Promising Future of Metamaterials

This article summarized and reviewed the realization and applications of the waveguide-based metamaterial structures. In particular, an overview of the existing metamaterial elements was presented. We discussed the possible solutions to enable wave propagation below the waveguide cutoff frequency by loading these elements. Then a detailed analysis on those waveguide unit-cells loaded with different metamaterial elements was provided based on HFSS simulation. Various guided and radiated microwave applications based on these novel metamaterial-based waveguide structures were presented. Those obtained simulation and experimental results were found to be in good agreement with the theoretical prediction. These applications also demonstrate that the combination of waveguide structure and metamaterials offers an excellent alternative approach to the design of miniaturized and high-performance microwave components. Waveguide has high-power handling capability and high Q-factor. It also provides a uniform and lossless ε-negative (μ-negative) environment when operated based on the TE modes (TM modes) below the cutoff frequency. This is a promising and potentially rewarding research topic. We are looking forward to achieving more truly high-performance metamaterial devices by taking advantages of these features in the near future.