Enabling & Support

ESA: compact orthomode transducer device

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ESA / Enabling & Support / Space Engineering & Technology
558 - Abstract:
The European Space Agency has developed a compact orthomode transducer device. This technology can be used in terrestrial point to point VSAT communications. License agreement collaborations are sought.

Description of the offer

The present invention relates to an orthomode transducer (OMT) device. The OMT is an antenna-feed waveguide component able to discriminate linear polarizations. More especially it is capable of dividing the Horizontal from the Vertical polarization and, in reverse direction, capable of combining them.

The offered technology relates to a compact low mass and cost-efficient to manufacture OMT. The component looks similar to the well-known septum polarizer. However, contrary to this one, the compact OMT has a 180 degrees phase shifter rotated by 45 degrees along the propagation axis. These two modifications transform the septum polarizer (that can only be used for Circular Polarization) in a highly compact dual linear polarization OMT.

Thus, no resonant structures such as irises or metallic slots are required to split orthogonal polarizations. As a consequence, the compact OMT device has a high power handling and is cost-efficient to manufacture. Furthermore, the waveguide accesses of the compact OMT are perfectly parallel enabling an easy and very compact assembly of multi feed arrays in contrast to conventional OMT devices with perpendicular waveguide accesses.

Orthomode transducer (OMT) device
Orthomode transducer (OMT) device

Due to the geometrical symmetry of the component, the vertical and horizontal polarization paths are identical therefore; the performances (insertion loss, cross-polar, return loss) of the compact OMT are the same regardless of the polarization. The compact OMT is the only known solution to have this feature. This can be very interesting for applications requiring the same electrical path for both polarizations like some BFNs and correlation receivers.

The compact OMT is simple to manufacture. In fact, the very same techniques used to machine septum polarizers can be used (standard milling, wire or spark erosion in aluminium).

The compact OMT offers a minimum size in X and Y axis (being Z the propagation axis). In addition, the device is also compact in the Z axis.

The compact OMT is a low mass solution. The component is made by a square waveguide with a stepped metallic septum in the middle, which clearly results in a very low mass device. In addition, the waveguide interface is completely parallel, saving waveguide twists and bends which not only increase the mass but degrade the insertion and return loss as well.

Innovations and advantages of the offer:

The offered technology is an improvement over actual orthomode transducer devices due to its compact design, low mass and cost-efficient to manufacture. In addition, is an excellent candidate for high-power RF applications.

Domain of Application:

This technology could be used in terrestrial point to point VSAT communications. In general, it could be used in any antena feed requiring a low loss, high power, compact and/or low mass dual-linear OMT.

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