A Low-Voltage Fully-Integrated 4.5-6-GHz CMOS Variable Gain Low Noise Amplifier

A 4.5-6 GHz CMOS low-voltage wideband variable gain low noise amplifier (VGLNA) with wide gain-control range has been demonstrated in this paper. The VGLNA, operating at a supply voltage as low as 1 V, achieves a small signal gain of 20 dB and 3-dB bandwidth of 1.5 GHz with good return losses. The noise figure is 3.5 dB at 5.5 GHz. A figure-of-merit for gain efficiency (Gain/PDC) of 1.23 dB/mW is achieved, which is believed to be the best among reported results for a CMOS VGLNA operating at multi-GHz frequency.