PATENT DOCUMENT

Publication Number: US-11894608-B2
Application Number: US-202217751495-A
Country: US
Kind Code: B2

Title: Electronic devices having multilayer millimeter wave antennas

Abstract:
An electronic device may have a phased antenna array. An antenna in the array may include a rectangular patch element with diagonal axes. The antenna may have first and second antenna feeds coupled to the patch element along the diagonal axes. The antenna may be rotated at a forty-five degree angle relative to other antennas in the array. The antenna may have one or two layers of parasitic elements overlapping the patch element. For example, the antenna may have a layer of coplanar parasitic patches separated by a gap. The antenna may also have an additional parasitic patch that is located farther from the patch element than the layer of coplanar parasitic patches. The additional parasitic patch may overlap the patch element and the gap in the coplanar parasitic patches. The antenna may exhibit a relatively small footprint and minimal mutual coupling with other antennas in the array.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a dielectric substrate; and 
 an antenna array that includes an antenna, the antenna including:
 a rectangular conductive patch on the dielectric substrate, the rectangular conductive patch having first and second opposing corners and a diagonal axis that passes through the first and second opposing corners of the rectangular conductive patch, 
 an antenna feed terminal coupled to the rectangular conductive patch along the diagonal axis, and 
 a parasitic conductor on the dielectric substrate and overlapping the rectangular conductive patch. 
 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the rectangular conductive patch has a first edge, and the parasitic conductor has a first edge that is parallel to the first edge of the rectangular conductive patch. 
     
     
       3. The electronic device defined in  claim 2 , wherein the rectangular conductive patch has a second edge, and the parasitic conductor has a second edge that is parallel to the second edge of the rectangular conductive patch. 
     
     
       4. The electronic device defined in  claim 3 , wherein the first and second edges of the rectangular conductive patch meet at the first corner of the rectangular conductive patch. 
     
     
       5. The electronic device defined in  claim 4 , wherein the parasitic conductor is rectangular and is smaller than the rectangular conductive patch. 
     
     
       6. The electronic device defined in  claim 1  further comprising:
 an additional parasitic conductor on the dielectric substrate and overlapping the rectangular conductive patch. 
 
     
     
       7. The electronic device defined in  claim 6 , wherein the parasitic conductor overlaps a center of the rectangular conductive patch, and the additional parasitic conductor overlaps an edge of the rectangular conductive patch. 
     
     
       8. The electronic device defined in  claim 7 , wherein the parasitic conductor and the additional parasitic conductor are formed on a same layer of the dielectric substrate. 
     
     
       9. The electronic device defined in  claim 7 , wherein the parasitic conductor and the additional parasitic conductor are formed on different layers of the dielectric substrate. 
     
     
       10. The electronic device defined in  claim 9 , wherein the parasitic conductor is capacitively coupled to the additional parasitic conductor, and the additional parasitic conductor is capacitively coupled to the rectangular conductive patch. 
     
     
       11. The electronic device defined in  claim 1 , wherein the antenna array includes an additional antenna including:
 an additional rectangular conductive patch having a diagonal axis that is colinear with the diagonal axis of the rectangular conductive patch. 
 
     
     
       12. The electronic device defined in  claim 11 , wherein the additional rectangular conductive patch has first and second opposing corners and the diagonal axis of the additional rectangular conductive patch passes through the first and second opposing corners of the additional rectangular conductive patch. 
     
     
       13. The electronic device defined in  claim 1 , wherein the antenna feed terminal is a positive antenna feed terminal configured to be coupled to a signal conductor of a radio-frequency transmission line path. 
     
     
       14. An electronic device comprising:
 a dielectric substrate having a first layer and a second layer stacked on the first layer; 
 a conductive patch for an antenna; 
 ground traces on the dielectric substrate forming an antenna ground for the antenna; 
 signal traces forming a signal conductor of a radio-frequency transmission line path; 
 a positive antenna feed terminal coupled to the conductive patch; 
 a conductive via that couples the signal traces to the positive antenna feed terminal; 
 a first parasitic conductor on the first layer and capacitively coupled to the conductive patch; and 
 a second parasitic conductor on the second layer and capacitively coupled to the first parasitic conductor. 
 
     
     
       15. The electronic device defined in  claim 14 , wherein the second parasitic conductor overlaps a center of the conductive patch, and the first parasitic conductor overlaps an edge of the conductive patch. 
     
     
       16. The electronic device defined in  claim 15 , wherein the second parasitic conductor is separated from the conductive patch by a first distance, and the first parasitic conductive is separated from the conductive patch by a second distance less than the first distance. 
     
     
       17. The electronic device defined in  claim 14 , wherein the ground traces have an opening and the conductive via passes through the opening. 
     
     
       18. The electronic device defined in  claim 14 , wherein the dielectric substrate has a third layer on which the first and second layers are stacked, the conductive patch being disposed on the third layer. 
     
     
       19. The electronic device defined in  claim 14 , wherein the conductive patch has a diagonal axis, and the positive antenna feed terminal is coupled to the conductive patch along the diagonal axis. 
     
     
       20. The electronic device defined in  claim 14 , wherein the first and second parasitic conductors are coplanar.

Description:
This application is a continuation of U.S. patent application Ser. No. 17/028,864, filed Sep. 22, 2020, which is hereby incorporated by reference herein in its entirety. 
    
    
     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 signals generated by antennas can be characterized by substantial attenuation and/or distortion during signal propagation through various mediums. In addition, if care is not taken, the antennas can be susceptible to undesirable mutual coupling. 
     It would therefore be desirable to be able to provide electronic devices with improved wireless communications circuitry such as communications circuitry that supports millimeter and centimeter wave communications. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry. The wireless circuitry may include a phased antenna array. The phased antenna array may convey radio-frequency signals in a signal beam at a frequency greater than 10 GHz. 
     An antenna in the phased antenna array may include a rectangular patch element. The rectangular patch element may have first and second diagonal axes. The antenna may have a first positive antenna feed terminal coupled to the rectangular patch element along the first diagonal axis. The antenna may have a second positive antenna feed terminal coupled to the rectangular patch element along the second diagonal axis. The antenna may be rotated at a forty-five degree angle with respect to adjacent antennas in the phased antenna array. 
     The antenna may have parasitic elements overlapping the patch element. For example, the antenna may have five parasitics formed in a single layer overlapping the patch element. Gaps may separate each of the parasitics from each other. As another example, the antenna may have a layer of coplanar parasitic patches overlapping the patch element. The parasitic patches in this layer may be separated by a gap. The antenna may also have an additional parasitic patch that is located farther from the patch element than the layer of coplanar parasitic patches. The additional parasitic patch may overlap the patch element and the gap in the layer of coplanar parasitic patches. When configured in this way, the antenna may exhibit a relatively small footprint and minimal mutual coupling with other antennas in the array. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a front perspective view of an illustrative electronic device with wireless circuitry in accordance with some embodiments. 
         FIG.  2    is a rear perspective view of an illustrative electronic device with wireless circuitry in accordance with some embodiments. 
         FIG.  3    is a schematic diagram of an illustrative electronic device with wireless circuitry in accordance with some embodiments. 
         FIG.  4    is a diagram of an illustrative phased antenna array that forms a radio-frequency signal beam at different beam pointing angles in accordance with some embodiments. 
         FIG.  5    is a diagram of illustrative wireless circuitry in accordance with some embodiments. 
         FIG.  6    is a top view of an illustrative antenna having diagonally-oriented feed terminals in accordance with some embodiments. 
         FIG.  7    is a cross-sectional side view of an illustrative antenna having diagonally-oriented feed terminals in accordance with some embodiments. 
         FIG.  8    is a plot of antenna performance (mutual coupling) as a function of frequency for an illustrative antenna having diagonally-oriented feed terminals in accordance with some embodiments. 
         FIG.  9    is a top view of an illustrative antenna having multi-layer parasitic elements in accordance with some embodiments. 
         FIG.  10    is a cross-sectional side view of an illustrative antenna having multi-layer parasitic elements in accordance with some embodiments. 
         FIG.  11    is a plot of antenna performance (return loss) as a function of frequency for illustrative antennas in accordance with some embodiments. 
     
