Multiple passband circular cavity substrate integrated waveguide filter using asymmetric complementary split ring resonators

This paper presents a novel structure for designing compact multiple passband filters based on circular cavity substrate integrated waveguide (SIW) loaded with complementary split ring resonators (CSRRs). CSRRs of asymmetric semicircular geometry are introduced to generate multiple passbands. Dual passband and quadruple passband are designed and generated below the waveguide cutoff frequency with significant stopband rejection, good selectivity and compactness. The resonating frequencies of the passband can be independently controlled just by varying the dimensions of the loaded CSRRs.