PATENT DOCUMENT

Publication Number: US-8208867-B2
Application Number: US-42117809-A
Country: US
Kind Code: B2

Title: Shared multiband antennas and antenna diversity circuitry for electronic devices

Abstract:
Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may have antenna diversity circuitry that allows an optimum antenna or optimum antennas in an antenna structure to be switched into use during device operations. The antenna structure may be shared between multiple radio-frequency transceivers in a radio-frequency transceiver circuit. The radio-frequency transceiver circuit may be coupled to the antenna structure using switching and filtering circuitry. The filtering circuitry may include one or more diplexers that divide radio-frequency signals into divided signal paths based on frequency. The filtering circuitry may also include low pass, high pass, and bandpass filters that are interposed in the divided signal paths. Switching circuitry in the switching and filtering circuitry may be used to selectively configure the wireless communications circuitry in transmit and receive modes using multiple communications bands.

Claims:
1. A portable electronic device, comprising:
 an antenna structure having a first antenna and a second antenna; 
 an antenna diversity switch that selectively switches the first and second antennas into use in response to antenna diversity control signals; 
 radio-frequency transceiver circuitry that transmits and receives radio-frequency signals through the antenna diversity switch, wherein the radio-frequency signals include radio-frequency signals in a first communications band and radio-frequency signals in a second communications band; 
 a diplexer coupled between the antenna structure and the radio-frequency transceiver circuitry, wherein the diplexer has terminals respectively connected to:
 a first path that conveys the radio-frequency signals in the first communications band; 
 a second path that conveys the radio-frequency signals in the second communications band; and 
 an antenna path coupled to the antenna diversity switch; 
 
 an output amplifier in the second path that is interposed between the radio-frequency transceiver circuitry and the diplexer; and 
 a two-position switch interposed in the second path and a three-position switch interposed in the first path. 
 
     
     
       2. The portable electronic device defined in  claim 1  wherein the first and second antennas each cover 2.4 GHz and 5 GHz communications bands and wherein the antenna diversity control signals direct the antenna diversity switch to switch either the first antenna or the second antenna into use. 
     
     
       3. The portable electronic device defined in  claim 1  further comprising a cellular telephone transceiver and cellular telephone antenna. 
     
     
       4. The portable electronic device defined in  claim 1  wherein the diplexer comprises a low-pass filter and a high-pass filter interposed between the antenna structure and the radio-frequency transceiver circuitry, the portable electronic device further comprising a bandpass filter interposed between the diplexer and the radio-frequency transceiver circuitry. 
     
     
       5. The portable electronic device defined in  claim 1  wherein the diplexer comprises a bandpass filter and a high-pass filter interposed between the antenna structure and the radio-frequency transceiver circuitry. 
     
     
       6. Wireless communications circuitry comprising:
 a 5 GHz radio-frequency transceiver that operates in a 5 GHz communications band and a 2.4 GHz radio-frequency transceiver that operates in a 2.4 GHz band; 
 an antenna structure with first and second antennas; 
 a first bandpass filter that is interposed between the 5 GHz radio-frequency transceiver and the antenna structure; 
 a second bandpass filter that is interposed between the 2.4 GHz radio-frequency transceiver and the antenna structure; 
 an antenna diversity switch, wherein the antenna diversity switch has terminals respectively coupled to:
 the first antenna; 
 the second antenna; 
 the first bandpass filter; and 
 the second bandpass filter; and 
 
 a two-position switch and a three-position switch. 
 
     
     
       7. The wireless communications circuitry defined in  claim 6  wherein the antenna diversity switch is configurable in:
 a first configuration in which the first antenna is coupled to the first bandpass filter and the second antenna is coupled to the second bandpass filter; and 
 a second configuration in which the first antenna is coupled to the second bandpass filter and the second antenna is coupled to the first bandpass filter. 
 
     
     
       8. The wireless communications circuitry defined in  claim 6  wherein the two-position switch is coupled between the first bandpass filter and the 5 GHz radio-frequency transceiver. 
     
     
       9. The wireless communications circuitry defined in  claim 6  wherein the three-position switch is coupled between the second bandpass filter and the 2.4 GHz radio-frequency transceiver. 
     
     
       10. The wireless communications circuitry defined in  claim 6  further comprising a cellular telephone transceiver and cellular telephone antenna. 
     
     
       11. An electronic device comprising:
 a housing; 
 transceiver circuitry in the housing that handles wireless local area network radio-frequency signals at 5 GHz and radio-frequency signals at 2.4 GHz; 
 an antenna structure in the housing with first and second antennas; 
 a cellular telephone transceiver and cellular telephone antenna in the housing; 
 a diplexer coupled between the antenna structure and the radio-frequency transceiver circuitry; and 
 an antenna diversity switch, wherein the antenna diversity switch has terminals respectively coupled to:
 the first antenna; 
 the second antenna; 
 the diplexer; and 
 a path coupled to the transceiver circuitry that bypasses the diplexer and that does not pass through a diplexer in the electronic device, wherein the antenna diversity switch is at least operable to simultaneously couple the first antenna to a first one of the diplexer and the path that bypasses the diplexer and couple the second antenna to a second one of the diplexer and the path that bypasses the diplexer. 
 
 
     
     
       12. The electronic device defined in  claim 11  wherein the antenna diversity switch is configurable in:
 a first configuration in which the first antenna is coupled to the diplexer and the second antenna is coupled to the path that bypasses the diplexer; and 
 a second configuration in which the second antenna is coupled to the diplexer and the first antenna is coupled to the path that bypasses the diplexer. 
 
     
     
       13. An electronic device comprising:
 a housing; 
 transceiver circuitry in the housing that handles wireless local area network radio-frequency signals at 5 GHz and radio-frequency signals at 2.4 GHz; 
 an antenna structure in the housing with first and second antennas; 
 a cellular telephone transceiver and cellular telephone antenna in the housing; 
 a diplexer coupled between the antenna structure and the radio-frequency transceiver circuitry; 
 an antenna diversity switch, wherein the antenna diversity switch has terminals respectively coupled to:
 the first antenna; 
 the second antenna; 
 the diplexer; and 
 a path coupled to the transceiver circuitry that bypasses the diplexer; and 
 
 a two-position switch with terminals respectively coupled to: 
 the diplexer; 
 a first path that conveys the radio-frequency signals at 5 GHz to the transceiver circuitry from the antenna structure; and 
 a second path that conveys the radio-frequency signals at 5 GHz from the transceiver circuitry to the antenna structure. 
 
     
     
       14. An electronic device comprising:
 a housing; 
 transceiver circuitry in the housing that handles wireless local area network radio-frequency signals at 5 GHz and radio-frequency signals at 2.4 GHz; 
 an antenna structure in the housing with first and second antennas; 
 a cellular telephone transceiver and cellular telephone antenna in the housing; 
 a diplexer coupled between the antenna structure and the radio-frequency transceiver circuitry; 
 an antenna diversity switch, wherein the antenna diversity switch has terminals respectively coupled to:
 the first antenna; 
 the second antenna; 
 the diplexer; and 
 a path coupled to the transceiver circuitry that bypasses the diplexer; and 
 
 first, second, and third two-position switches, wherein the first two-position switch has terminals coupled to:
 the diplexer; 
 a first path that conveys the radio-frequency signals at 2.4 GHz from the transceiver circuitry to the antenna structure; and 
 the second two-position switch, wherein the second two-position switch has terminals coupled to: 
 the first two-position switch; 
 a second path that conveys the radio-frequency signals at 2.4 GHz to the transceiver circuitry from the antenna structure; and 
 the third two-position switch, and wherein the third two-position switch has terminals coupled to: 
 the second two-position switch; 
 the antenna structure; and 
 a third path that conveys the radio-frequency signals at 2.4 GHz from the transceiver circuitry to the antenna structure. 
 
 
     
     
       15. An electronic device comprising:
 a housing; 
 transceiver circuitry in the housing that handles wireless local area network radio-frequency signals at 5 GHz and radio-frequency signals at 2.4 GHz; 
 an antenna structure in the housing with first and second antennas; 
 a cellular telephone transceiver and cellular telephone antenna in the housing; 
 a diplexer coupled between the antenna structure and the radio-frequency transceiver circuitry; 
 an antenna diversity switch, wherein the antenna diversity switch has terminals respectively coupled to:
 the first antenna; 
 the second antenna; 
 the diplexer; and 
 a path coupled to the transceiver circuitry that bypasses the diplexer; and 
 
 first, second, and third two-position switches, wherein the first two-position switch is configurable in: 
 a first configuration in which the diplexer is coupled to a first path that conveys the radio-frequency signals at 2.4 GHz from the transceiver circuitry to the antenna structure; and 
 a second configuration in which the diplexer is coupled to a first terminal in the second two-position switch, wherein the second two-position switch is configurable in: 
 a first configuration in which the first terminal is coupled to a second path that conveys the radio-frequency signals at 2.4 GHz to the transceiver circuitry from the antenna structure; and 
 a second configuration in which the second path is coupled to a second terminal in the second two-position which, and wherein the third two-position switch is configurable in: 
 a first configuration in which the antenna structure is coupled to the path that bypasses the diplexer; and 
 a second configuration in which the antenna structure is coupled to the second terminal. 
 
     
     
       16. The electronic device defined in  claim 11  further comprising a bandpass filter in the path that bypasses the diplexer.

