A Novel Wideband Filter using Open Split Ring Resonators ☆

A small wideband bandpass filter using metamaterial (MTM) structure is proposed in this paper. The novel filter is printed on Rogers 3010 substrate with a dielectric constant of 10.2 and 1.27 mm thickness. To achieve broadband design, we developed a Composite Right/Left Handed (CRLH) line based on Open Split Ring Resonators (OSRRs) on coplanar waveguide transmission line (CPW). The CRLH unit cell (or MTM unit cell) includes two OSRRs which are connected by a stripline. Then the proposed filter is constructed by connecting two MTM unit cells in series using a stripline between two outer rings. Two open stubs are added between MTM cells to create a transmission zero that improves the upper stopband performance while S21 characteristic at the lower stopband is remained. The fabricated filter exhibits a 3-dB fractal bandwidth of 98% with a low insertion loss of less than 0.78 dB over the passband. Measured results are proved the performances of the proposed filter