the "physical layer" (PL), which describes the implementation of bits transmission through the communication channel. Many exciting new ideas have been proposed at the PL level for 6G. Some of them are based on the use of very high frequencies, f.i. sub terahertz frequencies and visible light, to obtain ultra-broadband communication systems. As in past generations of cellular systems, the improvements are concentrated in the time channel. At the same time, extensive research is underway on innovative radiating systems to obtain a high degree of control of the electromagnetic environment. As mentioned above, the idea is to modify the electromagnetic environment by controlling the space channel. This is a disruptive change of perspective in communication theory, which promises extremely high performance in terms of data rate and number of users served by the network without cost in terms of bandwidth. Radiating systems can be "packaged" in a limited area, or they can be spread over larger areas and work cooperatively, as happens in so-called "user centric cells." All these solutions are focused on the efficient use of the space channel by increasing the amount of information that can be reliably transmitted per "unit of space." Application Network process to applications layer Presentation Data representation and encription layer Session Intern-host communication layer Transport Segments End-to-end connections and reliability layer Network Packets Path determinations and IP layer Data link Frames layer Physical access MAC and LLC Physical Media, signal andbinary transmission layer Deep physical Fields First principles layer Fig. 2.1 The OSI model extended including the Deep Physical Layer [19] 2 Information Flows at the DPL Level With reference to the efficient use of the space channel, the different ideas regarding 6G antennas can be grouped in two main research directions: Active Large Apertures (ALAs) and Passive Large Apertures (PLAs). ALAs include a number of technologies such as Massive Very Wide Aperture MIM