High-efficiency OFDM power amplifier system Using a new polar modulation technique

This paper presents a high-efficiency OFDM power amplifier system using a new polar modulation technique. Proposed amplifier system employs a current control by changing the common-gate stage bias in a cascode amplifier. The input signal is separated into the phase component for a quadrature modulator and amplitude component for an output power controller. Here, some modification of the amplitude component is required. In contrast to our system, traditional polar modulation systems employ a power supply modulator to control output power. The proposed OFDM amplifier system exhibits overall efficiency of 41.3 % at -25dB EVM which satisfies the requirement of IEEE 802.11g specification.