Modeling antennas printed on magnetized substrate: Application to the design of a tunable PIFA antenna

A miniature reconfigurable PIFA antenna (Printed-Inverted-F-Antenna) is investigated in this paper. This antenna is printed on magneto-dielectric substrate. The tunability is achieved by the application of an external DC magnetic biasing field, thanks to the field-dependent permeability of the substrate. In order to design this antenna a modeling tool is implemented. It consists in coupling a magnetic material model and EM simulator. The “General Permeability Tensor” (GPT) model is used in order to determine the permeability tensor whatever the magnetization state of the substrate is. The coupling of the GPT model with an electromagnetic simulator (CST Microwave Studio R ®) allows for the complete description of microwave characteristics of the antenna. The confrontation between the measurement and simulation for different applied DC biasing fields allows enhancing and validating the theoretical approach developed.