Wireless power transfer

A rectifier typically consists of diodes followed by a capacitor based low pass filter (LPF). A rectifier is a non linear circuit element, so its DC power output depends non linearly on the RF input power. The output DC power is influenced not only by the strength of the input RF signal but also by its waveform. For instance, signals with a high peak to average power ratio (PAPR) yield a higher DC power output for a given average incident RF power compared to constant-envelope signals. This is because the peaks of a high PAPR signal are more likely to exceed the diode turn on voltage, compared to a constant envelope signal with the same average power but lower peak power.

AirFuel Alliance RF standard

A standard that defines all procedures between the RF transmitter and receiver ensures interoperability between devices from different vendors, promoting the development of products utilizing RF power transfer technology.

AirFuel Alliance is a global coalition of companies that is developing standards for both near field (magnetic resonance) and far field (using RF wireless powering). The AirFuel Resonant standard, for devices using magnetic resonance, has already been adopted by commercial products. In January 2023, the AirFuel RF baseline system specification was published, and the AirFuel RF interoperability and conformance tests are currently in preparation for release. For a device to be certified by the AirFuel Alliance RF standard, it must satisfy these test cases.

As an active member of the AirFuel Alliance, Rohde & Schwarz plays a pivotal role in advancing the AirFuel RF standard. We leverage our expertise as a test and measurement provider to contribute to the development of industry standards that will shape the future of wireless powering.

3GPP Ambient IoT

The 3rd Generation Partnership Project (3GPP) is a global organization that defines standards for telecommunications. Recognizing the requirements of new IoT applications, such as battery less devices, 3GPP has introduced a new technology category called Ambient IoT.

The number of connections and device density in an Ambient IoT network can be orders of magnitude higher than existing 3GPP IoT technologies. At the same time, the complexity, energy storage capacity, power consumption and network coverage of Ambient IoT devices are orders of magnitude lower than existing 3GPP low power wide area (LPWA) technologies. The low power needs of Ambient IoT devices make RF signals a promising energy source.

"I want to thank Rohde & Schwarz for their leadership in developing a wireless power tester (WPT) for the AirFuel RF standard. The WPT will enable companies to test and validate conformance to the AirFuel RF standard and accelerate the deployment of interoperable RF wireless power solutions."
_{Dr. Sanjay Gupta, President and Chairman of AirFuel Alliance}