PATENT DOCUMENT

Publication Number: US-12206176-B2
Application Number: US-202117235240-A
Country: US
Kind Code: B2

Title: Electronic devices having bi-directional dielectric resonator antennas

Abstract:
An electronic device may have a first phased antenna array that radiates through a display and a second phased antenna array that radiates through a rear wall. The first array may include a front-facing dielectric resonator antenna and the second array may include a rear-facing dielectric resonator antenna. The front and rear-facing antennas may share a dielectric resonating element. Feed probe(s) may excite a first volume of the dielectric resonating element to radiate through the display and may excite a second volume of the dielectric resonating element to radiate through the rear wall. The dielectric resonating element may have a geometry that helps to isolate the front-facing dielectric resonator antenna from the rear-facing dielectric resonator antenna. The first and second arrays may collectively cover an entire sphere around the device while occupying a minimal amount of volume within the device.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a dielectric overmold; 
 a dielectric resonating element embedded in the dielectric overmold, wherein the dielectric resonating element has a longitudinal axis, a first surface at a first end of the longitudinal axis, a second surface at the second end of the longitudinal axis, and sidewalls extending orthogonally from the first surface to the second surface, and at least a portion of the sidewalls is covered by the dielectric overmold; 
 a first feed probe coupled to a first location on the sidewalls, wherein the first feed probe is configured to excite a first volume of the dielectric resonating element extending from the first location to the first end to radiate, through the first end, at frequencies greater than 10 GHZ, and at least a portion of the first feed probe is covered by the dielectric overmold; 
 a second feed probe coupled to a second location on the sidewalls that is interposed between the first location on the sidewalls and the second end of the dielectric resonating element, wherein the second feed probe is configured to excite a second volume of the dielectric resonating element extending from the second location to the second end to radiate, through the second end, at frequencies greater than 10 GHZ, and at least a portion of the second feed probe is covered by the dielectric overmold; and 
 a notch in the sidewalls between the first location on the sidewalls and the second location on the sidewalls. 
 
     
     
       2. The electronic device of  claim 1 , wherein the notch in the sidewalls is one of a plurality of notches in the sidewalls between the first location on the sidewalls and the second location on the sidewalls. 
     
     
       3. The electronic device of  claim 1 , wherein the notch in the sidewalls extends around all the sidewalls of the dielectric resonating element.

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 may be desirable to support wireless communications in millimeter wave and centimeter wave communications bands. Millimeter wave communications, which are sometimes referred to as extremely high frequency (EHF) communications, and centimeter wave communications involve communications at frequencies of about 10-300 GHz. 
     Operation at these frequencies can support high throughputs but may raise significant challenges. For example, radio-frequency signals at millimeter and centimeter wave frequencies are characterized by substantial attenuation and/or distortion during signal propagation through various mediums. In addition, if care is not taken, the antennas can be undesirably bulky and the presence of conductive electronic device components can make it difficult to incorporate circuitry for handling millimeter and centimeter wave communications into the electronic device. It can also be difficult to provide satisfactory wireless coverage at these frequencies within a full sphere around the electronic device. 
     It would therefore be desirable to be able to provide electronic devices with improved wireless communications circuitry such as communications circuitry that supports millimeter and centimeter wave communications. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry and a housing. The housing may have peripheral conductive housing structures and a rear wall. A display may be mounted to the peripheral conductive housing structures opposite the rear wall. A front-facing phased antenna array may radiate at frequencies greater than 10 GHz through the display. A rear-facing phased antenna array may radiate at frequencies greater than 10 GHz through the rear wall. 
     The front-facing phased antenna array may include a front-facing dielectric resonator antenna. The rear-facing phased antenna array may include a rear-facing dielectric resonator antenna. The front-facing and rear-facing dielectric resonator antennas may share a dielectric resonating element. The dielectric resonating element may include a dielectric column disposed within an opening in a printed circuit board. The dielectric column may be embedded within a dielectric overmold. The dielectric resonating element may be fed using at least a first feed probe for the front-facing dielectric resonator antenna and a second feed probe for the rear-facing dielectric resonator antenna. The antennas may also share a feed probe. The first feed probe may excite a volume of the dielectric column between the first feed probe and the display to radiate through the display. The second feed probe may excite a volume of the dielectric column between the second feed probe and the rear wall to radiate through the rear wall. 
     The dielectric column may have a geometry that helps to isolate the front-facing dielectric resonator antenna from the rear-facing dielectric resonator antenna. For example, the dielectric column may include a notch between the first feed probe and the second feed probe or the feed probes may be disposed within the notch. The feed probes may additionally or alternatively have inverted orientations. Additional feed probes may be used for covering additional polarizations. In this way, the device may include phased antenna arrays for covering an entire sphere around the device while occupying a minimal amount of volume within the device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an illustrative electronic device in accordance with some embodiments. 
         FIG.  2    is a schematic diagram of illustrative circuitry in an electronic device in accordance with some embodiments. 
         FIG.  3    is a schematic diagram of illustrative wireless circuitry in accordance with some embodiments. 
         FIG.  4    is a diagram of an illustrative phased antenna array in accordance with some embodiments. 
         FIG.  5    is a cross-sectional side view of an illustrative electronic device having phased antenna arrays for radiating through different sides of the device in accordance with some embodiments. 
         FIG.  6    is a cross-sectional side view of an illustrative electronic device having a bi-directional dielectric resonating element that is used in both a front-facing dielectric resonator antenna and a rear-facing dielectric resonator antenna in accordance with some embodiments. 
         FIG.  7    is a top view of an illustrative printed circuit having respective openings to accommodate each dielectric resonating element in a phased antenna array in accordance with some embodiments. 
         FIG.  8    is a top view of an illustrative printed circuit having a single opening that accommodates each dielectric resonating element in a phased antenna array in accordance with some embodiments. 
         FIG.  9    is a top view of an illustrative comb-shaped printed circuit for accommodating dielectric resonating elements in a phased antenna array in accordance with some embodiments. 
         FIG.  10    is a top view showing how an illustrative dielectric resonating element may be fed using a first feed probe for a front-facing dielectric resonator antenna and using a second feed probe for a rear-facing dielectric resonator antenna in accordance with some embodiments. 
         FIG.  11    is a top view showing how an illustrative dielectric resonating element may be fed using horizontally and vertically polarized feed probes for a front-facing dielectric resonator antenna and using horizontally and vertically polarized feed probe for a rear-facing dielectric resonator antenna in accordance with some embodiments. 
         FIG.  12    is a cross-sectional side view of an illustrative dielectric resonating element having a notch that accommodates a first feed probe for a front-facing dielectric resonator antenna and a second feed probe for a rear-facing dielectric resonator antenna in accordance with some embodiments. 
         FIG.  13    is a cross-sectional side view of an illustrative dielectric resonating element having a notch that helps to electromagnetically isolate a front-facing dielectric resonator antenna from a rear-facing dielectric resonator antenna in accordance with some embodiments. 
         FIG.  14    is a cross-sectional side view of front-facing and rear-facing dielectric resonator antennas formed from respective dielectric resonating elements mounted to opposing sides of an interposer in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG.  1    may be provided with wireless circuitry that includes antennas. The antennas may be used to transmit and/or receive wireless radio-frequency signals. The antennas may include phased antenna arrays that are used for performing wireless communications and/or spatial ranging operations using millimeter and centimeter wave signals. Millimeter wave signals, which are sometimes referred to as extremely high frequency (EHF) signals, propagate at frequencies above about 30 GHz (e.g., at 60 GHz or other frequencies between about 30 GHz and 300 GHz). Centimeter wave signals propagate at frequencies between about 10 GHz and 30 GHz. If desired, device  10  may also contain antennas for handling satellite navigation system signals, cellular telephone signals, local wireless area network signals, near-field communications, light-based wireless communications, or other wireless communications. 
     Device  10  may be a portable electronic device or other suitable electronic device. For example, 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, headset 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, a wireless access point, a wireless base station, an electronic device incorporated into a kiosk, building, or vehicle, 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 substantially planar housing wall such as rear housing wall  12 R (e.g., a planar housing wall). Rear housing wall  12 R may have slots that pass entirely through the rear housing wall and that therefore separate portions of housing  12  from each other. Rear housing wall  12 R may include conductive portions and/or dielectric portions. If desired, rear housing wall  12 R may include a planar metal layer covered by a thin layer or coating of dielectric such as glass, plastic, sapphire, or ceramic (e.g., a dielectric cover layer). Housing  12  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 materials. 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). 
     Housing  12  may include peripheral housing structures such as peripheral structures  12 W. Conductive portions of peripheral structures  12 W and conductive portions of rear housing wall  12 R may sometimes be referred to herein collectively as conductive structures of housing  12 . Peripheral structures  12 W 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, peripheral structures  12 W may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges and that extend from rear housing wall  12 R to the front face of device  10  (as an example). In other words, device  10  may have a length (e.g., measured parallel to the Y-axis), a width that is less than the length (e.g., measured parallel to the X-axis), and a height (e.g., measured parallel to the Z-axis) that is less than the width. Peripheral structures  12 W or part of peripheral structures  12 W 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 ) if desired. Peripheral structures  12 W may, if desired, form sidewall structures for device  10  (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.). 
     Peripheral structures  12 W 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, peripheral conductive sidewalls, peripheral conductive sidewall structures, conductive housing sidewalls, peripheral conductive housing sidewalls, sidewalls, sidewall structures, or a peripheral conductive housing member (as examples). Peripheral conductive housing structures  12 W may be formed from a metal such as stainless steel, aluminum, alloys, or other suitable materials. One, two, or more than two separate structures may be used in forming peripheral conductive housing structures  12 W. 
     It is not necessary for peripheral conductive housing structures  12 W to have a uniform cross-section. For example, the top portion of peripheral conductive housing structures  12 W may, if desired, have an inwardly protruding ledge that helps hold display  14  in place. The bottom portion of peripheral conductive housing structures  12 W may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). Peripheral conductive housing structures  12 W 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 conductive housing structures  12 W serve as a bezel for display  14 ), peripheral conductive housing structures  12 W may run around the lip of housing  12  (i.e., peripheral conductive housing structures  12 W may cover only the edge of housing  12  that surrounds display  14  and not the rest of the sidewalls of housing  12 ). 
     Rear housing wall  12 R may lie in a plane that is parallel to display  14 . In configurations for device  10  in which some or all of rear housing wall  12 R is formed from metal, it may be desirable to form parts of peripheral conductive housing structures  12 W as integral portions of the housing structures forming rear housing wall  12 R. For example, rear housing wall  12 R of device  10  may include a planar metal structure and portions of peripheral conductive housing structures  12 W on the sides of housing  12  may be formed as flat or curved vertically extending integral metal portions of the planar metal structure (e.g., housing structures  12 R and  12 W may be formed from a continuous piece of metal in a unibody configuration). 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 . Rear housing wall  12 R may have one or more, two or more, or three or more portions. Peripheral conductive housing structures  12 W and/or conductive portions of rear housing wall  12 R 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/cover 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 peripheral conductive housing structures  12 W and/or conductive portions of rear housing wall  12 R 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 . For example, active area AA may include an array of display pixels. The array of pixels may be formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels or other light-emitting diode pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. If desired, active area AA may include touch sensors such as touch sensor capacitive electrodes, force sensors, or other sensors for gathering a user input. 
     Display  14  may have an inactive border region that runs along one or more of the edges of active area AA. Inactive area IA of display  14  may be free of pixels for displaying images and may overlap circuitry and other internal device structures in housing  12 . To block these structures from view by a user of device  10 , the underside of the display cover layer or other layers in display  14  that overlap inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color. Inactive area IA may include a recessed region or notch that extends into active area AA (e.g., at speaker port  16 ). Active area AA may, for example, be defined by the lateral area of a display module for display  14  (e.g., a display module that includes pixel circuitry, touch sensor circuitry, etc.). 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, transparent ceramic, sapphire, or other transparent crystalline material, or other transparent layer(s). The display cover layer may have a planar shape, a convex curved profile, a shape with planar and curved portions, a layout that includes a planar main area surrounded on one or more edges with a portion that is bent out of the plane of the planar main area, or other suitable shapes. The display cover layer may cover the entire front face of device  10 . In another suitable arrangement, the display cover layer may cover substantially all of the front face of device  10  or only a portion of the front face of device  10 . Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button. An opening may also be formed in the display cover layer to accommodate ports such as speaker port  16  or a microphone port. Openings may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, etc.) and/or audio ports for audio components such as a speaker and/or a microphone if desired. 
     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 conductive support plate or backplate) that spans the walls of housing  12  (e.g., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of peripheral conductive housing structures  12 W). The conductive support plate may form an exterior rear surface of device  10  or may be covered by a dielectric cover layer such as a thin cosmetic layer, protective coating, 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 conductive support plate from view of the user (e.g., the conductive support plate may form part of rear housing wall  12 R). 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  12 W and opposing conductive ground structures such as conductive portions of rear housing wall  12 R, 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  22  and  20  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  22  and  20 . 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  22  and  20 ), thereby narrowing the slots in regions  22  and  20 . Region  22  may sometimes be referred to herein as lower region  22  or lower end  22  of device  10 . Region  20  may sometimes be referred to herein as upper region  20  or upper end  20  of device  10 . 
     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 lower region  22  and/or upper region  20  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 conductive housing structures  12 W may be provided with peripheral gap structures. For example, peripheral conductive housing structures  12 W may be provided with one or more dielectric-filled gaps such as gaps  18 , as shown in  FIG.  1   . The gaps in peripheral conductive housing structures  12 W may be filled with dielectric such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. Gaps  18  may divide peripheral conductive housing structures  12 W into one or more peripheral conductive segments. The conductive segments that are formed in this way may form parts of antennas in device  10  if desired. Other dielectric openings may be formed in peripheral conductive housing structures  12 W (e.g., dielectric openings other than gaps  18 ) and may serve as dielectric antenna windows for antennas mounted within the interior of device  10 . Antennas within device  10  may be aligned with the dielectric antenna windows for conveying radio-frequency signals through peripheral conductive housing structures  12 W. Antennas within device  10  may also be aligned with inactive area IA of display  14  for conveying radio-frequency signals through display  14 . 
     In order to provide an end user of device  10  with as large of a display as possible (e.g., to maximize an area of the device used for displaying media, running applications, etc.), it may be desirable to increase the amount of area at the front face of device  10  that is covered by active area AA of display  14 . Increasing the size of active area AA may reduce the size of inactive area IA within device  10 . This may reduce the area behind display  14  that is available for antennas within device  10 . For example, active area AA of display  14  may include conductive structures that serve to block radio-frequency signals handled by antennas mounted behind active area AA from radiating through the front face of device  10 . It would therefore be desirable to be able to provide antennas that occupy a small amount of space within device  10  (e.g., to allow for as large of a display active area AA as possible) while still allowing the antennas to communicate with wireless equipment external to device  10  with satisfactory efficiency bandwidth. 
     In a typical scenario, device  10  may have one or more upper antennas and one or more lower antennas. An upper antenna may, for example, be formed in upper region  20  of device  10 . A lower antenna may, for example, be formed in lower region  22  of device  10 . Additional antennas may be formed along the edges of housing  12  extending between regions  20  and  22  if desired. An example in which device  10  includes three or four upper antennas and five lower antennas is described herein as an example. 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. Other antennas for covering any other desired frequencies may also be mounted at any desired locations within the interior of device  10 . The example of  FIG.  1    is merely illustrative. If desired, housing  12  may have other shapes (e.g., a square shape, cylindrical shape, spherical shape, combinations of these and/or different shapes, etc.). 
     A schematic diagram of illustrative components that may be used in device  10  is shown in  FIG.  2   . As shown in  FIG.  2   , device  10  may include control circuitry  28 . Control circuitry  28  may include storage such as storage circuitry  30 . Storage circuitry  30  may include 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. 
     Control circuitry  28  may include processing circuitry such as processing circuitry  32 . Processing circuitry  32  may be used to control the operation of device  10 . Processing circuitry  32  may include on one or more microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application specific integrated circuits, central processing units (CPUs), etc. Control circuitry  28  may be configured to perform operations in device  10  using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing operations in device  10  may be stored on storage circuitry  30  (e.g., storage circuitry  30  may include non-transitory (tangible) computer readable storage media that stores the software code). The software code may sometimes be referred to as program instructions, software, data, instructions, or code. Software code stored on storage circuitry  30  may be executed by processing circuitry  32 . 
     Control 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, control circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using control 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 or other WPAN protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols, antenna-based spatial ranging protocols (e.g., radio detection and ranging (RADAR) protocols or other desired range detection protocols for signals conveyed at millimeter and centimeter wave frequencies), etc. Each communication protocol may be associated with a corresponding radio access technology (RAT) that specifies the physical connection methodology used in implementing the protocol. 
     Device  10  may include input-output circuitry  24 . Input-output circuitry  24  may include input-output devices  26 . Input-output devices  26  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  26  may include user interface devices, data port devices, sensors, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, gyroscopes, accelerometers or other components that can detect motion and device orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components. 
     Input-output circuitry  24  may include wireless circuitry such as wireless circuitry  34  for wirelessly conveying radio-frequency signals. While control circuitry  28  is shown separately from wireless circuitry  34  in the example of  FIG.  2    for the sake of clarity, wireless circuitry  34  may include processing circuitry that forms a part of processing circuitry  32  and/or storage circuitry that forms a part of storage circuitry  30  of control circuitry  28  (e.g., portions of control circuitry  28  may be implemented on wireless circuitry  34 ). As an example, control circuitry  28  may include baseband processor circuitry or other control components that form a part of wireless circuitry  34 . 
     Wireless circuitry  34  may include millimeter and centimeter wave transceiver circuitry such as millimeter/centimeter wave transceiver circuitry  38 . Millimeter/centimeter wave transceiver circuitry  38  may support communications at frequencies between about 10 GHz and 300 GHz. For example, millimeter/centimeter wave transceiver circuitry  38  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, millimeter/centimeter wave transceiver circuitry  38  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, millimeter/centimeter wave transceiver circuitry  38  may support IEEE 802.11ad communications at 60 GHz (e.g., WiGig or 60 GHz Wi-Fi bands around 57-61 GHz), and/or 5 th  generation mobile networks or 5 th  generation wireless systems (5G) New Radio (NR) Frequency Range 2 (FR2) communications bands between about 24 GHz and 90 GHz. Millimeter/centimeter wave transceiver circuitry  38  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.). 
     Millimeter/centimeter wave transceiver circuitry  38  (sometimes referred to herein simply as transceiver circuitry  38  or millimeter/centimeter wave circuitry  38 ) may perform spatial ranging operations using radio-frequency signals at millimeter and/or centimeter wave frequencies that are transmitted and received by millimeter/centimeter wave transceiver circuitry  38 . The received signals may be a version of the transmitted signals that have been reflected off of external objects and back towards device  10 . Control circuitry  28  may process the transmitted and received signals to detect or estimate a range between device  10  and one or more external objects in the surroundings of device  10  (e.g., objects external to device  10  such as the body of a user or other persons, other devices, animals, furniture, walls, or other objects or obstacles in the vicinity of device  10 ). If desired, control circuitry  28  may also process the transmitted and received signals to identify a two or three-dimensional spatial location of the external objects relative to device  10 . 
     Spatial ranging operations performed by millimeter/centimeter wave transceiver circuitry  38  are unidirectional. If desired, millimeter/centimeter wave transceiver circuitry  38  may also perform bidirectional communications with external wireless equipment such as external wireless equipment  10  (e.g., over a bi-directional millimeter/centimeter wave wireless communications link). The external wireless equipment may include other electronic devices such as electronic device  10 , a wireless base station, wireless access point, a wireless accessory, or any other desired equipment that transmits and receives millimeter/centimeter wave signals. Bidirectional communications involve both the transmission of wireless data by millimeter/centimeter wave transceiver circuitry  38  and the reception of wireless data that has been transmitted by external wireless equipment. The wireless data may, for example, include data that has been encoded into corresponding data packets such as wireless data associated with a telephone call, streaming media content, internet browsing, wireless data associated with software applications running on device  10 , email messages, etc. 
     If desired, wireless circuitry  34  may include transceiver circuitry for handling communications at frequencies below 10 GHz such as non-millimeter/centimeter wave transceiver circuitry  36 . For example, non-millimeter/centimeter wave transceiver circuitry  36  may handle wireless local area network (WLAN) frequency bands (e.g., Wi-Fi® (IEEE 802.11) or other WLAN communications bands) such as a 2.4 GHz WLAN band (e.g., from 2400 to 2480 MHz), a 5 GHz WLAN band (e.g., from 5180 to 5825 MHz), a Wi-Fi® 6E band (e.g., from 5925-7125 MHz), and/or other Wi-Fi® bands (e.g., from 1875-5160 MHz), wireless personal area network (WPAN) frequency bands such as the 2.4 GHz Bluetooth® band or other WPAN communications bands, cellular telephone frequency bands (e.g., bands from about 600 MHz to about 5 GHz, 3G bands, 4G LTE bands, 5G New Radio Frequency Range 1 (FR1) bands below 10 GHz, etc.), near-field communications frequency bands (e.g., at 13.56 MHz), satellite navigation frequency bands (e.g., a GPS band from 1565 to 1610 MHz, a Global Navigation Satellite System (GLONASS) band, a BeiDou Navigation Satellite System (BDS) band, etc.), ultra-wideband (UWB) frequency bands that operate under the IEEE 802.15.4 protocol and/or other ultra-wideband communications protocols, communications bands under the family of 3GPP wireless communications standards, communications bands under the IEEE 802.XX family of standards, and/or any other desired frequency bands of interest. The communications bands handled by the radio-frequency transceiver circuitry may sometimes be referred to herein as frequency bands or simply as “bands,” and may span corresponding ranges of frequencies. Non-millimeter/centimeter wave transceiver circuitry  36  and millimeter/centimeter wave transceiver circuitry  38  may each include one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive radio-frequency components, switching circuitry, transmission line structures, and other circuitry for handling radio-frequency signals. 
     In general, the transceiver circuitry in wireless circuitry  34  may cover (handle) any desired frequency bands of interest. As shown in  FIG.  2   , wireless circuitry  34  may include antennas  40 . The transceiver circuitry may convey radio-frequency signals using one or more antennas  40  (e.g., antennas  40  may convey the radio-frequency signals for the transceiver circuitry). The term “convey radio-frequency signals” as used herein means the transmission and/or reception of the radio-frequency signals (e.g., for performing unidirectional and/or bidirectional wireless communications with external wireless communications equipment). Antennas  40  may transmit the radio-frequency signals by radiating the radio-frequency signals into free space (or to freespace through intervening device structures such as a dielectric cover layer). Antennas  40  may additionally or alternatively receive the radio-frequency signals from free space (e.g., through intervening devices structures such as a dielectric cover layer). The transmission and reception of radio-frequency signals by antennas  40  each involve the excitation or resonance of antenna currents on an antenna resonating element in the antenna by the radio-frequency signals within the frequency band(s) of operation of the antenna. 
     In satellite navigation system links, cellular telephone links, and other long-range links, radio-frequency signals are typically used to convey data over thousands of feet or miles. In Wi-Fi® and Bluetooth® links at 2.4 and 5 GHz and other short-range wireless links, radio-frequency signals are typically used to convey data over tens or hundreds of feet. Millimeter/centimeter wave transceiver circuitry  38  may convey radio-frequency signals over short distances that travel over a line-of-sight path. To enhance signal reception for millimeter and centimeter wave communications, phased antenna arrays and beam forming (steering) techniques may be used (e.g., schemes in which antenna signal phase and/or magnitude for each antenna in an array are adjusted to perform beam steering). Antenna diversity schemes may also be used to ensure that the antennas that have become blocked or that are otherwise degraded due to the operating environment of device  10  can be switched out of use and higher-performing antennas used in their place. 
     Antennas  40  in wireless 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, monopole antenna structures, dipole antenna structures, helical antenna structures, Yagi (Yagi-Uda) antenna structures, hybrids of these designs, etc. In another suitable arrangement, antennas  40  may include antennas with dielectric resonating elements such as dielectric resonator antennas. 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 non-millimeter/centimeter wave wireless link for non-millimeter/centimeter wave transceiver circuitry  36  and another type of antenna may be used in conveying radio-frequency signals at millimeter and/or centimeter wave frequencies for millimeter/centimeter wave transceiver circuitry  38 . Antennas  40  that are used to convey radio-frequency signals at millimeter and centimeter wave frequencies may be arranged in one or more phased antenna arrays. 
     A schematic diagram of an antenna  40  that may be formed in a phased antenna array for conveying radio-frequency signals at millimeter and centimeter wave frequencies is shown in  FIG.  3   . As shown in  FIG.  3   , antenna  40  may be coupled to millimeter/centimeter (MM/CM) wave transceiver circuitry  38 . Millimeter/centimeter wave transceiver circuitry  38  may be coupled to antenna feed  44  of antenna  40  using a transmission line path that includes radio-frequency transmission line  42 . Radio-frequency transmission line  42  may include a positive signal conductor such as signal conductor  46  and may include a ground conductor such as ground conductor  48 . Ground conductor  48  may be coupled to the antenna ground for antenna  40  (e.g., over a ground antenna feed terminal of antenna feed  44  located at the antenna ground). Signal conductor  46  may be coupled to the antenna resonating element for antenna  40 . For example, signal conductor  46  may be coupled to a positive antenna feed terminal of antenna feed  44  located at the antenna resonating element. 
     In another suitable arrangement, antenna  40  may be a probe-fed antenna that is fed using a feed probe. In this arrangement, antenna feed  44  may be implemented as a feed probe. Signal conductor  46  may be coupled to the feed probe. Radio-frequency transmission line  42  may convey radio-frequency signals to and from the feed probe. When radio-frequency signals are being transmitted over the feed probe and the antenna, the feed probe may excite the resonating element for the antenna (e.g., may excite electromagnetic resonant modes of a dielectric antenna resonating element for antenna  40 ). The resonating element may radiate the radio-frequency signals in response to excitation by the feed probe. Similarly, when radio-frequency signals are received by the antenna (e.g., from free space), the radio-frequency signals may excite the resonating element for the antenna (e.g., may excite electromagnetic resonant modes of the dielectric antenna resonating element for antenna  40 ). This may produce antenna currents on the feed probe and the corresponding radio-frequency signals may be passed to the transceiver circuitry over the radio-frequency transmission line. 
     Radio-frequency transmission line  42  may include a stripline transmission line (sometimes referred to herein simply as a stripline), a coaxial cable, a coaxial probe realized by metalized vias, a microstrip transmission line, an edge-coupled microstrip transmission line, an edge-coupled stripline transmission lines, a waveguide structure, combinations of these, etc. Multiple types of transmission lines may be used to form the transmission line path that couples millimeter/centimeter wave transceiver circuitry  38  to antenna feed  44 . Filter circuitry, switching circuitry, impedance matching circuitry, phase shifter circuitry, amplifier circuitry, and/or other circuitry may be interposed on radio-frequency transmission line  42 , if desired. 
     Radio-frequency transmission lines in device  10  may be integrated into ceramic substrates, rigid printed circuit boards, and/or flexible printed circuits. In one suitable arrangement, radio-frequency transmission lines in device  10  may be 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). 
       FIG.  4    shows how antennas  40  for handling radio-frequency signals at millimeter and centimeter wave frequencies may be formed in a phased antenna array. As shown in  FIG.  4   , phased antenna array  54  (sometimes referred to herein as array  54 , antenna array  54 , or array  54  of antennas  40 ) may be coupled to radio-frequency transmission lines  42 . For example, a first antenna  40 - 1  in phased antenna array  54  may be coupled to a first radio-frequency transmission line  42 - 1 , a second antenna  40 - 2  in phased antenna array  54  may be coupled to a second radio-frequency transmission line  42 - 2 , an Nth antenna  40 -N in phased antenna array  54  may be coupled to an Nth radio-frequency transmission line  42 -N, etc. While antennas  40  are described herein as forming a phased antenna array, the antennas  40  in phased antenna array  54  may sometimes also be referred to as collectively forming a single phased array antenna. 
     Antennas  40  in phased antenna array  54  may be arranged in any desired number of rows and columns or in any other desired pattern (e.g., the antennas need not be arranged in a grid pattern having rows and columns). During signal transmission operations, radio-frequency transmission lines  42  may be used to supply signals (e.g., radio-frequency signals such as millimeter wave and/or centimeter wave signals) from millimeter/centimeter wave transceiver circuitry  38  ( FIG.  3   ) to phased antenna array  54  for wireless transmission. During signal reception operations, radio-frequency transmission lines  42  may be used to supply signals received at phased antenna array  54  (e.g., from external wireless equipment or transmitted signals that have been reflected off of external objects) to millimeter/centimeter wave transceiver circuitry  38  ( FIG.  3   ). 
     The use of multiple antennas  40  in phased antenna array  54  allows beam steering arrangements to be implemented by controlling the relative phases and magnitudes (amplitudes) of the radio-frequency signals conveyed by the antennas. In the example of  FIG.  4   , antennas  40  each have a corresponding radio-frequency phase and magnitude controller  50  (e.g., a first phase and magnitude controller  50 - 1  interposed on radio-frequency transmission line  42 - 1  may control phase and magnitude for radio-frequency signals handled by antenna  40 - 1 , a second phase and magnitude controller  50 - 2  interposed on radio-frequency transmission line  42 - 2  may control phase and magnitude for radio-frequency signals handled by antenna  40 - 2 , an Nth phase and magnitude controller  50 -N interposed on radio-frequency transmission line  42 -N may control phase and magnitude for radio-frequency signals handled by antenna  40 -N, etc.). 
     Phase and magnitude controllers  50  may each include circuitry for adjusting the phase of the radio-frequency signals on radio-frequency transmission lines  42  (e.g., phase shifter circuits) and/or circuitry for adjusting the magnitude of the radio-frequency signals on radio-frequency transmission lines  42  (e.g., power amplifier and/or low noise amplifier circuits). Phase and magnitude controllers  50  may sometimes be referred to collectively herein as beam steering circuitry (e.g., beam steering circuitry that steers the beam of radio-frequency signals transmitted and/or received by phased antenna array  54 ). 
     Phase and magnitude controllers  50  may adjust the relative phases and/or magnitudes of the transmitted signals that are provided to each of the antennas in phased antenna array  54  and may adjust the relative phases and/or magnitudes of the received signals that are received by phased antenna array  54 . Phase and magnitude controllers  50  may, if desired, include phase detection circuitry for detecting the phases of the received signals that are received by phased antenna array  54 . The term “beam” or “signal beam” may be used herein to collectively refer to wireless signals that are transmitted and received by phased antenna array  54  in a particular direction. The signal beam may exhibit a peak gain that is oriented in a particular pointing direction at a corresponding pointing angle (e.g., based on constructive and destructive interference from the combination of signals from each antenna in the phased antenna array). The term “transmit beam” may sometimes be used herein to refer to radio-frequency signals that are transmitted in a particular direction whereas the term “receive beam” may sometimes be used herein to refer to radio-frequency signals that are received from a particular direction. 
     If, for example, phase and magnitude controllers  50  are adjusted to produce a first set of phases and/or magnitudes for transmitted radio-frequency signals, the transmitted signals will form a transmit beam as shown by beam B 1  of  FIG.  4    that is oriented in the direction of point A. If, however, phase and magnitude controllers  50  are adjusted to produce a second set of phases and/or magnitudes for the transmitted signals, the transmitted signals will form a transmit beam as shown by beam B 2  that is oriented in the direction of point B. Similarly, if phase and magnitude controllers  50  are adjusted to produce the first set of phases and/or magnitudes, radio-frequency signals (e.g., radio-frequency signals in a receive beam) may be received from the direction of point A, as shown by beam B 1 . If phase and magnitude controllers  50  are adjusted to produce the second set of phases and/or magnitudes, radio-frequency signals may be received from the direction of point B, as shown by beam B 2 . 
     Each phase and magnitude controller  50  may be controlled to produce a desired phase and/or magnitude based on a corresponding control signal  52  received from control circuitry  28  of  FIG.  2    (e.g., the phase and/or magnitude provided by phase and magnitude controller  50 - 1  may be controlled using control signal  52 - 1 , the phase and/or magnitude provided by phase and magnitude controller  50 - 2  may be controlled using control signal  52 - 2 , etc.). If desired, the control circuitry may actively adjust control signals  52  in real time to steer the transmit or receive beam in different desired directions over time. Phase and magnitude controllers  50  may provide information identifying the phase of received signals to control circuitry  28  if desired. 
