Antennas of an electronic device with conductive display structures

Abstract

Electronic device (10) comprising: a housing (12) with peripheral conductive structures (16); a display (14) in the housing (12); a conductive frame (308) for the display (14); an antenna resonant element arm (108) for an antenna (40), the antenna resonant element arm (108) being formed from a segment of the peripheral conductive structures (16); and an antenna ground (103) for the antenna (40) comprising the conductive frame (308) for the display (14), characterized in that the conductive frame (308) has a first portion separated from the antenna resonating element arm (108) by a first distance and a second portion separated from the antenna resonating element arm (108) by a second distance that is smaller than the first distance, and the second portion is configured to form a distributed capacitance with the antenna resonating element arm (108).

Description

BACKGROUNDThis relates generally to electronic devices, and more particularly to electronic devices with wireless communication circuitry.Electronic devices often include wireless communication circuitry. For example, mobile phones, computers, and other devices often include antennas and wireless transceivers for supporting wireless communication.U.S. Pat. No. 9,024,823 B2 relates to an electronic device having a wireless communication circuit and a dynamically adjustable antenna which supports a plurality of antenna modes.US 2011 0254 741 A1 relates to a wireless communication device having a housing element which functions as a radiation element of an antenna.It may be challenging to form electronic device antenna structures with desired characteristics. In some wireless devices, antennas are bulky. In other devices, antennas are compact but sensitive to the position of the antennas relative to external objects. Unless care is taken, antennas may be detuned, output wireless signals with a power less than or greater than desired, or otherwise not operate as expected.It would therefore be desirable to be able to provide improved wireless circuitry for electronic devices.SUMMARYThe invention is defined in claim 1. Advantageous embodiments are defined in the dependent claims. An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. The antennas may include antenna structures at opposing first and second ends of the electronic device. The antenna structures at a given end of the device may include adjustable components that are adjusted by the control circuitry to bring the antenna structures and the electronic device into one of a number of different modes of operation or states.An antenna in the electronic device may include a reverse F antenna resonating element formed from portions of a peripheral conductive housing structure of the electronic device, and may include an antenna ground separated from the antenna resonating element by a gap. A short circuit path may bridge the gap. An antenna feed can be connected across the gap parallel to the short circuit path.The antenna ground for the antenna may include a lead frame for the display. The lead frame may include a first portion separated from the antenna resonating element arm by a first distance and a second portion separated from the antenna resonating element arm by a second distance less than the first distance. The second portion may be configured to form a distributed impedance matching capacitance with the antenna resonating element arm. The antenna feed may include a positive feed terminal coupled to the antenna resonating element arm via the second portion of the leadframe.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a perspective view of an illustrative electronic device according to an embodiment. FIG. 2 is a schematic diagram of illustrative circuitry in an electronic device according to an embodiment. FIG. 3 is a schematic diagram of illustrative wireless communication circuitry, according to an embodiment. FIG. 4 is a schematic diagram of an illustrative inverted-F antenna according to an embodiment. FIG. 5 is a diagram of illustrative antenna structures in an electronic device according to an embodiment. FIG. 6 is a cross-sectional side view of an illustrative electronic device showing how vertical slots of the type shown in FIG. 5 may be formed, according to an embodiment. FIGS. 7 and 8 are cross-sectional side views of an illustrative electronic device illustrating how a distributed capacitance of the type shown in FIG. 5 may be formed between display ground structures and an antenna resonating element, according to an embodiment. FIG. 9 is a graph of antenna power (antenna efficiency) versus frequency for an antenna of the type shown in FIGS. 5-8, according to one embodiment.DETAILED DESCRIPTIONElectronic devices, such as electronic device 10 in FIG. 1, may be provided with wireless communication circuitry. The wireless communication circuit may be used to support wireless communication in multiple wireless communication bands.Wireless communication circuitry may include one or more antennas. The antennas of wireless communication circuitry may include loop antennas, reverse F antennas, strip antennas, reverse F planar antennas, slot antennas, hybrid antennas including antenna structures of more than one type, or other suitable antennas. Conductive structures for the antennas may be formed of conductive structures of electronic devices, if desired.The conductive structures of electronic devices may include conductive housing structures. The package structures may include peripheral structures, such as peripheral conductive structures, that run around the periphery of an electronic device. The peripheral conductive structures may serve as a bezel for a planar structure such as a display, may serve as sidewall structures for a device package, may have portions that extend upwardly from an integral planar back side package (e.g., to form vertical planar sidewalls or curved sidewalls), and / or may form other package structures.Gaps may be formed in the peripheral conductive structures that divide the peripheral conductive structures into peripheral segments. One or more of the segments may be used in forming one or more antennas for the electronic device 10. Antennas may also be formed using an antenna ground plane and / or antenna resonating element formed from conductive housing structures (e.g., internal and / or external structures, substrate structures, etc.).The electronic device 10 may be a portable electronic device or other suitable electronic device. For example, the electronic device 10 may be a laptop computer, a tablet computer, a somewhat smaller device such as a wristwatch device, a decorative fob device, a headphone device, a hearing element device, or other wearable or miniature device, a hand-held device such as a mobile phone, a media playback device, or other small wearable device. The device 10 may also be a set-top box, a desktop computer, a display incorporating a computer or other processing circuitry, a display without an integrated computer, or other suitable electronic equipment.The device 10 may include a housing, such as a housing 12. The housing 12, which may sometimes be referred to as a "case", may be formed of plastic, glass, ceramic, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, portions of the housing 12 may be formed of dielectric or other low conductivity material (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, the housing 12, or at least some of the structures from which the housing 12 is constructed, may be formed from metal members.The device 10 may include a display, such as a display 14, if desired. The display 14 may be mounted on the front of the device 10.The display 14 may be a touch-sensitive screen incorporating capacitive touch electrodes or insensitive to touch. The rear side of the housing 12 (i.e. the side of the device 10 opposite the front side of the device 10) can have a planar housing wall. The rear housing wall may include slots that pass entirely through the rear housing wall, thus separating housing wall portions (and / or side wall portions) of the housing 12 from one another. The housing rear wall may include conductive portions and / or dielectric portions. If desired, the housing rear wall may include a planar metal layer covered by a thin layer or coating of dielectric material such as glass, plastic, sapphire, or ceramic. The housing 12 (e.g., the rear housing wall, the side walls, etc.) may also have shallow grooves that do not completely pass through the housing 12. The slits and grooves may be filled with plastic or other dielectric. If desired, portions of the housing 12 that have been separated from each other (e.g., by a through slot) may be connected by internal conductive structures (e.g., sheet metal or other metal pieces that bridge the slot).The display 14 may include pixels formed from light emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, liquid crystal display (LCD) components), or other suitable pixel structures. A display cover layer, such as a clear glass or plastic layer, may cover the surface of the display 14, or the outermost layer of the display 14 may be formed of a color filter layer, a thin film transistor layer, or another display layer. Buttons, such as button 24, may pass through openings in the cover layer. The cover layer can also have further openings, such as an opening for a loudspeaker connection 26.The housing 12 may include peripheral housing structures, such as structures 16. The structures 16 may extend around the periphery of the device 10 and the display 14. In configurations in which the device 10 and the display 14 have a rectangular shape with four edges, the structures 16 may be implemented using peripheral housing structures having a rectangular ring shape with four corresponding edges (for example). The peripheral structures 16 or a