Methodology for selecting the method of mirror antenna protection in SHF-EHF bands from meteorological precipitations
Authors: Shaposhnikova A. M. 
Published: October 2024

Exhaustion of SHF band capabilities in the organization of space communication channels necessitated the transition to the lower part of the EHF band (up to 95 GHz). At the transition stage space channel antennas function in the dual frequency range. This leads to the fact that the methods of protection of ground sector mirror antennas from the impact of meteorological factors should take into account the peculiarities of propagation of millimeter-wave radio waves in the layer of precipitation that can occur in the antenna reflector. For a scientifically justified choice of the method of protection there should be a methodology that allows taking into account both electrodynamic peculiarities of propagation of radio waves of SHF and EHF ranges, and meteorological peculiarities of the antenna location. The latter determines the relevance of the proposed research topic. The objective of the article is ensuring minimum power losses and fulfillment of the rain unavailability index of the mirror antenna of the SHF-EHF wavelength bands of space communication channels by means of a reasonable choice of the method of protection against the impact of meteorological precipitation characteristic of the antenna location. It has been shown that the functioning of mirror antennas of satellite ground stations in the dual frequency range of SHF-EHF makes it obligatory to take into account the peculiarities of propagation of millimeter-wave range waves in water formations when choosing methods of protection from the effects of meteorological precipitation. The most important of these features is the increase in energy losses of millimeter-wave radio waves in the layer of water formations, the thickness of which becomes comparable to the wavelength. In addition, the methods of antenna protection should also take into account the peculiarities of digital communication lines, in particular, the fulfillment of an additional requirement (rain readiness index), assuming the restoration of the operating state of the reflector within a time of up to 10 s. The above features allowed us to formulate a criterion for a scientifically justified choice of the method of protection of the antenna of dual frequency range. The developed methodology for selecting the method of protection of the mirror antenna of the dual wavelength range is based on the theory of meteorological electromagnetism. This allows not only modeling the radio wave energy losses in the layer of precipitation taking into account strict electrodynamic models, but also assigning the parameters of the layer of water formations (thickness, type of precipitation) taking into account the climatic features of the location of the mirror antenna. Thus, the developed method provides the following algorithm for selecting the method of protection. By geographic coordinates the climatic region of antenna location is determined. For abnormal climatic regions (temperature from ‑60° to +50°, wind force up to 70 m/s, snow load up to 250 kg/m3) the application of radio transparent shelter (radome) is an alternative protection method. For other climatic regions the choice of the method of protection of the mirror antenna implies three steps: 1) estimation of energy losses in the precipitation layer on the antenna reflector at refusal of protection methods (maximum possible losses); 2) calculation of the complex criterion; 3) selection from the proposed table of the method that most fully satisfies the criterion and is the most effective for the climatic region of antenna placement. The proposed methodology allows on a scientific basis to choose the method of protection of mirror antennas of the dual frequency SHF-EHF range taking into account the meteorological features of the climatic region of its location.