A study on miniaturization of a handset antenna utilizing magnetic materials

One of the trends observed in the cellular phone technologies is to dramatically reduce the size and the weight of the handset. Accordingly antennas used for such handsets must also follow downsizing of the handset unit. In particular, built-in antennas are required recently. In this paper, we investigate a downsizing technique of antennas for handset by utilizing a magnetic material. Firstly, basic characteristics of PIFA (planar inverted-F antenna) which is popular built-in antenna for handset, are obtained by the HFSS electromagnetic simulator, and calculated results are compared with measured results. Secondly, change of resonance frequency of PIFA is examined by arranging various types of magnetic materials. Suitable configuration and arrangement of magnetic materials are found. In a result the possibility of miniaturization of PIFA is confirmed by utilizing magnetic materials.