Circular OMT for complete C-Band (TX: 3.625 - 4.200GHz; RX: 5.850 - 6.425 GHz)

Status date

A C-Band OMT able to cover the complete TX & RX bands in dual circular polarization was developed. High power capability and low mass and volume were the driver parameters for the design. An EQM was manufactured and tested to show the performances initially obtained by design.

The goal was to develop a new concept for C-Band OMT capable of covering the complete TX and RX bands in dual circular polarization. The design is suited for new generation of platforms with high power capability and increasing number of channels. On the other hand, the unit exhibits low volume and mass.


The key parameters which drove the design were: high power capabilities, excellent electrical behaviour and minimum volume and mass.


The expected main benefit is the possibility for a customer to have an excellent polarizer covering the full TX&RX C-Bands, with a minimum volume. The polarizer could feed the circular polarization of a corrugated horn composing a complete feed. The corrugated horn could also be designed and manufactured by Rymsa, since that is the core of our business. The need of high power usually demanded for that band, is also taken into account not only at design level but also in the test campaign.

It is also worth pointing out the gain, from an industrial point of view, of having a generic design, even for applications not requiring operating over the full C-band.


The proposed concept is a self-diplexing junction (OMT-J) with filters attached to it. The RX path is composed by a septum, allowing injecting dual polarized RX signals into the OMT-J. The TX path is based on a branching structure of four arms merging from a turnstile junction to the OMT-J, everything around the RX chain components.

click for larger image


The design phase covered the requirements consolidation, concept selection and detailed design for the C-Band OMT.

The first task was the review of currently existing requirements for C-Band Feeders to derive the requirements for the C-Band OMTs and reach to a consolidated Requirements Document.

Afterwards, the possible potential solutions complying with the established requirements, based on RYMSA heritage, were identified. The set of possible candidate configurations were analysed in order to assess their performances and its level of compliance with the requirements, special efforts were focused on optimising mass. This task was concluded with a Technical Meeting, where the most suitable OMT design was selected to continue with the detailed design.

The last part of the design phase addressed the detailed design of the OMT. This detailed design covered the completion of the electrical design and specially the mechanical design and industrialization aspects. At the end of this task the selected configuration was prototyped (EQM). The ICD, Manufacturing Drawings, Assembly Drawings, Materials, Parts and Processes Lists and Test Plan for this EQM were also issued during this task.

This phase was completed after successful CDR, and the EQM manufacturing was authorised.

Manufacture & Qualification phase: The main objective was to build and test an EQM to demonstrate the proposed design complied to the specifications.

The EQM was tested to qualification levels and duration according to the relevant specifications. The test started after closure of the Test Readiness Review (TRR). After successful completion of the test campaign, a Test Review Board (TRB) was held, where the compliance status to requirement were addressed.

The Qualification phase has been finished after successful closure of the TRB. The design is considered qualified and ready for flight model manufacture.

Current status

The qualification test campaign has been successfully finalized.