Design and measurement of planar toroidal transformers for very high frequency power applications

The quest for higher power density has led to research of very high frequency (30–300 MHz) power converters. Magnetic components based on ferrite cores have limited application within this frequency range due to increased core loss. Air-core magnetics is a viable alternative as they do not exhibit core loss. The drawback of most air-core magnetics is that the magnetic field is not contained within a closed shape, and it is thus prone to cause electro magnetic interference. A toroidal air-core inductor configuration can be used to contain the magnetic field. This work presents a novel air-core toroidal transformer configuration for use in very high frequency power conversion applications.