From Metamaterial-Based to Metamaterial-Inspired Miniaturized Antennas: a Possible Procedure and Some Examples

In this contribution, we present the procedure employed by our research group to go from metamaterial-based to metamaterial-inspired miniaturized antennas. The concepts of microwave metamaterial-based and metamaterialinspired antennas and components are firstly reviewed. Then, we address the main issues to tackle when going from metamaterial-based to metamaterial-inspired miniaturized antennas. The first issue is related to the anisotropy of the inclusions, which is not usually considered in the preliminary analysis of metamaterial-based antennas. The solution of this issue is given in terms of a deep, though approximated, analysis of the near field distribution of the antennas. The second issue is related to the dimensions of the inclusions, which should be much smaller than the operating wavelength. The solution in this case is found in the miniaturization of the isolated inclusions through different methods. Finally, the third issue is related to the definition of the constitutive parameters of the sample made of a given arrangement of inclusions. An operative solution of this issue is related to the comparison between the transmission and reflection properties of the inclusion-made and the ideal isotropic metamaterial sample. A few design examples are also presented to show the procedure proposed through the paper.