Stacked Arrangement of Convexo-Concave Antenna and Simple Rectangular Patch Antenna for Modern Communication Systems

Abstract

In the present communication, we have proposed stacked arrangement of two planar antennas. The lower patch has convexoconcave
structure and acts as driver element and the upper stacked patch is a simple rectangular patch which acts as parasitically coupled to lower patch. The size of upper patch is marginally higher than that of driver element. The two patches are separated by a thin foam substrate. This proposed antenna resonates at two frequencies which lie in the medium band (3.25 to 3.85 GHz) and upper band (5.2 to 5.85 GHz) of Wi-Max  application. The impedance bandwidths in these two bands are 19.89% and 14.42% with respect to center frequency. In addition, antenna also provides circularly polarized radiations. The axial ratio bandwidth, gain, directivity and radiation efficiency are improved than a single layer convexo-concave antenna. The radiation patterns of proposed antenna in the entire frequency range are identical in shape and directed normal to patch geometry.