     When performing wireless communications using radio-frequency signals at millimeter and centimeter wave frequencies, the radio-frequency signals are conveyed over a line of sight path between phased antenna array  54  and external communications equipment. If the external object is located at point A of  FIG.  4   , phase and magnitude controllers  50  may be adjusted to steer the signal beam towards point A (e.g., to steer the pointing direction of the signal beam towards point A). Phased antenna array  54  may transmit and receive radio-frequency signals in the direction of point A. Similarly, if the external communications equipment is located at point B, phase and magnitude controllers  50  may be adjusted to steer the signal beam towards point B (e.g., to steer the pointing direction of the signal beam towards point B). Phased antenna array  54  may transmit and receive radio-frequency signals in the direction of point B. In the example of  FIG.  4   , beam steering is shown as being performed over a single degree of freedom for the sake of simplicity (e.g., towards the left and right on the page of  FIG.  4   ). However, in practice, the beam may be steered over two or more degrees of freedom (e.g., in three dimensions, into and out of the page and to the left and right on the page of  FIG.  4   ). Phased antenna array  54  may have a corresponding field of view over which beam steering can be performed (e.g., in a hemisphere or a segment of a hemisphere over the phased antenna array). If desired, device  10  may include multiple phased antenna arrays that each face a different direction to provide coverage from multiple sides of the device. 
       FIG.  5    is a cross-sectional side view of device  10  in an example where device  10  has multiple phased antenna arrays. As shown in  FIG.  5   , peripheral conductive housing structures  12 W may extend around the (lateral) periphery of device  10  and may extend from rear housing wall  12 R to display  14 . Display  14  may have a display module such as display module  68  (sometimes referred to as a display panel). Display module  68  may include pixel circuitry, touch sensor circuitry, force sensor circuitry, and/or any other desired circuitry for forming active area AA of display  14 . Display  14  may include a dielectric cover layer such as display cover layer  56  that overlaps display module  68 . Display module  68  may emit image light and may receive sensor input through display cover layer  56 . Display cover layer  56  and display  14  may be mounted to peripheral conductive housing structures  12 W. The lateral area of display  14  that does not overlap display module  68  may form inactive area IA of display  14 . 
     Device  10  may include multiple phased antenna arrays  54  such as a rear-facing phased antenna array  54 - 1 . As shown in  FIG.  5   , phased antenna array  54 - 1  may transmit and receive radio-frequency signals  60  at millimeter and centimeter wave frequencies through rear housing wall  12 R. In scenarios where rear housing wall  12 R includes metal portions, radio-frequency signals  60  may be conveyed through an aperture or opening in the metal portions of rear housing wall  12 R or may be conveyed through other dielectric portions of rear housing wall  12 R. The aperture may be overlapped by a dielectric cover layer or dielectric coating that extends across the lateral area of rear housing wall  12 R (e.g., between peripheral conductive housing structures  12 W). Phased antenna array  54 - 1  may perform beam steering for radio-frequency signals  60  across the hemisphere below device  10 , as shown by arrow  62 . 
     Phased antenna array  54 - 1  may be mounted to a substrate such as substrate  64 . Substrate  64  may be an integrated circuit chip, a flexible printed circuit, a rigid printed circuit board, or other substrate. Substrate  64  may sometimes be referred to herein as antenna module  64 . If desired, transceiver circuitry (e.g., millimeter/centimeter wave transceiver circuitry  38  of  FIG.  2   ) may be mounted to antenna module  64 . Phased antenna array  54 - 1  may be adhered to rear housing wall  12 R using adhesive, may be pressed against (e.g., in contact with) rear housing wall  12 R, or may be spaced apart from rear housing wall  12 R. 
     The field of view of phased antenna array  54 - 1  is limited to the hemisphere under the rear face of device  10 . Display module  68  and other components  58  (e.g., portions of input-output circuitry  24  or control circuitry  28  of  FIG.  2   , a battery for device  10 , etc.) in device  10  include conductive structures. If care is not taken, these conductive structures may block radio-frequency signals from being conveyed by a phased antenna array within device  10  across the hemisphere over the front face of device  10 . While an additional phased antenna array for covering the hemisphere over the front face of device  10  may be mounted against display cover layer  56  within inactive area IA, there may be insufficient space between the lateral periphery of display module  68  and peripheral conductive housing structures  12 W to form all of the circuitry and radio-frequency transmission lines necessary to fully support the phased antenna array. 
     In order to mitigate these issues and provide coverage through the front face of device  10 , a front-facing phased antenna array may be mounted within peripheral region  66  of device  10 . The antennas in the front-facing phased antenna array may include dielectric resonator antennas. Dielectric resonator antennas may occupy less area in the X-Y plane of  FIG.  5    than other types of antennas such as patch antennas and slot antennas. Implementing the antennas as dielectric resonator antennas may allow the radiating elements of the front-facing phased antenna array to fit within inactive area IA between display module  68  and peripheral conductive housing structures  12 W. At the same time, the radio-frequency transmission lines and other components for the phased antenna array may be located behind (under) display module  68 . While examples are described herein in which the phased antenna array is a front-facing phased antenna array that radiates through display  14 , in another suitable arrangement, the phased antenna array may be a side-facing phased antenna array that radiates through one or more apertures in peripheral conductive housing structures  12 W. 
     In order to further optimize space within device  10  while providing a full sphere of wireless coverage around device  10 , the dielectric resonator antennas in peripheral region  66  may include front-facing dielectric resonator antennas (e.g., in a front-facing phased antenna array of dielectric resonator antennas) and rear-facing dielectric resonator antennas (e.g., in a rear-facing phased antenna array of dielectric resonator antennas). The front-facing dielectric resonator antennas may convey radio-frequency signals through display cover layer  56  and within the hemisphere over the front face of device  10  (display  14 ). The rear-facing dielectric resonator antennas may convey radio-frequency signals through dielectric portions of rear housing wall  12 R and within the hemisphere under the rear face of device  10  (rear housing wall  12 R). In these examples, device  10  may also include phased antenna array  54 - 1  for providing additional coverage within the hemisphere under the rear face of device  10  or phased antenna array  54 - 1  may be omitted, thereby saving additional space within device  10 . In order to allow for front-facing and rear-facing dielectric resonator antennas to fit within peripheral region  66  (e.g., without requiring device  10  to be excessively thick in the Z-dimension), the front-facing dielectric resonator antennas and the rear-facing dielectric resonator antennas may share dielectric resonating elements. 
       FIG.  6    is a cross-sectional side view showing how a given dielectric resonating element in peripheral region  66  of device  10  may be used to form both a front-facing dielectric resonator antenna and a rear-facing dielectric resonator antenna. As shown in  FIG.  6   , device  10  may include a front-facing phased antenna array having a given front-facing antenna  40 F and may include a rear-facing phased antenna array having a given rear-facing antenna  40 R (e.g., mounted within peripheral region  66  of  FIG.  5   ). The front-facing phased antenna array may include any desired number of front-facing antennas (e.g., a one-dimensional or two-dimensional array of front-facing antennas). The rear-facing phased antenna array may include any desired number of rear-facing antennas (e.g., a one-dimensional or two-dimensional array of rear-facing antennas). 
     Antennas  40 F and  40 R may each be dielectric resonator antennas that share a single dielectric resonating element  92 . Dielectric resonating element  92  may be mounted to a substrate such as printed circuit  74 . Printed circuit  74  may be a rigid printed circuit board or a flexible printed circuit, as examples. Printed circuit  74  has a lateral area (e.g., in the X-Y plane of  FIG.  6   ) that extends along rear housing wall  12 R. Printed circuit  74  may be secured to rear housing wall  12 R and/or peripheral conductive housing structures  12 W using one or more screws (e.g., grounding screws), adhesive, and/or any other desired structures. The millimeter/centimeter wave transceiver circuitry for front-facing antenna  40 F and rear-facing antenna  40 R may be mounted to printed circuit  74  or to a different substrate in device  10  (e.g., a main logic board or other substrate separate from printed circuit  74 ). 
     Printed circuit  74  may include multiple stacked dielectric layers. The dielectric layers may include polyimide, ceramic, liquid crystal polymer, plastic, and/or any other desired dielectric materials. Conductive traces may be patterned onto the top surface of printed circuit  74 , the bottom surface of printed circuit  74 , and/or on the dielectric layers within printed circuit  74 . Some of the conductive traces may be held at a ground potential to form ground traces (e.g., part of the antenna ground) for front-facing antenna  40 F and rear-facing antenna  40 R. The ground traces may be coupled to a system ground in device  10  (e.g., using solder, welds, conductive adhesive, conductive tape, conductive brackets, conductive pins, conductive screws, conductive clips, combinations of these, etc.). For example, the ground traces may be coupled to peripheral conductive housing structures  12 W, conductive portions of rear housing wall  12 R, or other grounded structures in device  10 . 
     Printed circuit  74  may include one or more openings such as opening  76 . Dielectric resonating element  92  may be mounted within opening  76  (e.g., dielectric resonating element  92  may protrude through opening  76 ). Front-facing antenna  40 F may be fed using one or more radio-frequency transmission lines formed on and/or embedded within printed circuit  74 . Rear-facing antenna  40 R may also be fed using one or more radio-frequency transmission lines formed on and/or embedded within printed circuit  74 . The radio-frequency transmission lines have ground conductors (e.g., ground conductor  48  of  FIG.  3   ) that include the ground traces on printed circuit  74 . The radio-frequency transmission lines may also have signal conductors (e.g., signal conductor  46  of  FIG.  3   ) that include some of the conductive traces on printed circuit  74 . 
     Dielectric resonating element  92  may be formed from a column (pillar) of dielectric material mounted within opening  76  in printed circuit  74 . Dielectric resonating element  92  may be embedded within (e.g., laterally surrounded by) a dielectric substrate such as dielectric overmold  86 . While a non-zero clearance is shown between dielectric overmold  86  and circuit board  74  in  FIG.  6    for the sake of clarity, dielectric overmold  86  may completely fill opening  76  if desired. Dielectric overmold  86  may help to secure dielectric resonating element  92  to printed circuit  74 . If desired, dielectric overmold  86  may help to secure dielectric resonating element  92  to peripheral conductive housing structures  12 W. 
     Dielectric resonating element  92  may have a first (bottom) surface  82  facing rear housing wall  12 R. Rear housing wall  12 R may include conductive material. A slot such as slot  70  may be formed in the conductive material of rear housing wall  12 R at a location overlapping dielectric resonating element  92 . A dielectric antenna window such as dielectric antenna window  72  may be mounted to rear housing wall  12 R and may cover slot  70 . Additionally or alternatively, a dielectric cover layer may cover the entire rear surface of device  10  (rear housing wall  12 R). Slot  70  may sometimes also be referred to herein as opening  70  or antenna window  70 . 
     Dielectric resonating element  92  may have a second (top) surface  84  at display  14 . Top surface  84  may be laterally interposed between display module  68  and peripheral conductive housing structures  12 W (e.g., part of dielectric resonating element  92  may be located within gap  96  between display module  68  and peripheral conductive housing structures  12 W, which forms part of the inactive area of display  14 ). Dielectric resonating element  92  may have vertical sidewalls  94  that extend from top surface  84  to bottom surface  82 . Dielectric resonating element  92  may have a longitudinal axis  98  (e.g., parallel to the Z-axis) that runs through the center of both top surface  84  and bottom surface  82 . Longitudinal axis  98  may be, for example, the longest rectangular dimension of dielectric resonating element  92 . Dielectric resonating element  92  may have a height (measured parallel to longitudinal axis  98 ) measured from top surface  84  to bottom surface  82 . Dielectric resonating element  92  may also have a length (measured parallel to the X-axis) and a width (measured parallel to the Y-axis) that are each less than the height of dielectric resonating element  92 . 
     Dielectric resonating element  92  may have a central axis  100  that passes through longitudinal axis  98  and that divides (e.g., bisects) the height of dielectric resonating element  92 . Central axis  100  is oriented orthogonal to longitudinal axis  98 . Central axis  100  need not bisect the height of dielectric resonating element  92 . Central axis  100  may separate the portion of dielectric resonating element  92  used to form front-facing antenna  40 F from the portion of dielectric resonating element  92  used to form rear-facing antenna  40 R. The operating (resonant) frequency of front-facing antenna  40 F may be selected by adjusting the dimensions of dielectric resonating element  92  above central axis  100 . Similarly, the operating (resonant) frequency of rear-facing antenna  40 R may be selected by adjusting the dimensions of dielectric resonating element  92  below central axis  100 . The geometry of dielectric resonating element  92  below central axis  100  may also have some effect on the operating frequency of front-facing antenna  40 F and/or the geometry of dielectric resonating element  92  above central axis  100  may also have some effect on the operating frequency of rear-facing antenna  40 R. 
     Dielectric resonating element  92  may be formed from a column of dielectric material having a first dielectric constant ε r1 . Dielectric constant ε r1  may be relatively high (e.g., greater than 10.0, greater than 12.0, greater than 15.0, greater than 20.0, between 15.0 and 40.0, between 10.0 and 50.0, between 18.0 and 30.0, between 12.0 and 45.0, etc.). In one suitable arrangement, dielectric resonating element  92  may be formed from zirconia or a ceramic material. Other dielectric materials may be used to form dielectric resonating element  92  if desired. 
     Dielectric overmold  86  may be formed from a material having dielectric constant ε r2 . Dielectric constant ε r2  may be less than dielectric constant ε r1  of dielectric resonating element  92  (e.g., less than 18.0, less than 15.0, less than 10.0, between 3.0 and 4.0, less than 5.0, between 2.0 and 5.0, etc.). Dielectric constant ε r2  may be less than dielectric constant ε r1  by at least 10.0, 5.0, 15.0, 12.0, 6.0, etc. In one suitable arrangement, dielectric overmold  86  may be formed from molded plastic (e.g., injection-molded plastic). Other dielectric materials may be used to form dielectric overmold  86  or dielectric overmold  86  may be omitted if desired. The difference in dielectric constant between dielectric resonating element  92  and dielectric overmold  86  may help to establish a radio-frequency boundary condition between dielectric resonating element  92  and dielectric overmold  86  from bottom surface  82  to top surface  84 . This may configure dielectric resonating element  92  to serve as a waveguide for propagating radio-frequency signals at millimeter and centimeter wave frequencies. 
     Dielectric resonating element  92  may radiate radio-frequency signals when excited by the signal conductor(s) for the radio-frequency transmission line(s) in printed circuit  74 . The antennas formed from dielectric resonating element  92  may be fed using radio-frequency feed probes such as feed probes  78 . Feed probes  78  may form part of the antenna feeds for front-facing antenna  40 F and rear-facing antenna  40 R (e.g., antenna feed  44  of  FIG.  3   ). Front-facing antenna  40 F may be fed using at least one of the feed probes  78 . Rear-facing antenna  40 R may also be fed using at least one of the feed probes  78 . If desired, antennas  40 F and  40 R may be fed using different (independent) feed probes  78 . 
     As shown in  FIG.  6   , each feed probe  78  may include a respective feed conductor  102 . At least a portion of feed conductor  102  (e.g., a patch-shaped portion of feed conductor  102 ) may be in contact with a sidewall  94  of dielectric resonating element  92 . Feed conductor  102  may be formed from stamped sheet metal that is folded and pressed against sidewall  94  (e.g., by biasing structures and/or by dielectric overmold  86 ). In another implementation, feed conductor  102  may be formed from conductive traces that are patterned directly onto sidewall  94  (e.g., using a sputtering process, a laser direct structuring process, or other conductive deposition techniques). A portion of feed conductor  102  may be coupled to signal traces on printed circuit  74  using conductive interconnect structures  80 . Conductive interconnect structures  80  may include solder, welds, conductive adhesive, conductive tape, conductive foam, conductive springs, conductive brackets, and/or any other desired conductive interconnect structures. 
     The signal traces in printed circuit  74  may convey radio-frequency signals to and from feed probes  78 . Feed probes  78  may electromagnetically couple the radio-frequency signals on the signal traces into dielectric resonating element  92 . The feed probe  78  for front-facing antenna  40 F may couple radio-frequency signals into dielectric resonating element  92  that excite one or more electromagnetic modes of dielectric resonating element  92  located predominantly between central axis  100  and top surface  84  (e.g., radio-frequency cavity or waveguide modes between around central axis  100  and top surface  84 ). When excited by the feed probe  78  for front-facing antenna  40 F, these electromagnetic modes of dielectric resonating element  92  may configure the dielectric resonating element to serve as a waveguide that propagates the wavefronts of radio-frequency signals  88  along the length of dielectric resonating element  92  (e.g., in the direction of the Z-axis of  FIG.  6   ), through top surface  84 , and through display  14 . 
