PATENT DOCUMENT

Publication Number: US-10903566-B2
Application Number: US-201715718288-A
Country: US
Kind Code: B2

Title: Electronic device antennas for performing angle of arrival detection

Abstract:
An electronic device may be provided with wireless circuitry that includes antenna structures used to determine the position and orientation of the electronic device relative to external wireless equipment. The electronic device may include a housing having a planar conductive layer, a first slot antenna that includes a first bent slot element in the planar conductive layer, and a second slot antenna that includes a second bent slot element in the planar conductive layer. The first and second bent slot elements may be configured to receive radio-frequency signals at the same frequency. The first and second bent slot elements may have the same shape. The electronic device may include control circuitry configured to measure a phase difference between the radio-frequency signals received by the first and second slot antennas. The control circuitry may identify an angle of arrival of the received radio-frequency signals based on the measured phase difference.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a housing having a planar conductive layer; 
 a first slot antenna that includes a first bent slot element in the planar conductive layer and a first antenna feed coupled across the first bent slot elements wherein the first bent slot element is completely enclosed by the planar conductive layer; 
 
       and
 a second slot antenna that includes a second bent slot element in the planar conductive layer and a second antenna feed coupled across the second bent slot element, wherein the second bent slot element is completely enclosed by the planar conductive layer, the first and second bent slot elements are configured to receive radiofrequency signals at the same frequency, the first bent slot element has a first segment that extends along a longitudinal axis, and the second bent slot element has a second segment that extends along the longitudinal axis. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the first bent slot element has a third segment that extends away from the first segment perpendicular to the first segment and a fourth segment that extends away from the first segment perpendicular to the first segment and parallel to the third segment. 
     
     
       3. The electronic device defined in  claim 2 , wherein the second bent slot element has a fifth segment that extends away from the second segment perpendicular to the second segment and a sixth segment that extends away from the second segment perpendicular to the second segment and parallel to the fifth segment. 
     
     
       4. The electronic device defined in  claim 3 , wherein the first antenna feed is coupled across the third segment of the first bent slot element and the second antenna feed is coupled across a selected one of the fifth segment and the sixth segment of the second bent slot element. 
     
     
       5. The electronic device defined in  claim 3 , wherein the first, third, and fourth segments of the first bent slot element have a first total length that is approximately equal to half of an effective wavelength of the received radio-frequency signals and the second, fifth, and sixth segments of the second bent slot element have a second total length that is approximately equal to half of the effective wavelength of the received radio-frequency signals. 
     
     
       6. The electronic device defined in  claim 3 , further comprising:
 control circuitry configured to measure a phase difference between the radio-frequency signals received by the first and second slot antennas and configured to identify an angle of arrival of the received radio-frequency signals based on the measured phase difference. 
 
     
     
       7. The electronic device defined in  claim 6 , further comprising:
 an additional antenna configured to receive radio-frequency signals at the same frequency as the first and second slot antennas, wherein the control circuitry is further configured to identify the angle of arrival of the received radio-frequency signals based on the radio-frequency signals received by the additional antenna. 
 
     
     
       8. The electronic device defined in  claim 3 , wherein the first bent slot element is separated from the second bent slot element by a distance that is less than or equal to half of an effective wavelength of the received radio-frequency signals. 
     
     
       9. The electronic device defined in  claim 1 , further comprising:
 a dielectric substrate adjacent to the planar conductive layer that covers the first and second bent slot elements. 
 
     
     
       10. The electronic device defined in  claim 9 , further comprising:
 a shielding layer that covers the dielectric substrate and provides radio-frequency shielding for the first and second bent slot elements. 
 
     
     
       11. The electronic device defined in  claim 1 , wherein the housing includes a dielectric layer that covers the planar conductive layer and forms an exterior surface of the electronic device. 
     
     
       12. An electronic device configured to receive wireless signals from external wireless equipment, the electronic device comprising: a planar conductive layer;
 a first slot antenna that includes a first closed, U-shaped slot in the planar conductive layer and a first antenna feed coupled across the first closed U-shaped slot; 
 a second slot antenna that includes a second closed, U-shaped slot in the planar conductive layer and a second antenna feed coupled across the second closed, U-shaped dot, wherein the first and second dot antennas are configured to receive the wireless signals from the external wireless equipment; and 
 control circuitry configured to measure a phase difference between the wireless signals received by the first and second dot antennas and configured to identify an angle of arrival of the received wireless signals based on the measured phase difference. 
 
     
     
       13. The electronic device defined in  claim 12 , wherein the first closed, U-shaped slot has a first shape and a first size and the second closed, U-shaped slot has a second shape that is the same as the first shape and a second size that is the same as the first size. 
     
     
       14. The electronic device defined in  claim 12 , wherein the first and second slots are first and second U-shaped slots, respectively. 
     
