Evaluation of radio frequency CMOS integrated circuit technology for wireless local area network applications

This dissertation evaluated the feasibility of implementing a 2.4-GHz transceiver for wireless LAN applications in a 0.25-μm CMOS process which has comparable over-all performance as a commercial SiGe HBT transceiver and developed understanding of observed differences.; CMOS low noise amplifier (LNA) and mixer are first designed and tested as these two receiver components usually have more stringent and challenging specifications. Their performance is compared to that of SiGe BJT LNA and mixer. It is shown that CMOS LNA and mixer can match the SiGe performance with a 15 to 20% increase in bias current, indicating that a full CMOS transceiver chip is feasible. CMOS and BJT RF circuits are compared at fundamental device physics level as well as process and manufacturing level. MOS and BJT device variations due to process and temperature are evaluated for RF tuned circuits with different Q values. Based on these discussions and LNA design experience, a unique design methodology, Q based design approach, is presented. It is believed that this approach can significantly reduce the risk of RF IC design. Next, a frequency synthesizer, which is the most complex component of the transceiver, is realized in the CMOS process. The desired frequency locking is achieved with phase noise close to that of the SiGe synthesizer. Finally the entire CMOS transceiver is designed, fabricated and characterized. All the circuit blocks on the CMOS transceiver are functional and their performance is close to that of the SiGe transceiver. The CMOS prototype chip is also incorporated in a commercial IEEE 802.11b WLAN system (PRISM II.5). For the first time, PRISM II.5 WLAN with a CMOS transceiver is successfully demonstrated. The performance of the CMOS and SiGe radios is close with CMOS radio consuming 5% more current than that for the SiGe radio. The success of this dissertation points out the direction of higher integration and opens the door for many possible future works. (Abstract shortened by UMI.)...