PATENT DOCUMENT

Publication Number: US-11289802-B2
Application Number: US-201916413508-A
Country: US
Kind Code: B2

Title: Millimeter wave impedance matching structures

Abstract:
An electronic device may be provided with a transceiver, a substrate, and antennas mounted to the substrate. The transceiver and antennas may convey signals between 10 GHz and 300 GHz. A radio-frequency connector may be mounted to the substrate. A coaxial cable may couple the transceiver to the connector. A stripline in the substrate may couple the connector to the antennas. Impedance matching structures may be embedded in the substrate for matching an impedance of the stripline to an impedance of the coaxial cable. The impedance matching structures may include a fence of conductive vias, landing pads, and a volume of the dielectric substrate defined by the fence of conductive vias and the landing pads. The impedance matching structures may be configured to perform impedance matching over a relatively wide bandwidth that includes the frequency band of operation for the antennas.

Claims:
What is claimed is: 
     
       1. An antenna module configured to be coupled to a transceiver using a first transmission line, the antenna module comprising:
 a dielectric substrate; 
 an antenna on the dielectric substrate and configured to convey radio-frequency signals at a frequency between 10 GHz and 300 GHz; 
 a second transmission line embedded in the dielectric substrate; 
 a radio-frequency connector mounted to the dielectric substrate, wherein the radio-frequency connector is configured to receive the first transmission line; and 
 impedance matching structures that are embedded in the dielectric substrate and that couple the second transmission line to the radio-frequency connector, the impedance matching structures comprising a fence of conductive vias that is coupled to a grounded body portion of the radio-frequency connector, wherein the impedance matching structures are configured to match an impedance of the first transmission line to an impedance of the second transmission line. 
 
     
     
       2. The antenna module defined in  claim 1 , wherein the first transmission line comprises a coaxial cable. 
     
     
       3. The antenna module defined in  claim 2 , wherein the second transmission line comprises a stripline. 
     
     
       4. The antenna module defined in  claim 1 , wherein the second transmission line comprises a stripline. 
     
     
       5. The antenna module defined in  claim 1 , wherein the fence of conductive vias is ring-shaped, and a volume of the dielectric substrate has a diameter defined by the ring-shaped fence of conductive vias. 
     
     
       6. The antenna module defined in  claim 5 , further comprising a contact pad on a surface of the dielectric substrate, wherein the contact pad is coupled to a signal body portion of the radio-frequency connector. 
     
     
       7. The antenna module defined in  claim 6 , wherein the second transmission line comprises signal traces in the dielectric substrate, the antenna module further comprising:
 a conductive via that couples the signal traces to the contact pad. 
 
     
     
       8. The antenna module defined in  claim 7 , wherein the impedance matching structures further comprise landing pads coupled to the conductive via, wherein the landing pads define at least part of the volume. 
     
     
       9. The antenna module defined in  claim 1 , wherein the dielectric substrate comprises a first dielectric layer, a second dielectric layer, and a third dielectric layer, the second dielectric layer being interposed between the first and third dielectric layers, the antenna module further comprising:
 first ground traces on the first dielectric layer; 
 signal traces on the second dielectric layer; and 
 second ground traces on the third dielectric layer, wherein the signal traces and at least part of the first and second ground traces form the second transmission line. 
 
     
     
       10. The antenna module defined in  claim 9 , wherein the fence of conductive vias couple the first ground traces to the second ground traces and a volume of the first, second, and third dielectric layers is defined at least in part by the fence of conductive vias. 
     
     
       11. The antenna module defined in  claim 10 , wherein the radio-frequency connector is mounted to the second ground traces. 
     
     
       12. The antenna module defined in  claim 10 , further comprising:
 a fourth dielectric layer interposed between the radio-frequency connector and the second ground traces; and 
 third ground traces on the fourth dielectric layer, wherein the fence of conductive vias is coupled to the third ground traces, the radio-frequency connector being mounted to the third ground traces. 
 
     
     
       13. Apparatus comprising:
 a dielectric substrate; 
 an antenna on the dielectric substrate and configured to convey radio-frequency signals at a frequency between 10 GHz and 300 GHz; 
 a stripline having first ground traces, second ground traces, and signal traces, the signal traces being coupled to the antenna and extending between the first and second ground traces; and 
 impedance matching structures embedded in the dielectric substrate and coupled to the stripline, wherein the impedance matching structures are configured to match an impedance of the stripline to an impedance of a transmission line external to the dielectric substrate. 
 
     
     
       14. The apparatus defined in  claim 13 , further comprising a contact pad at a surface of the dielectric substrate and a conductive via coupled to the contact pad and extending through the dielectric substrate, wherein
 the signal traces are coupled to the conductive via. 
 
     
     
       15. The apparatus defined in  claim 14 , further comprising:
 a fence of conductive vias that couples the first ground traces to the second ground traces and that laterally surrounds the conductive via; and 
 a landing pad on the dielectric substrate and coupled to the conductive via at a location between the signal traces and the contact pad, wherein the impedance matching structures comprise the fence of conductive vias, the landing pad, and a volume of the dielectric substrate defined by the fence of conductive vias and the landing pad. 
 
     
     
       16. The apparatus defined in  claim 15 , wherein a dielectric constant of the dielectric substrate within the volume, a width of the landing pad, and a diameter of the fence of conductive vias are selected to configure the impedance matching structures to match the impedance of the stripline to the impedance of the transmission line external to the dielectric substrate. 
     
     
       17. The apparatus defined in  claim 16 , further comprising:
 a radio-frequency connector mounted to the dielectric substrate and configured to receive the transmission line external to the dielectric substrate, wherein the transmission line external to the dielectric substrate comprises a coaxial cable, the radio-frequency connector comprising a signal body portion coupled to the contact pad and a grounded body portion coupled to the first ground traces by the fence of conductive vias. 
 
     
     
       18. Apparatus comprising:
 a dielectric substrate; 
 ground traces on the dielectric substrate; 
 a radio-frequency connector on a surface of the dielectric substrate; 
 a coaxial cable coupled to the radio-frequency connector; 
 a stripline in the dielectric substrate; 
 a conductive via that couples a signal conductor of the stripline to the radio-frequency connector; 
 a landing pad in the dielectric substrate and coupled to the conductive via; and 
 a fence of conductive vias that couple the radio-frequency connector to the ground traces, wherein the fence of conductive vias runs around the conductive via and the landing pad, the landing pad and the fence of conductive vias defining a volume of the dielectric substrate that is configured to match an impedance of the stripline to an impedance of the coaxial cable. 
 
     
     
       19. The apparatus defined in  claim 18 , further comprising:
 additional ground traces in the dielectric substrate, wherein the fence of conductive vias couples the ground traces to the additional ground traces, and the signal conductor of the stripline extends between the ground traces and the additional ground traces.

