A double-discone antenna,for on ultra-wideband-frequency scan is pretsented. An exquisile assembly of two inverse-feeding discone antennas shows a 30:1 broad bandwidth with VSWR below 2.5 and an omnidirectional radiation pattern. These features make the proposed antenna very suitable for both the UWB system antenna and the wideband scan antenna. (C) 2004 Wiley Periodicals, Inc.