    
    
     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 performing wireless communications and/or spatial ranging operations using millimeter and centimeter wave signals. Millimeter wave signals, which are sometimes referred to as extremely high frequency (EHF) signals, propagate at frequencies above about 30 GHz (e.g., at 60 GHz or other frequencies between about 30 GHz and 300 GHz). Centimeter wave signals propagate at frequencies between about 10 GHz and 30 GHz. If desired, device  10  may also contain antennas 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 portable speaker, a keyboard, a gaming controller, a gaming system, 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, portable speaker, 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  8 . Display  8  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  8  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 sensor electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  8  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  8  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, sapphire, or other transparent dielectrics. 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 implement beam steering, etc.) may be mounted under an inactive border region of display  8  (see, e.g., illustrative antenna locations  6  of  FIG.  1   ). Display  8  may contain an active area with an array of pixels (e.g., a central rectangular portion). Inactive areas of display  8  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  6  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  8  on the front of device  10 , over a dielectric window on a rear face of housing  12  or the edge of housing  12 , over a dielectric cover layer such as a dielectric rear housing wall that covers some or all of the rear face of device  10 , or elsewhere in device  10 . 
       FIG.  2    is a rear perspective view of electronic device  10  showing illustrative locations  6  on the rear and sides of housing  12  in which antennas (e.g., single antennas and/or phased antenna arrays) may be mounted in device  10 . The antennas may be mounted at the corners of device  10 , along the edges of housing  12  such as edges formed by sidewalls  12 E, on upper and lower portions of rear housing 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 wall  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 (e.g., plastic, glass, sapphire, ceramic, fabric, etc.), the antennas 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 dielectrics. The antennas 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 wireless equipment from the antennas mounted within the interior of device  10  and may allow internal antennas to receive antenna signals from external wireless equipment. In another suitable arrangement, the antennas may be mounted on the exterior of conductive portions of housing  12 . 
       FIGS.  1  and  2    are merely illustrative. In general, housing  12  may have any desired shape (e.g., a rectangular shape, a cylindrical shape, a spherical shape, combinations of these, etc.). Display  8  of  FIG.  1    may be omitted if desired. Antennas may be located within housing  12 , on housing  12 , and/or external to housing  12 . 
     A schematic diagram of illustrative components that may be used in device  10  is shown in  FIG.  3   . As shown in  FIG.  3   , device  10  may include control circuitry  14 . Control circuitry  14  may include storage such as storage circuitry  20 . Storage circuitry  20  may include hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid-state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. 
     Control circuitry  14  may include processing circuitry such as processing circuitry  22 . Processing circuitry  22  may be used to control the operation of device  10 . Processing circuitry  22  may include on one or more microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application specific integrated circuits, central processing units (CPUs), etc. Control circuitry  14  may be configured to perform operations in device  10  using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing operations in device  10  may be stored on storage circuitry  20  (e.g., storage circuitry  20  may include non-transitory (tangible) computer readable storage media that stores the software code). The software code may sometimes be referred to as program instructions, software, data, instructions, or code. Software code stored on storage circuitry  20  may be executed by processing circuitry  22 . 
     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, antenna-based spatial ranging protocols (e.g., radio detection and ranging (RADAR) protocols or other desired range detection protocols for signals conveyed at millimeter and centimeter wave frequencies), etc. Each communication protocol may be associated with a corresponding radio access technology (RAT) that specifies the physical connection methodology used in implementing the protocol. 
     Device  10  may include input-output circuitry  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, sensors, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, gyroscopes, accelerometers or other components that can detect motion and device orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components. 
     Input-output circuitry  16  may include wireless circuitry such as wireless circuitry  24  for wirelessly conveying radio-frequency signals. While control circuitry  14  is shown separately from wireless circuitry  24  in the example of  FIG.  3    for the sake of clarity, wireless circuitry  24  may include processing circuitry that forms a part of processing circuitry  22  and/or storage circuitry that forms a part of storage circuitry  20  of control circuitry  14  (e.g., portions of control circuitry  14  may be implemented on wireless circuitry  24 ). As an example, control circuitry  14  may include baseband processor circuitry or other control components that form a part of wireless circuitry  24 . 
     Wireless circuitry  24  may include millimeter and centimeter wave transceiver circuitry such as millimeter/centimeter wave transceiver circuitry  28 . Millimeter/centimeter wave transceiver circuitry  28  may support communications at frequencies between about 10 GHz and 300 GHz. For example, millimeter/centimeter wave 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, millimeter/centimeter wave 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, millimeter/centimeter wave transceiver 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) New Radio (NR) Frequency Range 2 (FR2) communications bands between about 24 GHz and 90 GHz. Millimeter/centimeter wave transceiver 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.). 
     Millimeter/centimeter wave transceiver circuitry  28  (sometimes referred to herein simply as transceiver circuitry  28  or millimeter/centimeter wave circuitry  28 ) may perform spatial ranging operations using radio-frequency signals at millimeter and/or centimeter wave frequencies that are transmitted and received by millimeter/centimeter wave transceiver circuitry  28 . The received signals may be a version of the transmitted signals that have been reflected off of external objects and back towards device  10 . Control circuitry  14  may process the transmitted and received signals to detect or estimate a range between device  10  and one or more external objects in the surroundings of device  10  (e.g., objects external to device  10  such as the body of a user or other persons, other devices, animals, furniture, walls, or other objects or obstacles in the vicinity of device  10 ). If desired, control circuitry  14  may also process the transmitted and received signals to identify a two or three-dimensional spatial location of the external objects relative to device  10 . 
