Radio Regulations

Source: the Radio Regulations published by the International Telecommunication Union (ITU).

WRC Agenda Item › WRC-27 › AI 1.8
AI

1.8

WRC-27 · Agenda item 1.8

to consider possible additional spectrum allocations to the radiolocation service on a primary basis in the frequency range 231.5-275 GHz and possible new identifications for radiolocation service applications in frequency bands within the frequency range 275-700 GHz for millimetric and sub-millimetric wave imaging systems, in accordance with Resolution 663 (Rev.WRC-23)

Current WP 5B Res. 663 (Rev.WRC-23) › 231.5–275 GHz 275–450 GHz 275–700 GHz
At a glance Summary & background Regulatory Studies

At a glance Beta

Frequency band
231.5–275 GHz 275–450 GHz 275–700 GHz
Governing resolution
Res. 663 (Rev.WRC-23)
Responsible group WP 5B
Agenda-item type Technical

The band and its sensitive neighbours

231.5–275 GHz Radiolocation Earth exploration-satellite 275–450 220 231.5 275 460 GHz
Radiolocation
Earth exploration-satellite

Blocks group a service with its direction and mode variants; the table names each allocation as the Radio Regulations name it.

Current framework

Services in this band

Radiolocation Primary proposed across 231.5–275 GHz; narrower existing allocations lie within the range

What's being studied — points to watch

Passive science protection

EESS (passive) and radio astronomy above 275 GHz observe faint natural signals and cannot tolerate active-radar interference.

Identifications vs allocations

275–700 GHz works by identification, not allocation: No. 5.565 identifies the passive-service bands, and No. 5.564A identifies 275–450 GHz for fixed/land-mobile use with passive-protection conditions. Radar identifications must fit around both.

Where radar fits

Finding sub-bands where security and imaging radar can operate without overlapping the sensitive passive windows — noting that within 231.5–275 GHz, all emissions are already prohibited at 250–252 GHz (No. 5.340).

Active/passive coexistence

This region was historically reserved for science; adding active use sets a precedent that needs careful limits.

Preparation timeline

  1. Dec 2023 WRC-23 agenda adopted
  2. Dec 2023 CPM 27-1 studies allocated
  3. ITU-R studies 2026
  4. ITU-R studies 2027
  5. 5–15 Apr 2027 CPM 27-2 final report
  6. RTO Prep meetings 2027
  7. 11–15 Oct 2027 RA-27
  8. 18 Oct–12 Nov 2027 WRC-27

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Source: ITU Radio Regulations, editions of 2008, 2012, 2016, 2020 and 2024. The English, French and Spanish texts are each taken from the official edition in that language, not translated from one another. Sources and citation.