portion of the peripheral structures 16 may serve as a surround for the display 14 (e.g., a cosmetic seam that surrounds all four sides of the display 14 and / or helps to retain the display 14 on the device 10). The peripheral structures 16 may also form sidewall structures for the device 10 (e.g., by forming a metal band having vertical sidewalls, curved sidewalls, etc.), if desired.The peripheral housing structures 16 may be formed of a conductive material such as metal and may therefore sometimes be referred to as peripheral conductive housing structures, conductive housing structures, peripheral metal structures, or a peripheral conductive housing member (as examples). The peripheral housing structures 16 may be formed of a metal, such as stainless steel, aluminum, or other suitable materials. One, two, or more than two separate structures may be used in forming the peripheral package structures 16.It is not necessary for the peripheral housing structures 16 to have a uniform cross section. For example, the upper portion of the peripheral housing structures 16 may include an inwardly projecting lip, if desired, which helps to hold the display 14 in place. The lower portion of the peripheral housing structures 16 may also include an enlarged lip (e.g., in the plane of the rear surface of the device 10). The peripheral housing structures 16 may have substantially straight vertical sidewalls, may have sidewalls that are curved, or may have other suitable shapes. In some configurations (e.g., when the peripheral housing structures 16 serve as a surround for the display 14), the peripheral housing structures 16 may extend around the lip of the housing 12 (i.e., the peripheral housing structures 16 may cover only the edge of the housing 12 surrounding the display 14 and not the remainder of the sidewalls of the housing 12).If desired, the housing 12 may have a conductive rear surface or wall. For example, the housing 12 may be formed of a metal such as stainless steel or aluminum. The rear surface of the housing 12 may lie in a plane parallel to the display 14. In configurations for the device 10 in which the rear surface of the housing 12 is formed of metal, it may be desirable to form portions of the peripheral conductive housing structures 16 as integral portions of the housing structures that form the rear surface of the housing 12. For example, a housing rear wall of the device 10 may be formed from a planar metal structure, and portions of the peripheral housing structures 16 on the sides of the housing 12 may be formed as flat or curved vertically extending integral metal portions of the planar metal structure. Housing structures such as these may be machined from a metal block, if desired, and / or may include multiple pieces of metal that are assembled to form the housing 12. The planar rear wall of the housing 12 may include one or more, two or more, or three or more portions. The peripheral conductive housing structures 16 and / or the conductive back wall of the housing 12 may form one or more exterior surfaces of the device 10 (e.g., surfaces visible to a user of the device 10) and / or may be implemented using interior structures that do not form exterior surfaces of the device 10 (e.g., conductive housing structures that are not visible to a user of the device 10, such as conductive housing structures 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 the device 10 and / or serve to hide the structures 16 from view of the user).The display 14 may include a pixel array forming an active area AA that displays images for a user of the device 10. An inactive edge region IA, such as inactive region IA, may extend along one or more outer edges of the active region AA.The display 14 may include conductive structures such as an array of capacitive electrodes for a touch-sensitive sensor, conductive lines for pixel elements, driver circuitry, etc. The housing 12 may include internal conductive structures such as metal frame elements and a planar conductive housing element (sometimes referred to as a back plate) that spans the walls of the housing 12 (i.e., a substantially rectangular sheet formed of one or more pieces that is welded or otherwise joined between opposing sides of the element 16). The backplate may form an outer rear surface of the 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 outer surfaces of the device 10 and / or serve to hide the backplate from the user's view. The device 10 may also include conductive structures such as circuit boards, circuit board mounted components, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in the device 10, may extend, for example, under the active area AA of the display 14.Openings may be formed in regions 22 and 20 within the conductive structures of device 10 (e.g., between peripheral conductive housing structures 16 and opposing conductive ground structures, such as conductive portions of housing 12, conductive traces on a 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 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, conductive display structures, and other conductive structures in device 10 may serve as a ground plane for the antennas in device 10. The openings in regions 20 and 22 may serve as slots in open or closed slot antennas, may serve as a middle dielectric region surrounded by a conductive path of materials in a loop antenna, may serve as a space separating 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 element, or may otherwise serve as part of antenna structures formed in regions 20 and 22. If desired, the ground plane located below the active area AA of the display 14 and / or other metal structures in the device 10 may have portions that extend into portions of the ends of the device 10 (e.g., the ground may extend toward the dielectric-filled openings in the regions 20 and 22), thereby narrowing the slots in the regions 20 and 22.In general, the 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 the device 10 may be located at opposing first and second ends of an elongated device housing (e.g., at the ends 20 and 22 of the device 10 of FIG. 1 ), along one or more edges of a device housing, in the center of a device housing, at other suitable locations, or at one or more of these locations. The arrangement of Fig. 1 is for illustrative purposes only.Portions of the peripheral housing structures 16 may be provided with peripheral gap structures. For example, peripheral conductive package structures 16 may be provided with one or more columns, such as column 18 shown in FIG. 1. The gaps in the peripheral housing structures 16 may be filled with a dielectric, such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. The gaps 18 may divide the peripheral housing structures 16 into one or more peripheral conductive segments. For example, there may be two peripheral conductive segments in peripheral package structures 16 (e.g., in an array with two of the columns 18), three peripheral conductive segments (e.g., in an array with three of the columns 18), four peripheral conductive segments (e.g., in an array with four columns 18, etc.). The segments of the peripheral conductive housing structures 16 formed in this manner may form portions of antennas in the device 10.If desired, openings in the housing 12, such as grooves extending partially or fully through the housing 12, may extend across the width of the rear wall of the housing 12 and may pierce the rear wall of the housing 12 to divide the rear wall into different portions. These grooves may also extend into the peripheral housing structures 16 and may form antenna slots, gaps 18, and other structures in the device 10. A polymer or other dielectric may fill these grooves and other package openings. In some situations, housing openings forming antenna slots and other structures may be filled with a dielectric, such as air.In a typical scenario, the device 10 may include one or more upper and one or more lower antennas (for example). For example, an upper antenna may be formed at the upper end of the device 10 in the region 22. For example, a lower antenna may be formed at the lower end of device 10 in region 20. The antennas may be used separately to cover identical communication bands, overlapping communication bands, or separate communication 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 communication bands of interest. For example, device 10 may include antenna structures for supporting local area network (GPS) communication, voice and data cellular telephone communication, global positioning system (GPS) communication), or other satellite navigation system communication, Bluetooth® communication, etc.A schematic diagram showing illustrative components that may be used in the apparatus 10 of FIG. 1 is shown in FIG. 2. As shown in FIG. 2, the apparatus 10 may include control circuitry, such as the storage and processing circuitry 28. The storage and processing circuitry 28 may include a storage device, e.g., a hard disk drive memory, non-volatile memory (e.g., flash memory or other electrically programmable read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random access memory), etc. Processing circuitry in the memory and processing circuitry 28 may be used to control the operation of the device 10. This processing circuit may be based on one or more microprocessors, microcontrollers (microcontrollers), digital signal processors, application specific integrated circuits (application specific integrated circuits), etc.The storage and processing circuitry 28 may be used to execute software on the device 10, such as Internet browsing applications, VOIP phone call applications (VOIP= Vo over Internet Protocol), email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, the storage and processing circuitry 28 may be used to implement communication protocols. Communication protocols that may be implemented