Development Of Microwave Filters Using Negative Index Transmission Line Metamaterials

This paper demonstrates a filtering action in the form of pass-band and stop-band by utilizing metamaterials with microstrip technology. A hexagonal omega-shaped metamaterial structure is periodically embedded near the signal line (analogous to photonic structures). Additionally, metallic vias are integrated along the microstrip line. The hexagonal omega structure provides a negative permeability effect (µ_eff), while the metallic vias generate negative permittivity (ε_eff) over a specific frequency range. The hexagonal omega across the microstrip line acts as a narrow band-stop filter, while the microstrip line with metallic vias functions as a narrow band-pass filter, achieving 28 dB attenuation at a notch frequency of 4.28 GHz. This work highlights the potential of metamaterial-based microstrip filters for precise filtering applications.