     Spatial ranging operations performed by millimeter/centimeter wave transceiver circuitry  28  are unidirectional. If desired, millimeter/centimeter wave transceiver circuitry  28  may also perform bidirectional communications with external wireless equipment such as external wireless equipment  10 ′ (e.g., over bi-directional millimeter/centimeter wave wireless communications link  31 ). External wireless equipment  10 ′ may include other electronic devices such as electronic device  10 , a wireless base station, wireless access point, a wireless accessory, or any other desired equipment that transmits and receives millimeter/centimeter wave signals. Bidirectional communications involve both the transmission of wireless data by millimeter/centimeter wave transceiver circuitry  28  and the reception of wireless data that has been transmitted by external wireless equipment  10 ′. The wireless data may, for example, include data that has been encoded into corresponding data packets such as wireless data associated with a telephone call, streaming media content, internet browsing, wireless data associated with software applications running on device  10 , email messages, etc. 
     If desired, wireless circuitry  24  may include transceiver circuitry for handling communications at frequencies below 10 GHz such as non-millimeter/centimeter wave transceiver circuitry  26 . For example, non-millimeter/centimeter wave transceiver circuitry  26  may handle wireless local area network (WLAN) communications bands such as the 2.4 GHz and 5 GHz Wi-Fi® (IEEE 802.11) bands, wireless personal area network (WPAN) communications bands such as the 2.4 GHz Bluetooth® communications band, cellular telephone communications bands such as a cellular low band (LB) (e.g., 600 to 960 MHz), a cellular low-midband (LMB) (e.g., 1400 to 1550 MHz), a cellular midband (MB) (e.g., from 1700 to 2200 MHz), a cellular high band (HB) (e.g., from 2300 to 2700 MHz), a cellular ultra-high band (UHB) (e.g., from 3300 to 5000 MHz, or other cellular communications bands between about 600 MHz and about 5000 MHz (e.g., 3G bands, 4G LTE bands, 5G New Radio Frequency Range 1 (FR1) bands below 10 GHz, etc.), a near-field communications (NFC) band (e.g., at 13.56 MHz), satellite navigations bands (e.g., an L1 global positioning system (GPS) band at 1575 MHz, an L5 GPS band at 1176 MHz, a Global Navigation Satellite System (GLONASS) band, a BeiDou Navigation Satellite System (BDS) band, etc.), ultra-wideband (UWB) communications band(s) supported by the IEEE 802.15.4 protocol and/or other UWB communications protocols (e.g., a first UWB communications band at 6.5 GHz and/or a second UWB communications band at 8.0 GHz), and/or any other desired communications bands. The communications bands handled by the radio-frequency transceiver circuitry may sometimes be referred to herein as frequency bands or simply as “bands,” and may span corresponding ranges of frequencies. Non-millimeter/centimeter wave transceiver circuitry  26  and millimeter/centimeter wave transceiver circuitry  28  may each include one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive radio-frequency components, switching circuitry, transmission line structures, and other circuitry for handling radio-frequency signals. 
     In general, the transceiver circuitry in wireless circuitry  24  may cover (handle) any desired frequency bands of interest. As shown in  FIG.  3   , wireless circuitry  24  may include antennas  30 . The transceiver circuitry may convey radio-frequency signals using one or more antennas  30  (e.g., antennas  30  may convey the radio-frequency signals for the transceiver circuitry). The term “convey radio-frequency signals” as used herein means the transmission and/or reception of the radio-frequency signals (e.g., for performing unidirectional and/or bidirectional wireless communications with external wireless communications equipment). Antennas  30  may transmit the radio-frequency signals by radiating the radio-frequency signals into free space (or to freespace through intervening device structures such as a dielectric cover layer). Antennas  30  may additionally or alternatively receive the radio-frequency signals from free space (e.g., through intervening devices structures such as a dielectric cover layer). The transmission and reception of radio-frequency signals by antennas  30  each involve the excitation or resonance of antenna currents on an antenna resonating element in the antenna by the radio-frequency signals within the frequency band(s) of operation of the antenna. 
     In satellite navigation system links, cellular telephone links, and other long-range links, radio-frequency signals are typically used to convey data over thousands of feet or miles. In Wi-Fi® and Bluetooth® links at 2.4 and 5 GHz and other short-range wireless links, radio-frequency signals are typically used to convey data over tens or hundreds of feet. Millimeter/centimeter wave transceiver circuitry  28  may convey radio-frequency signals over short distances that travel over a line-of-sight path. To enhance signal reception for millimeter and centimeter wave communications, phased antenna arrays and beam forming (steering) techniques may be used (e.g., schemes in which antenna signal phase and/or magnitude for each antenna in an array are 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. 
     Antennas  30  in wireless circuitry  24  may be formed using any suitable antenna types. For example, antennas  30  may include antennas with resonating elements that are formed from stacked patch antenna structures, loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, monopole antenna structures, dipole antenna structures, helical antenna structures, Yagi (Yagi-Uda) antenna structures, hybrids of these designs, etc. If desired, one or more of antennas  30  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 non-millimeter/centimeter wave wireless link for non-millimeter/centimeter wave transceiver circuitry  26  and another type of antenna may be used in conveying radio-frequency signals at millimeter and/or centimeter wave frequencies for millimeter/centimeter wave transceiver circuitry  28 . Antennas  30  that are used to convey radio-frequency signals at millimeter and centimeter wave frequencies may be arranged in one or more phased antenna arrays. In one suitable arrangement that is described herein as an example, the antennas  30  that are arranged in a corresponding phased antenna array may be stacked patch antennas having patch antenna resonating elements that overlap and are vertically stacked with respect to one or more parasitic patch elements. 
       FIG.  4    is a diagram showing how antennas  30  for handling radio-frequency signals at millimeter and centimeter wave frequencies may be formed in a phased antenna array. As shown in  FIG.  4   , phased antenna array  36  (sometimes referred to herein as array  36 , antenna array  36 , or array  36  of antennas  30 ) may be coupled to radio-frequency transmission line paths  32 . For example, a first antenna  30 - 1  in phased antenna array  36  may be coupled to a first radio-frequency transmission line path  32 - 1 , a second antenna  30 - 2  in phased antenna array  36  may be coupled to a second radio-frequency transmission line path  32 - 2 , an Mth antenna  30 -M in phased antenna array  36  may be coupled to an Mth radio-frequency transmission line path  32 -M, etc. While antennas  30  are described herein as forming a phased antenna array, the antennas  30  in phased antenna array  36  may sometimes also be referred to as collectively forming a single phased array antenna (e.g., where each antenna  30  in the phased array antenna forms an antenna element of the phased array antenna). 
     Radio-frequency transmission line paths  32  may each be coupled to millimeter/centimeter wave transceiver circuitry  28  of  FIG.  3   . Each radio-frequency transmission line path  32  may include one or more radio-frequency transmission lines, a positive signal conductor, and a ground signal conductor. The positive signal conductor may be coupled to a positive antenna feed terminal on an antenna resonating element of the corresponding antenna  30 . The ground signal conductor may be coupled to a ground antenna feed terminal on an antenna ground for the corresponding antenna  30 . 
     Radio-frequency transmission line paths  32  may include stripline transmission lines (sometimes referred to herein simply as striplines), coaxial cables, coaxial probes realized by metalized vias, microstrip transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, conductive vias, combinations of these, etc. Multiple types of transmission lines may be used to couple the millimeter/centimeter wave transceiver circuitry to phased antenna array  36 . Filter circuitry, switching circuitry, impedance matching circuitry, phase shifter circuitry, amplifier circuitry, and/or other circuitry may be interposed on radio-frequency transmission line path  32 , if desired. 
     Radio-frequency transmission lines in device  10  may be integrated into ceramic substrates, rigid printed circuit boards, and/or flexible printed circuits. In one suitable arrangement, radio-frequency transmission lines in device  10  may be integrated within multilayer laminated structures (e.g., layers of a conductive material such as copper and a dielectric material such as a resin that are laminated together without intervening adhesive) that may be folded or bent in multiple dimensions (e.g., two or three dimensions) and that maintain a bent or folded shape after bending (e.g., the multilayer laminated structures may be folded into a particular three-dimensional shape to route around other device components and may be rigid enough to hold its shape after folding without being held in place by stiffeners or other structures). All of the multiple layers of the laminated structures may be batch laminated together (e.g., in a single pressing process) without adhesive (e.g., as opposed to performing multiple pressing processes to laminate multiple layers together with adhesive). 
     Antennas  30  in phased antenna array  36  may be arranged in any desired number of rows and columns or in any other desired pattern (e.g., the antennas need not be arranged in a grid pattern having rows and columns). During signal transmission operations, radio-frequency transmission line paths  32  may be used to supply signals (e.g., radio-frequency signals such as millimeter wave and/or centimeter wave signals) from millimeter/centimeter wave transceiver circuitry  28  ( FIG.  3   ) to phased antenna array  36  for wireless transmission. During signal reception operations, radio-frequency transmission line paths  32  may be used to convey signals received at phased antenna array  36  (e.g., from external wireless equipment  10 ′ of  FIG.  3   ) to millimeter/centimeter wave transceiver circuitry  28  ( FIG.  3   ). 
     The use of multiple antennas  30  in phased antenna array  36  allows radio-frequency beam forming arrangements (sometimes referred to herein as radio-frequency beam steering arrangements) to be implemented by controlling the relative phases and magnitudes (amplitudes) of the radio-frequency signals conveyed by the antennas. In the example of  FIG.  4   , the antennas  30  in phased antenna array  36  each have a corresponding radio-frequency phase and magnitude controller  33  (e.g., a first phase and magnitude controller  33 - 1  interposed on radio-frequency transmission line path  32 - 1  may control phase and magnitude for radio-frequency signals handled by antenna  30 - 1 , a second phase and magnitude controller  33 - 2  interposed on radio-frequency transmission line path  32 - 2  may control phase and magnitude for radio-frequency signals handled by antenna  30 - 2 , an Mth phase and magnitude controller  33 -M interposed on radio-frequency transmission line path  32 -M may control phase and magnitude for radio-frequency signals handled by antenna  30 -M, etc.). 
     Phase and magnitude controllers  33  may each include circuitry for adjusting the phase of the radio-frequency signals on radio-frequency transmission line paths  32  (e.g., phase shifter circuits) and/or circuitry for adjusting the magnitude of the radio-frequency signals on radio-frequency transmission line paths  32  (e.g., power amplifier and/or low noise amplifier circuits). Phase and magnitude controllers  33  may sometimes be referred to collectively herein as beam steering or beam forming circuitry (e.g., beam steering circuitry that steers the beam of radio-frequency signals transmitted and/or received by phased antenna array  36 ). 
     Phase and magnitude controllers  33  may adjust the relative phases and/or magnitudes of the transmitted signals that are provided to each of the antennas in phased antenna array  36  and may adjust the relative phases and/or magnitudes of the received signals that are received by phased antenna array  36 . Phase and magnitude controllers  33  may, if desired, include phase detection circuitry for detecting the phases of the received signals that are received by phased antenna array  36 . The term “beam,” “signal beam,” “radio-frequency beam,” or “radio-frequency signal beam” may be used herein to collectively refer to wireless signals that are transmitted and received by phased antenna array  36  in a particular direction. The signal beam may exhibit a peak gain that is oriented in a particular beam pointing direction at a corresponding beam pointing angle (e.g., based on constructive and destructive interference from the combination of signals from each antenna in the phased antenna array). The term “transmit beam” may sometimes be used herein to refer to radio-frequency signals that are transmitted in a particular direction whereas the term “receive beam” may sometimes be used herein to refer to radio-frequency signals that are received from a particular direction. 
     If, for example, phase and magnitude controllers  33  are adjusted to produce a first set of phases and/or magnitudes for transmitted radio-frequency signals, the transmitted signals will form a transmit beam as shown by beam B 1  of  FIG.  4    that is oriented in the direction of point A. If, however, phase and magnitude controllers  33  are adjusted to produce a second set of phases and/or magnitudes for the transmitted signals, the transmitted signals will form a transmit beam as shown by beam B 2  that is oriented in the direction of point B. Similarly, if phase and magnitude controllers  33  are adjusted to produce the first set of phases and/or magnitudes, radio-frequency signals (e.g., radio-frequency signals in a receive beam) may be received from the direction of point A, as shown by beam B 1 . If phase and magnitude controllers  33  are adjusted to produce the second set of phases and/or magnitudes, radio-frequency signals may be received from the direction of point B, as shown by beam B 2 . 
     Each phase and magnitude controller  33  may be controlled to produce a desired phase and/or magnitude based on a corresponding control signal S received from control circuitry  38  of  FIG.  4    over control paths  34  (e.g., the phase and/or magnitude provided by phase and magnitude controller  33 - 1  may be controlled using control signal S 1  on control path  34 - 1 , the phase and/or magnitude provided by phase and magnitude controller  33 - 2  may be controlled using control signal S 2  on control path  34 - 2 , the phase and/or magnitude provided by phase and magnitude controller  33 -M may be controlled using control signal SM on control path  34 -M, etc.). If desired, control circuitry  38  may actively adjust control signals S in real time to steer the transmit or receive beam in different desired directions (e.g., to different desired beam pointing angles) over time. Phase and magnitude controllers  33  may provide information identifying the phase of received signals to control circuitry  38  if desired. 
