Patent Publication Number: US-11664601-B2

Title: Electronic devices with coexisting antennas

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless circuitry. 
     Electronic devices often include wireless 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 may support high bandwidths but may raise significant challenges. For example, the presence of conductive electronic device components and other antenna elements can also make it difficult to incorporate circuitry for handling millimeter and centimeter wave communications into the electronic device, especially in compact devices having limited interior space. In addition, if care is not taken, manufacturing variations can undesirably impact the mechanical reliability of the antennas in the electronic device, and different antennas may undesirably impact each other. 
     It would therefore be desirable to be able to provide electronic devices with improved components for supporting millimeter and centimeter wave communications and wireless communications in general. 
     SUMMARY 
     An electronic device may be provided with a housing, a display, and wireless circuitry. The housing may include peripheral conductive housing structures that run around a periphery of the device. The display may include a display cover layer mounted to the peripheral conductive housing structures. An antenna ground (e.g., ground structures) may be separated from the peripheral conductive housing structures by a slot. The wireless circuitry may include a phased antenna array that conveys radio-frequency signals in one or more frequency bands between 10 GHz and 300 GHz. The phased antenna array may convey the radio-frequency signals through the display cover layer or other dielectric cover layers in the device. 
     A phased antenna array may be formed from dielectric resonator antennas disposed within the antenna module. The dielectric resonator antennas may include dielectric columns excited by feed probes. The antenna module may be mounted in the slot between the peripheral conductive housing structures and the antenna ground by an attachment structure (e.g., by a screw in the attachment structure). The peripheral conductive housing structures and the antenna ground may form an additional antenna. A tunable element for the additional antenna may be coupled across the slot. The screw may form a conductive path from the peripheral conductive housing structures to the tunable element. 
     A flexible printed circuit may include transmission lines coupled to the feed probes to feed the dielectric resonator antennas. The transmission lines may be separated from each other using corresponding fences of conductive vias in the flexible printed circuit. The flexible printed circuit may have a first end coupled to the antenna module and extending towards peripheral conductive housing structures forming the additional antenna and a second end coupled to transceiver circuitry. Ground traces on the flexible printed circuit may be shorted to ground structures at the first and second ends to improve the antenna efficiency of the additional antenna. The flexible printed circuit may include an elongated slot with overlapping conductive structures and laterally surrounded by a fence of conductive vias to improve the flexibility of the flexible printed circuit while providing satisfactory antenna performance. 
    
    
     
       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 that may be adjusted using control circuitry to direct a beam of signals 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 perspective view of an illustrative prob-fed dielectric resonator antenna for covering multiple polarizations in accordance with some embodiments. 
         FIG.  7    is a perspective view of an illustrative antenna module having dielectric resonator antennas with feed probes in accordance with some embodiments. 
         FIG.  8    is a top-down view of an illustrative electronic device having an antenna module aligned with a notch in a display module in accordance with some embodiments. 
         FIG.  9    is a top-down view of an illustrative electronic device having an antenna module coupled to a slotted printed circuit and integrated with additional antenna elements in accordance with some embodiments. 
         FIG.  10    is a top-down view of a slot portion of an illustrative slotted printed circuit in accordance with some embodiments. 
         FIG.  11    is a cross-sectional view of a portion of an illustrative slotted printed circuit that is coupled to ground structures in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG.  1    may contain wireless circuitry. The wireless circuitry may include one or more antennas. The antennas may include phased antenna arrays that are used for performing wireless communications 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. 
     Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, 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  (e.g., display  14  may form some or all of the front face of the device). 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. 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 dielectrics. 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). 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, 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 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 such as notch  8  that extends into active area AA. 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.). The display module may have a recess or notch in upper region  20  of device  10  that is free from active display circuitry (i.e., that forms notch  8  of inactive area IA). Notch  8  may be a substantially rectangular region that is surrounded (defined) on three sides by active area AA and on a fourth side by peripheral conductive housing structures  12 W. 
     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  in notch  8  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 backplate) that spans the walls of housing  12  (i.e., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of peripheral conductive housing structures  12 W). The backplate may form an exterior rear surface of device  10  or may be covered by layers such as thin cosmetic layers, protective coatings, and/or other coatings that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide the backplate from view of the user. Device  10  may also include conductive structures such as printed circuit boards, components mounted on printed circuit boards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device  10 , may extend under active area AA of display  14 , for example. 
     In regions  22  and  20 , openings may be formed within the conductive structures of device  10  (e.g., between peripheral conductive housing structures  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 . 
     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., ends at regions  22  and  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 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. Gaps  18  may be omitted 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 (as an example). An upper antenna may, for example, be formed at the upper end of device  10  in region  20 . A lower antenna may, for example, be formed at the lower end of device  10  in region  22 . Additional antennas may be formed along the edges of housing  12  extending between regions  20  and  22  if desired. 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 and/or 5th generation mobile networks or 5 th  generation wireless systems (5G) communications bands between 27 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.). 
     If desired, 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 signals 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. Millimeter/centimeter wave transceiver circuitry  38  may additionally or alternatively perform bidirectional communications with external wireless equipment. 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 . Non-millimeter/centimeter wave transceiver circuitry  36  may include wireless local area network (WLAN) transceiver circuitry that handles 2.4 GHz and 5 GHz bands for Wi-Fi® (IEEE 802.11) communications, wireless personal area network (WPAN) transceiver circuitry that handles the 2.4 GHz Bluetooth® communications band, cellular telephone transceiver circuitry that handles cellular telephone communications bands from 700 to 960 MHz, 1710 to 2170 MHz, 2300 to 2700 MHz, and/or or any other desired cellular telephone communications bands between 600 MHz and 4000 MHz, GPS receiver circuitry that receives GPS signals at 1575 MHz or signals for handling other satellite positioning data (e.g., GLONASS signals at 1609 MHz), television receiver circuitry, AM/FM radio receiver circuitry, paging system transceiver circuitry, ultra-wideband (UWB) transceiver circuitry, near field communications (NFC) circuitry, etc. 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. Non-millimeter/centimeter wave transceiver circuitry  36  may be omitted if desired. 
     Wireless circuitry  34  may include antennas  40 . Non-millimeter/centimeter wave transceiver circuitry  36  may convey radio-frequency signals below 10 GHz using one or more antennas  40 . Millimeter/centimeter wave transceiver circuitry  38  may convey radio-frequency signals above 10 GHz (e.g., at millimeter wave and/or centimeter wave frequencies) using antennas  40 . In general, transceiver circuitry  36  and  38  may be configured to cover (handle) any suitable communications (frequency) bands of interest. The transceiver circuitry may convey radio-frequency signals using 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 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. A codebook on device  10  may map each beam pointing angle to a corresponding set of phase and magnitude values to be provided to phase and magnitude controllers  50  (e.g., the control circuitry may generate control signals  52  based on information from the codebook). 
     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  64  (sometimes referred to as a display panel or conductive display structures). Display module  64  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  64 . Display module  64  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  64  may form inactive area IA of display  14 . 
     Device  10  may include multiple phased antenna arrays (e.g., phased antenna arrays  54  of  FIG.  4   ). For example, device  10  may include a rear-facing phased antenna array. The rear-facing phased antenna array 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 rear-facing phased antenna array may transmit and/or 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). The rear-facing phased antenna array may perform beam steering for radio-frequency signals  60  across at least some of the hemisphere below the rear face of device  10 . 
