WG4 group will cover a very important aspect of efficient THz radiation coupling. The general task of this WG will be determination of material parameters, design of passive elements (antennas, lenses, and filters) as well as optimization of their coupling with active sub THz and THz devices. One of the very important challenges of radar and vision systems is also development of active, reconfigurable antennas. The WG4 should rely on existing developments of reconfigurable antenna arrays (working at lower frequency) and, generalising, on the state-of-the-art devices provided by WG3. WG4 should propose design, implementation and packaging of systems with reconfigurable antennas in sub-THz range. Design of interconnections and packaging of high frequency integrated sub-systems requires good cooperation between teams of varying expertise (antennas, optics and semiconductor devices) to accommodate, often contradicting, requirements of different technologies. Important task of WG 4 group will be research on efficient integration and packaging of THz-IC with antennas and optics to obtain single-chip high coupling efficiency, small size, low power consumption and low cost transmitters and receivers. Besides design, computing and modelling of on-chip antennas and diffractive optics this Work-Group will make full characterization of fabricated and packaged sub-systems using advanced sub-THz probe stations and anechoic chambers.