A polar transmitter for an RFID reader and a system using the polar transmitter are disclosed. An RFID system according to at least some embodiments of the invention includes a polar transmitter, a receiver to receive responses from RFID tags, and a coupler connected to the polar transmitter, the receiver and one or more antennas. In at least some embodiments, the polar transmitter of the RFID system includes an envelope amplifier and a power amplifier. In some examples, a polar transmitter includes direct conversion of baseband data to provide angle modulation plus drive modulation. In addition to the envelope amplifier and power amplifier, the polar transmitter in such an example includes a quadrature modulator connected to the power amplifier to provide modulation for the transmitter output signal using a Cartesian input signal.