DocumentCode :
1857392
Title :
Poynting´s theorem and time-harmonic radiators
Author :
Grimes, Dale M. ; Grimes, Craig A.
Author_Institution :
Pennsylvania State Univ., University Park, PA, USA
fYear :
1994
fDate :
5-12 Feb 1994
Firstpage :
313
Lastpage :
322
Abstract :
An important parameter of any antenna is the ratio of standing reactive energy stored about the antenna to the radiated power; by definition, quality factor Q is ω times that ratio. Q is often inversely proportional to the operational bandwidth of the antenna. Extensive experience and electromagnetic theory arguments based upon Q seem to agree that an efficient antenna must be about a half wavelength long in at least one dimension. But is this a general property of radiation fields, or is it due to an inadequate understanding on our part? Can the size limitations be mitigated or even bypassed? In this paper we re-examine the fundamentals of radiating fields and conclude that there is a significant special case that has not been adequately examined previously. We examine it and conclude that errors of omission are made in previous analyses, and significant improvements in the operation of small antennas may be possible. The complex Poynting vector is derived from the time-domain equations. Using it there are two types of radiation fields that have convenient solutions, and these are presented
Keywords :
antenna theory; electromagnetic field theory; loop antennas; reactive power; time-domain analysis; transmission line theory; Poynting´s theorem; TE radiation; TM radiation; complex Poynting vector; electromagnetic theory; errors; linear antennas; loop antennas; multipolar field expansion; operational bandwidth; quality factor Q; radiated power; radiating fields; radiation fields; reactive power; standing reactive energy; time-domain equations; time-harmonic radiators; transmission lines; Atomic measurements; Bandwidth; Dipole antennas; Electromagnetic radiation; Impedance; Power transmission lines; Reactive power; Time domain analysis; Transmission line theory; Vectors;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Aerospace Applications Conference, 1994. Proceedings., 1994 IEEE
Conference_Location :
Vail, CO
Print_ISBN :
0-7803-1831-5
Type :
conf
DOI :
10.1109/AERO.1994.291188
Filename :
291188
Link To Document :
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