### Abstract

Original language | English |
---|---|

Pages (from-to) | 829-837 |

Number of pages | 9 |

Journal | IEEE Transactions on Antennas and Propagation |

Volume | 49 |

Issue number | 5 |

DOIs | |

Publication status | Published - 2001 |

MoE publication type | A1 Journal article-refereed |

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### Cite this

*IEEE Transactions on Antennas and Propagation*,

*49*(5), 829-837. https://doi.org/10.1109/8.929637

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*IEEE Transactions on Antennas and Propagation*, vol. 49, no. 5, pp. 829-837. https://doi.org/10.1109/8.929637

**Quality factor of an electrically small antenna radiating close to a conducting plane.** / Sten, Johan; Hujanen, Arto; Koivisto, Päivi.

Research output: Contribution to journal › Article › Scientific › peer-review

TY - JOUR

T1 - Quality factor of an electrically small antenna radiating close to a conducting plane

AU - Sten, Johan

AU - Hujanen, Arto

AU - Koivisto, Päivi

PY - 2001

Y1 - 2001

N2 - Expressions are derived for the smallest achievable radiation quality factor (Q) of an electrically small antenna in front of a conducting plane. Applying the low-frequency approximation to the source region involving an electric or a magnetic point dipole plus their images behind the plane, an expression is formed for the field in the radiation zone. The contribution of non-propagating energy in the near field is obtained explicitly using a spherical harmonics decomposition. The radiation Q is found to depend on the radius (relative to wavelength) of the smallest sphere that encloses the antenna and its image, the ratio of the vertical and horizontal dipole moments, as well as the positions of the dipoles relative to each other and to the plane. A number of simple wire structures are analysed with NEC (based on the method of moments), and the approximate Q obtained from their fractional bandwidth are compared to the corresponding theoretical minima.

AB - Expressions are derived for the smallest achievable radiation quality factor (Q) of an electrically small antenna in front of a conducting plane. Applying the low-frequency approximation to the source region involving an electric or a magnetic point dipole plus their images behind the plane, an expression is formed for the field in the radiation zone. The contribution of non-propagating energy in the near field is obtained explicitly using a spherical harmonics decomposition. The radiation Q is found to depend on the radius (relative to wavelength) of the smallest sphere that encloses the antenna and its image, the ratio of the vertical and horizontal dipole moments, as well as the positions of the dipoles relative to each other and to the plane. A number of simple wire structures are analysed with NEC (based on the method of moments), and the approximate Q obtained from their fractional bandwidth are compared to the corresponding theoretical minima.

U2 - 10.1109/8.929637

DO - 10.1109/8.929637

M3 - Article

VL - 49

SP - 829

EP - 837

JO - IEEE Transactions on Antennas and Propagation

JF - IEEE Transactions on Antennas and Propagation

SN - 0018-926X

IS - 5

ER -