using the storage and processing circuitry 28 include Internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols -- sometimes referred to as WiFi® ), protocols for other short-range wireless communication links, such as the Bluetooth® protocol, mobile phone protocols, multiple-input-multiple-output (MIMO) protocols), antenna diversity protocols, etc.Input-output circuitry 30 may include input-output devices 32. The input-output devices 32 may be used to allow data to be provided to the device 10 and to allow data to be provided from the device 10 to external devices. The 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-sensitive screens, displays without touch sensor capabilities, buttons or keys, joysticks, scroll wheels, touchpads, keypads, keyboards, microphones, cameras, buttons or keys, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, position and orientation sensors (e.g., sensors such as accelerometers, gyroscopes, and compass), capacitance sensors, proximity sensors (e.g., capacitive proximity sensors, light-based proximity sensors), fingerprint sensors (e.g., a fingerprint sensor integrated into a key such as key 24 of FIG. 1, or a fingerprint sensor, The button may include the button 24 replaced), etc.The input-output circuit 30 may include wireless communication circuitry 34 for wirelessly communicating with external equipment. Wireless communication circuitry 34 may include radio frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling wireless RF signals. Wireless signals may also be transmitted using light (e.g., using infrared communication).Wireless communication circuitry 34 may include radio frequency transceiver circuitry 90 for handling various radio frequency communication bands. For example, circuitry 34 may include transceiver circuitry 36, 38, and 42. Transceiver circuitry 36 may handle 2.4 GHz and 5 GHz bands for WiFi (W(IEEE 802.11) communication and the 2.4 GHz-Bluetooth® communication band. The circuitry 34 may use cellular phone transceiver circuitry 38 to handle wireless communication in frequency ranges such as a low communication band of 700 to 960 MHz, a low mid-band of 960 to 1710 MHz, a mid-band of 1710 to 2170 MHz and a high-band of 2300 to 2700 MHz, an ultra high-band of 3400 to 3700 MHz, or other communication bands between 600 MHz and 4000 MHz, or other suitable frequencies (as examples).The circuitry 38 may handle voice data and non-voice data. If desired, wireless communication circuitry 34 may include circuitry for other short and long range wireless connections. For example, wireless communication circuitry 34 may include 60 GHz transceiver circuitry, circuitry for receiving television and radio signals, paging system transceivers, near field communication (NFC) circuitry, etc. Wireless communication circuitry 34 may include global positioning system (GPS) receiver equipment, such as GPS receiver circuitry 42, for receiving GPS signals at 1575 MHz or for handling other satellite positioning data. In WiFi® and Bluetooth® connections and other short-range wireless connections, wireless signals are typically used to communicate data over tens or hundreds of feet. In cellular telephone and other long range connections, wireless signals are typically used to transmit data over thousands of feet or miles.Wireless communication circuitry 34 may include antennas 40. Antennas 40 may be formed using any suitable antenna types. For example, antennas 40 may include antennas having resonant elements formed of loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, inverted-F planar antenna structures, helical antenna structures, dipole antenna structures, monopole antenna structures, blends of these designs, etc. Different types of antennas may be used for different bands and combinations. For example, one type of antenna may be used in forming an antenna for a local wireless connection, and another type of antenna may be used in forming an antenna for a remote wireless connection.As shown in FIG. 3, transceiver circuitry 90 in wireless circuitry 34 may be coupled to antenna structures 40 using paths such as path 92. The wireless communication circuitry 34 may be coupled to the control circuitry 28. Control circuitry 28 may be coupled to input-output devices 32. Input-output devices 32 may provide output from device 10 and receive input from sources external to device 10.To provide antenna structures, such as the one or more antennas 40, with the capability to cover communication frequencies of interest, one or more antennas 40 may be provided with circuitry, such as filter circuits (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 circuits. Capacitive structures, inductive structures, and resistor structures may also be formed of patterned metal structures (e.g., a portion of an antenna). If desired, the one or more antennas 40 may be provided with adjustable circuitry, such as tunable components 102, to tune antennas via communication bands of interest. The tunable components 102 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 an antenna ground, etc.The tunable components 102 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 generate associated distributed capacitances and inductances, solid state variable devices for generating variable capacitance and inductance values, tunable filters, or other suitable tunable structures. During operation of the device 10, the control circuitry 28 may output control signals on one or more paths, such as path 109, that adjust inductance values, capacitance values, or other parameters associated with the tunable components 102, thereby tuning the antenna structures 40 to cover desired communication bands.Path 92 may include one or more transmission lines. As an example, signal path 92 of FIG. 3 may be a transmission line having a positive signal conductor, such as line 94, and a ground signal conductor, such as line 96. The lines 94 and 96 may form portions of a coaxial cable, a strip line transmission line, or a microstrip transmission line (as examples). A matching network (e.g., a matching network formed using the components 102) may include components such as inductors, resistors, and capacitors used in matching the impedance of the antenna(s) 40 to the impedance of the transmission line 92. The matching network components may be provided as discrete components (e.g., surface mount technology components) or from package structures, circuit board structures, traces on plastic substrates, etc. Components such as these may also be used in forming filter circuits in the antenna(s) 40, and may be tunable and / or fixed components.The transmission line 92 may be coupled to antenna feed structures associated with the antenna structures 40. As an example, the antenna structures 40 may form a reverse F antenna, slot antenna, a reverse F slot hybrid antenna, or other antennas having an antenna feed 112 with a positive antenna feed terminal, such as terminal 98, and a ground antenna feed terminal, such as ground antenna feed terminal 100. The positive transmission line conductor 94 may be coupled to the positive antenna feed terminal 98, and the ground transmission line conductor 96 may be coupled to the ground antenna feed terminal 100. Other types of antenna feed arrangements may be used if desired. For example, the antenna structures 40 may be supplied using multiple leads. The illustrative lead configuration of FIG. 3 is for illustrative purposes only. The control circuitry 28 may receive information from a proximity sensor (see, e.g..Sensors 32 of FIG. 2 ) use 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 sensor, information about a usage scenario of the device 10, information about whether audio is played back via the speaker 26, information from one or more antenna impedance sensors, and / or other information to determine when the antenna(s) 40 is impaired by the presence of adjacent external objects or otherwise needs to be tuned. In response, control circuitry 28 may adjust an adjustable inductor, capacitor, switch, or other tunable components 102 to ensure that antenna structures 40 operate as desired. Adjustments to the components 102 may also be made to increase the range of the antenna structures 40 (e.g., to cover the desired communication bands that extend over a range of frequencies greater than that which the antenna structures 40 would cover without tuning).The presence or absence of external objects, such as a user's hand, may affect antenna loading and thus antenna performance. The antenna loading may vary depending on the manner in which the device 10 is held. For example, antenna loading and thus antenna performance may be compromised in one manner when a user holds device 10 in the user's right hand, and otherwise compromised when a user holds device 10 in the user's left hand. Additionally, antenna loading may be compromised in one way when a user holds device 10 to the user's head, and in another way when the user holds device 10 away from the user's head. To accommodate various loading scenarios, the device 10 may use sensor data, antenna measurements, information about the use scenario or operating state of the device 10, and / or other data from the input-output circuitry 32 to monitor the presence of an antenna load (e.g., the presence of a user's hand, the user's head, or other external object). The device 10 (e.g., control circuitry 28) may then adjust the adjustable components 102 in the antenna 40 to compensate for the load.Antennas 40 may include slot antenna structures, reverse F antenna structures (e.g., planar and non-planar reverse F antenna structures), loop antenna structures, combinations of these, or other antenna structures.An illustrative inverted-F antenna structure is shown in FIG. 4. As shown in FIG. 4, the inverted-F antenna structure 40 (sometimes referred to herein as antenna 40 or inverted-F antenna 40) may include a resonant