A Modular Electromagnetic Model Framework for Evaluation of Radome-type Structures

Radomes serve a vital role in the protection and concealment of radar systems and electronics.  Ideally, the radome minimally attenuates the electromagnetic (EM) signal passing through, meaning that it is nearly transparent to radio frequency EM radiation.  Military radomes serve more complex roles and require complex designs.  On top of protection, this includes broad- and multi-band requirements, unique geometries, advanced materials, and more while maintaining high precision, repeatability, and accuracy.  The EM performance of the antenna is directly impacted by the insertion of the radome and the presence of the airframe creating one system that must collectively be considered.  Other EM phenomena impact system performance as well, including cable coupling, precipitation static, and lighting strikes, among others. In order to meet the various performance requirements while considering the various EM challenges, a holistic modeling approach is needed.  Performance will be further altered under operational conditions, but these fall out of the scope of initial EM modeling and design. Modeling challenges include the need to model large-scale models that require small level details, different time scales in dynamic models, and complex materials such as dispersive, anisotropic, and metamaterials used in radome design.   In order to have a complete EM simulation tool for military radome modeling, these all must be solved in the same solution space and simulation tool. Currently, there is no one solution that can holistically solve the EM modeling of radome. However, the Finite Element Method (FEM) provides an avenue to simultaneously address these challenges through the proper implementation of the established Maxwell’s Equations and boundary conditions, among other governing equations. In order to solve the EM problems, FEM breaks the continuous domain into smaller “finite” pieces or elements that are joined at nodes to represent a discretized domain.  This method was chosen due to its flexibility in treating complex three-dimensional structures, its computational speed, and the availability of open-source algorithms. In addition to this, a pre-processor will be needed to interpret CAD files, create the mesh, and establish boundary conditions, while a post-processor will be needed to view the results. Both of these components will be accomplished through open-source tools to allow for the majority of the time to be focused on integration of the EM Physics and the simulation tool development. Through the establishment, integration, and packaging of these three aspects, a holistic simulation tool that is modular in design to allow for future development will be established. This tool will solve the aforementioned EM problems as well as give a user-friendly, efficient, and robust tool at a significantly reduced cost to the AF end-user.