Coupling of Two Rectangular Waveguides Through a Diaphragm With a Dielectric Slab in the Slot

Abstract

A scattering problem for two semi-infinite rectangular waveguides coupling through a narrow slot cut in the common end wall of the two waveguides is solved. The slot is partially filled with a dissipative or perfect dielectric insert. A mathematical model based on continuity of tangential components of magnetic field vectors on both surfaces of the diaphragm in the coupling waveguides is proposed. The magnetic field in the slot is represented by a set of slot eigenwaves. The electrical field distribution function is used as a basis function in the Galerkin's procedure allowing to find unknown amplitude coefficients. Simulation and experimental measurement have been carried out. Dependences of scattering parameters upon the wavelength were studied for various geometric parameters, insert position in the slot, and insert material permittivity and losses. A good agreement between simulation results and experimental data is obtained. It was shown that an estimate of the insert permittivity and losses can be done for unknown materials using experimental and simulated data.