PATENT DOCUMENT

Publication Number: US-12107328-B2
Application Number: US-202217828859-A
Country: US
Kind Code: B2

Title: Electronic devices with interconnected ground structures

Abstract:
An electronic device may include wireless circuitry having one or more antennas. An antenna ground for an antenna may be formed from two separate conductive ground structures coupled to each other via a conductive interconnect structure. A slot element may be formed in one of the conductive ground structures to reject signals at one or more victim frequencies resulting from spurious signals generated by a non-ohmic contact formed between the conductive interconnect structure and the one of the conductive ground structures. The conductive interconnect structure may overlap and excite the slot element, which serves as an ineffective radiator at the one or more victim frequencies.

Claims:
What is claimed is: 
     
       1. An antenna comprising:
 a first antenna ground structure; 
 a second antenna ground structure separated from the first antenna ground structure by a non-conductive gap; and 
 a conductive interconnect structure that extends across the non-conductive gap and couples the first antenna ground structure to the second antenna ground structure, the first antenna ground structure having a slot element and the conductive interconnect structure being coupled across the slot element, wherein the conductive interconnect structure provides a shorting path between the first antenna ground structure and the second antenna ground structure. 
 
     
     
       2. The antenna defined in  claim 1 , wherein the conductive interconnect structure is electrically shorted to the first antenna ground structure on opposing first and second sides of the slot element. 
     
     
       3. The antenna defined in  claim 2 , wherein the slot element has peripheral sides defined by the first antenna ground structure. 
     
     
       4. The antenna defined in  claim 3 , wherein the slot element is configured to be excited by the conductive interconnect structure to cause a standing wave between the peripheral sides of the slot element defined by the first antenna ground structure. 
     
     
       5. The antenna defined in  claim 1 , wherein the conductive interconnect structure forms non-ohmic contacts with the first antenna ground structure on opposing first and second sides of the slot element. 
     
     
       6. The antenna defined in  claim 5 , wherein the conductive interconnect structure comprises a conductive tape, a conductive adhesive layer, or a conductive foam. 
     
     
       7. The antenna defined in  claim 1  further comprising:
 an antenna resonating element; and 
 an antenna feed having a first antenna feed terminal coupled to the antenna resonating element and a second antenna feed terminal coupled to the second antenna ground structure. 
 
     
     
       8. The antenna defined in  claim 1 , wherein the first antenna ground structure is formed from a first conductive structure in a display assembly and the second antenna ground structure is formed from a second conductive structure in the display assembly. 
     
     
       9. An electronic device comprising:
 a first antenna ground structure; 
 a second antenna ground structure; 
 an interconnect structure electrically connecting the first antenna ground structure to the second antenna ground structure and configured to generate radio-frequency signals at a victim frequency; and 
 a victim frequency rejection slot element in the first antenna ground structure configured to be excited by the interconnect structure and to exhibit a resonance peak at an additional frequency that is different from the victim frequency, wherein the first antenna ground structure has first and second portions that form first and second opposing edges of the victim frequency rejection slot element. 
 
     
     
       10. The electronic device defined in  claim 9 , wherein the first antenna ground structure has third and fourth portions that form third and fourth opposing edges of the victim frequency rejection slot element. 
     
     
       11. The electronic device defined in  claim 9 , further comprising:
 an additional victim frequency rejection slot element in the second antenna ground structure. 
 
     
     
       12. The electronic device defined in  claim 9  further comprising:
 wireless circuitry having a portion subject to interference by the radio-frequency signals at the victim frequency. 
 
     
     
       13. The electronic device defined in  claim 12 , wherein the wireless circuitry has an additional portion configured to convey radio-frequency signals at an aggressor frequency and the interconnect structure is configured to generate the radio-frequency signals at the victim frequency based on the radio-frequency signals at the aggressor frequency. 
     
     
       14. The electronic device defined in  claim 13 , wherein the interconnect structure generates the radio-frequency signals at the victim frequency based on a non-ohmic contact with the first antenna ground structure. 
     
     
       15. The electronic device defined in  claim 13 , wherein the victim frequency is a harmonic frequency of the aggressor frequency or a frequency associated with an intermodulation product based on the aggressor frequency. 
     
     
       16. The electronic device defined in  claim 9  further comprising:
 a display having a display layer that forms display pixel circuitry and a display cover layer overlapping the display layer, wherein a first conductive structure overlapping the display forms the first antenna ground structure and a second conductive structure overlapping the display cover layer forms the second antenna ground structure. 
 
     
     
       17. The electronic device defined in  claim 16 , wherein the first conductive structure extends across an active area of the display and the second conductive structure runs along a periphery of the display. 
     
     
       18. An electronic device comprising:
 wireless circuitry configured to convey radio-frequency signals at a frequency, the wireless circuitry having an antenna ground that includes:
 a first conductive ground structure, 
 a second conductive ground structure separated from the first conductive ground structure by a gap, 
 a grounding interconnect structure, and 
 a dielectric-filled slot in the first conductive ground structure, wherein the dielectric-filled slot is a closed slot surrounded by the first conductive ground structure, and the grounding interconnect structure extends across the gap and across the dielectric-filed slot, is coupled to the first conductive ground structure on opposing sides of the closed slot, and is coupled to the second conductive ground structure. 
 
 
     
     
       19. The electronic device defined in  claim 18 , wherein the wireless circuitry includes a radio-frequency transmission line path having a ground conductor coupled to the grounding interconnect structure using an antenna feed terminal coupled to the antenna ground, and the ground conductor conveys the radio-frequency signals at the frequency to the grounding interconnect structure. 
     
     
       20. The electronic device defined in  claim 18 , wherein the frequency is in a wireless local area network (WLAN) frequency band or a wireless personal area network (WPAN) frequency band.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications capabilities. 
     Electronic devices such as portable computers and cellular telephones are often provided with wireless communications capabilities. To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to implement wireless communications circuitry such as antenna components using compact structures. At the same time, there is a desire for wireless devices to cover a growing number of communications bands. 
     Antenna components, especially in compact devices, often include multiple ground structures that are interconnected. Improperly interconnected ground structures have the potential to interfere with the operation of wireless components in a wireless device. As such, care must be taken when implementing antenna components such as ground structures in an electronic device. 
     SUMMARY 
     An electronic device may include wireless circuitry having one or more antennas. Multiple separate conductive ground structures may be coupled to each other via a conductive interconnect structure. The collective interconnected structures may form an antenna ground for one or more of the antennas. In some illustrative configurations, the conductive interconnect structure may form a non-ohmic contact with the ground structures, thereby introducing a spurious signal source. The spurious signal source may cause aggressor portions of the wireless circuitry to undesirably influence victim portions of the wireless circuitry. As an example, the spurious signal source may generate at a harmonic victim frequency based on radio-frequency signals at a fundamental aggressor frequency. 
     One or more of the conductive ground structures may include a slot element configured to reject signals at one or more victim frequencies resulting from the spurious signal source. The conductive interconnect structure may overlap and excite the slot element, which serves as an ineffective radiator at the one or more victim frequencies thereby reducing the impact of signals at the one or more victim frequencies on the victim portions of the wireless circuitry. With the implementation of the slot element, the conductive ground structure may exhibit localized standing waves around the slot element instead of across the entirety of the conductive ground structure. 
     If desired, the multiple separate conductive ground structures may be formed from conductive portions of a display assembly such as a display backplate and a display (cover layer) frame structure. 
    