Description:
This application claims the benefit of provisional patent application No. 62/831,110, filed Apr. 8, 2019, 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. Radio-frequency transmission line paths are coupled between the wireless transceivers and the antennas. 
     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 the antennas can be characterized by substantial attenuation and/or distortion during signal propagation. In addition, impedance discontinuities on the radio-frequency transmission line paths can produce substantial signal reflection at these frequencies, limiting the overall efficiency of the wireless communications circuitry. 
     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 radio-frequency transceiver circuitry and an antenna module. The antenna module may include a dielectric substrate and one or more antennas mounted to the dielectric substrate. The radio-frequency transceiver circuitry and the antennas may convey radio-frequency signals between 10 GHz and 300 GHz. 
     A radio-frequency connector may be mounted to a surface of the dielectric substrate. A first radio-frequency transmission line such as a coaxial cable may couple the radio-frequency transceiver circuitry to the radio-frequency connector. A second radio-frequency transmission line such as a stripline may be embedded in the dielectric substrate. The stripline may couple the radio-frequency connector to at least one of the antennas. 
     Impedance matching structures may be embedded within the dielectric substrate and may be coupled between the stripline and the radio-frequency connector. A conductive via may couple a signal conductor of the stripline to a signal body portion of the radio-frequency connector. Landing pads may be interposed on the conductive via between the signal body portion of the radio-frequency connector and the signal conductor of the stripline. A ring-shaped fence of conductive vias may couple ground traces in the stripline to a grounded body portion of the radio-frequency connector. The fence of conductive vias may laterally surround the conductive via and the landing pads. The impedance matching structures may include the fence of conductive vias, the landing pads, and a volume of the dielectric substrate defined by the landing pads and the conductive vias. The width of the landing pads, the diameter of the fence of conductive vias, and the dielectric constant of the dielectric substrate within the volume may be selected to match an impedance of the stripline to an impedance of the coaxial cable. The impedance matching structures may perform impedance matching in this way over a relatively large bandwidth that includes the frequency band of operation for the antenna module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a 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 schematic diagram showing how illustrative millimeter and centimeter wave transceiver circuitry may be coupled to an antenna using a radio-frequency transmission line path in accordance with some embodiments. 
         FIG. 5  is a perspective view of an illustrative patch antenna in accordance with some embodiments. 
         FIG. 6  is a perspective view of an illustrative antenna module having impedance matching structures for matching the impedance of a coaxial cable and connector to the impedance of a transmission line within the antenna module in accordance with some embodiments. 
         FIG. 7  is a top view of an illustrative radio-frequency connector mounted to ground traces at a surface of an antenna module in accordance with some embodiments. 
         FIGS. 8 and 9  are cross-sectional side views of illustrative antenna modules having impedance matching structures for matching the impedance of a coaxial cable and connector to the impedance of a stripline within the antenna module in accordance with some embodiments. 
         FIG. 10  is a top view of an illustrative antenna module having impedance matching structures for matching the impedance of a coaxial cable and connector to the impedance of a stripline within the antenna module in accordance with some embodiments. 
         FIG. 11  is a plot of reflection coefficient as a function of frequency for impedance matching structures of the type shown in  FIGS. 6-10  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 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 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 , under a dielectric window on a rear face of housing  12  or the edge of housing  12 , 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 dielectric. 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) communications bands between 27 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. 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. 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 . Non-millimeter/centimeter wave transceiver circuitry  26  may include wireless local area network (WLAN) transceiver circuitry that handles 2.4 GHz and 5 GHz bands for Wi-Fi® (IEEE 802.11) communications, wireless personal area network (WPAN) transceiver circuitry that handles the 2.4 GHz Bluetooth® communications band, cellular telephone transceiver circuitry that handles cellular telephone communications bands from 700 to 960 MHz, 1710 to 2170 MHz, 2300 to 2700 MHz, and/or or any other desired cellular telephone communications bands between 600 MHz and 4000 MHz, GPS receiver circuitry that receives GPS signals at 1575 MHz or signals for handling other satellite positioning data (e.g., GLONASS signals at 1609 MHz), television receiver circuitry, AM/FM radio receiver circuitry, paging system transceiver circuitry, near field communications (NFC) circuitry, etc. 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. 
     Wireless circuitry  24  may include antennas  30 . Non-millimeter/centimeter wave transceiver circuitry  26  may transmit and receive radio-frequency signals below 10 GHz using one or more antennas  30 . Millimeter/centimeter wave transceiver circuitry  28  may transmit and receive radio-frequency signals above 10 GHz (e.g., at millimeter wave and/or centimeter wave frequencies) using antennas  30 . 
     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 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. 
     A schematic diagram of an antenna  30  that may be formed in a phased antenna array for conveying radio-frequency signals at millimeter and centimeter wave frequencies is shown in  FIG. 4 . As shown in  FIG. 4 , antenna  30  may be coupled to millimeter/centimeter (MM/CM) wave transceiver circuitry  28 . Millimeter/centimeter wave transceiver circuitry  28  may be coupled to antenna feed  34  of antenna  30  using radio-frequency transmission line path  32 . Antenna feed  34  may include a positive antenna feed terminal such as positive antenna feed terminal  36  and may include a ground antenna feed terminal such as ground antenna feed terminal  38 . Radio-frequency transmission line path  32  (sometimes referred to herein as transmission line path  32 ) may include a positive signal path such as signal path  40  that is coupled to positive antenna feed terminal  36 . Radio-frequency transmission line path  32  may include a ground signal path such as ground path  42  that is coupled to ground antenna feed terminal  38 . 
