| As for the high data-rata, low power consumption and high security, ultra widebandsystem is being concerned and developed widely. The UWB system’s data-rata can up to110Mbps~480Mbps, is considered as the best solution for short distance and high-rata ratawireless communication in the future. And the continuous developments of IC technologymake the low-cost high-performance monolithic RFIC with CMOS process possible. LNAand down mixer as the most important part determines the system’s performance directly.This thesis researched and designed a receiver front-end for3.1-4.8GHz MB-OFDMsystem, including LNA and Down-mixer. The thesis start with the UWB systemspecification, explicitly introducing and calculating the critical parameters of the receiverfront-end; then analysis of the existing receiver structures and selects a zero-IF structure tobe the realization of the UWB receiver; furthermore, analysis of key parameters of the LNAand Mixer such as input matching, noise factor, conversion gain and linearity; finally,optimization and design the LNA and Mixer’s layout according to the experience.It is simulated using TSMC0.18μm1P8M RF CMOS process. The result of thesimulation shows that the low noise amplifier had a maximum gain of13dB with a rippleless than0.2dB in the designed band, input return loss less than-10dB, and a noise figurebelow5dB. and the mixer had a conversion of8dB, IIP3of5.2dBm, and a noise figure of9dB over full band. This circuit dissipates15mw of power from1.8V supply. So thisdesign can be well meet the ultra-wideband and low power requirements of UWB system.. |
