A tangential electric field equation for a wire antenna on a dielectric half-space of relative permittivity εr is formulated using a finite-difference technique. This equation involves only single-integral calculations and is used to obtain the current distribution of a square spiral antenna. The validity of the current obtained is checked by FD-TD analysis. Based on the current distribution obtained, the radiation characteristics of the spiral are evaluated. It is found that the gain in the dielectric material is larger than that in free space, with a ratio of εr1.5 in the broadside directions. As εr increases, the circularly polarised radiation region bounded by the critical angles in the dielectric becomes narrower and the resistance value of the input impedance becomes lower.
|ジャーナル||IEE Proceedings: Microwaves, Antennas and Propagation|
|出版物ステータス||Published - 1998|
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering