. The above suggests that the actual direction of further research is to study the possibility of fixing by technical means of radio monitoring the differences in the radiation patterns of a quarter-wave asymmetric vibrator, depending on the third-party object placed within the screen.

Gaichyk Yu.N., Tamp N.V., Romakhin V.A., Omelshin A.A. Evaluation of the influence of third-party objects on the radiation pattern of a quarter-wave asymmetric vibrator. Electromagnetic waves and electronic systems. 2023. V. 28. № 3. P. 11−17. DOI: https://doi.org/ 10.18127/j15604128-202303-02 (in Russian)

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