## Minimum Q Electrically Small Antennas

Publication: Research - peer-review › Journal article – Annual report year: 2012

### Standard

**Minimum Q Electrically Small Antennas.** / Kim, O. S.

Publication: Research - peer-review › Journal article – Annual report year: 2012

### Harvard

*I E E E Transactions on Antennas and Propagation*, vol 60, no. 8, pp. 3551-3558. DOI: 10.1109/TAP.2012.2201096

### APA

*I E E E Transactions on Antennas and Propagation*,

*60*(8), 3551-3558. DOI: 10.1109/TAP.2012.2201096

### CBE

### MLA

*I E E E Transactions on Antennas and Propagation*. 2012, 60(8). 3551-3558. Available: 10.1109/TAP.2012.2201096

### Vancouver

### Author

### Bibtex

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### RIS

TY - JOUR

T1 - Minimum Q Electrically Small Antennas

AU - Kim,O. S.

PY - 2012

Y1 - 2012

N2 - Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions for the stored energies obtained through the vector spherical wave theory, it is shown that a magnetic-coated metal core reduces the internal stored energy of both TM1m and TE1m modes simultaneously, so that a self-resonant antenna with the Q approaching the fundamental minimum is created. Numerical results for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q.

AB - Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions for the stored energies obtained through the vector spherical wave theory, it is shown that a magnetic-coated metal core reduces the internal stored energy of both TM1m and TE1m modes simultaneously, so that a self-resonant antenna with the Q approaching the fundamental minimum is created. Numerical results for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q.

KW - Chu lower bound

KW - Circular polarization

KW - Electric dipole

KW - Electrically small antennas

KW - Fundamental limitations

KW - Magnetic dipole

KW - Quality factor

U2 - 10.1109/TAP.2012.2201096

DO - 10.1109/TAP.2012.2201096

M3 - Journal article

VL - 60

SP - 3551

EP - 3558

JO - I E E E Transactions on Antennas and Propagation

T2 - I E E E Transactions on Antennas and Propagation

JF - I E E E Transactions on Antennas and Propagation

SN - 0018-926X

IS - 8

ER -