     When performing wireless communications using radio-frequency signals at millimeter and centimeter wave frequencies, the radio-frequency signals are conveyed over a line of sight path between phased antenna array  36  and external wireless equipment (e.g., external wireless equipment  10 ′ of  FIG.  3   ). If the external wireless equipment is located at point A of  FIG.  4   , phase and magnitude controllers  33  may be adjusted to steer the signal beam towards point A (e.g., to form a signal beam having a beam pointing angle directed towards point A). Phased antenna array  36  may then transmit and receive radio-frequency signals in the direction of point A. Similarly, if the external wireless equipment is located at point B, phase and magnitude controllers  33  may be adjusted to steer the signal beam towards point B (e.g., to form a signal beam having a beam pointing angle directed towards point B). Phased antenna array  36  may then transmit and receive radio-frequency signals in the direction of point B. In the example of  FIG.  4   , beam steering is shown as being performed over a single degree of freedom for the sake of simplicity (e.g., towards the left and right on the page of  FIG.  4   ). However, in practice, the beam may be steered over two or more degrees of freedom (e.g., in three dimensions, into and out of the page and to the left and right on the page of  FIG.  4   ). Phased antenna array  36  may have a corresponding field of view over which beam steering can be performed (e.g., in a hemisphere or a segment of a hemisphere over the phased antenna array). If desired, device  10  may include multiple phased antenna arrays that each face a different direction to provide coverage from multiple sides of the device. 
     Control circuitry  38  of  FIG.  4    may form a part of control circuitry  14  of  FIG.  3    or may be separate from control circuitry  14  of  FIG.  3   . Control circuitry  38  of  FIG.  4    may identify a desired beam pointing angle for the signal beam of phased antenna array  36  and may adjust the control signals S provided to phased antenna array  36  to configure phased antenna array  36  to form (steer) the signal beam at that beam pointing angle. Each possible beam pointing angle that can be used by phased antenna array  36  during wireless communications may be identified by a beam steering codebook such as codebook  40 . Codebook  40  may be stored at control circuitry  38 , elsewhere on device  10 , or may be located (offloaded) on external equipment and conveyed to device  10  over a wired or wireless communications link. 
     Codebook  40  may identify each possible beam pointing angle that may be used by phased antenna array  36 . Control circuitry  38  may store or identify phase and magnitude settings for phase and magnitude controllers  33  to use in implementing each of those beam pointing angles (e.g., control circuitry  38  or codebook  40  may include information that maps each beam pointing angle for phased antenna array  36  to a corresponding set of phase and magnitude values for phase and magnitude controllers  33 ). Codebook  40  may be hard-coded or soft-coded into control circuitry  38  or elsewhere in device  10 , may include one or more databases stored at control circuitry  38  or elsewhere in device  10  (e.g., codebook  40  may be stored as software code), may include one or more look-up-tables at control circuitry  38  or elsewhere in device  10 , and/or may include any other desired data structures stored in hardware and/or software on device  10 . Codebook  40  may be generated during calibration of device  10  (e.g., during design, manufacturing, and/or testing of device  10  prior to device  10  being received by an end user) and/or may be dynamically updated over time (e.g., after device  10  has been used by an end user). 
     Control circuitry  38  may generate control signals S based on codebook  40 . For example, control circuitry  38  may identify a beam pointing angle that would be needed to communicate with external wireless equipment  10 ′ of  FIG.  3    (e.g., a beam pointing angle pointing towards external wireless equipment  10 ′). Control circuitry  38  may subsequently identify the beam pointing angle in codebook  40  that is closest to this identified beam pointing angle. Control circuitry  38  may use codebook  40  to generate phase and magnitude values for phase and magnitude controllers  33 . Control circuitry  38  may transmit control signals S identifying these phase and magnitude values to phase and magnitude controllers  33  over control paths  34 . The beam formed by phased antenna array  36  using control signals S will be oriented at the beam pointing angle identified by codebook  40 . If desired, control circuitry  38  may sweep over some or all of the different beam pointing angles identified by codebook  40  until the external wireless equipment is found and may use the corresponding beam pointing angle at which the external wireless equipment was found to communicate with the external wireless equipment (e.g., over communications link  31  of  FIG.  3   ). 
     A schematic diagram of an antenna  30  that may be formed in phased antenna array  36  (e.g., as antenna  30 - 1 ,  30 - 2 ,  30 - 3 , and/or  30 -N in phased antenna array  36  of  FIG.  4   ) is shown in  FIG.  5   . As shown in  FIG.  5   , antenna  30  may be coupled to transceiver circuitry  42  (e.g., millimeter wave transceiver circuitry  28  of  FIG.  3   ). Transceiver circuitry  42  may be coupled to antenna feed  48  of antenna  30  using radio-frequency transmission line path  32 . Antenna feed  48  may include a positive antenna feed terminal such as positive antenna feed terminal  50  and may include a ground antenna feed terminal such as ground antenna feed terminal  52 . Radio-frequency transmission line path  32  may include a positive signal conductor such as signal conductor  44  that is coupled to positive antenna feed terminal  50  and a ground conductor such as ground conductor  46  that is coupled to ground antenna feed terminal  52 . 
     Any desired antenna structures may be used for implementing antenna  30 . In one suitable arrangement that is sometimes described herein as an example, stacked patch antenna structures may be used for implementing antenna  30 . Antennas  30  that are implemented using stacked patch antenna structures may sometimes be referred to herein as stacked patch antennas or simply as patch antennas.  FIG.  6    is a top view of an illustrative patch antenna that may be used in phased antenna array  36 . 
     As shown in  FIG.  6   , antenna  30  may have an antenna radiating element that includes patch element  58 . Patch element  58  (sometimes referred to herein as patch  58  or conductive patch  58 ) may be formed from conductive traces on an underlying substrate or from any other desired conductive materials. Patch element  58  may be separated from and extend parallel to an antenna ground (not shown in  FIG.  6    for the sake of clarity). 
