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International Journal of Antennas and Propagation
Volume 2014 (2014), Article ID 102362, 7 pages
http://dx.doi.org/10.1155/2014/102362
Research Article

Yagi Array of Microstrip Quarter-Wave Patch Antennas with Microstrip Lines Coupling

1Department of Electronics and Communication Engineering, Sun Yat-sen University, Guangzhou 510006, China
2SYSU-CMU Shunde International Joint Research Institute, Shunde 528300, China

Received 28 March 2014; Revised 29 June 2014; Accepted 14 July 2014; Published 22 July 2014

Academic Editor: Z. N. Chen

Copyright © 2014 Juhua Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A new kind of Yagi array of quarter-wave patch antennas is presented. The Yagi array has a low profile, a wide bandwidth, and a high gain. A main beam close to endfire is produced, with a vertical polarization in the horizontal plane. A set of microstrip lines are introduced between the driven element and the first director element to enhance the coupling between them, and therefore the bandwidth could be increased and the back lobes could be suppressed. Measured results show that the Yagi array with 4 elements generates a peak gain of about 9.7 dBi, a front-to-back ratio higher than 10 dB, and a 10 dB return loss band from 4.68 GHz to 5.24 GHz, with a profile of 1.5 mm and an overall size of 80 × 100 mm2. An increase of the number of director elements would enhance the gain and have the main beam pointing closer to endfire.