Electronic devices having millimeter wave ranging capabilities
An electronic device such as a wristwatch may be provided with a phased antenna array for conveying first signals at a first frequency between 10 GHz and 300 GHz and a non-millimeter wave antenna for conveying second signals at a second frequency below 10 GHz. The device may include conductive housing sidewalls and a display. Conductive structures in the display and the conductive housing sidewalls may define a slot element in the non-millimeter wave antenna. The phased antenna array may be mounted within the slot element, aligned with a spatial filter in the display, or aligned with a dielectric window in the conductive housing sidewalls. Control circuitry may process signals transmitted by the phased antenna array and a reflected version of the transmitted signals that has been received by the phased antenna array to detect a range between the device and an external object.
1. An electronic device, comprising:
a housing having conductive housing walls;
a display cover layer;
a display module that is overlapped by the display cover layer and that includes conductive display structures;
an antenna feed for an antenna having a first feed terminal coupled to the conductive display structures and a second feed terminal coupled to the conductive housing walls, wherein the conductive display structures and the conductive housing walls define edges of a slot element for the antenna; and
a phased antenna array mounted within the housing, wherein the antenna is configured to convey first radio-frequency signals at a first frequency below 10 GHz and the phased antenna array is configured to convey second radio-frequency signals at a second frequency between 10 GHz and 300 GHz.
2. The electronic device defined in claim 1 , wherein the phased antenna array is mounted within the slot element for the antenna and is configured to transmit the second radio-frequency signals through the display cover layer.
3. The electronic device defined in claim 2 , wherein the phased antenna array is at least partially embedded within the display cover layer.
4. The electronic device defined in claim 1 , wherein a dielectric window is formed in a given one of the conductive housing walls and the phased antenna array is configured to transmit the second radio-frequency signals through the dielectric window.
5. The electronic device defined in claim 4 , further comprising:
an additional phased antenna array mounted within the housing, wherein the additional phased antenna array is mounted within the slot element for the antenna.
6. The electronic device defined in claim 1 , further comprising:
a spatial filter in the conductive display structures, wherein the spatial filter has a pass band that includes the second frequency and the phased antenna array is configured to transmit the second radio-frequency signals through the display module via the spatial filter and through the display cover layer.
7. The electronic device defined in claim 6 , wherein a dielectric window is formed in a given one of the conductive housing walls, the electronic device further comprising:
an additional phased antenna array mounted within the housing, wherein the additional phased antenna array is configured to transmit third radio-frequency signals at a third frequency between 10 GHz and 300 GHz through the dielectric window.
8. The electronic device defined in claim 1 , further comprising:
a radio-frequency transceiver coupled to the antenna feed;
a transmitter and a receiver coupled to the phased antenna array, wherein the transmitter is configured to transmit the second radio-frequency signals and the receiver is configured to receive a reflected version of the second radio-frequency signals that is received by the phased antenna array; and
control circuitry configured to detect a range of an external object within a field of view of the phased antenna array with respect to the electronic device based on the transmitted second radio-frequency signals and the received reflected version of the second radio-frequency signals.
9. The electronic device defined in claim 8 , further comprising:
an accelerometer configured to generate motion data indicative of motion of the electronic device, wherein the control circuitry is configured to detect a predetermined spatial event based on the detected range and the motion data.
10. The electronic device defined in claim 8 , further comprising:
a switch having a first terminal coupled to the transmitter, a second terminal coupled to the receiver, and a third terminal coupled to the phased antenna array, wherein the switch is configured to couple a selected one of the transmitter and the receiver to the phased antenna array at a given time.
11. The electronic device defined in claim 1 , wherein the housing is configured to receive a wrist strap.
12. The electronic device defined in claim 11 , wherein the display cover layer and the display module form a touch screen, and the phased antenna array is configured to convey the second radio-frequency signals through the display cover layer of the touch screen.
13. The electronic device defined in claim 1 , wherein the phased antenna array has an elongated dimension that extends along an elongated dimension of the slot element.
14. The electronic device defined in claim 13 , wherein the phased antenna array comprises a one-dimensional array of antennas.