Title :
Electric Dipole Antennas With Magnetic-Coated PEC Cores: Reaching the Chu Lower Bound on
Author_Institution :
Dept. of Electr. Eng., Electromagn. Syst., Tech. Univ. of Denmark, Lyngby, Denmark
fDate :
3/1/2012 12:00:00 AM
Abstract :
The radiation properties of spherical electric dipole antennas with electric current excitation and material-coated perfectly electrically conducting (PEC) cores are investigated analytically using vector spherical wave functions. Closed-form expressions for electric and magnetic stored energy as well as the radiation quality factor Q are derived. Using these, it is shown that properly selected magnetic coating and radius of the PEC core vastly reduce the internal stored energy, and thus make the Q of an electric dipole antenna approach the Chu lower bound.
Keywords :
Q-factor; antenna radiation patterns; dipole antennas; Chu Lower bound; PEC core radius; electric current excitation; electric stored energy; magnetic stored energy; magnetic-coated PEC cores; material-coated perfectly-electrically-conducting cores; radiation properties; radiation quality factor; spherical electric dipole antennas; vector spherical wave functions; Dipole antennas; Magnetic cores; Magnetic resonance; Permeability; Q factor; Chu lower bound; electric dipole; electrically small antennas; fundamental limitations; quality factor;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2011.2180331