Multifilar Hemispherical Helical Antennas

Simple item page
dc.contributor.authorClark, Jeffrey R.en
dc.contributor.committeechairSafaai-Jazi, Ahmaden
dc.contributor.committeememberDavis, William A.en
dc.contributor.committeememberBesieris, Ioannis M.en
dc.contributor.departmentElectrical and Computer Engineeringen
dc.date.accessioned2014-03-14T20:49:18Zen
dc.date.adate2003-12-16en
dc.date.available2014-03-14T20:49:18Zen
dc.date.issued2003-10-31en
dc.date.rdate2004-12-16en
dc.date.sdate2003-12-11en
dc.description.abstractHelices are broadband antennas that provide moderate gain, largely real input impedance and circular polarization when operating in the axial mode regime. A modified form of the helix, the spherical helix, has been shown to yield similar polarization and gain characteristics over a narrow bandwidth but a much larger beamwidth. This investigation examines multifilar hemispherical helices and produces two specific designs with some desirable radiation characteristics. The side-fed quadrifilar helix and the top-fed bifilar helix are the new hemispherical designs which are studied in detail both numerically and experimentally. The Numerical Electromagnetics Code 4 is used to analyze the radiation characteristics of the proposed multifilar hemispherical helices. Directivity, E- and H-plane radiation patterns, axial ratio and input impedance of a few example designs are calculated. Measurements, taken in the anechoic chamber at the Virginia Tech antenna range, generally confirmed the simulation results. It is shown that the bifilar hemispherical helix provides a flat gain curve over the measured bandwidth (~14%) and generally elliptical polarization with near circular polarization in limited case.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-12112003-095406en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12112003-095406/en
dc.identifier.urihttp://hdl.handle.net/10919/36060en
dc.publisherVirginia Techen
dc.relation.haspartJRClarkThesis03.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectquadrifilar helixen
dc.subjecthelical antennasen
dc.subjectmultifilar helicesen
dc.subjectNEC-4en
dc.titleMultifilar Hemispherical Helical Antennasen
dc.typeThesisen
thesis.degree.disciplineElectrical and Computer Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
JRClarkThesis03.pdf
Size:
1.07 MB
Format:
Adobe Portable Document Format
Download

Collections

Masters Theses