Balanced power amplifier for low power radio communications

The present invention relates to radio telephone communications. Specifically, a power amplifier used in a portable telephone is described for either analog or digital cellular communications. A balanced power amplifier for radio frequencies. The power amplifier may be switched from operating in a saturation mode, so that AMPS-type radio telephone signals may be optimally amplified, to a linear mode so that CDMA signals may be amplified. A directional coupler splits an input signal into quadrature signal components which are supplied to the input of a pair of dual mode power amplifiers. The output signals from the dual mode amplifiers are recombined in a directional coupler. The directional coupler effectively applies all of the output power to an antenna connected to one of the coupler ports, and effectively isolates the output stages of the amplifiers from any reflected power generated by the antenna.