Journal article
Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores
Department of Electrical Engineering, Technical University of Denmark1
Electromagnetic Systems, Department of Electrical Engineering, Technical University of Denmark2
Office for Study Programmes and Student Affairs, Administration, Technical University of Denmark3
Department of Electromagnetic Systems, Technical University of Denmark4
For spherical antennas consisting of a solid magnetodielectric lossy core with an impressed surface current density exciting a superposition of the ${\rm TE}_{mn}$ and ${\rm TM}_{mn}$ spherical modes, we analytically determine the radiation quality factor $Q$ and radiation efficiency $e$ . Also, we determine the relative mode excitation, as a function of the core material parameters, which ensures self-resonance.
For the specific case of a dual-${\rm TE}_{m1}$ , ${\rm TM}_{m1}$ dipole antenna of half a wavelength circumference, we show quantitatively, how $Q/e$ and $e$ behave, and can be optimized as functions of permeability and magnetic loss tangent. We obtain $Q/e$ values well below the Chu lower bound with fair efficiencies up to 71% – 84%.
| Language: | English |
|---|---|
| Publisher: | IEEE |
| Year: | 2014 |
| Pages: | 467-470 |
| ISSN: | 15582221 and 0018926x |
| Types: | Journal article |
| DOI: | 10.1109/TAP.2013.2287290 |
| ORCIDs: | Kim, Oleksiy S. and Breinbjerg, Olav |
Electrically small antennas Energy storage Fields, Waves and Electromagnetics Magnetic losses Quality factor Spherical antennas
Chu lower bound Dipole antennas Magnetic cores Permeability Q-factor TEmn spherical mode TMm1 dipole antenna TMmn spherical mode antenna radiation patterns core material parameters current density dipole antennas dual-TEm1 dual-mode self-resonant spherical antennas energy storage fair efficiencies impressed surface current density magnetic loss tangent magnetic losses permeability quality factor radiation efficiency radiation quality factor relative mode excitation solid magnetodielectric lossy core spherical antennas
