An array of antennas provides additional degrees of freedom in the spatial domain compared to a single antenna, which, with the aid of advanced signal processing algorithms, can be exploited for interference suppression/beamforming, direction of arrival estimation, target tracking, and localisation. It has a wide range of applications such as wireless communications, sensor networks, radar, satellite navigation, and biomedical engineering. In particular, with the extensive research activities devoted to the next generation wireless communication systems, antenna array design and signal processing have received unprecedented attention since the two underpinning 5-G technologies, massive MIMO and millimetre wave communications, are all based on antenna array systems.

The aim of this special issue is to present the most recent advances in the area of design and signal processing for various antenna arrays and their applications. We invite both review articles and original contributions from researchers working in this very important area.

Potential topics include, but are not limited to:

• Antenna array design, measurement, and calibration, such as the multiple feed per beam (MFB) focal arrays, multiband/broadband antenna arrays, compact antenna arrays, multipolarization antenna arrays, and on-chip antenna arrays
• Time-modulated antenna array design and signal processing
• Beamforming and direction of arrival (DOA) estimation based on antenna arrays
• Antenna array design and processing for massive MIMO and millimetre wave communications
• General sensor array processing methods and algorithms applicable to antenna arrays