A patch antenna surrounded by parasitic Y elements for beam scanning

This paper presents a small antenna system that realizes a scanning beam. The antenna system is composed of one fed patch element (into which a ring slot is cut), four parasitic bent Y elements, and four parasitic inverted L-shaped elements. These elements are all backed by a ground plane. It is emphasized that the center-to-center spacing between the fed patch and the parasitic bent Y elements is smaller than that in the array discussed in K. Murata et al. (2005). The direction of the radiation beam from this antenna system is varied by open-circuiting or short-circuiting the ends of the four parasitic bent Y elements to the ground plane, as in K. Murata et al., (2005). Also, note that the antenna system does not use phase shifters, which are commonly used for scanning the beam in conventional phased array antennas