Title :
Low-Q Electrically Small Spherical Magnetic Dipole Antennas
Author_Institution :
Dept. of Electr. Eng., Tech. Univ. of Denmark, Lyngby, Denmark
fDate :
7/1/2010 12:00:00 AM
Abstract :
Three novel electrically small antenna configurations radiating a TE10 spherical mode corresponding to a magnetic dipole are presented and investigated: multiarm spherical helix (MSH) antenna, spherical split ring resonator (S-SRR) antenna, and spherical split ring (SSR) antenna. All three antennas are self-resonant, with the input resistance tuned to 50 ohms by an excitation curved dipole/monopole. A prototype of the SSR antenna has been fabricated and measured, yielding results that are consistent with the numerical simulations. Radiation quality factors (Q) of these electrically small antennas (in all cases ka <; 0.26) approach the limit of 3.0 times the Chu lower bound for a given antenna size, which is in line with a theoretical prediction made by Wheeler in 1958.
Keywords :
antenna radiation patterns; dipole antennas; helical antennas; resonators; MSH antenna; S-SRR antenna; SSR antenna; TE10 spherical mode; electrically small antenna configurations; electrically small spherical magnetic dipole antennas; excitation curved dipole; excitation curved monopole; multiarm spherical helix antenna; radiation quality factors; spherical split ring antenna; spherical split ring resonator antenna; Antenna measurements; Antenna theory; Dipole antennas; Electric resistance; Electrical resistance measurement; Helical antennas; Numerical simulation; Optical ring resonators; Tellurium; Virtual prototyping; Chu limit; electrically small antennas; magnetic dipole; quality factor; split-ring resonator (SRR); surface integral equation;
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2010.2048863