Description:
BACKGROUND 
     This relates generally to wireless communications circuitry, and more particularly, to electronic devices that support wireless communications in multiple communications bands. 
     Electronic devices such as handheld electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. 
     Devices such as these are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry such as cellular telephone circuitry to communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Long-range wireless communications circuitry may also handle the 2100 MHz band. Electronic devices may use short-range wireless communications links to handle communications with nearby equipment. For example, electronic devices may communicate using the WiFi® (IEEE 802.11) bands at 2.4 GHz and 5 GHz and the Bluetooth° band at 2.4 GHz. 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to reduce the number of components that are used. For example, in some wireless designs a single antenna is shared by two transceivers. Because there is only a single antenna with this type of approach, device size is minimized. 
     It can be difficult to share an antenna in a wireless device, however, because transceivers compete with each other for use of the antenna. This may lead to conflicts when both transceivers are being used. 
     It would therefore be desirable to be able to provide improved wireless communications circuitry for wireless electronic devices. 
     SUMMARY 
     Electronic devices such as handheld electronic devices and other portable electronic devices may be provided with wireless communications circuitry. The wireless communications circuitry may include transceiver circuitry such as transceivers operating at 2.4 GHz and 5 GHz. The wireless communications circuitry may also include cellular telephone transceivers and other radio-frequency transceivers. 
     An electronic device may be provided with an antenna structure for handling transmitted and received radio-frequency signals. The antenna structure may have multiple antennas. Each of the antennas in the antenna structure may cover multiple communications bands such as the 2.4 GHz and 5 GHz bands. An antenna diversity switch may be controlled in real time to switch one of the antennas in the antenna structure into use. For example, if a first of the antennas is receiving signals more effectively than a second of the antennas, the antenna diversity switch may be used to switch the first antenna in to use, thereby optimizing wireless performance. With another suitable arrangement, an antenna diversity switch may be controlled in real time to switch a first antenna into use in transmitting wireless signals and a second antenna into use in receiving wireless signals. In this type of arrangement, if the first antenna is transmitting signals more effectively than the second antenna (and any other antennas), the antenna diversity switch may be used to switch the first antenna into use as a transmitting antenna and to switch the second antenna into use as a receiving antenna (as examples), thereby optimizing wireless performance (e.g., optimizing antenna transmission efficiency). Alternatively, if the first antenna is receiving signals more effectively than the second antenna (and any other antennas), the antenna diversity switch may be used to switch the first antenna into use as a receiving antenna and to switch the second antenna into use as a transmitting antenna (as examples), thereby optimizing wireless performance (e.g., optimizing antenna reception efficiency). 
     The antenna structure may be shared between 2.4 GHz and 5 GHz transceivers using filter and switching circuitry. The filter and switching circuitry may include one or more diplexers that are coupled between multiple communications paths and the antenna diversity switch. Each diplexer may be coupled between first and second communications paths and the antenna diversity switch. The first path may be used to convey radio-frequency signals in a first communications band such as the 2.4 GHz communications band. The second path may be used to convey radio-frequency signals in a second communications band such as the 5 GHz communications band. The diplexers may be formed from a low pass filter (or a corresponding bandpass filter) and a high pass filter (or a corresponding bandpass filter. For example, a diplexer may have a 5 GHz bandpass filter that is coupled to the second path and a 2.4 GHz low pass filter that is coupled to the first path. In another example, a diplexer may have a 5 GHz high pass filter and a 2.4 GHz band pass filter. In general, any suitable combinations of filters may be included in the diplexers. 
     Low pass, high pass, and/or bandpass filtering circuitry in the filter and switching circuitry may be interposed in the first and second paths. For example, a 2.4 GHz bandpass filter may be interposed in the first path between the transceiver circuitry and the diplexer, whereas a 5 GHz bandpass filter may be interposed in the second path between the transceiver circuitry and the diplexer. With another suitable arrangement, filter and switching circuitry may include a pair of filters (e.g., a 5 GHz bandpass filter and a 2.4 GHz bandpass filter) each of which is coupled between the antenna diversity switch and one of the two communications paths. 
     Switching circuitry such as two-position switches and three-position switches may be used to configure the device for various 2.4 GHz and 5 GHz transmission and reception modes. For example, the switching circuitry may be configured to support simultaneous signal transmission at 5 GHz and signal reception at 2.4 GHz or may be configured to support simultaneous signal reception at 5 GHz and signal transmission at 2.4 GHz (as examples). 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 3  is a schematic diagram of wireless communications circuitry for a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 4  is a detailed schematic diagram of wireless communications circuitry that may include two diplexers and a switch for a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 5  is a detailed schematic diagram of wireless communications circuitry that may include two diplexers and two switches for a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 6  is a detailed schematic diagram of wireless communications circuitry that may include a diplexer and three switches for a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 7  is a detailed schematic diagram of wireless communications circuitry that may include a diplexer and three switches for a wireless electronic device and that may include a transmission line dedicated to signals in a given communications band in accordance with an embodiment of the present invention. 
         FIG. 8  is a detailed schematic diagram of wireless communications circuitry that may include a diplexer and five switches for a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 9  is a detailed schematic diagram of wireless communications circuitry that may include a diplexer with a high-pass filter and a bandpass filter and three switches for a wireless electronic device in accordance with an embodiment of the present invention. 
         FIG. 10  is a detailed schematic diagram of wireless communications circuitry that may include two bandpass filters and three switches for a wireless electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in multiple wireless communications bands. Antenna resources in an electronic device may be shared between multiple transceivers. For example, a transceiver circuit that is operating in first and second communications bands may share an antenna. More than one antenna may be shared in this way. For example, multiple antennas may be used to implement an antenna diversity scheme in which switching circuitry continuously switches an optimum antenna into use depending on factors such as antenna signal strength. 
     An electronic device may therefore be provided with an antenna structure that has one or more diversity antennas and multiple transceivers that share the antenna structure. In the same electronic device, additional transceivers may be provided that use separate antennas. For example, an electronic device may contain antenna sharing circuitry that allows IEEE 802.11 (WiFi®) and Bluetooth® transceivers to share antenna resources. The same device may also be provided with additional transceivers such as a cellular telephone transceiver. If desired, the same device may include a global positioning system (GPS) receiver. The antenna sharing circuitry may contain filters that help block cross-talk from the cellular telephone transceiver and the global position system receiver and from leaked versions of transmitted signals while supporting antenna sharing operations between the WiFi and Bluetooth transceivers (as an example). 
     Any suitable electronic devices may be provided with wireless circuitry that supports antenna resource sharing. As an example, antenna sharing may be supported in electronic devices such as desktop computers, game consoles, routers, laptop computers, etc. With one suitable configuration, antenna sharing circuitry is provided in relatively compact electronic devices in which interior space is relatively valuable such as portable electronic devices. 
     An illustrative portable electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Portable electronic devices such as illustrative portable electronic device  10  may be laptop computers or small portable computers such as ultraportable computers, netbook computers, and tablet computers. Portable electronic devices may also be somewhat smaller devices. Examples of smaller portable electronic devices include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. With one suitable arrangement, the portable electronic devices are handheld electronic devices such as cellular telephones. 
     Space is at a premium in portable electronic devices, so antenna-sharing arrangements for portable electronic devices can be particularly advantageous. The use of portable devices such as handheld devices is therefore sometimes described herein as an example, although any suitable electronic device may be provided with antenna resource sharing circuitry if desired. 
     Handheld devices may be, for example, cellular telephones, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controllers, global positioning system (GPS) devices, and handheld gaming devices. Handheld devices and other portable devices may be hybrid devices that combine the functionality of multiple conventional devices. Examples of hybrid devices include a cellular telephone that includes media player functionality, a gaming device that includes a wireless communications capability, a cellular telephone that includes game and email functions, and a handheld device that receives email, supports mobile telephone calls, and supports web browsing. These are merely illustrative examples. Device  10  may be any suitable portable or handheld electronic device. 
     Device  10  includes housing  12  and includes at least one antenna for handling wireless communications. Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, wood, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, case  12  may be a dielectric or other low-conductivity material, so that the operation of conductive antenna elements that are located in proximity to case  12  is not disrupted. In other situations, case  12  may be formed from metal elements. 
     Any suitable type of antenna may be used to support wireless communications in device  10 . Examples of suitable antenna types include antennas with resonating elements that are formed from a patch antenna structure, a planar inverted-F antenna structure, a helical antenna structure, etc. To minimize device volume, at least one of the antennas in device  10  may be shared between two transceiver circuits. 
     Handheld electronic device  10  may have input-output circuitry  14 . Circuitry  14  may include devices such as a display screen, buttons, alphanumeric keys, touch pads, pointing sticks, and other user input control devices for receiving user input, and input-output components such as input-output ports. Device  10  may use any suitable type of display such as a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a plasma display, or multiple displays that use one or more different display technologies. Display screens can be mounted on the front face of handheld electronic device  10  as shown by circuitry  14  in  FIG. 1 . If desired, displays can be mounted on the rear face of handheld electronic device  10 , on a side of device  10 , on a flip-up portion of device  10  that is attached to a main body portion of device  10  by a hinge (for example), or using any other suitable mounting arrangement. 
     Device  10  may interact with external equipment wirelessly. If desired, antenna diversity arrangements may be implemented in device  10  in which multiple redundant antennas are used to transmit and receive signals. The antennas in an antenna diversity arrangement may be located in different portions of device  10 . For example, a first antenna may be located in region  15 , whereas a second antenna may be located in region  17 . During operation of the wireless antennas, antenna diversity circuitry in device  10  may make signal strength readings or other appropriate readings in real time to continuously determine which antenna is performing best. The antenna diversity circuitry can then ensure that the optimum antenna is switched into use, maximizing wireless performance in device  10 . 
     With one suitable arrangement, the antenna diversity circuitry can be used to ensure that wireless communications are not disabled when one or more antennas in device  10  are malfunctioning (i.e., when an antenna is broken from inadvertently dropping device  10  on a hard surface). For example, when at least one antenna in device  10  remains functional, the antenna diversity circuitry can ensure that the functional antenna is switched into use, maintaining wireless functionality in device  10 . 
     A schematic diagram of an embodiment of an illustrative handheld electronic device is shown in  FIG. 2 . Handheld device  10  may be a portable computer such as a portable tablet computer, a mobile telephone, a mobile telephone with media player capabilities, a handheld computer, a remote control, a game player, a global positioning system (GPS) device, a combination of such devices, or any other suitable portable electronic device. 
     As shown in  FIG. 2 , handheld device  10  may include storage and processing circuitry  16 . Storage and processing circuitry  16  may include one or more different types of storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  16  may be used to control the operation of device  10 . Processing circuitry  16  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, storage and processing circuitry  16  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VoIP) telephone call applications, email applications, media playback applications, operating system functions, etc. Storage and processing circuitry  16  may be used in implementing suitable communications protocols and may be used in implementing antenna diversity schemes. Communications protocols that may be implemented using storage and processing circuitry  16  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth° protocol, etc. 
     Input-output circuitry  14  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  18  such as touch screens and other user input interface are examples of input-output circuitry  14 . Input-output devices  18  may also include user input-output devices such as buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, etc. A user can control the operation of device  10  by supplying commands through such user input devices. Display and audio devices may be included in devices  18  such as liquid-crystal display (LCD) screens, light-emitting diodes (LEDs), and other components that present visual information and status data. Display and audio components in input-output devices  18  may also include audio equipment such as speakers and other devices for creating sound. If desired, input-output devices  18  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     Wireless communications circuitry  20  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, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). Wireless communications circuitry  20  may include radio-frequency transceiver circuits for handling multiple radio-frequency communications bands. For example, circuitry  20  may include transceiver circuitry  22  that handles 2.4 GHz and 5 GHz bands for WiFi (IEEE 802.11) communications and the 2.4 GHz Bluetooth communications band. Circuitry  20  may also include cellular telephone transceiver circuitry  24  for handling wireless communications in cellular telephone bands such as the GSM bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, and the 2100 MHz data band (as examples). Wireless communications circuitry  20  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  20  may include global positioning system (GPS) receiver equipment, wireless circuitry for receiving radio and television signals, paging circuits, etc. In WiFi and Bluetooth links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. 
     Wireless communications circuitry  20  may include antennas  26 . Antennas  26  may be formed using any suitable antenna types. Examples of suitable antenna types for antennas  26  include antennas with resonating elements that are formed from patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link. 
     Examples of local wireless links include WiFi and Bluetooth links and wireless universal serial bus (USB) links. Because WiFi links are typically used to establish data links with local area networks, links such as WiFi links are sometimes referred to as wireless local area network (WLAN) links. 
     Local wireless links may operate in any suitable frequency band. For example, WLAN links may operate at 2.4 GHz and 5 GHz (as examples), whereas Bluetooth links may operate at 2.4 GHz. The frequencies of the WLAN channels that are used in supporting these local links in device  10  may depend on the country in which device  10  is being deployed (e.g., to comply with local regulations), the available hardware of the WLAN or other equipment with which device  10  is connecting, and other factors. 
     With one suitable arrangement, which is sometimes described herein as an example, device  10  includes long-range wireless circuitry such as cellular telephone transceiver circuitry  24  and short-range circuitry such as transceiver circuits  22 . Circuitry  24  may operate with a single long-range link antenna (e.g., a multiband cellular telephone antenna). Circuitry  22  may support communications in both the 2.4 GHz and 5 GHz WiFi bands and in the 2.4 GHz Bluetooth band using a shared antenna or shared antennas. 
     In devices that do not have multiple antennas for implementing an antenna diversity scheme, circuitry  22  may include sharing circuitry that allows multiple transceiver circuits to share a single multiband antenna. For example, sharing circuitry may be used to allow a WiFi transceiver that operates at 2.4 GHz and at 5 GHz to share the same antenna as a Bluetooth transceiver that operates at 2.4 GHz. 
     The same type of sharing scheme may be implemented in devices  10  that have multiple antennas arranged to support an antenna diversity scheme. To support antenna diversity, multiple antennas are provided each of which may cover the same communications bands (e.g., bands at 2.4 GHz and 5 GHz). Antenna diversity switching circuitry may be used to switch an optimum one of the antennas into use at a given time. In a typical scenario, signal strength monitoring circuitry or other control circuitry may make measurements in real time to determine which of the antennas is providing the best performance (e.g., maximum signal strength) in the current environment for device  10 . With one suitable arrangement, signal strength monitoring circuitry or other control circuitry may make receiver power measurements and/or signal strength measurements for each of the appropriate antennas in device  10  during the preamble window of each incoming data packet (as an example). The preamble window may be transmitted and received over approximately 10 microseconds and an average data packet may be transmitted and received over approximately 10 milliseconds (as an example). With this type of arrangement, device  10  may determine which of the antennas is providing the best performance using measurements made during the approximately 10 microsecond time frame of the preamble window. Based on these measurements, the control circuitry may direct the antenna diversity switching circuitry to switch the optimum antenna into use. As a user moves device  10  and covers various parts of device  10  with the user&#39;s hands, antenna performance may be degraded. With the antenna diversity scheme, the unblocked antenna (if available) can be switched into use. 
     Device  10  may include sharing circuitry that allows multiple transceivers to share a single antenna or that allows multiple transceivers to share a single antenna structure containing multiple subantennas in a diversity arrangement. For clarity, the antenna sharing operations of device  10  are sometimes described in connection with arrangements in which the shared antenna structures include multiple antennas arranged in an antenna diversity configuration. This is, however, merely illustrative. Antenna sharing circuitry in device  10  may be used to allow any suitable transceivers to share any suitable antenna structures if desired. 
     With an illustrative antenna sharing arrangement, the shared antenna structures may be designed to operate at frequencies of both 2.4 GHz and 5 GHz, so the shared antenna structures are suitable for use with both the 2.4 GHz radio-frequency signals that are used in connection with both the WiFi and Bluetooth communications protocols and the 5 GHz radio-frequency signals that are used in connection with WiFi communications protocols. 
