A UWB transformer-C orthonormal state space band-reject filter in 0.13 μm CMOS

An RF passive orthonormal ladder filter using transformers is presented, where the output is obtained from a linear, weighted combination of the voltages or currents at predetermined nodes or branches. With this topology, arbitrary rational transfer functions can be mapped onto silicon. Key features of this single-input, multiple-output (SIMO) topology include low-pass to band-pass/reject transformation without doubling the order of the filter and the realization of transmission zeros in the right-half-plane (RHP) (for superior approximations). As a proof of concept, a 7^th order transformer-C filter implemented in CMOS 0.13 mum technology that can be used as a pulse shaping network (pulse width less than 0.5 ns) or band selection filter (offering a minimum of 20 dB attenuation at the IEEE802.11a WLAN band) for UWB transceivers is presented.