The present invention provides, for use in a radio frequency (RF) transmitter that employs a power amplifier to transmit broadband signals, the power amplifier introducing amplitude and phase distortion, a group delay precompensator circuit. In one embodiment, the group delay precompensator circuit includes: (1) a Cartesian feedback loop coupled between an output of the power amplifier and an input of the RF transmitter; and (2) a group delay compensation block, located in the Cartesian feedback loop, that introduces an opposing phase characteristic into the Cartesian feedback loop and thereby precompensates for the phase distortion. A method of precompensating a group delay and an RF transmitter incorporating the precompensator or the method are also disclosed.