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 r_cy 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 r_cy=0.25 λ₀ is almost constant (250-j20 Ω) with a gain of approximately 7 dB. The spiral above a cylinder of (2H, r_cy)=(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