Shared-Radiator Design of Dual-Band Coplanar Base Station Antenna Array Using Cavity-Backed Slots

In this communication, we propose a shared-radiator design concept for dual-band base station antenna arrays. To realize the concept, novel differentially fed dual-polarized slot antenna is devised to be the high-band (HB, 3.4-3.6 GHz) radiator, while the large slot ground can be reused as the radiating arm of the low-band (LB, 0.69-0.96 GHz) crossed dipole. Reflective cavities are introduced to back the HB antennas, building clear and independent radiating environments for the two operating bands. A dual-band base station antenna array with one LB dipole antenna and four HB slot antennas is designed, by adopting the proposed integration concept. Good impedance matching (voltage standing wave ratio 29.5 dB in the LB and > 26.6 dB in the HB) are obtained. Owing to effective decoupling between the two bands, stable radiation patterns are also achieved.