Multiband Microwave Metamaterials Based on Optimized Arrangements of Split-Ring Resonators

We present design and accurate simulations of multiband metamaterials that consist of three-dimensional arrangements of split-ring resonators (SRRs). In order to obtain multiband characteristics with resonances at multiple frequencies, SRRs with different sizes are arranged in well-designed grids. As opposed to unit cells with nested SRRs that are commonly used in the literature, using different-sized SRRs in array forms provide better flexibility in choosing resonance frequencies. On the other hand, strong interactions between SRRs may significantly deteriorate the quality of resonances, particularly inter-resonance transparencies. We consider all geometric parameters, i.e., sizes, distances, and numbers of SRRs, in order to design high-performance configurations with excellent transmission properties. Selected designs are further fabricated via low-cost inkjet printing to demonstrate their performances in measurement setups.