Rf Front-end Design with Copper Passive Components

In this paper we evaluate the impact of copper passive components on RF circuit performance. A fully-differential RF Front-end is used as a test vehicle to compare the UMC 0.18 micron copper process with a traditional 0.25 micron aluminium process. The RF Front-end contains a balun and a low noise amplifier (LNA) that are designed with spiral inductors and capacitors. Spiral inductor Q values range from 3 to 5 for the aluminium process and increase to 7 to 9 for the copper process, while the fringe capacitor Q values for the copper process are more than twice the Q values for the aluminium process. At the system level, the balun performance is characterized by its insertion loss and the LNA performance is defined by its gain and noise figure. The balun insertion losses are 0.6dB to 0.8dB lower for the UMC process as compared to a traditional aluminium process. The LNA gain is 3dB higher for the copper process and has a sharper bandpass characteristic. The output signals from the LNA are downconverted by a Gilbert cell mixer and amplified by an IF stage. The entire system has been simulated and results from measurements are included to validate our simulation result.