     The field of view of the rear-facing phased antenna array is limited to the hemisphere under the rear face of device  10 . Display module  64  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 a front-facing 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  64  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, particularly as the size of active area AA is maximized. 
     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  64  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  64 . The front-facing phased antenna array may transmit and/or receive radio-frequency signals  62  at millimeter and centimeter wave frequencies through display cover layer  56 . The front-facing phased antenna array may perform beam steering for radio-frequency signals  62  across at least some of the hemisphere above the front face of device  10 . 
     Device  10  may include both a front-facing phased antenna array (e.g., within peripheral region  66 ) and a rear-facing phased antenna array (e.g., within peripheral region  66  or elsewhere between display module  64  and rear housing wall  12 R). If desired, device  10  may additionally or alternatively include one or more side-facing phased antenna arrays. The side-facing phased antenna arrays may be aligned with dielectric antenna windows in peripheral conductive housing structures  12 W. The front, rear, and/or side-facing phased antenna arrays may be omitted if desired. The front and rear-facing phased antenna arrays (and optionally the side-facing phased antenna arrays) may collectively provide radio-frequency cover across an entire sphere around device  10 . 
     The phased antenna array(s)  54  in device  10  may be formed in corresponding integrated antenna modules. Each antenna module may include a substrate such as a rigid printed circuit board substrate, a flexible printed circuit substrate, a plastic substrate, or a ceramic substrate, and one or more phased antenna arrays mounted to the substrate. Each antenna module may also include electronic components (e.g., radio-frequency components) that support the operations of the phased antenna array(s) therein. For example, each antenna module may include a radio-frequency integrated circuit (e.g., an integrated circuit chip) or other circuitry mounted to the corresponding substrate. Transmission line structures (e.g., radio-frequency signal traces), conductive vias, conductive traces, solder balls, or other conductive interconnect structures may couple the radio-frequency integrated circuit to each of the antennas in the phased antenna array(s) of the antenna module. The radio-frequency integrated circuit (RFIC) and/or other electronic components in the antenna module may include radio-frequency components such as amplifier circuitry, phase shifter circuitry (e.g., phase and magnitude controllers  50  of  FIG.  4   ), and/or other circuitry that operates on radio-frequency signals. The rear-facing, front-facing, and/or side-facing phased antenna array(s) in device  10  may be formed within respective antenna modules. In another suitable arrangement, a rear-facing and front-facing phased antenna array may be formed as a part of the same antenna module in device  10 . 
       FIG.  6    is a perspective view of an illustrative probe-fed dielectric resonator antenna that may be used in forming the antennas of any of the phased antenna arrays in device  10 . Antenna  40  of  FIG.  6    may be a dielectric resonator antenna. In this example, antenna  40  includes a dielectric resonating element  68  mounted to an underlying substrate such as substrate  72 . Substrate  72  may, for example, be the substrate of a corresponding antenna module in device  10 . Substrate  72  may be a rigid printed circuit board substrate, a flexible printed circuit substrate, a ceramic substrate, a plastic substrate, or any other desired substrate. 
     In the example of  FIG.  6   , antenna  40  is a dual-polarization antenna that conveys both vertically and horizontally polarized radio-frequency signals  84  (e.g., linearly-polarized signals having orthogonal electric field orientations). This example is merely illustrative and, in another suitable arrangement, antenna  40  may only cover a single polarization. Antenna  40  may be fed using radio-frequency transmission lines that are formed on and/or embedded within flexible substrate  72  such as radio-frequency transmission lines  88  (e.g., a first radio-frequency transmission line  88 V for conveying vertically-polarized signals and a second radio-frequency transmission line  88 H for conveying horizontally-polarized signals). Radio-frequency transmission lines  88 V and  88 H may, for example, form part of radio-frequency transmission lines  42  of  FIGS.  3  and  4   . Radio-frequency transmission lines  88 V and  88 H may include ground traces (e.g., for forming part of ground conductor  48  of  FIG.  3   ) and signal traces (e.g., for forming part of signal conductor  46  of  FIG.  3   ) on and/or embedded within substrate  72 . Radio-frequency transmission lines  88 V and  88 H may be coupled to a radio-frequency integrated circuit or other radio-frequency components on the antenna module that includes antenna  40 . 
     Dielectric resonating element  68  of antenna  40  may be formed from a column (pillar) of dielectric material mounted to the top surface of substrate  72 . If desired, dielectric resonating element  68  may be embedded within (e.g., laterally surrounded by) a dielectric substrate mounted to the top surface of substrate  72  such as dielectric substrate  70 . Dielectric resonating element  68  may have a height  96  that extends from a bottom surface  82  at substrate  72  to an opposing top surface  80 . Dielectric substrate  70  (sometimes referred to herein as over-mold structure  70 ) may extend across some or all of height  96 . Top surface  80  may lie flush with the top surface of dielectric substrate  70 , may protrude beyond the top surface of dielectric substrate  70 , or dielectric substrate  70  may extend over and cover top surface  80  of dielectric resonating element  68 . 
     The operating (resonant) frequency of antenna  40  may be selected by adjusting the dimensions of dielectric resonating element  68  (e.g., in the direction of the X, Y, and/or Z axes of  FIG.  6   ). Dielectric resonating element  68  may be formed from a column of dielectric material having dielectric constant dk 1 . Dielectric constant dk 1  may be relatively high (e.g., greater than 10.0, greater than 12.0, greater than 15.0, greater than 20.0, between 22.0 and 25.0, 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  68  may be formed from zirconia or a ceramic material. Other dielectric materials may be used to form dielectric resonating element  68  if desired. 
     Dielectric substrate  70  may be formed from a material having dielectric constant dk 2 . Dielectric constant dk 2  may be less than dielectric constant dk 1  of dielectric resonating element  68  (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 dk 2  may be less than dielectric constant dk 1  by at least 10.0, 5.0, 15.0, 12.0, 6.0, etc. In one suitable arrangement, dielectric substrate  70  may be formed from molded plastic (e.g., injection molded plastic). Other dielectric materials may be used to form dielectric substrate  70  or dielectric substrate  70  may be omitted if desired. The difference in dielectric constant between dielectric resonating element  68  and dielectric substrate  70  may establish a radio-frequency boundary condition between dielectric resonating element  68  and dielectric substrate  70  from bottom surface  82  to top surface  80 . This may configure dielectric resonating element  68  to serve as a resonating waveguide for propagating radio-frequency signals  84  at millimeter and centimeter wave frequencies. 
     Dielectric substrate  70  may have a width (thickness)  94  on some or all sides of dielectric resonating element  68 . Width  94  may be selected to isolate dielectric resonating element  68  from surrounding device structures and/or from other dielectric resonating elements in the same antenna module and to minimize signal reflections in dielectric substrate  70 . Width  94  may be, for example, at least one-tenth of the effective wavelength of the radio-frequency signals in a dielectric material of dielectric constant dk 2 . Width  94  may be 0.4-0.5 mm, 0.3-0.5 mm, 0.2-0.6 mm, greater than 0.1 mm, greater than 0.3 mm, 0.2-2.0 mm, 0.3-1.0 mm, or greater than between 0.4 and 0.5 mm, just as a few examples. 
