Design of a polarisation reconfigurable patch antenna using ferrimagnetic materials

In this study the authors introduce the utilisation of ferrimagnetic compounds into an antenna design and investigate the capability of controlling the antenna properties by means of an external magnetic field. After intensive study of the material properties, the ferrimagnetic compound yttrium iron garnet (YIG) was found to be the best candidate for the proposed novel antenna design. The authors provide a patch antenna design with a part of the dielectric substrate replaced by YIG compound. They have investigated the influence of this compound on the antenna´s polarisation properties under the application of an external magnetic field. The authors clearly demonstrate that the type and the sense of the antenna polarisation are strongly influenced by the YIG substrate, because they change with respect to the direction and the magnitude of the external magnetic field. Moreover, the authors have proved that the presence of this material induces non-reciprocal properties in the antenna´s operation, changing the antenna properties with respect to receiving or transmitting mode.