    
     
       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 schematic diagram of illustrative ground structures in accordance with some embodiments. 
         FIG.  5    is a schematic diagram of an illustrative spurious signal source in wireless circuitry in accordance with some embodiments. 
         FIG.  6    is a plan view of two illustrative portions of ground structures, one of which has a slot element for rejecting signals at one or more victim frequencies, in accordance with some embodiments. 
         FIG.  7    is a plan view of illustrative interior display module structures having a slot element in a ground structure for rejecting signals at one or more victim frequencies in accordance with some embodiments. 
         FIG.  8    is a cross-sectional view of an illustrative portion of the display module structures in  FIG.  7    in accordance with some embodiments. 
         FIG.  9    is a cross-sectional view of an illustrative electronic device portion having multiple ground structures that may implement a slot element for rejecting signals at one or more victim frequencies in accordance with some embodiments. 
         FIG.  10    is a plot showing how a slot element coupled to an interconnecting element between ground structures reduces peak standing wave current amplitude at an illustrative victim frequency in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG.  1    may be provided with wireless circuitry that includes antennas. The antennas may be used to transmit and/or receive wireless radio-frequency signals. 
     Device  10  may be a portable electronic device or other suitable electronic device. For example, device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, headset device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, a wireless access point, a wireless base station, an electronic device incorporated into a kiosk, building, or vehicle, or other suitable electronic equipment. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may be mounted on the front face of device  10 . Display  14  may be a touch screen that incorporates capacitive touch electrodes or may be insensitive to touch. The rear face of housing  12  (i.e., the face of device  10  opposing the front face of device  10 ) may have a substantially planar housing wall such as rear housing wall  12 R (e.g., a planar housing wall). Rear housing wall  12 R may have slots that pass entirely through the rear housing wall and that therefore separate portions of housing  12  from each other. Rear housing wall  12 R may include conductive portions and/or dielectric portions. If desired, rear housing wall  12 R may include a planar metal layer covered by a thin layer or coating of dielectric such as glass, plastic, sapphire, or ceramic (e.g., a dielectric cover layer). Housing  12  may also have shallow grooves that do not pass entirely through housing  12 . The slots and grooves may be filled with plastic or other dielectric materials. If desired, portions of housing  12  that have been separated from each other (e.g., by a through slot) may be joined by internal conductive structures (e.g., sheet metal or other metal members that bridge the slot). 
     Housing  12  may include peripheral housing structures such as peripheral structures  12 W. Conductive portions of peripheral structures  12 W and conductive portions of rear housing wall  12 R may sometimes be referred to herein collectively as conductive structures of housing  12 . Peripheral structures  12 W may run around the periphery of device  10  and display  14 . In configurations in which device  10  and display  14  have a rectangular shape with four edges, peripheral structures  12 W may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges and that extend from rear housing wall  12 R to the front face of device  10  (as an example). In other words, device  10  may have a length (e.g., measured parallel to the Y-axis), a width that is less than the length (e.g., measured parallel to the X-axis), and a height (e.g., measured parallel to the Z-axis) that is less than the width. Peripheral structures  12 W or part of peripheral structures  12 W may serve as a bezel for display  14  (e.g., a cosmetic trim that surrounds all four sides of display  14  and/or that helps hold display  14  to device  10 ) if desired. Peripheral structures  12 W may, if desired, form sidewall structures for device  10  (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.). 
     Peripheral structures  12 W may be formed of a conductive material such as metal and may therefore sometimes be referred to as peripheral conductive housing structures, conductive housing structures, peripheral metal structures, peripheral conductive sidewalls, peripheral conductive sidewall structures, conductive housing sidewalls, peripheral conductive housing sidewalls, sidewalls, sidewall structures, or a peripheral conductive housing member (as examples). Peripheral conductive housing structures  12 W may be formed from a metal such as stainless steel, aluminum, alloys, or other suitable materials. One, two, or more than two separate structures may be used in forming peripheral conductive housing structures  12 W. 
     It is not necessary for peripheral conductive housing structures  12 W to have a uniform cross-section. For example, the top portion of peripheral conductive housing structures  12 W may, if desired, have an inwardly protruding ledge that helps hold display  14  in place. The bottom portion of peripheral conductive housing structures  12 W may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). Peripheral conductive housing structures  12 W may have substantially straight vertical sidewalls, may have sidewalls that are curved, or may have other suitable shapes. In some configurations (e.g., when peripheral conductive housing structures  12 W serve as a bezel for display  14 ), peripheral conductive housing structures  12 W may run around the lip of housing  12  (i.e., peripheral conductive housing structures  12 W may cover only the edge of housing  12  that surrounds display  14  and not the rest of the sidewalls of housing  12 ). 
     Rear housing wall  12 R may lie in a plane that is parallel to display  14 . In configurations for device  10  in which some or all of rear housing wall  12 R is formed from metal, it may be desirable to form parts of peripheral conductive housing structures  12 W as integral portions of the housing structures forming rear housing wall  12 R. For example, rear housing wall  12 R of device  10  may include a planar metal structure and portions of peripheral conductive housing structures  12 W on the sides of housing  12  may be formed as flat or curved vertically extending integral metal portions of the planar metal structure (e.g., housing structures  12 R and  12 W may be formed from a continuous piece of metal in a unibody configuration). Housing structures such as these may, if desired, be machined from a block of metal and/or may include multiple metal pieces that are assembled together to form housing  12 . Rear housing wall  12 R may have one or more, two or more, or three or more portions. Peripheral conductive housing structures  12 W and/or conductive portions of rear housing wall  12 R may form one or more exterior surfaces of device  10  (e.g., surfaces that are visible to a user of device  10 ) and/or may be implemented using internal structures that do not form exterior surfaces of device  10  (e.g., conductive housing structures that are not visible to a user of device  10  such as conductive structures that are covered with layers such as thin cosmetic layers, protective coatings, and/or other coating/cover layers that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide peripheral conductive housing structures  12 W and/or conductive portions of rear housing wall  12 R from view of the user). 
     Display  14  may have an array of pixels that form an active area AA that displays images for a user of device  10 . For example, active area AA may include an array of display pixels. The array of pixels may be formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels or other light-emitting diode pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. If desired, active area AA may include touch sensors such as touch sensor capacitive electrodes, force sensors, or other sensors for gathering a user input. 
     Display  14  may have an inactive border region that runs along one or more of the edges of active area AA. Inactive area IA of display  14  may be free of pixels for displaying images and may overlap circuitry and other internal device structures in housing  12 . To block these structures from view by a user of device  10 , the underside of the display cover layer or other layers in display  14  that overlap inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color. Inactive area IA may include a recessed region such as notch  24  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  24  of inactive area IA). Notch  24  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  24  or a microphone port. Openings may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, etc.) and/or audio ports for audio components such as a speaker and/or a microphone if desired. 
     Display  14  may include conductive structures such as an array of capacitive electrodes for a touch sensor, conductive lines for addressing pixels, driver circuits, etc. Housing  12  may include internal conductive structures such as metal frame members and a planar conductive housing member (sometimes referred to as a conductive support plate or backplate) that spans the walls of housing  12  (e.g., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of peripheral conductive housing structures  12 W). The conductive support plate may form an exterior rear surface of device  10  or may be covered by a dielectric cover layer such as a thin cosmetic layer, protective coating, and/or other coatings that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide the conductive support plate from view of the user (e.g., the conductive support plate may form part of rear housing wall  12 R). Device  10  may also include conductive structures such as printed circuit boards, components mounted on printed circuit boards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device  10 , may extend under active area AA of display  14 , for example. 
     In regions  22  and  20 , openings may be formed within the conductive structures of device  10  (e.g., between peripheral conductive housing structures  12 W and opposing conductive ground structures such as conductive portions of rear housing wall  12 R, conductive traces on a printed circuit board, conductive electrical components in display  14 , etc.). These openings, which may sometimes be referred to as gaps, may be filled with air, plastic, and/or other dielectrics and may be used in forming slot antenna resonating elements for one or more antennas in device  10 , if desired. 
     Conductive housing structures and other conductive structures in device  10  may serve as a ground plane for the antennas in device  10 . The openings in regions  22  and  20  may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element from the ground plane, may contribute to the performance of a parasitic antenna resonating element, or may otherwise serve as part of antenna structures formed in regions  22  and  20 . If desired, the ground plane that is under active area AA of display  14  and/or other metal structures in device  10  may have portions that extend into parts of the ends of device  10  (e.g., the ground may extend towards the dielectric-filled openings in regions  22  and  20 ), thereby narrowing the slots in regions  22  and  20 . Region  22  may sometimes be referred to herein as lower region  22  or lower end  22  of device  10 . Region  20  may sometimes be referred to herein as upper region  20  or upper end  20  of device  10 . 
     In general, device  10  may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device  10  may be located at opposing first and second ends of an elongated device housing (e.g., at lower region  22  and/or upper region  20  of device  10  of  FIG.  1   ), along one or more edges of a device housing, in the center of a device housing, in other suitable locations, or in one or more of these locations. The arrangement of  FIG.  1    is merely illustrative. 
     Portions of peripheral conductive housing structures  12 W may be provided with peripheral gap structures. For example, peripheral conductive housing structures  12 W may be provided with one or more dielectric-filled gaps such as gaps  18 , as shown in  FIG.  1   . The gaps in peripheral conductive housing structures  12 W may be filled with dielectric such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. Gaps  18  may divide peripheral conductive housing structures  12 W into one or more peripheral conductive segments. The conductive segments that are formed in this way may form parts of antennas in device  10  if desired. Other dielectric openings may be formed in peripheral conductive housing structures  12 W (e.g., dielectric openings other than gaps  18 ) and may serve as dielectric antenna windows for antennas mounted within the interior of device  10 . Antennas within device  10  may be aligned with the dielectric antenna windows for conveying radio-frequency signals through peripheral conductive housing structures  12 W. Antennas within device  10  may also be aligned with inactive area IA of display  14  for conveying radio-frequency signals through display  14 . 
     In a typical scenario, device  10  may have one or more upper antennas and one or more lower antennas. An upper antenna may, for example, be formed in upper region  20  of device  10 . A lower antenna may, for example, be formed in lower region  22  of device  10 . Additional antennas may be formed along the edges of housing  12  extending between regions  20  and  22  if desired. 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  38 . Control circuitry  38  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  38  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, graphics processing units, central processing units (CPUs), etc. Control circuitry  38  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  38  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  38  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  38  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  26 . Input-output circuitry  26  may include input-output devices  28 . Input-output devices  28  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  28  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  26  may include wireless circuitry such as wireless circuitry  34  for wirelessly conveying radio-frequency signals. While control circuitry  38  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  38  (e.g., portions of control circuitry  38  may be implemented on wireless circuitry  34 ). As an example, control circuitry  38  may include baseband processor circuitry or other control components that form a part of wireless circuitry  34 . 
     Wireless circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless circuitry  34  may include radio-frequency transceiver circuitry  36  for handling transmission and/or reception of radio-frequency signals within corresponding frequency bands at radio frequencies (sometimes referred to herein as communications bands or simply as “bands”). The frequency bands handled by radio-frequency transceiver circuitry  36  may include wireless local area network (WLAN) frequency bands (e.g., Wi-Fi® (IEEE 802.11) or other WLAN communications bands) such as a 2.4 GHz WLAN band (e.g., from 2400 to 2480 MHz), a 5 GHz WLAN band (e.g., from 5180 to 5825 MHz), a Wi-Fi® 6E band (e.g., from 5925-7125 MHz), and/or other Wi-Fi® bands (e.g., from 1875-5160 MHz), wireless personal area network (WPAN) frequency bands such as the 2.4 GHz Bluetooth® band or other WPAN communications bands, cellular telephone communications bands such as a cellular low band (LB) (e.g., 600 to 960 MHz), a cellular low-midband (LMB) (e.g., 1400 to 1550 MHz), a cellular midband (MB) (e.g., from 1700 to 2200 MHz), a cellular high band (HB) (e.g., from 2300 to 2700 MHz), a cellular ultra-high band (UHB) (e.g., from 3300 to 5000 MHz, or other cellular communications bands between about 600 MHz and about 5000 MHz), 3G bands, 4G LTE bands, 3GPP 5G New Radio Frequency Range 1 (FR1) bands below 10 GHz, 3GPP 5G New Radio (NR) Frequency Range 2 (FR2) bands between 20 and 60 GHz, other centimeter or millimeter wave frequency bands between 10-300 GHz, near-field communications frequency bands (e.g., at 13.56 MHz), satellite navigation frequency bands such as the Global Positioning System (GPS) L1 band (e.g., at 1575 MHz), L2 band (e.g., at 1228 MHz), L3 band (e.g., at 1381 MHz), L4 band (e.g., at 1380 MHz), and/or L5 band (e.g., at 1176 MHz), a Global Navigation Satellite System (GLONASS) band, a BeiDou Navigation Satellite System (BDS) band, ultra-wideband (UWB) frequency bands that operate under the IEEE 802.15.4 protocol and/or other ultra-wideband communications protocols (e.g., a first UWB communications band at 6.5 GHz and/or a second UWB communications band at 8.0 GHz), communications bands under the family of 3GPP wireless communications standards, communications bands under the IEEE 802.XX family of standards, satellite communications bands such as an L-band, S-band (e.g., from 2-4 GHz), C-band (e.g., from 4-8 GHz), X-band, Ku-band (e.g., from 12-18 GHz), Ka-band (e.g., from 26-40 GHz), etc., industrial, scientific, and medical (ISM) bands such as an ISM band between around 900 MHz and 950 MHz or other ISM bands below or above 1 GHz, one or more unlicensed bands, one or more bands reserved for emergency and/or public services, and/or any other desired frequency bands of interest. Wireless circuitry  34  may also be used to perform spatial ranging operations if desired. 
     Radio-frequency transceiver circuitry  36  may include respective transceivers (e.g., transceiver integrated circuits or chips) that handle each of these frequency bands or any desired number of transceivers that handle two or more of these frequency bands. In scenarios where different transceivers are coupled to the same antenna, filter circuitry (e.g., duplexer circuitry, diplexer circuitry, low pass filter circuitry, high pass filter circuitry, band pass filter circuitry, band stop filter circuitry, etc.), switching circuitry, multiplexing circuitry, or any other desired circuitry may be used to isolate radio-frequency signals conveyed by each transceiver over the same antenna (e.g., filtering circuitry or multiplexing circuitry may be interposed on a radio-frequency transmission line shared by the transceivers). Radio-frequency transceiver circuitry  36  may include one or more integrated circuits (chips), integrated circuit packages (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.), power amplifier circuitry, up-conversion circuitry, down-conversion circuitry, low-noise input amplifiers, passive radio-frequency components, switching circuitry, transmission line structures, and other circuitry for handling radio-frequency signals and/or for converting signals between radio-frequencies, intermediate frequencies, and/or baseband frequencies. 
     In general, radio-frequency transceiver circuitry  36  may cover (handle) any desired frequency bands of interest. As shown in  FIG.  2   , wireless circuitry  34  may include antennas  40 . Radio-frequency transceiver circuitry  36  may convey radio-frequency signals using one or more antennas  40  (e.g., antennas  40  may convey the radio-frequency signals for the transceiver circuitry). The term “convey radio-frequency signals” as used herein means the transmission and/or reception of the radio-frequency signals (e.g., for performing unidirectional and/or bidirectional wireless communications with external wireless communications equipment). Antennas  40  may transmit the radio-frequency signals by radiating the radio-frequency signals into free space (or to free space 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. 
     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, waveguide structures, monopole antenna structures, dipole antenna structures, helical antenna structures, Yagi (Yagi-Uda) antenna structures, hybrids of these designs, etc. If desired, 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. Two or more antennas  40  may be arranged in a phased antenna array if desired (e.g., for conveying centimeter and/or millimeter wave signals within a signal beam formed in a desired beam pointing direction that may be steered/adjusted over time). Different types of antennas may be used for different bands and combinations of bands. 
       FIG.  3    is a schematic diagram showing how a given antenna  40  may be fed by radio-frequency transceiver circuitry  36 . As shown in  FIG.  3   , antenna  40  may have a corresponding antenna feed  50 . Antenna  40  may include an antenna resonating (radiating) element and an antenna ground. Antenna feed  50  may include a positive antenna feed terminal  52  coupled to the antenna resonating element and a ground antenna feed terminal  44  coupled to the antenna ground. 
     Radio-frequency transceiver circuitry  36  may be coupled to antenna feed  50  using a radio-frequency transmission line path  42  (sometimes referred to herein as transmission line path  42 ). Transmission line path  42  may include a signal conductor such as signal conductor  46  (e.g., a positive signal conductor). Transmission line path  42  may include a ground conductor such as ground conductor  48 . Ground conductor  48  may be coupled to ground antenna feed terminal  44  of antenna feed  50 . Signal conductor  46  may be coupled to positive antenna feed terminal  52  of antenna feed  50 . 
     Transmission line path  42  may include one or more radio-frequency transmission lines. The radio-frequency transmission line(s) in transmission line path  42  may include stripline transmission lines (sometimes referred to herein simply as striplines), coaxial cables, coaxial probes realized by metalized vias, microstrip transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, combinations of these, etc. Multiple types of radio-frequency transmission line may be used to form transmission line path  42 . Filter circuitry, switching circuitry, impedance matching circuitry, phase shifter circuitry, amplifier circuitry, and/or other circuitry may be interposed on transmission line path  42 , if desired. One or more antenna tuning components for adjusting the frequency response of antenna  40  in one or more bands may be interposed on transmission line path  42  and/or may be integrated within antenna  40  (e.g., coupled between the antenna ground and the antenna resonating element of antenna  40 , coupled between different portions of the antenna resonating element of antenna  40 , etc.). 
     If desired, one or more of the radio-frequency transmission lines in transmission line path  42  may be integrated into ceramic substrates, rigid printed circuit boards, and/or flexible printed circuits. In one suitable arrangement, the radio-frequency transmission lines 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 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    is a schematic diagram showing how illustrative ground structures may be implemented within device  10 . In particular, to implement an electrical ground for components such as an antenna ground for one or more of antennas  40  in device  10  as described in connection with  FIG.  3   , device  10  may include multiple ground structures  60  (e.g., structures that collectively form part of the antenna ground for one or more of antennas  40  in device  10 ). The multiple ground structures may include a number of discrete individual elements, illustratively shown in  FIG.  4    as a ground structure  62 , a ground structure  64 , and other additional ground structures  66 . Two or more of these individual ground elements may be electrically interconnected using conductive grounding interconnect structures such as interconnect element  68  which connects ground structure  62  to ground structure  64 , as shown in  FIG.  4   . 
     Various elements in device  10  may serve as each of the ground structures  60  for one or more of antennas  40  on device  10 . As examples, ground structures  60  may include conductive portions of a display module or display assembly, one or more metal layers such as a metal layer used to form a rear housing wall and/or an internal support structure for device  10  (e.g., a conductive structural support plate for device  10 ), one or more other conductive portions of housing  12  such as conductive portions of sidewalls  12 W, conductive traces on a printed circuit board, conductive portions of one or more components in device  10 , and/or other conductive elements in device  10 . As further examples, conductive interconnect structures (e.g., conductive interconnect structure  68 ) in ground structures  60  may include conductive adhesive, conductive tape, conductive foam, conductive springs, conductive pins, welds, and/or other conductive elements that serve to electrically (and if desired, physically) interconnect two or more individual ground structures. 