     Dielectric resonating element  68  may radiate radio-frequency signals  84  when excited by the signal conductor for radio-frequency transmission lines  88 V and/or  88 H. In some scenarios, a slot is formed in ground traces on substrate  72 , the slot is indirectly fed by a signal conductor embedded within substrate  72 , and the slot excites dielectric resonating element  68  to radiate radio-frequency signals  84 . However, in these scenarios, the radiating characteristics of the antenna may be affected by how the dielectric resonating element is mounted to substrate  72 . For example, air gaps or layers of adhesive used to mount the dielectric resonating element to the flexible printed circuit can be difficult to control and can undesirably affect the radiating characteristics of the antenna. In order to mitigate the issues associated with exciting dielectric resonating element  68  using an underlying slot, antenna  40  may be fed using one or more radio-frequency feed probes  100  such as feed probes  100 V and  100 H of  FIG.  6   . Feed probes  100  may form part of the antenna feeds for antenna  40  (e.g., antenna feed  44  of  FIG.  3   ). 
     As shown in  FIG.  6   , feed probe  100 V may be formed from conductive structure  86 V and feed probe  100 H may be formed from conductive structure  86 H. Conductive structure  86 V may include a first portion patterned onto or pressed against a first sidewall  102  of dielectric resonating element  68 . If desired, conductive structure  86 V may also include a second portion on the surface of substrate  72  and the second portion may be coupled to the signal traces of radio-frequency transmission line  88 V (e.g., using solder, welds, conductive adhesive, etc.). The second portion of conductive structure  86 V may be omitted if desired (e.g., the signal traces in radio-frequency transmission line  88 V may be soldered directly to the portion of conductive structure  86 V on the first sidewall  102 ). Conductive structure  86 V may include conductive traces patterned directly onto the first sidewall  102  or may include stamped sheet metal in scenarios where conductive structure  86 V is pressed against the first sidewall  102 , as examples. 
     The signal traces in radio-frequency transmission line  88 V may convey radio-frequency signals to and from feed probe  100 V. Feed probe  100 V may electromagnetically couple the radio-frequency signals on the signal traces of radio-frequency transmission line  88 V into dielectric resonating element  68 . This may serve to excite one or more electromagnetic modes (e.g., radio-frequency cavity or waveguide modes) of dielectric resonating element  68 . When excited by feed probe  100 V, the electromagnetic modes of dielectric resonating element  68  may configure the dielectric resonating element to serve as a waveguide that propagates the wavefronts of radio-frequency signals  84  along the height of dielectric resonating element  68  (e.g., in the direction of the Z-axis and along the central/longitudinal axis  76  of dielectric resonating element  68 ). The radio-frequency signals  84  conveyed by feed probe  100 V may be vertically polarized. 
     Similarly, conductive structure  86 H may include a first portion patterned onto or pressed against a second sidewall  102  of dielectric resonating element  68 . If desired, conductive structure  86 H may also include a second portion on the surface of substrate  72  and the second portion may be coupled to the signal traces of radio-frequency transmission line  88 H (e.g., using solder, welds, conductive adhesive, etc.). The second portion of conductive structure  86 H may be omitted if desired (e.g., the signal traces in radio-frequency transmission line  88 H may be soldered directly to the conductive structure  86 H on sidewall  102 ). Conductive structure  86 H may include conductive traces patterned directly onto the second sidewall  102  or may include stamped sheet metal in scenarios where conductive structure  86 H is pressed against the second sidewall  102 , as examples. 
     The signal traces in radio-frequency transmission line  88 H may convey radio-frequency signals to and from feed probe  100 H. Feed probe  100 H may electromagnetically couple the radio-frequency signals on the signal traces of radio-frequency transmission line  88 H into dielectric resonating element  68 . This may serve to excite one or more electromagnetic modes (e.g., radio-frequency cavity or waveguide modes) of dielectric resonating element  68 . When excited by feed probe  100 H, the electromagnetic modes of dielectric resonating element  68  may configure the dielectric resonating element to serve as a waveguide that propagates the wavefronts of radio-frequency signals  84  along the height of dielectric resonating element  68  (e.g., along central/longitudinal axis  76  of dielectric resonating element  68 ). The radio-frequency signals  84  conveyed by feed probe  100 H may be horizontally polarized. 
     Similarly, during signal reception, radio-frequency signals  84  may be received by antenna  40 . The received radio-frequency signals may excite the electromagnetic modes of dielectric resonating element  68 , resulting in the propagation of the radio-frequency signals down the height of dielectric resonating element  68 . Feed probe  100 V may couple the received vertically-polarized signals onto radio-frequency transmission line  88 V. Feed probe  100 H may couple the received horizontally-polarized signals onto radio-frequency transmission line  88 H. Radio-frequency transmission lines  88 H and  88 V may pass the received radio-frequency signals to millimeter/centimeter wave transceiver circuitry (e.g., millimeter/centimeter wave transceiver circuitry  38  of  FIGS.  2  and  3   ) through the radio-frequency integrated circuit for antenna  40 . The relatively large difference in dielectric constant between dielectric resonating element  68  and dielectric substrate  70  may allow dielectric resonating element  68  to convey radio-frequency signals  84  with a relatively high antenna efficiency (e.g., by establishing a strong boundary between dielectric resonating element  68  and dielectric substrate  70  for the radio-frequency signals). The relatively high dielectric constant of dielectric resonating element  68  may also allow the dielectric resonating element  68  to occupy a relatively small volume compared to scenarios where materials with a lower dielectric constant are used. 
     The dimensions of feed probes  100 V and  100 H (e.g., height  90  and width  92  on sidewalls  102 ) may be selected to help match the impedance of radio-frequency transmission lines  88 V and  88 H to the impedance of dielectric resonating element  68 . As an example, width  92  may be between 0.3 mm and 0.7 mm, between 0.2 mm and 0.8 mm, between 0.4 mm and 0.6 mm, or other values. Height  90  may be between 0.3 mm and 0.7 mm, between 0.2 mm and 0.8 mm, between 0.4 mm and 0.6 mm, or other values. Height  90  may be equal to width  92  or may be different than width  92 . Feed probes  100 V and  100 H may sometimes be referred to herein as feed conductors, feed patches, or probe feeds. Dielectric resonating element  68  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. When fed by one or more feed probes such as feed probes  100 V and  100 H, dielectric resonator antennas such as antenna  40  of  FIG.  6    may sometimes be referred to herein as probe-fed dielectric resonator antennas. 
     Antenna  40  may be included in a rear-facing, front-facing, or side-facing phased antenna array in device  10  (e.g., radio-frequency signals  84  may form radio-frequency signals  62  or  60  of  FIG.  5   ). In scenarios where antenna  40  is formed in a front-facing phased antenna array, top surface  80  may be pressed against, adhered to, or separated from display cover layer  56  of  FIG.  5   . In scenarios where antenna  40  is formed in a rear-facing phased antenna array, top surface  80  may be pressed against, adhered to, or separated from rear housing wall  12 R of  FIG.  5   . An optional impedance matching layer may be interposed between top surface  80  and rear housing wall  12 R or display cover layer  56 . The impedance matching layer may have a dielectric constant that is between dielectric constant dk 1  and the dielectric constant of rear housing wall  12 R or display cover layer  56 . If desired, the dielectric constant and thickness of the impedance matching layer may be selected to configure the impedance matching layer to form a quarter-wave impedance transformer for antenna  40  at the frequencies of operation of antenna  40 . This may configure the impedance matching layer to help minimize signal reflections at the interfaces between top surface  80  and free space exterior to device  10 . 
