Direct RF subsampling receivers enabling impulse-based UWB signals for breast cancer detection

The implementation of a Direct RF subsampling receiver in CMOS is presented for the application of breast cancer detection using impulse-based ultrawideband (UWB) signals. Such a receiver inherently benefits from CMOS scaling since its speed-accuracy tradeoff depends only on technological process parameters. With a proper choice of antenna matching media, the current signal processing requested resolution could be translated into feasible hardware specifications. The track-and-hold (T/H) circuit is analyzed and implemented in a 40-nm chip since this block must cope with the full RF BW. An effective resolution BW of 5.5 GHz was measured with an accuracy of 6 b for rail-to-rail input signals. Second, a two-stage Miller compensated fully differential difference amplifier is discussed with low input parasitics (10 fF) to enable measurements without limiting the performance.