In conventional polar-loop transmitter circuits, using two feedback circuits intended to control the amplitude in an open loop and phase of a power output in closed loop, respectively, during transmission, causes current consumption to increase during delivery of a small power output. Therefore, a complex table has to be prepared in order to correct the nonlinearities in the amplitude-to-amplitude characteristic of the power amplifier and the amplitude-to-phase characteristic thereof. In order to reduce the current consumption required for the delivery of a moderate or small power output, a polar-loop transmitter circuit in which two feedback circuits intended to control the amplitude and phase of the power output respectively are active when the power amplifier delivers a large power output exhibiting strong nonlinearity, and when the power amplifier delivers a moderate or small power output, the amplitude of the power output is controlled in the open loop.