US Patent 7388433 Ground inductance compensated quadrature radio frequency amplifier

The present invention is a quadrature RF amplifier including an in-phase amplifier leg and a quadrature-phase amplifier leg. The nominal gain of the in-phase amplifier leg is substantially different from the nominal gain of the quadrature-phase amplifier leg to compensate for gain imbalances introduced by the ground currents of both amplifier legs sharing a common ground lead. The gain imbalances are as a result of voltages developed across the inductance of the common ground lead. Since it is possible to completely compensate for the gain imbalances, reducing the inductance of the common ground lead may be unnecessary.