Deployable structure of curved profile for space antennas

In the past, deployable structural mechanisms made from pantographic elemen ts of straight struts could form only certain shapes because of restriction s imposed by geometric compatibility conditions, which prohibit the concept s from being used in applications such as antenna reflectors where nodes of the structure usually lie on a parabolic surface. This paper presents a ge neric solution for construction of deployable structures in any shape of ro tational symmetry. The structures have an internal degree of mobility. The key difference between this new concept and the others is the introduction of a novel type of intermediate element consisting of two ordinary pantogra phic elements, which provides far greater freedom in designing the shape of the structure while structural mobility is intact. Furthermore, the interm ediate element can be added into any existing deployable pantographic struc ture to increase the overall stiffness while retaining its ability of deplo yment. This paper gives full geometric proof, together with a design for jo ints. The concept can be extended into other structural forms. This type of structure can be used as the backbone of deployable antennas or shelters i n space.