A study on miniaturization of antenna loaded with magnetic materials by using topology optimization

With the recent rapid progress in handsets, the downsizing of their antennas is acquiring great importance. Generally, these antennas have been downsized by changing a configuration of the antennas or utilizing materials such as dielectric materials and magnetic materials. Until now, we have investigated a downsizing technique of antennas for handsets by utilizing magnetic materials. The topology optimization has significantly been expanded to many optimization problems. This optimization has been used to find the optimal material distribution. In our previous study, we used the topology optimization to optimize the configuration and arrangement of the magnetic materials, which were inserted in PIFA on an infinite ground plane. In this optimization, the finite-difference time-domain (FDTD) method and the adjoint variable method (AVM) were used, and design parameters were permittivity and permeability of the materials. As a result, it was found that the resonance frequency was lowered by utilizing the optimal configuration of the magnetic materials. In this paper, we apply the topology optimization to PIFA on a finite ground plane, which is used in practice, and confirm its validity.