The Impact of Filtering Function on the Design of CMOS Ultra Wideband Filters

This paper provides a large comparison on filtering functions involved in the design of integrated ultra-wideband (UWB) bandpass filters; the aim being to offer designers with an efficient design tool while considering a CMOS technology implementation. Based on major key design parameters, the comparative study enabled deducing that Elliptic, Chebyshev-inverse, and Hourglass functions are the most suitable for UWB operation by exhibiting good performance, i.e., enhanced selectivity, large bandwidth covering the entire frequency range (3.1-10.6GHz), good matching and flatness in the desired band, as well as small variation group delay. Furthermore, applied to the 0.18-μm CMOS technology, the impact of the latter functions on the easiness of implementation in integrated passive device (IPD) technologies and filtering performance was also investigated.