Qinetiq Limited

Quintel Technology Limited

Duncan Alan Wynn

Philip Edward Haskell

Louis David Thomas

An antenna system having a transmissive surface and an antenna arranged to transmit or receive radiation through the transmissive surface via a radiation lobe of the antenna. The system further includes a displacing arrangement to displace the radiation lobe of the antenna relative to the transmissive surface as necessary so as to reduce a change in one or more characteristics of the radiation on passing through the transmissive surface. A corresponding method is additionally described.

Antenna system compensating a change in radiation characteristics

An antenna system for sharing of operation employs contiguous transmit frequencies. Transmit frequencies are separated into non-contiguous sub-groups isolated from one another by filters(+) and(&#x2212;) associated with positive and negative polarisation. Received frequencies are filtered and split into five signals for input to base station receive ports. Non-contiguous transmit frequency sub-groups are combined by a quadrature hybridand pass with 90 degree relative phase shift to mutually orthogonal antenna stack ports P(+) and P(&#x2212;) associated with orthogonally polarised sets of antenna elements AS(+) and AS(&#x2212;): the ports P(+) and P(&#x2212;) are isolated from one another by the hybrid. The 90 degree phase shift results in one transmit subgroup being radiated with left hand circular polarisation and the other transmit subgroup being radiated with right hand circular polarisation. Changing the relative phase shift changes the radiated polarisation to linear or elliptical, and signal amplitude weighting provides control of antenna beam polarisation direction.

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Malvern, United Kingdom

Duncan Alan Wynn