Abstract
A novel unbalanced feed system, which achieves quasi-antiphase excitation without a balun circuit, is proposed for a two-wire spiral antenna backed by a conducting plane reflector. An inner spiral-wire end is fed from a coaxial line and the other inner spiral-wire end is short-circuited to the reflector. The antenna is analyzed using the method of moments. The radiation characteristics are found to be comparable to those of a conventional spiral antenna with antiphase excitation. The frequency bandwidth for a 3-dB axial-ratio criterion is 18% (20% for antiphase excitation), with a gain of approximately 8 dBi (8 dBi for antiphase excitation). The input impedance is almost constant at 170 - j30 ohms.
| Original language | English |
|---|---|
| Pages (from-to) | 1-9 |
| Number of pages | 9 |
| Journal | Electronics and Communications in Japan, Part I: Communications (English translation of Denshi Tsushin Gakkai Ronbunshi) |
| Volume | 86 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 2003 Apr |
| Externally published | Yes |
Keywords
- Balun
- Circularly polarized antenna
- Method of moments
- Spiral antenna
- Wideband antenna
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering