US Patent 7782165 Wire-stacked transformer

A wire-stacked transformer has a first loop supplied with electric power and built with one or more metal plates forming a magnetic field, a second loop disposed in a concentric circle with the first loop and generating induction current, and loop wires disposed between the respective metal plates of the first loop and supplying electric power to each metal plate. Accordingly, efficiency of a power amplifier can be enhanced by reducing the loss of the DAT.