PATENT DOCUMENT

Publication Number: US-10651555-B2
Application Number: US-201715650627-A
Country: US
Kind Code: B2

Title: Multi-band millimeter wave patch antennas

Abstract:
An electronic device may be provided with wireless circuitry including first and second patch antennas. The first patch antenna may include a first resonating element formed over a ground plane. The second patch antenna may include a second resonating element over the first resonating element. A cross-shaped parasitic element may be formed over the second resonating element. First and second feed terminals may be coupled to the second resonating element. An opening may be formed in the first resonating element. First and second transmission lines may be coupled to the first and second feed terminals through the opening. The cross-shaped parasitic element may include arms that overlap the first and second feed terminals. The first resonating element may cover first frequencies between 10 GHz and 300 GHz and the second resonating element may cover second frequencies that are higher than the first frequencies.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a stacked dielectric substrate having a first layer, a second layer, a third layer, a fourth layer, and a fifth layer, the second layer being interposed between the first and third layers and the fourth layer being interposed between the fifth and first layers; 
 first metal traces on the first layer, wherein the first metal traces form a first antenna resonating element for a first antenna that handles antenna signals at a first frequency that is greater than 10 GHz; 
 second metal traces on the second layer, wherein the second metal traces form a second antenna resonating element for a second antenna that handles antenna signals at a second frequency that is higher than the first frequency; 
 third metal traces on the third layer that form a parasitic antenna resonating element for the second antenna; 
 fourth metal traces on the fourth layer that form an antenna ground, wherein at least one slot is formed in the fourth metal traces; 
 a first transmission line formed from fifth metal traces on the fifth layer that are coupled to the first metal traces through the fourth layer, the at least one slot, and the first layer; and 
 a second transmission line formed from sixth metal traces on the fifth layer that are coupled to the second metal traces through the fourth layer, the at least one slot, the first layer, an opening in the first metal traces, and the second layer. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the first layer is interposed between the fourth and second layers, and the antenna ground serves as an antenna ground for the first and second antennas. 
     
     
       3. The electronic device defined in  claim 2 , wherein the first antenna comprises a first antenna feed having a first feed terminal on the first metal traces and the second antenna comprises a second antenna feed having a second feed terminal on the second metal traces, the first transmission line is coupled to the first feed terminal on the first metal traces, and the second transmission line is coupled to the second feed terminal on the second metal traces through the opening in the first metal traces. 
     
     
       4. The electronic device defined in  claim 3 , wherein the first antenna further comprises a third antenna feed having a third feed terminal on the first metal traces, the electronic device further comprising:
 a third transmission line coupled to the third feed terminal on the first metal traces. 
 
     
     
       5. The electronic device defined in  claim 4 , wherein the second antenna further comprises a fourth antenna feed having a fourth feed terminal on the second metal traces and an additional opening is formed in the first metal traces, the electronic device further comprising:
 a fourth transmission line coupled to the fourth feed terminal on the second metal traces through the additional opening. 
 
     
     
       6. The electronic device defined in  claim 4 , wherein the opening has first and second arms extending along a first longitudinal axis and third and fourth arms extending along a second longitudinal axis that is oriented at a non-parallel angle with respect to the first longitudinal axis, and the first arm of the opening is interposed between the first and third feed terminals on the first metal traces. 
     
     
       7. The electronic device defined in  claim 6 , wherein the second antenna further comprises a fourth antenna feed having a fourth feed terminal on the second metal traces, the electronic device further comprising:
 a fourth transmission line coupled to the fourth feed terminal on the second metal traces through a selected one of the first and second arms of the opening in the first metal traces, wherein the second transmission line is coupled to the second feed terminal on the second metal traces through a selected one of the third and fourth arms of the opening in the first metal traces. 
 
     
     
       8. The electronic device defined in  claim 1 , wherein the parasitic antenna resonating element comprises first and second arms that extend along a first longitudinal axis and third and fourth arms that extend along a second longitudinal axis that is oriented at a non-parallel angle with respect to the first longitudinal axis. 
     
     
       9. The electronic device defined in  claim 8 , wherein the first metal traces comprise a metal patch having first, second, third, and fourth edges, the first edge is parallel to the second edge, the third edge is parallel to the fourth edge, the third and fourth edges extend between the first and second edges at non-parallel angles with respect to the first edge, the first longitudinal axis of the parasitic antenna resonating element is extends approximately parallel to the first and second edges of the metal patch, and the second longitudinal axis of the parasitic antenna resonating element extends approximately parallel to the third and fourth edges of the metal patch. 
     
     
       10. The electronic device defined in  claim 8 , wherein the second antenna comprises a third antenna feed having a third feed terminal on the second metal traces, the first arm of the parasitic antenna resonating element overlaps the second feed terminal on the second metal traces, and the third arm of the parasitic antenna resonating element overlaps the third feed terminal on the second metal traces. 
     
     
       11. The electronic device defined in  claim 1 , wherein the at least one slot comprises first and second slots, the fifth metal traces are coupled to the first metal traces through the first slot, and the sixth metal traces are coupled to the second metal traces through the second slot. 
     
     
       12. Antenna structures, comprising:
 an antenna ground; 
 a first patch antenna resonating element over the antenna ground; 
 first and second antenna feed terminals coupled to the first patch antenna resonating element; 
 a second patch antenna resonating element over the first patch antenna resonating element; 
 a cross-shaped opening in the first patch antenna resonating element, the cross-shaped opening having first and second arms, one of which is interposed between the first and second antenna feed terminals; 
 a first transmission line coupled to the first patch antenna resonating element; 
 a second transmission line coupled to the second patch antenna resonating element through the cross-shaped opening in the first patch antenna resonating element; and 
 a cross-shaped parasitic antenna resonating element over the second patch antenna resonating element, wherein first and second arms of the cross-shaped parasitic antenna resonating element overlap the first and second arms of the cross-shaped opening in the first patch antenna resonating element respectively. 
 
     
     
       13. The antenna structures defined in  claim 12 , further comprising:
 a third transmission line, wherein the first transmission line is coupled to the first antenna feed terminal, the third transmission line is coupled to the second antenna feed terminal. 
 
     
     
       14. The antenna structures defined in  claim 13 , further comprising:
 third and fourth antenna feed terminals coupled to the second patch antenna resonating element; and 
 a fourth transmission line, wherein the second transmission line is coupled to the third antenna feed terminal through the cross-shaped opening and the fourth transmission line is coupled to the fourth antenna feed terminal through the cross-shaped opening. 
 
     
     
       15. The antenna structures defined in  claim 12 , further comprising:
 a third antenna feed terminal coupled to the antenna ground; 
 a cross-shaped parasitic antenna resonating element over the second patch antenna resonating element; 
 a third patch antenna resonating element over the antenna ground; and 
 a non-radiative parasitic element formed over the antenna ground and between the first patch antenna resonating element and the third patch antenna resonating element. 
 
     
     
       16. Antenna structures, comprising:
 an antenna ground; 
 a first conductive patch over the antenna ground; 
 an antenna feed having a first antenna feed terminal coupled to the first conductive patch and a second antenna feed terminal coupled to the antenna ground; 
 a second conductive patch over the first conductive patch; 
 a third conductive patch over the antenna ground; 
 a fourth conductive patch over the third conductive patch; 
 a first parasitic element formed over the antenna ground and between the first conductive patch and the third conductive patch, the first parasitic element being configured to reduce electromagnetic coupling between the first and third conductive patches; and 
 a second parasitic element formed over the first parasitic element and between the second conductive patch and the fourth conductive patch, the second parasitic element being configured to reduce electromagnetic coupling between the second and fourth conductive patches. 
 
     
     
       17. The antenna structures defined in  claim 16 , further comprising:
 a third antenna feed terminal coupled to the first conductive patch; 
 an opening in the first conductive patch, the opening having a portion that is between the first and third antenna feed terminals; 
 a first transmission line coupled to the first conductive patch; and 
 a second transmission line coupled to the second conductive patch through the opening in the first conductive patch. 
 
     
     
       18. The antenna structures defined in  claim 17  wherein the opening in the first conductive patch is a cross-shaped opening and the portion of the opening is an arm of the cross-shaped opening. 
     
     
       19. The antenna structures defined in  claim 16 , wherein the first conductive patch is formed on a first substrate layer, the first parasitic element is formed on the first substrate layer, the second conductive patch is formed on a second substrate layer, and the second parasitic element is formed on the second substrate layer. 
     
