Соотношения для расчета диаграммы направленности MIMO РЛС при различающихся антеннах приемных и передающих элементов, формирующих ее

Abstract

Introduction: The synthesis of MIMO antenna arrays differs from the synthesis of classical antenna arrays in that the radiation pattern of the former is formed by a virtual aperture. The virtual aperture is formed by the convolution of the coordinates of physical receiving and transmitting elements, which leads to the formation of a large number of virtual elements. Purpose: To obtain relations for calculating the radiation patterns of antenna arrays of MIMO radar with different antennas of receiving and transmitting elements forming it. Results: We obtain an expression for calculating the antenna arrays directivity multiplier of the MIMO radar, which allows us to reduce the number of mathematical operations in comparison with the calculation of the virtual aperture elements arrangement. On the basis of this expression we receive the expression that make it possible to take into account the influence of antenna radiation patterns of receiving and transmitting elements of MIMO antenna array on its directional properties. It allows us to calculate the radiation pattern of the MIMO antenna array of a radar according to the known radiation patterns of antennas of receiving and transmitting elements and the directional multiplier of the virtual aperture. We present a model of a MIMO antenna array with a classical arrangement of elements. Its directivity multiplier is obtained in two ways: the traditional way using the arrangement of virtual aperture elements and by using the expression proposed in the paper. Their difference is identically equal to zero for all angular directions. On the basis of the obtained directivity multiplier we calculate the radiation pattern of MIMO antenna array for the cases when the same and different antennas of receiving and transmitting elements are used. We demonstrate the ways to reduce the level of side lobes of MIMO antenna arrays radiation pattern. Practical relevance: The expression obtained in the paper takes into account the radiation patterns of the receiving and transmitting elements of the MIMO antenna array, which makes it possible to analyze the distortion of the shape of the MIMO radar antenna array pattern during scanning. The computational efficiency of the expression given in the paper and involving 20 receivers and 10 transmitters is 6.3 times.