Polar Transmitters for Wireless Communications

Future wireless communications will require multimode radio transceivers. This article looks at two possible transmitter architectures: direct upconversion and polar modulation. A brief review of the direct upconversion approach reveals some key limitations. This leads to a detailed study of the polar transmitter focusing on its operation, design challenges, and potential benefits. Its multi- mode capability and low power consumption are illustrated by a prototype design of a GSM, EDGE, and WCDMA polar transmitter. The efficiency of the polar transmitter is shown as a key enabler of future systems using OFDM modulation with high peak-to-average signals.