A new design of horizontally polarizedand dual-polarized uniplanar conical beam antennas for HIPERLAN |
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Authors: | McEwan N.J. Abd-Alhameed R.A. Ibrahim E.M. Excell P.S. Gardiner J.G. |
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Affiliation: | Dept. of Electron. & Electr. Eng., Univ. of Bradford, UK; |
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Abstract: | It is shown that a conical beam 5.2-GHz antenna suitable for HIPERLAN application, but working in horizontal polarization, can be realized as a group of microstrip patch radiators in a ring formation. Layouts with three and four patches are described, and radiation patterns are found to agree well with predictions from a simple array model. The three-patch form is smaller and gives a closer approximation to an azimuth-independent pattern. Patterns are very similar to those achieved in vertical polarization with previously reported disk antenna realizations, giving peak radiation at about 50/spl deg/ elevation. Two methods of impedance matching are found to give satisfactory results. A dual-polarized conical-beam microstrip antenna, with a strictly uniplanar conductor pattern, is also presented and realized as an array of three square patches whose corners meet a central feed point. For the second polarization, the antenna functions as a series fed array. Fairly good conical beam patterns have been obtained, though only moderate polarization purity appears to be obtainable from three-element arrays. |
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