element of the inverted-F antenna such as the antenna resonant element 106 and an antenna ground (ground plane) such as the antenna ground 103. Antenna resonating element 106 may have a main resonating element arm, such as arm 108. The length of the arm 108 may be selected such that the antenna 40 resonate at desired operating frequencies. For example, the length of arm 108 (or a branch of arm 108) may be one quarter of a wavelength at a desired operating frequency for antenna 40. The antenna structure 40 may also exhibit resonances at harmonic frequencies. If desired, slot antenna structures or other antenna structures may be incorporated into a reverse F antenna such as antenna 40 of FIG. 4 (e.g., to improve antenna response in one or more communication bands). As an example, a slot antenna structure may be formed between the arm 108 or other portions of the resonant element 106 and the ground 103. In these scenarios, antenna 40 may include both a slot antenna and reverse F antenna structures, and may sometimes be referred to as a reverse F and slot hybrid antenna.The arm 108 may be separated from the ground 103 by a dielectric filled opening, such as the dielectric gap 101. Antenna ground 103 may be formed from housing structures, such as a conductive backing plate, printed circuit traces, metal portions of electronic components, conductive portions of display 14, and / or other conductive ground structures. The gap 101 may be formed by air, plastic, and other dielectric materials.The main resonating element arm 108 may be coupled to the ground 103 through a return path 110. An antenna feed 112 may include the positive antenna feed terminal 98 and the ground antenna feed terminal 100, and may be parallel to the return path 110 between the arm 108 and the ground 103. If desired, inverted-F antenna structures, such as the illustrative antenna structure 40 of FIG. 4, may include more than a single resonating element arm branch (e.g., to generate multiple frequency resonances to support operation in multiple communication bands) or may include other antenna structures (e.g., parasitic antenna resonating elements, tunable components to support antenna tuning, etc.). The arm 108 may have other shapes and may follow any desired path (e.g., curved and / or straight segment paths), if desired.If desired, the antenna 40 may include one or more adjustable circuits (e.g., the tunable components 102 of FIG. 3 ) coupled to the antenna resonating element structures 106, such as the arm 108. As shown in FIG. 4, tunable components 102, such as adjustable coil 114, may be coupled between antenna resonating element arm structures in antenna 40, such as arm 108 and antenna ground 103 (i.e., adjustable coil 114 may bridge gap 101). Adjustable inductor 114 may exhibit an inductance value that is adjusted in response to control signals 116 provided to adjustable inductor 114 from control circuitry 28.An upper interior view of an illustrative portion of the device 10 including antennas is shown in FIG. 5. As shown in FIG. 5, device 10 may include peripheral conductive housing structures, such as peripheral conductive housing structures 16. The peripheral conductive housing structures 16 may be divided by dielectrically filled peripheral gaps (e.g., plastic gaps) 18, such as a first gap 18- 1 and a second gap 18- 2. The resonating element for antenna 40 may include a reverse F antenna resonating element arm, such as arm 108, formed from a segment of peripheral conductive housing structures 16 that extend between gaps 18- 1 and 18- 2. Air and / or another dielectric may fill the slot 101 between the arm 108 and the display ground structures 104. If desired, the aperture 101 may be configured to form a slot antenna resonant element structure that contributes to the overall performance of the antenna. The display ground structures 104 may form portions of the antenna ground 103 (FIG. 4 ). Additional portions of the antenna ground may be formed from conductive housing structures, electrical device components in the device 10, printed circuit board traces, conductive strips such as strips of wire and metal foil, or other conductive structures. In a suitable arrangement, conductive portions of the display 14 (FIG. 1 ) (e.g., conductive portions of a display panel, a conductive plate for supporting the display panel, and / or a leadframe for supporting the conductive plate and / or the display panel) form display ground structures 104. The display ground structures 104 may be coupled to conductive portions of the housing 12 (e.g., portions of a back wall of the housing 12 and portions of peripheral conductive housing structures 16 separated from the arm 108 by peripheral gaps 18).The positive transmission line conductor 94 and the ground transmission line conductor 96 of the transmission line 92 may be coupled between the transceiver circuitry 90 and the antenna feed 112. The positive antenna feed terminal 98 of the feed 112 may be coupled to the arm 108. The ground antenna feed terminal 100 of the feed 112 may be coupled to conductive display structures 104. Transceiver circuitry 90 (e.g., remote wireless transceiver circuitry 38, local wireless transceiver circuitry 36, and / or GPS receiver circuitry 42 in FIG. 2 ) may receive radio frequency signals in frequency ranges such as a low communication band of 700 to 960 MHz, a low midband of 960 to 1710 MHz, a midband of 1710 to 2170 MHz, and a high band of 2300 to 2700 MHz, an ultra high band of 3400 to 3700 MHz, 2.4 GHz, and 5 GHz bands for WiFi® (IEEE 802.11) communication, and / or a 1575 MHz GPS band, using antenna 40 and feeder 112.Antenna feed 112 may be coupled via slot 101 at a location along conductive display structures 104 that is within a distributed capacitance region 230. In the distributed capacitance region, the conductive display structures 104 may be separated from the peripheral conductive structures 16 by the distance 238. The distributed capacitance region 230 may have any width 272. For example, the distance 238 and width 272 may be selected to form a desired distributed capacitance between the display conductive structures 104 and peripheral conductive housing structures 16 around the lead 112. For example, the distributed capacitance of region 230 may be directly proportional to width 272 and inversely proportional to distance 238. The distributed capacitance and corresponding dimensions 272 and 238 may be selected to ensure that antenna 40 is impedance matched to transmission line 92, for example. Thus, the distributed capacitance region 230 may sometimes be referred to herein as a distributed capacitor 230 (e.g., distributed impedance matching capacitor 230) or distributed capacitance 230 formed by the edge of the display ground structures 104 and the peripheral conductive structures 16 (e.g., within the width 272). The distributed capacitance region 230 may be surrounded along axis X of FIG. 5 by two regions in which the display ground structures 104 are separated from peripheral conductive package structures 16 by the distance 232 which is greater than the distance 238 if desired. The portion of the display ground structures 104 that extend closer to the peripheral conductive housing structures 16 may sometimes be referred to as ground plate extension 266.In the example of FIG. 5, the antenna feed 112 is coupled via the slot 101 at a location along the conductive display structures 104 where the conductive display structures 104 are separated from peripheral conductive housing structures 16 by the distance 238. For example, the lead 112 may be coupled via the slot 101 within the distributed capacitance region 230 such that some of the distributed capacitance is formed around the lead 112 (e.g., a portion of the distributed capacitance is located on both sides of the lead). Also in the example of FIG. 5, the display conductive structures 104 are separated from peripheral conductive housing structures 16 by a uniform distance 238 in the distributed capacitance region 230. These examples are illustrative only. Generally, the display conductive structures 104 may be separated from the peripheral conductive housing structures 16 by any distance or distances in the distributed capacitance region 230 to form any distributed impedance matching capacitance between the display ground structures 104 and the peripheral conductive housing structures 16 around the lead 112. For example, if desired, the display ground structures 104 may be separated from peripheral conductive housing structures 16 by an even distance in the distributed capacitance region 230 or by two or more different distances in the distributed capacitance region 230. In another suitable arrangement, antenna feed 112 may be coupled via slot 101 at other desired locations (e.g., at a location in the distributed capacitance region where display ground structures 104 and peripheral conductive structures 16 are separated by a distance other than distance 238, at a location outside the distributed capacitance region where display ground structures 104 and peripheral conductive structures 16 are separated by distance 232). The location of the antenna feed 112 may also be matched to another impedance matching antenna 40 with the transmission line 92.Including the distributed capacitance in the region 230 may allow an additional component, such as a surface mount technique capacitor, to be omitted, thereby saving space within the electronic device. In addition, forming the distributed impedance matching capacitor between peripheral conductive structures 16 and conductive display structures 104 may improve antenna efficiency over a wider frequency range than when a surface mount technique capacitor is coupled between peripheral conductive structures 16 and conductive display structures 104.The conductive display structures 104 may have any shape within the device 10. For example, a