Electronic devices with wireless charging antenna arrays

An electronic device configured to wirelessly transfer power to an external device, the electronic device comprising:

• a housing;
• wireless power transfer circuitry in the housing;
• a cavity formed in the housing;
• a cover layer positioned over the cavity;
• a plurality of antennas within the cavity, wherein at least one antenna in the plurality of antennas is configured to transmit wireless charging signals at a transmit frequency from the wireless power transfer circuitry to the external device through the cover layer while the external device is on the cover layer, the transmit frequency being greater than 1 GHz, wherein the plurality of antennas in the cavity comprises an array of patch antennas;
• and
• control circuitry coupled to the wireless power transfer circuitry, wherein the control circuitry is configured to:
• select a patch antenna in the array to transmit the wireless charging signals to the external device, and
• disable a ring of patch antennas around the selected patch antenna in the array to form a guard ring structure for the selected patch antenna, wherein the guard ring structure is configured to block at least some of the wireless charging signals at the transmit frequency.

An electronic device configured to provide wireless power to an external device that is placed on the electronic device, the electronic device comprising:

• wireless power transfer circuitry that is configured to generate wireless charging signals;
• a plurality of antennas operatively coupled to the wireless power transfer circuitry;
• and
• control circuitry coupled to the wireless power transfer circuitry, wherein the control circuitry is configured to control the wireless power transfer circuitry to transmit the wireless charging signals over a selected antenna of the plurality of antennas, wherein the control circuitry is configured to control a set of antennas in the plurality of antennas that is adjacent to the selected antenna to form a filter, and wherein the filter is configured to block at least some of the transmitted wireless charging signals from being transmitted past the set of antennas.