     
       20. The antenna structures defined in  claim 16 , wherein the first parasitic element has first and second opposing edges, the first edge being an edge of the first parasitic element closest to the first conductive patch and being separated from the first conductive patch by a first distance, and the second edge being an edge of the first parasitic element closest to the third conductive patch and being separated from the third conductive patch by a second distance greater than the first distance.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications circuitry. 
     Electronic devices often include wireless communications circuitry. For example, cellular telephones, computers, and other devices often contain antennas and wireless transceivers for supporting wireless communications. 
     It may be desirable to support wireless communications in millimeter wave and centimeter wave communications bands. Millimeter wave communications, which are sometimes referred to as extremely high frequency (EHF) communications, and centimeter wave communications involve communications at frequencies of about 10-300 GHz. Operation at these frequencies may support high bandwidths but may raise significant challenges. For example, millimeter wave communications are often line-of-sight communications and can be characterized by substantial attenuation during signal propagation. 
     It would therefore be desirable to be able to provide electronic devices with improved wireless communications circuitry such as communications circuitry that supports communications at frequencies greater than 10 GHz. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antenna structures and transceiver circuitry such as millimeter wave transceiver circuitry. Antenna structures in the wireless circuitry may include co-located patch antennas that are organized in a phased antenna array. 
     The antenna structures may include a first patch antenna and a second patch antenna formed on a dielectric substrate. The dielectric substrate may include multiple dielectric layers. A ground plane may be formed on a first dielectric layer. The first patch antenna may include a first patch antenna resonating element formed from metal traces on a second dielectric layer. The second patch antenna may include a second patch antenna resonating element over the first patch antenna resonating element. The second patch antenna resonating element may be formed from metal traces on a third dielectric layer. A cross-shaped parasitic antenna resonating element may be formed over the second patch antenna resonating element and on a fourth dielectric layer. 
     The first patch antenna may be fed using a first transmission line coupled to a first feed terminal and a second transmission line coupled to a second feed terminal on the first patch antenna resonating element. Third and fourth feed terminals may be coupled to the second patch antenna resonating element. An opening such as a cross-shaped opening may be formed in the first patch antenna resonating element and may be configured to enhance isolation between the first and second feed terminals on the first patch antenna resonating element. The second patch antenna may be fed using third and fourth transmission lines coupled to the third and fourth feed terminals through the opening in the first patch antenna resonating element. 
     The cross-shaped parasitic antenna resonating element may have a first conductive arm that extends along a first longitudinal axis and a second conductive arm that extends along the second longitudinal axis that is oriented at a non-parallel angle with respect to the first longitudinal axis. The first conductive arm may overlap the third feed terminal and the second conductive arm may overlap the fourth feed terminal on the second patch antenna resonating element. The arms of the cross-shaped parasitic antenna resonating element and the cross-shaped opening in the first patch antenna resonating element may be oriented at parallel angles with respect to the edges of the second patch antenna resonating element. 
     The first patch antenna may convey antenna signals (e.g., centimeter wave signals) in a first frequency band such as a frequency band between 27.5 GHz and 28.5 GHz. The second patch antenna may convey antenna signals (e.g., millimeter wave signals) in a second frequency band such as a frequency band between 57 GHz and 71 GHz. Forming the second patch antenna resonating element over the first patch antenna resonating element may minimize the amount of space required for covering the first and second frequency bands within the electronic device. 
    
    
     