     
       15. The electronic device defined in  claim 12 , further comprising:
 an additional antenna configured to convey radio-frequency signals in a wireless local area network band, wherein the control circuitry is further configured to identify an angle of arrival of the received wireless signals based on the wireless signals received by the additional antenna.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications circuitry. 
     Electronic devices often include wireless communications circuitry. For example, cellular telephones, computers, and other devices often contain antennas and wireless transceivers for supporting wireless communications. 
     It can be challenging to form electronic device antenna structures with desired attributes. In some wireless devices, antennas are bulky. In other devices, antennas are compact, but are sensitive to the position of the antennas relative to external objects. If care is not taken, antennas may become detuned, may emit wireless signals with a power that is more or less than desired, or may otherwise not perform as expected. 
     Some electronic devices perform location detection operations to detect the location of an external device based on an angle of arrival of signals received from the external device (using multiple antennas). If care is not taken, the antennas can introduce systematic phase error that makes it difficult to accurately estimate the angle of arrival. 
     It would therefore be desirable to be able to provide wireless circuitry for electronic devices having improved angle of arrival detection capabilities. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. The wireless circuitry may include antenna structures used to determine the position and orientation of the electronic device relative to external wireless equipment. The antenna structures may determine the position and orientation of the electronic device relative to external wireless equipment at least in part by measuring the angle of arrival of radio-frequency signals from the external wireless equipment. 
     The electronic device may include a housing having a planar conductive layer, a first slot antenna that includes a first bent slot element in the planar conductive layer and a first antenna feed coupled across the first bent slot element, and a second slot antenna that includes a second bent slot element in the planar conductive layer and a second antenna feed coupled across the second bent slot element. The first and second bent slot elements may be configured to receive radio-frequency signals at the same frequency. The first bent slot element may have a first segment that extends along a longitudinal axis and the second bent slot element may have a second segment that extends along the longitudinal axis. 
     The electronic device may also include control circuitry configured to measure a phase difference between the radio-frequency signals received by the first and second slot antennas. The control circuitry may identify an angle of arrival of the received radio-frequency signals based on the measured phase difference. The electronic device may include an additional antenna to obtain additional measurements for determining angle of arrival. 
     The antenna structures for measuring angle of arrival may be formed by first and second openings in a planar conductive layer, a first substrate formed in the first opening, a second substrate formed in the second opening, a first antenna resonating element for a first antenna formed on the first substrate, and a second antenna resonating element for a second antenna formed on the second substrate. The first antenna resonating element may have a first shape and the second antenna resonating element may have a second shape that is the same as the first shape. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of illustrative circuitry in an electronic device in accordance with an embodiment. 
         FIG. 3  is a diagram of illustrative wireless circuitry in accordance with an embodiment. 
         FIG. 4  is a diagram of an illustrative electronic device in wireless communication with an external node in a network in accordance with an embodiment. 
         FIG. 5  is a diagram showing how the location (e.g., range and angle of arrival) of an external node in a network may be determined relative to an electronic device in accordance with an embodiment. 
         FIG. 6  is a diagram showing how illustrative antenna structures in an electronic device may be used for detecting angle of arrival in accordance with an embodiment. 
         FIG. 7  is a diagram of an illustrative slot antenna in accordance with an embodiment. 
         FIG. 8  is a top view of an illustrative electronic device having multiple horizontal slot antennas for measuring angle of arrival in accordance with an embodiment. 
         FIG. 9  is a top view of an illustrative electronic device having multiple vertical slot antennas for measuring angle of arrival in accordance with an embodiment. 
         FIG. 10  is a top view of an illustrative electronic device having multiple bent slot antennas (e.g., “U” shaped or folded slot antennas) for measuring angle of arrival in accordance with an embodiment. 
         FIG. 11  is a cross-sectional side view showing illustrative antenna structures of the type shown in  FIG. 10  in accordance with an embodiment. 
         FIG. 12  is a top view of an illustrative electronic device having multiple multi-branch antennas for measuring angle of arrival in accordance with an embodiment. 
         FIG. 13  is a cross-sectional side view showing illustrative antenna structures of the type shown in  FIG. 12  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as electronic device  10  of  FIG. 1  may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in multiple wireless communications bands. 
     The wireless communications circuitry may include one more antennas. The antennas of the wireless communications circuitry can include loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. Conductive structures for the antennas may, if desired, be formed from conductive electronic device structures. 
     The conductive electronic device structures may include conductive housing structures. The housing structures may include peripheral structures such as peripheral conductive structures that run around the periphery of an electronic device. The peripheral conductive structures may serve as a bezel for a planar structure such as a display, may serve as sidewall structures for a device housing, may have portions that extend upwards from an integral planar rear housing (e.g., to form vertical planar sidewalls or curved sidewalls), and/or may form other housing structures. 
     Gaps may be formed in the peripheral conductive structures that divide the peripheral conductive structures into peripheral segments. One or more of the segments may be used in forming one or more antennas for electronic device  10 . Antennas may also be formed using an antenna ground plane and/or an antenna resonating element formed from conductive housing structures (e.g., internal and/or external structures, support plate structures, etc.). 
     Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, or other suitable electronic equipment. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may be mounted on the front face of device  10 . Display  14  may be a touch screen that incorporates capacitive touch electrodes or may be insensitive to touch. The rear face of housing  12  (i.e., the face of device  10  opposing the front face of device  10 ) may have a planar housing wall. The rear housing wall may have slots that pass entirely through the rear housing wall and that therefore separate housing wall portions (and/or sidewall portions) of housing  12  from each other. The rear housing wall may include conductive portions and/or dielectric portions. If desired, the rear housing wall may include a planar metal layer covered by a thin layer or coating of dielectric such as glass, plastic, sapphire, or ceramic. Housing  12  (e.g., the rear housing wall, sidewalls, etc.) may also have shallow grooves that do not pass entirely through housing  12 . The slots and grooves may be filled with plastic or other dielectric. If desired, portions of housing  12  that have been separated from each other (e.g., by a through slot) may be joined by internal conductive structures (e.g., sheet metal or other metal members that bridge the slot). 
     Display  14  may include pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, liquid crystal display (LCD) components, or other suitable pixel structures. A display cover layer such as a layer of clear glass or plastic may cover the surface of display  14  or the outermost layer of display  14  may be formed from a color filter layer, thin-film transistor layer, or other display layer. Buttons such as button  24  may pass through openings in the cover layer if desired. The cover layer may also have other openings such as an opening for speaker port  26 . 
     Housing  12  may include peripheral housing structures such as structures  16  (sometimes referred to herein as peripheral housing structures, peripheral conductive housing structures, or peripheral structures). Structures  16  may run around the periphery of device  10  and display  14 . In configurations in which device  10  and display  14  have a rectangular shape with four edges, structures  16  may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges (as an example). Peripheral structures  16  or part of peripheral structures  16  may serve as a bezel for display  14  (e.g., a cosmetic trim that surrounds all four sides of display  14  and/or that helps hold display  14  to device  10 ). Peripheral structures  16  may, if desired, form sidewall structures for device  10  (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.). 
