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International Journal of Antennas and Propagation
Volume 2013 (2013), Article ID 608393, 8 pages
http://dx.doi.org/10.1155/2013/608393
Research Article

A Wideband Waveguide Antenna with Nearly Equal E- and H-Plane Radiation Patterns

1School of Information Science and Engineering, Southeast University, 2 Sipailou, Jiangsu, Nanjing 210096, China
2East China Research Institute of Electronic Engineering, 199 Xiangzhangdadao, Anhui, Hefei 230088, China
3Department of Electromagnetic Field and Microwave Technology, Missile Institute of Air Force Engineering University, Shanxi, Xi'an 710051, China

Received 13 October 2012; Revised 29 December 2012; Accepted 30 December 2012

Academic Editor: Tat Yeo

Copyright © 2013 Mei Qing Qi 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 novel wideband waveguide antenna with excellent performance is proposed, which is composed of a coaxial-waveguide transition and an open-ended rectangular waveguide loaded with a pair of horizontal umbrella-shaped metallic brims. The brims perpendicular to two broad walls of the waveguide are constructed to modulate the antenna to radiate nearly identical E- and H-plane radiation patterns. A wideband impedance matching performance is achieved with a fractional bandwidth of 40% through the introduction of short-stepped ladders. The antenna has the advantages of simple structure, symmetric radiation pattern, low-cross polarization, moderate back lobe, and almost constant beamwidth.