Micro coil modeling - benefit and implementation of a permeable layer

Abstract Rectangular micro coils which are used in a wide range of applications (e.g. medical or automotive area) are the main components of appropriate wireless transmission systems for frequencies up to 20 MHz. As shown in previous works the self-inductance of micro coils has to be maximized to achieve a higher working distance. This can be done by the usage of a permeable layer underneath the micro coil. The existing model of the micro coil is extended by the use of the magnetic image method to include the inductance yield caused by the permeable layer. The underlying permeable layer or substrate is also modeled accurately to include eddy current phenomena and parasitic elements. To do this, the layer and the substrate respectively are divided into segments analog to the structure of the micro coil. Each segment is described by lumped elements. All elements are connected together to build up a network, which will be used to calculate the terminal impedance. The model and first results will be presented.