       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. 
         FIG. 2  is a schematic diagram of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment. 
         FIG. 3  is a rear perspective view of an illustrative electronic device showing illustrative locations at which antennas for communications at frequencies greater than 10 GHz may be located in accordance with an embodiment. 
         FIG. 4  is a diagram of an illustrative transceiver circuit and antenna in accordance with an embodiment. 
         FIG. 5  is a perspective view of an illustrative patch antenna in accordance with an embodiment. 
         FIG. 6  is a perspective view of an illustrative patch antenna with dual ports in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of illustrative multi-band antenna structures including co-located patch antennas and a parasitic antenna resonating element in accordance with an embodiment. 
         FIG. 8  is a top-down view of illustrative multi-band antenna structures including co-located patch antennas and a parasitic antenna resonating element in accordance with an embodiment. 
         FIG. 9  is a perspective view of illustrative multi-band antenna structures including co-located patch antennas and a parasitic antenna resonating element in accordance with an embodiment. 
         FIGS. 10 and 11  are top-down views of a phased antenna array including antennas of the type shown in  FIGS. 5-9  and non-radiative elements in accordance with an embodiment. 
         FIG. 12  is a graph of antenna efficiency for illustrative multi-band antenna structures of the type shown in  FIGS. 5-11  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG. 1  may contain wireless circuitry. The wireless circuitry may include one or more antennas. The antennas may include phased antenna arrays that are used for handling millimeter wave and centimeter wave communications. Millimeter wave communications, which are sometimes referred to as extremely high frequency (EHF) communications, involve signals at 60 GHz or other frequencies between about 30 GHz and 300 GHz. Centimeter wave communications involve signals at frequencies between about 10 GHz and 30 GHz. If desired, device  10  may also contain wireless communications circuitry for handling satellite navigation system signals, cellular telephone signals, local wireless area network signals, near-field communications, light-based wireless communications, or other wireless communications. 
     Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a virtual or augmented reality headset device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, a wireless access point or base station, a desktop computer, a keyboard, a gaming controller, a computer mouse, a mousepad, a trackpad or touchpad, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG. 1 , device  10  is a portable device such as a cellular telephone, media player, tablet computer, or other portable computing device. Other configurations may be used for device  10  if desired. The example of  FIG. 1  is merely illustrative. 
     As shown in  FIG. 1 , device  10  may include a display such as display  14 . Display  14  may be mounted in a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, sapphire, or other transparent dielectric. Openings may be formed in the display cover layer. For example, openings may be formed in the display cover layer to accommodate one or more buttons, sensor circuitry such as a fingerprint sensor or light sensor, ports such as a speaker port or microphone port, etc. Openings may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, charging port, etc.). Openings in housing  12  may also be formed for audio components such as a speaker and/or a microphone. 
     Antennas may be mounted in housing  12 . If desired, some of the antennas (e.g., antenna arrays that may implement beam steering, etc.) may be mounted under an inactive border region of display  14  (see, e.g., illustrative antenna locations  50  of  FIG. 1 ). Display  14  may contain an active area with an array of pixels (e.g., a central rectangular portion). Inactive areas of display  14  are free of pixels and may form borders for the active area. If desired, antennas may also operate through dielectric-filled openings in the rear of housing  12  or elsewhere in device  10 . 
     To avoid disrupting communications when an external object such as a human hand or other body part of a user blocks one or more antennas, antennas may be mounted at multiple locations in housing  12 . Sensor data such as proximity sensor data, real-time antenna impedance measurements, signal quality measurements such as received signal strength information, and other data may be used in determining when one or more antennas is being adversely affected due to the orientation of housing  12 , blockage by a user&#39;s hand or other external object, or other environmental factors. Device  10  can then switch one or more replacement antennas into use in place of the antennas that are being adversely affected. 
     Antennas may be mounted at the corners of housing  12  (e.g., in corner locations  50  of  FIG. 1  and/or in corner locations on the rear of housing  12 ), along the peripheral edges of housing  12 , on the rear of housing  12 , under the display cover glass or other dielectric display cover layer that is used in covering and protecting display  14  on the front of device  10 , under a dielectric window on a rear face of housing  12  or the edge of housing  12 , or elsewhere in device  10 . 
     A schematic diagram showing illustrative components that may be used in device  10  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include storage and processing circuitry such as control circuitry  14 . Control circuitry  14  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  14  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processor integrated circuits, application specific integrated circuits, etc. 
     Control circuitry  14  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, control circuitry  14  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  14  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other WPAN protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols, etc. 
     Device  10  may include input-output circuitry  16 . Input-output circuitry  16  may include input-output devices  18 . Input-output devices  18  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  may include user interface devices, data port devices, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, accelerometers or other components that can detect motion and device orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components. 
     Input-output circuitry  16  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications 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  40 , transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include transceiver circuitry  20  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  22 ,  24 ,  26 , and  28 . 
     Transceiver circuitry  24  may be wireless local area network (WLAN) transceiver circuitry. Transceiver circuitry  24  may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and may handle the 2.4 GHz Bluetooth® communications band. 
     Circuitry  34  may use cellular telephone transceiver circuitry  26  for handling wireless communications in frequency ranges such as a communications band from 700 to 960 MHz, a communications band from 1710 to 2170 MHz, and a communications from 2300 to 2700 MHz or other communications bands between 700 MHz and 4000 MHz or other suitable frequencies (as examples). Circuitry  26  may handle voice data and non-voice data. 
     Millimeter wave transceiver circuitry  28  (sometimes referred to as extremely high frequency (EHF) transceiver circuitry  28  or transceiver circuitry  28 ) may support communications at frequencies between about 10 GHz and 300 GHz. For example, transceiver circuitry  28  may support communications in Extremely High Frequency (EHF) or millimeter wave communications bands between about 30 GHz and 300 GHz and/or in centimeter wave communications bands between about 10 GHz and 30 GHz (sometimes referred to as Super High Frequency (SHF) bands). As examples, transceiver circuitry  28  may support communications in an IEEE K communications band between about 18 GHz and 27 GHz, a K a  communications band between about 26.5 GHz and 40 GHz, a K u  communications band between about 12 GHz and 18 GHz, a V communications band between about 40 GHz and 75 GHz, a W communications band between about 75 GHz and 110 GHz, or any other desired frequency band between approximately 10 GHz and 300 GHz. If desired, circuitry  28  may support IEEE 802.11ad communications at 60 GHz and/or 5 th  generation mobile networks or 5 th  generation wireless systems (5G) communications bands between 27 GHz and 90 GHz. If desired, circuitry  28  may support communications at multiple frequency bands between 10 GHz and 300 GHz such as a first band from 27.5 GHz to 28.5 GHz, a second band from 37 GHz to 41 GHz, and a third band from 57 GHz to 71 GHz, or other communications bands between 10 GHz and 300 GHz. Circuitry  28  may be formed from one or more integrated circuits (e.g., multiple integrated circuits mounted on a common printed circuit in a system-in-package device, one or more integrated circuits mounted on different substrates, etc.). While circuitry  28  is sometimes referred to herein as millimeter wave transceiver circuitry  28 , millimeter wave transceiver circuitry  28  may handle communications at any desired communications bands at frequencies between 10 GHz and 300 GHz (e.g., in millimeter wave communications bands, centimeter wave communications bands, etc.). 
     Wireless communications circuitry  34  may include satellite navigation system circuitry such as Global Positioning System (GPS) receiver circuitry  22  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data (e.g., GLONASS signals at 1609 MHz). Satellite navigation system signals for receiver  22  are received from a constellation of satellites orbiting the earth. 
     In satellite navigation system links, cellular telephone links, and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. In WiFi® and Bluetooth® links at 2.4 and 5 GHz and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. Extremely high frequency (EHF) wireless transceiver circuitry  28  may convey signals over these short distances that travel between transmitter and receiver over a line-of-sight path. To enhance signal reception for millimeter and centimeter wave communications, phased antenna arrays and beam steering techniques may be used (e.g., schemes in which antenna signal phase and/or magnitude for each antenna in an array is adjusted to perform beam steering). Antenna diversity schemes may also be used to ensure that the antennas that have become blocked or that are otherwise degraded due to the operating environment of device  10  can be switched out of use and higher-performing antennas used in their place. 
     Wireless communications circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  34  may include circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc. 
     Antennas  40  in wireless communications circuitry  34  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, monopoles, dipoles, helical antenna structures, Yagi (Yagi-Uda) antenna structures, hybrids of these designs, etc. If desired, one or more of antennas  40  may be cavity-backed antennas. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link antenna. Dedicated antennas may be used for receiving satellite navigation system signals or, if desired, antennas  40  can be configured to receive both satellite navigation system signals and signals for other communications bands (e.g., wireless local area network signals and/or cellular telephone signals). Antennas  40  can one or more antennas such as antennas arranged in one or more phased antenna arrays for handling millimeter and centimeter wave communications. 
     Transmission line paths may be used to route antenna signals within device  10 . For example, transmission line paths may be used to couple antenna structures  40  to transceiver circuitry  20 . Transmission lines in device  10  may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, transmission lines formed from combinations of transmission lines of these types, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired. 
     In devices such as handheld devices, the presence of an external object such as the hand of a user or a table or other surface on which a device is resting has a potential to block wireless signals such as millimeter wave signals. Accordingly, it may be desirable to incorporate multiple antennas or phased antenna arrays into device  10 , each of which is placed in a different location within device  10 . With this type of arrangement, an unblocked antenna or phased antenna array may be switched into use. In scenarios where a phased antenna array is formed in device  10 , once switched into use, the phased antenna array may use beam steering to optimize wireless performance. Configurations in which antennas from one or more different locations in device  10  are operated together may also be used. 
       FIG. 3  is a perspective view of electronic device  10  showing illustrative locations  50  on the rear of housing  12  in which antennas  40  (e.g., single antennas and/or phased antenna arrays for use with wireless circuitry  34  such as wireless transceiver circuitry  28 ) may be mounted in device  10 . Antennas  40  may be mounted at the corners of device  10 , along the edges of housing  12  such as edge  12 E, on upper and lower portions of rear housing portion (wall)  12 R, in the center of rear housing wall  12 R (e.g., under a dielectric window structure or other antenna window in the center of rear housing  12 R), at the corners of rear housing wall  12 R (e.g., on the upper left corner, upper right corner, lower left corner, and lower right corner of the rear of housing  12  and device  10 ), etc. 
     In configurations in which housing  12  is formed entirely or nearly entirely from a dielectric, antennas  40  may transmit and receive antenna signals through any suitable portion of the dielectric. In configurations in which housing  12  is formed from a conductive material such as metal, regions of the housing such as slots or other openings in the metal may be filled with plastic or other dielectric. Antennas  40  may be mounted in alignment with the dielectric in the openings. These openings, which may sometimes be referred to as dielectric antenna windows, dielectric gaps, dielectric-filled openings, dielectric-filled slots, elongated dielectric opening regions, etc., may allow antenna signals to be transmitted to external equipment from antennas  40  mounted within the interior of device  10  and may allow internal antennas  40  to receive antenna signals from external equipment. In another suitable arrangement, antennas  40  may be mounted on the exterior of conductive portions of housing  12 . 
     In devices with phased antenna arrays, circuitry  34  may include gain and phase adjustment circuitry that is used in adjusting the signals associated with each antenna  40  in an array (e.g., to perform beam steering). Switching circuitry may be used to switch desired antennas  40  into and out of use. Each of locations  50  may include multiple antennas  40  (e.g., a set of three antennas or more than three or fewer than three antennas in a phased antenna array) and, if desired, one or more antennas from one of locations  50  may be used in transmitting and receiving signals while using one or more antennas from another of locations  50  in transmitting and receiving signals. 
     A schematic diagram of an antenna  40  coupled to transceiver circuitry  20  (e.g., transceiver circuitry  28 ) is shown in  FIG. 4 . As shown in  FIG. 4 , radio-frequency transceiver circuitry  20  may be coupled to antenna feed  100  of antenna  40  using transmission line  64 . Antenna feed  100  may include a positive antenna feed terminal such as positive antenna feed terminal  96  and may have a ground antenna feed terminal such as ground antenna feed terminal  98 . Transmission line  64  may be formed form metal traces on a printed circuit or other conductive structures and may have a positive transmission line signal path such as path  91  that is coupled to terminal  96  and a ground transmission line signal path such as path  94  that is coupled to terminal  98 . Transmission line paths such as path  64  may be used to route antenna signals within device  10 . For example, transmission line paths may be used to couple antenna structures such as one or more antennas in an array of antennas to transceiver circuitry  20 . Transmission lines in device  10  may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, transmission lines formed from combinations of transmission lines of these types, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within transmission line  64  and/or circuits such as these may be incorporated into antenna  40  if desired (e.g., to support antenna tuning, to support operation in desired frequency bands, etc.). 
     Device  10  may contain multiple antennas  40 . The antennas may be used together or one of the antennas may be switched into use while other antenna(s) are switched out of use. If desired, control circuitry  14  may be used to select an optimum antenna to use in device  10  in real time and/or to select an optimum setting for adjustable wireless circuitry associated with one or more of antennas  40 . Antenna adjustments may be made to tune antennas to perform in desired frequency ranges, to perform beam steering with a phased antenna array, and to otherwise optimize antenna performance. Sensors may be incorporated into antennas  40  to gather sensor data in real time that is used in adjusting antennas  40 . 
     In some configurations, antennas  40  may be arranged in one or more antenna arrays (e.g., phased antenna arrays to implement beam steering functions). For example, the antennas that are used in handling millimeter and centimeter wave signals for wireless transceiver circuits  28  may be implemented as phased antenna arrays. The radiating elements in a phased antenna array for supporting millimeter and centimeter wave communications may be patch antennas, dipole antennas, dipole antennas with directors and reflectors in addition to dipole antenna resonating elements (sometimes referred to as Yagi antennas or beam antennas), or other suitable antenna elements. Transceiver circuitry can be integrated with the phased antenna arrays to form integrated phased antenna array and transceiver circuit modules. 
     An illustrative patch antenna is shown in  FIG. 5 . As shown in  FIG. 5 , patch antenna  40  may have a patch antenna resonating element  104  that is separated from and parallel to a ground plane such as antenna ground plane  92 . Positive antenna feed terminal  96  may be coupled to patch antenna resonating element  104 . Ground antenna feed terminal  98  may be coupled to ground plane  92 . If desired, conductive path  88  may be used to couple terminal  96 ′ to terminal  96  so that antenna  40  is fed using a transmission line with a positive conductor coupled to terminal  96 ′ and thus terminal  96 . If desired, path  88  may be omitted. Other types of antenna feed arrangements may be used if desired. The illustrative feeding configuration of  FIG. 5  is merely illustrative. 
     As shown in  FIG. 5 , patch antenna resonating element  104  may lie within a plane such as the X-Y plane of  FIG. 5  (e.g., the lateral surface area of element  104  may lie in the X-Y plane). Patch antenna resonating element  104  may sometimes be referred to herein as patch  104 , patch element  104 , patch resonating element  104 , or resonating element  104 . Ground  92  may line within a plane that is parallel to the plane of patch  104 . Patch  104  and ground  92  may therefore lie in separate parallel planes that are separated by a distance H. Patch  104  and ground  92  may be formed from conductive traces patterned on a dielectric substrate such as a rigid or flexible printed circuit board substrate, metal foil, stamped sheet metal, electronic device housing structures, or any other desired conductive structures. The length of the sides of patch  104  may be selected so that antenna  40  resonates at a desired operating frequency. For example, the sides of element  104  may each have a length L 0  that is approximately equal to half of the wavelength (e.g., within 15% of half of the wavelength) of the signals conveyed by antenna  40  (e.g., in scenarios where patch element  104  is substantially square). 
     The example of  FIG. 5  is merely illustrative. Patch  104  may have a square shape in which all of the sides of patch  104  are the same length or may have a different rectangular shape. If desired, patch  104  and ground  92  may have different shapes and orientations (e.g., planar shapes, curved patch shapes, patch shapes with non-rectangular outlines, shapes with straight edges such as squares, shapes with curved edges such as ovals and circles, shapes with combinations of curved and straight edges, etc.). In scenarios where patch  104  is non-rectangular, patch  104  may have a side or a maximum lateral dimension that is approximately equal to (e.g., within 15% of) half of the wavelength of operation, for example. 
     To enhance the polarizations handled by patch antenna  40 , antenna  40  may be provided with multiple feeds. An illustrative patch antenna with multiple feeds is shown in  FIG. 6 . As shown in  FIG. 6 , antenna  40  may have a first feed at antenna port P 1  that is coupled to transmission line  64 - 1  and a second feed at antenna port P 2  that is coupled to transmission line  64 - 2 . The first antenna feed may have a first ground feed terminal coupled to ground  92  and a first positive feed terminal  96 -P 1  coupled to patch  104 . The second antenna feed may have a second ground feed terminal coupled to ground  92  and a second positive feed terminal  96 -P 2  on patch  104 . 
     Patch  104  may have a rectangular shape with a first pair of edges running parallel to dimension Y and a second pair of perpendicular edges running parallel to dimension X, for example. The length of patch  104  in dimension Y is L 1  and the length of patch  104  in dimension X is L 2 . With this configuration, antenna  40  may be characterized by orthogonal polarizations. 
     When using the first antenna feed associated with port P 1 , antenna  40  may transmit and/or receive antenna signals in a first communications band at a first frequency (e.g., a frequency at which one-half of the corresponding wavelength is approximately equal to dimension L 1 ). These signals may have a first polarization (e.g., the electric field E 1  of antenna signals  102  associated with port P 1  may be oriented parallel to dimension Y). When using the antenna feed associated with port P 2 , antenna  40  may transmit and/or receive antenna signals in a second communications band at a second frequency (e.g., a frequency at which one-half of the corresponding wavelength is approximately equal to dimension L 2 ). These signals may have a second polarization (e.g., the electric field E 2  of antenna signals  102  associated with port P 2  may be oriented parallel to dimension X so that the polarizations associated with ports P 1  and P 2  are orthogonal to each other). In scenarios where patch  104  is square (e.g., length L 1  is equal to length L 2 ), ports P 1  and P 2  may cover the same communications band. In scenarios where patch  104  is rectangular, ports P 1  and P 2  may cover different communications bands if desired. During wireless communications using device  10 , device  10  may use port P 1 , port P 2 , or both port P 1  and P 2  to transmit and/or receive signals (e.g., millimeter wave signals). 
     The example of  FIG. 6  is merely illustrative. Patch  104  may have a square shape in which all of the sides of patch  104  are the same length or may have a rectangular shape in which length L 1  is different from length L 2 . In general, patch  104  and ground  92  may have different shapes and orientations (e.g., planar shapes, curved patch shapes, patch element shapes with non-rectangular outlines, shapes with straight edges such as squares, shapes with curved edges such as ovals and circles, shapes with combinations of curved and straight edges, etc.). In scenarios where patch  104  is non-rectangular, patch  104  may have a side or a maximum lateral dimension (e.g., a longest side) that is approximately equal to (e.g., within 15% of) half of the wavelength of operation, for example. 
     Antennas  40  such as single-polarization patch antennas of the type shown in  FIG. 5  and/or dual-polarization patch antennas of the type shown in  FIG. 6  may be arranged within a corresponding phased antenna array in device  10  if desired. In practice, it may be desirable for antennas  40  within device  10  to be able to provide coverage in multiple communications bands between 10 GHz and 300 GHz. In one suitable arrangement, a first antenna  40  may provide coverage in a first communications band between 10 GHz and 300 GHz whereas a second antenna  40  provides coverage in a second communications band between 10 GHz and 300 GHz. As examples, the communications bands may include millimeter and/or centimeter wave frequencies from 27.5 GHz to 28.5 GHz, from 26 GHz to 30 GHz, from 20 to 36 GHz, from 37 GHz to 41 GHz, from 36 GHz to 42 GHz, from 30 GHz to 56 GHz, from 57 GHz to 71 GHz, from 58 GHz to 63 GHz, from 59 GHz to 61 GHz, from 42 GHz to 71 GHz, or any other desired bands of frequencies between 10 GHz and 300 GHz. As one example, the first communications band may include a 5 th  generation mobile networks or 5 th  generation wireless systems (5G) communication band between 27.5 GHz and 28.5 GHz whereas the second communications band includes a IEEE 802.11ad communications band from 57 GHz to 71 GHz. These examples are merely illustrative. 
     In some scenarios, a first antenna for covering the first communications band is formed at a first location and a second antenna for covering the second communications band is formed at a second location in the electronic device (e.g., first and second locations on opposing sides of the device). While a relatively large separation between the two antennas may enhance isolation between the antennas, forming the antennas at separate locations may occupy an excessive amount of the limited space within device  10 . In order to reduce the amount of space required within device  10  for covering both the first and second frequency bands, the first antenna may be co-located with the second antenna in device  10 . First and second antennas  40  may be considered to be co-located within device  10  when at least some of the antenna resonating element  104  of the first antenna overlaps the outline or footprint of the antenna resonating element  104  in the second antenna. Co-locating the antennas in this way may optimize the amount of space required by the antennas in device  10  for covering both the first and second communications bands. 
       FIG. 7  is a cross-sectional side view showing how a first antenna for covering the first communications band between 10 GHz and 300 GHz may be co-located with a second antenna for covering the second communications band between 10 GHz and 300 GHz. As shown in  FIG. 7 , antenna structures  70  may include a first antenna  40  such as antenna  40 A and a second antenna  40  such as antenna  40 B. Antenna  40 A may cover the first communications band whereas antenna  40 B covers the second communications band. Antenna structures  70  may collectively cover both the first and second communications bands. The second communications band covered by antenna  40 B may include higher frequencies (e.g., frequencies between 57 GHz and 71 GHz) than the first communications band covered by antenna  40 A (e.g., frequencies between 27.5 GHz and 28.5 GHz), for example. 
     In the example of  FIG. 7 , antenna  40 A is a patch antenna such as the single-polarization patch antenna shown in  FIG. 5  or the dual-polarization patch antenna shown in  FIG. 6 . Similarly, antenna  40 B is a patch antenna such as the single-polarization patch antenna shown in  FIG. 5  or the dual-polarization patch antenna shown in  FIG. 6 . This is merely illustrative and, if desired, antennas  40 A and  40 B may be formed using other antenna structures. Antenna structures  70  may sometimes be referred to herein as antenna system  70 , multi-band antenna system  70 , dual-band antenna system  70 , multi-band antenna structures  70 , patch antenna structures  70 , multi-band patch antenna structures  70 , co-located patch antenna structures  70 , or co-located antenna structures  70 . Antennas  40 A and  40 B may sometimes be referred to collectively herein as co-located antennas or co-located patch antennas  40 A and  40 B. 
     As shown in  FIG. 7 , patch antenna  40 A may include patch antenna resonating element  104 A, ground plane  92 , and an antenna feed that includes a positive antenna feed terminal  96 A coupled to patch antenna resonating element  104 A and a corresponding ground antenna feed terminal coupled to ground plane  92 . Patch antenna  40 B may include patch antenna resonating element  104 B, ground plane  92 , and an antenna feed that includes a positive antenna feed terminal  96 B coupled to patch antenna resonating element  104 B and a corresponding ground antenna feed terminal coupled to ground plane  92 . 
     Patch element  104 A may have a lateral surface extending in the X-Y plane of  FIG. 7  and may be separated from antenna ground plane  92  by distance H (e.g., the lateral surface of patch  104 A may extend parallel to the lateral surface of ground plane  92 ). Patch element  104 B may have a lateral surface extending in the X-Y plane and may be separated from patch element  104 A by distance H′ (e.g., the lateral surface of patch  104 B may extend parallel to the lateral surface of ground plane  92  and patch  104 A). Distance H′ may be the same as distance H, less than distance H, or greater than distance H (e.g., patch  104 B may be separated from ground plane  92  by distance H+H′). Patch element  104 B may, for example, serve to reflect some of the antenna signals radiated by patch  104 A if desired. Distances H and H′ may be between 0.1 mm and 10 mm, as examples. In general, adjusting distances H and H′ may serve to adjust the bandwidth of antennas  40 A and  40 B, respectively. 
     Antennas  40 A and  40 B may be formed on a dielectric substrate such as substrate  120 . Substrate  120  may be, for example, a rigid or printed circuit board or other dielectric substrate. Substrate  120  may include multiple dielectric layers  122  (e.g., multiple layers of printed circuit board substrate such as multiple layers of fiberglass-filled epoxy) such as a first dielectric layer  122 - 1 , a second dielectric layer  122 - 2  over the first dielectric layer, a third dielectric layer  122 - 3  over the second dielectric layer, a fourth dielectric layer  122 - 4  over the third dielectric layer, and a fifth dielectric layer  122 - 5  over the fourth dielectric layer. Additional dielectric layers  122  may be stacked within substrate  120  if desired. 
     With this type of arrangement, antenna  40 A may be embedded within the layers of substrate  120 . For example, ground plane  92  may be formed on a surface of second layer  122 - 2  whereas patch antenna resonating element  104 A is formed on a surface of third layer  122 - 3 . Antenna  40 A may be fed using a first transmission line such as transmission line  64 A. Transmission line  64 A may, for example, be formed from a conductive trace such as conductive trace  126 A on layer  122 - 1  and portions of ground layer  92 . Conductive trace  126 A may form the positive signal conductor for transmission line  64 A, for example. A first hole  128 A may be formed in ground layer  92 . First transmission line  64 A may include a vertical conductor  124 A (e.g., a conductive through-via, metal pillar, metal wire, conductive pin, or other vertical conductive interconnect structures) that extends from trace  126 A through layer  122 - 2 , hole  128 A in ground layer  92 , and layer  122 - 3  to antenna feed terminal  96 A on patch element  104 A. This example is merely illustrative and, if desired, other transmission line structures may be used (e.g., coaxial cable structures, stripline transmission line structures, etc.). 
     Patch antenna  40 B may be embedded within the layers of substrate  120 . For example, patch antenna resonating element  104 B may be formed on a surface of dielectric layer  122 - 4 . Some or all of the lateral area of patch antenna resonating element  104 B may overlap with the outline (footprint) of patch antenna resonating element  104 A (in the X-Y plane). Antenna  40 B may be fed using a second transmission line such as transmission line  64 B. Transmission line  64 B may, for example, be formed from a conductive trace such as conductive trace  126 B on layer  122 - 1  and portions of ground layer  92 . Conductive trace  126 B may form the positive signal conductor for transmission line  64 B, for example. A second hole  128 B may be formed in ground layer  92 . A hole  130  may be formed in patch antenna resonating element  104 A. Second transmission line  64 B may include a vertical conductor  124 B (e.g., a conductive through-via, metal pillar, metal wire, conductive pin, or other vertical conductive interconnect structures) that extends from trace  126 B through layer  122 - 2 , hole  128 B in ground layer  92 , layer  122 - 3 , opening  130  in patch element  104 A, and layer  122 - 4  to antenna feed terminal  96 B on patch element  104 B. This example is merely illustrative and, if desired, other transmission line structures may be used (e.g., coaxial cable structures, stripline transmission line structures, etc.). Transmission line traces  126 A and  126 B may be formed on different layers  122  if desired. Vertical conductors  124 A and  124 B may extend through the same hole in ground plane  92  if desired. Holes  128 A and  128 B may sometimes be referred to herein as notches, gaps, openings, or slots. 
