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JD: What do you feel consumers are really looking for from wireless power transfer (WPT) technologies?

HZ: This question really has a couple of parts: what the consumers want and what the consumers will end up using/needing. To answer the “want” question, we have to look at the actual problems with our devices. First, cell phones require that users remember to charge their devices. In that process, users have to use some type of charger near a wall socket. None of today’s available WPT technologies address these two core problems, and users are voting with their wallets. The “need” presents a larger wireless-power challenge for all the other devices and sensors we have in our life: remote controls, digital cameras, wireless keyboards and mice, tablets, game controllers, motion sensors, and smoke detectors—to name a few.

Due to their distribution in our environments and their quantities, we need a radical new solution that can address the power needs of these devices. When we solve this challenge, we will open the door for a truly wireless world that enables all of the intriguing designs of what we call the “Internet of Things.” In short, people will stop thinking of their devices’ batteries and start thinking of unrestricted use of their devices instead.

Hatem Zeine

JD: Which frequency ranges do you think are the most viable for WPT implementations now and in the future?

HZ: The different use cases of WPT will demand different spectrum sections for us—especially when we consider loss of energy in transmission. Medium- (>20-W) to high-power (>1-kW)  applications will inevitably need frequencies that are not absorbed by human flesh, as a mere 5% of power loss could amount to 700 W of power when charging an electric vehicle. This restricts WPT to frequencies below 50 MHz. The caveat of using such frequencies is that the energy cannot be focused at a distance, due to the long wavelength used in lieu of basketball-field-sized chargers. Low (<5-W) power applications, such as cell phones, can leverage the same frequencies (<50 MHz). But they would restrict the charging distance to a charging pad. Remote power delivery will require a wavelength that can be focused with small transmitters.

In addition, the power will have to be focused to a small (device-sized) region. Such wavelengths need to be a minimum of 1 in. to a maximum of 12 in., resulting in frequencies ranging from ~1 to ~12 GHz (give or take a few). Our remote wireless power uses the 2.4-GHz ISM band to deliver safe power at a distance of 30 ft.

JD: Why haven’t WPT chargers for mobile devices been more successful?

HZ: Currently, people do not view a WPT charger as a utility. Most people find that the WPT chargers available today do not change their habits or device usage. The added value is not obvious when having a phone with a WPT charging pad, as we still end up needing to remember to charge the device. And when it is charging, it is away from us. The device is not any better in terms of size/weight/design, so the user barely perceives the gain. Remember that all of the market-available WPT chargers power devices at a distance of no more than an inch from a pad that is connected to a wall power socket.

We believe that remote wireless charging will change our habits when users never have to charge their devices because they are receiving power all the time. The devices will then need smaller batteries, hence better designs and use.

JD: Do you feel that the main focus for WPT charging systems has been designed for a charging-pad approach?

HZ: The prevailing technology of wireless charging (which should be called “contactless charging”) has been inductive coupling, as seen by electric toothbrushes from the late 1960s and early 1970s. The more recent innovations in magnetic resonance have extended the range of coil-based WPT. But it has not liberated the device from the charger. What we are seeing today is the resurgence of coil-based technology in the marketplace, offering short-range power to devices without attaching contacts. It was simply the only option available.

JD: What major hurdles are faced by companies looking to implement a WPT system?

HZ: I think the biggest obstacle is having enough engineering “manpower” to help make their concept a reality and get to market. Because WPT is an emerging technology, new and innovative engineering techniques are required. Additionally, a real wireless-power solution, such as the one that Ossia has developed with Cota, requires many complex design elements to achieve all of the functionality desired by users. Examples include a 30-ft. charging distance, non-line-of-sight, efficiency, and being able to scale the technology to the next level. Finding engineers with the right RF experience is often challenging, so we are always looking for engineers with this type of background.  

JD: Is the major focus of WPT technologies on the commercial, industrial, or military sectors?

HZ: WPT serves all electronic devices, no matter what their application is. The most famous are smartphone chargers because there are so many smartphones and so much hassle with charging them. However, there are applications of wireless/contactless power transmission for industrial robotics, such as warehouse handheld scanners, that have just started being addressed. The tech companies supplying WPT will go where the money is. Where the smartphone market is concerned, it is really the 800-lb. gorilla in the room due to its fast churn and the vast financial resources that are available. We believe that our technologies will have a major impact on consumer devices as well as industrial sensors/controls, as both of these markets are reaching bottlenecks in technology advancement due to power availability.

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