     Peripheral housing structures  16  may be formed of a conductive material such as metal and may therefore sometimes be referred to as peripheral conductive housing structures, conductive housing structures, peripheral metal structures, or a peripheral conductive housing member (as examples). Peripheral housing structures  16  may be formed from a metal such as stainless steel, aluminum, or other suitable materials. One, two, or more than two separate structures may be used in forming peripheral housing structures  16 . 
     It is not necessary for peripheral housing structures  16  to have a uniform cross-section. For example, the top portion of peripheral housing structures  16  may, if desired, have an inwardly protruding lip that helps hold display  14  in place. The bottom portion of peripheral housing structures  16  may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). Peripheral housing structures  16  may have substantially straight vertical sidewalls, may have sidewalls that are curved, or may have other suitable shapes. In some configurations (e.g., when peripheral housing structures  16  serve as a bezel for display  14 ), peripheral housing structures  16  may run around the lip of housing  12  (i.e., peripheral housing structures  16  may cover only the edge of housing  12  that surrounds display  14  and not the rest of the sidewalls of housing  12 ). 
     If desired, housing  12  may have a conductive rear surface or wall. For example, housing  12  may be formed from a metal such as stainless steel or aluminum. The rear surface of housing  12  may lie in a plane that is parallel to display  14 . In configurations for device  10  in which the rear surface of housing  12  is formed from metal, it may be desirable to form parts of peripheral conductive housing structures  16  as integral portions of the housing structures forming the rear surface of housing  12 . For example, a rear housing wall of device  10  may be formed from a planar metal structure and portions of peripheral housing structures  16  on the sides of housing  12  may be formed as flat or curved vertically extending integral metal portions of the planar metal structure. Housing structures such as these may, if desired, be machined from a block of metal and/or may include multiple metal pieces that are assembled together to form housing  12 . The planar rear wall of housing  12  may have one or more, two or more, or three or more portions. Peripheral conductive housing structures  16  and/or the conductive rear wall of housing  12  may form one or more exterior surfaces of device  10  (e.g., surfaces that are visible to a user of device  10 ) and/or may be implemented using internal structures that do not form exterior surfaces of device  10  (e.g., conductive housing structures that are not visible to a user of device  10  such as conductive structures that are covered with layers such as thin cosmetic layers, protective coatings, and/or other coating layers that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide structures  16  from view of the user). 
     Display  14  may have an array of pixels that form an active area AA that displays images for a user of device  10 . An inactive border region such as inactive area IA may run along one or more of the peripheral edges of active area AA. 
     Display  14  may include conductive structures such as an array of capacitive electrodes for a touch sensor, conductive lines for addressing pixels, driver circuits, etc. Housing  12  may include internal conductive structures such as metal frame members and a planar conductive housing member (sometimes referred to as a backplate) that spans the walls of housing  12  (i.e., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of member  16 ). The backplate may form an exterior rear surface of device  10  or may be covered by layers such as thin cosmetic layers, protective coatings, and/or other coatings that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide the backplate from view of the user. Device  10  may also include conductive structures such as printed circuit boards, components mounted on printed circuit boards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device  10 , may extend under active area AA of display  14 , for example. 
     In regions  22  and  20 , openings may be formed within the conductive structures of device  10  (e.g., between peripheral conductive housing structures  16  and opposing conductive ground structures such as conductive portions of housing  12 , conductive traces on a printed circuit board, conductive electrical components in display  14 , etc.). These openings, which may sometimes be referred to as gaps, may be filled with air, plastic, and/or other dielectrics and may be used in forming slot antenna resonating elements for one or more antennas in device  10 , if desired. 
     Conductive housing structures and other conductive structures in device  10  may serve as a ground plane for the antennas in device  10 . The openings in regions  20  and  22  may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element from the ground plane, may contribute to the performance of a parasitic antenna resonating element, or may otherwise serve as part of antenna structures formed in regions  20  and  22 . If desired, the ground plane that is under active area AA of display  14  and/or other metal structures in device  10  may have portions that extend into parts of the ends of device  10  (e.g., the ground may extend towards the dielectric-filled openings in regions  20  and  22 ), thereby narrowing the slots in regions  20  and  22 . 
     In general, device  10  may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device  10  may be located at opposing first and second ends of an elongated device housing (e.g., at ends  20  and  22  of device  10  of  FIG. 1 ), along one or more edges of a device housing, in the center of a device housing, in other suitable locations, or in one or more of these locations. The arrangement of  FIG. 1  is merely illustrative. 
     Portions of peripheral housing structures  16  may be provided with peripheral gap structures. For example, peripheral conductive housing structures  16  may be provided with one or more peripheral gaps such as gaps  18 , as shown in  FIG. 1 . The gaps in peripheral housing structures  16  may be filled with dielectric such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. Gaps  18  may divide peripheral housing structures  16  into one or more peripheral conductive segments. There may be, for example, two peripheral conductive segments in peripheral housing structures  16  (e.g., in an arrangement with two of gaps  18 ), three peripheral conductive segments (e.g., in an arrangement with three of gaps  18 ), four peripheral conductive segments (e.g., in an arrangement with four of gaps  18 , etc.). The segments of peripheral conductive housing structures  16  that are formed in this way may form parts of antennas in device  10 . 
     If desired, openings in housing  12  such as grooves that extend partway or completely through housing  12  may extend across the width of the rear wall of housing  12  and may penetrate through the rear wall of housing  12  to divide the rear wall into different portions. These grooves may also extend into peripheral housing structures  16  and may form antenna slots, gaps  18 , and other structures in device  10 . Polymer or other dielectric may fill these grooves and other housing openings. In some situations, housing openings that form antenna slots and other structure may be filled with a dielectric such as air. 
     In a typical scenario, device  10  may have one or more upper antennas and one or more lower antennas (as an example). An upper antenna may, for example, be formed at the upper end of device  10  in region  22 . A lower antenna may, for example, be formed at the lower end of device  10  in region  20 . The antennas may be used separately to cover identical communications bands, overlapping communications bands, or separate communications bands. The antennas may be used to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme. 
     Antennas in device  10  may be used to support any communications bands of interest. For example, device  10  may include antenna structures for supporting local area network communications, voice and data cellular telephone communications, global positioning system (GPS) communications or other satellite navigation system communications, Bluetooth® communications, etc. 
     A schematic diagram showing illustrative components that may be used in device  10  of  FIG. 1  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include control circuitry such as storage and processing circuitry  28  (sometimes referred to herein as control circuitry  28  or circuitry  28 ). Storage and processing circuitry  28  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, etc. 
