Multi-Resonant Cavity-Backed Slot Antennas with Enhanced Bandwidth and High Isolation

A novel cavity-backed slot antenna with dual-polarization, enhanced bandwidth, and high isolation characteristics is proposed in this letter. The antenna features a central resonant cavity with multiple radiation slots and two orthogonal feeding cavities to realize dual polarization. By combining the fundamental cavity modes with the slot modes, the operational bandwidth is significantly extended. The incorporation of multiple radiation slots not only improves the radiation gain but also contributes to better impedance matching. Furthermore, the designed feeding configurations minimize coupling between the two ports, thereby ensuring excellent isolation. The measured results show an 11% relative bandwidth from 3.275 GHz to 3.675 GHz under the requirement of S ₁₁ < −10 dB, while maintaining excellent isolation exceeding 45 dB. With these favorable characteristics, the antenna is well-suited for integration into high-power communication platforms.