RF Field Build-up inside a Manned Space Vehicle using Novel Ray-Tracing Algorithm

The radio-frequency (RF) field mapping and its analysis inside a space vehicle cabin, although of immense importance, represents a complex problem due to its inherent concavity. Further hybrid surface modeling required for such concave enclosures leads to ray proliferation, thereby making the problem computationally intractable. In this paper, space vehicle is modeled as a double-curvatured general paraboloid of revolution (GPOR) frustum, whose aft section is matched to an end-capped right circular cylinder. A 3D ray tracing package is developed that involves an uniform ray launching scheme, an intelligent scheme for ray bunching and an adaptive reception algorithm for obtaining ray path details inside the concave space vehicle. Due to non-availability of image method for concave curvatured surfaces, the proposed ray-tracing method is validated w.r.t. the RF field build-up inside a closed lossy cuboid using image method. The RF field build-up within the space vehicle is determined using the details of ray-paths and the material parameters. The results for RF field build-up inside a metal-backed dielectric space vehicle are compared with that of highly metallic one for parallel and perpendicular polarizations. The convergence of RF field within the vehicle is analyzed w.r.t. the propagation time and the number of bounces a ray undergoes before reaching the receiving point