     Storage and processing circuitry  28  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, storage and processing circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, multiple-input and multiple-output (MIMO) protocols, antenna diversity protocols, satellite navigation system protocols, millimeter wave communications protocols, IEEE 802.15.4 ultra-wideband communications protocols, etc. 
     Input-output circuitry  30  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, position and orientation sensors (e.g., sensors such as accelerometers, gyroscopes, and compasses), capacitance sensors, proximity sensors (e.g., capacitive proximity sensors, light-based proximity sensors, etc.), fingerprint sensors (e.g., a fingerprint sensor integrated with a button such as button  24  of  FIG. 1  or a fingerprint sensor that takes the place of button  24 ), etc. 
     Input-output circuitry  30  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling various radio-frequency communications bands. For example, radio-frequency transceiver circuitry  90  may include transceiver circuitry  36 ,  38 ,  42 ,  44 , and  46 . Transceiver circuitry  36  may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communications in frequency ranges such as a low communications band from 700 to 960 MHz, a low-midband from 960 to 1710 MHz, a midband from 1710 to 2170 MHz, a high band from 2300 to 2700 MHz, an ultra-high band from 3400 to 3700 MHz or other communications bands between 600 MHz and 4000 MHz or other suitable frequencies (as examples). 
     Circuitry  38  may handle voice data and non-voice data. Wireless communications circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  34  may include circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc. Wireless communications circuitry  34  may include global positioning system (GPS) receiver equipment such as GPS receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data. In WiFi® and Bluetooth® links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. 
     Millimeter wave transceiver circuitry  44  (sometimes referred to as extremely high frequency (EHF) transceiver circuitry  44  or transceiver circuitry  44 ) may support communications at frequencies between about 10 GHz and 300 GHz. For example, transceiver circuitry  44  may support communications in Extremely High Frequency (EHF) or millimeter wave communications bands between about 30 GHz and 300 GHz and/or in centimeter wave communications bands between about 10 GHz and 30 GHz (sometimes referred to as Super High Frequency (SHF) bands). As examples, transceiver circuitry  44  may support communications in an IEEE K communications band between about 18 GHz and 27 GHz, a K a  communications band between about 26.5 GHz and 40 GHz, a K u  communications band between about 12 GHz and 18 GHz, a V communications band between about 40 GHz and 75 GHz, a W communications band between about 75 GHz and 110 GHz, or any other desired frequency band between approximately 10 GHz and 300 GHz. If desired, circuitry  44  may support IEEE 802.11ad communications at 60 GHz and/or 5 th  generation mobile networks or 5 th  generation wireless systems (5G) communications bands between 27 GHz and 90 GHz. If desired, circuitry  28  may support communications at multiple frequency bands between 10 GHz and 300 GHz such as a first band from 27.5 GHz to 28.5 GHz, a second band from 37 GHz to 41 GHz, and a third band from 57 GHz to 71 GHz, or other communications bands between 10 GHz and 300 GHz. Circuitry  44  may be formed from one or more integrated circuits (e.g., multiple integrated circuits mounted on a common printed circuit in a system-in-package device, one or more integrated circuits mounted on different substrates, etc.). While circuitry  44  is sometimes referred to herein as millimeter wave transceiver circuitry  44 , millimeter wave transceiver circuitry  44  may handle communications at any desired communications bands at frequencies between 10 GHz and 300 GHz (e.g., in millimeter wave communications bands, centimeter wave communications bands, etc.). 
     Ultra-wideband transceiver circuitry  46  may support communications using the IEEE 802.15.4 protocol and/or other wireless communications protocols. Ultra-wideband wireless signals may be based on an impulse radio signaling scheme that uses band-limited data pulses. Ultra-wideband signals may have any desired bandwidths such as bandwidths between 499 MHz and 1331 MHz, bandwidths greater than 500 MHz, etc. The presence of lower frequencies in the baseband may sometimes allow ultra-wideband signals to penetrate through objects such as walls. In an IEEE 802.15.4 system, a pair of electronic devices may exchange wireless time stamped messages. Time stamps in the messages may be analyzed to determine the time of flight of the messages and thereby determine the distance (range) between the devices and/or an angle between the devices. Transceiver circuitry  46  may operate in a 6.5 GHz frequency band, an 8 GHz frequency band, between 3.1 GHz and 10.6 GHz, and/or at other suitable frequencies. 
     Wireless communications circuitry  34  may include antennas  40 . Antennas  40  in wireless communications circuitry  34  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from stacked patch antenna structures, loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, monopoles, dipoles, helical antenna structures, Yagi (Yagi-Uda) antenna structures, hybrids of these designs, etc. If desired, one or more of antennas  40  may be cavity-backed antennas. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link antenna. Dedicated antennas may be used for receiving satellite navigation system signals or, if desired, antennas  40  can be configured to receive both satellite navigation system signals and signals for other communications bands (e.g., wireless local area network signals and/or cellular telephone signals). Antennas  40  can include two or more antennas for handling ultra-wideband wireless communication. 
     Transmission line paths may be used to route antenna signals within device  10 . For example, transmission line paths may be used to couple antenna structures  40  to transceiver circuitry  90 . Transmission lines in device  10  may include coaxial probes realized by metalized vias, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, transmission lines formed from combinations of transmission lines of these types, etc. Transmission lines in device  10  may be integrated into rigid and/or flexible printed circuit boards. In one suitable arrangement, transmission lines in device  10  may also include transmission line conductors (e.g., signal and ground conductors) integrated within multilayer laminated structures (e.g., layers of a conductive material such as copper and a dielectric material such as a resin that are laminated together without intervening adhesive) that may be folded or bent in multiple dimensions (e.g., two or three dimensions) and that maintain a bent or folded shape after bending (e.g., the multilayer laminated structures may be folded into a particular three-dimensional shape to route around other device components and may be rigid enough to hold its shape after folding without being held in place by stiffeners or other structures). All of the multiple layers of the laminated structures may be batch laminated together (e.g., in a single pressing process) without adhesive (e.g., as opposed to performing multiple pressing processes to laminate multiple layers together with adhesive). Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired. 
     A schematic diagram of an antenna  40  coupled to transceiver circuitry  90  (e.g., transceiver circuitry  46 ) is shown in  FIG. 3 . As shown in  FIG. 3 , radio-frequency transceiver circuitry  90  may be coupled to antenna feed  100  of antenna  40  using transmission line  64 . Antenna feed  100  may include a positive antenna feed terminal such as positive antenna feed terminal  96  and may include a ground antenna feed terminal such as ground antenna feed terminal  98 . Transmission line  64  may be formed from metal traces on a printed circuit or other conductive structures and may have a positive transmission line signal path such as path  91  that is coupled to terminal  96  and a ground transmission line signal path such as path  94  that is coupled to terminal  98 . Transmission line paths such as path  64  may be used to route antenna signals within device  10 . For example, transmission line paths may be used to couple antenna structures such as one or more antennas to transceiver circuitry  90 . Transmission lines in device  10  may include coaxial probes realized by metal vias, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, transmission lines formed from combinations of transmission lines of these types, etc. In one suitable arrangement, transmission lines in device  10  may also include transmission line conductors (e.g., signal and ground conductors) integrated within multilayer laminated structures (e.g., layers of a conductive material such as copper and a dielectric material such as a resin that are laminated together without intervening adhesive) that may be folded or bent in multiple dimensions (e.g., two or three dimensions) and that maintain a bent or folded shape after bending (e.g., the multilayer laminated structures may be folded into a particular three-dimensional shape to route around other device components and may be rigid enough to hold its shape after folding without being held in place by stiffeners or other structures). Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within transmission line  64  and/or circuits such as these may be incorporated into antenna  40  if desired (e.g., to support antenna tuning, to support operation in desired frequency bands, etc.). 
