Filtering Dipole Antenna Design

In this paper, a compact third-order filtering dipole antenna is proposed. A U-shpaed parasitic element is coupled to the original dipole to become a second-order filtering antenna with one radiation null. Then a microstrip stub is added to the balun of the dipole antenna to further increase the order and enhance the selectivity of the filtering antenna without taking up extra space or cost another substrate. A single-polarized printed dipole that cover 2.3-2.7 GHz with good out-of-band suppression is simulated to verify the design and good results are obtained.