European Space Agency

Centaur - Hybrid Electro-Mechanical Scanning Satellite User Terminal Antenna



The concepts investigated in the frame of this activity are Ka-band hybrid antennae for the aeronautical segment, with a secondary target being the land-mobile segment.

The solutions are analysed and assessed with respect to the most critical parameters of mobile terminals: RF performances, steering agility on critical tracking conditions (e.g. keyhole situation), compliance with emission regulations (tracking precision, skew angle effect, polarisation purity), size/height, mass, power consumption, cost.

The best solution will be designed in detail. A demonstrator of the antenna, representative of the design, will be manufactured to proof the manufacturability of the design and will be tested to validate the most critical aspects of the design and the expected capabilities.

To conclude the results of the activity will be analysed and a plan for the development of commercial user terminals based on the designed configuration will be defined.


Several requirements are especially challenging, such as the overall dimensions, all RF aspects especially electronic pointing, and the hybrid-pointing algorithm.


The hybrid antenna approach intends to combine the best features of fully mechanical and fully electronic antennae in a hybrid compromise which offers overall advantages in terms of RF performance, size, power consumption and cost.


  1. Performance typical to a 40-60cm aperture, but with height significantly less (30cm) 
  1. Scan range comparable to fully mechanical antennae, but with better pointing speed and acceleration rates (particularly necessary for land-mobile segment) 
  1. Power consumption lower than existing fully phased arrays 

These attributes together form a unique selling proposition that will result in a successful commercialisation.


The hybrid antenna concept combines electronic and mechanical beam steering system. Aspects of the beam pointing are mechanical or electronic depending on the concept being considered. Generically, the architecture of the antennae is composed of three main parts: 

  1. Antenna apertures: including radiators, amplification, filtering and electronic beam scanning circuitry. 
  1. Mechanical platform: Structural support, actuators and mounting fixtures 

Automatic Control Unit: process attitude and/or signal information and steer the antenna beam. The ACU includes internal sensors measuring angular rotation and acceleration that maintain the pointing of the antenna beam in mobile conditions, plus it receives information from external devices, either from an IMU or signal quality information, to determine the position of the satellite. 


The plan consists of the following phases:

  1. Consolidation of Antenna Requirements and Reference Antenna
  2. Antenna Preliminary Design and Analysis
  3. Antenna Detailed Design and Analysis
  4. Demonstrator Preliminary Design and Analysis
  5. Demonstrator Detailed Design
  6. Demonstrator Manufacturing and Test
  7. Antenna Final Design Update. Lessons Learnt and Roadmap

Current status

Final preparations for the PDR have been completed


ESA Contacts

Status date

Wednesday, September 13, 2017 - 08:58