Power-efficient switching-based CMOS UWB transmitters for UWB communications and Radar systems

This paper presents a new carrier-based ultra-wideband (UWB) transmitter architecture. The new UWB transmitter implements a double-stage switching to enhance RF-power efficiency, reduce dc-power consumption, and increase switching speed and isolation, while reducing circuit complexity. In addition, this paper also demonstrates a new carrier-based UWB transmitting module implemented using a 0.18-mum CMOS integrated pulse generator-switch chip. The design of a UWB sub-nanosecond-switching 0.18-mum CMOS single-pole single-throw (SPST) switch, operating from 0.45 MHz to 15 GHz, is discussed. The design of a 0.18-mum CMOS tunable impulse generator is also presented. The edge-compression phenomenon of the impulse signal controlling the SPST switch, which makes the generated UWB signal narrower than the impulse, is described. Measurement results show that the generated UWB signal can vary from 2 V peak-to-peak with 3-dB 4-ns pulsewidth to 1 V with 0.5 ns, covering 10-dB signal bandwidths from 0.5 to 4 GHz, respectively. The generated UWB signal can be tuned to cover the entire UWB frequency range of 3.1-10.6 GHz. The sidelobe suppression in the measured spectrums is more than 15 dB. The entire CMOS module works under a 1.8-V supply voltage and consumes less than 1 mA of dc current. The proposed carrier-based UWB transmitter and the demonstrated module provide an attractive means for UWB signal generation for both UWB communications and radar applications