     If desired, radio-frequency transmission lines  88 V and  88 H may include impedance matching structures (e.g., transmission line stubs) to help match the impedance of dielectric resonating element  68 . Both feed probes  100 H and  100 V may be active at once so that antenna  40  conveys both vertically and horizontally polarized signals at any given time. If desired, the phases of the signals conveyed by feed probes  100 H and  100 V may be independently adjusted so that antenna  40  conveys radio-frequency signals  84  with an elliptical or circular polarization. In another suitable arrangement, a single one of feed probes  100 H and  100 V may be active at once so that antenna  40  conveys radio-frequency signals of only a single polarization at any given time. In another suitable arrangement, antenna  40  may be a single-polarization antenna where radio-frequency transmission line  88 V and feed probe  100 V have been omitted. 
     As shown in  FIG.  6   , dielectric resonating element  68  may have a height  96 , a length  74 , and a width  73 . Length  74 , width  73 , and height  96  may be selected to provide dielectric resonating element  68  with a corresponding mix of electromagnetic cavity/waveguide modes that, when excited by feed probes  100 H and/or  100 V, configure antenna  40  to radiate at desired frequencies. For example, height  96  may be 2-10 mm, 4-6 mm, 3-7 mm, 4.5-5.5 mm, or greater than 2 mm. Width  73  and length  74  may each be 0.5-1.0 mm, 0.4-1.2 mm, 0.7-0.9 mm, 0.5-2.0 mm, 1.5 mm-2.5 mm, 1.7 mm-1.9 mm, 1.0 mm-3.0 mm, etc. Width  73  may be equal to length  74  (e.g., dielectric resonating element  68  may have a square-shaped lateral profile in the X-Y plane) or, in other arrangements, may be different than length  74  (e.g., dielectric resonating element  68  may have a rectangular or non-rectangular lateral profile in the X-Y plane). Sidewalls  102  of dielectric resonating element  68  may directly contact the surrounding dielectric substrate  70 . Dielectric substrate  70  may be molded over feed probes  100 H and  100 V or may include openings, notches, or other structures that accommodate the presence of feed probes  100 H and  100 V. Each sidewall  102  may be planar or, if desired, one or more sidewall  102  may have a non-planar shape (e.g., a shape with planar and curved portions, a planar shape with a notch or recessed portion, etc.). The example of  FIG.  6    is merely illustrative and, if desired, dielectric resonating element  68  may have other shapes (e.g., shapes with any desired number of straight and/or curved sidewalls  102 ). 
     If desired, antenna  40  in  FIG.  6    may include any other suitable elements. As an example, in order to mitigate cross polarization interference, parasitic elements onto the sidewalls of dielectric resonating element  68 . These parasitic elements may, for example, be formed from floating patches of conductive material patterned onto or pressed against the sidewalls of dielectric resonating element  68  (e.g., conductive patches that are not coupled to ground or the signal traces for antenna  40 ). In an illustrative arrangement, a first parasitic element may be patterned onto or pressed against a sidewall of dielectric resonating element  68  opposite feed probe  100 H (e.g., opposite the sidewall at which feed probe  100 H is disposed), and a second parasitic element may be patterned onto or pressed against a sidewall of dielectric resonating element  68  opposite feed probe  100 V (e.g., opposite the sidewall at which feed probe  100 V is disposed). 
     Phased antenna array  54  of  FIG.  4    (e.g., a front-facing phased antenna array for conveying radio-frequency signals  62  through display cover layer  56  of  FIG.  5   , a rear-facing phased antenna array for conveying radio-frequency signals  60  through rear housing wall  12 R of  FIG.  5   , or a side-facing phased antenna array) may include any desired number of antennas  40  arranged in any desired pattern (e.g., a pattern having rows and columns). Each of the antennas  40  in phased antenna array  54  may be dielectric resonator antenna such as the probe-fed dielectric resonator antenna  40  of  FIG.  6    (e.g., having two feed probes  100 V and  100 H as shown in  FIG.  6   , optionally with parasitic elements). Phased antenna array  54  may be formed as a part of an integrated antenna module. 
       FIG.  7    is a perspective view of an illustrative integrated antenna module that may include phased antenna array  54 . In the example of  FIG.  7   , substrate  72  is a flexible printed circuit. Phased antenna array  54  may include multiple dielectric resonating elements  68  embedded within dielectric substrate  70  to form antenna package  126 . Substrate  72  may include top and bottom opposing surfaces  122  and  124 . Antenna package  126  may be mounted on surface  122  of substrate  72  (e.g., may be surface-mounted to contact pads on surface  122 ). In the example of  FIG.  7   , phased antenna array  54  includes two low band antennas  40 L interleaved with two high band antennas  40 H (e.g., in a 1×4 array). This is merely illustrative and, in general, phased antenna array  54  may include any desired number of antennas for covering any desired frequency bands. The antennas may be arranged in any desired pattern. 
     As shown in  FIG.  7   , the dielectric resonating element  68 H in high band antennas  40 H may be separated from the dielectric resonating element  68 L in one or two adjacent low band antennas  40 L by distance  134 . Distance  134  may be selected to provide satisfactory electromagnetic isolation between low band antennas  40 L and high band antennas  40 H. Each dielectric resonating element  68  in phased antenna array  54  may be fed by feed probes having conductive structures  86 V and  86 H. Conductive structures  86 V and  86 H may be pressed against corresponding dielectric resonating elements  68  by feed probe biasing structures in antenna package  126  (not shown in  FIG.  7    for the sake of clarity). The feed probe biasing structures may, for example, press or bias conductive structure  86 H against the sidewalls  102  of dielectric resonating elements  68  (e.g., by exerting a biasing force in the −X direction). Similarly, the feed probe biasing structures may press or bias conductive structure  86 V against the sidewalls  102  of dielectric resonating elements  68  (e.g., by exerting a biasing force in the +Y direction). 
     Dielectric substrate  70  may be molded over the feed probe biasing structures as well as dielectric resonating elements  68 . Dielectric substrate  70  may have a bottom surface  130  at substrate  72  and an opposing top surface  132 . In the example of  FIG.  7   , the top surface  80  of dielectric resonating elements  68  protrudes above top surface  132  of dielectric substrate  70 . This is merely illustrative and, if desired, top surface  132  may lie flush with the top surface  80 . In another suitable arrangement, dielectric substrate  70  may cover the top surface  80  of dielectric resonating elements  70 . An attachment structure  128  may be partially embedded within dielectric substrate  70  (e.g., dielectric substrate  70  may be molded over part of attachment structure  128 ). Attachment structure  128  may help to secure antenna module  120  in place within device  10  if desired (e.g., using screws, pins, or other structures that extend through an opening in attachment structure  128 ). 
       FIG.  8    is a top-down view showing one illustrative location where antenna module  120  may be mounted within device  10  (e.g., antenna module  120  of  FIG.  7   ). As shown in  FIG.  8   , display module  64  in display  14  may include notch  8 . Display cover layer  56  of  FIG.  5    has been omitted from  FIG.  8    for the sake of clarity. Display module  64  may form active area AA of display  14  whereas notch  8  forms part of inactive area IA of display  14  ( FIG.  1   ). The edges of notch  8  may be defined by peripheral conductive housing structures  12 W and display module  64 . For example, notch  8  may have two or more edges (e.g., three edges) defined by display module  64  and one or more edges defined by peripheral conductive housing structures  12 W. 
