MODELING OF THE RADIO DIRECTION FINDING PROCESS BY DIGITAL ANTENNA ARRAYS TAKING INTO ACCOUNT THE EFFECT OF MUTUAL COUPLING OF ANTENNA ELEMENTS

Background. The effect of mutual coupling of antenna elements can have a significant impact on the characteristics of complex, sensitive systems. This effect changes the shape of the directional patterns of antenna elements, changes their active resistance, which complicates the matching of the antenna arrays' impedances. In areas with strict requirements, mutual coupling can have a very significant impact on the results of the system. In particular, they are able to influence the results of digital algorithms for estimating the angular coordinates of radio sources with superresolution. The purpose of this work: to develop a digital model and to simulate the operation of the digital direction finding algorithm. The model should take into account the factor of mutual coupling between the antenna elements. Materials and methods. The work of algorithms for estimating the angular coordinates of radio sources with superresolution as part of antenna arrays consisting of microstrip antenna elements has been studied, taking into account their distorted radiation patterns, as well as the actual scattering matrices of antenna arrays under the action of mutual coupling in the VHF range. Results. The principles of operation of the radio direction finder based on digital algorithms for estimating angular coordinates are described. The effect of mutual coupling of the elements of the antenna array is considered, and its influence on the direction finding results is estimated. A number of models of algorithms for estimating angular coordinates for various types of antenna arrays have been developed, and their comparison has been carried out. The best result is shown by the MUSIC method: the difference in resolution compared to other algorithms was about 10 dB when using microstrip antenna elements. Models of antenna arrays with different types of elements were also developed. The best results were shown by linear arrays with elements – strip antennas with an air dielectric. The difference in the values of deviations and minimally distinguishable angles was 1-2 dB and 8-12 °, respectively. Conclusions. According to the results of the experiments, several antenna arrays with different types of antenna elements were compared. It is established that the best configuration is to use the MUSIC method after processing signals from the outputs of strip antennas with an air dielectric. The obtained data is planned to be used in the future in a full-scale experiment. The obtained