Summary
International Symposium on Antennas and Propagation
2008
Session Number:4C33
Session:
Number:4C33-1
Multilayered Cone-Based High Directivity Antenna Designs
Bin Li, Kuei-Jen Lee, Hsi-Tseng Chou,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
As the wireless communication develops rapidly in recent years, more wireless equipment appears, and applications of circularly polarized (CP) antennas are widely used in the wireless communications [1]. Unless the antenna is used only for point-to-point communications, where the CP performance at the boresite direction is of major concern, it is desirable to design the antenna structure that radiates fields with an as wide beamwidth of a good CP as possible, which potentially provides better reception performances such as in the applications of global positioning system (GPS) where a single antenna is used to receive signals from various satellites in different angular locations. Such examples can be easily found in the satellite communications [2]. Although in many antenna designs, such as using cross-dipoles, a good CP can be obtained in the antenna’s boresite direction, the polarization discrimination of TE and TM modes grows while the angle of incident waves increased[3] with respect to the antenna’s boresite. That means more signal amplifications in the system are compulsory which will increase the cost accordingly. Directivity performance is a key characters for long-haul wireless signal transmission, in order to improve the efficiency of antenna and keep the polarization discrimination at a lowest level in a wide range of angular region, we introduce a compensation method using multilayer cone-based which can greatly improve the directivity of a ordinary transmitter without involve any discriminations. The cone-based multilayered structure can be regarded as one-dimension (1D) photonic crystals. The concepts of the 1D photonic crystals were first brought forward by E. Yablonovitch and S.John[4]. Photonic crystals are periodically structured using dielectric materials that can be recognized as multilayer films. If the structures show a periodicity in the range of the wavelength of the light, interferences appear which affect the propagation of light in these materials strongly and allow the energy re-distributing in the angular space. The 1D photonic crystals have been shown a wide range of applications, such as the area of laser, glass fibers and pigments, also photonic crystal can be used in the newly emerged area of integrate optics [5] and sensing [6].