     Device  10  may include speaker port  16  (e.g., an ear speaker) within notch  8 . If desired, device  10  may include other components  136  within notch  8 . Other components  136  may include one or more image sensors such as one or more cameras, an infrared image sensor, an infrared light emitter (e.g., an infrared dot projector and/or flood illuminator), an ambient light sensor, a fingerprint sensor, a capacitive proximity sensor, a thermal sensor, a moisture sensor, or any other desired input/output components (e.g., input/output devices  26  of  FIG.  2   ). Antenna module  120  (e.g., an antenna module having dielectric resonating elements  68 L interleaved with dielectric resonating elements  68 H for covering different frequency bands) may be mounted within device  10  (e.g., within peripheral region  66  of  FIG.  5   ) and aligned with the portion(s) of notch  8  that are not occupied by other components  136  or speaker port  16 . Antenna module  120  may be laterally interposed between two components  136  such as between an image sensor (e.g., a rear-facing camera) and an ambient light sensor, dot projector, flood illuminator, or ambient light sensor, for example. 
     Substrate  72  may extend under display module  64  to another substrate such as substrate  140  (e.g., another flexible printed circuit, a rigid printed circuit board, a main logic board, etc.). The radio-frequency transceiver circuitry (e.g., transceiver circuitry  38  in  FIGS.  2  and  3   ) for antenna module  120  may be mounted to substrate  140  if desired. Connector  123  (e.g. a board-to-board connector) on substrate  72  may be coupled to connector  138  (e.g., a board-to-board connector) on substrate  140 . The example of  FIG.  21    is merely illustrative and, in general, antenna module  120  may be mounted at any desired location within device  10 . Antenna module  120  may have any desired number of antennas for covering any desired frequency bands. The antennas in antenna module  120  may be arranged in any desired one or two-dimensional pattern. 
     By incorporating an antenna module such as antenna module  120  in the configuration shown in  FIG.  8   , antennas in antenna module  120  may cover at least some of the hemisphere over the front face of device  10  without occupying an excessive amount of space within device  10 . However, configured in this manner, antennas in antenna module  120  may be disposed in close proximity to other wireless communication circuitry (e.g., other antennas) and other components in device  10 . If care is not taken, these antennas and their corresponding elements may undesirably interfere with each other&#39;s operations. 
       FIG.  9    is top view of an illustrative configuration of device  10  having antennas in antenna module  120  (e.g., antennas  40 L and antennas  40 H in  FIG.  7   ) in close proximity to (e.g., adjacent to) antenna  40 ′. As shown in  FIG.  9   , device  10  may have peripheral conductive housing structures  12 W. Peripheral conductive housing structures  12 W may be divided by dielectric-filed peripheral gaps  18  (e.g., plastic gaps) such as gaps  18 - 1 ,  18 - 2 ,  18 - 3 . Gap  18 - 1  may divide peripheral conductive housing structures  12 W into segment  218  and segment  220 . Gap  18 - 2  may separate segment  220  from segment  222  of peripheral conductive housing structures  12 W. Gap  18 - 3  may separate segment  222  from segment  224  of peripheral conductive housing structures  12 W. 
     As shown in  FIG.  9   , device  10  may include multiple antennas  40  such as antenna  40 ′, antennas  40 L (in module  120 ), antennas  40 H (in module  120 ), and other antennas. If desired, these antennas may share ground structures  216 , which form at a portion of the antenna ground (e.g., the antenna ground coupled to ground connector  48  in  FIG.  3   ) for the antennas. 
     Ground structures  216  may be formed from conductive housing structures, from electrical device components in device  10 , from printed circuit board traces, from strips of conductor such as strips of wire and metal foil, from conductive portions of display  14  ( FIG.  1   ), and/or other conductive structures. In one suitable arrangement, ground structures  216  may include conductive portions of housing  12  (e.g., portions of rear housing wall  12 R of  FIG.  1    and/or portions of a different conductive support plate in device  10 ) and conductive portions of display  14  ( FIG.  1   ). Segments  218  and  224  of peripheral conductive housing structures  12 W may be coupled to ground structures  216  and may therefore form part of the antenna ground for one or more antennas in device  10 . Segments  218  and  224  and ground structures  216  may be formed from a single integral piece of metal if desired. 
     Segments  220  and  222  of peripheral conductive housing structures  12 W may be separated from ground structures  216  by dielectric-filled slot  150 . Air, plastic, ceramic, glass, and/or other dielectric materials may fill slot  150 . In one suitable arrangement, slot  150  may be continuous with gaps  18 - 1 ,  18 - 2 , and  18 - 3 , and a single piece of dielectric material (e.g., plastic) may fill slot  150 , gap  18 - 1 , gap  18 - 2 , and gap  18 - 3 . Dielectric material in slot  150  may lie flush with the exterior surface of device  10  if desired. 
     Antennas  40 ′,  40 L, and  40 H may be coupled to transceiver circuitry (e.g., corresponding transceiver circuitry  36  and/or  38 ) by corresponding radio-frequency transmission line paths (e.g., path  177  for antenna  40 ′ and paths  88  for antennas  40 L and  40 H). The transceiver circuitry may be mounted to a substrate such as logic board  140 . Logic board  140  may include a rigid printed circuit board, a flexible printed circuit, an integrated circuit, an integrated circuit package, and/or any other desired substrates. If desired, different transceiver circuitry (e.g., transceiver circuitry  36  and  38 ) may be mounted to different substrates. Filter circuitry, switching circuitry, or any other desired radio-frequency circuitry (not shown in  FIG.  9    for the sake of clarity) may be interposed on the radio-frequency transmission line paths between the corresponding transceiver circuitry and the antennas in device  10 . 
     Antenna  40 ′ may have an antenna resonating element  68 ′ that includes one or more antenna resonating element arms (e.g., a high band arm and a low band arm) formed from segment  220  of peripheral conductive housing structures  12 W. The length of segment  220  may be selected to provide antenna  40 ′ with response peaks in one or more communications bands. Antenna  40 ′ may have an antenna feed  176  with a positive antenna feed terminal  172  coupled to segment  220  and a ground antenna feed terminal  174  coupled to ground structures  216 . The length of segment  220  from antenna feed  176  to gap  18 - 1  and/or the length of segment  220  from antenna feed  176  to gap  18 - 2  may, for example, be approximately equal to one-quarter of an effective wavelength of operation of antenna  40 ′ (e.g., where the effective wavelength is equal to the free space wavelength modified by a constant value determined by the dielectric material in slot  106 ). Antenna  40 ′ may also have one or more harmonic modes and/or parasitic elements that cover additional frequencies. Slot  150  may also be a radiating slot that contributes to the frequency response of antenna  40 ′ (e.g., antenna  40 ′ may be a hybrid inverted-F slot antenna). 
     In the example of  FIG.  9   , antenna  40 ′ may operate in non-millimeter/centimeter wave frequency bands (e.g., at one or more frequency bands below 10 GHz). In particular, antenna feed  176  may be coupled to transceiver circuitry  36  (in  FIG.  2   ) using radio-frequency transmission line path  177 . Impedance matching circuitry such as a matching network may be interposed on radio-frequency transmission line path  177 . 
