A 3.5/28 GHz Shared-Aperture Dipole Array with Enhanced Cross-Polarization Suppression

This paper presents a large-frequency-ratio shared-aperture antenna with enhanced suppression of cross-polarization. Based on the previously reported topology, the antenna integrates a 3.5 GHz dipole antenna with a 28 GHz 4-element array. The array employs a double-layer dipole element fed by a stripline to counteract the cross-polarization components. Combined with the separate feeding network of the substrate integrated coaxial line, the array can generate a steerable millimeter-wave beam. The experimental results indicate that the antenna has good performances in both frequency bands, including a cross-polarization lower than -24.5 dB.