Design Of A RF CMOS Receiver Front-end Based On WiMax Standards

WiMAX (World Interoperability for Microwave Access) is a new standard based on the IEEE802.16 family of Wireless Metropolitan Area Network standards. It is data centric and oriented for fixed and mobile applications. WiMAX fills the gap between low mobility data centric standards (eg WLAN) and high mobility of voice centric standards (eg GSM). Although there were other qualified standards (such as 3G and its future versions), WiMAX occupies a larger market and is more tolerant with multiple users to co-exist. WiMax has also been adopted as a new 3G communication standard.In this project, a direct conversion receiver architecture for WiMax 2.3GHz to 3.8GHz and the front-end design are presented. The main blocks of this receiver include a single balanced passive mixer, a wideband low noise amplifier and an I/Q divider. Single-balanced passive mixer can provide a positive power gain of 3dB with a noise figure of 7dB and a flicker noise corner less than 10Hz if driven by an ideal LO. Its iCP1dB is -3.4dBm and iIP3dB is 7.2dBm. Wideband low-noise amplifier provides 14.2dB of gain with a noise figure of 2.39dB to 2.59dB, iCP1dB -4.2dBm, iIP3 -24.6dBm. Current Model Logic I / Q divide-by-two can achieve 700mV output swing amplitude with a 70fF capacitive load in the frequency range from 4.6GHz to 6.8GHz.The entire system can achieve a voltage gain higher than 24dB, a noise figure less than 2dB, a flicker noise corner less than 2kHz, an iCP1dB greater than -27dBm and an iIP3dB greater than -16dBm in the range from 2.3GHz to 3.8GHz.