     Patch element  58  may have edges (sides)  66 . The length of edges  66  may be selected so that antenna  30  resonates (radiates) at desired operating frequencies. In one suitable arrangement that is described herein as an example, patch element  58  is a square patch having edges  66  of length L1 (e.g., where patch element  58  has a first pair of parallel edges  66  and a second pair of parallel edges  66  extending orthogonal to and between the first pair of parallel edges  66 ). Length L1 may be selected to be approximately equal to half of the wavelength of the signals conveyed by antenna  30  (e.g., the effective wavelength given the dielectric properties of the materials surrounding patch element  58 ). In one suitable arrangement, this length may be between 0.8 mm and 1.2 mm (e.g., approximately 1.1 mm) for covering a millimeter wave frequency band between 57 GHz and 70 GHz, as just one example. The example of  FIG.  6    merely illustrative. If desired, patch element  58  may have a non-square rectangular shape having two edges of length L1 and having two edges of a different length (e.g., for covering multiple frequency bands). In general, patch element  58  may be formed in any desired shape having any desired number of straight and/or curved edges. 
     To enhance the polarizations handled by antenna  30 , antenna  30  may be provided with multiple antenna feeds. As shown in  FIG.  6   , antenna  30  may include a first antenna feed having positive antenna feed terminal  50 A and may include a second antenna feed having positive antenna feed terminal  50 B. Positive antenna feed terminals  50 A and  50 B may be coupled to transceiver circuitry  42  ( FIG.  5   ) using respective radio-frequency transmission line paths  32 , for example. Positive antenna feed terminals  50 A and  50 B may be coupled to patch element  58 . 
     When using positive antenna feed terminal  50 A, antenna  30  may transmit and/or receive radio-frequency signals with a first polarization (e.g., a first linear polarization). When using positive antenna feed terminal  50 B, antenna  30  may transmit and/or receive radio-frequency signals with a second polarization (e.g., a second linear polarization). The second polarization may be orthogonal to the first polarization. This is merely illustrative and, if desired, positive antenna feed terminals  50 A and  50 B may be used to convey radio-frequency signals with other polarizations (e.g., elliptical polarizations, circular polarizations, etc.). Antenna  30  may include only one of positive antenna feed terminals  50 A or  50 B if desired (e.g., antenna  30  need not be a dual-polarization antenna). 
     In order to increase the bandwidth of antenna  30 , antenna  30  may include one or more parasitic elements layered over (e.g., overlapping) patch element  58 . As shown in  FIG.  6   , a parasitic antenna resonating element such as parasitic patch  68  may be formed from conductive traces layered over patch element  58 . Patch element  58  may, for example, be formed from conductive traces patterned onto a first layer of a dielectric substrate whereas parasitic patch  68  is formed from conductive traces patterned onto a second layer of the dielectric substrate (e.g., where the first and second layers are vertically stacked on top of each other in the direction of the Z-axis of  FIG.  6   ). 
     Parasitic patch  68  may sometimes be referred to herein as parasitic resonating element  68 , parasitic antenna element  68 , parasitic element  68 , parasitic conductor  68 , parasitic structure  68 , or patch  68 . Parasitic patch  68  is not directly fed, whereas patch element  58  is directly fed via positive antenna feed terminals  50 A and  50 B. Parasitic patch  68  may create a constructive perturbation of the electromagnetic field generated by patch element  58 , creating a new resonance for antenna  30 . This may serve to broaden the overall bandwidth of antenna  30  (e.g., to cover an entire frequency band from about 57 GHz to 71 GHz). 
     In one suitable arrangement that is described herein as an example, parasitic patch  68  is a square patch having edges (sides) of length L2. The edges of parasitic patch  68  may be oriented parallel to the edges  66  of patch element  58  (e.g., parasitic patch  68  may be aligned with patch element  58 ). Length L2 may be less than length L1 of patch element  58 . The example of  FIG.  6    merely illustrative. If desired, parasitic patch  68  may have a non-square rectangular shape or any other desired shape having any desired number of straight and/or curved edges. If desired, antenna  30  may include additional parasitic elements that are coplanar with parasitic patch  68 . 
     For example, as shown in  FIG.  6   , antenna  30  may include additional parasitic patches  64  (sometimes be referred to herein as parasitic resonating elements  64 , parasitic antenna elements  64 , parasitic elements  64 , parasitic conductors  64 , parasitic structures  64 , or patches  64 ). Parasitic patches  64  may be coplanar with parasitic patch  102 . Each parasitic patch  64  may be separated from a corresponding edge of parasitic patch  68  by a respective gap  62 . Each parasitic patch  64  may, if desired, overlap a respective edge  66  of the underlying patch element  58 . Each parasitic patch  64  may be the same size and shape, for example. 
     In one suitable arrangement that is described herein as an example, parasitic patches  64  are rectangular patches having edges (sides) that are shorter than length L1 and that are greater than, equal to, or less than length L2. The example of  FIG.  6    merely illustrative. If desired, parasitic patches  64  may have other non-square rectangular shapes or any other desired shapes having any desired number of straight and/or curved edges. Gaps  62  (sometimes referred to herein as openings  62  or slots  62 ) may help to mitigate the trapping of radio-frequency energy between the parasitic elements and patch element  58 , for example. Parasitic patches  64  and  68  may sometimes be referred to herein collectively as single-layer parasitic antenna resonating elements, single-layer parasitic elements, single-layer parasitic patches, or single-layer parasitic structures for antenna  30 . 
     Each antenna  30  in phased antenna array  36  may include a corresponding patch element  58  and overlying single-layer parasitic structures. The antennas  30  in phased antenna array  36  may be arranged in an array pattern having any desired number of rows (e.g., extending along a longitudinal axis parallel to the X-axis) and/or any desired number of columns (e.g., extending along a longitudinal axis parallel to the Y-axis). If care is not taken, the antennas  30  in phased antenna array  36  may exhibit undesirable mutual coupling with one or more adjacent antennas  30  in phased antenna array  36 . Such mutual coupling can undesirably limit the overall antenna efficiency of each antenna  30 . In order to mitigate mutual coupling in phased antenna array  36 , antenna  30  may be diagonally-oriented with respect to the rows and columns of phased antenna array  36  and may include diagonally-oriented positive antenna feed terminals  50 A and  50 B. 
     For example, as shown in  FIG.  6   , patch element  58 , parasitic patch  68 , and parasitic patches  64  may be rotated (e.g., about a central axis  60  extending parallel to the Z-axis) at a non-zero angle with respect to the direction of the rows and columns in phased antenna array  36  (e.g., with respect to the X and Y-axes of  FIG.  6   ). In one suitable arrangement that is described herein as an example, the non-zero angle is 45 degrees. Other non-zero angles may be used if desired (e.g., 40-50 degrees, 35-55 degrees, 44-46 degrees, etc.). 
     Patch element  58  may have a first diagonal axis  54  and a second diagonal axis  56 . Diagonal axis  54  may extend through central axis  60  and a first pair of opposing corners of patch element  58 . Diagonal axis  56  may be perpendicular to diagonal axis  54 . Diagonal axis  56  may extend through central axis  60  and a second pair of opposing corners of patch element  58 . As parasitic patch  68  is also centered about central axis  60 , diagonal axis  56  also passes through a first pair of opposing corners of parasitic patch  68 . Similarly, diagonal axis  54  also passes through a second pair of opposing corners of parasitic patch  68 . 
