Strong boundary effects in microwave metamaterial samples

摘要

The majority of metamaterial ideas are expressed in terms of effective material parameters. However, in many cases that kind of description fails, for a number of reasons such as strong spatial dispersion. One of the less known problems stems from the finite size of realistic metamaterials, which makes the total number of individual elements insufficient for an effective medium description, and promotes significant boundary effects. We present an analysis of this situation and point out that even for ideally shaped metamaterial samples there is a remarkable difference from theoretical predictions. As an example, we report the implications of finite size for metamaterial lenses.