| 摘要 |
Disclosed is an antenna system having an approximately omni-directional radiation pattern. The antenna system comprises an antenna comprising a plurality of columns disposed in parallel with equal spacing in a circular configuration. Each column comprises an elongated ground plane; an outwards-facing array comprising a plurality of antenna elements mounted on the ground plane iri a linear configuration parallel to the longitudinal edges of the ground plane, each antenna element comprises two feeds configured to produce orthogonally polarised radiation; a first input connected to the feeds configured for a first polarisation; and a second input connected to the feeds configured for a second, polarisation. The antenna system further comprises a feeding network comprising a first circuit network and a second circuit network. The first inputs of the columns are connected to respective outputs of the first circuit network, and the second inputs of the columns are connected to respective outputs of the second circuit network. Each circuit network is adapted to impart a phase shift to each of two inputs to the circuit network that increments between the outputs of the circuit network by a multiple of 360° divided by the number of columns.
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