Improved two stage ultra-wideband CMOS low noise amplifier with out band rejection using low noise active inductor

A two stage 3.2-6.3 GHz Ultra Wide-Band CMOS Low Noise Amplifier with out-band rejection topology by using modified low noise Active Inductor with 0.18μm CMOS technology is presented in this paper. Due to the Federal communication commission´s power limitation on the transmitting signal at transmitter, the receiver signal power of the UWB system is very smaller than interferer narrow-band signals. To avoid this interference and to get the original received signal at receiver side the characteristic of interference rejection must be at receiver. As the low noise amplifier is very first stage of the receiver, here in this paper we proposed a wide-band input network with out-band rejection capability to suppress the out-band properties as its first stage of LNA. Source degenerated cascode Amplifier is used as the amplifier stage of LNA. To attenuate more the out-band rejection characteristic without influencing the input matching, a dual band Notch filter with the low noise Active Inductor is used as the second stage. An Active Inductor circuit has been designed to modify with respect to improve its Quality factor as well as to reduce its noise, as comparatively an Active Inductor has lowered the noise performance than the Passive Inductors. There is maximum 75-85 dB out-band rejection has been measure with the power gain of almost 15dB and 0.9 nV/sqrt(Hz) the minimum power spectral density has been measured while consuming a DC power of 4.7mW.