Electronic device antennas
An electronic device such as a wristwatch may have a housing with metal portions such as metal sidewalls. The housing may form an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from a stack of capacitively coupled component layers such as a display layer, touch sensor layer, and near-field communications antenna layer at a front face of the device. An additional antenna may be formed from a peripheral resonating element that runs along a peripheral edge of the device and the antenna ground. A rear face antenna may be formed using a wireless power receiving coil as a radio-frequency antenna resonating element or may be formed from metal antenna traces on a plastic support for light-based components.
1. An electronic device, comprising:
a housing having a metal housing wall that forms at least part of an antenna ground for an antenna;
a display cover layer;
a stack of capacitively coupled electrical component layers that are overlapped by the display cover layer and that form an antenna resonating element for the antenna; and
an antenna feed for the antenna having a positive antenna feed terminal coupled to the stack of capacitively coupled electrical component layers and having a ground antenna feed terminal coupled to the antenna ground.
2. The electronic device defined in claim 1 wherein the stack of capacitively coupled electrical component layers comprises a display layer.
3. The electronic device defined in claim 2 wherein the stack of capacitively coupled electrical component layers comprises a touch sensor layer interposed between the display layer and the display cover layer.
4. The electronic device defined in claim 3 wherein the stack of capacitively coupled electrical component layers comprises a near-field communications antenna layer.
5. The electronic device defined in claim 4 wherein the display layer comprises an organic light-emitting diode display layer interposed between the near-field communications antenna layer and the touch sensor layer.
6. The electronic device defined in claim 5 further comprising near-field communications circuitry coupled to the near-field communications antenna layer.
7. The electronic device defined in claim 6 wherein the near-field communications antenna layer comprises loops of metal traces and wherein the near-field communications circuitry includes a printed circuit, a near-field communications transceiver on the printed circuit that is coupled to the loops of metal traces, and a metal shielding can that overlaps the near-field communications transceiver.
8. The electronic device defined in claim 7 wherein the positive antenna feed terminal is coupled to the metal shielding can.
9. The electronic device defined in claim 8 further comprising:
an additional printed circuit; and
a flexible printed circuit coupled between the printed circuit in the near-field communications circuitry and the additional printed circuit, wherein the additional printed circuit serves as an inductive path coupling the antenna resonating element to the ground.
10. The electronic device defined in claim 9 further comprising a battery between the additional printed circuit and the near-field communications antenna layer.
11. The electronic device defined in claim 10 further comprising radio-frequency transceiver circuitry coupled to the antenna that is configured to transmit and receive antenna signals at frequencies above 960 MHz using the antenna.
12. The electronic device defined in claim 1 further comprising radio-frequency transceiver circuitry coupled to the antenna that is configured to transmit and receive cellular telephone signals using the antenna.
13. The electronic device defined in claim 12 wherein the stack of capacitively coupled component layers comprise a display layer.
14. The electronic device defined in claim 13 further comprising a strap coupled to the housing.
15. An electronic device, comprising:
a structure that forms an antenna ground for an antenna;
a display that forms at least part of an antenna resonating element for the antenna; and
an antenna feed for the antenna having a positive antenna feed terminal coupled to the display and having a ground antenna feed terminal coupled to the antenna ground.
16. The electronic device defined in claim 15 further comprising:
a display cover layer that overlaps that display; and
a touch sensor that is capacitively coupled to the display and that forms part of the antenna resonating element.
17. The electronic device defined in claim 16 further comprising a near field communications layer that is capacitively coupled to the touch sensor and that forms part of the antenna resonating element.
18. The electronic device defined in claim 17 further comprising near-field communications circuitry having a shielding can, wherein the positive antenna feed is coupled to the display through the shielding can.
19. The electronic device defined in claim 18 further comprising metal spring fingers, wherein the shielding can has a portion that is coupled to the metal spring fingers.
20. An electronic device, comprising:
a housing having metal sidewalls that form at least part of an antenna ground for an antenna;
a display in the housing;
a display cover layer that overlaps the display;
a touch sensor that is interposed between the display and the display cover layer, wherein at least the touch sensor and the display are capacitively coupled and form an antenna resonating element for the antenna; and
cellular telephone transceiver circuitry configured to transmit and receive antenna signals using the antenna.