Design of Low Noise Amplifier Using 0.18 um CMOS Technology

Low Noise Amplifiers (LNAs) for wireless applications have attracted significant research interest and various approaches to the design of narrowband LNAs (operating below 3 GHz) and wideband LNAs(operating above 3 GHz) have been proposed previously. Distributed amplifiers can provide very large bandwidth because of their unique gain-bandwidth trade-off. However large power consumption and chip area make them unsuitable for typical low–power low cost wireless applications. Common-gate amplifiers exhibit excellent wide band input matching but suffer from a relatively large noise figure (NF). Narrow-band LNAs like an inductively degenerated common-source amplifier can also be converted into a wideband one by adding a wideband input matching network However the insertion loss of the passive input matching degrades the NF rapidly with frequency. Resistive-feedback amplifiers have very good wideband input matching characteristics. However low NF and low power consumption can be hardly achieved simultaneously across a large frequency range. Noise cancellation technique is used to relax this trade-off in resistive feed-back amplifiers.