Simulation of Electromagnetic Performance on Mesh Reflector Antennas: Three-Dimensional Mesh Structures With Lumped Boundary Conditions

Reflector antennas with mesh surfaces have been extensively used in satellite antenna systems. The electrical contact at the metal-insulator-metal (MIM) junction points may cause the degradation of reflectivity performance, and the concept of MIM junctions is mainly used for the analysis of passive intermodulation (PIM) arising from metallic contact in the practical antennas. In this work, a three-dimensional (3-D) modeling of mesh surfaces is presented, which introduced impedance connections at the wire junctions of metallic contact area. The electrical contact model of impedance connections is equivalent to a circuit model, which is considered as lumped boundary condition extended to the modeling of mesh. The planar mesh reflection coefficients are constructed using a full-wave frequency domain method with Floquet mode expansion. To calculate the electrical performance of curved mesh antenna, a solid surface with an equivalent loss is adopted to replace the mesh surfaces. The reflection coefficients of the equivalent loss material are the same as for the mesh surfaces. The analysis of the planar mesh reflectors with three different connections (solid surface, perfect contact, and lumped connection) at junction points is performed as an example for the proposed model. The results demonstrate the usefulness of the model in accurate performance prediction of mesh reflector antennas. Finally, a mesh reflector antenna with 3-D mesh structures is analyzed to predict the electrical performance of the antenna.