The directivity of a compact antenna: an unforgettable figure of merit
Author
Ziolkowski, Richard W.
Affiliation
Univ Arizona, Dept Elect & Comp EngnIssue Date
2017-10-11Keywords
DirectivityElectrically small antennas
Huygens source
Metamaterial-inspired antennas
Patch antennas
Metadata
Show full item recordPublisher
EDP SCIENCES S ACitation
The directivity of a compact antenna: an unforgettable figure of merit 2017, 4:7 EPJ Applied MetamaterialsJournal
EPJ Applied MetamaterialsRights
© R.W. Ziolkowski, published by EDP Sciences, 2017. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
When an electrically small antenna is conceived, designed, simulated, and tested, the main emphasis is usually placed immediately on its impedance bandwidth and radiation efficiency. All too often it is assumed that its directivity will only be that of a Hertzian dipole and, hence, its directivity becomes a minor consideration. This is particularly true if such a compact antenna radiates in the presence of a large ground plane. Attention is typically focused on the radiator and its size, while the ground plane is forgotten. This has become a too frequent occurrence when antennas, such as patch antennas that have been augmented with metamaterial structures, are explored. In this paper, it is demonstrated that while the ground plane has little impact on the resonance frequency and impedance bandwidth of patch antennas or metamaterial-inspired three-dimensional magnetic EZ antennas, it has a huge impact on their directivity performance. Moreover, it is demonstrated that with both a metamaterial-inspired two-element array and a related Huygens dipole antenna, one can achieve broadside-radiating electrically small systems that have high directivities. Several common and original designs are used to highlight these issues and to emphasize why a fundamental figure of merit such as directivity should never be overlooked.Note
Open Access Journal.ISSN
2272-2394Version
Final published versionAdditional Links
http://epjam.edp-open.org/10.1051/epjam/2017006ae974a485f413a2113503eed53cd6c53
10.1051/epjam/2017006