Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores

Troels Vejle Hansen; Oleksiy S. Kim; Olav Breinbjerg

doi:10.1109/TAP.2013.2287290

Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores

Troels Vejle Hansen, Oleksiy S. Kim, Olav Breinbjerg

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Abstract

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%.

Original language	English
Journal	IEEE Transactions on Antennas and Propagation
Volume	62
Issue number	1
Pages (from-to)	467-470
ISSN	0018-926X
DOIs	https://doi.org/10.1109/TAP.2013.2287290
Publication status	Published - 2014

Keywords

Fields, Waves and Electromagnetics
Electrically small antennas
Energy storage
Magnetic losses
Quality factor
Spherical antennas

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10.1109/TAP.2013.2287290

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title = "Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores",

abstract = "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%.",

keywords = "Fields, Waves and Electromagnetics, Electrically small antennas, Energy storage, Magnetic losses, Quality factor, Spherical antennas",

author = "Hansen, {Troels Vejle} and Kim, {Oleksiy S.} and Olav Breinbjerg",

year = "2014",

doi = "10.1109/TAP.2013.2287290",

language = "English",

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AU - Breinbjerg, Olav

PY - 2014

Y1 - 2014

N2 - 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%.

AB - 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%.

KW - Fields, Waves and Electromagnetics

KW - Electrically small antennas

KW - Energy storage

KW - Magnetic losses

KW - Quality factor

KW - Spherical antennas

U2 - 10.1109/TAP.2013.2287290

DO - 10.1109/TAP.2013.2287290

M3 - Journal article

SN - 0018-926X

VL - 62

SP - 467

EP - 470

JO - IEEE Transactions on Antennas and Propagation

JF - IEEE Transactions on Antennas and Propagation

IS - 1

ER -

Quality Factor and Radiation Efficiency of Dual-Mode Self-Resonant Spherical Antennas With Lossy Magnetodielectric Cores

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