Enhancement of design parameters for tunable ferromagnetic composite-based microwave devices: application to filtering devices

This paper deals with the design of magnetic tunable microwave filtering functions based on the use of ferromagnetic composites embedded in a polymer substrate of a microstrip transmission line. Our investigation focussed on the relevant design parameters of the composite-loaded microstrip structure to determine its best geometrical parameters in order to increase the device tunability. This analysis was exploited to work out two-stepped impedance filters. The first of them is a single resonator. Its measured scattering parameters evidence a 12 % tenability under a 250-G applied bias field. Through the second-order filter is still under achievement, simulation data let us expect far much lower insertion losses and better performances.