Theory and experiment of a circularly polarized conical beam spherical slot array antenna

The authors proposed a circularly polarized conical beam spherical slot array antenna for applications of low bit rate or low gain/temperature ratio (G/T) land mobile satellite communication and broadcasting services in addition to wireless local area network base stations (see Krairiksh, M. et al., Int. J. Electronics, vol.86, no.7, p.815-23, 1999). The advantage of this antenna is that the structure is simple and suitable for mass production and the feeding structure is also simple. From preliminary results, the radiation pattern appears to be a conical beam (see Phongcharoenpanich, C. et al., IEICE Trans. Electronics, vol.E82-C, no.7, p.1242-7, 1999). This paper presents the theory and experiment of a circularly polarized conical beam spherical slot array antenna. The theoretical result is carried out by means of the method of moments. With the aid of the dyadic Green´s function, the integral equations of the unknown currents are solved by using entire domain basis functions and Galerkin´s method. The theoretical results of the radiation pattern, elevation angle and directivity, input impedance and axial ratio are illustrated. The experimental results agreed satisfactorily with the theoretical ones.