     During operation, electronic device  10  may communicate with external wireless equipment. If desired, electronic device  10  may use radio-frequency signals conveyed between electronic device  10  and the external wireless equipment to identify a location of the external wireless equipment relative to electronic device  10 . Device  10  may identify the relative location of the external wireless equipment by identifying a range to the external wireless equipment (e.g., the distance between the external equipment and device  10 ) and the angle of arrival (AoA) of signals from external wireless equipment (e.g., the angle at which wireless signals are received from the external wireless equipment).  FIG. 4  is a diagram showing how electronic device  10  may determine a distance D between the electronic device  10  and external wireless equipment such as wireless network node  78  (sometimes referred to herein as wireless equipment  78 , wireless device  78 , external device  78 , or external equipment  78 ). 
     Node  78  may include devices that are capable of receiving and/or transmitting wireless signals such as signals  58 . Node  78  may include tagged devices (e.g., any suitable object that has been provided with a wireless receiver and/or a wireless transmitter), electronic equipment (e.g., an infrastructure-related device), and/or other electronic devices (e.g., devices of the type described in connection with  FIG. 2 , including some or all of the same wireless communications capabilities as device  10 ). For example, node  78  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, headset device (e.g., virtual or augmented reality headset devices), or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Node  78  may also be a set-top box, a camera device with wireless communications capabilities, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, or other suitable electronic equipment. Node  78  may also be a key fob, a wallet, a book, a pen, or other object that has been provided with a low-power transmitter (e.g., an RFID transmitter or other transmitter). Node  78  may be electronic equipment such as a thermostat, a smoke detector, a Bluetooth® Low Energy (Bluetooth LE) beacon, a WiFi® wireless access point, a wireless base station, a server, a heating, ventilation, and air conditioning (HVAC) system (sometimes referred to as a temperature-control system), a light source such as a light-emitting diode (LED) bulb, a light switch, a power outlet, an occupancy detector (e.g., an active or passive infrared light detector, a microwave detector, etc.), a door sensor, a moisture sensor, an electronic door lock, a security camera, or other device. 
     Device  10  may communicate with node  78  using wireless signals  58 . Wireless signals  58  may include Bluetooth® signals, near-field communications signals, wireless local area network signals such as IEEE 802.11 signals, millimeter wave communication signals such as signals at 60 GHz, ultra-wideband radio frequency signals, other radio-frequency wireless signals, infrared signals, etc. Wireless signals  58  may be used to determine and/or convey information such as location and orientation information. For example, control circuitry  28  in device  10  may determine the location of node  78  relative to device  10  using wireless signals  58 . 
     In arrangements where node  78  is capable of sending or receiving communications signals, control circuitry  28  may determine distance D using wireless signals (e.g., signals  58  of  FIG. 4 ). Control circuitry  28  may determine distance D using signal strength measurement schemes (e.g., measuring the signal strength of radio signals from node  78 ) or using time based measurement schemes such as time of flight measurement techniques, time difference of arrival measurement techniques, angle of arrival measurement techniques, triangulation methods, time-of-flight methods, using a crowdsourced location database, and other suitable measurement techniques. This is merely illustrative, however. If desired, control circuitry  28  may use information from Global Positioning System receiver circuitry  42 , proximity sensors (e.g., infrared proximity sensors or other proximity sensors), image data from a camera, motion sensor data from motion sensors, and/or using other circuitry in device  10  to help determine distance D. 
     In addition to determining the distance D between device  10  and node  78 , control circuitry  28  may be configured to determine the orientation of device  10  relative to node  78 .  FIG. 5  illustrates how the position and orientation of device  10  relative to nearby nodes such as node  78  may be determined. If desired, control circuitry  28  may use a horizontal coordinate system to determine the location and orientation of device  10  relative to node  78 . In this type of coordinate system, control circuitry  28  may determine an azimuth angle θ and/or an elevation angle φ to describe the position of nearby nodes  78  relative to device  10 . Control circuitry  28  may define a reference plane such as local horizon  162  and a reference vector such as reference vector  164 . Local horizon  162  may be a plane that intersects device  10  and that is defined relative to a surface of device  10 . For example, local horizon  162  may be a plane that is parallel to or coplanar with display  14  of device  10 . Reference vector  164  (sometimes referred to as the “north” direction) may be a vector in local horizon  162 . If desired, reference vector  164  may be aligned with longitudinal axis  102  of device  10  (e.g., an axis running lengthwise down the center of device  10 ). When reference vector  164  is aligned with longitudinal axis  102  of device  10 , reference vector  164  may correspond to the direction in which device  10  is being pointed. 
     Azimuth angle θ and elevation angle φ may be measured relative to local horizon  162  and reference vector  164 . As shown in  FIG. 5 , the elevation angle φ (sometimes referred to as altitude) of node  78  is the angle between node  78  and local horizon  162  of device  10  (e.g., the angle between vector  166  extending between device  10  and node  78  and a coplanar vector  168  extending between device  10  and horizon  162 ). The azimuth angle θ of node  78  is the angle of node  78  around local horizon  162  (e.g., the angle between reference vector  164  and vector  168 ). In the example of  FIG. 5 , the azimuth angle θ and elevation angle φ of node  78  are greater than 0°. 
     If desired, other axes besides longitudinal axis  102  may be used as reference vector  164 . For example, control circuitry  28  may use a horizontal axis that is perpendicular to longitudinal axis  102  as reference vector  164 . This may be useful in determining when nodes  78  are located next to a side portion of device  10  (e.g., when device  10  is oriented side-to-side with one of nodes  78 ). 
     After determining the orientation of device  10  relative to node  78 , control circuitry  28  may take suitable action. For example, control circuitry  28  may send information to node  78 , may request and/or receive information from  78 , may use display  14  to display a visual indication of wireless pairing with node  78 , may use speakers to generate an audio indication of wireless pairing with node  78 , may use a vibrator, a haptic actuator, or other mechanical element to generate haptic output indicating wireless pairing with node  78 , may use display  14  to display a visual indication of the location of node  78  relative to device  10 , may use speakers to generate an audio indication of the location of node  78 , may use a vibrator, a haptic actuator, or other mechanical element to generate haptic output indicating the location of node  78  and/or may take other suitable action. 
     In one suitable arrangement, electronic device may determine the distance between the electronic device  10  and node  78  and the orientation of electronic device  10  relative to node  78  using two or more ultra-wideband antennas. The ultra-wide band antennas may receive wireless communication signals from node  78 . Time stamps in the wireless communication signals may be analyzed to determine the time of flight of the wireless communication signals and thereby determine the distance (range) between electronic device  10  and node  78 . Additionally, angle of arrival (AoA) measurement techniques may be used to determine the orientation of electronic device  10  relative to node  78 . In angle of arrival measurement, node  78  transmits a wireless signal to electronic device  10 . Electronic device  10  measures a delay in arrival time of the wireless communication signal between the two or more ultra-wideband antennas. The delay in arrival time (e.g., the difference in received phase at each ultra-wideband antenna) can be used to determine the angle of arrival of the wireless communication signal (and therefore the angle of node  78  relative to electronic device  10 ). Once distance D and the angle of arrival have been determined, device  10  may have knowledge of the precise location of node  78  relative to device  10 . 
