PATENT DOCUMENT

Publication Number: US-11575209-B2
Application Number: US-202016905498-A
Country: US
Kind Code: B2

Title: Electronic devices having antennas for covering multiple frequency bands

Abstract:
An electronic device may have a first conductive sidewall at an upper end, a second conductive sidewall at a lower end, and a conductive rear wall. First and second antennas may be formed at the upper end and may include slots with edges defined by the first sidewall and the rear wall. Third, fourth, fifth, and sixth antennas may be formed at the lower end and may include slots with edges defined by the second sidewall and the rear wall. Each antenna may cover multiple frequency bands. First order and third order modes of the slots may contribute to the frequency responses of the third through sixth antennas. A display controller may be mounted at the lower end and may impose a lower limit on the frequencies covered by the third through sixth antennas. The first and second antennas may cover lower frequencies than the third through sixth antennas.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a housing having peripheral conductive housing structures and a conductive rear wall, wherein the peripheral conductive housing structures comprise a conductive sidewall; 
 first and second dielectric gaps in the conductive sidewall; 
 a first antenna with a first slot element having edges defined by the conductive sidewall and the conductive rear wall; 
 a second antenna with a second slot element having edges defined by the conductive sidewall and the conductive rear wall, wherein the second slot element has an open end defined by the first dielectric gap; 
 a third antenna with a third slot element having edges defined by the conductive sidewall and the conductive rear wall, wherein the third slot element has an open end defined by the second dielectric gap; and 
 a fourth antenna with a fourth slot element having edges defined by the conductive sidewall and the conductive rear wall, wherein the second and third slot elements are interposed between the first and fourth slot elements. 
 
     
     
       2. The electronic device defined in  claim 1 , further comprising:
 a third dielectric gap in the peripheral conductive housing structures, wherein the first slot element has an open end defined by the third dielectric gap. 
 
     
     
       3. The electronic device defined in  claim 2 , further comprising:
 a fourth dielectric gap in the peripheral conductive housing structures, wherein the fourth slot element has an open end defined by the fourth dielectric gap. 
 
     
     
       4. The electronic device defined in  claim 3 , wherein the first dielectric gap divides the peripheral conductive housing structures into first and second segments, the second dielectric gap separates the second segment from a third segment of the peripheral conductive housing structures, the third dielectric gap separates the first segment from a fourth segment of the peripheral conductive housing structures, the fourth dielectric gap separates the third segment from a fifth segment of the peripheral conductive housing structures, the peripheral conductive housing structures further comprise a first additional conductive sidewall that includes the fourth segment and a portion of the first segment, the peripheral conductive housing structures further comprise a second additional conductive sidewall that includes the fifth segment and a portion of the third segment, the first and second additional conductive sidewalls extend in parallel, and the conductive sidewall extends from the first additional conductive sidewall to the second additional conductive sidewall. 
     
     
       5. The electronic device defined in  claim 3 , wherein the second slot element has a first order mode configured to radiate in a first frequency band and a third order mode configured to radiate in a second frequency band at higher frequencies than the first frequency band. 
     
     
       6. The electronic device defined in  claim 5 , wherein the third slot element has a first order mode configured to radiate in the first frequency band and a third order mode configured to radiate in the second frequency band. 
     
     
       7. The electronic device defined in  claim 6 , wherein the fourth slot element has a first order mode configured to radiate in a third frequency band at lower frequencies than the first frequency band and has a third order mode configured to radiate in the second frequency band. 
     
     
       8. The electronic device defined in  claim 7 , further comprising:
 a tunable component coupled across the fourth slot element, wherein the tunable component has first and second states, the first order mode of the fourth slot element is configured to radiate in the third frequency band when the tunable component is in the first state, and the first order mode of the fourth slot element is configured to radiate in a fourth frequency band at lower frequencies than the first frequency band when the tunable component is in the second state. 
 
     
     
       9. The electronic device defined in  claim 8 , wherein the first slot element has a first order mode configured to radiate in the first frequency band, the third frequency band, the fourth frequency band, and a fifth frequency band at frequencies between the first and fourth frequency bands. 
     
     
       10. The electronic device defined in  claim 9 , wherein the first frequency band comprises a cellular ultra-high band between 3400 and 3800 MHz, the second frequency band comprises a 5 GHz wireless local area network band, the third frequency band comprises a cellular high band between 2300 and 2700 MHz, the fourth frequency band comprises a cellular midband between 1700 and 2200 MHz, and the fifth frequency band comprises a 2.4 GHz wireless local area network band. 
     
     
       11. The electronic device defined in  claim 6 , further comprising:
 a first tunable component coupled across the second slot element, wherein the first tunable component is configured to tune the first order mode of the second slot element without tuning the third order mode of the second slot element; and 
 a second tunable component coupled across the third slot element, wherein the second tunable component is configured to tune the first order mode of the third slot element without tuning the third order mode of the third slot element. 
 
     
     
       12. An electronic device comprising:
 a housing having peripheral conductive housing structures and a conductive wall, wherein the peripheral conductive housing structures comprise first, second, and third conductive sidewalls, the second conductive sidewall extending from the first conductive sidewall to the third conductive sidewall; 
 a first dielectric gap in the first conductive sidewall that divides the peripheral conductive housing structures into first and second segments; 
 a second dielectric gap in the second conductive sidewall that separates the second segment from a third segment of the peripheral conductive housing structures; 
 a third dielectric gap in the second conductive sidewall that separates the third segment from a fourth segment of the peripheral conductive housing structures; 
 a fourth dielectric gap in the third dielectric sidewall that separates the fourth segment from a fifth segment of the peripheral conductive housing structures; 
 a first antenna having a first resonating element arm formed from the second segment, the second segment being separated from the conductive wall by a first slot that extends from the first dielectric gap to the second dielectric gap; and 
 a second antenna having a second resonating element arm formed from the fourth segment, the fourth segment being separated from the conductive wall by a second slot that extends from the third dielectric gap to the fourth dielectric gap. 
 
     
     
       13. The electronic device defined in  claim 12 , further comprising:
 a conductive bridging structure that couples the third segment to the conductive wall, wherein the conductive bridging structure electrically isolates the first and second slots, the second slot has an extension that is interposed between the third segment and the conductive wall, and the extension is configured to perform impedance matching for the second antenna. 
 
     
     
       14. The electronic device defined in  claim 12 , further comprising:
 a first antenna feed coupled to the second segment; 
 a first tunable component coupled to the second segment at a point between the first dielectric gap and the first antenna feed; 
 a second tunable component coupled to the second segment at a point between the second dielectric gap and the first antenna feed; and 
 a third tunable component coupled to the second segment at a point between the second tunable component and the second dielectric gap, wherein the third tunable component is configured to tune a frequency response of the first antenna in a first frequency band, the second tunable component is configured to tune a frequency response of the first antenna in a second frequency band at higher frequencies than the first frequency band, the third tunable component is configured to tune a frequency response of the first antenna in a third frequency band at higher frequencies than the second frequency band, and a harmonic mode of the second segment is configured to radiate in a fourth frequency band at higher frequencies than the third frequency band. 
 
     
     
       15. The electronic device defined in  claim 14 , further comprising:
 a second antenna feed coupled to the fourth segment; 
 a fourth tunable component coupled to the fourth segment at a point between the fourth dielectric gap and the second antenna feed; 
 a fifth tunable component coupled to the fourth segment at a point between the third dielectric gap and the second antenna feed; and 
 a sixth tunable component coupled to the fourth segment at a point between the fifth tunable component and the third dielectric gap, wherein the sixth tunable component is configured to tune a frequency response of the second antenna in the first frequency band, the fifth tunable component is configured to tune a frequency response of the second antenna in the second frequency band, the sixth tunable component is configured to tune a frequency response of the second antenna in the third frequency band, a harmonic mode of the fourth segment is configured to radiate in the fourth frequency band, and a portion of the fourth segment extending from the second antenna feed to the fourth tunable component is configured to radiate in a fifth frequency band at higher frequencies than the second frequency band and at lower frequencies than the fourth frequency band. 
 
     
     
       16. The electronic device defined in  claim 15 , wherein the first frequency band comprises a cellular low band between 900 and 960 MHz, the second frequency band comprises a cellular midband between 1700 and 2200 MHz, the third frequency band comprises a cellular high band between 2300 and 2700 MHz, the fourth frequency band comprises a cellular ultra-high band between 3400 and 3800 MHz, and the fifth frequency band comprises a 2.4 GHz wireless local area network band. 
     
     
       17. An electronic device having opposing first and second ends, comprising:
 peripheral conductive housing structures that include a first conductive sidewall at the first end and a second conductive sidewall at the second end; 
 a conductive housing wall; 
 a display mounted to the peripheral conductive housing structures; 
 a display controller at the second end of the electronic device and configured to control pixel circuitry in the display; 
 first and second antennas at the first end of the electronic device and comprising respective first and second slots with edges defined by the conductive housing wall and the first conductive sidewall; and 
 third, fourth, fifth, and sixth antennas at the second end of the electronic device and comprising respective third, fourth, fifth, and sixth slots having edges defined by the conductive housing wall and the second conductive sidewall. 
 
     
     
       18. The electronic device defined in  claim 17 , wherein:
 the first and second antennas are configured to convey radio-frequency signals in a first frequency band, a second frequency band at higher frequencies than the first frequency band, a third frequency band at higher frequencies than the second frequency band, and a fourth frequency band at higher frequencies than the third frequency band; 
 the second antenna is configured to receive radio-frequency signals in a fifth frequency band at higher frequencies than the first frequency band and lower frequencies than the second frequency band; 
 the second antenna is configured to convey radio-frequency signals in a sixth frequency band at higher frequencies than the second frequency band and lower frequencies than the fourth frequency band; 
 the third antenna is configured to convey radio-frequency signals in the second, third, fourth, and sixth frequency bands; 
 the fourth antenna is configured to convey radio-frequency signals in the fourth frequency band and a seventh frequency band at higher frequencies than the fourth frequency band; 
 the fifth antenna is configured to convey radio-frequency signals in the fourth and seventh frequency bands; and 
 the sixth antenna is configured to convey radio-frequency signals in the second, third, and seventh frequency bands. 
 
     
     
       19. The electronic device defined in  claim 18 , wherein the first, second, third, and sixth antennas are configured to perform four stream (4×) multiple-input and multiple-output (MIMO) operations in the second and third frequency bands, and the first, second, fourth, and fifth antennas are configured to perform 4×MIMO operations in the fourth frequency band. 
     