     Radio-frequency transmission line path  32  may include one or more (radio-frequency) transmission lines. Radio-frequency transmission line path  32  may also include one or more radio-frequency connectors that couple the transmission lines in radio-frequency transmission line path  32  together. Signal path  40  may include the signal conductor of each transmission line in radio-frequency transmission line path  32 . Ground path  42  may include the ground conductor of each transmission line in radio-frequency transmission line path  32 . The transmission lines used to form radio-frequency transmission line path  32  may include coaxial cables, coaxial probes realized by metalized vias, microstrip transmission lines, stripline transmission lines (sometimes referred to herein simply as striplines), edge-coupled microstrip transmission lines, edge-coupled striplines, waveguide structures, coplanar waveguide structures, grounded coplanar waveguide structures, combinations of these, etc. 
     Multiple types of transmission lines may be used to form radio-frequency transmission line path  32 . In one suitable arrangement that is sometimes described herein as an example, radio-frequency transmission line path  32  may include a coaxial cable, a stripline, and a radio-frequency connector that couples the stripline to the coaxial cable. The coaxial cable, the stripline, and the radio-frequency connector may convey radio-frequency signals at millimeter and centimeter wave frequencies for millimeter/centimeter wave transceiver circuitry  28  and antenna  30 . 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  and/or coupled to antenna  30 , if desired. 
     One or more of the transmission lines in radio-frequency transmission line path  32  may be integrated into ceramic substrates, rigid printed circuit boards, and/or flexible printed circuits. In another suitable arrangement, one or more of the 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). 
     Device  10  may contain multiple antennas  30 . 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  ( FIG. 3 ) 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 antennas  30 . Antenna adjustments may be made to tune the antennas to radiate 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  30  to gather sensor data in real time that is used in adjusting antennas  30 . 
     In some configurations, antennas  30  may be arranged in one or more antenna arrays (e.g., phased antenna arrays that implement beam steering functions). For example, the antennas that are used in handling millimeter and centimeter wave signals may be implemented as a phased antenna array. Control circuitry  14  ( FIG. 3 ) may perform beam steering functions using the phased antenna array by adjusting the phase and magnitude provided to each antenna in the phased antenna array (e.g., so that signals for each antenna constructively and destructively interfere such that the phased antenna array transmits or receives radio-frequency signals with a peak gain in a desired direction). The radiating elements in a phased antenna array for supporting millimeter and centimeter wave communications may be patch antennas (e.g., stacked 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. 
     An illustrative patch antenna that may be used in conveying radio-frequency signals at frequencies between 10 GHz and 300 GHz is shown in  FIG. 5 . As shown in  FIG. 5 , antenna  30  may be a patch antenna having a patch antenna resonating element  44  that is separated from and parallel to a ground plane such as antenna ground  46 . Positive antenna feed terminal  36  may be coupled to patch antenna resonating element  44 . Ground antenna feed terminal  38  may be coupled to antenna ground  46 . If desired, conductive path  48  (e.g., a coaxial probe feed) may be used to couple terminal  36 ′ to terminal  36  so that antenna  30  is fed using a transmission line with a signal conductor coupled to terminal  36 ′ and thus terminal  36 . If desired, path  48  may be omitted and other types of antenna feed arrangements may be used. The illustrative feeding configuration of  FIG. 5  is merely illustrative. 
     As shown in  FIG. 5 , patch antenna resonating element  44  may lie within a plane such as the X-Y plane of  FIG. 5  (e.g., the lateral surface area of patch antenna resonating element  44  may lie in the X-Y plane). Patch antenna resonating element  44  may sometimes be referred to herein as patch  44 , patch element  44 , patch resonating element  44 , patch radiating element  44 , antenna resonating element  44 , or resonating element  44 . Antenna ground  46  may lie within a plane that is parallel to the plane of patch element  44 . Patch element  44  and antenna ground  46  may therefore lie in separate parallel planes that are separated by a distance H. Patch element  44  and antenna ground  46  may be formed from conductive traces patterned on a dielectric substrate such as a rigid or flexible printed circuit board substrate or a ceramic substrate, metal foil, stamped sheet metal, electronic device housing structures, or any other desired conductive structures. The length of the sides of patch element  44  may be selected so that antenna  30  resonates at a desired operating frequency/wavelength. For example, the sides of patch element  44  may each have a length L that is approximately equal to half of the effective wavelength (e.g., within 15% of half of the effective wavelength) of the radio-frequency signals conveyed by antenna  30  (e.g., in scenarios where patch element  44  is substantially square). The effective wavelength of the radio-frequency signals is equal to the free-space wavelength of the radio-frequency signals multiplied by a constant factor that is determined by the dielectric material surrounding patch element  44 . 
     The example of  FIG. 5  is merely illustrative. Patch element  44  may have a square shape in which all of the sides of patch element  44  are the same length or may have a different rectangular shape (e.g., a non-square rectangular shape). Patch element  44  may cover multiple frequency bands in scenarios where patch element  44  has a rectangular shape. A parasitic patch antenna resonating element may be located above patch element  44  if desired. The parasitic patch antenna resonating element may serve to broaden the bandwidth of patch element  44 , for example. If desired, patch element  44  and antenna ground  46  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 the example of  FIG. 5 , antenna  30  is fed using a single positive antenna feed terminal  36 . If desired, antenna  30  may be fed using multiple positive antenna feed terminals. Each positive antenna feed terminal may be fed using a different radio-frequency transmission line path and may cover a different orthogonal polarization, for example. Antenna  30  need not be a patch antenna and, in general, other types of antenna structures may be used to implement antenna  30 . 
