UWB ANTENNA SIZE REDUCTION METHODS USING FRACTAL, MATRIX, AND SERRATED STRUCTURES

Four ultrawideband monopole antennas exploiting periodicity to reduce their size are presented. Experimental results are also discussed for these antennas. The first antenna uses a fractal topology based on a hexagonal pattern. It achieves a bandwidth of 8.85 GHz from 3.65 to 12.5 GHz with a 14 X 16.52 mm(2) footprint. The second antenna uses an electric-magnetic-electric matrix and provides a 7 GHz bandwidth from 3.5 to 10.5 GHz with a 14 3 15.9 mm(2) footprint. Two antennas based on a serrated structure which reduces the surface up to 15% are also presented with dimensions of 15 3 16.3 mm(2) : the first one covers a bandwidth of 3.5 to 11.73 GHz, whereas the second adds a notch between 5.15 to 5.825 GHz to reject the wireless LAN band. All these antennas can be incorporated into very small communication modules while maintaining excellent performances with a return loss below -10 dB and with a good multidirectional radiation pattern. (C) 2014 Wiley Periodicals, Inc.