Integrated low noise amplifier with notch filter using DMS technique for ultra-wideband application

The work presents a design of single stage integrated low noise amplifier using negative feedback and inductive source degeneration with DMS technique as the notch filter. Implementation of Super-low noise InGaAs HEMT MGF4937AM transistor which covers from 3.1-10.6 GHz for LNA. Due to interference from IEEE 802.11 WLAN at 5-6 GHz in UWB standard, a notch filter is used to attenuate the undesired frequency band from the LNA. Introducing negative feedback and inductive source degeneration improve the stability of the LNA at the same time provide wideband characteristic and gain flatness for the entire band. DMS technique used as notch filter because of its microstrip characteristic which easily to integrate with other microstrip devices. This LNA integrated notch filter design is based on FR4 microstrip and designed using Advanced Design System (ADS) software. The LNA integrated notch filter provides an input return loss (S11), output return loss (S22) which less than -10 dB, the gain (S21) more than 10 dB and noise figure less than 2 dB from 3.1 to 5 GHz. From 5-6 GHz, the gain and noise figure is degrading which indicate that the particular frequency band is rejected. From 6-10 GHz, all the parameters return as the original signal.