Electrically Small Antennas with Dielectric, Magneto-Dielectric and Metamaterial Loading

With recent advances in manufacture and study of high dielectric ceramics, magneto-dielectrics and metamaterials, there have been renewed interests in studying electrically small antennas. Prospective features of aforementioned loading schemes have been discussed by various research groups, however, there lacks of a fair comparison in antenna performance taking into consideration of material dispersion and losses. This paper presents a comparative study on antenna performance, in particular, the beam pattern, gain, efficiency and bandwidth of three types of material/metamaterial loaded antennas as a function of physical size, electrical size and frequency. Selected antennas are built and tested, measurement results are in good agreement with theoretical predictions.