Abstract: The high-directivity directional coupler of the present invention allows the coupler to maintain high-directivity when the stripe line distance between the mainline metal segment and at least one coupling metal segment is relatively large, to avoid material breakdown by a strong electric field under high-power operation, and is suitable for accurate power measurement in high-power RF systems.

Abstract: The planar Balun of the present invention can be used in various hundred to and thousand-watt level push-pull power amplifiers, which can greatly reduce the area and the amount of second harmonics of the power amplifier, and improve the flexibility of circuit layout and spectral purity, especially at high frequencies, such as around 915 MHz, and can replace the widely used coaxial Balun to simplify amplifier design.

Abstract: A balun includes a substrate, a balanced port, and an unbalanced port. The balanced port disposed on a first configuration surface of the substrate includes a first metal configuration section, a second metal configuration section, and two balanced terminals respectively disposed at one end of the first metal configuration section and one end of the second metal configuration section. The unbalanced port is disposed on a second configuration surface of the substrate corresponding to an arrangement of the balanced port to form an overlapping coupling with the balanced port. The unbalanced port includes a third metal configuration section and an unbalanced terminal disposed at one end of the third metal configuration section. A first orthographic projection on the substrate formed by the first metal configuration section and the second metal configuration section jointly is overlapped with a second orthographic projection on the substrate formed by the third metal configuration section.