Radiation and Energy Storage Modal Analysis of Dipole Antennas

S. S.Y. Cain (Presenting Author), E. Wilken-Resman, J. T. Bernhard

Abstract

Here, the radiation and energy storage modes of a planar folded dipole antenna and a planar strip dipole antenna are considered. The modes of these structures are analyzed over a large frequency range––relative to the resonant bandwidth––in order to capture their frequency dependence. Of particular interest is the modal transition from the antennas being electrically small to electrically resonant. In the case of the folded dipole antenna, its radiation pattern changes dramatically in these limits. Specifically, the antenna transitions from behaving like a small loop to radiating in a dipole-like fashion, thus changing the plane of maximum directivity. This analysis provides quantitative insight about the surface currents responsible for the radiation of these antennas and is additionally visually intuitive.