Advancing 5G Connectivity: A Comprehensive Review of MIMO Antennas for 5G Applications

Table 2

Performance enhancement techniques of MIMO antenna with advantages and disadvantages.

Reference no	Performance enhancement techniques	Advantages	Disadvantages
[39], 2020	Substrate selection	Substrate’s low permittivity characteristics offer a wide bandwidth, improved gain, and high efficiency.; Having high permittivity increases the return loss value.	Low permittivity substrate is costly and difficult to procure.
[40, 41]	Decoupling/mutual coupling reduction	Optimizes the gain and efficiency while greatly improving the impedance matching.; Reduced mutual coupling reduces the decrease in antenna size.	Mutual connection affects antenna design and makes it more complex.
[42, 43]	Multielement	Significantly increases bandwidth, radiation efficiency and return loss.; Effectively decreases back-lobe levels effectively reduce side.	The feeding network for such systems is challenging to design and adds a certain amount of complexity.
[16, 44]	Corrugation	Gain, bandwidth, efficiency, and return loss improvements can be made.	Reduces input impedance considerably.
[20, 24]	Dielectric lens	Improved front-to-back ratio increases with stable radiation pattern. Increased gain, improved back-to-back ratio, stability in radiation patterns, and radiation in the front-facing direction.	As antennas expand in size, the price of manufacturing them also raises.