Japan 920 MHz WPT License-Free: MIC Opens Outdoor Use

Japan 920 MHz WPT License-Free Reform: MIC Opens Outdoor Use and Adds a New Specified-Low-Power Tier

Japan's Ministry of Internal Affairs and Communications (MIC) has reformed how space-transmission wireless power transfer (WPT) systems in the 920 MHz band may be deployed. The change does two things: it lifts the long standing indoor only restriction to permit outdoor use within a premises, and it establishes a new, output limited category that can operate without an individual radio station licence. For companies building WPT transmitters and the sensors they power, this reshapes both the market opportunity and the route to certification in Japan.

This article covers the equipment level detail manufacturers, importers, and test labs need. It concerns the 920 MHz space transmission WPT reform specifically not the RFID rules in the same band, which are unchanged.

Regulatory context: what changed and why

Space transmission WPT (Japanese: 空間伝送型ワイヤレス電力伝送), sometimes called "beam WPT," transfers power wirelessly over roughly 5–10 metres and is used to power sensors and low consumption devices in factories, warehouses, care facilities, and building management deployments.

Japan first institutionalized these systems in May 2022, allocating three bands 920 MHz, 2.4 GHz, and 5.7 GHz for indoor only operation under a licensed class known as the wireless power transmission premises radio station (無線電力伝送用構内無線局). The 920 MHz band saw the widest uptake because its lower propagation loss reaches sensors spread across an area and around obstructions.

Two limitations held the technology back: operation was confined indoors, and every installation required a station licence a high hurdle for appliance class or consumer-adjacent products. MIC referred the matter to the Information and Communications Council, which delivered its partial report (答申) on 20 October 2025 setting out the technical conditions for outdoor use and for an output limited, licence free tier. MIC then developed the implementing rules through the Radio Act Enforcement Regulations and an associated specified low power notice; the Radio Regulatory Council concurred on 11 March 2026, public comment ran 14 March–13 April 2026, and MIC published the comment results on 23 June 2026 ahead of finalizing the relevant provisions.

Scope of the reform: two core changes

Outdoor use within a premises is now permitted

The indoor only restriction on 920 MHz WPT premises stations is relaxed so systems may operate outdoors within a controlled premises including partially open spaces such as loading bays, and areas where people come and go subject to safety and interference conditions.

A new licence free "specified low power" WPT tier (≤250 mW)

Alongside the existing licensed stations (which operate up to 1 W), the reform introduces a specified low power radio station (特定小電力無線局) category for WPT. By capping transmitter output at a maximum of 250 mW, these systems can operate without an individual station licence. Delivered power is lower, but removing the licensing step is intended to open the technology to broader, faster deployment including consumer adjacent products already being demonstrated by Japanese manufacturers.

Safety and coexistence conditions

• RF exposure protection: operation must satisfy Japan's Radio Frequency Protection Guidelines (電波防護指針), with a required cut off so power transfer halts when a person enters a field that would exceed the controlled environment guideline value.

• Interference coordination: because the 920 MHz band already hosts RFID, active-sensor systems, and LPWA, deployments rely on a coordination scheme (publishing planned deployment information and coordinating with incumbents where concerns arise).

• Emission limits: the reform sets spurious/unwanted emission allowances for WPT specified low power stations.

  
  

What Japan 920 MHz WPT license free rules mean for manufacturers

1. A lower-friction route to market for WPT transmitters. The ≤250 mW licence-free tier removes the individual station licence step, shortening deployment where per site licensing was previously uneconomic.

2. Licence free does not mean certification free. A specified low power WPT station is expected to require certified radio equipment (技術基準適合証明, the Giteki mark) from an MIC designated Registered Certification Body (RCB) before market placement. Budget for equipment certification even where no station licence is needed.

3. Design the transmit stop function in early. RF exposure compliance is enforced through a required cut off. Treat it as a hardware/firmware safety design constraint, not paperwork.

4. Two tiers, two rulebooks. Higher power (up to 1 W) 920 MHz WPT continues under the licensed premises station regime now with outdoor within premises use available while the new ≤250 mW tier follows the licence free specified low power regime. Confirm which tier a product targets before test planning, because the technical conditions differ.

5. Coordination obligations sit with deployers but shape product positioning. Manufacturers selling into Japan should be ready to support customers with the technical data those obligations require.

6. Existing indoor installations are unaffected in their current use, and may be extended outdoors within a premises once compliant with the new conditions.

   
   

Certification impact summary

Item	Before this reform	After this reform
Bands in scope	920 MHz / 2.4 GHz / 5.7 GHz (indoor)	Reform applies to 920 MHz (outdoor within premises + new low-power tier)
Where usable	Indoor only	Indoor and outdoor within a premises (conditions apply)
Licensed tier	WPT premises station, up to 1 W, licence required	Unchanged power; outdoor-within-premises use added
Licence-free tier	None	New specified-low-power WPT station, ≤250 mW, no station licence
Equipment certification	Giteki (technical conformity) via RCB	Still required licence free ≠ certification free
RF exposure control	RF Protection Guidelines	RF Protection Guidelines + required transmit-stop function
Coexistence	Indoor coordination	Interference coordination scheme (deployment disclosure/coordination)
RFID (920 MHz)	Licence/registration required	Unchanged not made licence exempt by this reform

Timeline and required actions

Date	Milestone	Status	Required action for industry
May 2022	920/2.4/5.7 GHz WPT institutionalized (indoor, licensed)	Confirmed	Baseline; existing installations continue
20 Oct 2025	Council partial report (答申) on outdoor-use technical conditions	Confirmed	Begin product/roadmap planning for both tiers
11 Mar 2026	Radio Regulatory Council concurs with draft amendments	Confirmed	Confirm draft technical standards; scope test plans
14 Mar–13 Apr 2026	Public comment on specified-low-power notice	Confirmed	—
23 Jun 2026	Public-comment results published	Confirmed	Finalize certification (Giteki) and transmit stop design
Effective date	Outdoor-within-premises use + ≤250 mW licence-free tier available	confirm exact promulgation/effective date	Align Giteki certification and transmit stop design; brief Japanese customers on coordination obligations