Synthetic aperture radar (SAR) has been widely applied in marine observation and in the disaster and environmental detection of earth observation. Planar deployable antenna, which is one of the indispensable components of SAR, has a flat developed working surface and a coordinated back frame with good stiffness. However, most planar deployable antennas in orbit lack modular design methods to meet the folding ratio requirements. With the continuous improvement of earth observation range and accuracy, the requirement of large-scale two-dimensional deployable antennas is proposed. The current research on planar deployable antennas is mostly focused on one-dimensional direction, and the research on two-dimensional deployable antennas is less.
        To solve this problem, Professor Chen Yan of the School of Mechanical Engineering of Tianjin University cooperated with the Shanghai Institute of Aerospace Systems Engineering to carry out a two-dimensional planar deployable antenna based on a double-layer Miura-ori pattern. The sub-panels of the antenna all have rectangular working surfaces, and there is a back frame to improve the stiffness of the overall structure.
        First, a Miura-ori unit with a rectangular working surface was constructed by means of a double-layer structure (Fig. 1a). The surface structure design was carried out on Miura-ori with four vertices by hinge-protruding, hinge-removing, and hinge-replacing (Fig. 1b-d), and the planar deployable antenna with a flat developed surface was formed.

Fig. 1. Thick-panel origami with rectangular working facets: (a) construction process of Miura-ori thick-panel unit with rectangular profiles; (b) a four-vertex thick-panel origami with rectangular working facets; (c) protrude partial hinges; (d) thick-panel origami after removing partial hinges.

        The thick panel form of double Miura-ori was constructed by converting the rotating pairs between the upper and lower layers into cylindrical pairs(Fig. 2). Combined with the planar mechanism (Fig. 3), a back frame of four-vertex Miura thick-panel origami was constructed, and the principle prototype was manufactured to verify the single-degree of freedom coordinated motion characteristics of the deployable array antenna and its back frame(Fig. 4).

Fig. 2. Thick-panel form of origami tube: (a) origami tube and its corresponding vertices; (b) the thick-panel form.

Fig. 3. The deployable structure with back frame: (a) double-layer thick-panel origami; (b) the y-directional view of (a); (c) the mechanism of diagram of panels in rows 1 and 3; (d) the mechanism of diagram of panels in row 2.

Fig. 4. The prototype of the deployable structure with compatible back frame: (a) the deployable structure with modified back frame; (b) the deployable structure’s deployed configuration with the flat rectangular working surface; (c–e) the folding sequence of the prototype about the deployable structure with back frame.

        This work was published in Mechanics Research Communications. In this study, the rectangular and flat surface of the deployable antenna structure is realized by hinge-removing, hinge-protruding, and hinge-replacing based on Miura-ori. The compatible back frame is designed by combining the double-layer Miura-ori and planar mechanism. The research provides a new idea for designing a two-dimensional deployable structure for a planar antenna based on origami.

C. Zhao#, M. Li#, X. Zhou, T. Liu, J. Xing, Y. Chen, X. Zhang*, Deployable structure based on double-layer miura-ori pattern, Mech. Res. Commun. (2023) 104152.
(https://doi.org/10.1016/j.mechrescom.2023.104152)