lower edge of the conductive display structures 104 may be aligned with the gap 18- 1 in peripheral conductive housing structures 16 (e.g., the upper or lower edge of the gap 18- 1 may be aligned with the edge of the conductive display structures 104 defining the slot 101 adjacent the gap 18- 1). This example is illustrative only. If desired, as shown in FIG. 5, the conductive display structures 104 may include a vertical slot, such as slot 162, adjacent to the slot 18- 1 that extends across the edges of the slot 18- 1 (e.g., along the Y-axis of FIG. 5 ). Similarly, the lower edge of the conductive display structures 104 may be aligned with the gap 18- 2 (e.g., the upper or lower edge of the gap 18- 2 may be aligned with the edge of the conductive display structures 104 defining the slot 101 adjacent to the gap 18- 2) or may extend across the edges of the gap 18- 2.As shown in FIG. 5, the vertical slot 162 may extend beyond the top edge (e.g., top edge 174) of the slot 18- 1 (e.g., in the direction of the Y-axis of FIG. 5 ) adjacent the slot 18- 1. For example, the slot 162 may have two edges defined by display ground structures 104 and an edge defined by peripheral conductive structures 16. The slot 162 may have an open end defined by an open end of the slot 101 at the gap 18- 1. The slot 162 may have a width 176 separating the display ground structures 104 from the portion of the peripheral conductive structures 16 above the gap 18- 1 (e.g., in the direction of the X-axis of FIG. 5 ). Because the portion of the peripheral conductive structures 16 over the gap 18- 1 is shorted to indicate ground structures 104 (and thus forms part of the antenna ground for the antenna structures 40), the slot 162 can effectively form an open slot with three sides defined by the antenna ground for the antenna structures 40. The slot 162 may have any width (e.g., about 2 millimeters, less than 4 millimeters, less than 3 millimeters, less than 2 millimeters, less than 1 millimeter, more than 0.5 millimeters, more than 1.5 millimeters, more than 2.5 millimeters, 1 to 3 millimeters, etc.). The slot 162 may have an elongated length 178 (e.g., perpendicular to the width 176). The slot 162 may have any length (e.g., 10 to 15 millimeters, more than 5 millimeters, more than 10 millimeters, more than 15 millimeters, more than 30 millimeters, less than 30 millimeters, less than 20 millimeters, less than 15 millimeters, less than 10 millimeters, between 5 and 20 millimeters, etc.).The electronic device 10 may be characterized by the longitudinal axis 282. The length 178 may extend parallel to the longitudinal axis 282 (e.g., the Y-axis of FIG. 5 ). If desired, the portions of slot 162 may contribute slot antenna resonances to antenna 40 in one or more frequency bands. For example, the length and width of the slot 162 (e.g., the perimeter of the slot 162) may be selected such that the antenna 40 resonate at desired operating frequencies. If desired, the total length of slots 101 and 162 may be selected so that antenna 40 resonate at desired operating frequencies.If desired, the display ground structures 104 may include an additional vertical slot 182 adjacent to the gap 18- 2 that extends beyond the top edge (e.g., the top edge 184) of the gap 18- 2 (e.g., in the direction of the Y-axis of FIG. 5 ). For example, slot 182 may have two edges defined by display ground structures 104 and one edge defined by peripheral conductive structures 16. Slot 182 may have an open end defined by an open end of slot 101 at gap 18- 2. The slot 182 may have a width 186 separating the display ground structures 104 from the portion of the peripheral conductive structures 16 above the gap 18- 1 (e.g., in the direction of the X-axis of FIG. 5 ). Because the portion of the peripheral conductive structures 16 over the gap 18- 2 is shorted to indicate ground structures 104 (and thus forms part of the antenna ground for the antenna structures 40), the slot 182 may effectively form an open slot with three sides defined by the antenna ground for the antenna structures 40. The slot 182 may have any width (e.g., about 2 millimeters, less than 4 millimeters, less than 3 millimeters, less than 2 millimeters, less than 1 millimeter, more than 0.5 millimeters, more than 1.5 millimeters, more than 2.5 millimeters, 1 to 3 millimeters, etc.). The slot 182 may have an elongated length 188 (e.g., perpendicular to the width 186). The slot 182 may have any length (e.g., 10 to 15 millimeters, more than 5 millimeters, more than 10 millimeters, more than 15 millimeters, more than 30 millimeters, less than 30 millimeters, less than 20 millimeters, less than 15 millimeters, less than 10 millimeters, between 5 and 20 millimeters, etc.).The length 188 may extend parallel to the longitudinal axis 282 (e.g., the Y-axis of FIG. 5 ). If desired, the portions of slot 182 may contribute slot antenna resonances to antenna 40 in one or more frequency bands. For example, the length and width of slot 182 may be selected such that antenna 40 resonate at desired operating frequencies. If desired, the total length of slots 101 and 182 may be selected so that antenna 40 resonate at desired operating frequencies. If desired, the total length of slots 101, 162 and 182 may be selected so that antenna 40 resonate at desired operating frequencies.A return path, such as path 110 of FIG. 4, may be formed by a fixed conductive path bridging slot 101 and / or one or more adjustable components, such as adjustable components 202 and / or 208 as shown in FIG. 5 (e.g., adjustable components, such as tuning components 102 of FIG. 3 ). Adjustable components 202 and 208 may sometimes be referred to herein as tuning components, tunable components, tuning circuits, tunable circuits, adjustable components, or adjustable tuning components.The adjustable component 202 may bridge the slot 101 at a first location along the slot 101 (e.g., the component 202 may be coupled between the terminal 206 on the display ground structures 104 or another component of the antenna ground 103 (FIG. 4 ) and the terminal 204 on the peripheral conductive structures 16). The adjustable component 208 may bridge the slot 101 at a second location along the slot 101 (e.g., the component 208 may be coupled between the terminal 212 on the display ground structures 104 and the terminal 210 on the peripheral conductive structures 16). The ground antenna feed terminal 100 may be disposed between the terminal 206 and the terminal 212 on the display ground structures 104. The positive antenna feed terminal 98 may be disposed between the terminal 204 and the terminal 210 on the peripheral conductive structures 16. The terminal 212 may be closer to the ground antenna feed terminal 100 than the terminal 206. The terminal 210 may be closer to the positive antenna feed terminal 98 than the terminal 204. The terminals 206 and 212 may be formed on portions of the display ground structures 104 that are separated from the peripheral conductive housing structures 16 by the distance 232.If desired, cut-out areas may be included in additional portions of antenna ground 103 (FIG. 4 ) (e.g., a conductive portion of housing 12) to accommodate additional components (e.g., an additional antenna). In embodiments where the antenna ground includes multiple layers (e.g., both a conductive layer of the housing 12 and conductive ground portions 104), the cutout regions may be formed only in a subset of the layers. For example, the cutout may be formed only in the conductive layer of the housing 12 and not in the display ground structures 104.Components 202 and 208 may include switches coupled to fixed components, such as coils for providing adjustable amounts of inductance or an open circuit between display ground structures 104 and peripheral conductive structures 16. components 202 and 208 may also include fixed components not coupled to switches or a combination of components coupled to switches and components not coupled to switches. These examples are for illustrative purposes only, and, in general, components 202 and 208 may include other components such as adjustable return path switches, switches coupled to capacitors, or any other components (e.g., resistors, capacitors, inductors, and / or inductors arranged in any desired manner).The components 202 and 208 may be adjusted based on the operating environment of the electronic device. For example, a tuning mode for antenna 40 may be selected based on the presence or absence of external objects, such as a hand of the user or other body part near antenna 40 and / or based on required communication bands. The components 202 and 208 may provide flexibility to the antenna 40 to accommodate different loading conditions (e.g., different loading conditions that may occur due to the presence of a hand of the user or other external object at different different portions of the device 10 adjacent to different corresponding portions of the antenna 40).The components 202 and 208 may be formed between peripheral conductive housing structures 16 and display ground structures 104 using any desired structures. For example, the components 202 and 208 may each be formed on a respective printed circuit board, such as a flexible printed circuit board, coupled between peripheral conductive housing structures 16 and the display ground structures 104.The frequency response of the antenna 40 may be dependent on the tuning mode of the adjustable components 202 and 208. For example, in a first tuning mode, the adjustable component 202 may form an open circuit between the antenna resonating element arm 108 and the display ground structures 104, while the adjustable component 208 may selectively couple one or more coils between the antenna resonating element arm 108 and the display ground structures 104 to tune the antenna 40. In the first tuning mode, the resonance of the antenna 40 in the low band LB (e.g., from 