     When multiple pieces of individual antenna ground structures are interconnected, a common and effectively enlarged antenna ground plane may be formed within device  10  for one or more of antennas  40 , thereby enhancing antenna performance. This may be especially advantageous in a compact or small form factor device where a single continuous piece of antenna ground plane may take up valuable space within the device and may not easily conform to the form factor of the device, and is therefore undesirable. The interconnected ground structures may also implement desired antenna ground plane geometries and exhibit other desired characteristics to enhance antenna performance. 
     However, interconnecting individual antenna ground structures can sometimes lead to the introduction of spurious signal sources that can disrupt wireless communications of device  10 . As examples, when using some types of conductive interconnect structures such as conductive adhesive, conductive tape, conductive foam, or other conductive interconnect structures conducive to forming non-ohmic contacts (e.g., contacts that exhibit non-linear voltage-current behavior) to one or more of the interconnected ground structures, these conductive interconnect structures (along with their non-ohmic contacts) may serve as spurious signal sources. In other words, when radio-frequency signals are being conveyed by an antenna  40  containing the interconnected antenna ground structures (e.g., the conductive interconnect structure forms a part of the antenna ground to which the antenna feed for antenna  40  is connected), the non-linear characteristic of the contact may result in the generation of harmonic frequency signals (e.g., signals at one or more harmonics or integer multiples of the frequencies of conveyed signals), and/or intermodulated frequency signals (e.g., signals at one or more non-harmonic frequencies of the conveyed signals resulting from the mixing of two or more conveyed signals), which are collectively referred to herein as spurious signals. As examples, the harmonic frequency signals may include second-order harmonics, third-order harmonics, etc. As examples, the intermodulated frequency signals may include second-order intermodulation products, third-order intermodulation products, fifth-order intermodulation products, etc. 
     As an example, an antenna  40  may have an antenna ground that includes ground structures  62  and  64  and conductive interconnect structure  68  in  FIG.  4   . In scenarios where conductive interconnect structure  68  is connected to ground structure  62  (and/or ground structure  4 ) via a non-ohmic contact, conductive interconnect structure  68  (and its non-ohmic contact) may form a spurious signal source. 
       FIG.  5    is a schematic diagram showing how the generation of spurious signals may impact wireless communications of a wireless device in an illustrative example. As shown in  FIG.  5   , a wireless device such as device  10  may include wireless circuitry  70  (forming a portion of wireless circuitry  34  in  FIG.  2   ) configured to convey radio-frequency signals  72  at a set of frequencies (e.g., in one or more frequency bands). In one illustrative configuration, wireless circuitry  70  may include an antenna and a radio that uses the antenna to convey radio-frequency signals  72 . In particular, radio-frequency signals  72  may be conveyed to an antenna resonating element as well as an antenna ground of the antenna that contains a conductive interconnect structure forming spurious signal source  74  (e.g., in the manner as described above). In other words, while radio-frequency signals  72  are being conveyed into freespace, corresponding radio-frequency signals  72  are also being conveyed to spurious signal source  74  in the antenna ground for wireless circuitry  70  (e.g., via a ground conductor  48  and a corresponding ground feed terminal  44  in  FIG.  3   ). 
     In the example of  FIG.  5   , spurious signal source  74  may generate spurious radio-frequency signals  76  based on received radio-frequency signals  72 . As examples, spurious radio-frequency signals  76  may include one or more harmonic frequency signals or signals at harmonics of the frequencies of radio-frequency signals  72 , one or more intermodulated frequency signals or signals (at non-harmonic frequencies) resulting from the mixing of radio-frequency signals  72  of different frequencies, and/or other spurious signals resulting from other radio-frequency signals. Configurations in which radio-frequency signals  76  include harmonic frequency signals are described herein as an illustrative example. 
     In the example of spurious harmonic radio-frequency signals  76  being generated, one or more of the interconnected ground structures may exhibit standing waves (e.g., a standing wave current and/or voltage distribution) across its entire structure. This can undesirably cause radiation of and further propagate spurious radio-frequency signals  76 . Wireless circuitry  78  in device  10  (forming a portion of wireless circuitry  34  in  FIG.  2   ) different from wireless circuitry portion  70  may perceive (e.g., receive) and be adversely impacted by the propagated spurious harmonic radio-frequency signals  76 . In particular, wireless circuitry  78  may be sensitive to radio-frequency signals at the frequencies of radio-frequency signals  76 . 
     As an example, wireless circuitry  78  may include an antenna and a corresponding radio that uses the antenna to convey radio-frequency signals at a set of frequencies (e.g., in one or more frequency bands), which overlap or include the frequencies of spurious radio-frequency signals  76 . In this scenario, wireless circuitry  78  may receive the radiated spurious signals  76 , which adversely impacts the operation of wireless circuitry  78  (e.g., by increasing the noise floor level, thereby decreasing signal-to-noise ratio, for signals received at wireless circuitry  78 ). 
     Because the conveyance of radio-frequency signals at wireless circuitry  70  ultimately results in spurious signals that impact other wireless circuitry, wireless circuitry  70  may sometimes be referred to as aggressor wireless circuitry  70  (e.g., having one or more aggressor radios and antennas that convey radio-frequency signals that result in the spurious signals). The one or more frequencies of radio-frequency signals  72  resulting in the spurious signals may sometimes be referred to as one or more aggressor frequencies. 
     Because wireless circuitry  78  receives spurious signals resulting from radio-frequency signals from other wireless circuitry, wireless circuitry  78  may sometimes be referred to as victim wireless circuitry  78  (e.g., having one or more victim radios and antennas that receive and process the spurious signals). The one or more frequencies of spurious radio-frequency signals  76  may sometimes be referred to as one or more victim frequencies. In the example of harmonics interference, the one or more aggressor frequencies may be at fundamental frequencies, while the one or more victim frequencies are the harmonics of these fundamental frequencies. 
     In some illustrative configurations described herein as an example, the aggressor wireless circuitry may be associated with a cellular radio and one or more antennas coupled to the cellular radio, and the aggressor frequencies may be one or more frequencies in a cellular low band (e.g., at a frequency of 600 MHz). In this example, the victim wireless circuitry may be associated with a Bluetooth® radio and/or a Wi-Fi® radio and one or more antennas coupled to these radios, and the victim frequencies may be one or more frequencies in a 2.4 GHz Bluetooth® band, in a 2.4 GHz WLAN band, in a 5 GHz WLAN band (e.g., at a frequency of 2.4 GHz, at a frequency of 5.5 GHz, etc.). These frequencies are merely illustrative. In other scenarios, frequencies in one or more other frequency bands may impact or be impacted in a similar manner. 
     The impacts of spurious signals described above in connection with  FIG.  5    are merely illustrative. In general, the existence of one or more spurious signal sources and radiation of corresponding spurious radio-frequency signals may interfere with the operation of any portion of wireless circuitry  34  ( FIG.  1   ) or other components in device  10 . 
     To mitigate the above-mentioned issues resulting from one or more spurious signal sources such as spurious signal source  74 , ground structures  60  may include corresponding slot elements such as slot element  80  coupled to spurious signal source  74 . In other words, a first ground structure, to which a second ground structure is connected via a conductive interconnect structure, may have a slot element  80  formed therein. Slot element  80  may be formed at the (non-ohmic) contact between the conductive interconnect structure and the first ground structure. The conductive interconnect structure may overlap and therefore be coupled to slot element  80 . 
     In such a manner, when radio-frequency signals  72  are received at the second ground structure (e.g., via an antenna feed terminal coupled to the second ground structure) and conveyed to the first ground structure as spurious radio-frequency signals  76  by way of the conductive interconnect structure and the non-ohmic contact serving as spurious signal source  74 , slot element  80  may stop the propagation of the generated spurious radio-frequency signals  76  onto the entire structure of the first ground structure (as standing waves). Instead, spurious radio-frequency signals  76  may be locally coupled onto slot element  80 . 
     In other words, when slot element  80  is excited by the reception of spurious radio-frequency signals  76 , the portion of the first ground structure defining the boundaries of slot element  80  (instead of the entirety of the first ground structure) exhibits standing waves corresponding to spurious radio-frequency signals  76 . Slot element  80  may be configured to reject one or more (victim) frequencies of interest (e.g., may have dimensions that efficiently radiate at frequencies outside of the one or more frequencies of interest). This local excitation of slot element  80  can help reduce the intensity or amplitude of the standing waves at the one or more victim frequencies of spurious signals  76  (relative to scenarios in which standing waves are exhibited across the entirety of a ground structure). 
       FIG.  6    is a top-down view of an illustrative slot element implemented within ground structures  60  (in  FIG.  4   ). In particular,  FIG.  6    shows illustrative portions of the two individual ground structures  62  and  64 , with slot element  80  formed within the illustrated portion of ground structure  62 . 
     Slot element  80  may be a dielectric-filled opening within conductive material (e.g., conductive ground structure  62 ). The opening of slot element  80  may be filled with dielectric material such as air or solid dielectric material. In the configuration of  FIG.  6   , slot element  80  (sometimes referred to herein as slot  80 , opening  80 , notch  80 , interference-mitigating slot element  80 , spurious signal mitigating slot element  80 , or victim frequency rejection structure  80 ) is a closed slot, because portions of ground structure  62  completely surround and enclose slot  80  along lateral peripheral edges. If desired, slot element  80  may be implemented as an open slot formed in ground structure  62  (e.g., by forming slot element  80  such that one of its lateral peripheral edges extends to a peripheral edge of ground structure  62  and the slot element is not completely surrounded by conductive material). 
     To interconnect the two pieces of ground structure  62  and  64  and thereby form a common antenna ground, conductive interconnect structure  68  may extend from ground structure  62  to ground structure  64 . In particular, interconnect structure  68  may electrically and/or physically connect ground structure  62  to ground structure  64 . In the example of  FIG.  6   , interconnect structure  68  may have an elongated shape with one end coupled to (e.g., contacting) ground structure  62  at one or more locations  84  and one or more locations  86  and an opposing end coupled to (e.g., contacting) ground structure  64  at one or more locations  88 . More specifically, interconnect structure  68  may contact ground structure  62  at locations along opposing edges of ground structure  62  defining respective elongated sides of slot element  80 . In such a manner, interconnect structure  68  and its contacts at locations  84  and  86  may be configured to excite, feed, or otherwise cause slot element  80  to exhibit standing waves along its perimeter (e.g., along the perimeter of ground structure portion that defines slot element  80 ) when (spurious) radio-frequency signals are conveyed from interconnect structure  68  onto the portion of ground structure  62  surrounding and defining slot element  80 . 
     In the example of  FIG.  6   , slot element  80  is an elongated rectangular slot element having a length  82  and a width  83 . In general, slot elements tend to exhibit response peaks when the slot perimeter is equal to a target effective wavelength (e.g., where the slot perimeter is equal to two times length  82  plus two times width  83 ). The effective wavelength may be equal to a freespace wavelength multiplied by a constant value that is determined by the dielectric materials in and surrounding slot element  80 . In elongated slot elements where the length is much greater than the width (e.g., the length greater than four times the width, the length greater than eight times the width, the length greater than ten times the width, the length greater than twenty times the width, the length greater than fifty times the width, etc.), the response peaks may be exhibited when the slot length is approximately half of the target wavelength (e.g., is slightly less than half of the target wavelength given a non-zero slot width). 
     To reduce the effectiveness of the radiation of spurious radio-frequency signals at victim frequencies, slot element  80  may be configured to have dimensions that reduce the frequency response at the victim or spurious signal frequencies. In other words, slot element  80  may have dimensions that are not conducive to response peaks at the victim or spurious signal frequencies (e.g., response peaks are generated at frequencies different from the victim frequencies). As such, when interconnect structure  68  (at its contacts to ground structure  62 ) excites slot element  80  at the victim signal frequencies, the amplitudes of standing wave current flowing around the perimeter of slot element  80  (e.g., between contacts at locations  84  and  86 ) at these frequencies may be reduced (relative to scenarios where the dimensions of slot element  80  are designed to effectively radiate at the victim frequencies). This allows slot element  80  to serve as an inefficient radiator at these frequencies and therefore an inefficient propagator of spurious signals. By effectively dissipating signals at these victim frequencies (sometimes referred to herein as rejecting victim frequencies), slot element  80  may therefore reduce the effect of spurious signals (when generated by a spurious signal source) on victim wireless circuitry. 
     In illustrative configurations described herein as examples, slot element  80  may be elongated. In these examples, to reject certain frequencies and their corresponding wavelengths, slot element  80  may have a length less than one-half of the target wavelength, less than one-fourth of the target wavelength, less than one-eighth of the target wavelength, greater than one-tenth of the target wavelength, greater than one-eighth of the target wavelength, greater than one-fourth of the target wavelength, etc. In scenarios where a single victim frequency exists (e.g., victim wireless circuitry is sensitive to only one frequency of spurious signals), the target wavelength may be the wavelength corresponding to the victim frequency (e.g., based on the wave speed or speed of light, accounting for nearby dielectric effects that result in the use of an effective wavelength as described above, etc.). In scenarios where multiple victim frequencies exist (e.g., victim wireless circuitry is sensitive to multiple frequencies of spurious signals), the target wavelength may be the wavelength corresponding to the lowest victim frequency in the multiple victim frequencies. By configuring slot element  80  to reject the lowest of the victim frequencies (e.g., having the longest of wavelengths) in the manner described above, the same configuration for slot element  80  also rejects the higher victim frequencies. 
     In illustrative configurations where victim frequencies are in a 2.4 GHz WPAN band, in a 2.4 GHz WLAN band, and in a 5 GHz WLAN band (e.g., at a frequency of 2.4 GHz, at a frequency of 5.5 GHz, etc.), the length of elongated slot element may be 60 mm (e.g., approximately a length of one-half of the target wavelength associated with a victim frequency of 2.4 GHz), 30 mm (e.g., approximately a length of one-half of the target wavelength associated with a victim frequency of 5.5 GHz), 10 mm (e.g., approximately a length of one-tenth of the target wavelength associated with a victim frequency of 2.4 GHz), or any other length to suitably reject these victim frequencies. It may be desirable to configure the elongated slot element with a length closer to one-eighth to one-tenth of the target wavelength to more effectively reject the set of the victim frequencies. However, given manufacturing, form factor, and/or other constraints, the length of the elongated slot element may be adjusted from this range to more suitably accommodate other constraints. 
     The use of elongated slot element and consequently the consideration of slot length may serve as illustrative and approximate examples for rejecting victim frequencies. If desired, other properties of slot elements such as slot width may also be configured (along with slot length) to provide a slot element for rejecting victim frequencies. 
     Conductive interconnect structure  68  may be coupled across slot element  80  at a location along the elongated edges of ground structure  62  (e.g., at a location along length  82 ). If desired, the location along the length of the slot across which interconnect structure  68  is coupled may be adjusted for impedance control (e.g., to control impedance matching between interconnect structure  68  and slot element  80 ) to enhance rejection of victim frequencies (e.g., decrease frequency response at victim frequencies). 
     Configurations in which interconnect structure  68  is a conductive tape are sometimes described herein as examples. In these configurations, the conductive tape may be physically adhered to ground structure  62  at locations  84  and  86  across slot element  80  and may be physically adhered to ground structure  64  at locations  88 . Simultaneously, these contact locations may also serve as points of electrical (non-ohmic) contact (e.g., provide a low resistance or shorting path between ground structure  62  and interconnect structure  68  and provide a low resistance or shorting path between ground structure  64  and interconnect structure  68 , thereby forming a low resistance or shorting path between ground structures  62  and  64  via interconnect structure  68 ). If desired, the conductive tape may bridge across a lateral gap (absence of conductive material) between ground structure  62  and ground structure  64 . 
     As other examples, interconnect structure  68  may be a conductive adhesive (e.g., a layer of conductive adhesive material deposited over ground structures  62  and  64 ), a conductive foam (e.g., conductive foam interposed or vertically stacked between ground structures  62  and  64 ), other interconnect structures configured to form non-ohmic contacts, and/or a combination of multiple types of interconnect structures. 
     While shown in  FIG.  6    to extend laterally across and to overlap non-overlapping ground structures  62  and  64 , this configuration of interconnect structure  68  in  FIG.  6    is merely illustrative. If desired, the illustrated portions of ground structures  62  and  64  may vertically overlap one another, and interconnect structure  68  may be disposed within the vertical gap between ground structures  62  and  64  and extend between (e.g., be sandwiched between) ground structures  62  and  64 . 
     In general, device  10  may include different individual ground structures oriented relative to one another in different manners and may include interconnect structures connecting the individual ground structures in various orientations. In any of these configurations, one or more slot elements such as slot element  80  may be provided to mitigate the undesired propagation of spurious signals (at one or more victim frequencies). 
     In some illustrative configurations, an antenna feed terminal (e.g., ground antenna feed terminal  44  in  FIG.  3   ) may be coupled to conductive ground structure  64 , and slot element  80  may be formed in a downstream interconnected ground structure  62  (e.g., a ground structure distal to but interconnected via a non-ohmic contact from the ground structure directly connected to the antenna feed terminal). If desired, conductive ground structure  64  may include an analogous slot element (e.g., configured to reject one or more target victim frequencies) instead of or in additional to slot element  80  in ground structure  62 . 
     The configuration of slot element  80  in  FIG.  6    is merely illustrative. In general, slot element  80  may have any desired shape (e.g., with dimensions that impart the above-mentioned rejection of victim frequencies). For example, slot element  80  may have a meandering shape with different segments extending in different directions, may have straight and/or curved edges, etc. 
     While shown in the example of  FIG.  6    to be formed in ground structure  62 , a victim frequency rejection slot element (e.g., configured in the same manner as slot element  80 ) may formed in ground structure  64  in addition to or instead of slot element  80  in ground structure  62 . 
     Conductive elements implementing antenna ground structures  62  and  64  (e.g., one or both of which including a respective victim frequency rejection slot element) may be formed from any desired (grounded) conductive electronic device structures. As one illustrative example, antenna ground structure  62  (and antenna ground structure  64 ) may be formed from conductive structures associated with display  14  ( FIG.  1   ) or generally a display module or display assembly. 
       FIGS.  7  and  8    are illustrative views of conductive structures in a display configured to form the illustrative ground structures and victim frequency rejection structure (e.g., slot element  80 ) as described in connection with  FIGS.  5  and  6   .  FIG.  7    is a plan view of illustrative interior display structures in a display module or display assembly for a display  14  of device  10 . 
     As shown in  FIG.  7   , display module  89  may include a conductive display backplate  90  and a conductive frame structure  92 . Display backplate  90  may be separated from frame structure  92  by a non-conductive gap  94 . To expand the area of the (antenna) ground structures in device  10 , it may be desirable to connect frame structure  92  to backplate  90  to form an expanded ground plane using both structures. As such, a conductive interconnect structure such as interconnect structure  97  (e.g., a conductive tape) may bridge across gap  94  to electrically and physically connect frame structure  92  to backplate  90 . 
     Because interconnect structure  97  may form a non-ohmic contact with frame structure  92  and/or backplate  90 , interconnect structure  97  may cause the generation of spurious signals. Without any victim frequency rejection structures, frame structure  92  (when excited by spurious signals generated by interconnect structure  97 ) may exhibit standing waves (e.g., standing wave current and voltage distributions) across its entire structure around the periphery of display module  89 , thereby radiating at the victim frequencies and degrading the performance of victim wireless circuitry. To provide a victim frequency rejection structure, frame structure  92  may include slot element  80  that overlaps interconnect structure  97 . In such a manner, spurious signals generated by interconnect structure  97  at its non-ohmic contacts may locally excite slot element  80  (e.g., standing waves are locally exhibited in or are concentrated at region  96 ) instead of across the entire structure of frame structure  92 , thereby reducing the amplitude of the standing waves. Furthermore, slot element  80  may have dimensions configured to reject one or more victim frequencies (e.g., to serve as an inefficient radiator at these frequencies by exhibiting reduced or non-peak frequency responses at these frequencies), thereby further reducing the amplitude of the standing waves. 
     In some illustrative scenarios, an additional victim frequency rejection slot element may be formed in a ground structure connected to frame structure  92  in which slot element  80  is formed. In some illustrative scenarios (e.g., considering other device constraints), it may be undesirable to form such a slot element in a display backplate. 
