大型可展开网状天线反枕效应研究进展

SignificanceWith the continuous development of communication satellites, in order to obtain weaker transmission power signals, the satellite antenna needs to further improve the antenna gain and make the antenna aperture larger. As the improvement of communication quality, the working frequency band of satellite antenna also needs to be further improved, so the requirements for the surface accuracy of the reflector are more and more strict. Mesh antenna is the most widely used deployable antenna at present due to the advantages of high storage ratio, low area density and high profile accuracy. Among them, the anti-pillow effect is one of the main sources of the design error of mesh antenna. It will make the antenna deviate from the ideal paraboloid, affect the far-field characteristics of the antenna, and then affect the communication function of the satellite.ProgressThe anti-pillow effect can be expressed by the negative Gauss curvature surface in mathematics. The mechanical properties of the metal mesh can be explained by the thin shell moment free theory in elasticity. Applying a uniform load to the metal mesh can make the main curvature have the same sign, so as to obtain a positive Gauss curvature surface. The inflatable antenna and electrostatic forming antenna are the most ideal uniform load mode. However, the gas inside the inflatable antenna is easy to leak in space. It is too expensive to supplement air source and the self-curing technology is not mature, so it is difficult to achieve the effect of uniform curing in orbit and has not been applied in practice;The realization of uniform load is not ideal. The distributed load can achieve a similar effect. At first, a group of traction cables are added in the rib thickness direction of the single-layer mesh antenna to achieve the equivalent of the distributed load, but the tension provided by this method is limited. Therefore, on the basis of the double-layer mesh, the circumferential cables are arranged in pairs along the front and back sides of the radial ribs to further improve the applied tension. The tension that the circumferential cables can bear is far greater than that of the metal mesh, so fewer traction cables can be used to achieve higher profile accuracy. However, the front cables of the circumferential cable umbrella antenna form small quadrangles, and the anti-pillow effect can not be avoided in each quadrangle. The tension rod antenna connects the diagonal of the quadrangles on this basis.It can be transformed into a triangular cable network, realizing smaller patch division, However, if we want to further increase the profile accuracy, we can only increase the cable mesh density, which will lead to the complexity of the mechanism and the increase of weight.Putting aside the thin shell moment free theory, reducing the bending stiffness of the thin shell is also an idea to solve the anti-pillow effect. The self-resilient antenna obtained by reducing the thickness of the thin shell “t” and the shell membrane antenna by reducing the elastic modulus of the thin shell “E” both eliminate the anti-pillow effect. However, the diameter of the self -resilient antenna is limited by autoclave, and the shell membrane antenna cannot be deployed independently, which requires additional deployment mechanism, and the film surface accuracy is easily affected by the deployment mechanism. The size of these two single thin shell structures is limited by the mold and cannot be further increased. Traditional materials under concentrated load will form negative Gauss surfaces, while negative Poisson's ratio materials under external load will show the opposite characteristics - positive Gauss surfaces. This property has inspired us to solve the anti-pillow effect. The 2D in-plane negative Poisson's ratio materials – re-entrant honeycomb structure, chiral structure, rotating rigid body structure, etc. are investigated. Hexagonal chiral honeycomb materials have in-plane isotropy, and are ideal materials that are expected to be used in deployable reflector antenna. Through the optimization design of traditional hexagonal chiral honeycomb materials, the research group found that the application of negative Poisson's ratio materials can indeed alleviate the anti-pillow effect of mesh antenna, and confirmed the feasibility of negative Poisson's ratio materials in solving the anti-pillow effect of reflector antenna.Conclusions and ProspectsThis paper summarizes the previous research programs to solve the anti-pillow effect, and according to the recent research results of the research group, explores the feasibility of the curved surface bending characteristics of negative Poisson's ratio materials in solving the anti-pillow effect, which can predictably reduce the number of existing mesh antenna adjustment points, optimize the antenna structure, and reduce the antenna quality. In the future, the following aspects need to be studied: (1) design and optimization of negative Poisson's ratio materials (2) macro homogenization Research (3) research on the out of plane stiffness of materials (4) prototype and experiment.