Tapered direct fed bifilar helix antenna

摘要

A tapered direct fed bifilar helix antenna comprises bifilar antenna elements which helically spiral around an antenna axis to define an outer cylindrical shape of the direct fed bifilar helix antenna. The width of the bifilar antenna elements at the feed end of the antenna is sized to provide the antenna with an approximately fifty ohm characteristic impedance. The individual filar elements taper at a predetermined axial position from a maximum width at the feed end to a minimum width at the end furthest from the feed end. A fifty ohm coaxial cable directly feeds the tapered bifilar antenna elements.