Differential UWB-dipole antenna with common-mode suppression and sharp-selectivity notched band

A differentially-fed dipole antenna with common-mode suppression and sharp-selectivity notched band for UWB application is proposed in this paper. The proposed antenna consists of a pair of differential ports, a printed dipole, and a stepped slot embedded in the ground which acts as a wideband bandpass filter and transmits the differential signals from the differential ports to the dipole antenna. Under the differential-mode operation, the stepped slot can be effectively excited by the feeding microstrip and differential signals can be transmitted to the dipole. However, under common-mode operation, the stepped slot would not be excited so that the common-mode suppression can be achieved. In order to achieve sharp-selectivity notch-band characteristic, quarter-wavelength slits are etched on the ground and half-wavelength stub is introduced beside the microstrip, respectively. As a result, a second-order notched band with sharp selectivity is obtained. The simulated results show that the proposed antenna obtains good common-mode suppression characteristic and a sharp-selectivity notched band from 5.1 to 6.0 GHz.