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Resonant Qi Transmitter Prototype - The Resonant Extension


The video show the prototype Tx demonstrated by Philips. It is a 3-coil Tx that can power any currently shipping Qi receiver at distance from 0 to 30 mm.

In the video you see the Tx transmit power through a 28 mm thick piece of wood, taken from an IKEA kitchen top. You also see it operate as a classic Qi transmitter with the receiver directly on top of the Tx.

The phones in the video are:

  • Nokia 920
  • Nexus 7
  • Nexus 5
  • iPhone 5 with sleeve

These phones and backcovers/sleeves were not modified. They operate as normal Qi v1.1 compliant receivers.


The resonant extension of the Qi specification has the following goals:

  1. Charge Qi phones over a distances up to 50 mm
  2. Charge multiple Qi phones concurrently using a single inverter