Bifilar Helical Array Antenna Using Overlapped Structure

Ryo YAMAGUCHI  Noriyoshi TERADA  Yoshio EBINE  Yoshihide YAMADA 

Publication
B - Abstracts of IEICE TRANSACTIONS on Communications (Japanese Edition)  Vol.J91-B  No.9  pp.998-1007
Publication Date: 2008/09/01
Online ISSN: 1881-0209
Print ISSN: 1344-4697
Type of Manuscript: Special Section PAPER (Special Issue on Emerging Technologies of Antennas and Propagation Supporting High-speed Wireless Communications)
Category: 
Keyword: 
mobile satellite communication,  vehicle antenna,  helical antenna,  array,  overlap,  impedance matching, 

Full Text(in Japanese): PDF(689.9KB)

Summary: 
A helical antenna is useful for vehicle antenna of satellite communication system because it has circularly polarization, and an omni-directional beam in the horizontal plane. However, it is impossible to have wide coverage by using only one element because the beam direction for up-link differs from that for down-link. In this paper, we have proposed a new liner array helical antenna whose elements overlap each other without contact. This array antenna is able to have any distance between the feed points regardless of the length of elements. We show the optimal feed distance, length of antenna and feed phase shift using this method. Furthermore, we have proposed a wide band impedance matching method by using a parasitic ring element.