Cobham Technical Services designs and supplies a wide-range of high-performance feed chains and feed components. Cobham's expertise includes multi-band feeds and complex tracking sub-systems based on monopulse or electronic lobe switching configurations.
A critical component in any reflector antenna is the feed chain, its complexity being dependent on the number of functions that it has to provide. In its basic form, a feed chain consists of a corrugated horn which illuminates a reflector, a polariser that converts linear polarisations into circular and vice versa and an orthogonal mode transducer (OMT). An OMT is a waveguide component, generally a three-port device, that allows simultaneous reception and transmission of vertically and horizontally polarized signals. The input port is typically a circular waveguide. The two output ports are rectangular waveguides.
The radiation performance of the corrugated horn is of major importance. It must be able to propagate communication channels without exhibiting any unwanted reflections or mode conversion; a matching section is also required to realise a good overall VSWR performance. Sophisticated in-house computer software employing accurate mode matching techniques is available at Cobham Technical Services for feed horn design for applications in any frequency band. Similar software is used for the design of other feed chain components including polarisers, orthogonal mode transducers and filters.
Tracking feed systems
For applications where it is necessary to ensure accurate pointing of the antenna towards the satellite, Cobham is able to supply one of a number of antenna tracking solutions. For high tracking sensitivity, which might be required for Tracking, Telemetry and Control (TT&C) applications, Cobham has provided monopulse systems employing higher order waveguide modes. Where it is a requirement to maintain a high data rate communications link in a highly dynamic environment, Cobham has a novel electronic beamsquint tracking system which offers high tracking sensitivity without the need for a high cost tracking receiver.
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C and Ku Band feed chain for a
Cassegrain antenna | | 20/30 GHz Feed chain for
single offset reflector |
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20/30 GHz Feed chain for
Cassegrain antenna | | Deep Space Tx/Rx Ka
Feed chain |
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20/44 GHz Feed chain for
offset reflector | | 4/6 GHz Feed chain for
Cassegrain antenna |