The ITU IMT-2020 Standardization: Lessons from 5G and Future Perspectives for 6G

The evaluation of candidate International Mobile Telecommunications-2020 (IMT-2020) radio interfaces ended in February 2021, with three technologies being approved while another two were granted additional time to demonstrate their suitability. This marks a useful milestone at which the International Mobile Telecommunications (IMT) standardization process can be evaluated, and its implications for 6G explored. We argue that the relationship between IMT standardization and identification is increasingly problematic, with identification requiring the refarming of spectrum already allocated to other services. Furthermore, as standardization is largely done outside of the International Telecommunication Union (ITU), being part of IMT is largely a way to obtain more spectrum. While these developments question the value of the existing approach, we argue that changes are necessary to the IMT standardization processes given the value to be gained from a single global mobile standard

Terahertz integration platforms using substrateless all-silicon microstructures

The absence of a suitable standard device platform for terahertz waves is currently a major roadblock that is inhibiting the widespread adoption and exploitation of terahertz technology. As a consequence, terahertz-range devices and systems are generally an ad hoc combination of several different heterogeneous technologies and fields of study, which serves perfectly well for a once-off experimental demonstration or proof-of-concept, but is not readily adapted to real-world use case scenarios. In contrast, establishing a common platform would allow us to consolidate our design efforts, define a well-defined scope of specialization for “terahertz engineering,” and to finally move beyond the disconnected efforts that have characterized the past decades. This tutorial will present arguments that nominate substrateless all-silicon microstructures as the most promising candidate due to the low loss of high-resistivity float-zone intrinsic silicon, the compactness of high-contrast dielectric waveguides, the designability of lattice structures, such as effective medium and photonic crystal, physical rigidity, ease and low cost of manufacture using deep-reactive ion etching, and the versatility of the many diverse functional devices and systems that may be integrated. We will present an overview of the historical development of the various constituents of this technology, compare and contrast different approaches in detail, and briefly describe relevant aspects of electromagnetic theory, which we hope will be of assistance.Daniel Headland, Masayuki Fujita, Guillermo Carpintero, Tadao Nagatsuma, and Withawat Withayachumnank

Electromagnetic Modeling Methods for Microstrip Patch Antennas up to the Millimeter-Wave and Sub-Terahertz Bands

In the current world of highly integrated communications, reliable and robust systems will be required to develop the 6G networks. The millimeter-wave band (30 GHz–100 GHz) and the sub-terahertz band (100 GHz–300 GHz) have promising possibilities in radar and communication systems, such as broad bandwidth, device miniaturization, and high integration with electronic technology. As 6G communications will be the dominant technology in the coming years, highly-accurate antenna design is becoming essential to building systems that meet the expected performance standards. Despite the wide availability of antenna models working at frequencies below 10 GHz, they need to be in-depth reviewed and reformulated, especially in the sub-terahertz band. Thus, the work developed in this doctoral dissertation provides a framework of analytical methods for electromagnetic antenna modeling, enabling the design of microstrip patch antennae up to 300 GHz. This work covers unprecedentedly diverse models in frequency ranges from radio frequency to the sub-terahertz band. The proposed model formulations consider the geometrical and electrical imperfections of materials used for antenna design. They show high accuracy in the modeled frequency response for measured antennas and transmission lines up to 110 GHz; and for simulated microstrip patch antennas up to 300 GHz, with thickness up to 5 % of the free-space wavelength, copper layers up to 35 μm thick, and with surface roughness up to 1 μm