A wideband 0 to 60 dB CMOS variable gain amplifier for IR-UWB I/Q receivers

This paper reports on the realization of a variable gain amplifier (VGA) with an automatic gain control (AGC) loop for impulse-radio ultra-wideband (IR-UWB) signals. The circuit shows a gain range between 0 and 60 dB and a -3 dB bandwidth larger than 180 MHz over the whole gain range. The VGA also features a dual channel implementation for quadrature signal demodulation and shows very small I/Q imbalance. The circuit is fabricated in 0.18 mum technology, draws less than 5 mA from a 1.8 V supply voltage and occupies an area 1 mm².