Filtered antenna for UWB systems: Band-selective and compact feed by filters/channel-combiners with/without metamaterials

The Ultra-Wide Band(UWB) telecommunication needs to avoid the collision with other service bands and off-limit frequencies. UWB Antennas have been introduced to notches generated by U-slits on the main radiators. To overcome the shortcomings of the narrow bands and not to lose the benefit of a small radiator by filling the limited space with multiple slits, we suggest the efficient method to provide the function of band selectivity for the UWB antenna system instead of forming defects on the main radiators, and complicating the impedance matching adjustment. The feed of the UWB antenna is equipped with compact filters and channel combiners that adopt metamaterials or improved transversal loops, which turns out capability of suppressing the growth in the overall size of the antenna system. We present several design examples of our filtered antenna.