An updated version of the Dyson Conical Quad-Spiral Array (DYQSA) feed system for VGOS applications

This paper presents the design of an updated version of the dual polarized ultra wideband feed system for covering the new VGOS (VLBI Global Observation System). This feed system is based on an array version of four elements of the self-complementary conical log spiral antennas. The feed system achieves the VGOS's requirements with operating with high efficiency (> 50%) in a wide bandwidth from 2 GHz to 14 GHz. It provides two attractive characteristics: dual circular polarization compared to dual linear ones in the state of the art solutions and also a real and constant input impedance in the whole operation band.