US Patent 9935663 Low-loss isolating outphasing power combiner in a radio frequency device

The power combiner circuit includes a transformer having a first primary coil coupled to a first power amplifier (PA), a second primary coil coupled to a second PA, and a secondary coil. The secondary coil supplies a current to an antenna based on a first direction of a first phase of a first amplified constant-envelope signal in the first primary coil with respect to a second phase of a second amplified constant-envelope signal in the second primary coil. A first load impedance is associated with the first PA and a second load impedance is associated with the second PA. The first load impedance and the second load impedance receive currents from the first PA and second PA, respectively, based on a second direction of the first phase of the first amplified constant-envelope signal with respect to the second phase of the second amplified constant-envelope signal.