Theoretical and Experimental Study of Loss Parameters and High Order in OSEL Devices

Non reciprocal devices using the dynamic surface mode can operate on a broad frequency band. However, beyond a given frequency, some higher order modes can propagate and this fact limits the operational bandwidth. A theoretical and experimental investigation of the influence of ferrite slab roughness on modes conversion is presented. A perturbation method, developed in the case of an anisotropic medium, allows the computation of direct and reflected fields in the structure, for a given roughness. A good agreement between theory and experiment has been found with three different roughness. Two examples of particular applications for isolator structure improvement, i.e. very low insertion losses and very broad band devices, are given.