Technologies to increase HF losses in planar structures and their limitations

Planar structures are often used in our days due to advantages like lower profile, lower leakage inductances and better thermal management. Although highly used components like power transformers, power inductors and EMI filters are built using this technique, planar structures must be improved because planar structure technology also has disadvantages like large footprint area, increased parasitic capacitance and low window utilization factor. In order to increase the efficiency of planar EMI filters, the equivalent parasitic capacitance (EPC) and the equivalent series inductance (ESL) must be eliminated and high frequency (HF) losses must be increased. This paper presents a study of technologies that can be used to increase HF losses in a planar structure and the parameters that affect the structures behavior.