       FIG. 3  shows how wireless communications circuitry  20  may have switching and filtering circuitry  28 . Switching and filtering circuitry  28  may include antenna sharing circuitry that selectively couples multiple transceivers in radio-frequency transceiver circuitry  22  to antennas  26 . Radio-frequency transceiver circuitry  22  may include a WiFi transceiver (radio) for handling WiFi signals at 2.4 GHz and 5 GHz and a Bluetooth transceiver (radio) for handling Bluetooth signals at 2.4 GHz. These radios may be provided using a single integrated circuit or using two or more integrated circuits. Antennas  26  may include multiple antennas arranged in an antenna diversity configuration. Each of the multiple antennas may be configured to handle signals at 2.4 GHz and 5 GHz. Circuitry  28  may include switches such as transistor-based switches, amplifiers such as power amplifiers and low-noise amplifiers, discrete components such as inductors, capacitors, and resistors, etc. 
       FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10  illustrate various arrangements for providing wireless communications circuitry  20 . As shown in  FIG. 4  (as an example), circuitry  20  may include radio-frequency transceiver circuitry  22 . Radio-frequency transceiver circuitry  22  may include WiFi and Bluetooth transceivers (as an example). The WiFi transceiver may operate in the 2.4 GHz WiFi communications band and the 5 GHz WiFi communications band. The Bluetooth transceiver may operate in the 2.4 GHz band. These transceiver circuits may be provided using one, two, three, or more than three transceiver circuits. In the example of  FIG. 4 , circuitry  22  is shown as containing a WiFi transceiver for 5 GHz operation (transceiver  106 ), a WiFi transceiver for 2.4 GHz operation (transceiver  108 ), and a Bluetooth transceiver for 2.4 GHz operation (transceiver  110 ). These circuits may be implemented using different portions of one or more integrated circuits and may be organized in a variety of configurations. As an example, circuitry  22  may have a WiFi block or chip such as transceiver  107  (illustrated by the dashed lines around transceivers  106  and  108 ) that serves to implement both 5 GHz and 2.4 GHz WiFi transceiver functions in a single transceiver integrated circuit. The examples of circuitry  20  and circuitry  22  shown in  FIG. 4  may also be applied to the circuits of  FIGS. 5 ,  6 ,  7 ,  8 ,  9 , and  10 , if desired. 
     With one suitable arrangement, paths  30  and  32  may be coupled to 5 GHz WiFi transceiver  106 , paths  40  and  42  may be coupled to 2.4 GHz WiFi transceiver  108 , and paths  42  and  44  may be coupled to Bluetooth transceiver  110 . Transceivers  108  and  110  may be coupled to path  42  through a splitter such as splitter  101  or other suitable circuitry. If transceivers  106  and  108  are combined into a single transceiver such as chip  107 , paths  30 ,  32 ,  40 , and  42  may be coupled to chip  107 . There are merely illustrative examples. 
     Circuitry  20  may also include other radio-frequency transceiver circuitry such as illustrative cellular telephone transceiver circuitry  98 . Radio-frequency receivers and other circuits may be used to receive GPS signals, radio and video signals, other communications signals, etc. Circuitry  20  is depicted as containing radio-frequency transceiver circuitry  22  and radio-frequency transceiver circuitry  98 . This is, however, merely illustrative. Wireless communications circuitry  20  may include any suitable wireless circuitry if desired. 
     Circuitry  22  and circuitry  98  may include resources that serve as control circuits and may therefore be considered to serve as some of the storage and processing circuitry that is depicted as storage and processing circuitry  16  of  FIG. 2 . Wireless communications circuitry  20  may also be interconnected with other storage and processing circuits. 
     For example, conductive paths  96  may be used to interconnect radio-frequency transceiver circuitry  22  and radio-frequency transceiver circuitry  98  to control circuitry in device  10  (e.g., storage and processing circuitry  16  of  FIG. 2 ). Paths  96  may be used for power supply signals (e.g., one or more positive power supply voltages and one or more ground voltages), input and output data signals (e.g., general purpose input-output or GPIO signals), serial and parallel port signals (e.g., universal asynchronous receiver transmitter or UART signals), testing signals (e.g., testing signals compliant with Joint Test Action Group or JTAG protocols), pulse-code-modulation (PCM) signals (e.g., audio signals), WLAN data and Bluetooth data, clock signals, power management signals, other control and data signals, etc. 
     Radio-frequency transceiver circuitry  22  may transmit and receive radio-frequency signals using antennas  26  and, if desired, antenna  27 . As one example, antenna  27  may be a dedicated Bluetooth antenna (e.g., a 2.4 GHz antenna used by device  10  to transmit Bluetooth signals). Circuitry  20  may include multiple antennas  26  that are arranged to implement an antenna diversity scheme. As an example, antennas  26  include a first antenna such as antenna  26 A and a second antenna such as antenna  26 B. These antennas are connected to switching circuitry  72 . Switching circuitry  72  may be controlled in real time to ensure that antenna performance is maximized. 
     Switching circuitry  72  may be implemented using a double pole, double throw (DPDT) switch. With this type of arrangement, switching circuitry  72  may be used to selectively route transmission signals to the antenna with the best (current) performance while routing signals from the other antenna to receiver circuitry. When, for example, antenna  26 A is performing better than antenna  26 B, switching circuitry  72  may be used to switch antenna  26 A into use for wireless transmissions by coupling antenna  26 A to lines carrying transmission signals (e.g., coupling antenna  26 A to path  62 ) and to switch antenna  26 B into use by coupling antenna  26 B to wireless receivers in circuitry  22  through receiver lines (e.g., coupling antenna  26 B to path  82 ). When, for example, antenna  26 B is performing better than antenna  26 A, switching circuitry  72  may be used to switch antenna  26 B into use for wireless transmissions by coupling antenna  26 B to lines carrying transmission signals (e.g., coupling antenna  26 B to path  62 ) and to switch antenna  26 A into use by coupling antenna  26 A to wireless receivers in circuitry  22  through receiver lines (e.g., coupling antenna  26 A to path  82 ). Antennas  26 A and  26 B work together to handle signals for radio-frequency transceiver circuitry  22  and are sometimes collectively referred to as an antenna or antenna structure. 
     During operation, the control circuitry of transceiver circuitry  22  may produce control signals DCONTROL on one or more lines in control path  38 . The control signals DCONTROL may be routed to the control input of switch  72  and may be used to control whether terminals  48  and  50  are connected to terminals  52  and  56  (respectively) or whether terminals  48  and  50  are connected to terminals  54  and  58  (respectively). Antenna selection decisions may be based on received signal quality measurements (e.g., on a packet-by-packet basis) or any other suitable input. Based on this input, circuitry  22  may generate control signals DCONTROL that place switch  72  in a state that switches an optimum antenna into use for transmission operations (i.e., antenna  26 A or  26 B in the  FIG. 4  example). If desired, circuitry  22  may switch the optimum antenna into use for receiving operations in situations in which the receiving antenna  26  has insufficient signal quality (e.g., to ensure that receiving operations can continue). 
     With another suitable arrangement, antenna switching circuitry in circuitry  20  may be implemented using a single pole, double throw (SPDT) switch. This arrangement is illustrated by the dashed lines and interconnections to switching circuitry  73  in  FIG. 4  (and in  FIGS. 6 and 9 ). When antenna  26 A is performing better than antenna  26 B, switching circuitry  73  may be used to switch antenna  26 A into use by radio-frequency transceiver circuitry  22 , as an example. When antenna  26 B is performing better than antenna  26 A, antenna  26 B can be used by radio-frequency transceiver circuitry  22 . 
     With this type of arrangement, the control circuitry of transceiver circuitry  22  may produce control signals DCONTROL on one or more lines in control path  39  during operation. The control signals DCONTROL may be routed to the control input of switch  73  and may be used to control whether terminal  49  is connected to terminal  51  or to terminal  53  (e.g., antenna  26 A or antenna  26 B, respectively). Antenna selection decisions may be based on received signal quality measurements (e.g., on a packet-by-packet basis) or any other suitable input. Based on this input, circuitry  22  may generate control signals DCONTROL that place switch  73  in a state that switches an optimum antenna into use (i.e., antenna  26 A or  26 B). 
     Radio-frequency transceiver circuitry  98  may transmit and receive radio-frequency signals using one or more antennas such as antenna  100 . Particularly in compact electronic devices such as handheld electronic devices and other portable electronic devices, there is a relatively short distance between antenna  100 , antennas  26 , and antenna  27 . This can result in potential cross-talk signals such as when transmitted radio-frequency signals from antenna  100  are coupled to antennas  26  via free space path  102 , when signals transmitted from antennas  26  are coupled to antenna  100  via path  102 , when signals transmitted from antennas  100  are coupled to antenna  27  via free space path  103 , when signals transmitted from antennas  26  are coupled to antenna  27  via path  105 , and when signals transmitted from antenna  27  are coupled to antennas vias path  105  (as examples). Circuitry  20  may include switching and filter circuitry that effectively suppresses these sources of undesirable crosstalk and thereby ensures proper operation of radio-frequency transceiver circuitry  22  even when radio-frequency transceiver circuitry  98  is operated simultaneously. 
     Wireless communications circuitry  20  may include antenna sharing circuitry that allows antennas  26  to be shared by the WiFi and Bluetooth transceivers of circuitry  22 . Circuitry  20  may include one or more frequency-dependent multiplexing elements such as diplexers  63  and  65  ( FIGS. 4 and 5 ) and diplexer  64  ( FIGS. 6 ,  7 ,  8 , and  9 ). Circuitry  20  may also include switching circuitry such as switch  112  ( FIG. 5 ); switches  120  and  130  ( FIGS. 6 and 9 ); switches  138  and  146  ( FIG. 7 ); switches  154 ,  162 ,  170 , and  178  ( FIG. 8 ); and switches  204  and  212  ( FIG. 10 ). The states of these switches may be adjusted during operation of circuitry  20  to route transmitted and received radio-frequency signals to appropriate locations. 
