Fan-beam forming for a linear antenna with exponential-tapered amplitude distribution
| Autor: | Masataka Ohtsuka, Yoshihiko Konishi, Makoto Matsunaga, Shuji Urasaki |
|---|---|
| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | Electronics and Communications in Japan (Part I: Communications). 79:69-78 |
| ISSN: | 1520-6424 8756-6621 |
| DOI: | 10.1002/ecja.4410791008 |
| Popis: | As a fan-beam forming method for a line source having an exponential-tapered amplitude distribution simulating the linear array antenna or a linear antenna with a traveling-wave feed such as in the multifilar helical antenna, this paper investigates a method in which the entire source is divided into n : 1 and the excitation phase in the 1/(n + 1) portion is π shifted. First, the fan-beam forming method is studied analytically for a linear source with an exponential-tapered amplitude distribution so that the equation needed for realizing a fan beam is derived. Next, in the case where a fan beam is formed for the determined coverage angle (angle θ = 30–60°) from the zenith, the relationship between the total length LT of the source and the coverage gain is studied. It is shown that the coverage gain can be improved by forming a fan beam. It is shown also that there exists an optimum value of the total length of the source maximizing the coverage gain for a given coverage area. Further, by using a bifilar helical antenna, a fan-beam forming experiment is carried out. It is confirmed that a fan beam close to the computed value can be formed and the coverage gain can be improved although there exists asymmetry in the measured radiation pattern. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|