Radio Astronomy Ultra Wideband Receiver Covering The 2-14 Ghz Frequency Band For Vgos Applications

The requirements for the VGOS (VLBI Global Observation System) [1] are: feed system covering the 2 to 14 GHz bandwidth and also working with high efficiency (> 50%). Universidad Carlos III de Madrid has developed a new topology to cover them. The new receiver topology is based on a log-spiral antenna printed on a conical surface. Two interesting characteristics are presented: the first one is the dual circular polarization compared with the dual linear polarization recorded in the state of the art [2]. The other comes from the fact that the new topology uses the self-complementary antenna concept, so constant and almost real part of input impedance is obtained, simplifying the design of Low Noise Amplifier (LNA.) An array of four elements is presented for getting all the mentioned requirements. A single ended LNA covering the whole band is also presented together with the proper balun for feeding the antenna.