Wireless startup uBeam, a developer of wireless charging technology that uses ultrasound to transmit energy, has faced intense skepticism over its technology, despite having raised $23.4 million in venture capital from Silicon Valley luminaries including Andreessen Horowitz, Founders Fund, UpFront Ventures, Marissa Mayer and Mark Cuban. So the company revealed some details about its technology, which, as TechCrunch notes, relies on transmitters on a room's walls to track devices with uBeam receivers and send ultrasound beams at them. Then, the report notes, the receiver turns the vibrations of the sound into electricity, which charges a connected device.
To silence the skeptics, uBeam revealed it has "developed a high-powered air-coupled ultrasonic transducer to transmit and receive sound waves at a single frequency within the range of 45 kHz to 75 kHz with an output of 145dB to 155dB (or 316 W/m2 – 3kW/m2)," and can charge multiple devices simultaneously within a range of up to a 4-meter radius from a single transmitter. TechCrunch also notes that uBeam has filed for more than 30 patents and has six issued patents, but the crux of its technology is the transducer, which the firm thinks can deliver more power at the right frequency than any other. Article