The Role of Reactive Energy in the Radiation by a Dipole Antenna

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The spatio-temporal distribution of the near field around an antenna is of fundamental importance in understanding its radiative properties, since it can affect the radiated power flow emitted by the device. In this work, we consider the simplest case of a harmonic point dipole antenna activated at some point in time, and study the distribution of the energy flow velocity and reactive energy in space and time. We discuss how the reactive energy building up around the radiator affects quite strongly the flow of energy in the vicinity of the dipole, while in the far field, the expected radiation features are restored. The reactive energy in the near field decelerates or even inverts the overall energy flow, resulting in partial standing waves near the feed. We also investigate the transient response of the stored reactive energy and identify the convergence to steady state, which is demonstrated through time-averaged quantities. Our results shed interesting observations on the radiation properties of antennas in their near field, as time progresses.

Original languageEnglish
Article number7111231
Pages (from-to)3736-3741
Number of pages6
JournalIEEE Transactions on Antennas and Propagation
Volume63
Issue number8
DOIs
Publication statusPublished - Aug 1 2015
Externally publishedYes

Fingerprint

dipole antennas
Dipole antennas
Antennas
Radiation
Radiators
radiation
Transient analysis
Flow velocity
near fields
energy
antennas
temporal distribution
transient response
radiators
standing waves
far fields
flow velocity
dipoles
harmonics

Keywords

  • Dipole antennas
  • energy flow velocity
  • Poynting vector
  • reactive energy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

The Role of Reactive Energy in the Radiation by a Dipole Antenna. / Valagiannopoulos, Constantinos A.; Alu, Andrea.

In: IEEE Transactions on Antennas and Propagation, Vol. 63, No. 8, 7111231, 01.08.2015, p. 3736-3741.

Research output: Contribution to journalArticle

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