Abstract
The trends for developing high data capacity, high data transmitting rate and low power consumption wireless communication systems are inevitable. To purpose this goal, the recent proposed ultra-wideband (UWB) standards have attracted much interest. The individual RF front-end circuit blocks in the systems are therefore needed to fulfill the wideband operation requirement, which is still a challenge. The main focus of this work is to design various mixers based on currently available CMOS and BiCMOS technologies for both narrow-band and UWB applications. The fundamentals and important design parameters of the receivers and mixers are first introduced, and the advantages and disadvantages of different receiver structures and mixer topologies are discussed. The mixer operation principles and design trade offs are described in detail by analytical equations. Two narrow-band mixers are designed at 5.2 GHz and 2.4 GHz, respectively. By using an on-chip transformer, the supply voltage of the first narrow-band mixer can be decreased to as low as 1.7V resulting in an overall low power consumption of 8.24 mW. In the second narrow-band mixer design, a new active balun is proposed to combine the output differential signal to a single-ended one. The measurement results show a close agreement with the simulated results. In addition, two ultra-wideband mixers are designed based on the narrow-band mixers. We successfully design a multi-stage LC band-pass filter as the input matching network to achieve a perfect wideband matching in these two circuits.