Contents I. Introduction
Recently, for antenna designs in many wireless communications systems, stringent requirements on antenna's impedance bandwidth and physical size are required. For achieving a low-profile antenna having monopole-like radiation patterns, a monopolar wire-patch antenna has been reported [1]. This antenna consists of a wire monopole, top-loaded with a square patch and two ground wires connected between the loading square
Geometry of the proposed wide-band monopolar plate-patch antenna.
patch and the antenna's ground plane. With such a structure, this antenna can work like a monopole, but with an antenna height much less than a quarter wavelength of the center operating frequency. However, the impedance bandwidth obtained for the wire-patch antenna is only about 3%, which is usually too narrow to comply with the requirements of recent wireless communications applications. To enhance the impedance bandwidth, we propose in this paper, a new design of a monopolar plate-patch antenna. By replacing the wire monopole and two ground wires in the antenna reported in [1], with a planar rectangular monopole [2]and two ground rectangular plates, the proposed antenna can also have a monopolar radiation pattern, and moreover, a much enhanced impedance bandwidth can also be obtained. Details of the proposed antenna and experimental results of constructed prototypes are presented and discussed.