Design of Small-Size Bandstop Filters with Lumped-Element Immittance Inverters on Artificial Transmission Lines

Applications of artificial transmission lines (ATLs) as immittance inverters to design the small-size bandstop filters (BSFs) with the type II Chebyshev characteristic are considered. The use of conventional and metamaterial ATLs consisting of different number of cascaded unit cells is addressed. Characteristics of the BSFs with different ATL-based immittance inverters are discussed. Tunability of the center frequency of a BSF with variable capacitors is investigated.