     In practice, patch element  104 B alone may have insufficient bandwidth for covering an entirety of the second communications band (e.g., an entirety of the frequency range from 57 GHz to 71 GHz). If desired, antenna  40 B may include one or more parasitic antenna resonating elements that serve to broaden the bandwidth of antenna  40 B. 
     As shown in  FIG. 7 , antenna  40 B may include a parasitic antenna resonating element such as parasitic antenna resonating element  106 . Parasitic antenna resonating element  106  may be formed on a surface of dielectric layer  122 - 5 . Parasitic antenna resonating element  106  may have a lateral surface area extending in the X-Y plane of  FIG. 7  and may be separated from patch element  104 B by distance H″. Distance H″ may be the same as distance H, less than distance H, or greater than distance H (e.g., parasitic  106  may be separated from ground plane  92  by distance H+H′+H″ and may be separated from patch  104 B by distance H′+H″). Distance H″ may be between 0.1 mm and 10 mm, as an example. In general, adjusting distance H″ may serve to adjust the bandwidth of antenna  40 B, for example. Some or all of the lateral area of patch antenna resonating element  106  may overlap with the outline (footprint) of patch antenna resonating element  104 B (in the X-Y plane). 
     Parasitic antenna resonating element  106  may be formed from conductive traces patterned onto a surface of layer  122 - 4 , from stamped sheet metal, metal foil, electronic device housing structures, or any other desired conductive structures. Parasitic antenna resonating element  106  may sometimes be referred to herein as parasitic resonating element  106 , parasitic antenna element  106 , parasitic element  106 , parasitic patch  106 , parasitic conductor  106 , parasitic structure  106 , patch  106 , or parasitic  106 . Parasitic element  106  is not directly fed (e.g., element  106  is not electrically connected to any transmission lines  64 ), whereas patch antenna resonating element  104 B is directly fed via transmission line  64 B and feed terminal  96 B and patch antenna resonating element  104 A is directly fed via transmission line  64 A and feed terminal  96 A. Parasitic element  106  may create a constructive perturbation of the electromagnetic field generated by patch antenna resonating element  104 B, creating a new resonance for antenna  40 B. This may serve to broaden the overall bandwidth of antenna  40 B (e.g., to cover the entire frequency band from 57 GHz to 71 GHz). 
     As shown in  FIG. 7 , patch element  104 A may have a width W. As examples, patch element  104 A may be a rectangular patch (e.g., as shown in  FIGS. 5 and 6 ) having a side of length W, a square patch having four sides of length W, a circular patch having diameter W, an elliptical patch having a major axis length W, or may have any other desired shape (e.g., where width W is the maximum lateral dimension of the patch, the length of a side of a polygonal patch, the length of the longest side of a polygonal patch, the length of a side of a rectangular footprint of the patch, etc.). Patch element  104 B may have a width V. As examples, patch element  104 B may be a rectangular patch (e.g., as shown in  FIGS. 5 and 6 ) having a side of length V, a square patch having four sides of length V, a circular patch having diameter V, an elliptical patch having a major axis length V, or may have any other desired shape (e.g., where width V is the maximum lateral dimension of the patch, the length of a side of a polygonal patch, the length of the longest side of a polygonal patch, the length of a side of a rectangular footprint of the patch, etc.). Width V may be inversely proportional to the frequency of operation of antenna  40 B whereas width W is inversely proportional to the frequency of operation of antenna  40 A. 
     Because antenna  40 B is used to cover higher frequencies than antenna  40 A in the example of  FIG. 7 , width W may be greater than width V. As an example, width W may be approximately equal to twice width V (e.g., width W may be between 1.7 and 2.3 times width V, between 1.8 and 2.2 times width V, twice width V, etc.). Width W of patch  104 A may be approximately equal to half of the wavelength of operation of antenna  40 A. Width V of patch  104 B may be approximately equal to half of the wavelength of operation of antenna  40 B. In practice, widths W and V may depend upon the dielectric constant of dielectric substrate  120  (e.g., widths W and V may be inversely proportional to the dielectric constant of substrate  120 ). As an example, when antenna  40 A is configured to cover a first communications band from 27.5 GHz to 28.5 GHz and antenna  40 B is configured to cover a second communications band from 57 GHz to 71 GHz, width W may be approximately equal to 1.1-2.5 mm for covering the first communications band whereas width V is approximately equal to 0.5-1.25 mm for covering the second communications band. 
     Parasitic element  106  may have a width U. As examples, parasitic element  106  may be a rectangular patch having a side of length U, a square patch having sides of length U, a circular patch having diameter U, an elliptical patch having a major axis length U, a cross-shape having a maximum lateral dimension or a rectangular footprint with a side of length U, or may have any other desired shape (e.g., where width U is the maximum lateral dimension of the patch, the length of a side of a polygonal patch, the length of the longest side of a polygonal patch, the length of a side of a rectangular footprint of the patch, etc.). Width U may be less than, greater than, or equal to width V. In one suitable arrangement, width U is less than or equal to width V (e.g., between 0.05 mm and 1.25 mm). 
     The example of  FIG. 7  is merely illustrative. If desired, additional layers  122  may be interposed between traces  126 A and  126 B and ground layer  92 , between ground layer  92  and patch  104 A, between patch  104 A and patch  104 B, and/or between patch  104 B and parasitic  106 . In another suitable arrangement, substrate  120  may be formed from a single dielectric layer (e.g., antennas  40 A and  40 B may be embedded within a single dielectric layer such as a molded plastic layer). In yet another suitable arrangement, substrate  120  may be omitted and antennas  40 A and  40 B may be formed on other substrate structures or may be formed without substrates. 
     In the example of  FIG. 7 , antennas  40 A and  40 B are shown as having only a single feed for the sake of simplicity. In order to enhance the polarizations covered by antenna structures  70 , antennas  40 A and/or  40 B may be dual-polarized patch antennas that each have two corresponding feeds (e.g., as shown in  FIG. 6 , such that structures  70  have a combined total of four antenna feeds), suitable geometry, and suitable phasing of ports P 1  and P 2 . 
       FIG. 8  is a top-down view showing how antenna structures  70  may include patch antennas  40 A and  40 B that each have two feeds (e.g., for covering multiple or non-linear polarizations). In the example of  FIG. 8 , dielectric  122  is not shown for the sake of clarity. As shown in  FIG. 8 , antenna  40 A may have a first feed at antenna port P 1  that is coupled to a first transmission line  64 A-P 1  and a second feed at antenna port P 2  that is coupled to a second transmission line  64 A-P 2 . The first feed may include a first ground feed terminal coupled to ground plane  92  and a first positive feed terminal  96 A-P 1  coupled to patch antenna resonating element  104 A at a first location on patch antenna resonating element  104 A. The second antenna feed may include a second ground feed terminal coupled to ground plane  92  and a second positive feed terminal  96 A-P 2  coupled to patch antenna resonating element  104 A at a second location on patch antenna resonating element  104 A. For example, the location of first feed terminal  96 A-P 1  may be adjacent to a first side  155  of patch  104 A (e.g., approximately halfway across width W of patch  104 A) whereas the location of second feed terminal  96 A-P 2  is adjacent to a second side  157  of patch  104 A (e.g., approximately halfway across the length of side  157 ). 
     Antenna  40 B may have a third feed at antenna port P 1  that is coupled to a third transmission line  64 B-P 1  and a fourth feed at antenna port P 2  that is coupled to a fourth transmission line  64 B-P 2 . The third feed may include a third ground feed terminal coupled to ground plane  92  and a third positive feed terminal  96 B-P 1  coupled to patch antenna resonating element  104 B at a first location on patch antenna resonating element  104 B (e.g., adjacent to side  153  of patch  104 B approximately halfway across the width V of patch  104 B). The fourth antenna feed may include a fourth ground feed terminal coupled to ground plane  92  and a fourth positive feed terminal  96 B-P 2  coupled to patch antenna resonating element  104 B at a second location on patch antenna resonating element  104 B (e.g., adjacent to side  159  of patch  104 B approximately halfway across side  159 ). 
     Parasitic resonating element  106  may be formed over patch  104 B. At least some or an entirety of parasitic resonating element  106  may overlap patch  104 B. In the example of  FIG. 8 , parasitic resonating element  106  has a cross or “X” shape. In order to form the cross shape, parasitic element  106  may include notches or slots such as slots  143  (e.g., slots formed by removing conductive material from the corners of a square or rectangular metal patch). Cross-shaped parasitic  106  may have a rectangular (e.g., square) footprint. The width U of cross-shaped parasitic element  106  may be defined by the length of a side of the rectangular footprint of element  106 , for example. 
     Cross-shaped parasitic resonating element  106  may include a first arm  140 , a second arm  142 , a third arm  144 , and a fourth arm  146  that extend from the center point  145  of element  106 . First arm  140  may oppose third arm  144  whereas second arm  142  opposes fourth arm  146  (e.g., arms  140  and  144  may extend in parallel and from opposing sides of center point  145  of element  106  and arms  142  and  146  may extend in parallel and from opposing sides of center point  145 ). Arms  142  and  146  may extend along a first longitudinal axis  160  whereas arms  140  and  144  extend along a second longitudinal axis  162 . Longitudinal axis  160  may be oriented at a non-parallel angle with respect to longitudinal axis  162  (e.g., an angle between 0 degrees and 180 degrees). As an example, axis  160  may be oriented at approximately 90 degrees with respect to axis  162 . In the example of  FIG. 8 , the combined length of arms  140  and  144  is equal to the combined length of arms  142  and  146  (e.g., each of arms  140 ,  142 ,  144 , and  146  has the same length). 
     In a single-polarization patch antenna, the distance between the positive antenna feed terminal  96  and the edge of patch  104  may be adjusted to ensure that there is a satisfactory impedance match between patch  104  and the corresponding transmission line  64 . However, such impedance adjustments may not be possible when the antenna is a dual-polarized patch antenna having two feeds. Removing conductive material from parasitic resonating element  106  to form notches  143  may serve to adjust the impedance of patch  104 B so that the impedance of patch  104 B is matched to both transmission lines  64 B-P 1  and  64 B-P 2 , for example. Notches  143  may therefore sometimes be referred to herein as impedance matching notches, impedance matching slots, or impedance matching structures. 
