Design of high gain and low noise figure on-chip LNA for Ku band application

Abstract

Low Noise Amplifiers (LNA) are key components in the receiving end of nearly every communication system. Primary purpose of the LNA is to amplify the received signal while at the same time adding as little additional noise as possible. Its performance greatly affects the overall receiver performance. This thesis discusses design of narrow band low noise amplifiers for Ku band applications. The target of this thesis is to design a LNA at 17 GHz for Ku Band. It also addresses some of the main aspects of microwave LNA design for use in the Ku frequency band. Through evaluation of the published literature on the LNA designing, a circuit topology has been selected, explored and redesigned. The tradeoffs related to input and output mis-match, bandwidth and gain has been explored and discussed. Finally, LNA has been designed in 0.09 um CMOS process using Agilent’s ADS having off-chip and on-chip inductors. On-chip inductor technique reduces the contribution of spectral noise current due to inductor series resistance and provides a good matching at the LNA input and output. After resonance frequency inductor starts behaving like a capacitor. By the help of on-chip inductor, resonance frequency can be controlled. As this design includes on-chip rectangular spiral inductors, the design, and modeling of on-chip inductors have been discussed briefly.