     Antenna  40 ′ may also include one or more tunable components such as a first tunable component  178  and a second tunable component  180  (e.g., tunable components configured to tune the frequency response of antenna  40 ′ for one or more frequency bands, to form return paths, to form open circuitry, etc.). Tunable component  178  may have a first terminal coupled to segment  220  at location  152  and a second (ground) terminal coupled to ground structures  216  at location  154 . Tunable component  180  may have a first terminal coupled to segment  220  at location  162  and a second (ground) terminal coupled to ground structures  216  at location  164 . Positive antenna feed terminal  172  may be interposed on segment  220  between locations  152  and  162 . 
     If desired, ground structures  216  may include multiple conductive structures such as one or more conductive layers within device  10 . For example, ground structures  216  may include a first conductive layer formed from a portion of housing  12  (e.g., a conductive backplate or support plate that forms part of rear housing wall  12 R of  FIG.  1   ) and a second conductive layer formed from a conductive display frame or support plate associated with display  14  ( FIG.  1   ). In these scenarios, conductive interconnect structures (e.g., conductive screws, conductive brackets, conductive clips, conductive pins, conductive springs, solder, welds, conductive adhesive, conductive screw bosses, etc.) may electrically connect ground terminals for antenna feeds (e.g., terminal  174  for antenna  40 ′) and/or tunable component terminals (e.g., ground terminals for component  178  and  180 ) to both the conductive display layer and the conductive housing layer. This may allow ground structures  216  to extend across both conductive portions of housing  12  and display  14  ( FIG.  1   ) so that the conductive material closest to antennas  40 ′ are held at a ground potential. This may, for example, serve to maximize the antenna efficiency of antenna  40 ′. 
     Antenna  40 ′ may be configured to cover any desired communications bands. In one suitable arrangement that is sometimes described herein as an example, antenna  40 ′ may convey radio-frequency signals in a cellular low band (e.g., between 617 and 960 MHz), a cellular low-mid band (e.g., between 1430 and 1510 MHz), a cellular mid band (e.g., between 1710 and 2170 MHz), a satellite navigation band (e.g., a GPS band between 1565 and 1605 MHz), and/or a cellular high band (e.g., between 2300 and 2700 MHz). Tunable component  178  may, for example, tune the frequency response of antenna  40 - 1  in the cellular midband and/or cellular low-midband. Tunable component  180  may, for example, tune the frequency response of antenna  40 - 1  in the cellular low band. In some configurations, the placement of antenna module  120  near antenna resonating element  68 ′ may cause loading effects on antenna  40 ′. If desired, component  180  may be configured to compensate for the loading of antenna module  120  on antenna  40 ′ (e.g., by include different sets of tunable components in scenarios where antenna module  120  is present or absent, by adjusting the different states of component  180  in scenarios where antenna module  120  is present or absent, etc.). This arrangement is merely illustrative. 
     Device  10  may include also include one or more antennas covering any other suitable communications bands (e.g., antennas other than antenna  40 ′ and antennas in antenna module  120 ). One or more of these antennas may be formed from slot  150 , segment  218 , segment  222 , segment  224 , or other structures in device  10 . These other antennas are not shown or described in detail in  FIG.  9    in order to not unnecessarily obscure the embodiments described herein. 
     Still referring to  FIG.  9   , antenna module  120  may be disposed within slot  150  between segment  220  of peripheral conductive housing structures  12 W and ground structure  216  (e.g., antenna module  120  may at least partially overlap slot  150 ). In particular, antenna module  120  may be disposed within slot  150  between a first portion of slot  150  across which antenna feed  176  for antenna  40 ′ is coupled and a second portion of slot  150  across which tunable component  180  for antenna  40 ′ is coupled. Arranged in this manner, antenna module  120  may also be aligned with notch  8  in the location as shown in  FIG.  8   . 
     An attachment structure  128  may be partially embedded in dielectric  70  of antenna module  120 . An exposed portion of attachment structure  128  (not embedded in dielectric  70 ) may have an opening through which a conductive structure such as screw  182  extends to secure antenna module  120  in place within device  10 . In the example of  FIG.  9   , a portion of attachment structure  128  (including screw  182 ) may form at least a portion of a conductive path through which a (non-ground) terminal of component  180  is coupled to segment  220  at location  162 . Because attachment structure  128  and screw  182  are used in combination, attachment structure  128  may be described to be include screw  182 . This configuration is merely illustrative. If desired, other conductive structures such as adhesive, pins, springs, clips, brackets, solder, welds, etc., may be used as part of attachment structure  128  to form the conductive path. If desired, the attachment structure  128  may form a conductive path between any other elements (e.g., other antenna elements for antenna  40 ′ such as antenna feed  176 , tunable component  178 , a ground terminal of tunable component  180 , for other antennas, etc.). 
     By sharing the use of attachment structure  128  (e.g., as a mechanical support structure for mounting antenna module  120 , as an electrical connector between elements of antenna  40 ′), value space may be conversed in region  20  ( FIG.  1   ) of device  10 , which is particularly advantageous given the large number of components in region  20 . Attachment structure  128  may be separated from resonating elements in antenna module  120  such as dielectric resonating element  68 H closest to attachment structure  128  by a suitable distance (e.g., a distance greater than 0.5 mm a distance between 0.5 and 0.6 mm, a distance, greater than 0.6 mm, etc.) to avoid an undesirable coupling between antennas in antenna module  120  and antenna  40 ′ through attachment structure  128 , as an example. If desired, attachment structure  128  may be suitably distanced from other (conductive) elements in device  10  to avoid an undesirable coupling to elements in antenna  40 ′ through attachment structure  128 . 
     In the example of  FIG.  9   , substrate  72  is a flexible printed circuit having transmission lines  88  and ground structures (e.g., ground traces) that form a portion of the antenna ground for one or more antennas in device  10 . A first end  72 - 1  of substrate  72  (sometimes referred to herein as a first end portion  72 - 2 ) may be coupled to antenna module  120  and a second end  72 - 2  of substrate  72  (sometimes referred to herein as a second end portion  72 - 2 ) may be coupled to substrate  140  (e.g., connector  123  on substrate  72  may be connected to connector  138  on substrate  140 ). Transmission lines  88  may be coupled to transceiver circuitry  38  ( FIG.  1   ), which may be mounted on substrate  140 , through connector  138  (e.g., and/or other conductive paths on substrate  140 . Accordingly, transmission lines  88  may be configured receive radio-frequency signals from transceiver circuitry  38  and to feed antennas in antenna module  120  (e.g., dielectric resonating elements  68  using corresponding feed probes). 
     In the illustrative configuration of  FIG.  9   , antenna module  120  includes four dual-polarization antennas, and substrate  72  includes eight transmission lines  88  (one for each of the two feed probes for each of the four antennas). This is merely illustrative. If desired, any desired number of antennas of one or more types and the corresponding number of transmission lines may be provided for antenna module  120 . 
     Substrate  140  may include ground structures forming a portion of the antenna ground (e.g., forming a portion of grounding structures  216  and/or connected to ground structures  216 ). The ground structures of substrate  140  and/or ground structures  216  may be connected to the ground structures such as ground traces on substrate  72  through connectors  123  and  138  at second end  72 - 2 . 
