A Low Power Programmable CMOS Circuit for Generating Modulated Pulses for UWB Applications

This paper describes the use of a digital to analog converter (DAC) based circuit structure for generating modulated Gaussian pulses for low (3.1 to 5 GHz) and high (6 to 10.6 GHz) UWB bands. The voltage references in DAC circuit are obtained by piecewise constant approximation of the pulses. Experimental results with HSPICE using a 0.18 mum CMOS technology with 1.8 V power supply are given for modulated Gaussian pulses with 4 and 8 GHz center frequencies, which resemble 4 and 6 order derivative of the Gaussian pulse. The power consumptions are, respectively, 0.82 mW and 1.26 mW for the main circuit in low and high UWB bands. Since the circuit structure is simple, both the power consumption and the area are relatively much lower than the existing pulse generators. Also, generating sub-nanosecond signals for high UWB band is due to simplicity of the circuit, which otherwise would require a CMOS technology with finer feature size.