A Dual-Broadband Dual-Polarized Fylfot-Shaped Antenna for Mobile Base Stations Using MIMO Over-Lapped Antenna Subarrays

This paper proposes a novel design of a dual-broadband dual-polarized antenna for mobile communication base stations. The proposed antenna is Fylfot-shaped and covers 0.7–0.96 and 1.7–2.7 GHz simultaneously (with S11 ≤ −10 dB), which are the two common frequency bands for mobile communication systems. Three resonant frequencies are produced in the proposed design where two of them are independently controlled to achieve the dual-broadband performance. A prototype of the proposed antenna has been developed and tested. The results demonstrate that the antenna has high isolation between its ports, high polarization purity, and stable radiation patterns across both the frequency bands. A new linear array is proposed and implemented. Unlike reported dual-band base station antenna arrays, the proposed array uses a novel technique of two MIMO overlapped subarrays with shared radiating antenna elements. The overlapped subarrays have excellent frequency diversity performance with low envelope correlation coefficients. The array has been found to have the same performance as a standard conventional base station antenna but with 25% less number of antenna elements, which leads to a smaller size and lower cost. The simple antenna structure and the novel smart MIMO overlapped antenna subarrays technique give the design the privilege to be an ideal candidate for a low-cost directive base station antenna.