Abstract
This article attempts to clarify the concept of
quality factor (Q) in connection with ideal radiating
systems. Three different aspects are covered: Q (i) as a
relation between the stored energy and radiated power in
the modes corresponding to a given radiation field
outside a spherical source volume, (ii) as a function of
the measurable impedance or admittance and (iii) as a
function of the bandwidth of a resonated system. The
first approach yields a theoretical lower limit: the
larger the sphere, the more inconceivable in practice.
The second approach approximates the observable stored
energy and incorporates the minimum energy necessary for
the transport of energy from the feed point to the region
outside the circumscribing sphere. The third method
yields the antenna Q on condition that the input
impedance corresponds to a single resonance phenomena.
Original language | English |
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Pages (from-to) | 189-195 |
Journal | Electrical Engineering |
Volume | 84 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2002 |
MoE publication type | A1 Journal article-refereed |
Keywords
- quality factor
- antennas
- stored energy
- bandwidth
- input inpedance