     
       20. The electronic device defined in  claim 19 , wherein the first frequency band comprises a cellular low band between 600 and 960 MHz, the second frequency band comprises a cellular midband between 1700 and 2200 MHz, the third frequency band comprises a cellular high band between 2300 and 2700 MHz, the fourth frequency band comprises a cellular ultra-high band between 3400 and 3800 MHz, the fifth frequency band comprises a global positioning system (GPS) band between 1565 and 1610 MHz, the sixth frequency band comprises a 2.4 GHz wireless local area network band between 2400 and 2480 MHz, and the seventh frequency band comprises a 5 GHz wireless local area network band between 5180 and 5825 MHz.

Description:
BACKGROUND 
     This relates to electronic devices, and more particularly, to antennas for electronic devices with wireless communications circuitry. 
     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. 
     Because antennas have the potential to interfere with each other and with components in a wireless device, care must be taken when incorporating antennas into an electronic device. Moreover, care must be taken to ensure that the antennas and wireless circuitry in a device are able to exhibit satisfactory performance over a range of operating frequencies and with a satisfactory efficiency bandwidth. In addition, in some devices a single antenna is used to cover a particular frequency band. However, in these scenarios, a single antenna may exhibit insufficient data throughput, particularly when handling communications for data-intensive device applications. 
     It would therefore be desirable to be able to provide improved wireless communications circuitry for wireless electronic devices. 
     SUMMARY 
     An electronic device may be provided with a housing, a display, and wireless circuitry. The housing may include a conductive rear wall and peripheral conductive housing structures. The peripheral conductive housing structures may include a first sidewall at an upper end of the device and a second sidewall at a lower end of the device. The display may be mounted to the peripheral conductive housing structures. A display controller may be mounted at the lower end of the device for driving the display. 
     The wireless circuitry may include first and second antennas at the upper end and third, fourth, fifth, and sixth antennas at the lower end of the device. The first and second antennas may include first and second slots with edges defined by the first conductive sidewall and the rear wall. The first and second slots may each have a pair of open ends defined by dielectric gaps in the peripheral conductive housing structures. The first and second antennas may have resonating element arms formed from segments of the first conductive sidewall. The third, fourth, fifth, and sixth antennas may include respective third, fourth, fifth, and sixth slots with edges defined by the second conductive sidewall and the rear wall. The third, fourth, fifth, and sixth slots may each have a single open end defined by dielectric gaps in the peripheral conductive housing structures. 
     The first and second antennas may each have at least three tunable components. The first and second antennas may convey signals in a cellular low band, a cellular low-midband, a cellular midband, a cellular high band, and a cellular ultra-high band. The second antenna may also convey signals in a 2.4 GHz wireless local area network (WLAN) band and may receive signals in a satellite navigations band. The presence of the display controller at the lower end of the device may prevent the third, fourth, fifth, and sixth antennas from covering the cellular low band or the cellular low-midband. The third, fourth, fifth, and sixth antennas may each include at least one tunable component. First order and/or higher order modes (e.g., third order modes) of the third, fourth, fifth, and sixth antennas may contribute to the frequency responses of the antennas. The third antenna may convey signals in the cellular midband, the cellular ultra-high band, and the 2.4 GHz WLAN band. The fourth and fifth antennas may convey signals in the cellular ultra-high band and a 5 GHz WLAN band. The sixth antenna may convey signals in the cellular midband, the cellular high band, and the 5 GHz WLAN band. Multiple-input and multiple-output (MIMO) schemes may be used by any combination of the antennas in any of these frequency bands to maximize data throughput. 
    
    
     
       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 diagram of illustrative wireless circuitry including multiple antennas at different ends of an electronic device accordance with some embodiments. 
         FIG.  4    is a schematic diagram of illustrative inverted-F antenna structures in accordance with some embodiments. 
         FIG.  5    is a schematic diagram of illustrative open slot antenna structures in accordance with some embodiments. 
         FIG.  6    is a top view of illustrative antennas located at an upper end of an electronic device in accordance with some embodiments. 
         FIG.  7    is a top view of illustrative antennas located at a lower end of an electronic device in accordance with some embodiments. 
         FIG.  8    is a chart of illustrative frequency bands that may be covered by the illustrative antennas of  FIGS.  3 - 7    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. 
     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, 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. 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. 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. Peripheral structures  12 W and 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 sidewalls, 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 lip 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 ). 
     If desired, rear housing wall  12 R may be formed from a metal such as stainless steel or aluminum and may sometimes be referred to herein as conductive rear housing wall  12 R or conductive rear wall  12 R. Conductive rear housing wall  12 R may lie in a plane that is parallel to display  14 . In configurations for device  10  in which the rear housing wall 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 the conductive rear housing wall of housing  12 . For example, conductive rear housing wall  12 R of device  10  may be formed from 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 . Conductive 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 the conductive 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 structures  12 W and/or  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 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. 
     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  8  or a microphone port. Speaker port  8  may be omitted if desired. 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 a display module having 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  (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). Conductive rear housing wall  12 R may, for example form the backplate of housing  12 . 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. 
     At ends (regions)  16  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 conductive 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 ends  20  and  16  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 ends  20  and  16 . 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 ends  20  and  16 ), thereby narrowing the slots in ends  20  and  16 . 
     In general, device  10  may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device  10  may be located at opposing first and second ends of an elongated device housing (e.g., at ends  20  and  16  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  18  such as gaps  18 - 1 ,  18 - 2 ,  18 - 3 ,  18 - 4 ,  18 - 5 ,  18 - 6 ,  18 - 7 , and  18 - 8 , 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. The gaps may divide peripheral conductive housing structures  12 W into one or more peripheral conductive segments. There may be, for example, two peripheral conductive segments in peripheral conductive housing structures  12 W (e.g., in an arrangement with two gaps  18 ), three peripheral conductive segments (e.g., in an arrangement with three gaps  18 ), four peripheral conductive segments (e.g., in an arrangement with four gaps  18 ), six peripheral conductive segments (e.g., in an arrangement with six gaps  18 ), eight peripheral conductive segments (e.g., in an arrangement with eight gaps  18 ), etc. The segments of peripheral conductive housing structures  12 W that are formed in this way may form parts of antennas in device  10 . 
     The gaps in peripheral conductive housing structures  12 W may be formed along different sides of device  10 . In the example of  FIG.  1   , device  10  has a substantially rectangular outline. Peripheral conductive housing structures  12 W include a first conductive sidewall at a first (e.g., left) edge of device  10 , a second conductive sidewall at a second (e.g., top) edge of device  10 , a third conductive sidewall at a third (e.g., right) edge of device  10 , and a fourth conductive sidewall at a fourth (e.g., bottom) edge of device  10  (e.g., where the first conductive sidewall extends parallel to the third conductive sidewall and the Y-axis and where the second and fourth conductive sidewalls extend in parallel between the first and third conductive sidewalls). Gaps  18 - 5  and  18 - 1  may be formed in the first conductive sidewall. Gaps  18 - 2  and  18 - 3  may be formed in the second conductive sidewall. Gaps  18 - 4  and  18 - 8  may be formed in the third conductive sidewall. Gaps  18 - 6  and  18 - 7  may be formed in the fourth conductive sidewall. Gaps  18 - 1 ,  18 - 2 ,  18 - 3 , and  18 - 4  may be formed in peripheral conductive housing structures  12 W at upper end  16  of device  10 . Gaps  18 - 5 ,  18 - 6 ,  18 - 7 , and  18 - 8  may be formed in peripheral conductive housing structures  12 W at lower end  20  of device  10 . This example is merely illustrative. 
     If desired, openings in housing  12  such as grooves that extend partway or completely through housing  12  may extend across the width of the rear wall of housing  12  and may penetrate through the rear wall of housing  12  to divide the rear wall into different portions. These grooves may also extend into peripheral conductive housing structures  12 W and may form antenna slots, gaps  18 , and other structures in device  10 . Polymer or other dielectric may fill these grooves and other housing openings. In some situations, housing openings that form antenna slots and other structures may be filled with a dielectric such as air. 
     In a typical scenario, device  10  may have one or more upper antennas and one or more lower antennas (as an example). An upper antenna may, for example, be formed at upper end  16  of device  10 . A lower antenna may, for example, be formed at lower end  20  of device  10 . The antennas may be used separately to cover identical communications bands, overlapping communications bands, or separate communications bands. The antennas may be used to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme. Antennas in device  10  may be used to support any communications bands of interest. For example, device  10  may include antenna structures for supporting local area network communications, voice and data cellular telephone communications, global positioning system (GPS) communications or other satellite navigation system communications, Bluetooth® communications, near-field communications, ultra-wideband communications, etc. 
     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 of ends  20  and  16  that is available for forming antennas within device  10 . In general, antennas that are provided with larger operating volumes or spaces may have higher bandwidth efficiency than antennas that are provided with smaller operating volumes or spaces. If care is not taken, increasing the size of active area AA may reduce the operating space available to the antennas, which can undesirably inhibit the efficiency bandwidth of the antennas (e.g., such that the antennas no longer exhibit satisfactory radio-frequency performance). 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 operate with optimal efficiency bandwidth. 
     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  24 . Control circuitry  24  may include storage such as storage circuitry  28 . Storage circuitry  28  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  24  may include processing circuitry such as processing circuitry  26 . Processing circuitry  26  may be used to control the operation of device  10 . Processing circuitry  26  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  24  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  28  (e.g., storage circuitry  28  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  28  may be executed by processing circuitry  26 . 
     Control circuitry  24  may be used to run software on device  10  such as satellite navigation applications, 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  24  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  24  include internet protocols, wireless local area network (WLAN) protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other wireless personal area network (WPAN) protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols (e.g., global positioning system (GPS) protocols, global navigation satellite system (GLONASS) protocols, etc.), or any other desired communications protocols. Each communications 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  30 . Input-output circuitry  30  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch sensors, displays (e.g., touch-sensitive displays), light-emitting components such as displays without touch sensor capabilities, buttons (mechanical, capacitive, optical, etc.), scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, audio jacks and other audio port components, digital data port devices, motion sensors (accelerometers, gyroscopes, and/or compasses that detect motion), capacitance sensors, proximity sensors, magnetic sensors, force sensors (e.g., force sensors coupled to a display to detect pressure applied to the display), etc. In some configurations, keyboards, headphones, displays, pointing devices such as trackpads, mice, and joysticks, and other input-output devices may be coupled to device  10  using wired or wireless connections (e.g., some of input-output devices  32  may be peripherals that are coupled to a main processing unit or other portion of device  10  via a wired or wireless link). 
     Input-output circuitry  30  may include wireless circuitry  34  to support wireless communications. Wireless circuitry  34  may include radio-frequency (RF) transceiver circuitry  36  formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas such as antenna  40 , transmission lines such as transmission line  38 , and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). While control circuitry  24  is shown separately from wireless circuitry  34  in the example of  FIG.  1    for the sake of clarity, wireless circuitry  34  may include processing circuitry that forms a part of processing circuitry  26  and/or storage circuitry that forms a part of storage circuitry  28  of control circuitry  24  (e.g., portions of control circuitry  24  may be implemented on wireless circuitry  34 ). As an example, control circuitry  24  (e.g., processing circuitry  26 ) may include baseband processor circuitry or other control components that form a part of wireless circuitry  34 . 
     Radio-frequency transceiver circuitry  36  may include wireless local area network transceiver circuitry that handles WLAN communications 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) and a 5 GHz WLAN band (e.g., from 5180 to 5825 MHz). Radio-frequency transceiver circuitry  36  may also include wireless personal area network transceiver circuitry that handles the 2.4 GHz Bluetooth® band or other WPAN communications bands. If desired, radio-frequency transceiver circuitry  36  may handle other bands such as cellular telephone bands, near-field communications bands (e.g., at 13.56 MHz), satellite navigations bands (e.g., a GPS band from 1565 to 1610 MHz), millimeter or centimeter wave bands (e.g., from 10 to 300 GHz), and/or other communications bands. The cellular telephone bands handled by radio-frequency transceiver circuitry  36  may include a cellular low band (LB) (e.g., from 600 to 960 MHz), a cellular low-midband at higher frequencies than the cellular low band (e.g., from 1400 to 1550 MHz), a cellular midband at higher frequencies than the cellular low-midband (e.g., from 1565 to 1610 MHz), a cellular high band at higher frequencies than the cellular midband (e.g., from 2300 to 2700 MHz), and/or a cellular ultra-high band at higher frequencies than the cellular high band (e.g., from 3400 to 3800 MHz). If desired, radio-frequency transceiver circuitry  36  may also include ultra-wideband (UWB) transceiver circuitry that supports communications using the IEEE 802.15.4 protocol and/or other ultra-wideband communications protocols. Communications bands may sometimes be referred to herein as frequency bands or simply as “bands” and may span corresponding ranges of frequencies. 
     Wireless circuitry  34  may include one or more antennas such as antenna  40 . In general, radio-frequency transceiver circuitry  36  may be configured to cover (handle) any suitable communications (frequency) bands of interest. Radio-frequency transceiver circuitry  36  may convey radio-frequency signals using antennas  40  (e.g., antennas  40  may convey the radio-frequency signals for radio-frequency transceiver circuitry  36 ). 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. 
     As shown in  FIG.  2   , radio-frequency transceiver circuitry  36  may be coupled to antenna feed  42  of antenna  40  using transmission line  38 . Antenna feed  42  may include a positive antenna feed terminal such as positive antenna feed terminal  44  and may include a ground antenna feed terminal such as ground antenna feed terminal  46 . Transmission line  38  may be formed from metal traces on a printed circuit, cables, or other conductive structures. Transmission line  38  may have a positive transmission line signal path such as path  48  that is coupled to positive antenna feed terminal  44 . Transmission line  38  may have a ground transmission line signal path such as path  50  that is coupled to ground antenna feed terminal  46 . Path  48  may sometimes be referred to herein as signal conductor  48  and path  50  may sometimes be referred to herein as ground conductor  50 . 
     Transmission line paths such as transmission line  38  may be used to route antenna signals within device  10  (e.g., to convey radio-frequency signals between radio-frequency transceiver circuitry  36  and antenna feed  42  of antenna  40 ). Transmission lines in device  10  may include coaxial cables, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, transmission lines formed from combinations of transmission lines of these types, etc. Transmission lines in device  10  such as transmission line  38  may be integrated into rigid and/or flexible printed circuit boards. In one suitable arrangement, transmission lines such as transmission line  38  may also include transmission line conductors (e.g., signal conductors  48  and ground conductors  50 ) 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). The multilayer laminated structures may, if desired, be folded or bent in multiple dimensions (e.g., two or three dimensions) and may 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). 
     To provide antenna structures such as antenna  40  with the ability to cover communications frequencies of interest, antenna  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna  40  may be provided with adjustable circuits such as tunable (T) components  52  to tune the antenna over frequency band(s) of interest. Tunable components  52  may be part of a tunable filter or tunable impedance matching network, may be part of an antenna resonating element, may span a gap between an antenna resonating element and antenna ground, etc. 
     Tunable components  52  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. During operation of device  10 , control circuitry  24  may issue control signals on one or more paths such as path  22  that adjust inductance values, capacitance values, or other parameters associated with tunable components  52 , thereby tuning antenna  40  to cover desired communications bands. A matching network (e.g., an adjustable matching network formed using tunable components  52 ) may include components such as inductors, resistors, and capacitors used in matching the impedance of antenna  40  to the impedance of transmission line  38 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna  40  and may be tunable and/or fixed components. 
     During operation, control circuitry  24  may use radio-frequency transceiver circuitry  36  and antenna(s)  40  to transmit and/or receive data wirelessly. Control circuitry  24  may, for example, receive wireless local area network communications wirelessly using radio-frequency transceiver circuitry  36  and antenna(s)  40  and may transmit wireless local area network communications wirelessly using radio-frequency transceiver circuitry  36  and antenna(s)  40 . 
     Control circuitry  24  may use information from a proximity sensor (e.g., sensors in input-output devices  32 ), wireless performance metric data such as received signal strength information, device orientation information from an orientation sensor, device motion data from an accelerometer or other motion detecting sensor, information about a usage scenario of device  10 , information about whether audio is being played through a speaker, information from one or more antenna impedance sensors, and/or other information in determining when antenna  40  is being affected by the presence of nearby external objects or is otherwise in need of tuning. In response, control circuitry  24  may adjust an adjustable inductor, adjustable capacitor, switch, or other tunable component  52  and/or may switch one or more antennas  40  into or out of use to ensure that wireless circuitry  34  operates as desired. 
     The presence or absence of external objects such as a user&#39;s hand may affect antenna loading and therefore antenna performance. Antenna loading may differ depending on the way in which device  10  is being held. For example, antenna loading and therefore antenna performance may be affected in one way when a user is holding device  10  in a portrait orientation and may be affected in another way when a user is holding device  10  in a landscape orientation. To accommodate various loading scenarios, device  10  may use sensor data, antenna measurements, information about the usage scenario or operating state of device  10 , and/or other data from input-output devices  32  to monitor for the presence of antenna loading (e.g., the presence of a user&#39;s hand, the user&#39;s head, or another external object). Device  10  (e.g., control circuitry  24 ) may then adjust tunable components  52  in antenna  40  and/or may switch other antennas into or out of use to compensate for the loading (e.g., multiple antennas  40  may be operated using a diversity protocol to ensure that at least one antenna  40  may maintain satisfactory communications even while the other antennas are blocked by external objects). Adjustments to tunable components  52  may also be made to extend the coverage of antenna structures  40  (e.g., to cover desired communications bands that extend over a range of frequencies larger than the antenna structures would cover without tuning). 
     In the example of  FIG.  2   , a single antenna is shown. When operating using a single antenna, a single stream of wireless data may be conveyed between device  10  and external communications equipment (e.g., one or more other wireless devices such as wireless base stations, access points, cellular telephones, computers, etc.). This may impose an upper limit on the data rate (data throughput) obtainable by wireless circuitry  34  in communicating with the external communications equipment. As software applications and other device operations increase in complexity over time, the amount of data that needs to be conveyed between device  10  and the external communications equipment typically increases, such that a single antenna may not be capable of providing sufficient data throughput for handling the desired device operations. 
     In order to increase the overall data throughput of wireless circuitry  34 , multiple antennas may be operated using a multiple-input and multiple-output (MIMO) scheme. When operating using a MIMO scheme, two or more antennas on device  10  may be used to convey multiple independent streams of wireless data at the same frequencies. This may significantly increase the overall data throughput between device  10  and the external communications equipment relative to scenarios where only a single antenna is used. In general, the greater the number of antennas that are used for conveying wireless data under the MIMO scheme, the greater the overall throughput of wireless circuitry  34 . 
       FIG.  3    is a diagram showing how device  10  may include multiple antennas  40  for performing wireless communications (e.g., using a MIMO scheme). As shown in  FIG.  3   , device  10  may include two or more antennas  40  such as a first antenna  40 U- 1 , a second antenna  40 U- 2 , a third antenna  40 L- 1 , a fourth antenna  40 L- 2 , a fifth antenna  40 L- 3 , and a sixth antenna  40 L- 4 . This example is merely illustrative and, in general, device  10  may include nay desired number of antennas  40 . 
     Antennas  40  may be provided at different locations within housing  12  of device  10 . For example, antennas  40 U- 1  and  40 U- 2  may be formed at upper end  16  whereas antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  are formed at lower end  20 . Antennas  40 U- 1  and  40 U- 2  may therefore sometimes be referred to herein as upper antennas  40 U- 1  and  40 U- 2  (or collectively as upper antennas  40 U), whereas antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  may sometimes be referred to herein as lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 4 , and  40 L- 4  (or collectively as lower antennas  40 L). 
     Wireless circuitry  34  may include input-output ports such as port  54  for interfacing with digital data circuits in storage and processing circuitry (e.g., control circuitry  24  of  FIG.  2   ). Wireless circuitry  34  may include baseband circuitry such as baseband (BB) processor  56  and radio-frequency transceiver circuitry such as transceiver (TX/RX) circuitry  36 . Port  54  may receive digital data from the control circuitry that is to be transmitted by transceiver circuitry  36 . Incoming data that has been received by transceiver circuitry  36  and baseband processor  56  may be supplied to the control circuitry via port  54 . 
     Transceiver circuitry  36  may include one or more discrete transmitters and one or more discrete receivers if desired. Transceiver circuitry  36  may include multiple transceiver ports  58  that are each coupled to a corresponding transmission line  38  (e.g., a first transmission line  38 - 1 , a second transmission line  38 - 2 , a third transmission line  38 - 3 , a fourth transmission line  38 - 4 , a fifth transmission line  38 - 5 , and a sixth transmission line  38 - 6 ). Transmission line  38 - 1  may couple a first transceiver port  58  of transceiver circuitry  36  to upper antenna  40 U- 1 . 
     Transmission line  38 - 2  may couple a second transceiver port  58  to upper antenna  40 U- 2 . Similarly, transmission lines  38 - 3 ,  38 - 4 ,  38 - 5 , and  38 - 6  may couple corresponding transceiver ports  58  of transceiver circuitry  36  to lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4 , respectively. 
     Radio-frequency front end circuits  60  may be interposed on each transmission line  38  (e.g., a first front end circuit  60 - 1  may be interposed on transmission line  38 - 1 , a second front end circuit  60 - 2  may be interposed on transmission line  38 - 2 , a third front end circuit  60 - 3  may be interposed on transmission line  38 - 3 , etc.). Front end circuits  60  may each include switching circuitry, filter circuitry (e.g., duplexer and/or diplexer circuitry, notch filter circuitry, low pass filter circuitry, high pass filter circuitry, bandpass filter circuitry, etc.), impedance matching circuitry for matching the impedance of transmission line  38  to the corresponding antenna  40 , networks of active and/or passive components such as tunable components  52  of  FIG.  2   , radio-frequency coupler circuitry for gathering antenna impedance measurements, or any other desired radio-frequency circuitry. If desired, front end circuits  60  may include switching circuitry that is configured to selectively couple antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  to different respective transceiver ports  58  (e.g., so that each antenna can handle communications for different transceiver ports  58  over time based on the state of the switching circuits in front end circuits  60 ). 
     If desired, front end circuits  60  may include filtering circuitry (e.g., duplexers and/or diplexers) that allow the corresponding antenna to transmit and receive radio-frequency signals at the same time (e.g., using a frequency domain duplexing (FDD) scheme). Antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  may transmit and/or receive radio-frequency signals in respective time slots or two or more of antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  may transmit and/or receive radio-frequency signals concurrently. In general, any desired combination of antennas may transmit and/or receive radio-frequency signals at a given time. 
     Amplifier circuitry such as one or more power amplifiers may be interposed on transmission lines  38  and/or formed within transceiver circuitry  36  for amplifying radio-frequency signals output by transceiver circuitry  36  prior to transmission over antennas  40 . Amplifier circuitry such as one or more low noise amplifiers may be interposed on transmission lines  38  and/or formed within transceiver circuitry  36  for amplifying radio-frequency signals received by antennas  40  prior to conveying the received signals to transceiver circuitry  36 . 
     In the example of  FIG.  3   , separate front end circuits  60  are formed on each transmission line  38 . This is merely illustrative. If desired, two or more transmission lines  38  may share the same front end circuits  60  (e.g., front end circuits  60  may be formed on the same substrate, module, or integrated circuit). 
     Transceiver circuitry  36  may, for example, include circuitry for converting baseband signals received from baseband processor  56  into corresponding radio-frequency signals. For example, transceiver circuitry  36  may include mixer circuitry for up-converting the baseband signals to radio-frequencies prior to transmission over antennas  40 . Transceiver circuitry  36  may include digital to analog converter (DAC) and/or analog to digital converter (ADC) circuitry for converting signals between digital and analog domains. Transceiver circuitry  36  may include circuitry for converting radio-frequency signals received from antennas  40  over transmission lines  38  into corresponding baseband signals. For example, transceiver circuitry  36  may include mixer circuitry for down-converting the radio-frequency signals to baseband frequencies prior to conveying the baseband signals to baseband processor  56 . Baseband processor  56 , front end circuits  60 , and/or transceiver circuitry  36  may be formed on the same substrate, integrated circuit, integrated circuit package, or module or two or more of these components may be formed on separate substrates, integrated circuits, integrated circuit packages, or modules. 
     Device  10  may include display controller circuitry such as display controller  61 . Display controller  61  may be used in controlling display  14  of device  10  ( FIG.  1   ). For example, display controller  61  may drive pixel circuitry in the display to emit images using the display. Display controller  61  may also include touch sensor circuitry that gathers touch sensor data from the display. Display controller circuitry  61  may be implemented on an integrated circuit chip or printed circuit board, as examples. One or more display flexible printed circuits may couple display controller  61  to the display. 
     Display controller  61  may be located at or adjacent to lower end  20  of device  10  (e.g., display controller  61  may be located adjacent to lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4 , with some or all of display controller  61  overlapping lower end  20  of device  10 ). In general, greater antenna volumes support operations at longer wavelengths (lower frequencies). However, display controller  61  may occupy a relatively large amount of space in device  10 . The presence of display controller  61  may limit the volume of lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  such that display controller  61  imposes a lower limit on the frequencies coverable by the lower antennas. This may, for example, prevent lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  from being able to cover relatively low frequencies such as frequencies within the cellular low band and/or the cellular low-midband. 
     Because display controller  61  is located at the opposite side of device  10  from upper antennas  40 U- 1  and  40 U- 2 , upper antennas  40 U- 1  and  40 U- 2  may each occupy a larger space (e.g., a larger area or volume within device  10 ) than lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4 . This may allow upper antennas  40 U- 1  and  40 U- 2  to support communications at longer wavelengths (i.e., lower frequencies) than lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4 . Upper antennas  40 U- 1  and  40 U- 2  may, for example, each cover the cellular low band and the cellular low-midband. This is merely illustrative and, if desired, each of the antennas may occupy the same volume or may occupy different volumes. Antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and/or  40 L- 4  may be configured to convey radio-frequency signals in at least one common frequency band. If desired, one or more of antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  may handle radio-frequency signals in at least one frequency band that is not covered by one or more of the other antennas in device  10 . 
     If desired, each antenna  40  may handle radio-frequency communications in multiple frequency bands (e.g., multiple cellular telephone communications and/or WLAN bands). In one suitable arrangement that is sometimes described herein as an example, the cellular low band and cellular low-midband may be covered by upper antennas  40 U- 1  and  40 U- 2 , the GPS band may be covered by upper antenna  40 U- 2 , the cellular midband and cellular high band may be covered by antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 , and  40 L- 4 , the 2.4 GHz WLAN band and the 2.4 GHz WPAN band may be covered by antennas  40 U- 2  and  40 L- 1 , the cellular ultra-high band may be covered by antennas  40 U- 1 ,  40 U- 2 ,  40 L- 2 , and  40 L- 3 , and the 5 GHz WLAN band may be covered by lower antennas  40 L- 2 ,  40 L- 3 , and  40 L- 4 . This is merely illustrative. In general, antennas  40  may cover any desired frequency bands. Device  10  may include any desired number of antennas  40 . Housing  12  may have any desired shape. 
     In order to perform wireless communications under a MIMO scheme, antennas  40  need to convey data at the same frequencies. If desired, wireless circuitry  34  may perform so-called two-stream (2×) MIMO operations (sometimes referred to herein as 2×MIMO communications or communications using a 2×MIMO scheme) in which two antennas  40  are used to convey two independent streams of radio-frequency signals at the same frequency. Wireless circuitry  34  may perform so-called four-stream (4×) MIMO operations (sometimes referred to herein as 4×MIMO communications or communications using a 4×MIMO scheme) in which four antennas  40  are used to convey four independent streams of radio-frequency signals at the same frequency. Performing 4×MIMO operations may support higher overall data throughput than 2×MIMO operations because 4×MIMO operations involve four independent wireless data streams whereas 2×MIMO operations involve only two independent wireless data streams. If desired, upper antennas  40 U- 1  and  40 U- 2  may perform 2×MIMO operations in the cellular low band and cellular low-midband, antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 , and  40 L- 4  may perform up to 4×MIMO operations in the cellular midband and the cellular high band, antennas  40 U- 2  and  40 L- 1  may perform 2×MIMO operations in the 2.4 GHz WLAN band, antennas  40 U- 1 ,  40 U- 2 ,  40 L- 2 , and  40 L- 3  may perform up to 4×MIMO operations in the cellular ultra-high band, and lower antennas  40 L- 2 ,  40 L- 3 , and/or  40 L- 4  may perform 2×MIMO operations in the 5 GHz WLAN band. In this way, antennas  40  may perform MIMO operations to greatly increase the possible data throughput of wireless circuitry  34 . 
     Antennas  40  (e.g., antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and/or  40 L- 4  of  FIG.  3   ) may include slot antenna structures (e.g., open slot antenna structures or closed slot antenna structures), inverted-F antenna structures (e.g., planar and non-planar inverted-F antenna structures), loop antenna structures, combinations of these, or any other desired antenna structures. In one suitable arrangement that is described herein as an example, each of upper antennas  40 U- 1  and  40 U- 2  may be formed using inverted-F antenna structures. Antennas that are implemented using inverted-F antenna structures may sometimes be referred to herein as inverted-F antennas. 
       FIG.  4    is a schematic diagram of inverted-F antenna structures that may be used to form the upper antennas and/or any other desired antennas  40  in device  10 . As shown in  FIG.  4   , antenna  40  (e.g., one of upper antennas  40 U- 1  and  40 U- 2  of  FIG.  3   ) may include an antenna resonating element such as antenna resonating element  62  and an antenna ground such as antenna ground  68 . Antenna resonating element  62  may include a resonating element arm  64  (sometimes referred to herein as antenna resonating element arm  64 , radiating arm  64 , radiating element arm  64 , antenna arm  64 , or arm  64 ) that is shorted to antenna ground  68  by return path  66 . Antenna  40  may be fed by coupling a transmission line (e.g., transmission line  38  of  FIG.  2   ) to positive antenna feed terminal  44  and ground antenna feed terminal  46  of antenna feed  42 . Positive antenna feed terminal  44  may be coupled to resonating element arm  64  and ground antenna feed terminal  46  may be coupled to antenna ground  68 . Return path  66  may be coupled between resonating element arm  64  and antenna ground  69  in parallel with antenna feed  42 . 
     The length of resonating element arm  64  may determine the response (e.g., resonant) frequency of the antenna. For example, the length of resonating element arm  64  may be approximately equal to (e.g., within 15% of) one-quarter of an effective wavelength corresponding to a frequency in the frequency band of operation of antenna  40  (e.g., where the effective wavelength is equal to a free space wavelength multiplied by a constant value associated with the dielectric material surrounding antenna  40 ). In the example of  FIG.  4   , antenna  40  includes only a single resonating element arm  64 . This is merely illustrative. If desired, antenna  40  may include any desired number of resonating element arms or branches having any desired shapes and following any desired paths (e.g., for conveying signals in multiple frequency bands). One or more tunable components such as tunable components  52  of  FIG.  2    may be coupled between resonating element arm  64  and antenna ground  68  or elsewhere on antenna  40  to tune antenna  40  to cover one or more desired frequency bands. One or more harmonic modes of resonating element arm  64  may also be used to increase the number of frequency bands covered by antenna  40 . 
     In one suitable arrangement that is described herein as an example, each of lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  of  FIG.  3    may be formed using open slot antenna structures. Antennas that are implemented using open slot antenna structures may sometimes be referred to herein as open slot antennas (e.g., slot antennas having radiating elements formed from slots with an open end). 
       FIG.  5    is a schematic diagram of open slot antenna structures that may be used to form the lower antennas and/or any other desired antennas  40  in device  10 . As shown in  FIG.  5   , antenna  40  (e.g., a given one of lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  of  FIG.  3   ) may include a conductive structure such as conductive structure  71  that has been provided with a dielectric-filled opening such as dielectric opening  70 . Opening  70  may sometimes be referred to herein as slot  70 , slot element  70 , slot radiating element  70 , slot resonating element  70 , antenna slot  70 , or slot antenna resonating element  70 . 
     In some scenarios, slot  70  is a closed slot where conductive structure  71  completely surrounds and encloses slot  70  (e.g., where an entirety of the lateral periphery of slot  70  is defined by conductive structure  71 ). In the example of  FIG.  5    in which antenna  40  is an open slot antenna, slot  70  has an open end  74  that is free from conductive material (e.g., slot  70  may protrude through conductive structure  71 ). As shown in  FIG.  5   , slot  70  may have a first edge  72  (sometimes referred to herein as a closed end of slot  70 ) opposite open end  74 . Slot  70  may have a longitudinal (e.g., longest) axis extending from first edge  72  to open end  74 . Slot  70  may also have a third edge  75  and a fourth edge  73  (e.g., extending parallel to the longitudinal axis of slot  70  from first edge  72  to open end  74 ). Conductive structure  71  may define edges  72 ,  73 , and  75  of slot  70 . Slot  70  may have a length L measured parallel to the longitudinal axis of slot  70 . 
     Antenna feed  42  may be coupled across slot  70  at a distance D from first edge  72 . Distance D may be adjusted to match the impedance of antenna  40  to the impedance of the corresponding transmission line (e.g., transmission line  38  of  FIG.  2   ). Distance D may be between first edge  72  and the center  77  of slot  70  (as measured along length L), at a location where the antenna current experiences an impedance that matches the impedance of the corresponding transmission line, for example. 
     Slot  70  may be characterized by multiple electromagnetic standing wave modes that are associated with different response peaks for antenna  40 . These discrete modes may be determined by the dimensions of slot  70  (e.g., length L). For example, the dimensions of slot  70  may define the boundary conditions for electromagnetic standing waves in each of the standing wave modes that are excited on slot  70  by antenna currents conveyed over antenna feed  42  and/or by received radio-frequency signals. Such standing wave modes of slot  70  include a first order (e.g., fundamental) mode and one or more higher order modes (e.g., harmonics of the first order mode). Slot  70  may exhibit antenna performance (efficiency) peaks at frequencies associated with the first order mode and one or more higher order modes of slot  70 . 
     Curves  76  and  78  are shown on  FIG.  5    to illustrate some of the standing wave modes of slot  70 . As shown in  FIG.  5   , curves  76  and  78  plot the voltage across slot  70  (perpendicular to length L) at different points along length L. Similarly, curves  76  and  78  may also represent the magnitude of the electric field E 0  within slot  70  at different points along length L (e.g., where electric field E 0  extends in a direction perpendicular to length L). In each mode, nodes in the voltage distribution are present at first edge  72  of slot  70  (e.g., length L establishes boundary conditions for the electromagnetic standing waves produced on slot  70  in the different modes). 
     Curve  76  represents the voltage distribution across slot  70  in a first order mode (sometimes referred to herein as the fundamental mode or λ/4 mode of slot  70 ). As shown by curve  76 , in the first order mode, the voltage across slot  70  and the magnitude of electric field E 0  reach a maximum (e.g., an anti-node) at open end  74  (e.g., at length L from first edge  72 ). Length L may be selected to be approximately equal to one-quarter of the effective wavelength corresponding to a frequency in a first frequency band of operation of antenna  40  (e.g., length L may be approximately equal to λ/4, where λ is the effective wavelength corresponding to a frequency in the first frequency band). The effective wavelength is equal to a free space wavelength multiplied by a constant factor determined by the dielectric material filling slot  70 . 
     Higher order modes of slot  70  (e.g., harmonic modes of the first order mode shown by curve  76 ) such as a third order mode may also configure slot  70  to radiate in at least a second frequency band. Curve  78  represents the voltage distribution across slot  70  in a third order mode (sometimes referred to herein as a harmonic mode or 3λ/4 mode of slot  70 ). As shown by curve  78 , in the third order mode, the voltage across slot  70  and the magnitude of electric field E 0  reach maxima at open end  74  and between center  77  and first edge  72 . In the third order mode, the voltage across slot  70  and the magnitude of electric field E 0  reach a minimum (e.g., a node) at distance  79  from the center  77  of slot  70 . The third order mode may configure slot  70  to cover at least a second frequency band at higher frequencies than the first frequency band covered by the first order mode (e.g., a frequency band that includes a frequency corresponding to an effective wavelength equal to 3λ/4). 
