METHOD FOR DETERMINING COMPLEX EXCITATION AMPLITUDES OF PHASED ANTENNA ARRAY CHANNELS BY MEASUREMENTS IN NEAR ZONE

摘要

FIELD: radio engineering.;SUBSTANCE: invention relates to the field of radio engineering of the UHF and EHF bands, namely to phased antenna arrays, and can be used in radio communication systems, radio direction finding and radiolocation. Essence of the method is that before determining the complex amplitudes of excitation of the channels of the phased antenna array, the measuring antenna is moved in a plane parallel to the plane of the phased antenna array. For measuring the complex amplitudes of the excitation of channels of a phased antenna array, a grid of measurements is chosen, the focal points of which are located above the antenna elements of the phased antenna array. Aperture of the phased antenna array is broken into N identical fragments. Reference fragment of the M antenna elements located in the centre of the aperture phased antenna array is selected. Number of antenna elements and the dimensions of the reference fragment, taking into account the distance of the measuring antenna from the uncovered plane of the phased antenna array, should be enclosed in the region of the main beam of the measuring antenna. Shift to the measurements and move sequentially the measuring antenna from one antenna element of the reference fragment to another antenna element, stopping the measuring antenna at the nodal points. Measurements of the complex amplitudes of the excitation channels of this fragment of the phased antenna array are performed using a measuring antenna in the transmission mode. According to the measurement results, the reference fragment of the phased antenna array is calibrated so that all the channels of the reference fragment have the same amplitudes and phases. Then the measuring antenna is installed at the point corresponding to the phase centre of the reference fragment, and the complex coefficients of the channels of the phased antenna array E′_m are measured with a fixed measuring antenna. Coefficients C_m= 1/E′_m are determined, which will be further used as complex normalizing factors for the calibration of the remaining N-1 fragments. Measuring antenna is consistently installed in the centre of each n^th fragment of N-1 and the complex amplitudes of the channel excitation A_{m, n} of this fragment is measured with a fixed measuring antenna. Complex amplitude of the excitation channels E_{n, m} of phased antenna array in the opening fragment is determined, taking into account the directional properties of the measuring antenna, multiplying the complex amplitudes of channel excitation A_{n, m} of this fragment to the corresponding complex normalizing factors C_m= 1/E′_m and obtaining the desired complex amplitude of excitation channels of phased antenna array E_n,_m= A_n,mC_m.;EFFECT: technical result of the invention is the performance gain of the measurements and calibration of the phased antenna array.;1 cl, 5 dwg