     The dimensions of impedance matching notches  143  may be adjusted (e.g., during manufacture of device  10 ) to ensure that antenna  40 B is sufficiently matched to both transmission lines  64 B-P 1  and  64 B-P 2  and to tweak the overall bandwidth of antenna  40 B. As an example, notches  143  may have sides with lengths U′ that are equal to between 1% and 45% of dimension U of parasitic  106 . In an example where width U is between 1.0 mm and 1.2 mm, length U′ may be between 0.3 mm and 0.4 mm, for example. In order for antenna  40 B to be sufficiently matched to transmission lines  64 B-P 1  and  64 B-P 2 , feed terminals  96 B-P 1  and  96 B-P 2  need to overlap with the conductive material of parasitic element  106 . Notches  143  may therefore be sufficiently small so as not to uncover feed terminals  96 B-P 1  or  96 B-P 2 . In other words, each of antenna feed terminals  96 B-P 1  and  96 B-P 2  may overlap with a respective arm of the cross-shaped parasitic antenna resonating element  106 . During wireless communications using device  10 , device  10  may use ports P 1  and P 2  to transmit and/or receive wireless wave signals with two orthogonal linear polarizations or with a circular or elliptical polarization. The example of  FIG. 8  is merely illustrative. If desired, parasitic antenna resonating element  106  may have additional notches  143 , fewer notches  143 , may have curved edges, straight edges, combinations of straight and curved edges, or any other desired shape. 
     Because arms  144  and  146  need to overlap feed terminals  96 B-P 1  and  96 B-P 2  on patch  104 B, parasitic  106  may be oriented to align with patch  104 B such that the ends of parasitic arms  142  and  146  are parallel to edge  159  of patch  104 B and the ends of parasitic arms  140  and  144  are approximately parallel to edge  153  of patch  104 B (e.g., longitudinal axis  162  of parasitic  106  may be oriented between at an angle between 0 and 10 degrees with respect to edge  159  of patch  104 B whereas longitudinal axis  160  of parasitic  106  may be oriented at an angle between 0 and 10 degrees with respect to edge  153  of patch  104 B). In the example of  FIG. 8 , longitudinal axis  160  of parasitic  106  and edge  153  of patch  104 B are parallel to edge  155  of patch  104 A and longitudinal axis  162  of parasitic  106  and edge  159  of patch  104 B are parallel to edge  157  of patch  104 A. However, this is merely illustrative. If desired, parasitic  106  and patch  104 B may be rotated with respect to patch  104 A (e.g., so long as the arms of parasitic  106  remain parallel to two sides of patch  104 B so that the polarizations associated with ports P 1  and P 2  do not mix). For example, longitudinal axis  160  and side  153  may be rotated at any desired angle between 0 degrees and 360 degrees with respect to edge  155  of patch  104 A. Similarly, longitudinal axis  162  and side  159  may be rotated at any desired angle between 0 degrees and 360 degrees with respect to edge  157  of patch  104 A. In this way, antenna  40 B may have any desired polarization rotated with respect to the polarizations of antenna  40 A. 
     One or more openings  130  may be provided in patch  104 A to accommodate feed terminals  96 B-P 1  and  96 B-P 2  on patch  104 B. In the example of  FIG. 8 , a first opening  130 P 1  is formed in patch  104 A for accommodating feed  96 B-P 1  (e.g., a corresponding vertical conductor  128 B as shown in  FIG. 7  may pass through opening  130 P 1  to feed terminal  96 B-P 1 ) and a second opening  130 P 2  is formed in patch  104 A for accommodating feed  96 B-P 2  (e.g., a corresponding vertical conductor  128 B may pass through opening  130 P 2  to feed terminal  96 B-P 2 ). In another suitable arrangement, a single opening  130  may be formed in patch  104 A for accommodating both feed terminals  96 B-P 1  and  96 B-P 2  (e.g., both vertical conductors  128 B may pass through the same hole  130 ). As one example, a single cross-shaped opening may be formed in patch  104 A. The cross-shaped opening may have first and second opposing arms that have a longitudinal axis that runs between feed terminals  96 A-P 2  and  96 A-P 1  (e.g., oriented at an angle between 0 and 90 degrees such as 45 degrees with respect to axes  160  and  162  in  FIG. 8 ). When configured in this way, the cross-shaped opening may serve to enhance isolation between feed terminals  96 A-P 2  and  96 A-P 1  on patch  104 A. This is merely illustrative and, in general, opening  130  may have any desired shape. 
     In the example of  FIG. 8 , patches  104 A and  104 B are both square patches oriented in the same direction and centered on the same point. This is merely illustrative and, in other scenarios, patches  104 A and  104 B may have other shapes or orientations. Parasitic element  106  may include fewer or more than four arms if desired. In general, parasitic  106  may be referred to herein as a cross-shaped parasitic element in any scenario where parasitic  106  includes at least three arms extending from different sides of a common point on parasitic  106 , where the arms of parasitic  106  extend along at least two non-parallel longitudinal axes. Similarly, opening  130  may be referred to herein as a cross-shaped opening in any scenario where opening  130  includes at least three arms extending from different sides of a common point within the opening, where the arms of the opening extend along at least two non-parallel longitudinal axes. 
       FIG. 9  is a perspective view of multi-band antenna structures  70  having a single cross-shaped opening  130  in patch  104 A. In the example of  FIG. 9 , dielectric  122  is not shown for the sake of clarity. As shown in  FIG. 9 , patch element  104 A may be formed at distance H above ground plane  92 . Patch element  104 B may be formed at distance H′ above patch  104 A. Parasitic element  106  may be formed at distance H″ above patch  104 B. 
     A single cross-shaped opening  130  may be formed in patch  104 A. Cross-shaped opening  130  may have a first arm  150 , a second arm  152 , a third arm  154 , and a fourth arm  156  that extend from the center of opening  130  (e.g., from the center of patch  104 A). Arm  154  may be interposed between the location of feed terminal  96 A-P 1  and the location of feed terminal  96 A-P 2  and may serve to isolate terminals  96 A-P 1  and  96 A-P 2 . Opening  130  may, for example, be a closed slot that is completely surrounded by the conductive material in patch  104 A (e.g., the conductive material in patch  104 A may define all of the edges of opening  130 ). First arm  150  may oppose third arm  154  whereas second arm  152  opposes fourth arm  156 . Arms  150  and  154  may both extend along longitudinal axis  163  (e.g., from opposing sides of the center of patch  104 A) whereas arms  152  and  156  extend along longitudinal axis  167 . 
     Patch  104 B and parasitic  106  may be rotated with respect to patch  104 A. In the example of  FIG. 9 , patch  104 B and parasitic  106  have been rotated to align with two of the arms of opening  130  (e.g., so that arm  156  of opening  130  overlaps the location of feed terminal  96 B-P 2  on patch  104 B and arm  144  of parasitic  106  and arm  154  of opening  130  overlaps the location of feed terminal  96 B-P 1  on patch  104 B and arm  146  of parasitic  106 ). This example is merely illustrative. In general, parasitic  106  and patch  104 B may be rotated at any desired angle with respect to patch  104 A. If desired, cross-shaped opening  130  may be rotated (misaligned) with respect to cross-shaped parasitic  106  (e.g., longitudinal axis  163  may be rotated at an angle between 0 degrees and 90 degrees with respect to axis  162  and axis  167  may be rotated at an angle between 0 degrees and 90 degrees with respect to axis  160 ). By rotating parasitic  106  and patch  104 B in this way, opening  130  may serve to isolate feed terminals  96 A-P 1  and  96 A-P 2  while also accommodating vertical conductors  124  for both feed terminals  96 B-P 1  and  96 B-P 2  of patch  104 B. 
     A first hole  128 A-P 1 , a second hole  128 B-P 1 , a third hole  128 A-P 2 , and a fourth hole  128 B-P 2  may be formed in ground plane  92 . Transmission line  64 A-P 1  (e.g., the corresponding vertical conductor  124  as shown in  FIG. 7 ) may extend through hole  128 A-P 1  to feed terminal  96 A-P 1  on patch  104 A. Transmission line  64 B-P 1  (e.g., the corresponding vertical conductor  124 ) may extend through hole  128 B-P 1  in ground plane  92  and through arm  154  of opening  130  to feed terminal  96 B-P 1  on patch  104 B. Feed terminal  96 B-P 1  may be overlapped by (e.g., may be located directly beneath or within the lateral outline of) arm  144  of parasitic element  106 . Transmission line  64 A-P 2  (e.g., the corresponding vertical conductor  124 ) may extend through hole  128 A-P 2  to feed terminal  96 A-P 2  on patch  104 A. Transmission line  64 B-P 2  (e.g., the corresponding vertical conductor  124 ) may extend through hole  128 B-P 2  in ground plane  92  and arm  156  of opening  130  to feed terminal  96 B-P on patch element  104 B. Feed terminal  96 B-P 2  may be overlapped by arm  146  of parasitic element  106 . 
     In this way, cross-shaped opening  130 , which enhances the isolation between feed terminals  96 A-P 2  and  96 A-P 1  may allow both transmission lines  64 B-P 2  and  64 B-P 1  to pass through patch element  104 A (e.g., without shorting to the conductive material in element  104 A), while parasitic antenna resonating element  106  serves to both broaden the bandwidth of antenna  40 B and impedance match patch  104 B to both transmission lines  64 B-P 1  and  64 B-P 2 . By stacking antennas  40 A and  40 B in this way, the amount of space required to cover both communications bands may be reduced relative to scenarios where antennas  40 A and  40 B are formed at separate locations in device  10 . 
     Transmission lines  64 A-P 1 ,  64 A-P 2 ,  64 B-P 1 , and  64 B-P 2  may include conductive traces  126  formed on a single dielectric layer  122  (e.g., layer  122 - 1  of  FIG. 7 ) or may be formed on two or more different dielectric layers. If desired, two or more of transmission lines  64 A-P 1 ,  64 A-P 2 ,  64 B-P 1 , and  64 B-P 2  may pass through the same opening in ground plane  92 . The example of  FIG. 9  is merely illustrative. In general, parasitic element  106 , patch  104 B, patch  104 A, and ground  92  may have any desired shapes, relative placements, and relative orientations. Opening  130  may have any desired shape having curved and/or straight edges. If desired, separate openings  130  may be provided in patch  104 A for accommodating feed terminals  96 B-P 1  and  96 B-P 2  (e.g., openings  130 P 1  and  130 P 2  as shown in  FIG. 8 ). Parasitic  106  and patch  104 B may be rotated at any desired angle with respect to patch  104 A. 