700 MHz to 960 MHz or other suitable frequency range) may be associated with the distance along peripheral conductive structures 16 between the feed line 112 of FIG. 5 and the gap 18- 1, for example. FIG. 5 is a front view of the device 10 such that the gap 18- 1 of FIG. 5 lies on the left edge of the device 10 when the device 10 is viewed from the front (e.g., the side of the device 10 on which the display 14 is formed in FIG. 1 ) and lies on the right edge of the device 10 when the device 10 is viewed from the rear. The resonance of antenna 40 in mid-band MB (e.g., 1710 MHz to 2170 MHz) may be associated with the distance along peripheral conductive structures 16 between feed line 112 and gap 18- 2, for example. Antenna performance in the mid-band MB may also be supported by the slot 182 in the display ground structures 104. Antenna power in high band HB (e.g., 2300 MHz to 2700 MHz) may be supported by slot 162 in display ground structures 104 and / or by a harmonic mode of resonance supported by antenna arm 108.In a second tuning mode, the adjustable component 208 may form an open circuit between the antenna resonating element arm 108 and the display ground structures 104 to tune the antenna, while the adjustable component 202 may selectively couple one or more coils between the antenna resonating element arm 108 and the display ground structures 104 to tune the antenna 40. For example, in the second tuning mode, the resonance of the antenna 40 in the low band LB may be associated with the distance along peripheral conductive structures 16 between the position of the component 202 (i.e., port 204) of FIG. 5 and the gap 18- 2. The resonance of the antenna 40 in the mid-band MB may be associated with the distance along peripheral conductive structures 16 between the position of the component 202 (i.e., port 204) and the gap 18- 1, for example. Antenna performance in high band HB may also be supported by slot 162 in display ground structures 104.In a third tuning mode, the adjustable components 202 and 208 may both selectively couple one or more coils between the antenna resonating element arm 108 and the display ground structures 104 to tune the antenna 40. In the third tuning mode, the resonance of antenna 40 in mid-band MB and high-band HB may be associated with a loop that includes portions of peripheral conductive structures 16 (e.g., the portion of peripheral conductive structures 16 between terminal 204 of component 202 and terminal 210 of component 208), component 202, display ground structures 104, and component 208.Antennas 40 may be configured to handle different frequency bands in each tuning mode. For example, in the first tuning mode, the antenna 40 may be configured to perform communication in a low band, a medium band, and a high band. In the second tuning mode of the antenna 40, performing the communication in the low band, medium band, and high band may also be configured. However, the first and second tuning modes may compensate for antenna loading by an external device such as a hand of the user in different ways. For example, in the first tuning mode, the antenna 40 may be configured to operate with a relatively high antenna efficiency when the device 10 is held by a user from the right hand and a relatively low antenna efficiency when the device 10 is held by a user from the left hand, while in the second tuning mode, the antenna 40 may be configured to operate with a relatively high antenna efficiency when the device 10 is held by the left hand of a user and with a relatively low antenna efficiency when the device 10 is held by the right hand of a user. In other words, in the first and second tuning modes, the antenna 40 may perform low-band, medium-band, and high-band wireless communications, but may be sensitive to certain operating conditions, for example which hand a user uses to hold the device 10.In general, antenna 40 may be more susceptible to changing load conditions and detuning when operating in the low band than when operating in the medium or high band. In the third tuning mode, the antenna 40 may be configured to operate at a relatively high efficiency regardless of which hand a user uses to hold the device 10 (e.g., the antenna 40 may be compliant or may conform to the user's handiness). However, when placed in the third tuning mode, the antenna 40 may only cover a subset of the frequency bands that the antenna 40 may cover in the first and second tuning modes. For example, in the third tuning mode, the antenna 40 may cover the medium band and the high band without covering the low band.FIG. 6 is a cross-sectional side view of the electronic device 10 (e.g., as taken along line 260 in FIG. 5 ). As shown in FIG. 6, the display 14 for the electronic device 10 may include a display cover layer, such as the display cover layer 302, which covers the display panel 304. The display panel 304 (sometimes referred to as a display module) may be any type of display panel and may include pixels formed from light emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, liquid crystal display (LCD) components), or other suitable pixel structures. The lateral area of the display panel 304 may determine, for example, the size of the active area AA (FIG. 1 ) of the display 14. The display panel 304 may include active light emitting components, touch sensor components (e.g., touch sensor electrodes), force sensor components, and / or other active components. The display cover layer 302 may be a layer of clear glass, plastic, or other dielectric covering the light emitting surface of the underlying display panel. In another suitable arrangement, the display cap layer 302 may be the outermost layer of the display panel 304 (e.g., the layer 302 may be a color filter layer, thin film transistor layer, or other display layer). Buttons may pass through openings in the top layer 302 (see button 24 in FIG. 1 ). The cover layer may also include other openings, such as an opening for a speaker port (see speaker port 26 in FIG. 1 ), openings for a sensor (e.g., sensor 248), or openings for any other desired electronic component.The display panel 304 may be supported within the electronic device 10 by a conductive display support plate (sometimes referred to as a center plate or display plate) such as the display plate 306. The conductive display frame 308 may hold the display panel 306 and / or the display panel 304 in place on the housing 12. For example, the display frame 308 may be annular and include a portion that extends around the perimeter of the display panel 304 and surrounds a central opening. The display plate 306 and the display frame 308 may both be formed of conductive material (e.g., metal). The display panel 306 and the display frame 308 may be in direct contact such that the display panel 306 and the display frame 308 are electrically connected. If desired, the display plate 306 and the display frame 308 may be integrally formed (e.g., from the same piece of metal). The arrangement of FIG. 6 may allow the inactive region IA (FIG. 1 ) of the display 14 to be very thin.A plastic frame 310 may be molded around the display frame 308. The plastic frame 310 may also be annular (similar to the display frame 308). The electronic device 10 may have a rectangular perimeter with top and bottom edges coupled together by left and right edges. The plastic frame 310 may extend around the rectangular perimeter of the electronic device 10. The plastic frame 310 may be formed of molded plastic or any other desired dielectric material and may serve to mount the frame 308, and thus the plate 306 and the panel 304, to peripheral conductive housing structures 16. The leadframe 308, the conductive plate 306, and conductive portions of the panel 304 (e.g., conductive electrodes, pixel circuitry, ground layers, ferrite layers, shield layers, etc.) may form display ground structures 104 for the antenna 40 (FIG. 5 ).The peripheral conductive housing structure 16 may include integral ledge portions 326. The integral ledge portions 326 may extend away from the peripheral conductive housing structure 16 towards the interior of the electronic device 10. The integral ledge portions 326 may be used to mount various components within the electronic device 10, if desired. For example, in an illustrative embodiment, the plastic frame 310 may be supported by a ledge portion 326 of the peripheral conductive housing structure 16.As shown in FIG. 6, the package 12 (FIG. 1 ) may include dielectric package portions such as the dielectric layer 324 and conductive package portions such as the conductive layer 320 (sometimes referred to herein as a conductive package wall 320). If desired, the dielectric layer 324 may be formed below the layer 320 such that the layer 324 forms an outer surface of the device 10 (e.g., to thereby protect the layer 320 from wear and / or to hide the layer 320 from the view of the user). The conductive housing portion 320 may be electrically connected to the display ground structures. For example, the conductive housing portion 320 may be a conductive support plate or wall (e.g., a conductive back plate or housing back wall) for the device 10. The conductive housing portion 320 may extend across the width of the device 10 (e.g., between two opposing sidewalls formed by peripheral housing structures 16), if desired. If desired, the conductive housing portion 320 and the opposing sidewalls of the device 10 may be formed from a single integral piece of metal, or the portion 320 may be otherwise shorted to the opposing sidewalls of the device 10. The dielectric layer 324 may be, for example, a thin glass, sapphire, ceramic or sapphire layer or other dielectric coating. If desired, in another suitable arrangement, the conductive layer 324 may be omitted.At each ground terminal within the device (e.g., terminals 206, 212, 100 in FIG. 5 ), different components of the