Design of UWB LNA with interference rejection using coupled inductors

In this circuit, a UWB LNA circuit with new input stage is proposed. In this scheme, a combination of coupled inductors and a new structure based on notch filter in input stage is utilized. As a result, the input stage is able to easily reject in-band and out-band interference with 43.2 dB and 25.1 dB respectively. This input stage is applied in an LNA. The simulations verify that the LNA has a peak gain of 25.9 dB in 3.1-4.8 GHz and a peak gain of 18.62 dB in 6.1-10.6 GHz frequency band while minimum NF in mentioned frequency bands are 1.33dB and 1.8 dB, respectively. This circuit rejects in-band and out-band interference 60.3 dB and 26.4 dB, while LNA core consumes 14.59 mW DC power from 1.8 V power supply. The input reflection coefficient (s
₁₁
) is less than -8.8 dB over low and high frequency band since worst value of IIP3 over entire bandwidth is -23 dBm which occurs at 3.1 GHz.