US Patent 7521996 Differential amplifier and radio system with a differential amplifier

A radio system for communication is provided that has a differential amplifier for amplifying a transmission frequency, particularly 2.4 GHz, wherein the differential amplifier has a first inductor, which is magnetically coupled to a second inductor, and a capacitor. The capacitor, the first inductor, and the second inductor are wired into a resonant circuit in such a way that the resonant circuit has a common-mode impedance for a common-mode signal and a push-pull impedance, different from the common-mode impedance, for the push-pull signal.