A broadband pulse generator (PG) for ultra-wideband (UWB) systems, which includes a Gaussian pulse generator, 5 double balanced (DB) Gilbert-cell up-converter mixers, an analog adder, and an LO clock generator unit, respectively, was fabricated in 65 nm CMOS. Measurement shows that generated dc-free multi-tone pulse has a fiat spectrum and linear phase change within 1 GHz bandwidth, with a peak-to-peak amplitude of 280 mV and linear phase change. The die area is only 0.082 mm(2) and power consumption is similar to 4.5 mW from a 1 V supply.