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A double-layer dipole array polarizer for planar antenna

1997; Wiley; Volume: 80; Issue: 11 Linguagem: Inglês

10.1002/(sici)1520-6424(199711)80

8756-6621

Hiromitsu Uchida, Kimio Sakurai, Makato Ando, N. Goto,

Advanced Antenna and Metasurface Technologies

This paper proposes a periodic dipole array with a double-layered structure as the polarizer for a planar antenna. The structure is analyzed in the spectral domain. Parameters are determined so that the transmission coefficient and the cross-polarization discrimination (XPD) are maximized for an incident circular polarized wave. As a result, theoretical values of less than 0.2 dB for the transmission loss and above 28 dB for XPD for the 11.7–12.0 Ghz band are obtained. Construction and the characteristics of the structure are described. Satisfactory characteristics were obtained, except that the transmission loss was worse by approximately 0.3 dB than the theoretical value. The spacing between the antenna and the polarizer is investigated. This is an important parameter when installing a planar antenna. When the polarizer is attached to an antenna, the characteristic is affected by mutual coupling through the higher-mode waves. It is shown theoretically that the two must be separated by 8 mm or more at 12 Ghz in order to realize the desired polarization characteristic. The designed polarizer was attached to a circular polarization radial-line slot antenna and the characteristics were examined. The result of the experiment was that an XPD larger than 20 dB was obtained with little loss of gain. Results for the installation distance and angle were confirmed. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(11): 86–97, 1997