Integration of Sub-6 GHz and mm-Wave Antenna for Higher-Order 5G-MIMO System

• Published in: IEEE transactions on circuits and systems. II, Express briefs Express briefs, 2022-12, Vol.69 (12), p.4834-4838
• Main Authors: Saurabh, Arun Kumar, Meshram, Manoj Kumar
• Format: Article
• Language: English
• Subjects: 5G mobile communication; 5G new radio; Antenna arrays; Antennas; Correlation; Ground plane; Microstrip antennas; Millimeter waves; millimeter-wave; MIMO communication; multiple-input-multiple-output; mutual coupling; Shaped substrates; Smart phones; Smartphones; Substrates; wideband
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2022.3197598

An extremely low-profile/compact MIMO system is proposed by utilizing the dual antenna for 5G sub-6 GHz and mm-wave application. The antennas are integrated on a centrally located square-shaped slot-loaded octagon-shaped substrate board area of 3706.69 mm2. The identical dual antenna elements with the same orientation are orthogonally placed on an octagon-shaped substrate from the outer side, creating an 8-element MIMO antenna for sub-6 GHz application. From the inner side of the same substrate, a 1\mathbf {\times }4 array-based antenna is orthogonally placed in front of the remaining side of the octagon, forming a 4-element MIMO antenna for mm-wave application. The edge-to-edge separation between element-1 and -9 is almost close to \lambda _{0} /64 ( \lambda _{0} at 4.0 GHz). The stubs are connected to shared ground plane to reduce the coupling between closely placed antenna elements. The MIMO system provides dual −6 dB impedance bandwidth of ( S_{ij}{}_{\,\,} \mathbf {\mathrm {\in }}\,\,{i} = {j} , 1 to 8) 4.0-5.6 GHz and ( S_{ij}{}_{\,\,} \mathbf {\mathrm {\in }}\,\,{i} = {j} , 9 to 12) 24.25-29.5 GHz, can cover the 5G n79//n257/n258 bands. It has a minimum isolation ( S_{ij~}\mathbf {\mathrm {\in }}~{i} \mathbf {\mathrm {\ne }} {j} ) value of 12 dB and 22 dB, respectively. Also, the peak gain and total efficiency values for element-1 and -9 are 5.4 dBi and 8 dBi, and 56.5-77.4% and 70.3-96.2%, respectively. The measured and simulated results are found in close agreement those confirming that the proposed MIMO system may be a suitable candidate for 5G-smartphones. Due to 0.508 mm low-profile, antenna is integrated within the back cover of smartphones, thereby inside device volume will reduce.