Open AccessEffects of loss on the determination of antenna energy and Q
Author(s) -
Thal Herbert L.
Publication year - 2017
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2015.0436
Subject(s) - lossy compression , lossless compression , antenna (radio) , dissipation , reflection coefficient , physics , energy (signal processing) , reflection (computer programming) , excitation , mathematical analysis , radiation , acoustics , computational physics , optics , mathematics , computer science , telecommunications , algorithm , statistics , quantum mechanics , data compression , thermodynamics , programming language
Expressions for the stored energy and Q factor of an antenna in terms of its radiated spherical modes and reflection coefficient have been extended to include the effects of loss. Three variations are given for excitation by matched, voltage, or current generators, and the importance of the proper phase reference for the radiated fields is emphasised. Two low‐ Q , self‐resonant spherical antennas are used to illustrate the application of the energy formulae with and without loss. The results for these examples are validated by direct integration of the electric energy and by self‐consistency of the radiation and dissipation terms. Approximation equations appropriate for processing experimental data are derived, and their predictions are compared with the actual Q ’s for the examples. Estimates of the lossless Q ’s are determined from the lossy data.