       FIG. 6  is a schematic diagram showing how angle of arrival measurement techniques may be used to determine the orientation of electronic device  10  relative to node  78 . As shown in  FIG. 6 , electronic device  10  may include multiple antennas (e.g., a first antenna  40 - 1  and a second antenna  40 - 2 ) coupled to transceiver circuitry  90  by respective transmission lines  64  (e.g., a first transmission line  64 - 1  and a second transmission line  64 - 2 ). Antennas  40 - 1  and  40 - 2  may each receive a wireless signal  58  from node  78 . Antennas  40 - 1  and  40 - 2  may be laterally separated by a distance d 1 , where antenna  40 - 1  is farther away from node  78  than  40 - 2  (in the example of  FIG. 6 ). Therefore, wireless communications signal  58  travels a greater distance to reach antenna  40 - 1  than  40 - 2 . The additional distance between node  78  and antenna  40 - 1  is shown in  FIG. 6  as distance d 2 .  FIG. 6  also shows angles x and y (where x+y=90°). 
     Distance d 2  may be determined as a function of angle φ or angle x (e.g., d 2 =d 1 *sin(x) or d 2 =d 1 *cos(y)). Distance d 2  may also be determined as a function of the phase difference between the signal received by antenna  40 - 1  and the signal received by antenna  40 - 2  (e.g., d 2 =Δϕ*λ(2*π), where Δϕ is the phase difference between the signal received by antenna  40 - 1  and the signal received by antenna  40 - 2  and λ is the wavelength of the received signal  58 ). Electronic device  10  may have phase measurement circuitry coupled to each antenna to measure the phase of the received signals and identify a difference in the phases (Δϕ). The two equations for d 2  may be set equal to each other (e.g., d 1 *sin(x)=Δϕ*λ(2*π) and rearranged to solve for the angle x (e.g., x=sin −1 (Δϕ*λ(2*π*d 1 )) or y. Therefore, the angle of arrival may be determined (e.g., by control circuitry  28 ) based on the known (predetermined) distance between antennas  40 - 1  and  40 - 2 , the detected (measured) phase difference between the signal received by antenna  40 - 1  and the signal received by antenna  40 - 2 , and the known wavelength (frequency) of the received signals  58 . 
     Distance d 1  may be selected to ease the calculation for phase difference between the signal received by antenna  40 - 1  and the signal received by antenna  40 - 2 . For example, d 1  may be less than or equal to one half of the wavelength (e.g., effective wavelength) of the received signal  58  (e.g., to avoid multiple phase difference solutions). 
     With two antennas for determining angle of arrival (as in  FIG. 6 ), the angle of arrival within a single plane may be determined. For example, antennas  40 - 1  and  40 - 2  in  FIG. 6  may be used to determine azimuth angle θ. A third antenna may be included to enable angle of arrival determination in multiple planes (e.g., azimuth angle θ and elevation angle φ may both be determined). 
     To improve the accuracy of angle of arrival determination using antennas  40 - 1  and  40 - 2 , it may be desirable for antennas  40 - 1  and  40 - 2  to have similar radiation patterns. Therefore, antennas  40 - 1  and  40 - 2  may have similar shapes and may convey signals with the same polarization if desired. Additionally, the accuracy of the angle of arrival determination may be optimized when antennas  40 - 1  and  40 - 2  are considered to operate as point sources (e.g., where the area spanned by the antenna radiating elements do not affect the phase difference measurement). Therefore, it may be desirable for antennas  40 - 1  and  40 - 2  to have as small an operating volume as possible. 
     In some arrangements, antennas  40 - 1  and  40 - 2  may be slot antennas that include one or more slot antenna elements. As shown in  FIG. 7 , for example, antenna  40  (e.g., a given one of antennas  40 - 1  or  40 - 2  of  FIG. 6 ) may be based on a slot antenna configuration having an opening such as slot  62  that is formed within conductive structures such as antenna ground  104 . In the configuration of  FIG. 7 , slot  62  is a closed slot, because portions of antenna ground  104  completely surround and enclose slot  62 . Antenna ground  104  may be formed from housing structures such as a conductive support plate, printed circuit traces, conductive portions of a display, metal portions of electronic components, or other conductive ground structures. Slot  62  may be filled with air, plastic, and/or other dielectric. The shape of slot  62  may be straight or may have one or more bends (e.g., slot  62  may have an elongated shape following a meandering path). The antenna feed for antenna  40  may include positive antenna feed terminal  96  and ground antenna feed terminal  98 . Feed terminals  96  and  98  may, for example, be located on opposing sides of slot  62  (e.g., on opposing long sides of slot  62 ). Slot  62  of  FIG. 7  (sometimes referred to herein as slot antenna resonating element  62 , slot resonating element  62 , or slot element  62 ) may give rise to an antenna resonance at frequencies around a center frequency in which the wavelength of operation of the antenna is approximately equal to the perimeter of the slot. In narrow slots, the length of the slot may be approximately equal to half of the corresponding wavelength of operation. Harmonic modes of slot  62  may also be configured to cover desired frequency bands. In scenarios where slot  62  is an open slot (e.g., by forming an opening in the right-hand or left-hand end of antenna ground  104  so that slot  62  protrudes through antenna ground  104 ), the length of slot  62  may be approximately equal to one quarter of the effective wavelength of operation of antenna  40 . If desired, the frequency response of antenna  40  can be tuned using one or more tunable components such as tunable inductors or tunable capacitors. These components may have terminals that are coupled to opposing sides of the slot (e.g., the tunable components may bridge the slot). If desired, tunable components may have terminals that are coupled to respective locations along the length of one of the sides of slot  62 . Combinations of these arrangements may also be used. 
     A top interior view of an illustrative portion of device  10  that contains antennas is shown in  FIG. 8 . As shown in  FIG. 8 , device  10  may have peripheral conductive housing structures such as peripheral conductive housing structures  16 . Peripheral conductive housing structures  16  may be divided by dielectric-filled peripheral gaps (e.g., plastic gaps)  18  such as gaps  18 - 1  and  18 - 2 . In some configurations, air and/or other dielectric may fill slot  101  between segment  108  of peripheral conductive housing structures  16  and ground structures  104 . In one suitable arrangement, ground  104  has portions formed from conductive portions of housing  12  (e.g., portions of a rear wall of housing  12  and portions of peripheral conductive housing structures  16  that are separated from segment  108  by peripheral gaps  18 - 1  and  18 - 2 ). Antenna ground  104  may also have portions formed by portions of display  14  (e.g., conductive portions of a display panel, a conductive plate for supporting the display panel, and/or a conductive frame for supporting the conductive plate and/or the display panel). 
     Ground  104  may serve as antenna ground for one or more antennas  40  (e.g., at least a first slot antenna  40 - 1  and a second slot antenna  40 - 2 ). For example, slot antenna  40 - 1  may include a slot element  62 - 1  in ground  104 , whereas slot antenna  40 - 2  may include a slot element  62 - 2  in ground  104 . Slots  62 - 1  and  62 - 2  in antenna ground  104  may be filled with air, plastic, and/or other dielectric. Antenna  40 - 1  may be fed using antenna feed  100 - 1  having positive antenna feed terminal  96 - 1  coupled to a first side of slot  62 - 1  and ground antenna feed terminal  98 - 1  coupled to a second side of slot  62 - 1 . Antenna  40 - 2  may be fed using antenna feed  100 - 2  having positive antenna feed terminal  96 - 2  coupled to a first side of slot  62 - 2  and ground antenna feed terminal  98 - 2  coupled to a second side of slot  62 - 2 . Slot  62 - 1  may have a length  68 - 1  that is selected to be approximately equal to (e.g., within 15% of) half of the effective wavelength of operation of antennas  40 - 1  and  40 - 2 . The effective wavelength of operation may take into account dielectric loading introduced by dielectric materials surrounding the antennas. In general, dielectric loading reduces the wavelength compared to free space. Slot  62 - 2  may have the same length as slot  62 - 1 . Electronic device  10  may be characterized by longitudinal axis  282 . Length  68 - 1  may extend perpendicular to longitudinal axis  282  (and the Y-axis of  FIG. 8 ). 
     If desired, additional antenna structures such as antenna structures  40 ′ may be included in electronic device  10 . Antennas  40 - 1  and  40 - 2  may be ultra-wideband antennas used for angle of arrival measurements. Antennas  40 - 1  and  40 - 2  may cover any desired frequencies (e.g., a 6.5 GHz frequency band, an 8 GHz frequency band, between 3.1 GHz and 10.6 GHz, and/or any other suitable frequencies). Antenna structures  40 ′ may convey radio-frequency signals in any desired frequencies (e.g., a 2.4 GHz band for WiFi® communications, a 5 GHz bands for WiFi® communications, a low communications band from 700 to 960 MHz, a low-midband from 960 to 1710 MHz, a midband from 1710 to 2170 MHz, a high band from 2300 to 2700 MHz, an ultra-high band from 3400 to 3700 MHz, GPS signals at 1575 MHz, or other suitable frequencies). Antenna structures  40 ′ may include, if desired, an antenna ground formed from ground structures  104  and an antenna resonating element formed from segment  108  of peripheral conductive structures  16 . 
