What’s good for carpentry is also good for product design: have a well-defined set of requirements and plan your work before you start.
Here is a summary of the requirements we selected when we started our wireless power system design:
Safety. If it’s not safe, it’s not shipping. Safe enough for consumers to use, as defined by the applicable government and regulatory agencies.
Power. Enough to charge a phone. Keeping a phone running ‘forever’ requires delivering about 500mW of power to the phone. Anything beyond that can recharge the battery. So we wanted to deliver at least 500 mW to the phone, but more if possible. We chose the phone because it’s the most obvious use case for long-range wireless power.
Distance. At a minimum, deliver energy – enough to charge a phone – at room-sized distances.
Small receiver. Small enough to comfortably embed into phones or other smart devices.
Small transmitter. Small enough to be inconspicuous in a home and an office environment.
Easy to integrate. No custom antennas or other major engineering efforts required by our customers.
Support multiple devices. Able to support “one-to-many” charging scenarios beyond the “one-to-one” one.
Plug-and-play. No configuration required. No alignment required. Just turn it on and it works.
Plays nicely with others. Does not impact existing communication networks, TV remote controls or anything else that is reasonably going on in a home or office environment.
Energy-efficient. Does not consume more than a small light bulb.
Ability to charge moving objects. While many use cases have to do with fairly static objects, we wanted to keep the option of charging a device while moving.