     When oriented in this way, each of the antennas  30  along a given row of phased antenna array  36  may have a central axis (e.g., central axis  60 ) that intersects the diagonal axis  54  of each antenna  30  in that row of phased antenna array  36 . Similarly, each of the antennas  30  along a given column of phased antenna array  36  may have a central axis that intersects the diagonal axis  56  of each antenna  30  in that column of phased antenna array  36 . In other words, diagonal axis  54  may form the longitudinal axis for a given row of antennas  30  (e.g., where each antenna  30  in the row is aligned along the longitudinal axis for that row) and diagonal axis  56  may form the longitudinal axis for a given column of antennas  30  in phased antenna array  36  (e.g., where each antenna  30  in the column is aligned along the longitudinal axis for that column). When oriented in this way, edges  66  of patch element  58  and the edges of parasitic patch  68  are each oriented at the non-zero angle (e.g., 45 degrees) with respect to diagonal axes  56  and  54  and with respect to the direction (e.g., the longitudinal axes) of the rows and the columns in phased antenna array  36 . 
     Diagonally orienting the antennas  30  in phased antenna array  36  in this way may serve to minimize mutual coupling between the antennas in the phased antenna array, thereby maximizing the overall antenna efficiency of each of the antennas. In order to further mitigate mutual coupling and optimize antenna efficiency (e.g., relative to scenarios where positive antenna feed terminals  50 A and  50 B are located along respective edges  66  of patch element  58 ), positive antenna feed terminal  50 A may be coupled to patch element  58  at a location along diagonal axis  56 . Similarly, positive antenna feed terminal  50 B may be coupled to patch element  58  at a location along diagonal axis  54 . The distance between positive antenna feed terminal  50 A and central axis  60  (e.g., along diagonal axis  56 ) and the distance between positive antenna feed terminal  50 B and central axis  60  (e.g., along diagonal axis  54 ) may be selected to perform impedance matching for antenna  30 , for example. Feeding antenna  30  in this way may also allow antenna  30  to continue to convey linearly-polarized signals (e.g., horizontal and vertically polarized signals) using positive antenna feed terminals  50 A and  50 B, for example. 
       FIG.  7    is a cross-sectional side view of antenna  30  (e.g., as taken in the direction of line AA′ of  FIG.  6   ). As shown in  FIG.  7   , antenna  30  may be formed on a dielectric substrate such as substrate  70 . If desired, each of the antennas in the phased antenna array may be formed on the same dielectric substrate (e.g., in an integrated antenna module having a radio-frequency integrated circuit mounted to substrate  70 ). Substrate  70  may be, for example, a rigid or printed circuit board or another dielectric substrate. Substrate  70  may include multiple stacked dielectric layers  72  (e.g., layers of printed circuit board substrate, layers of fiberglass-filled epoxy, layers of polyimide, layers of ceramic substrate, or layers of other dielectric materials). 
     With this type of arrangement, antenna  30  may be embedded within the layers of substrate  70 . For example, patch element  58  may be formed from conductive traces  92  patterned on a first layer  72  of substrate  70 . Parasitic patches  68  and  64  may be formed from conductive traces  90  patterned on a second layer  72  of substrate  70 . The second layer may be stacked over the first layer of substrate  70 . Zero, one, or more than one additional layer  72  may be vertically interposed between the first and second layers  72  if desired. Gaps  62  in conductive traces  90  may separate parasitic patch  68  from parasitic patches  64 . 
     Antenna  30  may have an antenna ground that includes ground traces  74  (e.g., a ground plane for antenna  30 ). The same ground traces  74  may be used to form the antenna ground for each antenna in the phased antenna array if desired. Patch element  92  may be separated from and may extend parallel to ground traces  74 . One or more layers  72  of substrate  70  may be vertically interposed between ground traces  74  and patch element  58 . Zero, one, or more than one layer  72  in substrate  70  may be vertically interposed between conductive traces  90  and the exterior of substrate  70 . 
     Ground traces  74  may have openings such as opening  76 . Signal traces  80  may be patterned on one or more of the layers  72  in substrate  70  (e.g., ground traces  74  may be vertically interposed between signal traces  80  and patch element  58 ). Signal traces  80  may, for example, form the signal conductor of the radio-frequency transmission line path for antenna  30  (e.g., signal conductor  44  in radio-frequency transmission line path  32  of  FIG.  5   ). A conductive via such as conductive via  78  may couple signal traces  80  to patch element  58  (e.g., at positive antenna feed terminal  50 B). Similar feeding structures may be used to feed positive antenna feed terminal  50 A ( FIG.  6   ). As shown in  FIG.  7   , parasitic patches  68  and  64  are not directly fed by positive antenna feed terminal  50 B. 
       FIG.  8    is a plot of antenna performance (mutual coupling) as a function of frequency for a given antenna  30  in phased antenna array  36  ( FIG.  6   ). As shown in  FIG.  8   , curve  94  plots the mutual coupling of antenna  30  in scenarios where the antennas are not rotated by the non-zero angle with respect to the X and Y axes of  FIG.  6    and where the antennas are fed using positive antenna feed terminals  50 A and  50 B located along orthogonal edges  66  of patch element  58 . 
     Curve  98  plots the mutual coupling of antenna  30  in scenarios where the antennas in the phased antenna array are oriented and fed as shown in  FIG.  6   . As shown by curves  98  and  94 , rotating the antenna elements and feeding the antenna along diagonal axes  54  and  56  may serve to reduce mutual coupling across the frequency band of operation of antenna  30 , as shown by arrow  96 . This reduction in mutual coupling may serve to increase the overall antenna efficiency of antenna  30 , for example. The example of  FIG.  8    is merely illustrative. In practice, curves  94  and  98  may have other shapes. Antenna  30  may convey radio-frequency signals at any desired frequencies (e.g., frequencies greater than 10 GHz). 
     In the example of  FIGS.  6 - 8   , the parasitic patches in antenna  30  are confined to a single layer  72  of substrate  70 . If desired, the parasitic patches in antenna  30  may be distributed across two or more layers  72  of substrate  70 .  FIG.  9    is a top view of an antenna  30  having parasitic patches distributed across multiple layers of the substrate. 
     As shown in  FIG.  9   , antenna  30  may include a parasitic patch such as parasitic patch  102  (sometimes referred to herein as parasitic resonating element  102 , parasitic antenna element  102 , parasitic element  102 , parasitic conductor  102 , parasitic structure  102 , or patch  102 ). Parasitic patch  102  and patch element  58  may be centered about central axis  60 . In one suitable arrangement that is described herein as an example, parasitic patch  102  is a square patch having edges (sides) of length L3. Length L3 may be less than the length of the edges of patch element  58  (e.g., length L1 as shown in  FIG.  6   ). The edges of parasitic patch  102  may be oriented parallel to the edges of patch element  58  (e.g., parasitic patch  102  may be aligned with patch element  58 ). The example of  FIG.  9    merely illustrative. If desired, parasitic patch  102  may have a non-square rectangular shape or any other desired shape having any desired number of straight and/or curved edges. 
     Antenna  30  may also include additional parasitic patches  104  (sometimes be referred to herein as parasitic resonating elements  104 , parasitic antenna elements  104 , parasitic elements  104 , parasitic conductors  104 , parasitic structures  104 , or patches  104 ). Parasitic patches  104  may be located at a different distance from patch element  58  than parasitic patch  102 . For example, parasitic patches  104  may be located at a first distance from (over) patch element  58  whereas parasitic patch  102  is located at a second distance that is greater than the first distance from patch element  58 . Each parasitic patch  104  may be separated from an opposing parasitic patch  104  by gap  100 . Gap  100  may overlap patch element  58  and central axis  60 . Parasitic patch  102  may overlap gap  100 . In the example of  FIG.  9   , parasitic patch  102  is non-overlapping with respect to parasitic patches  104 . In another suitable arrangement, parasitic patches  104  may partially overlap parasitic patch  102 . Each parasitic patch  104  may, if desired, overlap a respective edge of the underlying patch element  58 . 
     If desired, each parasitic patch  104  may be the same size and shape. In one suitable arrangement that is described herein as an example, parasitic patches  104  are rectangular patches having edges (sides) that are shorter than length L1 ( FIG.  6   ) and that are greater than, equal to, or less than length L3. Each parasitic patch  104  may have edges that are oriented parallel to the edges of patch element  58  and parasitic patch  102 . The example of  FIG.  9    merely illustrative. If desired, parasitic patches  104  may have other rectangular shapes or any other desired shapes having any desired number of straight and/or curved edges. Parasitic patches  104  and  102  may sometimes be referred to herein collectively as multi-layer parasitic antenna resonating elements, multi-layer parasitic elements, multi-layer parasitic patches, or multi-layer parasitic structures for antenna  30 . 
     In the example of  FIG.  9   , the edges of parasitic patches  104  and  102  and the edges of patch element  58  are oriented parallel to the direction of the rows and columns in phased antenna array  36 . Positive antenna feed terminals  50 A and  50 B may be coupled to patch element  58  along orthogonal edges of patch element  58 . This example is merely illustrative. In another suitable arrangement, parasitic patches  104  and  102  and patch element  58  may be rotated at a non-zero (e.g., 45 degree) angle with respect to the direction of the rows and columns in phased antenna array  36  and patch element  58  may be fed along the diagonal axes of patch element  58  (e.g., antenna  30  may be rotated and fed as shown in  FIG.  6    but may include the multi-layer parasitic structures of  FIG.  9   ). 
       FIG.  10    is a cross-sectional side view of antenna  30  having multi-layer parasitic structures (e.g., as taken in the direction of line BB′ of  FIG.  9   ). As shown in  FIG.  10   , patch element  58  may be formed from conductive traces  92  patterned on a first layer  72  of substrate  70 . Parasitic patches  104  may be formed from conductive traces  108  patterned on a second layer  72  of substrate  70 . The second layer may be stacked over the first layer of substrate  70 . Zero, one, or more than one additional layer  72  may be vertically interposed between the first and second layers  72  if desired. Parasitic patch  102  may be formed from conductive traces  106  patterned on a third layer  72  of substrate  70 . The third layer may be stacked over the second layer of substrate  70 . Zero, one, or more than one additional layer  72  may be vertically interposed between the second and third layers  72  if desired. 
     Parasitic patches  104  may be separated by gap  100  overlapping patch element  58 . Parasitic patch  102  may overlap gap  100  and patch element  58 . Patch element  58  may be directly fed whereas parasitic patches  104  and  102  are not directly fed (e.g., each of the parasitic patches is floating). First capacitances may be established between parasitic patch  102  and each of the parasitic patches  104 . Second capacitances may be established between each of the parasitic patches  104  and patch element  58 . These capacitances may serve to increase the total capacitance between patch element  58  and the upper-most parasitic patch relative to arrangements where antenna  30  includes single-layer parasitic structures, which may allow antenna  30  to exhibit an even more compact volume relative to arrangements where antenna  30  includes single-layer parasitic structures, for example. 
     When arranged in this way, the parasitic patches may provide freedom to fine tune the radio-frequency performance of antenna  30  for compensating for changes in dielectric thickness, dielectric constant, radome material (e.g., for a radome placed over antenna  30 ), copper thickness, etc., without changing the antenna radiation mechanism or radiation pattern. In other words, the lateral footprint of antenna  30  of  FIGS.  9  and  10    (e.g., as defined by a square running through the outer-most edges of parasitic patches  104  as shown in  FIG.  9   ) may be smaller than the lateral footprint of antenna  30  of  FIGS.  6  and  7    (e.g., as defined by a rotated square running through the outer-most edges of parasitic patches  64  as shown in  FIG.  6   ). Conversely, when antenna  30  of  FIGS.  9  and  10    is configured to exhibit the same lateral footprint as antenna  30  of  FIGS.  6  and  7   , antenna  30  may exhibit increased bandwidth relative to antenna  30  of  FIGS.  6  and  7   . 
       FIG.  11    is a plot of antenna performance (return loss) as a function of frequency for a given antenna  30  (e.g., an antenna  30  having a given lateral footprint). As shown in  FIG.  11   , curve  110  plots the return loss of an antenna  30  having single-layer parasitic structures (e.g., antenna  30  of  FIGS.  6  and  7   ). Curve  112  plots the return loss of an antenna  30  having multi-layer parasitic structures (e.g., antenna  30  of  FIGS.  9  and  10   ). As shown by curves  110  and  112 , antenna  30  may exhibit satisfactory return loss (e.g., a return loss less than threshold level TH) across the frequency band of operation of the antenna. However, forming antenna  30  using multi-layer parasitic structures (e.g., as shown in  FIGS.  9  and  10   ) may further reduce the return loss of the antenna, as shown by arrow  114 . 
     The example of  FIG.  11    is merely illustrative. In practice, curves  110  and  112  may have other shapes. Antenna  30  may convey radio-frequency signals at any desired frequencies (e.g., frequencies greater than 10 GHz). 
     Device  10  may gather and/or use personally identifiable information. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20220523
Publication Date: 20240206
Grant Date: 20240206
Priority Date: 20200922
Inventors: WU, JIANGFENG
ZHANG, LIJUN
PASCOLINI, MATTIA
YONG, Siwen
JIANG, YI
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q5/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/523", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q3/34", "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": true, "tree": "[]"}, {"code": "H01Q1/523", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q5/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q3/34", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q19/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0414", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80740914