C-band parallel coupled bandpass filter with harmonic suppression using open stub and CSRRs

Design and implementation of a Wideband microwave parallel coupled microstrip bandpass filter (PCMBPF) for C-band applications with suppression of second harmonic frequencies is demonstrated in this paper. This suppression is achieved by embedding separately open stub and complementary split ring resonators CSRRs exactly in the 50 Ω transmission line and below it respectively. Good performances are obtained and compared in term of rejection level and insertion losses in the filter response. Both of the proposed techniques are numerically investigated and easy integrated without increase the filter size. Numerical results for all designs are obtained, while the filters are simulated using CST MWs and fabricated on the Roger RT/Duroid RO3010 substrate with relative permittivity of 10.2 and dielectric thickness of 1.27 mm.