A 3-5 GHz UWB LNA with an active balun in 0.18 μm CMOS process

In this paper, a low-power ultra-wideband (UWB) low-noise amplifier (LNA) is proposed. We use shunt-feedback resistor structure for wideband input matching and series L-shunt C structure for gain flatness. Numerical simulation based on TSMC 0.18 μm 1 poly-6 metal process shows that the UWB LNA achieves 18 dB gain at 3-5 GHz band and 3 dB noise figure, operates from 1.8 V power supply, and dissipates 2.63 mW without the output buffer of the LNA. We also propose an active balun to reduce chip size and get more gain by operating it as an amplifier. The differential voltage output of the balun is connected to a double-balanced mixer, which circuit has good performance for isolation.