Compact Annular-Shaped Four-Port MIMO Antenna for Mid-band 5G/Wi-Fi/Bluetooth/ISM Band/WLAN and IoT Applications

A four-port annular ring patch antenna with a symmetrical slotted partial ground structure for mid-band 5G/Bluetooth/Wi-Fi/ISM band/WLAN and IoT applications at an operating frequency of 2.5 GHz is proposed. The proposed geometry is fabricated over the FR-4 epoxy substrate with dielectric constant 4.4, thickness of the substrate 1.6 mm, and loss tangent of 0.02. Moreover, the complete electrical dimension of presented design is 0.62\(\lambda _{0} \times \) 0.48\(\lambda _{0} \times \) 0.013\(\lambda _{0}\), where \(\lambda _{0}\) is wavelength in the free space corresponding to the resonating frequency (i.e., 2.5 GHz). In the proposed work, for enhancing the isolation a vertical slotted strip is used in the middle of the ground plane. Furthermore, we also enhanced the MIMO parameters performances, such as a low envelope correlation coefficient (ECC) between antenna elements, good diversity gain (DG), low channel capacity loss (CCL), acceptable mean effective gain (MEG), and better total active reflection coefficient (TARC) in the operating band. Moreover, due to four elements the presented work provide the higher data rates, excellent throughput of the signals and improve communication reliability as well as signal strength. The values of different parameters obtained for the proposed structure are as follows; antenna realized gain of 4.65 dBi, total efficiency of 96%, ECC < 0.025, DG is 9.98 dB, CCL < 0.012 bits/s/Hz, and MEG lies in between \(-\) 3 dB and \(-\) 12 dB. Throughout the band, the maximum isolation achieved among all ports is < \(-\) 26.4 dB. The overall frequency range for which reflection coefficient < \(-\) 10 dB is 2.36 to 2.99 GHz.