Broadband bandpass filters based on open complementary split ring resonators (OCSRRs) coupled through admittance inverters, and implemented in microstrip technology, are reported. As compared to other broadband filters based on open split ring resonators (OSRRs), ground plane etching is not necessary in the proposed filters. The selectivity of the filters at the upper transition band is improved thanks to the presence of a controllable transmission zero. To demonstrate the potential of this approach, two illustrative prototype devices have been designed and fabricated. © 2012 P. Vélez et al.