大型可展开网状天线反枕效应研究进展OA

Significance With the continuous development of communication satellites,antennas are required to achieve higher gain and larger apertures in order to receive weaker transmitted signals.With the improvement of communication quality,the operating frequency band of satellite antennas also needs to be further increased,leading to increasingly stringent requirements for reflector surface accuracy.Mesh antennas are currently the most widely used type of deployable antenna due to their advantages of a high stowage ratio,low area density,and high profile accuracy.Among these,the pillow effect is one of the main sources of design error in mesh antennas.It causes the antenna surface to deviate from the ideal parabo-loid,affects the far-field characteristics of the antenna,and consequently degrades the communication performance of the satellite. Progress The pillow effect can be described mathematically as a surface with negative Gaussian curvature.The mechanical behavior of the metal mesh can be explained using the moment-free thin-shell theory in elasticity.Applying a uniform load to the metal mesh can make the principal curvatures have the same sign,thereby forming a surface with positive Gaussian curvature.Inflatable antennas and electrostatic forming antennas represent the most ideal uniform loading modes.However,the gas inside inflatable antennas is prone to leakage in space.Supplying an air source is expensive,and self-curing technology is not yet mature,making it difficult to achieve uniform curing in orbit;therefore,such systems have not been widely applied in practice.As achieving an ideal uniform load is challenging,distributed loading can provide a similar effect.Initially,a group of traction cables is added along the rib thickness direction of single-layer mesh antennas to achieve an equivalent distributed load;how-ever,the tension provided by this method is limited.Therefore,based on double-layer mesh structures,circumferential cables are arranged in pairs along the front and back sides of the radial ribs to further increase the applied tension.The tension capacity of the circumferential cables is much higher than that of the metal mesh,allowing fewer traction cables to achieve higher profile accuracy.However,the front cables of circum-ferential cable umbrella antennas form small quadrilaterals,and the pillow effect cannot be avoided within each quadrilateral.The tension rod an-tenna connects the diagonals of these quadrilaterals,transforming the structure into a triangular cable network and enabling finer surface segmen-tation.However,further improvements in profile accuracy require increased cable mesh density,which leads to greater structural complexity and higher weight.Beyond the moment-free thin-shell theory,reducing the bending stiffness of the shell is another approach to mitigating the pillow effect.Self-resilient antennas,achieved by reducing the shell thickness t,and membrane antennas,achieved by reducing the elastic modulus E,can both eliminate the pillow effect.However,the diameter of self-resilient antennas is limited by autoclave manufacturing constraints,and mem-brane antennas cannot be deployed independently,requiring additional deployment mechanisms;moreover,their surface accuracy is easily af-fected by these mechanisms.The size of these single-shell structures is also limited by mold constraints and cannot be further increased.Tradi-tional materials subjected to concentrated loads tend to form surfaces with negative Gaussian curvature,whereas materials with a negative Pois-son's ratio exhibit the opposite behavior,forming surfaces with positive Gaussian curvature under external loading.This property provides a new approach to mitigating the pillow effect.Two-dimensional in-plane negative Poisson's ratio materials,such as re-entrant honeycomb structures,chiral structures,and rotating rigid body structures,have been investigated.Hexagonal chiral honeycomb materials exhibit in-plane isotropy and are promising candidates for deployable reflector antennas.Through optimization of traditional hexagonal chiral honeycomb structures,it has been demonstrated that negative Poisson's ratio materials can effectively alleviate the pillow effect in mesh antennas and are feasible for use in mitigating this effect in reflector antennas. Conclusions and Prospects This paper summarizes previous research approaches for mitigating the pillow effect and,based on recent results from the authors'research group,explores the feasibility of using the curved-surface bending characteristics of negative Poisson's ratio materials to address this issue.This approach is expected to reduce the number of adjustment points in existing mesh antennas,optimize the antenna struc-ture,and reduce overall mass.In the future,the following aspects require further investigation:1)design and optimization of negative Poisson's ratio materials;2)macro-scale homogenization analysis;3)investigation of the out-of-plane stiffness of the materials;and 4)prototype develop-ment and experimental validation.