| dc.description.abstract | This paper primarily explores the deployable mesh reflector antennas with metasurfaces in satellite antenna systems. The objective is to devise a system that can maintain high gain and high directivity throughout the operating bandwidth, thereby enhancing its suitability for space missions. The research is centered around three key components: the feed antenna system, the deployable mesh reflector antenna system, and the metasurfaces to enhance the gain of the deployable mesh reflector antenna.
The feed antenna system design is mainly made of aluminum. This structure comprises two main components: a horn antenna and an orthomode transducer. At the central frequency of 9.5 GHz, the measured gains for the vertical polarization port and horizontal polarization port are 9.54 dBi and 9.58 dBi, respectively. Additionally, the polarization isolation exceeds 30 dBi.
In the context of the deployable mesh reflector antenna system, this paper presents the design of a reflector antenna featuring a focal length of 1.5 meters and a diameter of 3.8 meters, the F/D ratio is 0.39. This paper examines the disparities between the ideal parabolic reflector antenna and practical engineering manufacturing constraints. It conducts a simulation-based comparative analysis of various configurations, varying the number of parabolic reflector ribs and the dimensions of the circular platform. The simulations include cases with 24, 30, and 36 ribs, along with circular platform sizes of 1.1 meters and 1.4 meters. The aim is to ensure that the satellite antenna system maintains mechanical and structural stability while delivering high-gain, low side lobe level performance within the given payload volume and weight limitations.The ideal parabolic reflector antenna designed in this paper is operated at a center frequency of 9.5 GHz, the gain for the vertical polarization port is 49.52 dBi and the gain for the horizontal polarization port is 49.55 dBi. After various mechanical stability evaluations, 36 ribs and a 1.1-meter circular platform were selected to balance the trade-off between mechanical structure and electrical properties, but this also resulted in a decrease in gain.
This paper found that the size of the circular platform has the most obvious impact on the gain in the deployable mesh reflector antenna system. Therefore, this paper proposes a metasurfaces antenna to replace the circular platform. Through metasurfaces of different sizes, The antenna unit generates different required reflection compensation phases. The designed metasurfaces antenna unit reflection compensation phase covers 0~360 degrees and has a good reflection compensation phase gradient slope. In order to verify the designed metasurfaces antenna unit, this paper designed a metasurfaces antenna with a focal length of 190mm and a diameter of 480mm. At the center frequency of 9.5GHz, the gain excited by the vertical polarization port is 29.95dBi, and the gain excited by the horizontal polarization port is 30.05dBi. The gains of simulation and measurement are almost consistent. In comparison, when the metasurfaces antenna was replaced with a planar structure with only a circular platform, the gain was only 11.45dBi. At the same time, this paper also simulates an ideal parabolic reflector antenna with the same focal length to diameter ratio. Although the gain of the metasurfaces antenna is still 1.4dBi lower than that of the ideal parabolic reflector antenna, the metasurfaces antenna has greatly made up for the loss caused by the circular platform.
Finally, this paper combines the designed metasurfaces antenna unit with a deployable mesh reflector antenna containing 36 ribs and a 1.1-meter circular platform. The simulation results show that the designed metasurfaces antenna improves the performance of the deployable mesh reflector antenna. The gain has a great effect and improves the impact of the circular platform on the deployable mesh reflector antenna. | en_US |