A 2.4 GHz CMOS tunable image-rejection low-noise amplifier with active inductor

Abstract

Research and development in radio-frequency integrated circuits (RFICs) have become popular recently and this is due mainly to the high demand for wireless communication devices from the market. Among the various integrated circuits fabrication technologies in use, CMOS technology has become a very attractive option because of its low-cost and high integration. Superheterodyne receiver is at present the most widely used receiver front-end architecture as it exhibits good RF performance. Proper image signal filtering is required and this is done through using external surface-acoustic wave (SAW) filters. However, this results in increased cost and device size (Maeda et al., 2006). To overcome the problem, recent research has focused on imagerejection low-noise amplifier (IR LNA) that uses a notch filter to reject the image signal (Samavati, Rategh and Lee, 2005; Baki and El-Gamal, 2002; Nguyen et al., 2005).