A SiGe HBT low-power pulse generator for impulse radio ultra-wide band applications

In this paper a compact ultra-wide band (UWB) pulse generator using SiGe HBT technology is presented. The proposed circuit uses a simple circuitry to generate a current spike on chip, which in turn triggers an under-damped resonant circuit. The generated pulses, whose shape is similar to the fifth order derivative of a Gaussian pulse with σ = 60ps, have a short time-domain extension of 200ps FWHM (full width at half maximum), allowing very high repetition rates up to 1.5 GHz (200 MHz is used in the experiments). The spectrum of the generated pulse train is centered around 6 GHz with a 10-dB bandwidth of 5.6 GHz, which complies well with the FCC spectral mask for indoor UWB devices. In the time domain, pulses have a peak-peak amplitude of 120 mV. The power consumption is 4.6 mW at 200 MHz, and 6mW at 1.5 GHz pulse repetition rates. This compact design occupies a chip size of 0.18 mm² including pads.