Open AccessAntenna Q calculation using radiated modes and reflection coefficient
Author(s) -
Thal Herbert L.
Publication year - 2015
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.2014.0219
Subject(s) - bracket , antenna (radio) , reflection (computer programming) , reflection coefficient , value (mathematics) , mathematics , mathematical analysis , computer science , electronic engineering , physics , engineering , optics , statistics , telecommunications , structural engineering , programming language
Optimisation techniques are currently being used to design antennas with Q values close to theoretical limits. In order to evaluate how closely these designs approach the limits, it is necessary to calculate their Q s from measured or simulated data. Many standard techniques are accurate for large Q s, but yield values significantly below the actual Q for low Q cases. In this study, equations are derived to bracket the actual value of Q , and the issues involved in attempting to determine an exact value are discussed. Both time‐averaged and time‐varying energies are considered. The derivations and conclusions are different from those previously published. Data from electromagnetic simulations of design examples are used to illustrate.