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• ANALYSIS OF THE CAUSES OF ERRORS IN THE AMPLITUDE-PHASE DISTRIBUTION OF LINEAR PHASED ANTENNA ARRAYS AND METHODS FOR THEIR REDUCTION

  S.S. Bybin , N.P. Dunaev , S.V. Kuzmin , А.N. Morozov

  2026-02-27

  Abstract ▼

  To use a phased array antenna in the beamforming mode, it is necessary to establish a certain amplitude-phase distribution at the inputs of the emitting elements. Amplitude and phase errors distort the radiation pattern. The paper analyzes the sources of errors in the amplitude-phase distribution of phased antenna arrays, including parasitic phase shifts, nonlinear amplification paths, temperature instability and mutual electromagnetic coupling between the elements. Three methods of calibration and adjustment of phased antenna arrays are described, based on direct measurements of the transmission coefficients in the near zone and the subsequent calculation of the impact vector using inverse and pseudo-inverse matrices of mutual connections, which provides a systematic approach to error elimination. To obtain the initial values, each channel was pre-calibrated along a closed path using a vector network analyzer. Technique 1 implements correction for a set of points in space and one set of states of each channel. To increase the stability of the solution, method 2 uses the regularization of the elements of the matrix of interconnections based on an additional set of measured states of each channel. Method 3 makes it possible to construct a mathematical model of a specific implementation of a phased array antenna based on measurements with a fixed channel state, which ensures the formation of an arbitrary amplitude-phase state without repeated measurements. An experimental setup of an eight-element equidistant linear phased array antenna was carried out. The lattice attenuator/phase shifter modules are based on the PE44820 phase shifter and PE4302 attenuator debugging boards and are controlled by a microcontroller to automatically change phases and amplitudes. The measurements were carried out automatically on a near-field stand in an anechoic shielded chamber using a vector network analyzer. Calibration results are presented, matrices of mutual relationships are constructed and radiation patterns are formed, confirming the operability of the proposed approaches. Since the experimental array is low-element, the results of applying the considered techniques are compared with the results of tuning in the far zone performed using an evolutionary algorithm.

• BROADBAND DOU BASED ON ROTHMAN'S PRINTED LENS FOR MULTIBEAM ANTENNA ARRAYS

  D.Е. Gubarev, Y.V. Yukhanov

  154-164

  2025-08-01

  Abstract ▼

  The most well-known beamforming device (DOU) (for linear and flat MAR) is the Rothman
  lens, which is of great interest because it allows you to form a fan of MAR rays in a wide spatial
  sector of angles (wide-angle scanning), has a fairly high efficiency and MAR with a lens Rothman
  has a low level of side lobes. Another advantage of the MAR with a Rothman lens is the weak dependence
  of the position of the rays in space on frequency, in contrast to the MAR with a Butler
  matrix DOE, in which, at a high efficiency (theoretically 100%), the position of the rays depends
  on the frequency. However, the previously developed analogs of the Rothman lens are large and
  require additional components in the design, which affects the transmission coefficient of the lens
  in the operating frequency range from 2 GHz to 20 GHz and the consistency of the device with
  other components of the transceiver equipment. It follows that the study and modernization of lens
  structures in relation to multibeam antenna arrays (MAR) is a topical topic for research. The purpose
  of the work is to propose a method for calculating the Rotman lens, modernize the lens design,
  make a lens model and conduct an experimental study of the lens in order to obtain constructive
  methods for optimizing the characteristics of the Rotman lenses for use in MAP in the frequency
  range from 2 GHz to 20 GHz. In the results of the article, the dimensions of the lens, the
  mass of the lens, the transmission coefficient, and the simplicity of the design are estimated in comparison with the previously developed analogues. A technique for calculating the geometry of
  a Rotman lens is proposed, the SWR of a printed Rotman lens is experimentally studied on a vector
  network analyzer, constructive methods are obtained for optimizing the characteristics of Rotman
  lenses for use in multibeam antenna arrays. A model of a broadband Rotman lens in microstrip
  design with a maximum SWR of 1.3 (S21) in the operating frequency range from 2 to 20 GHz was
  made, the lens size was 150x100, and the lens weight was 0.4 kg. According to these parameters,
  the Rothman lens surpasses the analogues developed earlier