Inverse Source Problem in Non-homogeneous and Metamaterial Background Media: Antenna Synthesis and Performance Bounds

摘要

The central goal of this project was the investigation of the enhancements in antenna performance and in imaging capability by embedding a source or scatterer in a background medium including metamaterials. This effort was motivated mostly by the possibility of embedding antennas in designer background media so as to obtain radiation performance that would not be possible for comparable antennas in free space. This problem was treated in the present work within a general and non-device-specific framework whose predictions (such as performance bounds) under normalized resources are fundamental. The results were discussed addressing separately the cases of small versus large or resonant antennas, with the overall conclusion that for small antennas one can significantly enhance the radiated power or compress source size via antenna substrates under normalized antenna resources, while for larger antennas the use of substrates can significantly enhance both radiated power and directivity (related to the number of essentially independent field modes that can be radiated effectively) under the given resources.