A Broadband Dual-Polarized Filtering Dipole Antenna with High Selectivity

A dual-polarized filtering dipole antenna with enhanced bandwidth and high selectivity is presented in this paper. The proposed antenna adopts the cross-dipole structure, containing two radiation units orthogonal to each other to achieve ± 45° linear polarizations. For each dipole unit, the parasitic elements placed perpendicular and parallel to it introduce radiation nulls at lower and higher frequencies, respectively. Through a pair of slits etched on each parasitic element, the roll-off rate at the upper passband edge is further optimized. In addition, the two radiation nulls can be controlled independently by adjusting the inner and outer lengths of the Uslot on the coupling path. To demonstrate the feasibility of this design, the compact dual-polarized filtering antenna is fabricated. Measured results show that the proposed antenna characterizes wide impedance bandwidth, high port isolation, flat in-band gain, sharp band-edge roll-off, and low cross-polarization level.