Radiation properties of shaped beam antenna using radial line microstrip array

In the fabrication of a large-scale multi-element planar array, reduction of the feeding loss is important for realization of high-efficiency performance. An array antenna fed by a radial line has been investigated by many researchers, because it has high-efficiency performance. This paper presents a basic design technique of the shaped beam antenna fed by a low-loss radial waveguide. In order to check the performance of this antenna, some planar arrays were constructed and tested at the SHF-band. As a result of experiments, satisfactory performance was achieved in both radiation pattern and directivity gain.