Two Resistors Loaded Ultra-Wideband Small Spiral Antenna

Satoshi YAMAGUCHI  Hiroaki MIYASHITA  Kazushi NISHIZAWA  Kenichi KAKIZAKI  Shigeru MAKINO 

Publication
B - Abstracts of IEICE TRANSACTIONS on Communications (Japanese Edition)  Vol.J90-B  No.9  pp.830-836
Publication Date: 2007/09/01
Online ISSN: 1881-0209
Print ISSN: 1344-4697
Type of Manuscript: Special Section PAPER (Special Issue on Antenna and Propagation Technologies for realizing the ubiquitous network society)
Category: 
Keyword: 
wideband antenna,  spiral antenna,  resistor,  cavity,  FDTD, 

Full Text(in Japanese): PDF(723.6KB)

Summary: 
Spiral antennas have ultra-wideband characteristics such as a nearly constant input impedance, antenna gain, and low axial ratio. However, when reflectors such as conducting planes or cavities are used, their performances are degraded due to reflections from the end of these spiral arms. In particular, this effect is remarkable at low frequencies where these antennas become small in comparison to their wavelengths. In this paper, we propose a new type of a small spiral antenna that has a pair of resistors and verify its ultra-wideband characteristics.