Design of a Deployable Offset Mesh Reflector Antenna Utilizing a Deployable Ring Truss Structure

초록

In this paper, we propose the optimal shape of a 1.5 m offset mesh reflector antenna using a deployable ring truss structure. The proposed antenna consists of a deployable mesh reflector and a feed antenna. The mesh reflectors are typically expanded by tension to maintain their parabolic structure; thus, shape deformation cannot be avoided compared to an ideal parabolic shape. To analyze the performance degradation caused by multiple flat subdivisions of the mesh, the bore-sight gain and main lobe direction are evaluated depending on the number of subdivisions. Additionally, their variations in accordance with the feed antenna's position and direction are analyzed in relation to the asymmetric structure of the offset reflector. To verify the performance of the mesh reflector antenna, a steel use stainless (SUS) mesh reflector (Prototype I), molybdenum mesh reflector (Prototype II), and the feed antenna are fabricated and measured in both near-field and far-field conditions. The measured bore-sight gains of Prototype I are 21.8 dBi (2 GHz), 23.9 dBi (3 GHz), 25.8 dBi (4 GHz), which agree well with the simulation results of 21.0 dBi, 24.1 dBi, and 26.4 dBi, respectively. In the case of Prototype II, the average bore-sight gain is approximately 3.7 dB lower than the simulation results. This is attributed to the displacement of the feed antenna caused by the gravitational sagging of the boom. In contrast to Prototype I, Prototype II mounts the feed antenna at the tip of the boom, making it more susceptible to deformation. To address this issue, a gravity-compensated (0G) measurement setup is planned for future studies.

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