Apple has filed for a patent (number 9,761,927) for a “battery case with supplemental antenna features” for the iPhone. It involves a removable case for use with the smartphone.
In the patent filing, Apple says that some smartphone cases contain supplemental batteries. The company says it can be challenging to ensure that an electronic device antenna operates properly in the presence of an external case, as the materials of the case may affect antenna operation.
For example, metal structures associated with a battery of other components may interfere with the normal operation of an electronic device antenna and dielectric materials may load an antenna. If care isn’t taken, wireless performance for an electronic device may be degraded in the presence of a removable case or undesired amounts of radiated spurious emissions may arise. Apple says what’s need is an improved removable case for electronic devices.
Here’s Apple’s summary of the patent: “A male connector in the case may mate with a female connector in the device. A battery in the case may supply power to the device through the male connector. The electronic device may have an antenna. The case may have a supplemental antenna that compensates for variations in performance in the antenna when the device is received within the case. The supplemental antenna may be a parasitic antenna resonating element that is formed from metal traces on a flexible printed circuit. The flexible printed circuit, a metal trim structure, and a plastic support structure may form portions of a connector support structure in the case”
Of course, Apple files for — and is granted — lots of patents by the U.S. Patent & Trademark Office. Many are for inventions that never see the light of day. However, you never can tell which ones will materialize in a real product.