| [0002] The present invention relates generally to a Balun, and more particularly, to planar Balun applied to the field of solid-state microwave generator and radio frequency element manufacturing and a power amplifier using the planar Balun; the planar Balun of the present invention can be used in various hundred-watt and kilowatt-class push-pull power amplifiers, and the use of the planar Balun of the present invention can greatly reduce the area of the power amplifier and the amount of second harmonics, and improve the flexibility of circuit layout and spectral purity respectively, especially above 915MHz, the present invention can replace the widely used coaxial Balun and simplify amplifier design; the push-pull power amplifier of the planar Balun applied in the present invention can provide microwave output of hundreds to kilos of watts at 915MHz or higher frequency, and applied to various phase-controlled microwave heating systems and plasma systems. |