     For example, during signal transmission, the feed probe  78  for front-facing antenna  40 F may couple the radio-frequency signals on the signal traces into dielectric resonating element  92 . This may serve to excite one or more electromagnetic modes of the volume of dielectric resonating element  92  between around central axis  100  and top surface  84 , resulting in the propagation of radio-frequency signals  88  up the length of dielectric resonating element  92  and to the exterior of device  10  through display cover layer  56 . Similarly, during signal reception, radio-frequency signals  88  may be received through display cover layer  56 . The received radio-frequency signals may excite the electromagnetic modes of dielectric resonating element  92  between top surface  84  and around central axis  100 , resulting in the propagation of the radio-frequency signals down the length of dielectric resonating element  92 . The feed probe  78  for front-facing antenna  40 F may couple the received radio-frequency signals onto a corresponding radio-frequency transmission line on printed circuit  74 , which passes the radio-frequency signals to the millimeter/centimeter wave transceiver circuitry in device  10 . 
     Similarly, the feed probe  78  for rear-facing antenna  40 R may couple radio-frequency signals into dielectric resonating element  92  that excite one or more electromagnetic modes of dielectric resonating element  92  located predominantly between central axis  100  and bottom surface  82  (e.g., radio-frequency cavity or waveguide modes between around central axis  100  and bottom surface  82 ). When excited by the feed probe  78  for rear-facing antenna  40 R, these electromagnetic modes of dielectric resonating element  92  may configure the dielectric resonating element to serve as a waveguide that propagates the wavefronts of radio-frequency signals  90  along the length of dielectric resonating element  92  (e.g., in the direction of the Z-axis of  FIG.  6   ), through bottom surface  82 , and through dielectric antenna window  72 . 
     For example, during signal transmission, the feed probe  78  for rear-facing antenna  40 R may couple the radio-frequency signals on the signal traces into dielectric resonating element  92 . This may serve to excite one or more electromagnetic modes of the volume of dielectric resonating element  92  between around central axis  100  and bottom surface  82 , resulting in the propagation of radio-frequency signals  90  down the length of dielectric resonating element  92  and to the exterior of device  10  through dielectric antenna window  72  and slot  70 . Similarly, during signal reception, radio-frequency signals  90  may be received through antenna window  72  and slot  70 . The received radio-frequency signals may excite the electromagnetic modes of dielectric resonating element  92  between bottom surface  82  and around central axis  100 , resulting in the propagation of the radio-frequency signals up the length of dielectric resonating element  92 . The feed probe  78  for rear-facing antenna  40 R may couple the received radio-frequency signals onto a corresponding radio-frequency transmission line on printed circuit  74 , which passes the radio-frequency signals to the millimeter/centimeter wave transceiver circuitry in device  10 . The relatively large difference in dielectric constant between dielectric resonating element  92  and dielectric overmold  86  may allow dielectric resonating element  92  to convey radio-frequency signals  88  and  90  with a relatively high antenna efficiency (e.g., by establishing a strong boundary between dielectric resonating element  92  and dielectric overmold  86  for the radio-frequency signals). The relatively high dielectric constant of dielectric resonating element  92  may also allow the dielectric resonating element  92  to occupy a relatively small volume compared to scenarios where materials with a lower dielectric constant are used. 
     The dimensions of feed probes  78  may be selected to help match the impedance of the radio-frequency transmission lines in printed circuit  74  to the impedance of dielectric resonating element  92 . Each feed probe  78  may be located on a respective sidewall  94  of dielectric resonating element  92  to provide antennas  40 F and  40 R with a desired linear polarization (e.g., a vertical or horizontal polarization). If desired, multiple feed probes  78  may be formed on multiple sidewalls  94  of dielectric resonating element  92  to configure antennas  40 F and  40 R to cover multiple orthogonal linear polarizations at once. The phase of each feed probe may be independently adjusted over time to provide the antenna with other polarizations such as an elliptical or circular polarization if desired. Feed probes  78  may sometimes be referred to herein as feed conductors  78 , feed patches  78 , or probe feeds  78 . Dielectric resonating element  92  may sometimes be referred to herein as a dielectric radiating element, dielectric radiator, dielectric resonator, dielectric antenna resonating element, dielectric column, dielectric pillar, radiating element, or resonating element. 
     In this way, dielectric resonating element  92  may be used to form both a front-facing antenna  40 F for a front-facing phased antenna array and a rear-facing antenna  40 R for a rear-facing phased antenna array in device  10 . If desired, printed circuit  74  may include a respective opening  76  for each dielectric resonating element  92 .  FIG.  7    is a top view showing one example of how printed circuit  74  may include a respective opening  76  for each dielectric resonating element  92  in the front and rear-facing phased antenna arrays. 
     In the example of  FIG.  7   , the front and rear-facing phased antenna arrays each include three antennas formed from three dielectric resonating elements  92 - 1 ,  92 - 2 , and  92 - 3  arranged in a one-dimensional array pattern (e.g., dielectric resonating element  92 - 1  may form a first front-facing antenna and a first rear-facing antenna, dielectric resonating element  92 - 2  may form a second front-facing antenna and a second rear-facing antenna, etc.). As shown in  FIG.  7   , printed circuit  74  may completely surround (enclose) a respective opening  76  for each dielectric resonating element  92  (e.g., dielectric resonating element  92 - 1  may be mounted within opening  76 - 1 , dielectric resonating element  92 - 2  may be mounted within opening  76 - 2 , etc.). In other words, openings  76  may be closed slots within printed circuit  74 . 
     The example of  FIG.  7    is merely illustrative. If desired, each dielectric resonating element may be located within the same opening  76 , as shown in the example of  FIG.  8   . In another implementation, each opening  76  may be an open slot in printed circuit  74 , as shown in the example of  FIG.  9   . As shown in  FIG.  9   , printed circuit  74  may surround some but not all sides of openings  76 - 1 ,  76 - 2 , and  76 - 3 . In other words, printed circuit  74  may be a comb-shaped PCB where openings  76 - 1 ,  76 - 2 , and  76 - 3  are formed from notches in a given edge of printed circuit  74 . The examples of  FIGS.  7 - 9    are merely illustrative. Printed circuit  74  may surround any desired number of openings  76 . The front and rear-facing phased antenna arrays may include any desired number of antennas formed using any desired number of dielectric resonating elements arranged in any desired array pattern. 
       FIG.  10    is a top-down view (e.g., as taken in the −Z direction of  FIG.  6   ) of a given dielectric resonating element  92  showing how different feed probes  78  may be used to feed front-facing antenna  40 F and rear-facing antenna  40 R, respectively. In the example of  FIG.  10   , printed circuit  74  and dielectric overmold  86  have been omitted for the sake of clarity. 
     As shown in  FIG.  10   , dielectric resonating element  92  may be fed by a first feed probe  78  such as feed probe  78 F for the front-facing antenna and may be fed by a second feed probe such as feed probe  78 R for the rear-facing antenna (e.g., antennas  40 F and  40 R of  FIG.  6   ). Feed probe  78 F may include a feed conductor  102  that contacts a first sidewall  94  and feed probe  78 R may include a second feed conductor  102  that contacts a second sidewall  94  of dielectric resonating element  92 . Feed probes  78 F and  78 R may each include a respective conductive portion  104  (e.g., a conductive trace) coupled to respective signal conductors in printed circuit  74  via conductive interconnect structures  80  of  FIG.  6   . 
     In the example of  FIG.  10   , feed probes  78 F and  78 R are coupled to opposing sidewalls  94  of dielectric resonating element  92 . Feed probes  78 F and  78 R of  FIG.  10    may therefore convey radio-frequency signals with the same linear polarization. In another implementation, feed probes  78 R and  78 F may be coupled to orthogonal sidewalls  94  of dielectric resonating element  92 . In yet another implementation, feed probes  78 R and  78 F may be coupled to the same sidewall  94  of dielectric resonating element  92 . If desired, the front-facing and rear-facing antennas may convey radio-frequency signals using orthogonal linear polarizations. 