device ground may be electrically connected such that the conductive structures (e.g., conductive display structures 104 in FIG. 5 ) disposed closest to a resonating element arm portion of the peripheral conductive structures 16 are maintained at ground potential and form part of the antenna ground 103 (FIG. 4 ). In a suitable arrangement, the antenna ground includes both display ground structures (e.g., conductive portions of display panel 304, conductive plate 306, and / or leadframe 308), as well as conductive portions of housing 12 (e.g., portions of a housing back wall 12 such as conductive back plate 320, and portions of peripheral conductive housing structures 16 separated from arm 108 by peripheral gaps 18). Vertical conductive structures (e.g., a clip, clip, spring, pin, screw, solder, weld, conductive adhesive, wire, metal strip, or a combination thereof) may couple conductive portions of the housing 12 (e.g., a conductive back plate) to the display ground structures 104 at the terminals 206, 212, and / or 100 in FIG. 5. For example, when the conductive structures near the resonating element arm 108 (FIG. 5 ), such as conductive display structures, are maintained at ground potential, they may serve to optimize the antenna efficiency of the antenna structures 40. In a suitable arrangement, ground terminals 206, 212, and / or 100 (FIG. 5 ) may include a conductive structure, such as a spring, that electrically connects the conductive back plate to conductive display structures.As shown in FIG. 6, the slot 162 may be formed between the peripheral conductive housing structures 16 and the lead frame 308 (which forms a portion of the display ground structures 104). Similarly, the slot 182 may be formed between the peripheral conductive housing structures 16 and the lead frame 308. In this example, the width 176 (FIG. 5 ) of the slot 162 is defined by the distance between the leadframe 308 and the peripheral conductive housing structures 16 (e.g., on a side of the electronic device adjacent to the dielectric-filled gap 18- 1). The width 186 (FIG. 5 ) of the slot 182 is defined by the distance between the lead frame 308 and the peripheral conductive housing structures 16 (e.g., on a side of the electronic device adjacent to the dielectric-filled gap 18- 2). The conductive package layer 320 may also form a portion of the antenna ground 103 (FIG. 4 ). Below slot 162, conductive package layer 320 may be separated from peripheral conductive package structures 16 by a distance 332 greater than or equal to the width of slot 162. Below slot 182, conductive package layer 320 may be separated from peripheral conductive package structures 16 by a distance 334 greater than or equal to the width of slot 182. The example of FIG. 6 is illustrative only, and other arrangements may be used to form the slots 162 and 182 in the display ground structures 104.FIGS. 7 and 8 are cross-sectional side views illustrating how a distributed capacitance of the type shown in FIG. 5 may be formed between display ground structures and an antenna resonating element. FIG. 7 is a cross-sectional side view taken along line 262 in FIG. 5, while FIG. 8 is a cross-sectional side view taken along line 264 in FIG. 5. In FIG. 7 (showing a portion of the display ground structures 104 and the peripheral conductive structures that are not in the distributed capacitance region), the display conductive frame 308 is separated from the peripheral conductive housing structures 16 by the distance 232. In FIG. 8 (showing a portion of the display ground structures 104 and peripheral conductive structures located in the distributed capacitance region), the display conductive frame 308 is separated from the peripheral conductive housing structures 16 by a distance 238 that is less than the distance 232. FIGS. 7 and 8 show how the leadframe 308 is extended towards the peripheral conductive package structures 16 in the distributed capacitance region 230 (FIG. 5 ). The portion of the display frame 308 that extends closer to the peripheral conductive structures 16 in the distributed capacity region may sometimes be referred to as a display frame extension or an extended portion of the display frame. The display frame extension and the peripheral conductive structures 16 may form a desired distributed capacitance between the display ground structures 104 and the peripheral conductive package structures 16.As shown in FIG. 7, the conductive display frame 308 may be electrically connected to a radio frequency shield 312 through a conductive pattern 309. The conductive structure 309 may directly contact both the display frame 308 and the radio frequency shield 312. The conductive structure 309 may be a spring or any other desired structure (e.g., a clip, clip, spring, pin, screw, solder, weld, conductive adhesive, wire, metal strip, or a combination thereof). Alternatively, the display frame 308 may directly contact the radio frequency shield 312 without an intervening structure (and the conductive structure 309 may be omitted). Fasteners 328 and 330 may attach the high-frequency shield 312 and the conductive case layer 320 to each other. The fasteners 328 and 330 may be conductive to also electrically connect the components. For example, the fasteners 328 and / or 330 may electrically connect the radio frequency shield 312 to the conductive housing layer 320 such that the radio frequency shield 312 forms a portion of the antenna ground. The fastener 330 may be a screw and the fastener 328 may be a screw protrusion that receives the screw 330. However, this example is illustrative only and generally, fasteners 328 and 330 may each be a clip, clip, spring, pin, screw, solder, weld, conductive adhesive, wire, metal strip, or a combination thereof.The radio-frequency shield 312 may therefore electrically connect different portions of the antenna ground (e.g., the radio-frequency shield 312 may electrically connect the conductive package layer 320 to the leadframe 308). Additional components within the electronic device (e.g., customizable component 202 in FIG. 5 ) may be coupled to the radio frequency shield 312, if desired.The high-frequency shield 312 may also shield components in the electronic device 10 from interference. For example, in an illustrative arrangement, an additional n-way below the high-frequency shield 312 (e.g., in a cut-out region of the antenna ground) may be formed. Forming an additional antenna below the radio-frequency shield 312 may result in the additional antenna being shielded from radio-frequency signals generated by other components within the electronic device 10 (e.g., radio-frequency signals arising on the other side of the radio-frequency shield).As shown in FIG. 7, the electronic device 10 may also include a flexible printed circuit 342 that transmits signals for the display 14.For example, the flexible printed circuit 342 may be coupled to a thin film transistor layer of the display panel 304. The flexible printed circuit 342 may also be coupled to an additional flexible printed circuit or a rigid printed circuit board (e.g., a main logic board). The lead frame 308, the plastic frame 310, the display panel 304, and / or the display panel 306 may receive a flexible printed circuit 342.As shown in FIG. 8, a substrate such as the printed circuit 250 may also be included in the electronic device 10. The printed circuit 250 may be a rigid printed circuit board (e.g., a printed circuit board formed of fiberglass-filled epoxy or other rigid circuit board material) or a flexible printed circuit (e.g., a flexible printed circuit formed of a polyimide layer or other flexible polymer layer). The printed circuit 250 may include antenna traces, such as an antenna resonating element (e.g., for an additional antenna in a cutout area in antenna ground), transmission line structures (e.g., transmission line structures for the transmission line 92 of FIG. 5 ), surface mount technique components, terminals for an antenna feed line (e.g., positive feed line terminal 98 or ground feed line terminal 100 of FIG. 5 ), or other arbitrary traces or components. A conductive fastener, such as a screw 264 or other desired conductive structure (e.g., a clip, clip, spring, pin, screw, solder, weld, conductive adhesive, wire, metal strip, or a combination thereof) may electrically connect and / or mechanically attach the flexible circuit board 250 to the conductive housing layer 320. A screw protrusion or threaded opening in the conductive housing layer 320 may receive the screw 264. The printed circuit board 250 may be coupled to an additional printed circuit including transceiver circuitry (e.g., transceiver circuitry 90 in FIG. 5 ), if desired.FIG. 9 is a graph of antenna efficiency versus frequency for an illustrative antenna of the type shown in FIGS. 5-8. As shown in FIG. 9, antenna 40 (FIG. 5) may have resonances between frequencies F- 1 and F 2. The frequencies F 1 and F 2 may be any frequencies (e.g., 1710 MHz and 2700 MHz). The antenna 40 (FIG. 5 ) may have antenna efficiency characterized by a curve 402 between frequencies F 1 and F 2 when there is a distributed capacitance (e.g., in the region 230 of FIG. 5 ) formed between the display ground structures 104 (FIG. 5 ) and the peripheral conductive housing structures 16 (FIG. 5 ). Curve 404 denotes antenna efficiency in an arrangement where the distributed capacitance range of FIG. 5 is omitted and a surface mount technique capacitor is instead coupled between the peripheral conductive structures and the display ground structures. As shown in FIG. 9, the distributed capacitance formed between the display ground structures 104 and the peripheral conductive housing structures 16 in FIG. 5 may improve antenna efficiency over a wider frequency range than when a discrete surface mount technique capacitor is coupled between the display ground structures and the peripheral