     Because antenna module  120  is disposed in slot  150 , first end  72 - 1 , which extends to antenna module  120 , also extends towards antenna resonating element  68 ′ formed from segment  220  of peripheral conductive housing structures  12 W. As described above, to maximize the antenna efficiency of antenna  40 ′, it may be desirable to hold conductive structures closest to antenna  40 ′ (e.g., closest to antenna resonating element  68 ′) at a ground potential. In the case of the ground traces on substrate  72 , these ground traces are grounded at second end  72 - 2  (e.g., at connector  123 ), and as such, ground traces that extend towards antenna  40 ′ at second end  72 - 2  may float away from a ground potential and undesirably impact the antenna efficiency of antenna  40 ′. 
     To mitigate these issues, device  10  may include conductive structure  228  (e.g., at one or more locations ‘x’) at first end  72 - 1 . Conductive structure  228  may couple (e.g., electrically connect) the ground traces or other ground structures of substrate  72  to ground structures  216 , thereby holding these ground structures at a ground potential at first end  72 - 1  and consequently improving the antenna efficiency of antenna  40 ′. If desired, conductive structure  228  may be disposed at and/or along an edge of ground structures  216  defining slot  150 . If desired, ground traces on substrate  72  may similarly terminate at or near this edge of ground structures  216  such that ground structures on substrate  72  do not extend substantially into slot  150  towards antenna resonating element  68 ′. 
     Conductive structure  228  may be formed from any suitable conductive and/or attachment structures such as conductive adhesive, a conductive foam, clips, screws, pins, springs, brackets, solder, welds, other conductive and/or attachment structures, or combinations of two or more of these structures. In the example of  FIG.  9   , conductive structure  228  is shown to be interposed between a lower surface of substrate  72  (surface  124  in  FIG.  7   ) and an opposing surface of ground structures  216 . This is merely illustrative. If desired, conductive structure  228  may disposed at any suitable location to ground the ground traces of substrate  72  at or near first end  72 - 1 . 
     To provide improved millimeter/centimeter wave wireless communications capabilities, it may be desirable to include multiple dual-polarization antenna elements (e.g., antennas in antenna module  120 ). However, this may also require that substrate  72  include a large number of transmission lines and isolation structures between transmission lines. Consequently, substrate  72  may be bulkier, stiffer, and larger, thereby making assembling substrate  72  in a satisfactory manner more difficult. To facilitate the assembly of substrate  72  into device  10 , substrate  72  may include an opening or slot  226 , which improves the flexibility of substrate  72 . 
     As shown in  FIG.  9   , slot  226  may extend completely through substrate  72 , and may be an elongated slot extending along the elongated length dimension of substrate  72  (e.g., extending along transmission lines  88 ). In particular, slot  226  may extend between first end portion  72 - 1  and second end portion  72 - 1 . In configurations where substrate  72  has a bend and/or is curved, slot  226  may have a curvature following the bend or curvature of substrate  72 . If desired, slot  226  may be centered about one or more (curved) central axes of substrate  72  such that a number of signal paths (e.g., transmission lines  88 ) on either side (e.g., left and right opposing sides) of slot may be substantially the same. In other words, transmission lines  88  may split at a first end of slot  226 , run along either side of slot  226  and meet at second opposing end of slot  226 . These examples are merely illustrative. If desired, one or more slots with any suitable configurations (e.g., shapes, sizes, etc.) may be formed in substrate  72  to improve the assembly of substrate  72  in device  10 . 
     However, if care is not taken, the existence of slot  226  may adversely impact antenna performance (e.g., of antenna  40 ′, of antennas in module  120 , etc.). In particular, because of the close proximity of antenna  40 ′ and other antenna elements, slot  226  may unintentionally and undesirably resonate due to coupling with one or more nearby antenna elements (e.g., with antenna  40 ′, antenna  40 H, antenna  40 L, etc.). 
     To mitigate these issues, slot  226  in substrate  72  may be provided with additional isolation and/or conductive structures.  FIG.  10    is a top down view of the portion of substrate  72  having slot  226 . As shown in  FIG.  10   , substrate  72  may include transmission lines  88 - 1  to  88 - 8 . Transmission lines  88 - 1  to  88 - 4  may run along a left edge of slot  226 , while transmission lines  88 - 5  to  88 - 8  may run alone the right edge of slot  226 . This is merely illustrative. 
     Substrate  72  may include a plurality of conductive vias  228  (sometimes referred to herein as a fence of conductive vias) that laterally surround each of transmission lines  88  on substrate  72 . Conductive vias  228  may extend in the Z direction (at least partially or completely) through substrate  72 . As an example, each conductive via  228  may connect and be shorted to one or more ground traces in substrate  72  to hold the ground traces at the same ground or reference potential as the ground traces. If desired, each conductive via  228  may be shorted to other traces in substrate  72 . In particular, these conductive vias  228  may be disposed between two adjacent transmission lines to isolate the two transmission lines from each other. As an example, a first set or fence of conductive vias  228 - 1  may be disposed between transmission lines  88 - 1  and  88 - 2 , a second set or fence of conductive vias  228 - 2  may be disposed between transmission lines  88 - 2  and  88 - 3 , and a third set or fence of conductive vias  228 - 3  may be disposed between transmission lines  88 - 3  and  88 - 4 . In a similar manner, sets or fences of conductive vias  228 - 4 ,  228 - 5 , and  228 - 6  may be disposed between corresponding adjacent pairs of transmission lines from transmission lines  88 - 5 ,  88 - 6 ,  88 - 7 , and  88 - 8 . 
     Conductive vias  228  may be separated form one or more adjacent conductive vias in the same fence of conductive vias by a relatively short distance so as to effectively appear as a solid conductive wall to radio-frequency signals conveyed through transmission lines  88  and/or to radio-frequency signals at the frequency of operation of antennas  40 H and  40 L (e.g., the conductive vias may be separated by one-eighth the shortest effective wavelength of these radio-frequency signals, one-tenth the shortest effective wavelength, one-twelfth the shortest effective wavelength, one-fifteenth the shortest effective wavelength, less than one-eighth the shortest effective wavelength, etc.). 
     If desired, each fence of conductive vias  228  may run along the length of transmission lines  88  (e.g., past the portion of substrate  72  shown in  FIG.  10   , to end portion  72 - 1  and/or to end portion  7 - 2  in  FIG.  9   ). If desired, there may be gaps or along the length of each of the fences of vias  228  (e.g., some portions of substrate  72  may lack conductive vias  228 ). If desired, adjacent vias in the same fence or in difference fences may be separated from each other by two or more different distances. These examples are merely illustrative. If desired, the fences of vias  228  may follow any desired lateral outline (e.g., the fences of conductive vias  228  may follow any desired straight and/or curved paths, with or without discontinuities). 
     As described above, if care is not taken, slot  226  in substrate  72  may undesirably resonate due to coupling from the antenna elements of antenna  40 ′ in  FIG.  9    (e.g., at a resonant frequency associated with signal frequencies at which the slot length is approximately equal to half of the effective wavelength of operation). In particular, substrate  72  may include conductive structures (e.g., conductive traces such as ground traces, signal traces, and other traces, vias, and/or other conductive structures). These conductive structures in substrate  72  may surround and define edges of slot  226  (e.g., define a dimension of slot  226  such as a conductive perimeter of slot  226 , a conductive slot length of elongated slot  226 , etc.). The dimension of slot  226  as defined by these conductive structures in substrate  72  may be conducive to unwanted resonance due to coupling from some neighboring antenna elements (e.g., antenna elements of antenna  40 ′). 
