Modern telecommunication systems such as radio links, radars, and mobile devices require antennas able to operate in different complex environments. In particular, new mobile devices such as smart phones, tablets, IoTs, and wireless sensor networks offer different complex services that require high gain beam forming and steering capabilities in spite of the limited dimensions of the devices. In particular, in addition to usual voice and other services of standard previous systems, 5G generation devices offer ultrabroadband Internet connection, IP telephony, mobile web access, and other interesting multimedia applications. In such a framework the design of a suitable radiating system could play a key role in the design of new generations of telecommunication systems. Antennas for these devices must be compact, light, cheap, and able to keep their performance at high levels in any kind of environment. In such a framework the use of compact and multifunction antennas characterized by adaptive properties is mandatory to dramatically improve the performance of a telecommunication system. Moreover, these kinds of antennas can be used in several fields of practical military as well as civil applications. In particular, radars with these characteristics can be very useful for airport surveillance and security, collision avoidance, ground radar, and monitoring and tracking of Unmanned Aerial Vehicles (UAVs). Concerning military applications, the use of smart antennas can be very useful for missile detection and tracking, antiaircraft defense artillery and identification friend or foe (IFF) systems.

The objective of this special issue is to provide an overview of the current research on smart antennas, the potential to adapt their characteristics to different scenarios, and to highlight the latest developments, innovations, challenges, and opportunities of their application.

Potential topics include but are not limited to the following:

• Reconfigurable arrays
• Ultrawideband antennas
• MIMO antennas
• LTE antennas
• Fractal antennas
• Airport surveillance antennas and radar systems
• Collisions avoidance systems
• Missile detection and tracking
• Identification friend or foe (IFF) systems