     In the example of  FIG. 4 , radio-frequency transceiver circuitry  22  may transmit signals in the 5 GHz WiFi band using output path  30  and may transmit signals in the 2.4 GHz WiFi band using output path  40 . Paths  30  and  40  may be connected to diplexer  65 . If desired, path  30  may include amplifier  222  to boost the transmitted signals on path  30 . 
     Diplexer  65  serves as a frequency-dependent multiplexing element. Diplexer  65  may receive signals at 2.4 GHz and 5 GHz over paths  30  and  40 . The 2.4 GHz and the 5 GHz signals may be routed to path  62  (e.g., to antennas  26 ) by diplexer  65 . 
     Diplexers such as diplexers  63 ,  64 ,  65 , and  70  may be implemented using any suitable radio-frequency components. With one suitable arrangement, diplexers  63 ,  64 ,  65 , and  70  may be implemented using filters such as filters  66 ,  68 , and  69 . Diplexers  63 ,  64 , and  65  may use filters  66  and  68  and diplexer  70  may use filters  68  and  69 , as examples. Filter  66  may be a 2.4 GHz low-pass filter that passes radio-frequency signals at frequencies below 2.5 GHz (as an example). Filter  68  may be a 5 GHz high-pass filter that passes radio-frequency signals at frequencies above 4.8 GHz or above 4.9 GHz (as an example). Filter  69  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). More extensive filtering may be performed using filters such as filters  74 ,  76 ,  77 ,  86 , and  88 . Filter  74  may be a 2.4 GHz low-pass filter that passes radio-frequency signals at frequencies below 2.5 GHz or may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as examples). Filter  76  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). Filter  77  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). Filter  86  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). Filter  88  may be a 5 GHz bandpass filter that passes radio-frequency signals in the range of 4.9 GHz to 6 GHz (as an example). 
     In the example of  FIG. 4 , Bluetooth signals at 2.4 GHz may be transmitted from circuitry  22  using antenna  27 . As examples, Bluetooth transceiver  110  or other radio-frequency transceiver circuitry  22  may generate Bluetooth transmission signals that are conveyed to Bluetooth antenna  27  over transmission path  44 . 
     In the example of  FIG. 4 , path  82  and diplexer  63  may be used to route incoming radio-frequency signals from antennas  26  to input paths  32  and  42  of radio-frequency transceiver circuitry  22 . Input path  42  may carry signals in the 2.4 GHz WiFi band and signals in the 2.4 GHz Bluetooth band. Input path  32  may carry signals in the 5 GHz WiFi band. 
     If desired, circuitry  20  may include one or more (optional) amplifiers such as low noise amplifiers  92 . Low-noise amplifiers  92  may be controlled by circuitry  22  using one or more enable signals such as the signal “ENABLE” on line  34 . When the signal ENABLE on line  34  is asserted by radio-frequency transceiver circuitry  22 , low-noise amplifiers  92  will be turned on. When not required to amplify incoming signals, low-noise amplifiers  92  can be disabled to conserve power by deasserting the ENABLE signal. As shown in the dashed outlines of lines  34  and amplifiers  92  in  FIG. 4 , circuitry  20  may include an amplifier in path  82 , an amplifier in path  42 , and/or an amplifier in path  32  (as examples). 
     With the arrangement shown in  FIG. 4 , device  10  may be able to maximize the airtime of Bluetooth transmission (because Bluetooth transmission path  44  may be coupled to a dedicated Bluetooth antenna  27 ). In addition, there may be relatively little crosstalk between the 2.4 GHz transmission path  40  (e.g., transmission line  40 ) and the 5 GHz receiving line  32  (because crosstalk signals may have to pass through diplexers  63  and  65  to cross between path  40  and line  32 ). Also, it may be possible to simultaneously transmit 2.4 GHz and 5 GHz signals for wireless communications (because paths  30  and  40  are simultaneously connected to antennas). It may be desirable to include relatively robust antennas  26  in circuitry of the type shown in  FIG. 4  to reduce the risk of one of the antennas  26  breaking. In addition, it may be desirable to provide antennas  26  that are relatively isolated from each other to reduce potential crosstalk signals between the two antennas  26  during the simultaneous operation of the two antennas  26 . If desired, diplexers  63  and  65  may include relatively high quality filters to reduce potential cross talk signals from cellular telephone antenna  100  and from the two antennas  26 . With one suitable arrangement, filters may be included in path  30  (e.g., the 5 GHz transmission line) to provide harmonic filtering for path  30 . 
       FIGS. 5 ,  6 ,  7 ,  8 ,  9 , and  10  illustrate alternative arrangements for providing wireless communications circuitry  20 . If desired, any of the alternative arrangements described in connection with  FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10  may be applied in any of the other examples in  FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10 . 
     The arrangement of  FIG. 5  may have many of the same benefits as  FIG. 4  while simultaneously reducing the number of antennas in device  10  (e.g., by eliminating the dedicated Bluetooth antenna  27  of  FIG. 4 ). Because device  10  of  FIG. 5  need not include a dedicated Bluetooth antenna, it may be desirable to implement a time-sharing technique or other suitable technique to maximize the coexistence of Bluetooth transmissions and 2.4 GHz WiFi transmissions (e.g., to maximize the airtimes of Bluetooth and 2.4 GHz WiFi transmissions). 
     In the example of  FIG. 5 , the arrangement of  FIG. 4  may be modified by utilizing a switch such as switch  72  to route Bluetooth transmission signals to path  62  and antenna  26 . If desired, this type of arrangement may be used in an electronic device that does not include a dedicated Bluetooth antenna such as antenna  27  (as an example). As shown in  FIG. 5 , Bluetooth signals at 2.4 GHz may be transmitted from circuitry  22  using antennas  26  (e.g., using one of the two antennas  26 A or  26 B). As examples, Bluetooth transceiver  110  or radio-frequency transceiver circuitry  22  may generate Bluetooth transmission signals that are conveyed to terminal  116  of switch  112 . Radio-frequency transceiver circuitry  22  may generate transmission signals in the 2.4 GHz WiFi band using output path  40  that are conveyed to terminal  114  of switch  112 . 
     Switch  112  may be used to connect terminal  118  to either terminal  114  or terminal  116  depending on the state of one or more control signals. These control signals may be provided to switch  112  from radio-frequency transceiver circuitry  22  over one or more control lines. These control lines and associated control signals are shown as control path  113  and control signal CONTROL in  FIG. 5 . When terminal  114  is connected to terminal  118 , 2.4 GHz WiFi signals can be transmitted from radio-frequency transceiver circuitry  22  using one of antennas  26 . When terminal  116  is connected to terminal  118 , Bluetooth transmission signals can be transmitted from radio-frequency transceiver circuitry  22  using one of antennas  26 . 
     In the  FIG. 6  example, filter  76  may be connected to filter  66  and, in the  FIG. 7  example, filter  74  may be connected to filter  69 . By using both filters  76  and  66  and/or filters  74  and  69  together, filtering for the 2.4 GHz signal path in circuitry  20  can be enhanced, without incurring large insertion losses. If desired, the filtering circuitry of filters  76  and  66  and/or filters  74  and  69  may be implemented using a unitary device, although this will typically result in a somewhat increased insertion loss penalty. In addition to exhibiting low insertion losses, the use of separate filters  76  and  66  and/or  74  and  69  may help to reduce leaked 5 GHz signals in diplexers  64  and  70  (respectively) from propagating to the input of the 2.4 GHz receiver circuitry in circuitry  22  during 5 GHz transmission operations. The bulk (e.g., 90%) of the filtering performed by filters  76  and  66  with the  FIG. 6  arrangement will generally be provided by filter  76 . The bulk (e.g., 90%) of the filtering performed by filters  74  and  69  with the  FIG. 7  arrangement will generally be provided by filter  74 . 
     In the example of  FIG. 6 , circuitry  20  may include a diplexer  64  coupled to switching circuitry  73  and antennas  26 . Diplexer  64  may convey 2.4 GHz radio-frequency signals between switch  120  and switching circuitry  73  and may convey 5 GHz radio-frequency signals between switch  130  and switching circuitry  73  (as examples). With one suitable arrangement, diplexer  64  of  FIG. 6  may include 5 GHz high-pass filter  68  and 2.4 GHz low-pass filter  66 . If desired, circuitry  20  may include filter  76  between switch  120  and diplexer  64 . Filter  76  may be formed from a 2.4 GHz bandpass filter and, as one example, may help to block 5 GHz transmission signals from path  30  leaking into terminal  128  (and path  42 ) and may help to block radio-frequency telephone signals that have been coupled into antennas  26  via path  102  from propagating to terminal  128  (and path  42 ). 
     Switch  120  may be implemented as part of a larger circuit such as circuit  119 . Circuit  119  may be, for example, an integrated circuit that contains an integrated low-noise radio-frequency input amplifier such as amplifier  121 . Components such as these may also be provided using one or more separate devices. The arrangement of  FIG. 6 , in which low-noise amplifier  121  and switch  120  are implemented as parts of a common integrated circuit  119  is merely illustrative. 
     Switch  120  may be a three-position switch (as an example). With a three-position configuration, switch  120  may be used to connect terminal  128  to terminal  122 , terminal  124 , or terminal  126 . Control signals CONTROL may be provided to switch  120  from radio-frequency transceiver  22  to select which of the three positions is used. 
     When it is desired to transmit 2.4 GHz WiFi signals, control signals CONTROL on path  123  may be used to direct switch  120  to connect path  40  to terminal  128 . In this configuration, 2.4 GHz WiFi signals that are transmitted on output path  40  by radio-frequency transceiver circuitry  22  may be routed to diplexer  64 . Signals at 2.4 GHz may be routed from antennas  26  to 2.4 GHz input path  42  by placing switch  120  in position  122  and routing incoming signals to path  42  through low-noise amplifier  121 . Transceiver circuitry  22  (e.g., circuitry  22  and the code running on transceiver circuitry  22 ) may be used to process simultaneously received 2.4 GHz Bluetooth signals and 2.4 GHz WiFi signals on path  42 . Transceiver circuitry  22  may, for example, separately process Bluetooth and WiFi signals, allowing for simultaneous receive operations. When it is desired to transmit 2.4 Bluetooth signals, control signals CONTROL on path  123  may be used to direct switch  120  to connect path  44  to terminal  128 . In this configuration, 2.4 GHz Bluetooth signals that are transmitted on output path  44  by radio-frequency transceiver circuitry  22  may be routed to diplexer  64 . 