     Multiple antennas  30  (e.g., multiple antennas in a given phased antenna array) may be mounted to the same substrate. Other circuitry such as a radio-frequency integrated circuit may also be mounted to the substrate to form an integrated antenna module.  FIG. 6  is a perspective view of an integrated antenna module for handling signals between 10 and 300 GHz in device  10 . 
     As shown in  FIG. 6 , device  10  may be provided with an integrated antenna module such as integrated antenna module  50  (sometimes referred to herein as antenna module  50  or module  50 ). Antenna module  50  may include one or more antennas  30  (e.g., antennas in a phased antenna array) on a dielectric substrate such as dielectric substrate  58 . In the example of  FIG. 6 , a single patch element  44  of a corresponding antenna  30  is mounted to bottom surface  62  of dielectric substrate  58 . This is merely illustrative. If desired, patch element  44  may be embedded within dielectric substrate  58 , may be formed on top surface  60  of dielectric substrate  58 , and/or may be replaced with other types of antenna resonating element structures. Antenna module  50  may include more than one antenna  30  if desired (e.g., an N-by-M array of antennas  30  arranged in a phased antenna array). Antenna module  50  may be mounted at any desired location within electronic device  10  of  FIG. 1 . In another suitable arrangement, antenna module  50  may be used in a wireless test system to test the radio-frequency performance of antenna  30  (e.g., antenna module  50  may be a test or validation coupon used to test and/or validate the radio-frequency performance of different designs or assemblies of antenna  30  and/or dielectric substrate  58 ). 
     Dielectric substrate  58  may be, for example, a rigid or flexible printed circuit board or another dielectric substrate such as a ceramic substrate. Dielectric substrate  58  may be a stacked dielectric substrate that includes multiple stacked dielectric layers  64  (e.g., multiple layers of printed circuit board substrate such as multiple layers of fiberglass-filled epoxy, rigid printed circuit board material, flexible printed circuit board material, ceramic, plastic, glass, or other dielectrics). Conductive traces formed on dielectric layers  64  may be used in implementing the antenna ground for antenna  30  (e.g., antenna ground  46  of  FIG. 5 ), the antenna resonating element for antenna  30  (e.g., patch element  44 ), parts of the radio-frequency transmission line paths for antennas  30  (e.g., signal path  40  and/or ground path  42  in radio-frequency transmission line path  32  of  FIG. 4 ), etc. Conductive vias may extend vertically through one or more dielectric layers  64  (e.g., in the direction of the Z-axis of  FIG. 6 ) to couple conductive traces on different dielectric layers  64  together. 
     If desired, one or more electrical components may be mounted to top surface  60  of dielectric substrate  58  (not shown in  FIG. 6  for the sake of clarity). These components may include, for example, an integrated circuit (e.g., an integrated circuit chip) or other circuitry mounted to top surface  60  of dielectric substrate  58 . In another suitable arrangement, these components may be embedded within dielectric substrate  58  or formed on bottom surface  62  of dielectric substrate  58 . These components may include radio-frequency components such as amplifier circuitry, phase shifter circuitry, and other circuitry that operates on the radio-frequency signals conveyed by antenna  30 . 
     Antenna module  50  may convey radio-frequency signals to and from transceiver circuitry (e.g., millimeter/centimeter wave transceiver circuitry  28  of  FIG. 3 ) over one or more radio-frequency transmission line paths (e.g., radio-frequency transmission line paths  32  of  FIG. 4 ). Each radio-frequency transmission line path may include a first transmission line  68  embedded within dielectric substrate  58 , a second transmission line  54  external to dielectric substrate  58 , and a radio-frequency connector  52  that couples the first transmission line  68  to the second transmission line  54  (e.g., first transmission line  68 , radio-frequency connector  52 , and second transmission line  54  may collectively form one radio-frequency transmission line path  32  of  FIG. 4 ). Radio-frequency connector  52  may be mounted to top surface  60  of dielectric substrate  58 . While only a single radio-frequency connector and transmission line path is shown in  FIG. 6  for the sake of clarity, in general, antenna module  50  may include any desired number of transmission line paths and radio-frequency connectors. 
     First transmission line  68  and second transmission line  54  may include any desired transmission line structures. In one suitable arrangement that is sometimes described herein as an example, first transmission line  68  is a stripline embedded in dielectric substrate  58  and coupled to antenna  30 , whereas second transmission line  54  is a coaxial cable coupled to the millimeter/centimeter wave transceiver circuitry. First transmission line  68  may therefore sometimes be referred to herein as stripline  68  and second transmission line  54  may sometimes be referred to herein as coaxial cable  54 . 
     In general, coaxial cable  54  and radio-frequency connector  52  exhibit a first impedance at the frequency of operation of antenna module  50  whereas stripline  68  exhibits a second impedance at the frequency of operation. If care is not taken, impedance mismatches at the transition (interface) between coaxial cable  54  and stripline  68  can produce undesirable signal reflections that serve to minimize the overall antenna efficiency for antenna  30 . In some scenarios, impedance matching circuitry such as quarter wave transformers are mounted to dielectric substrate  58  and coupled to radio-frequency connector  52  to help match the impedance of coaxial cable  54  to the impedance of stripline  68 . However, in practice, quarter wave transformers can occupy an excessive amount of space on antenna module  50 , where space is often at a premium. In order to minimize space consumption on antenna module  50 , antenna module  50  may include millimeter and centimeter wave impedance matching structures  56  embedded within substrate  58 . Impedance matching structures  56  may include conductive traces and conductive vias embedded in dielectric substrate  58 . The conductive traces and conductive vias may define a volume of dielectric substrate  58  that is configured to match the impedance of coaxial cable  54  to the impedance of stripline  68  (e.g., impedance matching structures  56  may be configured to match the impedance of coaxial cable  54  to the impedance of stripline  68  without the need for additional discrete components such as quarter wave transformers). 
       FIG. 7  is a top-down view of a given radio-frequency connector  52  on antenna module  50  (e.g., as viewed in the direction of arrow  53  of  FIG. 6 ). In the example of  FIG. 7 , coaxial cable  54  of  FIG. 6  has been removed from radio-frequency connector  52  and the stripline embedded in antenna module  50  is not shown for the sake of clarity. 
     As shown in  FIG. 7 , radio-frequency connector  52  may be mounted to conductive traces  70  on top surface  60  of dielectric substrate  58 . Conductive traces  70  may be held at a ground potential and may therefore sometimes be referred to herein as ground traces  70 . Ground traces  70  may form part of the antenna ground for the antennas in antenna module  50  (e.g., ground traces  70  may form a part of antenna ground  46  of  FIG. 5 ). Radio-frequency connector  52  may have a conductive body (housing)  72 . Conductive body  72  may include an outer portion  72 G and an inner portion  72 S that is laterally surrounded by outer portion  72 G. Conductive body  72  extends upwards from ground traces  70  and away from dielectric substrate  58  (e.g., in the −Z direction of  FIG. 7 ). Conductive body  72  may exhibit rotational symmetry about central axis  75 . 
     Outer portion  72 G of conductive body  72  may be electrically and mechanically coupled to ground traces  70  using solder or other conductive interconnect structures (e.g., conductive adhesive, welds, etc.). This may serve to ground outer portion  72 G to the antenna ground for antenna module  50 . Outer portion  72 G may therefore sometimes be referred to herein as the grounded body portion  72 G of radio-frequency connector  52 . Conductive body  72  may have a cavity such as cavity  74  that extends from the top surface of radio-frequency connector  52  downwards towards dielectric substrate  58  (e.g., in +Z direction of  FIG. 7 ). Cavity  74  may overlap with an opening in ground traces  70 . A contact pad  76  may be formed from a conductive trace on surface  60  within the opening in ground traces  70 . Contact pad  76  may be coupled to the signal conductor of the stripline within antenna module  50  by conductive through vias extending vertically through dielectric substrate  58  (not shown in  FIG. 7  for the sake of clarity). Inner portion  72 S of conductive body  72  may be electrically and mechanically coupled to contact pad  76  (e.g., using solder, welds, conductive adhesive, etc.). 
     Cavity  74  may receive a coaxial cable (e.g., coaxial cable  54  of  FIG. 6 ). When the coaxial cable is mounted to radio-frequency connector  52 , the signal conductor for the coaxial cable may pass through cavity  74  and may contact inner portion  72 S of conductive body  72 . Inner portion  72 S of conductive body  72  may therefore sometimes be referred to herein as the signal body portion  72 S of radio-frequency connector  52 . The ground conductor of the coaxial cable may be coupled to grounded body portion  72 G of radio-frequency connector  52 . If desired, grounded body portion  72 G may include screw threads or other fastening structures that help to secure the coaxial cable to radio-frequency connector  52 . Impedance matching structures within antenna module  50  (e.g., impedance matching structures  56  of  FIG. 6 ) may be used to match the impedance of the coaxial cable and radio-frequency connector  52  to the impedance of the stripline embedded within antenna module  50 . 
       FIG. 8  is a cross-sectional side view of the impedance matching structures within antenna module  50  (e.g., as taken along line AA′ of  FIG. 7  and viewed in the direction of arrow  66  of  FIG. 6 ). As shown in  FIG. 8 , grounded body portion  72 G of radio-frequency connector  52  laterally surrounds signal body portion  72 S of radio-frequency connector  52 . Signal body portion  72 S and grounded body portion  72 G may each be formed from a conductive material such as metal. Ground traces  70  may define opening  94 . Contact pad  76  may be formed on surface  60  of dielectric substrate  58  within opening  94 . Signal body portion  72 S may be coupled to contact pad  76 . Grounded body portion  72 G may be coupled to ground traces  70  using solder  90  (e.g., the inner edges of grounded body portion  72 G may be soldered to ground traces  70  using solder  90 ). In this way, grounded body portion  72 G may be held at a ground potential. 
     Dielectric substrate  58  may include multiple stacked dielectric layers  64 . Conductive traces  106  may be formed on a first (e.g., lower-most) dielectric layer  64 . Conductive traces  100  and  104  may be formed on a second dielectric layer  64 . Conductive traces  108  may be formed on a third dielectric layer  64 . Conductive traces  108 ,  106 , and  104  may each be held at a ground potential (e.g., may form part of antenna ground  46  of  FIG. 5 ) and may therefore sometimes be referred to herein as embedded (internal) ground traces or simply as ground traces. Ground traces  70  and contact pad  76  may be formed on a fourth (e.g., upper-most) dielectric layer  64 . The second dielectric layer  64  may be interposed between the first and third dielectric layers  64 . The third dielectric layer  64  may be interposed between the second and fourth dielectric layers  64 . One or more than one dielectric layer  64  may separate conductive traces  100  and ground traces  104  from ground traces  106 . One or more dielectric layers  64  may separate conductive traces  100  and ground traces  104  from ground traces  108 . One or more dielectric layers  64  may separate ground traces  108  from ground traces  70 . More than one dielectric layer  64  may be layered under ground traces  106  if desired. The example of  FIG. 8  is merely illustrative. 
     Conductive vias  114  may extend vertically through dielectric substrate  58  to couple ground traces  106  to ground traces  108  (e.g., without shorting to conductive traces  100 ). Conductive vias  96  may extend vertically through dielectric substrate  58  to couple ground traces  70  to ground traces  108  and to couple ground traces  108  to ground traces  106 . Conductive vias  96  may also couple ground traces  104  to ground traces  108  and/or ground traces  106 . Landing pads such as landing pads  93  may be provided to support conductive vias  96  on dielectric layers  64 . If desired, other conductive vias may also be used to couple ground traces  108  and/or ground traces  106  to ground traces  104  (not shown in  FIG. 8  for the sake of clarity). Similarly, if desired, additional conductive vias may be used to couple ground traces  70  to ground traces  108  (not shown in  FIG. 8  for the sake of clarity). 
     Conductive via  98  may extend vertically through dielectric substrate  58  to couple contact pad  76  to conductive traces  100 . Conductive landing pads such as landing pads  92  may be provided to support conductive via  98  at the interfaces between dielectric layers  64  from contact pad  76  to conductive traces  100  (e.g., conductive via  98  may be coupled to landing pads  92  at the surface of each dielectric layer  64  between conductive traces  100  and contact pad  76 ). 
     Stripline  68  may be formed from conductive traces  100  and ground traces  108  and  106 . Conductive traces  100  may form the signal conductor for stripline  68  (e.g., part of signal path  40  for radio-frequency transmission line path  32  of  FIG. 4 ). Conductive traces  100  may therefore sometimes be referred to herein as signal traces  100 . The portion of ground traces  108  and  106  overlapping signal traces  100  may form the ground conductor for stripline  68  (e.g., part of ground path  42  for radio-frequency transmission line path  32  of  FIG. 4 ). Stripline  68  may extend from conductive via  98  to a corresponding antenna on antenna module  50  (e.g., antenna  30  of  FIG. 6 ). 
     Coaxial cable  54  may be inserted into cavity  74  of radio-frequency connector  52 , as shown by arrow  82 , until inner signal conductor  80  is placed in contact with signal body portion  72 S and outer ground conductor  78  is placed in contact with grounded body portion  72 G of radio-frequency connector  52 . This may serve to ground outer ground conductor  78  of coaxial cable  54  to ground traces  70 ,  108 , and  106  through grounded body portion  72 G of radio-frequency connector  52 . At the same time, inner signal conductor  80  is electrically coupled to stripline  68  through signal body portion  72 S, contact pad  76 , conductive via  98 , and landing pads  92 . In other words, signal traces  100 , conductive via  98 , landing pads  92 , signal body portion  72 S of radio-frequency connector  52 , and inner signal conductor  80  of coaxial cable  54  may each form part of signal path  40  for radio-frequency transmission line path  32  of  FIG. 4 . Similarly, outer ground conductor  78 , grounded body portion  72 G, conductive vias  96 , landing pads  93 , conductive vias  114 , ground traces  108 , and ground traces  106  may each form part of ground path  42  for radio-frequency transmission line path  32  of  FIG. 4 . Radio-frequency signals may subsequently be conveyed over coaxial cable  54 , radio-frequency connector  52 , conductive vias  98  and  96 , and stripline  68 . 
     As shown in  FIG. 8 , impedance matching structures  56  may be embedded within dielectric substrate  58 . Impedance matching structures  56  may include landing pads  92 , landing pads  93 , conductive vias  96 , contact pad  76 , ground traces  106 , and the volume (cavity)  99  between these components. Volume  99  may have dimensions defined by landing pads  92 , landing pads  93 , and conductive vias  96 . For example, volume  99  may be defined by the width  110  of landing pads  92  and a diameter  112  between opposing conductive vias  96 . 
     Impedance matching structures  56  may serve as an interface between stripline  68  and radio-frequency connector  52 /coaxial cable  54 . Impedance matching structures  56  may serve to match the impedance of coaxial cable  54  and radio-frequency connector  52  (e.g., 50 Ohms) to the impedance of stripline  68 . For example, the dimensions of volume  99  (e.g., the ratio of diameter  112  to width  110 ) may be selected, for the dielectric constant d k  of dielectric substrate  58  within volume  99 , to match the impedance of stripline  68  to the impedance of radio-frequency connector  52  and coaxial cable  54  over the frequency band covered by antenna module  50 . In other words, impedance matching structures  56  may insure that an impedance of 50 Ohms is maintained from coaxial cable  54 , through radio-frequency connector  52 , the transition between radio-frequency connector  52  and stripline  68 , and stripline  68  over the frequency band covered by antenna module  50 . This may serve to minimize reflection and loss of radio-frequency signals at the interface between stripline  68  and coaxial cable  54 . When arranged in this way, impedance matching structures  56  may provide impedance matching over a relatively wide bandwidth (e.g., from 20 GHz to 50 GHz, from 10 GHz to 60 GHz, from 10 GHz to 70 GHz, etc.). By embedding impedance matching structures  56  within the stack-up of antenna module  50 , bulky quarter wave transformers or other surface mounted impedance matching components may be omitted from antenna module  50 . 
     Ground traces  104  may be separated from signal traces  100  by gap  102 . If desired, ground traces  104  may laterally surround signal traces  100  (e.g., in the X-Y plane of  FIG. 8 ). Ground traces  104  may serve to shield signal traces  100  from electromagnetic interference and may allow multiple striplines for different radio-frequency transmission line paths to be formed from signal traces on the same dielectric layer  64  with sufficient electromagnetic isolation between each of the radio-frequency transmission line paths. 
     If desired, outer ground conductor  78  of coaxial cable  54  may be secured to grounded body portion  72 G of radio-frequency connector  52  using conductive adhesive, solder, welds, screw threads on coaxial cable  54  and cavity  74 , or using any other desired conductive interconnect structures. Similarly, if desired, inner signal conductor  80  may be soldered, welded, or adhered to signal body portion  72 S of radio-frequency connector  52 . This is merely illustrative. In one suitable arrangement, outer ground conductor  78  and cavity  74  both include screw threads that allow coaxial cable  54  to be screwed onto radio-frequency connector  52  and inner signal conductor  80  is placed into contact with signal body portion  72 S without solder. This may allow coaxial cable  54  to be easily removed from radio-frequency connector  52  as needed. 
     The example of  FIG. 8  is merely illustrative. In another suitable arrangement, ground traces  108  may be omitted and ground traces  70  may be used to form part of the ground conductor for stripline  68 .  FIG. 9  is a cross-sectional side view of antenna module  50  in a scenario where ground traces  108  are omitted. 
     As shown in  FIG. 9 , ground traces  70  may form part of the ground conductor for stripline  68 . Conductive vias  114  may couple ground traces  70  to ground traces  106 . Volume  99  between conductive vias  96 , contact pad  76 , and ground traces  106  may configure impedance matching structures  56  to match the impedance of stripline  68  to the impedance of radio-frequency connector  52  and the coaxial cable over the frequency band of operation of antenna module  50 . The example of  FIG. 9  in which conductive via  98  extends through a single dielectric layer  64  is merely illustrative. If desired, conductive via  98  may extend through two or more dielectric layers  64  (e.g., two or more dielectric layers may be interposed between ground traces  70  and signal traces  100 ). Landing pads (e.g., landing pads  92  of  FIG. 8 ) may be provided at the interface between each dielectric layer to support conductive via  98 . The landing pads may help to define the dimensions of volume  99  to configure impedance matching structures  56  to match the impedance of stripline  68  to the impedance of radio-frequency connector  52  and the coaxial cable. 
       FIG. 10  is a top-down view of opening  94  in ground traces  70  in the absence of radio-frequency connector  52 . As shown in  FIG. 10 , contact pad  76  may be located within opening  94  in ground traces  70 . The end of signal traces  100  overlap contact pad  76  (e.g., signal traces  100  are coupled to contact pad  76  by conductive via  98  of  FIGS. 8 and 9 ). A ring-shaped fence of conductive vias  96  may extend from ground traces  70  to ground traces  106  ( FIGS. 8 and 9 ) through dielectric substrate  58 . The fence of conductive vias  96  may extend around opening  94  and may define the diameter  112  of volume  99  in impedance matching structures  56 . The landing pads for conductive vias  96  (e.g., landing pads  93  of  FIG. 8 ) may also help to define diameter  112 . Contact pad  76  may have width  110  if desired. Width  110 , diameter  112 , and the dielectric constant of the material in dielectric substrate  58  within volume  99  may be selected to configure impedance matching structures  56  to match the impedance of stripline  68  to the impedance of the radio-frequency connector and the coaxial cable over the frequency band covered by antenna module  50 . 
     Fences of conductive vias  114  may surround signal traces  100  in stripline  68 . Stripline  68  may have a width (e.g., a width measured from one fence of conductive vias  114  on one side of signal traces  100  to the other fence of conductive vias  114  on the other side of signal traces  100 ) that is less than diameter  112 . 
     Conductive vias  114  may be separated from one or more adjacent conductive vias  114  and conductive vias  96  may be separated from one or more adjacent conductive vias  96  by a distance that is sufficiently small so as to be opaque at the wavelengths of operation of antenna module  50 . For example, conductive vias  114  may be separated from one or more adjacent conductive vias  114  and conductive vias  96  may be separated from one or more adjacent conductive vias  96  by less than one-sixth of the lowest effective wavelength of operation of antenna module  50 , less than one-tenth the lowest effective wavelength, less than one-fifteenth the lowest effective wavelength, etc. 
       FIG. 11  is a plot illustrating the radio-frequency performance of impedance matching structures  56 . As shown in  FIG. 11 , curve  116  plots the reflection coefficient S 11  of the radio-frequency transmission line path for antenna module  50  (e.g., radio-frequency transmission line path  32  of  FIG. 4 ) at the interface between radio-frequency connector  52  and stripline  68  (e.g., at the location of impedance matching structures  56 ). As shown by curve  116 , the radio-frequency transmission line path exhibits minimal signal reflection (and thus provides a maximum efficiency for the antenna coupled to the radio-frequency transmission line path) at frequency F 1 . The radio-frequency transmission line path may exhibit an acceptably low reflection coefficient (e.g., a reflection coefficient below threshold value TH) across a corresponding bandwidth BW. Impedance matching structures  56  (e.g., the dimensions of volume  99  and the material within volume  99 ) may be selected to align bandwidth BW with the frequency band of operation for antenna module  50 . In this way, impedance matching structures  56  may ensure that minimal signal reflection occurs at the transition between coaxial cable  54  and stripline  68 , thereby maximizing antenna efficiency for the antenna coupled to the stripline. 
     The example of  FIGS. 8-10  is merely illustrative. Volume  99  may have any desired shape (e.g., shapes having curved and/or straight sides). Radio-frequency connector  52  may have any desired shape. Stripline  68  may be replaced with any desired type of transmission line such as a microstrip transmission line, an edge-coupled microstrip transmission line, an edge-coupled stripline transmission line, a waveguide structure, etc. Coaxial cable  54  may be replaced with any desired type of transmission line. 
     In the example of  FIGS. 4-11 , radio-frequency connector  52  and impedance matching structures  56  are used during operation of device  10  by an end user. In another suitable arrangement, radio-frequency connector  52  and impedance matching structures  56  may be used for performing radio-frequency testing of antenna  30  during design, manufacturing, and/or assembly of device  10 . For example, antenna modules  50  may be assembled in a manufacturing system. Antenna modules  50  may be assembled to include an antenna  30  and impedance matching structures  56  in the manufacturing system. Radio-frequency connectors  52  may be mounted to antenna modules  50  in the manufacturing system. Coaxial cables (e.g., coaxial cables  54  of  FIG. 6 ) may be coupled to the radio-frequency connectors. Radio-frequency test equipment may be coupled to the coaxial cables and may convey radio-frequency test signals over the antenna module (e.g., over the coaxial cables and the radio-frequency connectors). The test equipment may gather test data from the radio-frequency test signals to test the radio-frequency performance of the antennas in the antenna modules. If the test data indicates that the antennas exhibit satisfactory performance, the antennas may subsequently be assembled into electronic device  10  ( FIG. 1 ) or may be used to assemble additional antenna modules (e.g., antenna modules having antennas of the same design). If the test data indicates that the antenna exhibits unsatisfactory performance, the antenna may be scrapped, reworked, or redesigned. Impedance matching structures  56  may ensure that minimal signal reflection occurs during this test and validation operation and to ensure that accurate test data is gathered, for example. 
     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: 20190515
Publication Date: 20220329
Grant Date: 20220329
Priority Date: 20190408
Inventors: PAULOTTO, Simone
EDWARDS, JENNIFER M.
RAJAGOPALAN, HARISH
AVSER, BILGEHAN
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K1/113", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09609", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01P5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01P1/045", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01P5/085", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09809", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0222", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/09809", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0221", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/6473", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10189", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01P5/085", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0251", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01P1/022", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09454", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10098", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/09609", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10189", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0251", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/09227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/6473", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10189", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/09609", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/113", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01P5/085", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09809", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0251", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 72661955