The USPTO has published a patent application by three Intel engineers that describes an NFC antenna design which makes use of a cascaded coil concept to enable interactions to be performed without a user needing to precisely orientate their phone.
“A device may include a cascaded coil antenna to include a first coil antenna that is connected in series with a second coil antenna,” they explain in the application titled Cascaded Coils for Multi-surface Coverage in Near Field Communication.
“The first and second coil antennas are independent antennas prior to cascading and are located in different surfaces of the device to establish near field coupling through front side, top side, bottom side, or corner side of the portable device.
“The two coil antennas of the cascaded coil antenna are separate and independent from one another if not for the connecting wire that completes the cascading. In other words, they can be placed separately at any surface of the portable device.”
This is the third patent application published in recent weeks to address the issue of NFC antenna design. In May, an Apple patent application described a way to enable NFC signals to be transmitted from both the top and bottom of a mobile phone. Earlier this month, a Broadcom patent application set out a way to build multiple antennas into a single NFC device.