     This example in which length L is selected to be approximately equal to one-quarter of the effective wavelength corresponding to a frequency in the first frequency band and the third order mode is used to cover the second frequency band is merely illustrative. In another suitable arrangement, length L may be selected so that slot  70  exhibits a third order mode in the second frequency band. For example, length L may be selected so that length L is approximately equal to 3λ/4, where λ is an effective wavelength corresponding to a frequency in the second frequency band. However, if care is not taken, selecting length L based on the third order harmonic in this way may create a first order mode that is located outside of the first frequency band. 
     In order to recover a response peak in the first frequency band, a tunable component may be coupled across slot  70  to re-align the first order mode with the first frequency band. For example, a tunable component (e.g., tunable component  52  of  FIG.  2   ) may be coupled across slot  70  (e.g., between edges  73  and  75 ) at distance  79  from center  77 . Coupling the tunable component across slot  70  at this location may cause the tunable component to tune the first order mode without tuning the third order mode of slot  70  (e.g., because the first order mode has a non-zero voltage magnitude at distance  79  from center  77  whereas the third order mode has a node at distance  79  from center  77 ). The tunable component may serve to tune the first order mode to align with the first frequency band, thereby recovering a response peak for slot  70  in the first frequency band. This may thereby configure slot  70  to radiate with satisfactory antenna efficiency in both the first frequency band (e.g., due to the re-tuned first order mode) and the second frequency band (e.g., due to the third order mode established by length L). As just one example, the first frequency band may include the cellular ultra-high band from 3400 to 3800, the cellular midband from 1700 to 2200 MHz, and/or the cellular high band from 2300 to 2700 MHz, whereas the second frequency band is the 5 GHz WLAN band from 5180 to 5825 MHz. If desired, the tunable component may also be adjusted in real time between a first state in which the first order mode covers the cellular midband and a second state in which the first order mode covers the cellular high band. In yet another suitable arrangement, the first order mode may cover each of the cellular midband, cellular high band, and 2.4 GHz WLAN and WPAN bands, where the tunable component may be switched to optimize the response of the antenna in each of these bands as needed. 
     The example of  FIG.  5    is merely illustrative. In general, slot  70  may have any desired shape (e.g., having any desired number of curved and/or straight segments). For example, slot  70  may have a meandering shape with different segments extending in different directions, may have straight and/or curved edges, may have more than one open end, etc. Conductive structure  71  may be formed from any desired conductive electronic device structures. For example, conductive structure  71  may include conductive traces on printed circuit boards or other substrates, sheet metal, metal foil, conductive structures associated with display  14  ( FIG.  1   ), conductive portions of housing  12  (e.g., portions of peripheral conductive housing structures  12 W and/or conductive rear housing wall  12 R of  FIG.  1   ), and/or other conductive structures within device  10 . In one suitable arrangement, different sides (edges) of slot  70  may be defined by different conductive structures. For example, edge  73  of slot  70  may be defined by conductive rear housing wall  12 R whereas edge  75  is defined by peripheral conductive housing structures  12 W. 
       FIG.  6    is a top interior view of upper end  16  of device  10  in which upper antennas  40 U- 1  and  40 U- 2  are located for performing wireless communications (e.g., using a MIMO scheme). As shown in  FIG.  6   , device  10  may have peripheral conductive housing structures such as peripheral conductive housing structures  12 W. In the example of  FIG.  6   , display  14  is not shown for the sake of clarity. 
     Gap  18 - 1  may be formed in the left sidewall of peripheral conductive housing structures  12 W. Gaps  18 - 2  and  18 - 3  may be formed in the top sidewall of peripheral conductive housing structures  12 W. Gap  18 - 4  may be formed in the right sidewall of peripheral conductive housing structures  12 W. Gap  18 - 1  may separate segment  88  of peripheral conductive housing structures  12 W from segment  80  of peripheral conductive housing structures  12 W. Segment  80  may include both a portion of the left sidewall and a portion of the top sidewall of peripheral conductive housing structures  12 W. Gap  18 - 2  may separate segment  80  from segment  82  of peripheral conductive housing structures  12 W. Gap  18 - 3  may separate segment  82  from segment  84  of peripheral conductive housing structures  12 W. Segment  84  may include both a portion of the top sidewall and a portion of the right sidewall of peripheral conductive housing structures  12 W. Gap  18 - 4  may separate segment  84  from segment  86  of peripheral conductive housing structures  12 W. Gaps  18 - 1 ,  18 - 2 ,  18 - 3 , and  18 - 4  may be filled with plastic, ceramic, sapphire, glass, epoxy, or other dielectric materials. The dielectric material in these gaps may lie flush with peripheral conductive housing sidewalls  12 W at the exterior surface of device  10  if desired. 
     A conductive structure such as conductive layer  114  may extend between the left and right sidewalls of peripheral conductive housing structures  12 W. Conductive layer  114  may be formed from conductive housing structures, conductive structures from electrical device components in device  10 , printed circuit board traces, strips of conductor such as strips of wire and metal foil, conductive components in a display (e.g., display  14  of  FIG.  1   ), and/or other conductive structures (e.g., conductive layer  114  need not be confined to a single plane). In one suitable arrangement, conductive layer  114  is formed from conductive rear housing wall  12 R of  FIG.  1   . Conductive layer  114  may sometimes be referred to herein as support plate  114  or backplate  114 . 
     As shown in  FIG.  6   , conductive layer  114  (e.g., conductive rear housing wall  12 R) may extend between the opposing edges (e.g., the left and right edges) of device  10 . Conductive layer  114  may be formed from a separate metal structure from peripheral conductive housing structures  12 W or conductive layer  114  and peripheral conductive housing structures  12 W may be formed from the same, continuous, integral metal structure (e.g., in a unibody configuration). Conductive layer  114  and segments  88  and  86  of peripheral conductive housing structures  12 W may be held at a ground potential and may form the antenna ground for upper antennas  40 U- 1  and  40 U- 2 . 
     Segment  80  may be separated from conductive layer  114  by slot  90 . Slot  90  may have a first end defined by gap  18 - 1  and an opposing second end defined by gap  18 - 2  (e.g., slot  90  may be continuous with gaps  18 - 1  and  18 - 2 ). Upper antenna  40 U- 1  may, for example, be an inverted-F antenna having a resonating element arm formed from segment  80  (e.g., segment  80  may form resonating element arm  64  of  FIG.  4    for upper antenna  40 U- 1 ). Conductive layer  114  and segments  88  and  86  may form the antenna ground for upper antenna  40 U- 1  (e.g., antenna ground  68  of  FIG.  4   ). 
     Upper antenna  40 U- 1  may be fed by a corresponding antenna feed  42 - 1  coupled across slot  90 . Positive antenna feed terminal  44 - 1  of antenna feed  42 - 1  may be coupled to segment  80  whereas ground antenna feed terminal  46 - 1  is coupled to conductive layer  114 . Impedance matching circuitry (M) such as impedance matching circuitry  92  may be coupled between positive antenna feed terminal  44 - 1  and segment  80 . Matching circuitry  92  may be adjustable to tune the frequency response of upper antenna  40 U- 1 . Matching circuitry  92  may, for example, include an inductor and a switchable capacitor coupled in parallel between positive antenna feed terminal  44 - 1  and ground. The switchable capacitor may be switched into or out of use to adjust the tuning of upper antenna  40 U- 1 . 
     Tunable components such as tunable components  94 ,  96 , and  98  (e.g., tunable components  52  of  FIG.  2   ) may be coupled between segment  80  and conductive layer  114  across slot  90 . Tunable component  94  may be coupled to a point on segment  80  between antenna feed  42 - 1  and gap  18 - 1 . Tunable component  98  may be coupled to a point on segment  80  between antenna feed  42 - 1  and gap  18 - 2 . Tunable component  96  may be coupled to a point on segment  80  between antenna feed  42 - 1  and tunable component  98 . 
     Upper antenna  40 U- 1  may be a multi-band antenna that covers multiple frequency bands. Different portions of segment  80  may radiate in different frequency bands. For example, the length of the portion of segment  80  extending from antenna feed  42 - 1  to gap  18 - 1  may be selected to support a resonance in the cellular high band (e.g., antenna currents flowing on this portion of segment  80  in the cellular high band may radiate corresponding radio-frequency signals), the length of the portion of segment  80  extending from antenna feed  42 - 1  to tunable component  96  may be selected to support a resonance in the cellular midband, and the length of segment  80  from gap  18 - 1  to gap  18 - 2  may be selected to support a resonance in the cellular low band and cellular low-midband. These lengths of segment  80  may, for example, be selected to cover these frequency bands in a first order (fundamental) mode. One or more harmonic modes of these lengths may also configure upper antenna  40 U- 1  to cover additional frequency bands. For example, a fifth harmonic mode of the length of segment  80  from gap  18 - 1  to gap  18 - 2  and/or a third harmonic mode of the portion of segment  80  extending from antenna feed  42 - 1  to tunable component  96  may radiate in the cellular ultra-high band. 
     Tunable components  94 ,  96 , and  98  may each tune a frequency response of upper antenna  40 U- 1  in these frequency bands. Tunable components  94 ,  96 , and  98  may each include any desired number of capacitors, resistors, inductors, and/or switches coupled in any desired manner between segment  80  and conductive layer  114 . As an example, tunable component  94  may include two or more switchable inductors coupled in parallel between segment  80  and conductive layer  114 . Tunable component  94  may, for example, help to set the radiating length of segment  80  in the cellular low band and/or may tune the frequency response of upper antenna  40 U- 1  in the cellular high band. Tunable component  96  may, for example, include a capacitor (e.g., a fixed capacitor coupled across slot  90 ). The capacitance of tunable component  96  may help to tune the frequency response of upper antenna  40 U- 1  in the cellular midband. Tunable component  98  may, for example, include multiple switchable inductors (e.g., four switchable inductors) coupled in parallel between segment  80  and conductive layer  114 . The inductors in tunable component  98  may be switched into or out of use to tune a frequency response of upper antenna  40 U- 1  between and/or within the cellular low band and cellular low-midband. These examples are merely illustrative and, in general, any desired tunable components may be coupled to segment  80  for supporting resonances in any desired number of frequency bands at any desired frequencies. Tunable components  94 ,  96 , and/or  98  and/or matching circuitry  92  may be mounted to one or more shared or separate substrates (e.g., flexible printed circuits, rigid printed circuit boards, etc.). 
     Segment  84  of peripheral conductive housing structures  12 W may be separated from conductive layer  114  by slot  104 . Slot  104  may have a first end defined by gap  18 - 3  and an opposing second end defined by gap  18 - 4  (e.g., slot  104  may be continuous with gaps  18 - 3  and  18 - 4 ). If desired, slot  104  may include an extended portion  106  interposed between segment  82  and conductive layer  114 . Extended portion  106  of slot  104  may, for example, serve to improve the impedance matching and/or extend the bandwidth of upper antenna  40 U- 2 . Upper antenna  40 U- 2  may, for example, be an inverted-F antenna having a resonating element arm formed from segment  84  (e.g., segment  84  may form resonating element arm  64  of  FIG.  4    for upper antenna  40 U- 2 ). Conductive layer  114  and segments  88  and  86  may form the antenna ground for upper antenna  40 U- 2  (e.g., antenna ground  68  of  FIG.  4   ). 
