# Dual-Band MIMO Antenna for n79 and sub-7 GHz Smartphone Applications
###### Abstract  
The optimal design of Multiple-Input Multiple-Output (MIMO) antennas is significant for next-generation smartphone solutions with the appearance of further communication. This paper describes the design, simulation, and measurements of a ten-element MIMO antenna for n79 at 4.4-5.0 GHz, n102 at 5.925-6.425 GHz, and n104 at 6.425-7.125 GHz ranges that will be implemented in today's smartphones. The proposed antenna system has a maximum dimension of 158 mm \(\times\) 60 mm and will use the low-cost FR-4 as the dielectric material. The design procedure is carried out with a lot of care to ensure that it does not compromise the spatial characteristics and at the same time minimizes the mutual coupling between the nearby antenna dimensions. High isolation and low ECC values are simulated using capturing techniques on the antenna geometry and its element position for proper MIMO performance improvement. The constructed antenna system portrays good performances in the intended bands as evidenced by the reflection coefficient values, radiation patterns, and individual gains. The performance of the above proposed ten-element MIMO antenna system in terms of bandwidth efficiency, diversity gain, and channel capacity loss is discussed. It also satisfies the demands of current standards of wireless communications and provides future possibilities for higher data transmission rates and message reliability in next-generation smartphone applications. Here, the application of the FR-4 substrate is remarkable as it provides comparatively better performance with significantly easier manufacturing and less cost, and thus, the design has good possibilities to be commercially viable. This work can be understood to form part of ongoing research in enhancing the advancement of the smartphone's antenna technology, which offers a scalable approach to the prospective spectrum altitude and the emergent surge in the data rates of mobile communication. MIMO; n79/n102/n104; future generation; smartphone; ECC 202411 10224 1024  
below 6 GHz, sub-6 GHz 5G NR antenna designs at that time were concentrated at the bands of about 3.4-3.6 GHz, mainly including array antennae with operations at dual bands [3; 4; 5; 6; 7]. New developments have brought into the market MIMO antenna designs that can accommodate a broad bandwidth across all the 5G NR frequency bands bands n77/n78/n79 for use in 5G smartphone devices [8; 9; 10]. However, in designing these antennas, there is a tendency to rely on tedious and conventional full-wave electromagnetic simulations (EM). The primary development trend for achieving the necessary spectral efficiency, bandwidth, and channel capacity is the deployment of fifth-generation (5G) networks. Considered the primary band of global interest for 5G communication, the C-band (3300-4200 and 4400-5000 MHz) is emerging as a pivotal frequency range for advancing 5G technology. It offers a balanced combination of coverage and capacity, making it cost-effective for widespread deployment. Since massive MIMO systems with many antennas may achieve enormous data speeds, one of the main areas of focus for 5G system developments [11] is when moving to the higher generations, higher frequency may cause short range and signal path losses, so to dynamically control the signal paths, researchers have used the reconfigurable intelligent surface (RIS) [12; 13] with the existing infrastructure. Reduced isolation and decreased spectral efficiency are mostly caused by the designers' inability to pack several antennas into the tiny area of cell phones. Because of its superior spectral efficiency, a MIMO antenna with wider bandwidth or multiband operation and more separation between antenna parts is widely sought. Nevertheless, it is a difficult challenge to obtain improved spectral efficiency for 5G devices; it is proposed that a multiband antenna with tuning in all the frequencies sub-bands is best-suited.