     Antennas  40 - 1  and  40 - 2  may be ultra-wideband antennas used for angle of arrival measurements. Because antennas  40 - 1  and  40 - 2  are used for angle of arrival measurements, antennas  40 - 1  and  40 - 2  have the same shape (e.g., slots  62 - 1  and  62 - 2  have the same shape and dimensions). This may improve the accuracy of angle of arrivals determined by antennas  40 - 1  and  40 - 2 . As discussed in connection with  FIG. 6 , it may be desirable for the centers of antennas  40 - 1  and  40 - 2  to be separated by a specific distance d 1  (e.g., half of the effective wavelength of radio-frequency signals conveyed with antennas  40 - 1  and  40 - 2 ). In the example of  FIG. 8 , both slots  62 - 1  and  62 - 2  extend perpendicular to longitudinal axis  282 . Having slots  62 - 1  and  62 - 2  extend perpendicular to longitudinal axis  282  while maintaining a desired distance d 1  between slots  62 - 1  and  62 - 2  and ensuring structural integrity of antenna ground structures  104  and device  10  may be difficult. Therefore, other arrangements for antennas  40 - 1  and  40 - 2  may be used if desired. 
       FIG. 9  shows a similar arrangement to  FIG. 8 , with slot antennas  40 - 1  and  40 - 2  including slots  62 - 1  and  62 - 2  in ground structures  104 . However, in  FIG. 9 , both slots  62 - 1  and  62 - 2  extend parallel to longitudinal axis  282  (and the Y-axis). This may allow slots  62 - 1  and  62 - 2  to be separated by a desired distance d 1  without sacrificing structural integrity of ground structures  104 . Additionally, slots  62 - 1  and  62 - 2  in  FIG. 9  still have the same shape and dimensions, thus improving the accuracy of angle of arrivals determined by antennas  40 - 1  and  40 - 2 . 
     In the examples of  FIGS. 8 and 9 , the slots for antennas  40 - 1  and  40 - 2  are straight (e.g., slots  62 - 1  and  62 - 2  extend along a single length without any bends). These examples, however, are merely illustrative. To minimize the footprint of ground structures  104  occupied by antennas  40 - 1  and  40 - 2  (e.g., so that antennas  40 - 1  and  40 - 2  have as small an operating volume as possible to more closely resemble point sources for optimal angle of arrival estimation), slots  62 - 1  and  62 - 2  may have one or more bends as shown in  FIG. 10 . 
     As shown in  FIG. 10 , antennas  40 - 1  and  40 - 2  may each have a corresponding U-shaped slot  62 . Slots  62 - 1  and  62 - 2  may sometimes be referred to as slot elements or bent slot elements. Slot  62 - 1  of antenna  40 - 1  has a first slot portion  72  that extends parallel to longitudinal axis  282  (and the Y-axis), a second slot portion  74  that extends away from portion  72  perpendicular to longitudinal axis  282 , and a third slot portion  76  that extends away from portion  74  parallel to longitudinal axis  282  and portion  72 . The total length  68 - 1  of slot  62 - 1  (e.g., the summed length of slot portions  72 ,  74  and  76 ) may be selected to be approximately (e.g., within 15% of) half of the effective wavelength of the radio-frequency signals conveyed by antennas  40 - 1  and  40 - 2 . The effective wavelength of operation may take into account dielectric loading introduced by dielectric materials surrounding the antennas. In general, dielectric loading reduces the wavelength compared to free space. 
     Slot  62 - 2  of antenna  40 - 2  has a first slot portion  82  that extends parallel to longitudinal axis  282  (and the Y-axis), a second slot portion  84  that extends away from portion  82  perpendicular to longitudinal axis  282 , and a third slot portion  86  that extends away from portion  84  parallel to longitudinal axis  282  and portion  82 . The total length  68 - 2  of slot  62 - 2  (e.g., the summed length of slot portions  82 ,  84  and  86 ) may be selected to be approximately half of the effective wavelength of the radio-frequency signals conveyed with antennas  40 - 2  and  40 - 1 . Slot portion  84  of slot  62 - 2  may be aligned with slot portion  74  of slot  62 - 1  (e.g., slot portions  84  and  74  may share the same longitudinal axis). In the arrangement of  FIG. 10 , antenna feed  100 - 1  is coupled across first slot portion  72  of slot  62 - 1  and antenna feed  100 - 2  is coupled across first slot portion  82  of slot  62 - 2 . This example is merely illustrative. In another possible arrangement, antenna feed  100 - 1  may be coupled across first slot portion  72  of slot  62 - 1  and antenna feed  100 - 2  may be coupled across third slot portion  86  of slot  62 - 2 . Antenna feeds  100 - 1  and  100 - 2  may be coupled across any desired portion of respective slots  62 - 1  and  62 - 2 . 
     Distance d 1  between antennas  40 - 1  and  40 - 2  may have any desired length (e.g., between 15 and 30 millimeters, between 10 and 40 millimeters, between 20 and 30 millimeters, between 24 and 28 millimeters, greater than 10 millimeters, less than 50 millimeters, etc.). Slot portions  72 ,  74 , and  76  may have any desired lengths (e.g., about 5 millimeters, about 6 millimeters, between 4.5 and 5.5 millimeters, between 5.5 and 6.0 millimeters, between 5.0 and 6.0 millimeters, between 4 and 6 millimeters, between 3 and 10 millimeters, greater than 2 millimeters, less than 10 millimeters etc.). Antenna  40 - 2  may have the same shape and dimensions as antenna  40 - 1 . Therefore slot portion  82  of slot  62 - 2  may have the same length as slot portion  72  of slot  62 - 1 , slot portion  84  of slot  62 - 2  may have the same length as slot portion  74  of slot  62 - 1 , and slot portion  86  of slot  62 - 2  may have the same length as slot portion  76  of slot  62 - 1 . 
     The U-shaped slot  62 - 1  of antenna  40 - 1  may distribute currents on ground  104  such that the antenna currents around slot portion  72  cancel out with the antenna currents around slot portion  76 . This may, for example, limit the polarization of antenna  40 - 1  to a single phase (e.g., a linear polarization from slot portion  74 ). Similarly, the U-shaped slot  62 - 2  of antenna  40 - 2  may distribute currents on ground  104  such that the antenna currents around slot portion  82  cancel out with the antenna currents around slot portion  86 . This may, for example, limit the polarization of antenna  40 - 2  to a single phase (e.g., a linear polarization from slot portion  84 ). The U-shaped slots  62  of antennas  40 - 1  and  40 - 2  also reduce the effective volume of antennas  40 - 1  and  40 - 2  to the horizontal slot portions (e.g., portions  74  and  84 ), which allows antennas  40 - 1  and  40 - 2  to have as small an operating volume as possible to more closely resemble point sources for optimal angle of arrival estimation. 
     The examples of shapes for slots  62 - 1  and  62 - 2  in  FIGS. 8-10  are merely illustrative. In general, slots  62 - 1  and  62 - 2  may have any desired shapes (e.g., with no bends, one bend, two bends, more than two bends, etc.). Additionally, more than two slots may be included. One or both of antennas  40 - 1  and  40 - 2  may be formed from other structures within the electronic device. One or both of antennas  40 - 1  and  40 - 2  may also be used to convey radio-frequency signals at other frequencies (e.g., antenna  40 - 1  and/or antenna  40 - 2  may convey radio-frequency signals in a first band for measuring angle of arrival and may convey radio-frequency signals in a second band that are not used for measuring angle of arrival). Both antennas  40 - 1  and  40 - 2  may be oriented at any desired angle relative to longitudinal axis  282 . Both antennas  40 - 1  and  40 - 2  may include any desired number of curved and/or straight edges if desired. 
     The example of  FIG. 10  where two antennas are used for measuring angle of arrival is merely illustrative. With two antennas for determining angle of arrival (as in  FIG. 10 ), the angle of arrival within a single plane may be determined. For example, antennas  40 - 1  and  40 - 2  in  FIG. 10  may be used to determine azimuth angle θ. However, one or more additional antennas in antenna structures  40 ′ may be included to enable angle of arrival determination in multiple planes (e.g., azimuth angle θ and elevation angle φ may both be determined) and improve accuracy of the angle of arrival measurements. For example, in one illustrative example, antenna structures  40 ′ in  FIG. 10  include an additional antenna that is used for angle of arrival antenna measurements. The additional antenna may be positioned in a corner of electronic device  10  if desired. The additional antenna may be used for both angle of arrival measurements and other radio-frequency communication. In one suitable arrangement, antenna structures  40 ′ may include an additional antenna in the corner of the electronic device that is used for angle of arrival measurements and for radio-frequency communication in a wireless local area network (WLAN) band (e.g., a 2.4 GHz WiFi® band, a 5 GHz WiFi® band, and/or another desired wireless local area network band). 
