Single-Ended Band-Notched Vivaldi Antenna With Common Mode Suppression and Low Cross Polarization

In this letter, a differential-fed band-notched Vivaldi antenna with common-mode (CM) suppression and low cross polarization is proposed. Under CM excitation, the antenna cannot be excited as the CM
E
-field is not supported by the virtual magnetic wall, realizing a high level of CM suppression. Under differential mode excitation, the antenna could radiate effectively with a broadside beam. Moreover, the cross-polarized
E
-field component is reduced due to the symmetric configuration with differential feeding arrangement, which gives rise to lower cross polarization. Meanwhile, the notched band can be obtained by simply turning the microstrip feeding stubs, without extra structure. To achieve a single-ended differential-fed antenna structure, spatial reversal is applied to the feeding arrangement for 180° phase difference, no need of the phase-shift circuit. Finally, the proposed antenna is fabricated and measured. It is demonstrated that the proposed antenna with simple configuration supplies high level of CM suppression, better cross-polarization characteristic below −30dB and a notched band from 3.75 to 4.3 GHz.