Simple approximate models of waveguide bends

Recently, a new accurate and rigorous analytic-numerical analysis of guide bends has been carried out. The matrix model obtained is based on the spectral operator method. The approach developed reduces the problem to a matrix operator equation of the special form. This operator equation has mathematical features that allow firm statements concerning properties of the numerical approximation. It was proved analytically the absence of spurious solutions, the validity of the truncation procedure, the convergence of the computed solution to exact one and robust calculations. Therefore, such formulation is more efficient compared to full numerical methods. In the general case a precise eigenmodal analysis of guide bends is computationally intensive. Therefore, the simple approximate models can be more suitable for use in CAD/CAM tools to design complex millimeter circuits and components. The objective of this paper is to develop some simple models for both H- and E-plane uniform bends in rectangular waveguide.