This report provides a summary of activities from the work of the CELTIC-NEXT AIMM project Work-Package 3 (WP3) on “Antenna Arrays and Reconfigurable Intelligent Surfaces”. These include all results obtained on topics of work within WP3, namely on “Antenna Array Geometries”, “Reconfigurable Intelligent Surfaces”, and “Power Amplifier Enhancements”. Dissemination activities and future plans are also captured in this deliverable.