CPW Cascaded Magnetostatic Wave Band Stop Resonators

A microwave tunable band-stop configuration based on a combination of two cascaded magneto-static wave (MSW) resonators, working at frequencies higher than 10 GHz has been analysed. The structure has been obtained by coupling yttrium iron garnet (YIG) film straight edge resonators (SER) excited by magnetostatic waves (MSW) with a CPW on a silicon substrate. The utilisation of the coplanar configuration instead of microstrip ones was chosen because the CPW transmission system permits easy shunt connection of the external elements. As a conclusion, the better confinement of the RF field in the region where the SER is placed renders the CPW solution better than the classical microstrip one in terms of electrical coupling between resonator and transducer. The presence of two resonators, almost identical between them but not perfectly equal, enhances the mode better coupled, i.e. the main one, vs. the high order modes, having lower amplitude and more critical to be excited.