The Design of UWB Bandpass Filter-Combined Ultra-Wide Band Antenna

We have proposed a compact filter-combined ultra-wide band antenna for the use of DS-UWB low band or MB-OFDM lower three bands (3.1-5.2 GHz). The designed antenna has a microstrip-fed trapezoidal radiating patch, UWB band pass filter using the dumbbell-shaped DGS (defected ground structure) and IDC (interdigital capacitor), two steps for impedance matching, and microstrip feeding. Three kinds of prototypes (trapezoidal UWB antenna, UWB band pass filter, and the compact filter-combined ultra wideband antenna) are fabricated and measured. The designed antenna has the figure-of-eight radiation pattern, wide bandwidth, and negligible dispersion over the operating frequency band. Details of the proposed antenna design and the simulated and measured results are presented and discussed.