DocumentCode :
1487556
Title :
A curved spiral antenna above a conducting cylinder
Author :
Nakano, Hisamatsu ; Nakayama, Kazuo
Author_Institution :
Coll. of Eng., Hosei Univ., Tokyo, Japan
Volume :
47
Issue :
1
fYear :
1999
fDate :
1/1/1999 12:00:00 AM
Firstpage :
3
Lastpage :
8
Abstract :
A curved spiral antenna above a finite hollow conducting cylinder is analyzed using the method of moments. The effects of cylinder length 2H and cylinder radius rcy on the radiation characteristics of the spiral are evaluated. As 2H increases, the cross-polarization component of the radiation field in the broadside direction decreases to a constant value (approximately -18 dB). When 2H is greater than one wavelength (λ0), the input impedance of the spiral above a cylinder of radius rcy=0.25 λ0 is almost constant (250-j20 Ω) with a gain of approximately 7 dB. The spiral above a cylinder of (2H, rcy)=(2.7 λ0, 0.25 λ0) shows a 3-dB axial ratio bandwidth of approximately 23%, which is wider than a flat spiral antenna above a flat ground plane of infinite extent
Keywords :
antenna radiation patterns; electric impedance; electromagnetic wave polarisation; method of moments; spiral antennas; 3-dB axial ratio bandwidth; MoM; broadside direction; conducting cylinder; cross-polarization component; cylinder length; cylinder radius; finite hollow conducting cylinder; flat spiral antenna; gain; infinite flat ground plane; input impedance; method of moments; radiation characteristics; radiation field; Bandwidth; Current distribution; Dipole antennas; Engine cylinders; Impedance; Microstrip antenna arrays; Microstrip antennas; Mobile antennas; Moment methods; Spirals;
fLanguage :
English
Journal_Title :
Antennas and Propagation, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-926X
Type :
jour
DOI :
10.1109/8.752973
Filename :
752973
Link To Document :
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