Analysis of electromagnetic scattering from a cavity with a complex termination by means of a hybrid ray-FDTD method

The electromagnetic modeling of engine cavities is a very difficult task because the electrical size of the cavity is very large, while the engine termination is geometrically complex. High-frequency techniques can adequately model the cavity, but perform poorly when applied to the termination. Low-frequency techniques are currently infeasible for such large geometries because of the large memory and computation time requirements. The authors present a hybrid method which combines the most attractive features of the lowand high-frequency techniques. The finite-difference time-domain (FDTD) method is applied to the small region surrounding the termination. The remainder of the cavity is modeled with ray methods. To validate this method, they consider two-dimensional cavities with complex terminations. Their results are compared against those found from a hybrid combination of the modal method and the method of moments