     To mitigate these issues, one or more conductive structures  232  may overlap slot  226  and may be coupled to the conductive structures in substrate  72  on opposing sides of slot  226 . Each conductive structure  232  may electrically connect (e.g., short) first conductive structures in substrate  72  on one side of slot  226  to second conductive structures in substrate  72  on the other opposing side of slot  226 . As such, one or more conductive structures  232  may provide one or more corresponding conductive paths bridging elongated slot  226  across its width, thereby effectively altering the dimensions of slot  226  (e.g., shortening the effective length of slot  226  or forming one or more slots having shorter lengths than slot  226  within slot  226 ). In other words, without conductive structures  232 , slot  226  may have a conductive perimeter fully defined by the conductive structures in substrate  72 , but with conductive structures  232 , slot  226  may be (electrically) separated or divided into one or more smaller (e.g., shorter) slots each having a conductive perimeter defined by both the conductive structures in substrate  72  and conductive structure  232 . 
     As such, conductive structures  232  may effectively divide slot  226  into (e.g. may define or form) one or more shorter-length slots each having conductive perimeters and lengths that do not exhibit resonance at or near the frequencies of operation of antenna  40 ′ (e.g., at non-millimeter/centimeter wave frequencies). As an example, a first conductive structure  232  may define an upper end of the shorter slot, a second conductive structure  232  may define a lower end of the shorter slot, and corresponding conductive structures in substrate  72  on opposing sides of the shorter slot may define the left and right edges of the shorter slot. This is merely illustrative. If desired, one of the upper or lower ends of the shorter slot may still be defined by corresponding conductive structures  72  instead of conductive structure  232 . 
     As an example, conductive structures  232  may be disposed on a lower surface of substrate  72  (surface  124  in  FIG.  7   ) and under slot  226 . If desired, conductive structure  232  may be coupled to (e.g., shorted to) conductive structures in substrate  72  that define opposing edges of slot  226  (e.g., ground traces, vias, or other conductive traces) at the lower surface of substrate  72 . If desired, conductive structures  232  may be coupled to and shorted to ground structures such as ground structures  216 . Conductive structures  232  may be formed from one or more sheets of conductive tape or other thin and/or flexible conductive structures that do not negate the flexibility of substrate  72  imparted by slot  226 . While three separate conductive structures  232  are shown in  FIG.  10   , this is merely illustrative. Any number of conductive structures of any suitable types and in any suitable configuration may be used to alter the effective length of slot  226  while substantially preserving the flexibility of substrate  72  imparted by the existence of slot  226 . As an example, conductive structures  232  may be disposed on an upper surface of substrate  72  (surface  122  in  FIG.  7   ) and over slot  226 , and/or within slot  226 . As other examples, conductive structures  232  may include conductive adhesive, conductive foam, conductive brackets, conductive clips, sheet metal, conductive traces, solder, welds, or other conductive structures. 
     While the shorter slots (e.g., formed from the division of slot  226  by conductive structures  232 ) do not exhibit resonance at the frequencies of operation of antenna  40 ′, the shorter slot lengths may undesirably exhibit resonance at higher frequencies if coupled with elements for antennas  40 H and  40 L (e.g., transmission lines  88 , resonating elements  68 , etc.). To mitigate these issues, a fence of conductive vias  230  may surround slot  226 , and may isolate slot  226  and shield slot  226  from any undesired coupling to slot  226  from elements of antennas  40 H and  40 L. In particular, as shown in the example of  FIG.  10   , the fence of conductive vias  230  may run around the top end  225  of slot  226  and may run along the left and right sides of slot  226 . If desired, the fence of conductive vias  230  may also separate slot  226  from adjacent transmission lines (e.g., transmission lines  88 - 4  and  88 - 5 ). 
     If desired, the fence of conductive vias may terminate on the left and right sides of slot  226  before reaching bottom end  227  of slot  226 . In particular, end  225  may be closer to antenna resonating elements for antennas  40 H and  40 L than end  227  and may therefore necessitate isolation. Alternatively, if desired, the fence of conductive vias may also run around end  227 . In general, the fence of conductive vias  230  may have gaps or discontinuities where shielding or isolation of slot  226  is not essential. In other words, the fence of conductive vias  230  may laterally surround (completely or partially) slot  226  in substrate  72 . 
     Conductive vias  230  may extend in the Z direction (at least partially or completely) through substrate  72 . As an example, each conductive via  230  may connect and be shorted to one or more ground traces in substrate  72  to hold them at the same ground or reference potential as the ground traces. If desired, each conductive  228  via may be shorted to other traces in substrate  72 . Conductive vias  230  may be separated form one or more adjacent conductive vias in the same fence of conductive vias by a relatively short distance so as to effectively appear as a solid conductive wall to radio-frequency signals conveyed through transmission lines  88  and/or to radio-frequency signals at the frequency of operation of antennas  40 H and  40 L (e.g., the conductive vias may be separated by one-eighth the shortest effective wavelength of these radio-frequency signals, one-tenth the shortest effective wavelength, one-twelfth the shortest effective wavelength, one-fifteenth the shortest effective wavelength, less than one-eighth the shortest effective wavelength, etc.). 
     These examples are merely illustrative. If desired, the fence of vias  230  may follow any desired lateral outline (e.g., the fences of conductive vias  230  may follow any desired straight and/or curved paths, with or without discontinuities). 
       FIG.  11    is a cross-sectional view of substrate  72  coupled to ground structures  216  and antenna module  120  for device  10 . As shown in  FIG.  11    substrate  72  may include stacked dielectric layers  240 . Dielectric layers  240  may include polyimide, ceramic, liquid crystal polymer, plastic, and/or any other desired dielectric materials. Conductive traces such as conductive traces  242  may be formed on a top surface of substrate  72 . Conductive traces  242  may form transmission lines for antennas  40 H and  40 L and may therefore sometimes be referred to herein as signal traces  242 . Conductive traces such as conductive traces  244  may be pattern on an opposing bottom surface of substrate  72 . Conductive traces  244  may be held at a ground potential and may therefore sometimes be referred to herein as ground traces  244 . 
     Ground traces  244  may be shorted to additional ground traces within substrate  72  and/or on the top surface of substrate  72  using conducive vias that extend through substrate  72  (e.g., conductive vias  230  and  228 ). As described in connection with  FIG.  10   , fences of conductive vias  228  may separate adjacent transmission lines (e.g., adjacent signal traces  242 ). Fences of conductive vias  230  may laterally surround slot  226  (as also shown in  FIG.  11   ) and may separate slot  226  from transmission lines  88 . Ground traces  244  may form part of the antenna ground for antennas in device  10 . Ground traces  244  may be coupled to a system ground in device  10  such as ground structures  216  (e.g., using solder, welds, conductive adhesive, conductive tape, conductive brackets, conductive pins, conductive screws, conductive clips, combinations of these, etc.). As an example, conductive structures  228  may connected ground traces  244  to ground structures  216  to hold ground traces  244  at end  72 - 1  of substrate  72  at a ground potential. As another example, conductive structures  232  under slot  226  may connect ground traces adjacent to slot  226  to ground structures  216 . 
     The example of  FIG.  11    in which conductive traces  242  are formed on the top surface and ground traces  244  are formed on the bottom surface of substrate  72  is merely illustrative. If desired, one or more dielectric layers  240  may be layered over conductive traces  242  and/or one or more dielectric layers  240  may be layered under ground traces  244 . 
     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.