ARIB STD-T91

ARIB STD-T91 defines the technical requirements for Ultra-Wideband (UWB) radio systems operating in the 3.4–4.8 GHz and 7.25–10.25 GHz bands in Japan. The standard is intended to enable short-range, low-power wireless communications for applications such as sensing, indoor positioning, and high-speed data transfer.

Scope and Application

The standard applies to UWB systems used in:

• Short-range wireless data links

• Radar-based sensing and motion detection

• Indoor positioning systems

• High-resolution imaging and object tracking

UWB devices are subject to low-power transmission limits and must comply with specific emission masks to minimize interference with existing radio services.

Frequency Bands and Restrictions

• Lower Band: 3.4 – 4.8 GHz
  → General indoor UWB applications

• Upper Band: 7.25 – 10.25 GHz
  → Imaging and radar-type applications

Additional Restrictions:

• Operation is typically limited to indoor use

• Outdoor or vehicular applications require special authorization

Power Limits

• Typical EIRP density: –41.3 dBm/MHz

• Peak EIRP: strictly limited (e.g. –14 dBm per 50 MHz)

• Emission masks must be met to reduce interference

Certification and Labeling

All UWB devices must be tested by a Registered Certification Body (RCB) and labeled with the Giteki mark. Devices must include documentation specifying operational limits and use conditions (e.g. indoor-only).

For support with testing and approval, see our → MIC Certification Services.

Note
A comprehensive overview of device categories, certification process, and Giteki marking can be found in the guide → MIC Requirements – Overview.