Design and Analysis of 8×1 Wideband Mmwave MIMO Antenna Array for High-Performance 5G UAV Communications

Millimeter-wave (mmWave) fifth-generation (5G) networks play a crucial role in facilitating communication and connectivity for unmanned aerial vehicles (UAVs) within the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{5G}$</tex> landscape. These networks leverage advanced 5G technology to ensure rapid data transfer speeds, minimal latency, and dependable wireless communication, offering vital support for diverse services and applications in the realm of UAV operations. This research introduces a pioneering approach focusing on the development and evaluation of a novel, compact, and lightweight mmWave antenna specifically optimized to enhance communication capabilities in 5G UAV communications. The proposed antenna is designed on an ultrathin 0.254 mm RO5880 substrate with a relative permittivity of 2.3. It features ring structures stacked vertically and a partial ground plane with bent corners and square slots. The single-element antenna, measuring <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$12 \times 15 ~\text{mm}^{2}$</tex>, operates across two frequency bands. The first band spans from 23 to 33 GHz with a 10 GHz impedance bandwidth, while the second band covers 37.75 to 41 GHz with a 3.25 GHz impedance bandwidth, offering gains of 5.69 dBi and 5.01 dBi at 28 GHz and 38 GHz, respectively. The total and radiated efficiency exceeds <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&gt;90 \%$</tex>, making it suitable for practical mmWave devices. Moreover, the fabricated prototype aligns well with the simulated results, validating the antenna design. The proposed single-element antenna is further expanded into an <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$8 \times 1$</tex> Multiple Input Multiple Output (MIMO) linear array (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$96 \times 12 \times 0.254 ~\text{mm}^{3}$</tex>). Noteworthy isolation levels exceeding -20 dB at both bands signify high isolation levels among radiating elements, providing gains of 13.4 dBi at 28 GHz and 12.2 dBi at 38 GHz. The fabricated prototype of the eight-element MIMO system aligns well with the simulations, confirming the effectiveness of the MIMO antenna design configuration. Furthermore, the proposed antenna undergoes testing on a CAD model of an UAV, yielding promising results. These characteristics position the proposed antenna as a compelling choice for integration into mmWave 5G networks, especially in applications related to 5G UAV Communications.