A small spiral ring antenna with the same radiation pattern as a one-wavelength loop antenna
✍ Scribed by Hideyuki Nebiya; Nozomu Hasebe; Satoshi Nagasawa
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 261 KB
- Volume
- 83
- Category
- Article
- ISSN
- 8756-6621
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✦ Synopsis
A small antenna with a size of 1/15 to 1/5 wavelength, consisting of a toroidal coil of fixed length, is proposed. The radiation characteristics of antennas with a limited range of turn numbers and pitch angles are analyzed by the conventional method and the method of moments. The conventional method is based on the assumption of a cosinusoidal current distribution along the antenna element. The results are then compared with experimental results. It is found that the method of moments with correction for the resonant frequency expresses well the characteristics of this smallsize antenna, and that fairly good agreement between the results of the conventional method and the experimental results is obtained. For the limited size range adopted in this paper, the proposed antenna offers the advantages of having the same radiation pattern as a one-wavelength loop antenna, allowing easy matching to a coaxial line, and achieving a relatively high gain despite its small size.