Radiation Pattern Synthesis from Various Shaped Reflectors Base on PO and PTD Methods for Point-to-Multipoint Applications

This paper presents the shaped reflector antenna by using backscattering technique to achieve the completely broad-beam radiation pattern. The radiation synthesis method for shaped reflector that has to illuminate a predefined circular area are presented by using a variety of discretization of elementary geometrical functions such as, triangular, quadratic, circular, guassian, cosine, squared cosine, parabolic and hyperbolic distributions. The antenna characteristics i.e., maximum ripple level, maximum gain, and half-power beamwidth (HPBW) of the variety of shaped reflectors are analytically determined by using physical optics (PO). These shapes reflector will be discussed on merit and demerit to choose for utilization in wireless local area network (wireless LAN). The reflector which has appropriate characteristics for indoor wireless LAN in very large room will be analyzed detail by introducing the fringe wave (FW) in physical theory of diffraction (PTD). Having confirmed the validity of this approach, the X-band antenna prototype is designed and developed. The proposed antenna is tested experimentally and shows good performance. Key-Words: PO, PTD, shaped reflector, radiation pattern synthesis, broad-beam antenna, wireless LAN