Improving EMI filters by decreasing their parasitic capacitance

Most electrical and electronic devices can generate or can be affected by EMI (electromagnetic interferences) and that is why EMI filters are a necessary component for all electronic equipment produced today. In most cases, the EMI filter is included in the switch mode power supplies. For a better structural and functional integration of these devices, they are constructed in the last few years in planar technology. Although constructing EMI filters in planar technology offers many advantages, there are some disadvantages too. In order to improve their functionality, the parasitic capacitance placed between the structure´s windings must be reduced and also the losses in the structure must be increased. This paper presents a continuation of previous studies on a smaller planar structure which represents the base of an EMI filter.