This paper presents a multi-physics analysis of a space-based communication satellite dish antenna. Electromagnetic losses due to induced high-frequency surface currents lead to partial, asymmetric heating of the structure, causing stress and deformation. A final electromagnetic analysis is performed on the resulting deformed structure to determine the effect of the deformation on the antenna pattern and overall performance.
Satellites in space often employ dish antennas to direct signals efficiently to a large but limited area of the earth’s surface. For example, a satellite radio transmitter in geostationary orbit may, with an antenna beam width of a tenth of a radian, cover most of the United States. The dish antenna may be illuminated by a small feed horn and connected to the satellite by a metal waveguide or coaxial structure. Due to surface currents on the metals, a fraction of the electromagnetic power is converted to heat. This causes a significant increase in temperature of the structure, since there is no convection in the vacuum of space; heat can escape only through radiation, which is very weak at low temperatures. Higher temperatures, as well as temperature differences between various parts, cause mechanical stress and deformation. Simulation tools from Ansys, specifically HFSS and ANSYS Mechanical software — can comprehensively analyze all these effects. Furthermore, the resulting deformed structure is brought back into the electromagnetic simulation tool, HFSS, to determine how the deformations affect the antenna pattern.
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Courtesy of EE Times India