       FIG.  8    is a cross-sectional view of an illustrative portion of the display module structures as viewed along line A-A′ in  FIG.  7   . As shown in  FIG.  8   , display  14  may include display module  89 . Display module  89  may include display layers  98  each implementing one or more of 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  100  that overlaps display module  89 . Display cover layer  100  may include plastic, glass, sapphire, ceramic, and/or any other desired dielectric materials. The active area of display module  89  may emit image light and may receive sensor input (e.g., touch and/or force sensor input) through display cover layer  100 . Display cover layer  100  and display  14  may be mounted to conductive housing structures (structures  12 W in  FIG.  1   ). An inactive area IA of display  14  may surrounded the active area AA of display  14 . 
     Display backplate  90  may serve as a structural support structure supporting display layers  98  and as an electrical ground for components in device  10  (e.g., a reference ground for components implemented by display layers  98 , an antenna ground for wireless communication circuitry  34 , etc.). To effectively serve its functions, display backplate  90  may extend across substantially the entire active area AA of display  14 . 
     Frame structure  92  may run along the periphery (e.g., rectangular periphery as shown in  FIG.  7   ) of display cover layer  100  and serve as a structural support structure, in combination with other intervening structures  102  such as adhesive layers, polymer layers, etc., for display cover layer  100 . If desired, frame structure  92  may have engagement mechanisms that allow display  14  (e.g., the display assembly) to be mounted to and engage corresponding mechanism in the housing (e.g., corresponding engagement mechanisms on peripheral housing structures  12 W in  FIG.  1    forming a housing assembly). 
     Conductive interconnect structure  97  may extend across (bridge) gap  94  separating display backplate  90  from frame structure  92 . Interconnect structure  97  may connect to display backplate  90  via contacts  104  and may connect to frame structure  92  via contacts  106  and  108 . 
     Slot element  80  formed in frame structure  92  may extend entirely through frame structure  92  in the z-dimension and may have sides defined by corresponding portions of frame structure  92  in the x- and y-dimensions. Contacts  106  may be on one side of slot element  80 , while contacts  108  may be on an opposing side of slot element  80 . 
     The example of  FIG.  8    is merely illustrative. In general, any suitable ground structure in device  10  may include victim frequency rejection structures.  FIG.  9    is cross-sectional side view of device  10 , showing illustrative conductive electronic device structures that may be used in forming one or more portions of an antenna ground (of one or more of antennas  40 ) in device  10 . 
     As shown in  FIG.  9   , peripheral conductive housing structures  12 W may extend around the lateral periphery of device  10  (e.g., as measured in the X-Y plane of  FIG.  1   ). Peripheral conductive housing structures  12 W may extend from rear housing wall  12 R (e.g., at the rear face of device  10 ) to display  14  (e.g., at the front face of device  10 ). In other words, peripheral conductive housing structures  12 W may form conductive sidewalls for device  10 , a first of which is shown in the cross-sectional side view of  FIG.  9    (e.g., a given sidewall that runs along an edge of device  10  and that extends across the width or length of device  10 ). 
     As shown in  FIG.  9   , rear housing wall  12 R may be mounted to peripheral conductive housing structures  12 W (e.g., opposite display  14 ). Rear housing wall  12 R may include a conductive layer such as conductive support plate  112 . Conductive support plate  112  may extend across an entirety of the width of device  10  (e.g., between the left and right edges of device  10  as shown in  FIG.  1   ). Conductive support plate  112  may have an edge that is separated from peripheral conductive housing structures  12 W by dielectric-filled slot  114 . Slot  114  may be filled with air, plastic, ceramic, or other dielectric materials. Conductive support plate  112  may, if desired, provide structural and mechanical support for device  10 . 
     If desired, rear housing wall  12 R may include a dielectric cover layer such as dielectric cover layer  110 . Dielectric cover layer  110  may include glass, plastic, sapphire, ceramic, one or more dielectric coatings, or other dielectric materials. Dielectric cover layer  110  may be layered under conductive support plate  112  (e.g., conductive support plate  112  may be coupled to an interior surface of dielectric cover layer  110 ). If desired, dielectric cover layer  110  may extend across an entirety of the width of device  10  and/or an entirety of the length of device  10 . Dielectric cover layer  110  may overlap slot  114 . 
     Conductive housing structures such as conductive support plate  112  and/or peripheral conductive housing structures  12 W (e.g., the portion of peripheral conductive housing structures  12 W opposite conductive support plate  112  at slot  114 ) may be used to form antenna structures such as antenna ground portions for one or more of antennas  40  in device  10 . For example, conductive support plate  112  may be used to form an antenna ground plane for one or more of antennas  40  in device  10 . One or more portions of peripheral conductive housing structures  12 W may also form corresponding antenna ground portions for one or more of antennas  40  in device  10 . In one illustrative configuration, peripheral conductive housing structures  12 W may include multiple dielectric gaps (e.g., dielectric gaps  18  of  FIG.  1   ) that divide the peripheral conductive housing structures into multiple segments, some of which may serve as or define antenna resonating elements and some of which may serve as an extension of the antenna ground plane formed by support plate  112 . 
     In general, victim frequency rejection structures such as slot element  80  overlapping a grounding interconnect structure with non-ohmic contacts may be formed in any of these ground structure portions described in connection with  FIG.  9    or other ground structure portions in device  10  (e.g., conductive traces on printed circuit boards or other substrates, sheet metal, metal foil, other conductive structures associated with display  14 , other conductive portions of housing  12 , etc. 
       FIG.  10    is a plot showing how the implementation of a victim frequency rejection structure (e.g., slot element  80  as described in connection with  FIGS.  5 - 9   ) may help reduce standing waves (e.g., peak standing wave current amplitude) at a victim frequency. Curve  116  plots peak standing wave current amplitude on a ground structure receiving spurious signals from a grounding interconnect structure with non-ohmic contacts without a victim frequency rejection structure. Curve  118  plots peak standing wave current amplitude on a ground structure having a victim frequency rejection structure (e.g., a slot element in the ground structure with dimension for rejecting a victim frequency F1) when receiving spurious signals containing victim frequency F1. 
     As shown in  FIG.  10   , at victim frequency F1, peak standing wave current amplitude may exhibit a decrease  120  from curve  116  to  118 . In some illustrative examples (e.g., at victim frequencies of 2.4 GHz and/or 5.5 GHz with the implemented elongated slot element having a length 10 mm), decrease  120  may be approximately 15 dB. The example of  FIG.  10    is merely illustrative and, in practice, curves  116  and  118  may have other shapes. 
     Device  10  may gather and/or use personally identifiable information. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20220531
Publication Date: 20241001
Grant Date: 20241001
Priority Date: 20220531
Inventors: RAVICHANDRAN, SIDDHARTH
PRAHALAD, PUNEETH
RAMAKRISHNAN, VIJAYKRISHNAN
SHANBHAG KOTA, SATHISH
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/521", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2291", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/521", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/521", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2291", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 88875798