     Conductive bridging structures such as conductive structures  100  may be coupled between segment  82  of peripheral conductive housing structures  12 W and conductive layer  114 . Conductive structures  100  may electrically isolate slot  90  from slot  104  (e.g., conductive structures  100  may define edges or closed ends of slots  90  and  104 ). Conductive structures  100  may, as examples, be formed from metal traces on printed circuits, metal foil, metal members formed from a sheet of metal, conductive portions of housing  12  (e.g., integral portions of conductive rear housing wall  12 R and/or peripheral conductive housing structures  12 W), conductive wires, conductive portions of input-output devices  32  of  FIG.  2    (e.g., conductive portions of display  14  of  FIG.  1   , conductive portions of a camera module or light sensor module, conductive portions of a speaker module, conductive portions of a data port such as a universal serial bus port, etc.), conductive interconnect structures such as conductive pins, conductive brackets, conductive adhesive, solder, welds, conductive springs, conductive screws, or combinations of these and/or other conductive interconnect structures, conductive foam, switchable or fixed inductive paths (e.g., one or more switchable inductors), switchable or fixed capacitive paths (e.g., one or more switchable capacitors), and/or any other desired conductive components or structures. 
     Slots  90  and  104  may be filled with plastic, glass, sapphire, epoxy, ceramic, or other dielectric material. In one suitable arrangement, slots  90  and  104  may be formed from a single continuous dielectric-filled slot at the exterior of device  10  (e.g., where a single continuous piece of dielectric material is used to fill slots  90  and  104  as well as gaps  18 - 1 ,  18 - 2 ,  18 - 3 , and  18 - 4 ). In this scenario, conductive structures  100  may be formed at the interior of device  10  and may serve to electrically divide the continuous dielectric-filled slot into separate slots  90  and  104  (e.g., at the interior of device  10 ). 
     Upper antenna  40 U- 2  may be fed by a corresponding antenna feed  42 - 2  coupled across slot  104 . Positive antenna feed terminal  44 - 2  of antenna feed  42 - 2  may be coupled to segment  84  whereas ground antenna feed terminal  46 - 2  is coupled to conductive layer  114 . Tunable components such as tunable components  102 ,  108 , and  110  (e.g., tunable components  52  of  FIG.  2   ) may be coupled between segment  84  and conductive layer  114  across slot  104 . Tunable component  102  may be coupled to a point on segment  84  between antenna feed  42 - 2  and gap  18 - 3 . Tunable component  108  may be coupled to a point on segment  84  between antenna feed  42 - 2  and tunable component  102 . Tunable component  110  may be coupled to a point on segment  84  between antenna feed  42 - 2  and gap  18 - 4 . 
     Upper antenna  40 U- 2  may be a multi-band antenna that covers multiple frequency bands. Different portions of segment  84  may radiate in different frequency bands. For example, the length of the portion of segment  84  extending from antenna feed  42 - 2  to gap  18 - 4  may be selected to support a resonance in the cellular high band (e.g., antenna currents flowing on this portion of segment  84  in the cellular high band may radiate corresponding radio-frequency signals), the length of the portion of segment  80  extending from antenna feed  42 - 2  to tunable component  108  may be selected to support a resonance in the cellular midband, and the length of segment  84  from gap  18 - 3  to gap  18 - 4  may be selected to support a resonance in the cellular low band and cellular low-midband. The cellular low-midband and/or cellular midband resonances of upper antenna  40 U- 2  may also cover a satellite navigations frequency band such as a GPS frequency band. The cellular high band resonance of upper antenna  40 U- 2  (e.g., the portion of segment  84  extending between antenna feed  42 - 2  and tunable component  110 ) may also cover the 2.4 GHz WLAN band and the 2.4 GHz WPAN band. One or more harmonic modes of segment  84  may also configure upper antenna  40 U- 2  to cover additional frequency bands. For example, a fifth harmonic mode of the length of segment  80  from gap  18 - 3  to gap  18 - 4  and/or a third harmonic mode of the portion of segment  80  extending from antenna feed  42 - 2  to tunable component  108  may radiate in the cellular ultra-high band. 
     Tunable components  102 ,  108 , and  110  may each tune a frequency response of upper antenna  40 U- 2  in these frequency bands. Tunable components  102 ,  108 , and  110  may each include any desired number of capacitors, resistors, inductors, and/or switches coupled in any desired manner between segment  84  and conductive layer  114 . Tunable component  110  may, for example, help to set the radiating length of segment  84  in the cellular low band and/or may tune the frequency response of upper antenna  40 U- 2  in the cellular high band. Tunable component  108  may, for example, tune the frequency response of upper antenna  40 U- 2  in the cellular midband. Tunable component  102  may, for example, tune the frequency response of upper antenna  40 U- 2  between and/or within the cellular low band and the cellular low-midband. These examples are merely illustrative and, in general, any desired tunable components may be coupled to segment  80  for supporting resonances in any desired number of frequency bands at any desired frequencies. Tunable components  102 ,  108 , and/or  110  may be mounted to one or more shared or separate substrates (e.g., flexible printed circuits, rigid printed circuit boards, etc.). 
     If desired, an input-output device such as camera module  112  may be mounted to conductive layer  114  adjacent to upper antenna  40 U- 2 . If care is not taken, the presence of conductive material in camera module  112  can undesirably detune upper antenna  40 U- 2 . Tunable components  102 ,  108 ,  110 , and/or other tunable components in upper antenna  40 U- 2  may help to compensate for potential detuning by camera module  112 . 
       FIG.  7    is a top interior view of lower end  20  of device  10 , in which lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  are located for performing wireless communications (e.g., using a MIMO scheme). As shown in  FIG.  7   , gap  18 - 5  may be formed in the left sidewall of peripheral conductive housing structures  12 W. Gaps  18 - 6  and  18 - 7  may be formed in the bottom sidewall of peripheral conductive housing structures  12 W. Gap  18 - 8  may be formed in the right sidewall of peripheral conductive housing structures  12 W. 
     Gap  18 - 5  may separate segment  88  of peripheral conductive housing structures  12 W from segment  130  of peripheral conductive housing structures  12 W. Segment  130  may include both a portion of the left sidewall and a portion of the bottom sidewall of peripheral conductive housing structures  12 W. Gap  18 - 6  may separate segment  130  from segment  132  of peripheral conductive housing structures  12 W. Gap  18 - 7  may separate segment  132  from segment  134  of peripheral conductive housing structures  12 W. Segment  134  may include both a portion of the bottom sidewall and a portion of the right sidewall of peripheral conductive housing structures  12 W. Gap  18 - 8  may separate segment  134  from segment  86  of peripheral conductive housing structures  12 W. Gaps  18 - 5 ,  18 - 6 ,  18 - 7 , and  18 - 8  may be filled with plastic, ceramic, sapphire, glass, epoxy, or other dielectric materials. The dielectric material in these gaps may lie flush with peripheral conductive housing structures  12 W at the exterior surface of device  10  if desired. 
     Segment  130  may be separated from conductive layer  114  by slots  116  and  118 . Segment  134  may be separated from conductive layer  114  by slots  120  and  122 . Conductive bridging structures such as conductive structures  124  may be coupled between segment  130  of peripheral conductive housing structures  12 W and conductive layer  114 . Conductive bridging structures such as conductive structures  126  may be coupled between segment  132  and conductive layer  114 . Conductive bridging structures such as conductive structures  128  may be coupled between segment  134  and conductive layer  114 . 
     Conductive structures  124  may electrically isolate slot  116  from slot  118  (e.g., conductive structures  124  may define edges or closed ends of slots  116  and  118 ). Conductive structures  126  may electrically isolate slot  118  from slot  120 . Conductive structures  128  may electrically isolate slot  120  from slot  122  (e.g., conductive structures  128  may define edges or closed ends of slots  120  and  122 ). Conductive structures  124 ,  126 , and  128  may, as examples, be formed from metal traces on printed circuits, metal foil, metal members formed from a sheet of metal, conductive portions of housing  12  (e.g., integral portions of conductive rear housing wall  12 R and/or peripheral conductive housing structures  12 W), conductive wires, conductive portions of input-output devices  32  of  FIG.  2    (e.g., conductive portions of display  14  of  FIG.  1   , conductive portions of a camera module or light sensor module, conductive portions of a speaker module, conductive portions of a data port such as a universal serial bus port, etc.), conductive interconnect structures such as conductive pins, conductive brackets, conductive adhesive, solder, welds, conductive springs, conductive screws, or combinations of these and/or other conductive interconnect structures, conductive foam, switchable or fixed inductive paths (e.g., one or more switchable inductors), switchable or fixed capacitive paths (e.g., one or more switchable capacitors), and/or any other desired conductive components or structures. 
     Slots  116 ,  118 ,  120 , and  122  may be filled with plastic, glass, sapphire, epoxy, ceramic, or other dielectric material. In one suitable arrangement, slots  116 ,  118 ,  120 , and  122  may be formed from a single continuous dielectric-filled slot at the exterior of device  10  (e.g., where a single continuous piece of dielectric material is used to fill slots  116 ,  118 ,  120 , and  122  as well as gaps  18 - 5 ,  18 - 6 ,  18 - 7 , and  18 - 8 ). In this scenario, conductive structures  124 ,  126 , and  128  may be formed at the interior of device  10  and may serve to electrically divide the continuous dielectric-filled slot into separate slots  116 ,  118 ,  120 , and  122  (e.g., at the interior of device  10 ). 
     As shown in  FIG.  7   , lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  may each be open slot antennas. Lower antenna  40 L- 1  may be fed by a corresponding antenna feed  42 - 3  coupled across slot  116 . Positive antenna feed terminal  44 - 3  of antenna feed  42 - 3  may be coupled to segment  130  whereas ground antenna feed terminal  46 - 3  is coupled to conductive layer  114 . Slot  116  may form the radiating element for lower antenna  40 L- 1 . For example, slot  116  may form slot  70  of  FIG.  5    for lower antenna  40 L- 1 , where segment  130 , conductive structures  124 , and conductive layer  114  form conductive structure  71  of  FIG.  5    (e.g., edge  75  of  FIG.  5    may be defined by conductive layer  114  whereas edge  73  of  FIG.  5    is defined by segment  130 ). 
     Slot  116  of  FIG.  7    may be an open slot. Conductive structures  124  may form the closed end of slot  116  (e.g., first edge  72  of  FIG.  5   ). Gap  18 - 5  may form the open end of slot  116  (e.g., open end  74  of  FIG.  5   ). In other words, gap  18 - 5  may be continuous with slot  116 . The length of slot  116  (e.g., length L of  FIG.  5   ) may be determined by the length of slot  116  extending from conductive structures  124  to gap  18 - 5 . The vertical height of gap  18 - 5  (e.g., parallel to the Z-axis of  FIG.  7   ) may also contribute to the length of slot  116  if desired. In this example, slot  116  has a first portion extending from conductive structures  124  to the left sidewall of peripheral conductive housing structures  12 W (parallel to the X-axis), a second portion extending from an end of the first portion to gap  18 - 5  (parallel to the Y-axis), and a third portion extending from an end of the second portion up the height of gap  18 - 5  (parallel to the Z-axis), where the first, second, and third portions define the length of the slot. This is merely illustrative and, in general, slot  116  may have any desired shape with any desired number of curved and/or straight portions having any desired number of curved and/or straight edges. 
     A tunable component such as tunable component  136  (e.g., tunable component  52  of  FIG.  2   ) may be coupled between segment  130  and conductive layer  114  across slot  116 . Tunable component  136  may be coupled to a point on segment  130  between antenna feed  42 - 3  and gap  18 - 5 . Lower antenna  40 L- 1  may be a multi-band antenna that covers multiple frequency bands. The length of slot  116  may be selected so that slot  116  radiates in the cellular midband (e.g., from 1700 to 2200 MHz), the cellular high band (e.g., from 2300 to 2700 MHz), the 2.4 GHz WLAN band (e.g., from 2400 to 2480 MHz), and the 2.4 GHz WPAN band (e.g., using the same standing wave mode such as the first order mode of slot  116 ). Tunable component  136  may be adjusted to optimize the frequency response in one or more of these bands at any given time as needed. 
     Lower antenna  40 L- 2  may be fed by a corresponding antenna feed  42 - 4  coupled across slot  118 . Positive antenna feed terminal  44 - 4  of antenna feed  42 - 4  may be coupled to segment  130  whereas ground antenna feed terminal  46 - 4  is coupled to conductive layer  114 . Slot  118  may form the radiating element for lower antenna  40 L- 2 . For example, slot  118  may form slot  70  of  FIG.  5    for lower antenna  40 L- 2 , where segment  130 , conductive structures  124 , conductive structures  126 , and conductive layer  114  form conductive structure  71  of  FIG.  5    (e.g., edge  73  of  FIG.  5    may be defined by segment  130  whereas edge  75  of  FIG.  5    is defined by conductive layer  114  and conductive structures  126 ). 
