A large antenna surface is needed to obtain high-precision earth observation images and large-bandwidth space-based communications. Due to the limited volume of rocket fairings, the antenna should be foldable and deployable, i.e., compactly folded for transport and deployed in orbit. Depending on whether the components are rigid or flexible, deployable antennas can be divided into rigid panel antennas and flexible antennas. Rigid panel antennas are made of high-stiffness panels that can easily ensure surface accuracy. According to the deployed shapes, there are two types of antennas: those with curved surfaces and those with flat surfaces. The two most common antennas that have a curved surface are the parabolic antenna and the parabolic cylindrical antenna; the latter has a simple geometric shape and is easy to fold and expand, which has attracted the attention of researchers. However, the current parabolic cylindrical antennas still have some problems, such as a low folding ratio and joints remaining on the antenna surface.

        To solve these problems, the team of Prof. Yan Chen from the school of mechanical engineering at Tianjin University, in cooperation with Dr. Ming Li of Aerospace System Engineering Shanghai, designed a novel thick-panel origami-based parabolic cylindrical antenna based on Miura-ori. The antenna is one-DOF and has a high deployed/folded ratio, along with a continuous and smooth reflector, demonstrating great engineering potential.

        Firstly, the researchers constructed two five-vertex thick-panel Miura-ori based on thick-panel origami theory and assembled them in a mirror-symmetric way using specific connectors designed from spherical 4R linkages and Bennett linkages to construct an assembly of two flat surfaces with a dihedral angle. Then, by removing partial material from the surfaces of the structure, a parabolic cylinder was formed, as shown in Fig. 1.

Fig. 1. Schematic diagram of the parabolic cylinder construction process. (a) The mirror-symmetric assembly of two identical Miura-ori thick panel patterns; (b) the removal of material from the front of the assembly to form a parabolic cylinder; (c) the parabolic cylinder structure based on two Miura-ori thick panel patterns; (d) the schematic diagram of the parabola projected on the cross section.

        After removing partial material, some joints remain on the surface of the structure to satisfy the geometric conditions of mobility, as shown in Fig. 2a, which are not conducive to the antenna. To remove the joints and maintain kinematic equivalence, two joint-removing techniques are proposed. The first technique replaces Bennett-linkage thick-panel origami with Bricard-linkage thick-panel origami to remove partial joints based on the kinematic equivalence between them. The second technique removes the remaining joints directly and proves the one-DOF property of the mechanism assembly after joint removal to ensure rationality. Then, the deployed/folded ratio influencing factors are fully studied, finding that a small panel thickness and a large origami pattern sector angle are necessary to obtain a high deployed/folded ratio. Finally, a prototype of the deployable structure is manufactured to verify and demonstrate its excellent performance. The simulation model and the physical prototype are shown in Figs. 3 and 4, respectively.

Fig. 2. Joints on the (a) front and (b) back of the deployable structure.

Fig. 3. The deployable structure after joint removal. (a) Front view; (b) back view.

Fig. 4. (a)-(f) Folding sequences of a deployable parabolic cylinder prototype.

        This work was published in Mechanism and Machine Theory. In this study, a novel deployable parabolic cylindrical antenna with great folding efficiency based on thick-panel Miura-ori was proposed. Two joint-removing techniques were constructed to obtain the continuous and smooth reflector and maintain the one-DOF property. As a new scheme of deployable antennas with a large deployed area, this antenna has a good application prospect in engineering.

Zhang Y#, Li M#, Chen Y, Peng R, Zhang X*. Thick-panel origami-based parabolic cylindrical antenna. Mechanism and Machine Theory, 2023, 182: 105233.
(https://doi.org/10.1016/j.mechmachtheory.2023.105233)