Summary
International Symposium on Antennas and Propagation
2008
Session Number:2C10
Session:
Number:2C10-1
Effect of Pin Radius on the Radiation Characteristics of Patch Antennas with Pin Arrays
Tae-Young Kim, Woo-Ram Lee, Boo-Gyoun Kim, Jong-Dug Shin,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
Microstrip patch antennas have become one of the most popular antennas since they have several merits such as low profile, light weight, easy integration with microwave integrated circuits, and low fabrication cost [1]. The high-index substrates which allow smaller footprint make microstrip antennas compatible with both active and passive devices for monolithic microwave integrated circuits (MMIC) and antenna applications [2]. To obtain high gain and wide bandwidth, electrically thick substrates need to be used. The increase in substrate thickness, however, tends to increase surface waves and radiation in horizontal directions so that substantial amount of power leaks into the substrate. This leads to enhance the mutual coupling between radiating elements, which results in the increase of both the sidelobe level and the cross-polarization level. Multiple-Input Multiple-Output (MIMO) systems of mobile terminals require miniaturized antennas and very low mutual coupling. Therefore, various techniques have been proposed to reduce the radiation in horizontal directions and the surface-wave. These include grooving the dielectric [3], optimizing the antenna dimensions [4, 5], and covering the patch by additional dielectric layers [6]. In Ref. [7], an array of shorting pins between the patch and the ground has been proposed for the inductive currents in the pins and the capacitive polarization currents to cancel out against each other. In this paper, we investigate the effect of pin radius on the radiation characteristics of the patch antennas with pin arrays by experiment and by simulation using HFSS (High Frequency Structure Simulator). In section 2, design parameters used for three different types of patch antennas are given. Simulation and experimental results on the radiation characteristics are obtained and compared in section 3. Finally, section 4 concludes the paper.