CPW discontinuities-based metamaterial inclusions

In this paper, a new resonance-type metamaterial inclusion based on coplanar waveguide (CPW) discontinuities is proposed. The inclusion consists of series-connected distributed capacitance and inductance on the center strip of a closed-loop modified CPW transmission line. The resonant frequency at which the magnetic coupling between the inclusion and the host transmission line occurs is calculated, and compared to simulated and measured results. In addition, a modified version of the proposed metamaterial inclusion based on increasing the capacitance inside the inclusion to shift the resonance frequency to the left in order to provide extra compactness is designed and fabricated. The paper discusses the advantages of using the proposed inclusions over conventional split ring resonators. Measured and simulated results for both inclusions agree well with the theoretical models which are developed to find the resonant frequencies. The proposed inclusions are suitable for resonance-based microwave components such as filters.