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Introduction. Introduction. Low-profile effective antenna systems (AS) with maintained directional characteristics in a wide sector of scanning angles are required for satellite communication at mobile objects. This article investigates the directional characteristics of a subarray based on a Fabry–Perot cavity and an antenna array with mechanoelectrical beam steering.Aim. To investigate a Fabry–Perot based antenna array with mechanoelectrical beam steering and to estimate its gain and directivity at different scanning angles.Materials and methods. Computer simulations were carried out using the finite element method (FEM), finite difference time domain (FDTD) method and template based post-processing.Results. A subarray based on a Fabry–Perot cavity for an antenna array with mechanoelectrical beam steering was simulated. The efficiency of the subarray comprised at least 65 % in the 11.9…12.5 GHz frequency band. An antenna array based on a Fabry–Perot cavity with mechanoelectrical beam steering was developed and investigated. The calculated characteristics of the developed antenna array agreed well with those obtained experimentally. The gain degradation did not exceed 2.5 dB in the 0…70° scanning angle range. The advantages of using antenna elements based on a Fabry–Perot cavity and developing on their basis mobile satellite antenna systems with wide-angle scanning are noted.Conclusion. The use of a radiator based on a Fabry–Perot cavity and the development on it basis an antenna array with mechanoelectrical beam steering provides an antenna efficiency of no less than 0.5 with a gain degradation of no more than 2.5 dB in the scanning angle range 0…70° from 11.9 to 12.5 GHz.

Introduction. Reflectarrays have a number of design and functional advantages over their closest analogue - reflector antennas (RA). Although microstrip elements are the most preferred reflectarray elements, single-layer microstrip elements do not allow accurate phase control due to the limited phase adjustment range and a high phase slope. The use of multilayer elements significantly complicates the antenna design and increases its cost. The development of a single-layer element that allows more than 360° phase adjustment and a low phase curve slope is urgent.Aim. To develop a single-layer microstrip phase-correcting element with a phase adjustment range of more than 360° and to design a reflectarray on its basis for operation in satellite communication networks.Materials and methods. Numerical studies were carried out using finite element analysis and the finite-difference time-domain method. Radiation patterns were measured using the near-field scanning method in an anechoic chamber.Results. A phase-correcting element based on a single-layer Maltese cross-shaped microstrip element with close to linear dependence of element size on the phase of the reradiated wave and more than 360° phase adjustment range was developed. On the basis of the investigated element, a foldable reflectarray was designed. The reflector consists of four subarrays, which provide its compact folding for transportation. The results of experimental studies confirmed a high efficiency of the reflectarray, the gain of which is 1.5 dB lower than that of an identical overall dimensions RA in a 7 % operating frequency band. The operating frequency band of the reflectarray in 1 dB gain zone was 11 %.Conclusion. On the basis of a Maltese cross microstrip element, it is possible to implement a single-layer reflectarray with a more than 10 % frequency band. The developed prototype showed the possibility of creating highly efficient foldable reflectarrays for operation in satellite communication and television terminals.

This article presents an analysis of an antenna array with combined beam steering. The beam steering by mechanically rotation subarrays and a linear phase delay addition between subarrays is considered. Analytical expressions of directional characteristics of the antenna array with combined beam steering are obtained. The expressions determined geometrical parameters of the antenna array with combined beam steering are obtained. Dependent directional characteristics of the antenna array with combined beam steering versus its geometrical parameters are shown. The advantage of the combined beam steering over the electronic one is presented. The antenna array with combined beam steering has less directivity degradation at the beam tilt over 40° than the antenna array with electronic scanning. The directional characteristics of the antenna array with combined beam steering using obtained expressions are shown.

Design of 600 mm dual Ka/Q-band circularly polarized reflectarray for satellite application is presented. For reflectarray implementation a single-layer microstrip element providing independent control of the reradiating wave phase in Ka and Q-bands was developed. A reflectarray prototype consisting of 24465 elements was manufactured and tested. Measurements of the reflectarray prototype were carried out in an anechoic chamber by the near-field scanning method. The minimum measured gain in ±0.75° angle sector were 35.8 dBi in Ka-band and 36 dBi in Q-band. Measured cross-polarization isolations are below 27 dB and 18.7 dB in Ka and Q-band respectively.

A 0.6 m circularly polarized shaped-beam reflectarray antenna has been designed, manufactured, and tested. Contour of the Russian Federation from a point of 90° eastern longitude on geostationary orbit was used to execute iterative phase synthesis method. For reflectarray realization a single-layer element consisting of a ring with a gap was selected because of their simplicity and the independence of reflected phase from the manufacturing tolerance. Measurements of the reflectarray prototype were carried out in an anechoic chamber by the method of near-field scanning. The minimum measured gain and cross-polarization isolation in the coverage area were 25.6 dBi and 16 dB relatively. Minimum gain of 26.5 dBi and 20 dB cross-polarization isolation are obtained over more than 88% of the coverage area over a frequency range from 20 to 21 GHz.

