Radiation Q of a small antenna enclosed in an oblate spheroidal volume:: Transverse-to-axis polarisation

被引:9
作者
Stén, JCE [1 ]
机构
[1] VTT Informat Technol, Tech Res Ctr Finland, FIN-02044 Espoo, Finland
关键词
radiation Q; small antennae; physical limitations; spheroidal wave-functions; spheroidal modes;
D O I
10.1078/1434-8411-54100162
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
Radiation quality factor, Q, of an electrically small lossless structure that fits an oblate spheroidal volume for transverse-to-axis polarisation is investigated. Q is evaluated for different size and shape of a spheroid by integrating numerically the stored energy associated with radiation. It is found that Q depends on the distribution of power amongst the various spheroidal modes, and a minimum of Q is achieved by suitable optimisation of the relative amplitudes of these modes. A graphical comparison between the minimum Q of a transversally polarised oblate and an axially polarised prolate spheroid is provided for ellipticities in the range 0.2...., 1. The inverse of the obtained minimum Q serves as an estimate for the bandwidth potential of an arbitrary, linearly polarised lossless radiator inside that volume.
引用
收藏
页码:201 / 205
页数:5
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