The Radio Regulations provide an international framework for the management of radio frequencies up to 3 THz, with agreed frequency allocations stopping at 275 GHz.
Frequency allocations between 90 GHz and 275 GHz were decided at WRC-2000 (World Radiocommunication Conference), within the frame of agenda items 1.16 and 1.17. They provided visibility to stakeholders on available frequencies for a large set of radiocommunication services. ITU-R studies performed at that time indicated that sharing between the EESS (passive) and the fixed service is generally possible in frequency bands with high atmospheric absorption but may require constraints to be applied on the fixed service to protect passive space sensors. With respect to the protection of the terrestrial radioastronomy service, it was indicated that national administrations may have to establish coordinationzones around millimetre-wave astronomical observatories. Coordination radii in the order of 100 km may be necessary.
Frequencies that may be used by active radio systems are bordered by “passive” bands i.e. bands covered by footnote RR No. 5.340 which prohibits all emissions in dedicated frequency bands. Of relevance to operation within the range 90−275 GHz, the following bands are affected by this footnote: 86-92GHz, 100-102 GHz, 109.5-111.8 GHz, 114.25-116 GHz, 148.5-151.5 GHz, 164-167 GHz, 182-185GHz, 190-191.8 GHz, 200-209 GHz, 226-231.5 GHz and 250-252 GHz.
In practice, the frequency bands allocated to the fixed and mobile services in the range 90-275 GHz provide a framework for the development of terrestrial wireless communications: 92-94GHz, 94.1-100 GHz, 102-109.5GHz, 111.8-114.25 GHz, 122.25-123 GHz, 130-134 GHz, 141-148.5 GHz, 151.5-164GHz, 167-174.8GHz, 191.8-200GHz, 209-226GHz, 231.5-235GHz, 238-241GHz, 252-275GHz.Effective regulatory solutions at European level should be based on RR frequency allocations. Their development and national implementation are driven by market demand. They should define adequate conditions to ensure coexistence with other radiocommunication services and protection of passive services operating in adjacent bands.
Investigations within CEPT (European Telecommunication Office) based on the requirements expressed by ETSI have led to the publication in 2018 of European harmonisation measures for fixed service systems in the frequency ranges 92-114.25 GHz (“W-band”) and 130-174.8 GHz (“D-band”).
Besides, it is worth noting the frequency bands 122-123 GHz and 244-246GHz are available in Europe for SRD (Short Range Devices) in accordance with the technical conditions recommended in annex 1 of ERC/REC 70-03 (see also ETSI EN 305550).