A subarray for Ku-band wide-angle scanning antenna array based on waveguide continuous transverse stubs (CTS) is presented. The proposed antenna array consists of 2 subarrays, subarray consists of 16 horn radiators. The subarray based on waveguide continuous transverse stubs is fed by a waveguide binary power divider. The CTS subarray for scanning antenna array was calculated and researched. The developed subarray has compact structure, light weight, manufacturability and high efficiency. A beam-scanning range of ± 90° is achieved by mechanically rotating subarrays around its axes at the same angles. The calculated aperture efficiency exceeds 55% in the entire working frequency band. The proposed scanning antenna array with high efficiency can be used for satellite communication terminals and radar systems.

The article presents the investigation results for different types of spatial polarizers for antenna arrays based on continuous transverse stub structures. Three different types of polarizers were simulated, dependence of axial ratio from frequency was determined. An experimental sample of the polarizer that showed the best characteristics was constructed and measured.

This article presents an overview of scanning antenna systems’ models, which were developed on basis of the laboratory “Antennas and microwave devices” of Siberian federal university. An antenna array with beam steering by mechanical dielectric lenses rotating and an antenna array with beam steering by mechanical subarrays rotating are introduced. Calculation and measurement results of the antennas are shown.

The research and development of an antenna array with combined beam steering for Ku-band satellite communications in motion are presented in article. An analytical calculation and electrodynamic simulation of the antenna array with the proposed type of scanning is performed. The possibility of directivity improving of an antenna array with combined beam steering with fixed sub array configuration is studied. A microstrip power divider with a parallel-serial splitting network for antenna array with combined beam steering subarrays was developed. A prototype of the subarray for antenna with combined beam steering was made. An experimental prototype of antenna array with combined beam steering was developed, manufactured and experimentally investigated. A good agreement between measured and calculated characteristics was achieved.

The possibility of implementing a reflectarray for operating at two independent frequency bands on two orthogonal polarizations is considered. Simulating results of the rectangular 2-layer unit cell are presented. Reflectarray prototype has been designed and manufactured. Comparison of simulated and measured results is introduced.

The work presents the study of multilayer structure based on flat dielectric wedges which provides linear phase shift for wide-angle beam steering antennas. The results of numerical simulation are given including the radiation patterns of deflecting structure and of the whole antenna system based on it. Also some methods for improving the performance of the examined system were studied. The presented antenna system showed the ability of mechanoelectrical beam steering within the range of ±45° in elevation plane and 360° in azimuthal plane. The directivity deterioration in elevation plane reached 3 dB relative to zero direction.

The results of simulation and experimental study of the Ku-band antenna array element based on Fabry-Perot cavity (FPC) are presented in the article. The FPC is implemented as double-layered subwavelength FSS acting as partially reflecting surface (PRS). The matching element in form of a dielectric pyramid is presented. The reflection coefficient of fabricated prototype is below −10 dB within the operating frequency band. The gain of the prototype exceeds 18.7 dBi within a range of 12–12.7 GHz. The frequency band at −3 dB from maximum gain level is 9%. The presented array element can be used in high efficient arrays for satellite communications and television.

Meander-line polarizer for a half-wave vibrator is presented. Researched antenna was simulated and prototype was manufactured. The comparison of the theoretical and experimental data for investigated antenna (axial ratio) was produced. Influence of polarizer on half-wave vibrator matching characteristics was researched.

Experimental research results for antenna array with different types of the beam steering are considered. Amplitude and phase distributions over the antenna array aperture are presented at different beam directions for electronic and combined electronic and mechanical beam steering types. Gain difference between two presented beam steering types was more than 6 dB at 60 degrees scanning angle.

In this paper the design of a near-field scanner for antenna measurements is presented. A distinctive feature of the scanner is the absence of probe position sensors. The control circuit is proposed which allows generating the trigger signal for the vector network analyzer during continuous scanning without using information from the probe position sensors. Experimental results demonstrates that the proposed approach allows to perform fast and high quality antenna near-field measurements.

In this paper millimeter-wave reflectarray research, simulation and measurements results are presented. Waveguide elements were used as reflectarray unit cell. Exponential horn was used as illuminator. Low profile reflectarray transforms wavefront like a conventional parabolic reflector. The reflectarray aperture, supporting structure and illuminator were fabricated from aluminum alloy by CNC machine. Measured results show very good agreement with characteristics obtained from the simulations. Manufactured reflectarray provides 50% efficiency in 10% bandwidth.

The paper presents the modeling results of the phase front control structures based on perforated dielectric. One of the structures is a lens antenna with two other being identical structures with a linear phase shift. The beam steering is performed by angular displacement of linear phase shift structures. Presented antenna system provides wide-angle mechanoelectrical beam steering.

The work presents the results of simulation of microstrip reflect arrays. The calculations were made with automated system (CAD system) CST Microwave Studio. The equivalent unit cell waveguide approach was applied to make phase curves calculation for the unit patches. The influence of angular displacement of subarrays of the antenna was considered.