Broadening of Resonance With the Bending of Strongly Coupled Strip Resonators in a Planar Terahertz Metamaterial

This research article focuses on investigating the broadening of fundamental resonance in a terahertz metamaterial via the bending of strip resonators placed in close proximity. The two side resonators are bent to an optimum angle with respect to the straight middle resonator to enhance the bandwidth of a terahertz resonance. We study in depth the role of the addition of strip resonators and their bending on the enhancement of bandwidth. From single to double and then triple resonators bent at optimum angle, we observe an enhancement in the bandwidth from 160 GHz to 350 GHz. This remarkable enhancement of over 200% in the bandwidth compared to the single strip resonator is attributed to strong coupling between the resonators placed in the near field configuration. The samples are fabricated using photolithography in the clean room ambiance and characterized using terahertz time-domain spectroscopy. The results from experimental measurements match well with the numerically simulated results as well as with the theoretical harmonic oscillator model. The planar metamaterial exhibiting a broadband resonance response holds the potential for extending the properties of metamaterial over a broad frequency range for applications such as broadband modulation, bandstop filters, etc.