Antenna Array Based on Fabry–Perot Cavity with Mechanoelectrical Beam Steering

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.

Influence of antenna half-power beam width on equipment under test volume in radiation disturbance measurement

Through the study of the latest radiation disturbance measurement standards, the difference between test volume and equipment under test volume was compared and analyzed. Different types of antennas will be used in the radiated disturbance measurement in terms of the different frequency range. Various antennas have kinds of directional characteristics. This article analyzes the influence of antenna half-power beam width on the equipment under test volume, especially on the height, from three frequency ranges. Furthermore, taking the typical horn antenna as the starting point, as well as the formula of volume with antenna half-power beamwidth, the relationship between equipment volume and frequency is calculated. Finally, the influence of antenna half-power beam width on the equipment under test volume is obtained.

Fabrication of Oblique Submicron-Scale Structures Using Synchrotron Hard X-ray Lithography

Oblique submicron-scale structures are used in various aspects of research, such as the directional characteristics of dry adhesives and wettability. Although deposition, etching, and lithography techniques are applied to fabricate oblique submicron-scale structures, these approaches have the problem of the controllability or throughput of the structures. Here, we propose a simple X-ray-lithography method, which can control the oblique angle of submicron-scale structures with areas on the centimeter scale. An X-ray mask was fabricated by gold film deposition on slanted structures. Using this mask, oblique ZEP520A photoresist structures with slopes of 20° and 10° and widths of 510 nm and 345 nm were fabricated by oblique X-ray exposure, and the possibility of polydimethylsiloxane (PDMS) molding was also confirmed. In addition, through double exposure with submicron- and micron-scale X-ray masks, dotted-line patterns were produced as an example of multiscale patterning.

Analysis of the influence of dispersion of metamaterials in a cylindrical Luneberg lens with extended focus

Cylindrical Lunebeg lenses allow azimuthal scanning in a wide sector of angles. The article discusses a cylindrical Luneberg lens with an out-of-focus parallel printed circuit boards made of thin fiberglass (FR-4) with an etched H-shaped metamaterial structure. The distribution of the electric field in the azimuthal plane is shown when a linearly polarized plane wave is incident on the lens surface parallel to the printed circuit boards. The dependence of the focal length on the frequency is shown. Conclusions are drawn about the effect of dispersion on the focal length. To clarify the value of the focal length, thedirectional characteristics of the antenna system are considered when the focal length is changed. Directional characteristics are investigated when the feed is rotated in the azimuthal plane. The results presented in the article are planned to be used to create broadband Luneberg lenses from metamaterials.

Stand for measuring the directional characteristics of antennas of satellite communication systems

The development of network based on satellite communication systems is a promising solution for providing telecommunications services in the Arctic. Therefore, the task of developing and creating earth stations for advanced satellite communication systems that have characteristics significantly higher than their world counterparts is actual. Characteristics of such stations depend on antenna’s systems characteristics that determine the energy characteristics of the communication channel. The aim of this work is a stand developing for measuring directional characteristics of antennas of satellite communication systems based on the spherical scanner (TS8991). Spiral scanning is an alternative measurement method aimed at reducing measurement time with saving necessary accuracy. As a result of this work, the spiral scanning algorithm based on the near-field scanner Rohde & Schwarz TS8991 was implemented. Moreover, the stand for monitoring and configuring the parameters of satellite earth station antennas was built. Block diagram of this stand is presented in article. An antenna with 1,2 m diameter of reflector was tested on the developed stand. The measurement results showed deviations of the measured values from the calculated values, which related by design disadvantages of the antenna. The stand using time was 35 minutes for measurements and conversions to the far field, for an antenna with 1,2 m diameter of reflector.