       FIG. 10  is a top-down view showing one example of how antenna structures  70  of  FIGS. 7-9  may be arranged within a phased antenna array. As shown in  FIG. 10 , multiple antenna structures  70  (e.g., first multi-band antenna structures  70 - 1  including a first co-located pair of antennas  40 A and  40 B, second multi-band antenna structures  70 - 2  including a second co-located pair of antennas  40 A and  40 B, etc.) may be arranged in a grid pattern (e.g., a rectangular grid having rows or columns or in any other desired array pattern). First antenna structures  70 - 1  may be located at a distance  172  with respect to second antenna structures  70 - 2 . Distance  172  may be approximately equal to half of the wavelength of operation of the antennas  40 A in structures  70 - 1  and  70 - 2 . As an example, distance  172  may be between 4 mm and 6 mm (e.g., approximately 5 mm). Separating structures  70 - 1  and  70 - 2  in this way may allow for array  170  to perform beam scanning operations without generating grating lobes in the radiation pattern of array  170 . The presence of excessive grating lobes may result in excessive coupling between structures  70 - 1  and  70 - 2  and reduce the overall antenna efficiency of array  170 , for example. 
     One or more parasitic elements  174  may be interposed between each pair of antenna structures  70  in array  170  to enhance isolation (decoupling) between adjacent structures  70  if desired. In the example of  FIG. 10 , first parasitic element  174 A and second parasitic element  174 B are interposed between antenna structures  70 - 1  and antenna structures  70 - 2 . Parasitic element  174 A may be an un-fed, non-radiative conductive patch. Parasitic element  174 A may be, for example, a rectangular conductive patch or a conductive patch having any other desired shape. Parasitic element  174 A may be located closer to structures  70 - 1  than structures  70 - 2  in one suitable arrangement. In general, element  174 A may be formed at any desired location between structures  70 - 1  and  70 - 2 . If desired, parasitic element  174 A may be formed from conductive traces, stamped sheet metal, metal foil, metal electronic device housing structures, or other conductive structures on the same dielectric layer of substrate  120  as patches  104 A (e.g., layer  122 - 3  of  FIG. 7 ), on a different dielectric layer from patches  104 A, or may be formed on other dielectric support structures or without dielectric support structures. When configured in this way, wireless signals conveyed by antenna  40 A in structures  70 - 1  may interact with patch  174 A as if patch  174 A were an additional ground plane structure for the antenna, for example. Parasitic element  174 A may serve to reduce electromagnetic coupling between antenna  40 A in structures  70 - 1  and antenna  40 A in structures  70 - 2 , thereby enhancing the overall antenna efficiency of array  170 . 
     Parasitic element  174 B may be formed over parasitic element  174 A. Parasitic element  174 B may be an un-fed, non-radiative conductive patch such as a square conductive patch or a conductive patch having any other desired shape. Parasitic element  174 B may be located at a first distance  176  from structures  70 - 1  and a second distance  178  from structures  70 - 2 . Distance  176  may, for example, be approximately equal to half of the wavelength of operation of the antennas  40 B in structures  70 - 1  and  70 - 2 . As an example, distance  176  and/or distance  178  may be between 2 mm and 3 mm. In one suitable arrangement, distance  176  is approximately equal to distance  178 . Because parasitic element  174 A is located closer to structures  70 - 1  than structures  70 - 2 , parasitic element  174 B may thereby be located at a first distance  180  from the edge of parasitic  174 A closest to structures  70 - 1  and a second shorter distance  182  from the opposing edge of parasitic  174 A (e.g., parasitic  174 B may be misaligned with respect to the center of parasitic  174 A). 
     If desired, parasitic element  174 B may be formed from conductive traces, stamped sheet metal, metal foil, metal electronic device housing structures, or other conductive structures on the same dielectric layer of substrate  120  as patches  104 B (e.g., layer  122 - 4  of  FIG. 7 ), on a different dielectric layer from patches  104 B, or may be formed on other dielectric support structures or without dielectric support structures. Parasitic element  174 B may serve to reduce electromagnetic coupling between antenna  40 B in structures  70 - 1  and antenna  40 B in structures  70 - 2 , thereby enhancing the overall antenna efficiency of array  170 . 
     The example of  FIG. 10  is merely illustrative. If desired, parasitic elements  174 A and/or  174 B may be shorted to ground plane  92 . In general, any desired parasitic elements having any desired placement, shape, and orientation may be interposed between structures  70 - 1  and  70 - 2 . In the example of  FIG. 10 , the center of structures  70 - 1  (e.g., the center of the corresponding patches  104 A and  104 B and the center of the corresponding parasitic  106 ) is shown as being located at distance  172  from center the center of structures  70 - 2 . Similarly, the center of structures  70 - 1  is shown as being located at distance  176  from the center of parasitic  174 B. This is merely illustrative. In general, any desired point within the outline or on the edges of structures  70 - 1  (e.g., within the outline or on the edges of patch  104 A) may be located at distance  172  from any desired point within the outline or on the edges of structures  70 - 2  and may be located at distance  176  from any desired point within the outline or on the edges of parasitic  174 B. Array  170  may include any desired number of structures  70  (e.g., sixteen structures  70  and therefore thirty two antennas  40 , fourteen structures  70  and therefore twenty-eight antennas  40 , between ten and fourteen structures  70 , between three and ten structures  70 , more than sixteen structures  70 , five structures  70  and therefore ten antennas  40 , six structures  70  and therefore twelve antennas  40 , etc.). In general, a greater number of structures  70  may increase the overall gain of array  170  (but also the overall manufacturing and operating complexity of array  60 ) relative to scenarios where fewer structures  70  are formed. Structures  70  may be arranged in any desired pattern. 
       FIG. 11  is a top-down view showing another example of how antenna structures  70  of  FIGS. 7-9  may be arranged within a phased antenna array  170 . As shown in  FIG. 11 , multiple antenna structures  70  may be arranged in a grid or array (e.g., an array having aligned rows and columns). Each antenna structure  70  may be located at distance  172  with respect to the antenna structures  70  in adjacent rows and columns of the array. Two parasitic elements  174 A may be interposed between each adjacent pair of antenna structures  70 . Additional patch elements  104 B and corresponding cross-shaped antenna resonating elements  106  may be interposed between each pair of antenna structures  70  (e.g., between two corresponding parasitic elements  174 A). The patch element  104 B and corresponding parasitic  106  within each antenna structure  70  may be located at a distance  177  from the patches  104 B and parasitic elements  106  between structures  70 . Distance  177  may be, for example, half of the wavelength of operation of antennas  40 B. When arranged in this way, phased antenna array  170  may include patches  104 B and the corresponding parasitic elements  106  arranged in an array having rows and columns, where patches  104 B are located in every-other row and column. In this way, the patches  104 B between structures  70  may utilize the same ground plane  92  as patches  104 A. The example of  FIG. 11  is merely illustrative. If desired, patches  104 B and  104 A may be arranged in any desired manner. The rows and columns of array  170  need not be aligned. 
       FIG. 12  is a graph in which antenna performance (antenna efficiency) has been plotted as a function of operating frequency F for antenna structures  70 . As shown in  FIG. 12 , efficiency curve  190  illustrates the antenna efficiency of structures  70  when operated in the absence of parasitic element  106 . Curve  190  may have a first peak at within a first communications band BI between frequencies FA and FB and a second peak at frequency F′. Frequency F′ may lie within a second communications BII between frequencies FC and FD. First communications band BI may sometimes be referred to herein as low band BI. Second communications band BII may sometimes be referred to herein as high band BII. The second peak of curve  190  at frequency F′ may have a bandwidth that is too narrow to cover the entirety of communications band BII. Efficiency curve  192  illustrates the antenna efficiency of parasitic element  106 . Curve  192  may have a peak at frequency F′+ΔF that is offset from frequency F′ by offset value ΔF. 
     Efficiency curve  194  illustrates the antenna efficiency of structures  70  including the contributions of antenna  40 A and antenna  40 B having parasitic element  106 . Efficiency curve  194  may exhibit a first peak in first communications band BI between frequencies FA and FB (e.g., due to the contribution of antenna  40 A). Efficiency curve  194  may exhibit a second peak in second communications band BII between frequencies FC and FD due to the contribution of antenna  40 B. As shown in  FIG. 11 , the antenna efficiency of antenna  40 B in band BII may include contributions from both patch  104 B and parasitic  106  such that antenna  40 B exhibits an extended bandwidth that covers the entirety of band BII between frequencies FC and FD. 
     In one suitable example, frequency FA is 27.5 GHz, frequency FB is 28.5 GHz, frequency FC is 57 GHz, and frequency FD 71 GHz. This is merely illustrative and, in general, bands BI and BII may be any desired communications bands at frequencies between 10 GHz and 300 GHz. Frequencies FA through FD may be any desired frequencies between 10 GHz and 300 GHz (e.g., where frequency FA is less than frequency FB, frequency FB is less than frequency FC, and frequency FC is less than frequency FD). In this way, co-located antennas  40 A and  40 B (i.e., multi-band antenna structure  70 ) may cover multiple frequency bands greater than 10 GHz with satisfactory antenna efficiency in both bands and without occupying as much space within device  10  as when antennas  40 A and  40 B are formed at different locations within device  10 , for example. 
     The example of  FIG. 12  is merely illustrative. In general, curve  194  may have any desired shape (e.g., as determined by the arrangement of antennas  40 A and  40 B within structure  70 ). If desired, control circuitry  14  may perform simultaneous communications in bands BI and BII at any given time (e.g., because antenna  40 A is suitably isolated from antenna  40 B). If desired, antennas  40 A or antenna  40 B may be omitted from structure  70  (e.g., for only covering one of the first and second communications bands). 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20170714
Publication Date: 20200512
Grant Date: 20200512
Priority Date: 20170714
Inventors: PAULOTTO, Simone
NOORI, BASIM H.
MOW, MATTHEW A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q5/392", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q19/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/35", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q19/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/045", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/392", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/35", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q19/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/392", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/045", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 64999737