Canonical sources and duality in chiral media (antenna arrays)

The authors examine the characteristics of antenna arrays embedded in unbounded chiral media using the Green's dyadic for electric sources and the Green's vector for magnetic sources. The purpose is to bring to light the new characteristics of sources, both point and extended, which interact with this medium and to examine general characteristics of sources located in a medium with handedness. Very simple quality relations are presented that are characteristic of chiral media when the results are written in terms of the circular eigenmodes. Appropriate measures of chirality such as the chirality admittance and impedance and a dimensionless chirality factor are introduced as needed. It is shown that, in the far field, both point and extended sources, whether electric or magnetic, radiate two electromagnetic eigenmodes which are of opposing handedness. Sources that access only one of the eigenmodes of the medium are demonstrated. Several applications of the results and array performance in chiral media are noted.<
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