Far-Field Properties of a Line Source-Excited Electrically Small Quadrupolar Metamaterial Cylindrical Shell

An antenna configuration that consists of an arbitrarily located electric line source that radiates in the presence of concentric metamaterial cylinders is examined. With the emphasis on the so-called quadrupolar structure, it is shown that such electrically small configurations may offer significant enhancements of the radiated power. Furthermore, the possibility of controlling the pattern by properly locating the electric line source with respect to the structure, thereby offering a means of obtaining electrically small metamaterial-based directive antennas, is also demonstrated.