A Differential Slot-type Dual-polarization Ultra-wideband Antenna

A differentially fed dual-polarization slotted antenna with an ultra-wide bandwidth and low cross polarization is presented in this paper. The antenna is composed of a radiation patch and a ground plane, both of which are printed on the top of the dielectric substrate. The ground is extended toward the radiation patch to form a slotted coplanar structure. In order to expand the bandwidth, a cross-shape symmetrical slotted structure is loaded into the radiation patch. Differential feed is adopted to realize 0∘/90∘ linear polarizations and suppress the cross polarization. Simulation and measurement results show that the proposed antenna with dimensions of 0.53λ0× 0.53λ0 × 0.0135λ0 (λ0is the wavelength at 4 GHz) has a differential mode impedance bandwidth of 82.25% (2.27-5.56 GHz), a differential feed port isolation of higher than 28 dB, and a cross polarization level of less than −30 dB, which achieves the characteristics of ultra-wideband, high isolation, and low cross polarization level.