       FIG.  11    is a top-down view of dielectric resonating element  92  in an example where the front-facing and rear-facing antennas each convey radio-frequency signals using orthogonal linear polarizations. As shown in  FIG.  11   , the front-facing antenna may be fed using feed probes  78 FH and  78 FV whereas the rear-facing antenna is fed using feed probes  78 RV and  78 RH. Feed probes  78 FH and  78 FV may be mounted to orthogonal sidewalls  94  of dielectric resonating element  92 . Feed probes  78 RV and  78 FV may be mounted to opposing sidewalls  94  of dielectric resonating element  92 . Feed probes  78 RH and  78 FH may be mounted to opposing sidewalls  94  of dielectric resonating element  92 . Feed probes  78 RV and  78 RH may be mounted to orthogonal sidewalls  94  of dielectric resonating element  92 . In this way, feed probe  78 FV may convey vertically-polarized radio-frequency signals for the front-facing antenna, feed probe  78 RV may convey vertically-polarized radio-frequency signals for the rear-facing antenna, feed probe  78 FH may convey horizontally-polarized radio-frequency signals for the front-facing antenna, and feed probe  78 RH may convey horizontally-polarized radio-frequency signals for the rear-facing antenna. The example of  FIG.  11    is merely illustrative. If desired, feed probe  78 RV may be coupled to the same sidewall  94  as feed probe  78 FV and/or feed probe  78 RH may be coupled to the same sidewall  94  as feed probe  78 FH. 
       FIG.  12    is a cross-sectional side view showing one example of how feed probes  78 F and  78 R may feed respective portions of dielectric resonating element  92  (e.g., for front-facing antenna  40 F and rear-facing antenna  40 R, respectively). As shown in  FIG.  12   , feed probe  78 F for front-facing antenna  40 F may contact a first sidewall  94  of dielectric resonating element  92 . Feed probe  78 R for rear-facing antenna  40 R may contact a second sidewall  94  of dielectric resonating element  92  opposite the first sidewall  94 . Feed probes  78 F and  78 R may be used to form feed probes  78 FH and  78 RH of  FIG.  11   , respectively, or may be used to form feed probes  78 FV and  78 FV of  FIG.  11   , respectively, in scenarios where antennas  40 F and  40 R cover multiple polarizations. 
     If desired, notches such as notches  110  may be formed in sidewalls  94  at or around central axis  100 . The geometry of notches  110  may help to isolate the electromagnetic modes of dielectric resonating element  92  used to propagate radio-frequency signals  88  for front-facing antenna  40 F from the electromagnetic modes of dielectric resonating element  92  used to propagate radio-frequency signals  90  for rear-facing antenna  40 R. If desired, feed probes  78 F and  78 R may each be coupled to dielectric resonating element  92  within notches  110  (e.g., feed probes  78 F and  78 R may be mounted within notches  110 ). 
     In order to further isolate front-facing antenna  40 F from rear-facing antenna  40 R, feed probes  78 F and  78 R may be mounted to dielectric resonating element  92  with opposing (e.g., inverted or flipped) orientations. In the example of  FIG.  12   , the feed conductor  102  for feed probe  78 F is an L-shaped feed conductor having a first portion  106  in contact with dielectric resonating element  92  and a second portion  108  extending away from first portion  106 . Second portion  108  may be coupled to a given conductive interconnect structure  80  on printed circuit  74  ( FIG.  6   ). Similarly, the feed conductor  102  for feed probe  78 R is an L-shaped feed conductor having a first portion  106  in contact with dielectric resonating element  92  and a second  108  extending away from first portion  106 . The feed conductors  102  of  FIG.  12    may be formed from pieces of sheet metal that are folded into an L-shape, for example. Because feed probes  78 F and  78 R have opposite orientations, the second portion  108  of feed probe  78 F and the second portion  108  of feed probe  78 R are located on opposing sides of central axis  100 . This may configure feed probe  78 R to more easily excite the electromagnetic modes of dielectric resonating element  92  between central axis  100  and bottom surface  82  (for propagating radio-frequency signals  90 ) and may configure feed probe  78 F to more easily excite the electromagnetic modes of dielectric resonating element  92  between central axis  100  and top surface  84  (for propagating radio-frequency signals  88 ), thereby helping to isolate front-facing antenna  40 F from rear-facing antenna  40 R. 
     The example of  FIG.  12    is merely illustrative. Feed conductors  102  may have other shapes (e.g., may be folded into a T-shape or other shapes instead of an L-shape). More (e.g., all) of feed probe  78 R may be located below central axis  100  than feed probe  78 F and more (e.g., all) of feed probe  78 F may be located above central axis  100  than feed probe  78 R if desired. In implementations where feed probes  78 F and  78 R include conductive material patterned directly onto dielectric resonating element  92 , the point on the feed conductor  102  for feed probe  78 F located closest to bottom surface  82  may be coupled to printed circuit  74  whereas the point on the feed conductor  102  for feed probe  78 R located closest to top surface  84  may be coupled to printed circuit  74 . Notches  110  may have other shapes having edges that follow any path having any desired number of curved and/or straight segments. Feed probes  78 F and  78 R may be coupled to sidewalls  94  outside of notches  110 . If desired, feed probes  78 F and  78 R may be coupled to the same sidewall  94  of dielectric resonating element  92  (e.g., within notch  110  or at opposing sides of notch  110 ). 
       FIG.  13    is a cross-sectional side view showing one example of how feed probes  78 F and  78 R may be coupled to the same sidewall  94  of dielectric resonating element  92 . As shown in  FIG.  13   , feed probes  78 F and  78 R may be coupled to the same sidewall  94  of dielectric resonating element  92 . If desired, feed probes  78 F and  78 R may have inverted orientations about central axis  100  to help isolate the front-facing and rear-facing electromagnetic modes of the dielectric resonating element. When oriented in this way, the sides of feed probes  78 F and  78 R closest to central axis  100  may be coupled to printed circuit  74 . If desired, dielectric resonating element  92  may include a notch such as notch  112  between feed probes  78 F and  78 R (e.g., at or extending through central axis  100 ) to help further isolate the front and rear-facing antennas. If desired, notch  112  may extend around all sides of dielectric resonating element  92  (e.g., running within the X-Y plane around longitudinal axis  98 , leaving only central portion  114  connecting the portion of dielectric resonating element  92  above central axis  100  from the portion of dielectric resonating element  92  below central axis  100 ). 
     The example of  FIG.  13    is merely illustrative. Notch  112  may have other shapes (e.g., shapes having edges that follow any path having any desired number of curved and/or straight segments). Feed probes  78 F and  78 R may have other shapes (e.g., may be formed from sheet metal folded in a T-shape, may be formed from conductive traces patterned directly onto sidewall  94 , etc.). Notch  112  may be omitted. If desired, feed probe  78 F may be mounted to the sidewall  94  opposite to feed probe  78 R (e.g., at location  116 ). If desired, feed probe  78 R may be mounted to the sidewall  94  opposite to feed probe  78 F (e.g., at location  118 ). Notch  112  may be filled with dielectric material if desired (e.g., portions of dielectric overmold  86  of  FIG.  6   ). 
     Sidewalls  94  may have other shapes. If desired, the same feed probe may be used to feed both the front and rear-facing antennas (e.g., where the feed probe is positioned at a particular location on the dielectric resonating element and has a particular shape that, when combined with the geometry of the dielectric resonating element, the feed probe excites separate front and rear-facing electromagnetic modes of the dielectric resonating element to allow the front and rear-facing antennas to be independently operated). 
     The examples of  FIGS.  6 - 13    in which antennas  40 F and  40 R are formed from the same dielectric resonating element are merely illustrative. If desired, antennas  40 F and  40 R may be formed from respective dielectric resonating elements separated by an interposer substrate, as shown in the example of  FIG.  14   . As shown in  FIG.  14   , front-facing antenna  40 F may include a front-facing dielectric resonating element  92 F and rear-facing antenna  40 R may include a rear-facing dielectric resonating element  92 R. Dielectric resonating elements  92 R and  92 F may be mounted to opposing sides of an interposer substrate such as substrate  120 . Dielectric resonating element  92 F may be fed using a feed probe  78 F at a first side of substrate  120 . Dielectric resonating element  92 R may be fed using a feed probe  78 R at a second side of substrate  120 . Substrate  120  may help to isolate front-facing antenna  40 F from rear-facing antenna  40 R. 
     Device  10  may gather and/or use personally identifiable information. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     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: 20210420
Publication Date: 20250121
Grant Date: 20250121
Priority Date: 20210420
Inventors: Compton, Lucas R.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q3/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q25/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q3/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0277", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0492", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q25/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q3/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/241", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/0492", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/50", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q5/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q3/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/22", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 83446994