Arrays of electrically small antennas with SINIS detectors for SubTHz astronomy and atmosphere propagation research

An overview of different arrays of electrically small annular antennas of 350 GHz band with integrated superconductor-insulator-normal metal-insulator-superconductor (SINIS) detectors is presented in this paper. Arrays developed for both astronomical observations on the BTA 6 m telescope and measurements there of test sources for investigation of atmospheric turbulence to estimate its influence on the data rate of subTHz telecommunication channels. It is shown both numerically and experimentally that to simulate the electrodynamics of such non-phased antenna arrays it is necessary to investigate the whole array, not a single cell with Floquet ports. The first results of studying of superconducting antennas are also presented in this paper.

A Review of Synthesis Techniques for Phased Antenna Arrays in Wireless Communications and Remote Sensing

Electronically controlled antenna arrays, such as reconfigurable and phased antenna arrays, are essential elements of high-frequency 5G communication hardware. These antenna arrays are aimed at delivering specified communication scenarios and channel characteristics in the mm-wave parts of the 5G spectrum. At the same time, several challenges are associated with the development of such antenna structures, and these challenges mainly originate from their intended mass production, contemporary manufacturing technologies, integration with active RF chains, compact size, dense circuitry, and limitations in postmanufacturing tuning. Consequently, 5G antenna array designers are presented with contradictory design requirements and constraints. Furthermore, these designers need to handle large numbers of designable parameters of the antenna array models, which can be computationally expensive, especially for repetitive and adaptive simulations that are required in design optimization and tuning. Antenna array synthesis, namely, the process of finding positions, orientation, and excitation of the array radiators, is a challenging yet crucial part of antenna array development. This process ensures that the performance requirements of the antenna array are met. Therefore, there is a need for reliable yet fast automated computer-aided design (CAD) and synthesis tools that can support the development of 5G antenna array solutions, from the initial prototyping stage to the final manufacturing tolerance analysis. This paper presents an overview of recent advances in antenna array synthesis from the viewpoint of their applicability to the design of electronically reconfigurable and phased antenna arrays for wireless communications and remote sensing.

Design Calculations of the Limiting Characteristics of Heat Pipes for Cooling Active Phased Antenna Arrays

The article provides an algorithm for calculating the limiting characteristics of heat pipes for cooling active phased antenna arrays at a given saturation temperature. The maximum transmitted power is determined taking into account the limitations of the heat pipes operation by the capillary limit, by boiling (transition to film boiling, boiling limit), by the sonic limit at which the speed of steam reaches the speed of sound (sonic limit), by the entrainment of droplets liquid coolant from the surface of the wick with a counter flow of steam (entertainment limit) and viscous limit, which is realized at low temperatures (viscous limit). It is shown that an increase in the thickness of the wick and its porosity may be necessary to increase the capillary limit of heat pipes, while an increase in the thickness of the wick increases the thermal resistance of the tube and, accordingly, can lead to overheating of the cooled elements. Based on the above algorithm, design calculations for two types of heat pipes have been carried out. The dependences of various limits of the heat pipe on the operating temperature are plotted. Based on the above algorithm, calculations were performed for two types of heat pipes.

Mathematical Modeling of Heat and Mass Transfer in Heat Pipes in a One-Dimensional Formulation when Cooling Active Phased Antenna Arrays

The work proposes test one-dimensional models of heat and mass transfer in heat pipes during cooling of active phased antenna arrays, which can be used in processing the test results of flat heat pipes in order to determine their performance characteristics and identify the parameters required for modeling in a more complex setting (for example, in flat and taking into account the presence of several localized sources of heat supply). To take into account the influence of the heat release power on the equilibrium temperature inside the heat pipe, the model has been added to take into account the dependence of the steam saturation temperature on the pressure, which is realized inside the steam pipeline when the heat pipe is heated. Numerous calculations carried out made it possible to refine the mathematical model. In particular, a significant effect on the temperature distribution along the heat pipe is shown, taking into account the dependence of the steam saturation temperature on the pressure in the parawire. It is shown that the introduction of standard functions for the characteristics of the coolant (water) in the liquid and vapor state, as well as taking into account the capillary pressure on temperature, makes it possible to refine the resulting solution.

STUDY OF PHASED ARRAYS OF SLOTTED WAVEGUIDE ANTENNAS WITH DIELECTRIC FILLING

The article describes the computer simulation of phased antenna arrays consisting of slotted waveguide antennas with air and dielectric filling. It is shown that inser-tion of a thin dielectric layer shifts the operating frequency range of phased anten-na arrays by 1 GHz or more down in frequency while maintaining directional char-acteristics.