A Novel Directive, Dispersion-Free UWB Radiator with Superb EM-Characteristics for Multiband/Multifunction Radar Applications

The number of topside shipboard antennas doubled every decade; in 1990s they were close to 200 and have no sight of stop growing (Tavik, 2005). The over-crowded present of such many topside antennas in a limited-space of littoral warfare ship has created/caused many critical, unavoidable problem like antenna blockage, electromagnetic interference, increase RCS, worsen the effective stealthy signature of combatant ships, which is stealthy-intended designed, and most of all is the maintenance costs of multiple systems, huge numbers of repair-personnel and operators (Tibbitts & Baron, 1999). As modern warfare ships continue to require higher levels of functionality, performance and interoperability, these problems became so bad and unresolvable and gradually as severe as unacceptable. Much efforts around the globe are concurrently conducting research works on shaping their warfare sensors/systems to form network centric warfare (NCW) ready for network centric operations (NCO). As part of the NCW, combatant ships (LCS, DDX, CGX etc.) are moving towards the governing of their integrated and centralised sensor systems, in which both ITD (integrated-topside-design of radars, and electronic warfare), and TSDC (Top Side Design Communications of civil/military communications) are being seriously investigated. The frequency occupation on board of a warship is extremely wide, from several Hz to hundreds of GHz. To reduce the topside antenna problem, with restriction to the RF sensors only, it may better to divide the occupied frequency spectrum into a number of spectra based on their related tasks. The number of spectra can be roughly divided in four main spectra: 1) VHF-UHF-L band, 2) S-band, 3) X-Ku band, and 4) K-Ka-Q band.