     Slot  118  of  FIG.  7    may be an open slot. Conductive structures  124  may form the closed end of slot  118  (e.g., first edge  72  of  FIG.  5   ). Gap  18 - 6  may form the open end of slot  118  (e.g., open end  74  of  FIG.  5   ). In other words, gap  18 - 6  may be continuous with slot  118 . The length of slot  118  (e.g., length L of  FIG.  5   ) may be determined by the length of slot  118  extending from conductive structures  124  to gap  18 - 6 . The vertical height of gap  18 - 6  (e.g., parallel to the Z-axis of  FIG.  7   ) may also contribute to the length of slot  118  if desired. In this example, slot  118  has a first portion extending from conductive structures  124  to gap  18 - 6  (parallel to the X-axis) and a second portion extending from an end of the first portion up the height of gap  18 - 6  (parallel to the Z-axis), where the first and second portions define the length of the slot. This is merely illustrative and, in general, slot  118  may have any desired shape with any desired number of curved and/or straight portions having any desired number of curved and/or straight edges. 
     Lower antenna  40 L- 2  may be a multi-band antenna that covers multiple frequency bands. For example, the length of slot  118  may be selected so that slot  118  has a first order mode that radiates in the cellular ultra-high band from 3400 to 3800 MHz. A higher order mode such as a third order mode may configure slot  118  to radiate in an additional frequency band such as the 5 GHz WLAN band. 
     A tunable component such as tunable component  138  (e.g., tunable component  52  of  FIG.  2   ) may be coupled between segment  130  and conductive layer  114  across slot  118 . Tunable component  138  may be coupled to a point on segment  130  between antenna feed  42 - 4  and gap  18 - 6 . Tunable component  138  may, for example, be coupled across slot  118  at a location where the third order mode of slot  118  exhibits a voltage or electric field node (e.g., at distance  79  from the center  77  of the slot as shown in  FIG.  5   ). This may configure tunable component  138  to tune the first order mode frequency response of slot  118  in the cellular ultra-high band (e.g., so that lower antenna  40 L- 2  exhibits satisfactory antenna efficiency across the cellular ultra-high band) without affecting the third order mode frequency response of slot  118  in the 5 GHz WLAN band. 
     Lower antenna  40 L- 3  may be fed by a corresponding antenna feed  42 - 5  coupled across slot  120 . Positive antenna feed terminal  44 - 5  of antenna feed  42 - 5  may be coupled to segment  134  whereas ground antenna feed terminal  46 - 5  is coupled to conductive layer  114 . Slot  120  may form the radiating element for lower antenna  40 L- 3 . For example, slot  120  may form slot  70  of  FIG.  5    for lower antenna  40 L- 3 , where segment  134 , conductive structures  126 , conductive structures  128 , and conductive layer  114  form conductive structure  71  of  FIG.  5    (e.g., edge  73  of  FIG.  5    may be defined by segment  134  whereas edge  75  of  FIG.  5    is defined by conductive layer  114  and conductive structures  126 ). 
     Slot  120  of  FIG.  7    may be an open slot. Conductive structures  128  may form the closed end of slot  120  (e.g., first edge  72  of  FIG.  5   ). Gap  18 - 7  may form the open end of slot  120  (e.g., open end  74  of  FIG.  5   ). In other words, gap  18 - 7  may be continuous with slot  120 . The length of slot  120  (e.g., length L of  FIG.  5   ) may be determined by the length of slot  120  extending from conductive structures  128  to gap  18 - 7 . The vertical height of gap  18 - 7  (e.g., parallel to the Z-axis of  FIG.  7   ) may also contribute to the length of slot  120  if desired. In this example, slot  120  has a first portion extending from conductive structures  128  to gap  18 - 7  (parallel to the X-axis) and a second portion extending from an end of the first portion up the height of gap  18 - 7  (parallel to the Z-axis), where the first and second portions define the length of the slot. This is merely illustrative and, in general, slot  120  may have any desired shape with any desired number of curved and/or straight portions having any desired number of curved and/or straight edges. 
     Lower antenna  40 L- 3  may be a multi-band antenna that covers multiple frequency bands. For example, the length of slot  120  may be selected so that slot  120  has a first order mode that radiates in the cellular ultra-high band from 3400 to 3800 MHz. A higher order mode such as a third order mode may configure slot  120  to radiate in an additional frequency band such as the 5 GHz WLAN band. 
     A tunable component such as tunable component  140  (e.g., tunable component  52  of  FIG.  2   ) may be coupled between segment  134  and conductive layer  114  across slot  120 . Tunable component  140  may be coupled to a point on segment  134  between antenna feed  42 - 5  and gap  18 - 7 . Tunable component  140  may, for example, be coupled across slot  120  at a location where the third order mode of slot  120  exhibits a voltage or electric field node (e.g., at distance  79  from the center  77  of the slot as shown in  FIG.  5   ). This may configure tunable component  140  to tune the first order mode frequency response of slot  120  in the cellular ultra-high band (e.g., so that lower antenna  40 L- 3  exhibits satisfactory antenna efficiency across the cellular ultra-high band) without affecting the third order mode frequency response of slot  120  in the 5 GHz WLAN band. 
     Lower antenna  40 L- 4  may be fed by a corresponding antenna feed  42 - 6  coupled across slot  122 . Positive antenna feed terminal  44 - 6  of antenna feed  42 - 6  may be coupled to segment  134  whereas ground antenna feed terminal  46 - 6  is coupled to conductive layer  114 . Slot  122  may form the radiating element for lower antenna  40 L- 4 . For example, slot  122  may form slot  70  of  FIG.  5    for lower antenna  40 L- 4 , where segment  134 , conductive structures  128 , and conductive layer  114  form conductive structure  71  of  FIG.  5    (e.g., edge  73  of  FIG.  5    may be defined by segment  134  whereas edge  75  of  FIG.  5    is defined by conductive layer  114 ). 
     Slot  122  of  FIG.  7    may be an open slot. Conductive structures  128  may form the closed end of slot  122  (e.g., first edge  72  of  FIG.  5   ). Gap  18 - 8  may form the open end of slot  122  (e.g., open end  74  of  FIG.  5   ). In other words, gap  18 - 8  may be continuous with slot  122 . The length of slot  122  (e.g., length L of  FIG.  5   ) may be determined by the length of slot  122  extending from conductive structures  128  to gap  18 - 8 . The vertical height of gap  18 - 8  (e.g., parallel to the Z-axis of  FIG.  7   ) may also contribute to the length of slot  122  if desired. In this example, slot  122  has a first portion extending from conductive structures  128  to the right sidewall of peripheral conductive housing structures  12 W (parallel to the X-axis), a second portion extending from an end of the first portion to gap  18 - 8  (parallel to the Y-axis), and a third portion extending from an end of the second portion up the height of gap  18 - 8  (parallel to the Z-axis), where the first, second, and third portions define the length of the slot. This is merely illustrative and, in general, slot  122  may have any desired shape with any desired number of curved and/or straight portions having any desired number of curved and/or straight edges. 
     Lower antenna  40 L- 4  may be a multi-band antenna that covers multiple frequency bands. For example, the length of slot  122  may be selected so that slot  122  has a third order mode that radiates in the 5 GHz WLAN band from (e.g., from 5180 to 5825 MHz). A lower order mode such as the first order mode may configure slot  122  to radiate in additional frequency bands such as the cellular midband and the cellular high band. 
     A tunable component such as tunable component  142  (e.g., tunable component  52  of  FIG.  2   ) may be coupled between segment  134  and conductive layer  114  across slot  122 . Tunable component  142  may be coupled to a point on segment  134  between antenna feed  42 - 6  and gap  18 - 8 . Tunable component  142  may, for example, be coupled across slot  122  at a location where the third order mode of slot  122  exhibits a voltage or electric field node (e.g., at distance  79  from the center  77  of the slot as shown in  FIG.  5   ). This may configure tunable component  142  to tune the first order mode frequency response of slot  120  without affecting the third order mode frequency response of slot  122  in the 5 GHz WLAN band. As one example, tunable component  142  may have first and second states. When placed in the first state, the tunable component may configure the first order mode of slot  122  to radiate in the cellular midband (e.g., affecting the third order mode frequency response of slot  122  in the 5 GHz WLAN band). When placed in the second state, the tunable component may configure the first order mode of slot  122  to radiate in the cellular high band (e.g., without affecting the third order mode frequency response of slot  122  in the 5 GHz WLAN band). 
     As shown in  FIG.  7   , conductive layer  114  may have a protruding portion  135  that extends beyond gaps  18 - 5  and  18 - 8  (e.g., as measured parallel to the Y-axis). Display controller  61  may be located adjacent to lower antennas  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  at lower end  20  of device  10 . Some, none, or all of display controller  61  may, if desired, overlap protrusion  135  of conductive layer  114 . The presence of display controller  61  may prevent the lower antennas from having sufficient volume to cover the cellular low band or the cellular low-midband. 
     One or more substrates such as one or more flexible printed circuits and/or rigid printed circuit boards may be used for mounting tunable components  136 ,  138 ,  140 , and/or  142 . As one example, tunable components  136  and  138  of lower antennas  40 L- 1  and  40 L- 2  may be mounted to a first flexible printed circuit whereas tunable components  140  and  142  of lower antennas  40 L- 3  and  40 L- 4  are mounted to a second flexible printed circuit. The first flexible printed circuit may carry transmission line structures that couple antenna feeds  42 - 3  and  42 - 4  to transceiver circuitry  36  of  FIG.  3   . The second flexible printed circuit may carry transmission line structures that couple antenna feeds  42 - 5  and  42 - 6  to transceiver circuitry  36  of  FIG.  3   . 
       FIG.  8    shows a table  144  that illustrates how antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 ,  40 L- 2 ,  40 L- 3 , and  40 L- 4  of  FIGS.  3 - 7    may collectively cover each frequency band of operation for device  10 . Column  146  of table  144  lists different frequency bands of operation for device  10 . Column  148  of table  144  lists exemplary frequency ranges corresponding to the frequency bands in column  146 . Column  150  lists the antennas that are able to cover each of the frequency bands in column  146 . Column  152  lists the MIMO operations supported for each of the frequency bands in column  146 . 
     As shown by table  144 , upper antennas  40 U- 1  and  40 U- 2  may cover the cellular low band (e.g., from 600 to 960 MHz) and the cellular low-midband (e.g., from 1400 to 1550 MHz). Upper antennas  40 U- 1  and  40 U- 2  may support up to 2×MIMO operations in the cellular low band and/or in the cellular low-midband. Upper antenna  40 U- 2  may cover the GPS band (e.g., from 1565 to 1610 MHz). Upper antennas  40 U- 1  and  40 U- 2  and lower antennas  40 L- 1  and  40 L- 4  may cover the cellular midband (e.g., from 1700 to 2200 MHz) and the cellular high band (e.g., from 2300 to 2700 MHz). Antennas  40 U- 1 ,  40 U- 2 ,  40 L- 1 , and  40 L- 4  may support up to 4×MIMO operations in the cellular midband and/or in the cellular high band. Upper antenna  40 U- 2  and lower antenna  40 L- 1  may cover the 2.4 GHz WLAN band and the 2.4 GHz WPAN band (e.g., from 2400 to 2480 MHz). Antennas  40 U- 2  and  40 L- 1  may support up to 2×MIMO operations in the 2.4 GHz WLAN band. Upper antennas  40 U- 1  and  40 U- 2  and lower antennas  40 L- 2 , and  40 L- 3  may cover the cellular ultra-high band (e.g., from 3400 to 3800 MHz). Antennas  40 U- 1 ,  40 U- 2 ,  40 L- 2 , and  40 L- 3  may support up to 4×MIMO operations in the cellular ultra-high band. Finally, lower antennas  40 L- 2 ,  40 L- 3 , and  40 L- 4  may cover the 5 GHz WLAN band (e.g., from 5180 to 5825 MHz). Antennas  40 L- 2 ,  40 L- 3 , and  40 L- 4  may support up to 2×MIMO operations in the 5 GHz WLAN band. 
     In this way, each of the antennas may collectively cover each of these frequency bands of operation with satisfactory antenna efficiency and maximal data throughput. The example of  FIG.  8    is merely illustrative. In general, device  10  may include any desired number of antennas for covering any desired number of frequency bands at any desired frequencies. 
     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: 20200618
Publication Date: 20230207
Grant Date: 20230207
Priority Date: 20200618
Inventors: Garrido Lopez, David
LI, AOBO
HASNAT, FORHAD
RAJAGOPALAN, HARISH
ASKARIAN AMIRI, MIKAL
GOMEZ ANGULO, RODNEY A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q13/18", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0413", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/18", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q21/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/0413", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/50", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 79022019