     Switch  130  may be used to connect diplexer  64  to either path  30  or path  32  depending on the state of one or more control signals. These control signals may be provided to switch  130  from radio-frequency transceiver circuitry  22  over one or more control lines. These control lines and associated control signals are shown as control path  131  and control signal HCONTROL in  FIG. 6 . When diplexer  64  is connected to path  30  (e.g., terminal  136  is connected to terminal  132 ), 5 GHz WiFi signals can be transmitted from radio-frequency transceiver circuitry  22  using one of antennas  26 . When diplexer  64  is connected to path  32  (e.g., terminal  136  is connected to terminal  134 ), 5 GHz WiFi signals that have been received using antennas  26  can be routed to radio-frequency transceiver circuitry  22 . If desired, path  30  may include amplifier  222  to boost the transmission signals on path  30 . With another suitable arrangement, amplifier  222  may be integrated into radio-frequency transceiver circuitry  22  (e.g., amplifier  222  may be integrated into radio  106 ). 
     With the arrangement shown in  FIG. 6 , the coexistence of 2.4 GHz WiFi and Bluetooth signals and 5 GHz WiFi signals need not be dependent on the ability to implement a large amount of isolation between the two antennas  26  (e.g., there may be relatively poor isolation between each of the two antennas  26  without reducing coexistence between 2.4 GHz and 5 GHz signals). In addition, device  10  may be able to use whichever antenna currently has the strongest signal strengths, thereby maximizing wireless communications performance. The arrangement of  FIG. 6  may also exhibit sufficient filtering to effectively eliminate crosstalk signals from cellular telephone antenna  100  and GPS antennas. If desired, diplexer  64  may include relatively high quality filters to reduce the amount of signals that leak from transmission lines  40  and/or  44  to receiving line  32  and to allow simultaneous transmission operations through transmission lines  40  and/or  44  and receiving operations through receiving line  32 . With one suitable arrangement, filters may be included in path  30  (e.g., the 5 GHz transmission line) to provide harmonic filtering for path  30 . In addition, the arrangement of  FIG. 6  may provide redundancy in the event that one of the two antennas  26  breaks or fails (e.g., wireless communications can continue even if one of the two antennas  26  breaks). 
     In the example of  FIG. 7 , circuitry  20  may include a diplexer  70  and a Bluetooth transmission path  44  coupled to switching circuitry  72  and antennas  26 . Path  44  (and path  62 ) may convey 2.4 GHz radio-frequency signals between circuitry  22  (radio  110 ) and switching circuitry  72 . If desired, circuitry  20  may include filter  77  between output path  44  and switching circuitry  72 . Filter  77  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). With one suitable arrangement, diplexer  70  may convey 2.4 GHz radio-frequency signals between switch  146  and path  82  (e.g., switching circuitry  72 ) and may convey 5 GHz radio-frequency signals between switch  138  and path  82  (as examples). As an example, diplexer  70  of  FIG. 7  may include 5 GHz high-pass filter  68  and 2.4 GHz bandpass filter  69 . If desired, circuitry  20  may include filter  74  between switch  146  and diplexer  70 . Filter  74  may be formed from a 2.4 GHz bandpass filter and, as one example, may help to block 5 GHz transmission signals from path  30  leaking into terminal  152  (and path  42 ) and may help to block radio-frequency telephone signals that have been coupled into antennas  26  via path  102  from propagating to terminal  152  (and path  42 ). With another suitable arrangement, filter  74  may be formed from a 2.4 GHz low-pass filter. 
     Switch  146  may be implemented as part of a larger circuit such as circuit  145 . Circuit  145  may be, for example, an integrated circuit that contains an integrated low-noise radio-frequency input amplifier such as amplifier  121 . 
     Switch  146  may be a two-position switch (as an example). With a two-position configuration, switch  146  may be used to connect terminal  152  to terminal  148  or terminal  150 . Control signals CONTROL may be provided to switch  146  from radio-frequency transceiver  22  to select which of the two positions is used. 
     When it is desired to transmit 2.4 GHz WiFi signals, control signals CONTROL on path  147  may be used to direct switch  146  to connect path  40  to terminal  152 . In this configuration, 2.4 GHz WiFi signals that are transmitted on output path  40  by radio-frequency transceiver circuitry  22  may be routed to diplexer  70 . Signals at 2.4 GHz may be routed from antennas  26  to 2.4 GHz input path  42  by placing switch  146  in position  150  and routing incoming signals to path  42  through low-noise amplifier  121 . 
     Switch  138  may be used to connect diplexer  70  to either path  30  or path  32  depending on the state of one or more control signals. These control signals may be provided to switch  138  from radio-frequency transceiver circuitry  22  over one or more control lines. These control lines and associated control signals are shown as control path  141  and control signal HCONTROL in  FIG. 7 . When diplexer  70  is connected to path  30  (e.g., terminal  144  is connected to terminal  140 ), 5 GHz WiFi signals can be transmitted from radio-frequency transceiver circuitry  22  using one of antennas  26 . When diplexer  70  is connected to path  32  (e.g., terminal  144  is connected to terminal  142 ), 5 GHz WiFi signals that have been received using antennas  26  can be routed to radio-frequency transceiver circuitry  22 . If desired, path  30  may include amplifier  222  to boost the transmission signals on path  30 . 
     With the arrangement shown in  FIG. 7 , device  10  may be able to maximize the airtime of Bluetooth transmissions (because Bluetooth transmission path  44  may be almost continuously coupled to one of the antennas  26 ). In addition, the arrangement shown in  FIG. 7  may facilitate the simultaneous transmission of Bluetooth signals while receiving 5 GHz WiFi signals. If desired, diplexer  70  may include relatively high quality filters to reduce crosstalk from antenna  100  and a GPS antenna in device  10 , to reduce potential insertion losses, and to allow simultaneous transmission operations through transmission line  30  and receiving operations through receiving line  42  (as examples). With one suitable arrangement, filters may be included in path  30  (e.g., the 5 GHz transmission line) to provide harmonic filtering for path  30 . It may be desirable to include relatively robust antennas  26  in the example of  FIG. 7  to reduce the risk of one of the antennas  26  breaking. 
     In the example of  FIG. 8 , circuitry  20  may include a diplexer  70  and switches  154 ,  162 ,  170 , and  178 . Diplexer  70  may convey 2.4 GHz radio-frequency signals between switch  162  and switching circuitry  72  and may convey 5 GHz radio-frequency signals between switch  154  and switching circuitry (as examples). With one suitable arrangement, diplexer  70  of  FIG. 8  may include 5 GHz high-pass filter  68  and 2.4 GHz bandpass filter  69 . If desired, circuitry  20  may include filter  77  between switch  178  and output path  44 . 
     When it is desired to transmit 2.4 GHz WiFi signals, control signals CONTROL on path  163  may be used to direct switch  162  to connect path  40  to terminal  168 . In this configuration, 2.4 GHz WiFi signals that are transmitted on output path  40  by radio-frequency transceiver circuitry  22  may be routed to diplexer  70 . 
     When it is desired to route signals at 2.4 GHz from antennas  26  to 2.4 GHz input path  42 , control signals CONTROL on path  163  and control signals CONTROL on path  171  may be used to direct switch  162  to connect diplexer  70  to terminal  174  of switch  170  and to direct switch  170  to connect terminal  174  to terminal  172 . In this configuration, signals at 2.4 GHz may be routed from antennas  26  to 2.4 GHz input path  42  by placing switch  162  in position  166  and by placing switch  170  in position  174  and routing incoming signals to path  42 . 
     With another suitable arrangement, signals at 2.4 GHz may be routed from antenna  26  to input path  42  through switches  178  and  170 . With this type of arrangement, control signals CONTROL on path  179  and control signals CONTROL on path  171  may be used to direct switch  178  to connect path  62  to switch  170  (e.g., connect terminal  184  to terminal  180 ) and to direct switch  170  to connect terminal  176  to terminal  172 . 
     When it is desired to transmit 2.4 Bluetooth signals, control signals CONTROL on path  179  may be used to direct switch  178  to connect path  44  to path  62  (e.g., to connect terminals  182  and  184 ). In this configuration, 2.4 GHz Bluetooth signals that are transmitted on output path  44  by radio-frequency transceiver circuitry  22  may be routed to antennas  26 . 
     Switch  154  may be used to connect diplexer  70  to either path  30  or  32  depending on the state of one or more control signals. These control signals may be provided to switch  154  from radio-frequency transceiver circuitry  22  over one or more control lines. These control lines and associated control signals are shown as control path  155  and control signal HCONTROL in  FIG. 8 . When diplexer  70  is connected to path  30  (e.g., terminal  156  is connected to terminal  160 ), 5 GHz WiFi signals can be transmitted from radio-frequency transceiver circuitry  22  using one of antennas  26 . When diplexer  70  is connected to path  32  (e.g., terminal  158  is connected to terminal  160 ), 5 GHz WiFi signals that have been received using antennas  26  can be routed to radio-frequency transceiver circuitry  22 . If desired, path  30  may include amplifier  222  to boost the transmission signals on path  30 . 
     In the arrangement shown in  FIG. 8 , it may be desirable to provide antennas  26  that are relatively isolated from each other to reduce potential crosstalk signals between the two antennas  26  during the simultaneous operation of the two antennas  26  (e.g., during the simultaneous transmission of Bluetooth signals on path  44  and the reception of signals on path  30 ). If desired, the switches of  FIG. 8  may be optimized to reduce insertion losses and to reduce the cost to manufacture the switches. As an example, diplexer  70  may include relatively high quality filters to reduce crosstalk between the two antennas  26 , to reduce potential insertion losses, to allow simultaneous transmission operations through transmission line  30  and receiving operations through receiving line  42  (e.g., when receiving line  42  is coupled to the same antenna as line  30 ), and to reduce crosstalk from antenna  100  and a GPS antenna in device  10 . 
