The recent progress in 5G wireless technology is becoming more intense due to the completion of the 5G (Frequency Range 1, FR1) infrastructure in many regions worldwide. To realize futuristic wireless devices (including 5G/B5G and Wi-Fi 6E), wireless RF antenna engineers have played an important role to yield good aesthetic design, improving the total frequency link budget, and permitting multiple users to use the single interface, thereby increasing the channel capacity/throughput. Amid the design of an RF system for futuristic wireless devices, the RF antenna is one of the most vital components.

However, most conventional antenna designs have encountered difficulties in satisfying the stringent requirements layout in the present 5G communications, such as the need to operate across very wide operational bandwidths (5G New Radio FR1 and FR2), high gain, directional radiation patterns with beam steering, smaller size for mobile devices (especially the smartphone), and low-cost. Furthermore, due to the recent introduction of 5G/B5G, Wi-Fi 6E, and low-earth orbit (LEO) satellite wireless technology, traditional antenna designs (such as loop, PIFA, monopole, dipole) may become obsolete, hence there is an imminent need to develop novel antenna design techniques and intelligent antenna systems. The massively increasing volume of data transfer rate via futuristic wireless technologies has resulted in a dilemma; in which the capacity/bandwidth of the RF band is finite. Therefore, the multiple-antenna technology is applied as it can easily outperform the single-antenna technology. The multiple-antenna technology includes array antennas and multiple-input–multiple-output (MIMO) antennas. The array antennas can yield much higher antenna gain with wide bandwidth, while the MIMO antennas can provide better communication links within the same channel without the need for additional bandwidth or transmission power. Therefore, the multiple-antenna technology is one of the most powerful technologies for futuristic wireless devices, as it can tremendously increase the data transfer rate and channel capacity of wireless links by sending independent signals from many different transmit antennas. To date, the MIMO antenna technology is a prerequisite requirement for 5G systems and their related futuristic wireless devices. Thus, the demand for different types of novel and high-performance MIMO antennas designs is increasing exponentially.

This Special Issue aims to review the current situation and identify further research areas in this exciting field of 5G MIMO antenna technologies and novel antennas designed for futuristic wireless devices. We invite researchers and practicing engineers to contribute original research and review articles.

Potential topics include but are not limited to the following:

• MIMO Antennas for 5G Wireless Communications
• MIMO Antenna Array Design
• Millimeter-wave Antennas for 5G Wireless Communications
• Smartphone Antennas
• MIMO Antennas for Portable Devices
• Beamforming and Smart Antennas for 5G Wireless Communications
• Reconfigurable MIMO antennas
• Flexible MIMO Antennas
• Transparent MIMO Antennas
• Phased-Array Antennas
• MIMO Antennas for Wearable and Textile Applications
• Metamaterial-based MIMO Antenna
• Dielectric Resonator (DRA) based MIMO Antennas
• Substrate-Integrated Waveguide (SIW) based Antennas
• Low-profile MIMO Antenna for Internet of Things (IOT)