conductive housing structures. This example is illustrative only and, if desired, the curves may have any shapes in any bands. If desired, the antenna 40 may have resonances in any frequency bands (e.g., a low band of 700 to 960 MHz, a low mid-band of 960 to 1710 MHz, a mid-band of 1710 to 2170 MHz, high-band of 2300 to 2700 MHz, an ultra high-band of 3400 to 3700 MHz, etc.).According to one embodiment, an electronic device is provided that includes a housing having peripheral conductive structures, a display in the housing, a lead frame for display, an antenna resonating element arm for an antenna, the antenna resonating element arm formed from a segment of the peripheral conductive structures, and an antenna ground for display that includes the lead frame for display.According to another embodiment, the lead frame includes a first portion separated from the antenna resonating element arm by a first distance and a second portion separated from the antenna resonating element arm by a second distance less than the first distance, and the second portion is configured to form a distributed capacitance with the antenna resonating element arm.According to another embodiment, the electronic device includes an antenna feed for the antenna, the antenna feed coupled between the second portion of the lead frame and the antenna resonating element arm.According to another embodiment, the electronic device includes a conductive display plate coupled to the leadframe, wherein the antenna ground includes the conductive display plate.According to another embodiment, the lead frame has a rectangular perimeter with top and bottom edges coupled together by left and right edges and a central opening surrounded by the top, bottom, left and right edges.According to another embodiment, the segment of the peripheral conductive structures is a first segment, wherein the electronic device includes a first dielectrically filled gap in the peripheral conductive structures separating the first segment and a second segment of the peripheral conductive structures and a second dielectrically filled gap in the peripheral conductive structures separating the first segment from a third segment of the peripheral conductive structures.According to another embodiment, the antenna ground includes the second and third segments of the peripheral conductive structures and a planar conductive layer extending between the second and third segments of the peripheral conductive structures.According to another embodiment, the electronic device includes a conductive structure that electrically couples the planar conductive layer to the conductive frame.According to another embodiment, the antenna ground includes a first vertical slot extending beyond an edge of the first dielectric filled gap, and wherein the first vertical slot has edges defined by the leadframe and the second segment of the peripheral conductive structures.According to another embodiment, the antenna ground includes a second vertical slot extending beyond an edge of the second dielectric filled gap, and wherein the second vertical slot has edges defined by the leadframe and the third segment of the peripheral conductive structures.According to another embodiment, a dielectric-filled gap is disposed between the antenna resonating element arm and the leadframe, wherein the dielectric-filled gap separates the antenna resonating element arm from a first portion of the leadframe by a first distance and separates the antenna resonating element arm from a second portion of the leadframe by a second distance that is less than the first distance.According to another embodiment, the antenna resonating element arm and the second portion of the leadframe form a distributed impedance matching capacitance for the antenna.According to one embodiment, there is provided an electronic device including a housing having peripheral conductive structures, a display in the housing, an antenna resonating element arm for an antenna, the antenna resonating element arm formed from the peripheral conductive structures, and a conductive layer supporting the display and having an extension, the extension of the conductive layer configured to form part of a distributed capacitor for the antenna.According to another embodiment, the extension is separated from the antenna resonating element arm by a first distance, and the extension is disposed between first and second portions of the conductive layer separated from the antenna resonating element arm by at least a second distance greater than the first distance.According to another embodiment, the conductive layer has a rectangular perimeter with top and bottom edges coupled together by left and right edges and a central opening surrounded by the top, bottom, left and right edges.According to another embodiment, the conductive layer forms a portion of an antenna ground for the antenna.According to one embodiment, there is provided an electronic device including a housing having peripheral conductive structures and a planar conductive layer extending between first and second segments of the peripheral conductive structures, a display in the housing, a conductive display frame, a first dielectric-filled gap in the peripheral conductive structures separating the first segment from a third segment of the peripheral conductive structures, a second dielectric-filled gap in the peripheral conductive structures separating the second segment from the third segment, an antenna resonating element for an antenna formed from at least a third segment of the peripheral conductive structures, and an antenna ground formed from at least the planar conductive layer, the first and second segments of the peripheral conductive structures, and the conductive display frame.According to another embodiment, a distributed impedance matching capacitance for the antenna is formed by the conductive display frame and the antenna resonating element.According to another embodiment, the antenna ground includes a first vertical slot extending beyond an edge of the first dielectric filled gap, and wherein the first vertical slot has edges defined by the conductive display frame and the first segment of the peripheral conductive structures.According to another embodiment, the antenna ground includes a second vertical slot extending beyond an edge of the second dielectric filled gap, and wherein the second vertical slot includes edges defined by the conductive display frame and the second segment of the peripheral conductive structures.

Claims

An electronic device (10) comprising: a housing (12) having peripheral conductive structures (16); a display (14) within the housing (12); a conductive frame (308) for the display (14); an antenna resonating element arm (108) for an antenna (40), the antenna resonating element arm (108) formed from a segment of the peripheral conductive structures (16); and an antenna ground (103) for the antenna (40) comprising the conductive frame (308) for the display (14), characterized in that the conductive frame (308) has a first portion separated from the antenna resonating element arm (108) by a first distance and a second portion separated from the antenna resonating element arm (108) by a second distance less than the first distance, and the second portion is configured to form a distributed capacitance with the antenna resonating element arm (108).The electronic device (10) of claim 1, further comprising: an antenna feed (112) for the antenna (40), the antenna feed (112) coupled between the second portion of the conductive frame and the antenna resonating element arm (108).The electronic device (10) of claim 1, further comprising: a conductive display plate (306) coupled to the conductive frame (308), wherein the antenna ground (103) includes the conductive display plate (306).The electronic device (10) of claim 1, wherein the conductive frame (308) has a rectangular perimeter with top and bottom edges coupled together by left and right edges and a central opening (101) surrounded by the top, bottom, left and right edges.The electronic device (10) of claim 1, wherein the segment of the peripheral conductive structures (16) is a first segment, the electronic device (10) further comprising: a first dielectrically-filled gap (18-1) in the peripheral conductive structures (16) separating the first segment from a second segment of the peripheral conductive structures (16); and a second dielectrically-filled gap (18-2) in the peripheral conductive structures (16) separating the first segment from a third segment of the peripheral conductive structures (16).The electronic device (10) of claim 5, wherein the antenna ground (103) comprises the second and third segments of the peripheral conductive structures (16) and a planar conductive layer (320) extending between the second and third segments of the peripheral conductive structures (16).The electronic device (10) of claim 6, further comprising: a conductive structure electrically coupling the planar conductive layer (320) to the conductive frame (308).The electronic device (10) of claim 5, wherein the antenna ground (103) includes a first vertical slot (162) extending beyond an edge of the first dielectric filled gap (18-1), the first vertical slot (162) has edges defined by the conductive frame (308) and the second segment of the peripheral conductive structures (16), the antenna ground (103) includes a second vertical slot (182) extending beyond an edge of the second dielectric filled gap (18-2), and the second vertical slot (182) has edges defined by the conductive frame (308) and the third segment of the peripheral conductive structures (16).The electronic device (10) of claim 1, wherein a dielectric filled gap (18-1) is disposed between the antenna resonating element arm (108) and the first and second portions of the conductive frame (308).

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