     As shown in  FIG. 9 , the arrangement of  FIG. 6  may be modified by utilizing diplexer  70  (rather than diplexer  64 ). Diplexer  70  may include filters  68  and  69 . Filter  68  may be a 5 GHz high-pass filter that passes radio-frequency signals at frequencies above 4.8 GHz or above 4.9 GHz (as an example). Filter  69  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). If desired, filter  76  may not be included in the circuitry  20  of  FIG. 9 . With this type of arrangement, diplexer  70  serves as the primary source of filtering between antennas  26  and circuitry  22 . With one suitable arrangement, diplexer  70  of  FIG. 9  may be a relatively high performance diplexer in order to ensure sufficient filtering. 
     With the arrangement shown in  FIG. 9 , the coexistence of 2.4 GHz WiFi and Bluetooth signals and 5 GHz WiFi signals may not be dependent on the isolation between the two antennas  26  (e.g., there may be relatively poor isolation between each of the two antennas  26  without reducing the ability to support coexistence between 2.4 GHz and 5 GHz signals). In addition, the arrangement of  FIG. 9  may provide redundancy in the event that one of the two antennas  26  breaks or fails (e.g., wireless communications can continue even if one of the two antennas  26  breaks). If desired, diplexer  70  may include relatively high quality filters to reduce insertion losses, to reduce cross talk from cellular telephone antenna  100 , to allow simultaneous transmission of Bluetooth signals over path  44  and reception of 5 GHz WiFi signals over path  32 , and to allow simultaneous transmission of 5 GHz WiFi signals over path  30  and reception of Bluetooth signals over path  42 . With one suitable arrangement, filters may be included in path  30  (e.g., the 5 GHz transmission line) to provide harmonic filtering for path  30 . 
     As shown in  FIG. 10 , circuitry  20  may include filters  86  and  88  and switches  204  and  212 . Filter  86  may be a 2.4 GHz bandpass filter that passes radio-frequency signals in the range of 2.4 to 2.5 GHz (as an example). Filter  88  may be a 5 GHz bandpass filter that passes radio-frequency signals in the range of 4.9 GHz to 6 GHz (as an example). As shown in  FIG. 10 , filter  88  may convey 5 GHz radio-frequency signals between switch  204  and antennas  26  (e.g., path  82 ) while filter  86  may convey 2.4 GHz radio-frequency signals between switch  212  and antennas  26  (e.g., path  62 ). 
     When, for example, antenna  26 A is performing better than antenna  26 B, switching circuitry  72  may be used to switch antenna  26 A into use for wireless transmissions by coupling antenna  26 A to lines carrying transmission signals (e.g., coupling antenna  26 A to path  82  or path  62  depending on which path is currently being used to convey transmission signals) and to switch antenna  26 B into use by coupling antenna  26 B to wireless receivers in circuitry  22  through receiver lines (e.g., coupling antenna  26 B to path  82  or path  62  depending on which path is currently being used to receive signals). When, for example, antenna  26 B is performing better than antenna  26 A, switching circuitry  72  may be used to switch antenna  26 B into use for wireless transmissions by coupling antenna  26 B to lines carrying transmission signals and to switch antenna  26 A into use by coupling antenna  26 A to wireless receivers in circuitry  22  through receiver lines. 
     Switch  212  may be implemented as part of a larger circuit such as circuit  211 . Circuit  211  may be, for example, an integrated circuit that contains an integrated low-noise radio-frequency input amplifier such as amplifier  121 . Components such as these may also be provided using one or more separate devices. The arrangement of  FIG. 10 , in which low-noise amplifier  121  and switch  212  are implemented as parts of a common integrated circuit  211  is merely illustrative. 
     Switch  212  may be a three-position switch (as an example). With a three-position configuration, switch  212  may be used to connect terminal  214  to terminal  216 , terminal  218 , or terminal  220 . Control signals CONTROL may be provided to switch  120  from radio-frequency transceiver  22  to select which of the three positions is used. 
     When it is desired to transmit 2.4 GHz WiFi signals, control signals CONTROL on path  213  may be used to direct switch  214  to connect path  40  to terminal  214 . In this configuration, 2.4 GHz WiFi signals that are transmitted on output path  40  by radio-frequency transceiver circuitry  22  may be routed to filter  86  and terminal  50  of circuitry  72 . Signals at 2.4 GHz may be routed from antennas  26  to 2.4 GHz input path  42  by placing switch  212  in position  218  and routing incoming signals to path  42  through low-noise amplifier  121 . When it is desired to transmit 2.4 Bluetooth signals, control signals CONTROL on path  213  may be used to direct switch  212  to connect path  44  to terminal  214 . In this configuration, 2.4 GHz Bluetooth signals that are transmitted on output path  44  by radio-frequency transceiver circuitry  22  may be routed to antennas  26 . 
     Switch  204  may be used to connect filter  88  (e.g., path  82  and terminal  48  of circuitry  72 ) to either path  30  or path  32  depending on the state of one or more control signals. These control signals may be provided to switch  204  from radio-frequency transceiver circuitry  22  over one or more control lines. These control lines and associated control signals are shown as control path  205  and control signal HCONTROL in  FIG. 10 . When filter  88  is connected to path  30  (e.g., terminal  208  is connected to terminal  206 ), 5 GHz WiFi signals can be transmitted from radio-frequency transceiver circuitry  22  using one of antennas  26 . When filter  88  is connected to path  32  (e.g., terminal  206  is connected to terminal  210 ), 5 GHz WiFi signals that have been received using antennas  26  can be routed to radio-frequency transceiver circuitry  22 . If desired, path  30  may include amplifier  222  to boost the transmission signals on path  30 . 
     In the arrangement of  FIG. 10 , the use of filters  86  and  88  may allow coexistence of 5 GHz signals, 2.4 GHz signals, cellular telephone signals, and GPS signals by effectively eliminating crosstalk signals (even if the two antennas  26  are poorly isolated and/or terminals  48  and  50  of switch  72  are poorly isolated). In addition, the filters of  FIG. 10  may effectively filter out any harmonics on the 5 GHz transmission line  30 . With one suitable arrangement, filter  88  may be formed from a relatively high quality filter to reduce any insertion loss penalties associated with conveying signals from 5 GHz transmission path  30  to switch  72 . In addition, it may be desirable to include relatively robust antennas  26  in the example of  FIG. 10  to reduce the risk of one of the antennas  26  breaking. 
     Any of the illustrative architectures of  FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10  can be used to simultaneously implement antenna diversity and antenna sharing functions. Antenna diversity may be implemented by using switching circuitry  72  or switching circuitry  73  to switch antennas  26 A or  26 B into use as appropriate to optimize signals strength. Antenna sharing may be implemented by using switching circuitry such as circuitry  112 ,  120 ,  130 ,  138 ,  146 ,  154 ,  162 ,  170 ,  178 ,  204 , and  212  and associated filter circuitry to selectively route 2.4 GHz and 5 GHz signals between the input-output ports associated with circuitry  22  and antennas  26 . The use of this antenna sharing circuitry allows a single antenna structure (i.e., the diversity antenna implemented using antennas  26 A and  26 B) to be used for both 5 GHz and 2.4 GHz signals and to be used for both WiFi and Bluetooth traffic. Antennas  26 A and  26 B may each be implemented using multiband designs that cover both the 2.4 GHz and 5 GHz bands. 
     Because of the potential close proximity of other wireless components in housing  12  of device  10  such as cellular telephone transceiver  98  and cellular telephone antenna  100 , there is a potential for undesirable radio-frequency interference with the 2.4 GHz and 5 GHz operations of circuitry  22 . In particular, when a user is operating device  10  so that cellular telephone transceiver  98  is active, radio-frequency telephone signals from transceiver  98  may be coupled into antennas  26  via path  102 . Even though antennas  26  are not nominally designed to handle cellular telephone frequencies, the close proximity of antenna  100  to antennas  26  may allow a non-zero amount of cellular telephone signals to be introduced onto antennas  26 . These signals may be effectively eliminated using filtering circuitry such as the filtering circuitry of diplexers  63 ,  64 ,  65 , and  70  and filtering circuitry  74 ,  76 ,  77 ,  86 , and  88  (as examples). In particular, the use of diplexers and filtering circuitry may reduce cellular crosstalk by 10-20 dB (for signals at frequencies from about 1800 MHz to 2100 MHz) to 50 dB (for signals at frequencies of about 850 MHz to 900 MHz). 
     Device  10  can use circuitry  20  to support various operating modes in which 5 GHz WiFi signals are conveyed over antennas  26  while simultaneously handling 2.4 GHz signals. For example, 5 GHz WiFi signals may be transmitted, while simultaneously transmitting and/or receiving 2.4 GHz signals (e.g., for Bluetooth and/or WiFi). WiFi signals at 5 GHz may be received, while simultaneously receiving 2.4 GHz signals (e.g., for Bluetooth and/or WiFi). WiFi operations at 5 GHz may also be supported simultaneously with 2.4 GHz WiFi transmission and 2.4 GHz Bluetooth transmission operations. For example, 5 GHz WiFi signals may be transmitted, while simultaneously transmitting 2.4 GHz WiFi signals. WiFi signals at 5 GHz may also be transmitted, while simultaneously transmitting 2.4 GHz Bluetooth signals. WiFi 5 GHz signals may be received, while simultaneously transmitting 2.4 GHz WiFi signals. WiFi signals at 5 GHz may also be received, while simultaneously transmitting 2.4 GHz Bluetooth signals. If desired, radio-frequency transceiver circuitry  22  with different input and output ports may be used to support additional operating modes. The arrangements of  FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10  are shown as examples. During all of these modes, circuitry  22  may control antenna diversity switching circuitry  72  and/or antenna diversity switching circuitry  73  in real time to implement an antenna diversity scheme using antennas  26 A and  26 B. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20090409
Publication Date: 20120626
Grant Date: 20120626
Priority Date: 20090409
Inventors: LUM NICHOLAS W.
SANGUINETTI LOUIE J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/0057", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/0057", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 42934316