Remote sensing is a core technology for Earth observation (EO). The resolution of new instruments and the increasing number of missions are pushing the data rates of new EO missions. The majority of current ground stations operate at S-, X- and Ka-bands. However, Ka-band is becoming very attractive to sustain higher data rates and for better spatial resolutions. Existing ground stations use two different feeds for beam width modulation, one combined with a single/dual-reflector geometry and one separated from the reflector for the narrow and wide beam, respectively. This approach is particularly relevant for Safran's products with large diameters (e.g. 11.50m, 13.5m), especially for Ka-band telemetry. Antenna size, operations, and tracking techniques are large drivers in the overall ground station cost and performance. Innovative design-to-cost solutions integrating self-tracking functionality are key for large Ka-band antennas for future missions. The main objective of this activity is to avoid redundant feeds, leading to significant cost and mass savings. In addition, frequency and polarization agility may be introduced to define competitive products for future missions with new or improved functionalities. The proposed dual-reflector configuration shown in the figure fulfills this goal by integrating a sub-wavelength textured intelligent electromagnetic surface over the sub-reflector (e.g. a frequency or polarization selective surface). A passive design can be used to introduce new filtering functionalities not achievable with a standard guided filter. This functionality may also be inserted in the form of a radome at the aperture of the feed to mitigate inter-system interference. Alternatively, a polarization selective design can be used to provide beam width adjustment for tracking purposes. A second step in the development to bring further innovation is to introduce a form of reconfigurability, either with some mechanisms or electronic components.
