US Patent 7439841 Multi-loop type transformer

A multi-loop transformer includes a first loop built with at least one metal plate forming a magnetic field with electric power supplied; a second loop, disposed in a concentric manner with the first loop, which generates induction current; at least one first sub-loop disposed in the concentric manner with the first loop, and electrically connected to the first loop, the second loop being disposed between the first sub-loop and the first loop; and electric power supply units, disposed between the respective metal plates of the first loop, which supplies electric power to each metal plate. Accordingly, the present invention can improve the efficiency of a power amplifier by reducing the loss of the distributive active transformer (DAT).