Investigation of a New Class of Low-Profile Multi-Layer Printed Antennas

Abstract

Abstract : This progress report outlines our research efforts on modeling, analyses and optimization of multi-layered printed antennas for high gain applications. Our research during this interim period has resulted in progress in the following four areas. (1) Performance analysis of a linear array of Yagi-like printed sub-array antennas. Effects of mutual couplings on gain and pattern degradation of previously optimized Yagi-like structures are investigated for various array configurations. (2) Development of an electromagnetic optimization engine based on Method of Moments and Evolutionary Programming for design of multi-layer printed antennas. During this interim period, this code has been extended to include printed patch antennas of arbitrary shapes. In addition, the use of various mutation operators to speed-up the optimization process has been investigated in details where it has been found that a Cauchy mutation operator can significantly speed-up the optimal design of antenna structures. (3) Design of circularly polarized (CP) high gain multilayer antenna elements. The design feasibility of a high gain CP patch antenna is demonstrated for MSAT application where a gain of more than 11.6 dBi with an axial ratio of less than 1.1 dB is obtained. (4) Theoretical investigation of Gain Enhancement methods for the Yagi-like antennas printed in a multi-layer uniaxial anisotropic medium. It is shown that by a proper selection of anisotropy ratios and thickness of the layers, it is' possible to obtain two high gain beams at theta(sub E) and theta(sub H) in E and H planes, respectively. In addition, the physics of these high gain fields are investigated in terms of the leaky-wave radiation.