Antenna systems and propagation are at the core of the development of new wireless technologies, especially for 5G, 6G and beyond wireless networks and applications. Fundamentally, the propagation channel need to be studied in order to design and optimize wireless system performance. Of special relevance is the polarimetric spatio-temporal behavior of the transfer functions between transmit and receive multi-port antennas at different frequency band from MHz to THz. The overall wireless system performance requirements dictates the desired antenna system characteristics, e.g., bandwidth, EIRP, beams scanning, etc. And therefore, also the choice of antenna system technologies for a specific application is influenced by the propagation channel, e.g., frequency band and spatial distribution of users. Hence, the need for the proper modelling of the interactions between the antennas and the propagation channel. In 5G systems and beyond, multiple antenna systems known as massive MIMO play a fundamental role to serve many users with high data bitrates simultaneously over a wide spectrum known as spatial division multiplexing. Antenna systems are integrated into wireless devices of all types (e.g., base stations, smart phones, laptops, vehicles of all type, etc.) and need to be characterized in the research and development stage, also in type approval and conformance testing as well as in the production line. As we are going towards 6G applications, not only small or massive antenna systems deployed in various devices need to be developed, but new ways of enhancing the propagation channel need to be devised. For example, metamaterials and other structures that can be used to facilitate the propagation of electromagnetic waves in desired directions is of great relevance. Therefore, the impact of different solutions need to understood as well as the development of performance characterization methods, especially for the indoor environment. In this talk I will present results and ongoing research related to phased arrays based on the Gap Waveguide (GW) and Magneto-Electric Dipole (MED) technology, antenna-channel interactions in terms of the spherical vector wave (SVW) expansion of the electromagnetic field, over-the-air (OTA) characterization of wireless devices for cellular and automotive applications, e.g., the Random Line-Of-Sight (Random LOS) and the Hybrid Anechoic & Reverberation Chamber (HARC) as well as the concept of Building Wireless Performance (BWP). Co-sponsored by: Morteza Shahpari Speaker(s): Dr Glazunov, Virtual: https://events.vtools.ieee.org/m/273675