Compact wideband band-stop filter using stepped complementary split ring resonators

The objective of this work is to achieve a compact wideband band-stop filter using complementary split ring resonators (CSRR) as the fundamental element. The relation between the geometry and resonances of the CSRR were studied analytically along with their field distribution to determine the factors governing coupling between the rings of the CSRR. The effects of the inner-outer ring orientation on resonances of the CSRR has been studied and the resulting properties have been used to design the proposed compact wideband band-stop filter prototype operating with a center frequency of 2.5 GHz and a bandwidth of 1 GHz. The area of the proposed filter is 0.078 λg2 with a fractional bandwidth of 39.76%. This structure has following advantages: more compact, wide bandwidth and occupies less area. The fabricated prototype was tested and the results were promising representing this works potential.