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StatusOngoing
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Status date2024-11-20
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Activity Code5B.197
Starting point for this activity was the EM design of a combined Tx-Rx Ka band feed chain for user application, developed in a previous program.
This feed chain was further developed and qualified as EQM in a scalable feed cluster. Therefore, beside the RF performance, mass and dimensions were important design drivers. The feed cluster in this program consists of a waveguide panel, designed as beam forming network, carrying 16 horn-polariser assemblies.
The design of the Ka band feed chain needs to allow the application in a scalable feed cluster to be used as feed for a multi spot beam antenna. To be able to achieve narrow beam spacing and a compact feed size, the outer diameter of the feed chain was chosen to be 30mm. To achieve a good RF performance with such accommodation constraint, while fulfilling the environmental requirements was the main challenge of this program.
The small outer diameter of the feed chain allows dense packing of feed chains in an array. Coming along with minimised dimensions are advantages wrt mass and required space on the satellite compared to previous products.
The included beam forming network offers the ability of sharing apertures between neighbouring beams. With the chosen concept, a generation of seamless spot beams is achieved in one direction.
The designed Ka-band feed chain consists of a horn and a four port polariser network providing LHCP and RHCP for transmit and receive function. Tx covers 17.3GHz – 20.2GHz and Rx 27.5GHz – 30.0GHz.
The dimension and mass values are significantly reduced and enable the application for dense feed clusters.
Four feed chains are combined via the beamforming network to create a single beam. Used in a reflector antenna, the sharing of feeds allows the generation of rows of seamless spot beams in one direction. The gaps between the rows can be filled with a second antenna of the same type.
All parts of the array are designed to allow easy scaling of the feed array.
The project started with the mechanical analysis of the EM feed chain model of the previous program. Design iterations to balance RF performance and mechanical properties followed.
In parallel a waveguide panel with an integrated distribution network was designed. Both designs were performed under the constraint of scalability with respect to the number of feeds in the cluster.
After the detailed design phase all components were manufactured, integrated and tested according to the requirements.
The project is completed successfully.
