Patent ID: 8233851

Claim:
A method for improving a linearity of a high-frequency signal transmitter including a power amplifier, an antenna, a transmission line for transferring a high-frequency signal from the power amplifier to the antenna, and an impedance matching circuit connected to the transmission line, the method comprising: designating a comparatively poor linearity region and a comparatively good linearity region by dividing a Smith chart into the two regions based on Adjacent Channel Power Ratio (ACPR) contours drawn on the Smith chart at a point on the transmission line where the impedance matching circuit is connected; measuring a time-dependent reflection coefficient of the high-frequency signal transmitter in terms of a phase and a magnitude; determining whether the reflection coefficient is located in the comparatively poor linearity region or the comparatively good linearity region; and based on a result of the determining, improving the linearity of the high-frequency signal transmitter.