A linear ultra wide band low noise amplifier using pre-distortion technique

This paper presents an Ultra Wide-Band (UWB) high linear low noise amplifier. The linearity of Common Gate (CG) structure is improved based on pre-distortion technique. An auxiliary transistor is used at the input to sink the nonlinear terms of source current, resulting linearity improvement. Furthermore, an inductor is used in the gate of the main amplifying transistor, which efficiently improves gain, input matching and noise performance at higher frequencies. Detailed mathematical analysis show the effectiveness of both linearity improvement and bandwidth extension techniques. Post-layout simulation results of the proposed LNA in TSMC 0.18 µm RF-CMOS process show a gain of 13.7 dB with −3 dB bandwidth of 0.8-10.4 GHz and minimum noise figure (NF) of 3 dB. Input Third Intercept Point (IIP3) of 10.3-13 dBm is achieved which shows 8 dB improvement compared to conventional common gate structure. The core circuit occupies an area of 0.19 mm2 including bond pads, while consuming 4 mA from a 1.8-V supply.