Multi-Octave Broadband Dipole and Monopole Antennas
James L. McDonald 1, Farzin Lalezari 2, and Dejan S. Filipovi´c 1
1-Department of Electrical and Computer Engineering University of Colorado at Boulder, 2-FIRST RF Corporation
Wire monopoles have been used for over 100 years. They are inherently narrow band and typically do not operate well outside the resonance (for example, deep off-axis nulls when its length is 3/4 wavelengths). Common approaches for enhancing the bandwidth include the use of thick arms, conical feed sections, electrical/trap loading, and the use of a spherical cap. These methods are generally well known; however, very little published data regarding the combined effects are available. In this paper individual and combined broad-banding techniques are discussed. Conical feed sections are utilized for improving the input impedance of an electrically thick monopole antenna. The consistency of the radiation pattern is compared to that of a quarter-wave monopole. A parametric study is performed and an antenna is designed. The conclusions and observations are supported with finite element and method of moment numerical models. Multi-octave broadband impedance matching and radiation pattern bandwidths are obtained.
Antenna Applications Symposium
2005
September
Due to copyright restrictions articles are not available for download. They are however indexed on this site and search results will therefore correctly indicate if such terms are present in the articles.
