||This thesis deals with two kinds of RF CMOS low noise amplifiers (LNA). The low power LNA and the image-reject LNA.|
The impact of gain, noise figure, and stability on RF CMOS image-reject LNA has been studied. Through this study, the fundamental properties of image-reject LNA can be understood by a simple but physical concept.
A current-reuse RF CMOS source-degenerated cascode LNA is also presented, which adopts a combination of source-degenerated NMOS inverter and Cascode topology to improve gain and noise figure, the existent and well-studied technique from the design standpoint, makes optimization of the stage easy.
A modification of the proposed architecture is also presented, which adopts internal filters to achieve the image rejection without additional image-reject filters that degrade both noise figure and power consumption. It will be a good candidate for low power implementation of CMOS RF-IC.
Both circuits’ parameters except noise figures are simulated using TSMC 0.25 um RF CMOS component models. The noise models considered here include induced gate noise, thermal noise and shot noise . The current-reuse source-degenerated NMOS inverter LNA noise figure is 0.7 dB, forward gain is 16 dB, and IIP3 is -15 dBm. The low power image-reject LNA noise figure is 0.7 dB, forward gain is 16 dB, IIP3 is -16 dBm, and image rejection is 20 dB at 1.6 GHz. Both LNAs operate at 2.4 GHz and consume about 6 mA under a 2.5 V voltage supply.