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International Journal of Antennas and Propagation
Volume 2016, Article ID 4825924, 8 pages
Research Article

Waveguide Slot Array Antenna with a Hybrid-Phase Feed for Grating Lobe Reduction

1School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
2PGM Center, Hanwha Thales, Yongin 449-885, Republic of Korea
3Agency for Defense Development, Daejeon 305-600, Republic of Korea

Received 26 November 2015; Revised 22 January 2016; Accepted 24 January 2016

Academic Editor: Safieddin Safavi-Naeini

Copyright © 2016 Son Trinh-Van 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.


The design of a 112-element millimeter-wave waveguide slot array antenna to reduce the grating lobe level is presented. A hybrid-phase feeding technique combining a cophase feed and an alternating-phase feed is applied to facilitate the suppression of grating lobes. In addition, a stepped feed waveguide and offset coupling slots aligned in a line are employed to realize a tapered aperture distribution. As a result, grating lobe suppression of 8.1 dB was achieved on the diagonal planes compared to a conventional alternating-phase-fed waveguide slot array antenna. A prototype of the proposed antenna was fabricated and measured. The measured results show that the proposed antenna exhibits a −15 dB reflection bandwidth of 3.4 and an average realized gain of 26.72 dBi within the measured frequency range. Good agreement between the simulated and measured radiation patterns is also observed.