       FIG. 11  is a cross-sectional side view of electronic device  10  as taken along line  92  in  FIG. 10 . As shown in  FIG. 11 , housing  12  ( FIG. 1 ) may include dielectric housing portions such as dielectric layer  324  and conductive housing portions such as conductive layer  320  (sometimes referred to herein as conductive housing wall  320 ). If desired, dielectric layer  324  may by formed under layer  320  such that layer  324  forms an exterior surface of device  10  (e.g., thereby protecting layer  320  from wear and/or hiding layer  320  from view of a user). Conductive housing portion  320  may form a portion of ground  104 . As examples, conductive housing portion  320  may be a conductive support plate or wall (e.g., a conductive back plate or rear housing wall) for device  10 . Conductive housing portion  320  may, if desired, extend across the width of device  10  (e.g., between two opposing sidewalls formed by peripheral housing structures  16 ). In one suitable arrangement, ground  104  includes both conductive portions of housing  12  (e.g., portions of a rear wall of housing  12  such as a conductive backplate  320  and portions of peripheral conductive housing structures  16  that are separated from segment  108  by peripheral gaps  18 ) as well as conductive portions of display  14  (e.g., conductive portions of display panel, a conductive plate that supports the display panel, and/or a conductive frame that supports the conductive plate and display panel). If desired, conductive housing portion  320  and the opposing sidewalls of device  10  may be formed from a single integral piece of metal or portion  320  may otherwise be shorted to the opposing sidewalls of device  10 . Dielectric layer  324  may be a thin glass, sapphire, ceramic, or sapphire layer or other dielectric coating, as examples. In another suitable arrangement, layer  324  may be omitted if desired. 
     As shown in  FIG. 11 , slots  62 - 1  and  62 - 2  may be formed in conductive housing layer  320 . A dielectric substrate  302  may be positioned adjacent to conductive housing layer  320  over slots  62 - 1  and  62 - 2 . Dielectric substrate  302  may provide mechanical support within electronic device  10  (e.g., for conductive housing layer  320 ). Dielectric substrate  302  may also support antenna structures for antenna  40 - 1  and/or antenna  40 - 2 . For example, dielectric substrate  302  may support transmission line structures for antenna  40 - 1 , transmission line structures for antenna  40 - 2 , structures for forming positive antenna feed terminal  96 - 1 , structures for forming positive antenna feed terminal  96 - 2 , structures for forming ground antenna feed terminal  98 - 1 , and/or structures for forming ground antenna feed terminal  98 - 2 . Dielectric substrate  302  may be formed from a polymer (e.g., polycarbonate-acrylonitrile butadiene styrene (PC-ABS) or any other desired material) and may sometimes be referred to as a plastic block. 
     To prevent components within electronic device  10  from being excited by radio-frequency signals conveyed using antennas  40 - 1  and  40 - 2 , a conductive shielding layer such as shielding layer  304  may cover dielectric substrate  302 . Without shielding layer  304 , antenna currents may be induced on adjacent conductive components in device  10 , which may serve to increase the effective volume of the antennas and limit the accuracy of the angle of arrival estimation. In addition, shielding layer  304  may prevent radio-frequency signals on the interior of electronic device  10  from interfering with radio-frequency signals conveyed using antennas  40 - 1  and  40 - 2 . Shielding layer  304  may be formed from any desired material (e.g., copper, aluminum, ferrite, or another desired conductive material). 
     The examples of  FIGS. 8-11  where antennas  40 - 1  and  40 - 2  are formed from slots in conductive housing layer  320  is merely illustrative. If desired, antennas  40 - 1  and  40 - 2  may instead be formed from antenna elements that are not slot-based. As shown in  FIG. 12 , antenna  40 - 1  may include a corresponding antenna resonating element  404 - 1  formed on substrate  402 - 1  and antenna  40 - 2  may include a corresponding antenna resonating element  404 - 2  formed on substrate  402 - 2 . Resonating elements  404 - 1  and  404 - 2  may, for example, be patch antenna resonating elements for antennas  40  (sometimes referred to herein as patch elements or conductive patches). Antenna resonating element  404 - 1  includes a first portion  412  that extends perpendicular to longitudinal axis  282  (and the Y-axis), a second portion  414  that extends away from first portion  412  parallel to longitudinal axis  282 , a third portion  416  that extends away from first portion  412  parallel to longitudinal axis  282 , and a fourth portion  418  that extends away from first portion  412  parallel to longitudinal axis  282 . The second and fourth portions  414  and  418  of antenna resonating element  404 - 1  may be longer than third portion  416 . The shape of antenna resonating element  404 - 1  (sometimes referred to as an “E-shape”) in  FIG. 12  is merely illustrative and antenna resonating element  404 - 1  may have any desired shape if desired. The E-shaped antenna resonating element may support radio-frequency communications in two or more frequency bands, as an example. 
     Antenna resonating element  404 - 2  includes a first portion  422  that extends perpendicular to longitudinal axis  282  (and the Y-axis), a second portion  424  that extends away from first portion  422  parallel to longitudinal axis  282 , a third portion  426  that extends away from first portion  422  parallel to longitudinal axis  282 , and a fourth portion  428  that extends away from first portion  412  parallel to longitudinal axis  282 . The second and fourth portions  424  and  428  of antenna resonating element  404 - 2  may be longer than third portion  426 . 
     Substrates  402 - 1  and  402 - 2  may be aligned with (e.g., formed within) openings in antenna ground  104 . Antenna resonating element  404 - 1  may be formed by conductive traces on substrate  402 - 1  and antenna resonating element  404 - 2  may be formed by conductive traces on substrate  402 - 2 . 
       FIG. 13  is a cross-sectional side view of electronic device  10  as taken along line  500  in  FIG. 12 . As shown, substrates  402 - 1  and  402 - 2  may be formed in openings in conductive housing layer  320 . Substrates  402 - 1  and  402 - 2  may support conductive traces for antenna resonating elements  404 - 1  and  404 - 1 . The substrates  402 - 1  and  402 - 2  may be formed from any desired material (e.g., ceramic, plastic, etc.). Shielding layer  304  may cover substrates  402 - 1  and  402 - 2 . 
     The examples of  FIGS. 8-13  where two antennas are used for angle of arrival determination are merely illustrative. With two antennas for determining angle of arrival (as in  FIGS. 8-13 ), the angle of arrival within a single plane may be determined. For example, antennas  40 - 1  and  40 - 2  in  FIGS. 8-13  may be used to determine azimuth angle θ. However, one or more additional antennas in the antenna structures of  FIGS. 8-13  may be included to enable angle of arrival determination in multiple planes (e.g., azimuth angle θ and elevation angle φ may both be determined) and improve accuracy of the angle of arrival measurements. In some arrangements, an antenna may be used for both angle of arrival measurements and other radio-frequency communication. 
     When arranged as shown in  FIGS. 8-13 , received signals of different polarizations are relatively uniform. For example, error in the detected angle of arrival with respect to incident polarization may be within a margin of error of 10° or less of the actual angle of arrival over all azimuthal and elevation angles. The effect of polarization on angle of arrival measurements may be minimal across a field-of-view of approximately 120° along azimuth angle θ and approximately 120° along elevation angle φ, as examples. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20170928
Publication Date: 20210126
Grant Date: 20210126
Priority Date: 20170928
Inventors: DI NALLO, CARLO
PASCOLINI, MATTIA
COOPER, AARON J.
TAYEBI, AMIN
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q13/16", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01S5/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q3/2605", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q3/2605", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/526", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q21/064", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/526", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01S3/46", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S3/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/064", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q21/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q3/267", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01S5/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/526", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q3/2605", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q21/30", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q3/267", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01S3/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/064", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S5/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01S3/46", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65809312