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

Japan: MIC Opens 920 MHz Wireless Power Transfer (WPT) to Outdoor and License Free Use

Japan's Ministry of Internal Affairs and Communications (MIC) has moved to expand how space-transmission wireless power transfer (WPT) systems in the 920 MHz band may be deployed. The reform 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 be operated without an individual radio-station licence. For manufacturers building WPT transmitters and the sensor devices they power, this changes both the market opportunity and the certification pathway into Japan.

This article covers the finalized 920 MHz WPT amendment specifically. It is distinct from GMA Labs' earlier high level coverage of Japan's broader 900 MHz-band reform and the 920/800 MHz consultation, and goes to the equipment-level detail that manufacturers, importers, and test labs need.

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 frequency bands 920 MHz, 2.4 GHz, and 5.7 GHz for indoor-only operation under a licensed station class known as the wireless power transmission premises radio station (無線電力伝送用構内無線局). Of the three bands, 920 MHz has seen the widest uptake because its lower propagation loss reaches sensors spread across a wide area and around obstructions; by the end of March 2025 there were over 470 licensed 920 MHz WPT premises stations in operation.

Two limitations held the technology back from wider deployment: operation was confined indoors, and every installation required a station licence a high hurdle for products such as appliances or consumer adjacent equipment. To address this, 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 proceeded to develop the implementing regulations, promulgated in 2026.

Scope of the amendment: the two core changes for Japan 920 MHz WPT

1. Outdoor use within premises is now permitted

The indoor only restriction on 920 MHz WPT premises stations is relaxed so that systems may be used outdoors within a controlled premises including partially open spaces (for example, loading bays where trucks enter and exit) and areas where people come and go, subject to safety and interference conditions.

2. A new licence free "specified low-power" WPT category (≤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 be operated without an individual station licence. The delivered power is lower, but the removal of the licensing step is intended to open the technology to easier, broader deployment including prototype consumer facing 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). A mandatory transmission stop function is required so that power transfer halts when a person enters an area that would exceed the controlled environment guideline value.

• Interference coordination: Because the 920 MHz band already hosts many existing users (RFID, active sensor systems, LPWA), the framework relies on an interference-coordination scheme publishing planned deployment information and coordinating with existing licensees where interference concerns are raised.

• Emission limits: The amendment specifies spurious/unwanted emission allowances for WPT specified low power stations within the Radio Equipment Regulations (無線設備規則).

What this means for manufacturers

1. A new, lower friction route to market for WPT transmitters. The ≤250 mW licence-free tier removes the individual station licence step, shortening deployment for products where per site licensing was previously uneconomic (appliances, mobile/embedded sensor power, consumer adjacent use).

2. Licence-free does not mean certification free. A specified low power WPT station is expected to require certified radio equipment (technical conformity certification / 技術基準適合証明, i.e. the Giteki mark) issued by an MIC-designated Registered Certification Body (RCB) before it can be placed on the market. Plan for equipment certification even where no station licence is needed.

3. Design in the transmit stop function early. RF exposure compliance is enforced through a required cut off when guideline field strength values would be exceeded. This is a functional safety design constraint, not a paperwork item, and should be specified at the hardware/firmware level.

4. Two product 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 given product targets before test planning, because the applicable technical conditions differ.

5. Coordination obligations sit with deployers, but affect product positioning. The interference coordination scheme (deployment disclosure and coordination with incumbent licensees) primarily binds installers/operators; manufacturers selling into Japan should be ready to support customers with the technical data those obligations require.

6. Existing indoor WPT installations are unaffected in their current use but can now be extended outdoors within premises once compliant with the new conditions.

   
   

Certification impact summary

Item	Before this amendment	After this amendment
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 certification via RCB	Still required (licence-free ≠ certification-free)
RF-exposure control	RF Protection Guidelines	RF Protection Guidelines + mandatory 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
Apr–Jul 2025	Council study of 920 MHz WPT outdoor-use technical conditions	Confirmed	Monitor draft technical conditions
22 Aug 2025	Public comment opened on draft Council report	Confirmed	—
17 Oct 2025	Public-comment results published	Confirmed	—
20 Oct 2025	Council partial report (答申) delivered to MIC	Confirmed	Begin product/roadmap planning for both tiers
June 2026	Implementing ordinance promulgated		Confirm final technical standards; scope test plans
On/after effective date	Outdoor-within-premises use + ≤250 mW licence-free tier available	Pending confirmation of effective date	Align certification (Giteki) and transmit-stop design; brief Japanese customers on coordination obligations