Design of Continuously Tunable Low Noise Amplifier for Multiband Radio

This paper presents the design of continuously tunable low noise amplifier with frequency tuning range from 2.2 to 2.8 GHz. The amplifier achieves input matching and tunability through a transformer based input matching network. The proposed circuit uses an inductively degenerated common source cascode amplifier to design the amplification stage. The circuit includes a phase shifter circuit to shift the phase of the input signal to achieve tunability through transformer. The LNA achieves a maximum gain of more than 17dB in the entire tuning range. The LNA attains a perfect impedance match across the tuning range and has a stable operation. In addition, it achieves a low noise figure ranging from 1.4dB to 5.2dB.