A low-frequency and wide-band reflector antenna feed for future earth observation radiometers

Design and breadboard a low frequency, wide-bandwidth antenna feed with compact dimensions, highly stable phase centre and low sidelobes 

Future low frequency radiometric earth observation (EO) missions, as an example the Earth Explorer 10 (EE10) candidate mission ?cryorad?, have the challenge of realising compact low-frequency and wideband reflector antenna feeds with a high RF performance (e.g. Sidelobes and feed aperture efficiency). The scientific potential for sea ice thickness, ice sheet and ice shelf temperature profiles investigations by low-frequency radiometers, was judged high by the ACEO in the case of cryorad. However, the proposed corrugated feed of the large deployable reflector antenna including its feedchain with an Orthomode-Transducer (OMT) was judged infeasible due to large dimensions, i.e. More than 3 meters. This challenge would be shared by all similar low-frequency radiometric missions. On the other hand, such radiometric missions have stringent requirements on the feeds radio frequency (RF) performance so that further technology development is required to enable such missions. In this activity, the design and breadboarding of a wideband, circularly polarised feed antenna is proposed. The challenges of the design and technology selection to be assessed are selection shall be focused on minimum dimensions and mass on the one hand and large bandwidth, low loss, low sidelobes, and high phase centre stability on the other hand. Besides the radiating element, also the required feed chain shall be assessed. Critical elements shall be breadboarded and RF measured.