A Spectrum-Shaping Output Stage for IR-UWB Transmitters

This paper presents a novel on-chip wideband balanced-to-unbalanced (balun) transition circuit based on a complementary current inversion method. The proposed circuit features an easily controllable wide bandpass characteristic and is intended to be used as an output stage to filter ill-defined spectra of time-domain ultra-wideband pulses to fit regulation masks. We investigated the circuit in an active topology driven by differential pairs. A mathematical analysis is presented, as well as the implementation of an integrated circuit realized with IBM BiCMOS 0.18-$\mu{\hbox{m}}$ technology.