A robust CMOS RF front-end design for 3.1–4.8GHz MB-OFDM UWB system

This paper presents a robust RF front-end for 3.1-4.8-GHz direct-conversion Ultra-wideband (UWB) applications such as the MB-OFDM UWB. The circuits contain a gain controllable low-noise amplifier (LNA) with resistive feedback, a merged quadrature mixer with static current injection, and local oscillator (LO) buffers. Post-layout simulations show that the fully differential front-end achieves a maximum conversion gain of 25.5 dB and a minimum of 16.5 dB, an input return loss of better than -8 dB, a minimum noise figure of 4.5 dB in high-gain mode and an input referred 3^rd intercept point (IIP3) of -4.3 dBm in low-gain mode while drawing 26.3 mA current from a 1.8-V supply without the buffers. The ESD protected chip is implemented in a 0.18-¿m CMOS technology with an active area of 0.48 mm².