A low power RF CMOS direct-conversion transmitter using high conversion gain front end for IEEE 802.15.4 standard

This paper introduces a direct conversion transmitter for IEEE 802.15.4 applications with a high gain up-conversion mixer. An RF DCT (Direct Conversion Transmitter) is composed of differential-ended DAC (Digital to Analog Converter), passive low pass filter, quadrature active mixer, and drive amplifier. The most important thing in designing RF direct conversion transmitter is satisfying 2.4GHz Zigbee standards with using low power and compact cell configurations. Active mixer provides enough high gain as well as sufficient ACPR (Adjacent Channel Power ratio) performance.