High-Isolation Wide-Band Four-Element MIMO Antenna Covering Ka-Band for 5G Wireless Applications
B. G. Parveez Shariff, Akshay Anil Naik, Tanweer Ali, Pallavi R. Mane, Rajiv Mohan David, Sameena Pathan, Jaume Anguera
Abstract
The wireless communication system is steered towards the millimeter wave spectrum to achieve low latency and high-speed data rate. The MIMO antennas aid in attaining a higher data rate. The prominent spectrum at millimeter wave is Ka-band, suitable for short-range communication. The |S-parameter| response and radiation pattern of the existing MIMO antenna at this band are relatively unstable. Hence it encouraged to design and develop a four-element MIMO antenna operating at Ka-band. The antenna is a circular ring shape with two concentric rings with a plus-shape stub overlayed on circular rings. The structure is developed in four-stage with the comprehension of characteristic mode theory (CMA). The proposed structure generated Mode 2 as an efficient mode, with minor Modes 3 and 5 contributing for resonance out of five modes. The overall antenna profile is 3.27λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 3.74λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength at a resonance frequency of 28 GHz). The novel decoupling structure has improved the isolation to 30 dB and increased the bandwidth. The antenna has an operating bandwidth of 24.1-30.9 GHz, with a maximum gain of 6.5 dBi. The |S-parameter| from all the ports has an exact and stable response. The proposed antenna has resulted in bidirectional radiation tilted at an angle of 334° and 210° in the XZ plane. In the YZ plane, it has a triple beam. The radiation pattern is also stable throughout the bandwidth. The proposed MIMO antenna has a symmetrical design, demonstrating the possibility of expansion to n-element MIMO through a six-element MIMO antenna design. The article also presents the channel capacity, path loss, and link margin calculation for designed antenna line-of-sight (LOS) communication. The antenna has been evaluated with diversity parameters such as ECC, DC, CCL, TARC, and MEG.