The Research And Design Of CMOS Low Noise Amplifier

With the rapid development of the communication technique and the growing demand of the markets, the better performance of radio-frequency (RF) wireless receivers is requested. As one of microwave or RF components, low noise performance is very important. High quality factor monolithic spiral inductor is the base of design high performance Low Noise Amplifier (LNA). As first stage of the receiver, the performance of LNA directly affects its performance. Therefore it is significative to research LNA.This paper starts with the research of high quality factor inductor. Based on the review of integrated inductors given and the structure and model of integrated inductors introduced, a high Q transformer-type CMOS inductor for 1.8GHz LNA is designed. In the LNA design, cascode source degeneration structure and interstage inductor are adopted. Based on the RF integrated circuits simulation software (ADS), the designed LNA is matched, simulated and optimized.In the first part of this paper, it introduces the trend of LNA and the open problem of LNA design. In succession, the present status of inductors has been formulated; in this part, the quality factor of transformer-type inductor is also theoretically analyzed in principle and simulated in ADS software. Thirdly, it details the basic theory of LNA design and the matching method; in this part, it has also explored deeply the parameter directive used to judge the stability and the noise parameters of the circuit. Finally, the simulation results of the designed LNA employing active load and passive load are analyzed and compared. A conclusion that the Noise Figure (NF) of LNA can be lower by using high quality factor inductor as active load can be drawn.