PATENT DOCUMENT

Publication Number: US-11070300-B2
Application Number: US-201916357184-A
Country: US
Kind Code: B2

Title: Test probes for phased antenna arrays

Abstract:
An electronic device may be provided with wireless circuitry that is tested in a test system. The test system may include test probes. Circuitry under test may wirelessly transmit test signals. The test probes may receive the test signals at multiple locations. Circuitry may measure direct current (DC) voltages generated by the test probes and may convert the voltages to electric field magnitudes. A test host may process the electric field magnitudes to determine whether the circuitry under test exhibits a satisfactory radiation pattern. The test probes may include dielectric substrates and one or more dipole elements coupled to respective diodes. The dipole elements may include indium tin oxide (ITO) and may include first and second sets of orthogonal dipole elements. Transmission lines coupled to the dipole elements may include ITO and may form low pass filters that convert rectified voltages produced by the diodes into the DC voltages.

Claims:
What is claimed is: 
     
       1. Apparatus comprising:
 a dielectric substrate; 
 contact pads on the dielectric substrate; 
 a transmission line on the dielectric substrate and coupled to the contact pads; 
 a dipole element on the dielectric substrate and having first and second arms and coupled to the transmission line; 
 a diode coupled between the first and second arms of the dipole element, wherein the diode is configured to generate a rectified voltage based on a current on the dipole element, the current having a frequency greater than 10 GHz, and the transmission line is configured to filter the rectified voltage to produce a direct current (DC) voltage; and 
 circuitry coupled to the contact pads, and configured to compute a first electric field magnitude value based on the rectified voltage and to interpolate a second electric field magnitude value based on an additional rectified voltage gathered by the circuitry, the first electric field magnitude value being associated with a first component of an electric field that produced the current, and the second electric field magnitude value being associated with a second component of the electric field that is orthogonal to the first component. 
 
     
     
       2. The apparatus defined in  claim 1 , wherein the dielectric substrate comprises glass. 
     
     
       3. The apparatus defined in  claim 2 , wherein the first and second arms of the dipole element comprise indium tin oxide traces patterned on the glass and metal on the indium tin oxide traces. 
     
     
       4. The apparatus defined in  claim 1 , wherein the transmission line comprises indium tin oxide traces and is configured to form a low pass filter that generates the DC voltage based on the rectified voltage. 
     
     
       5. The apparatus defined in  claim 4 , wherein the transmission line comprises a first conductive line coupled to the first arm of the dipole element and a second conductive line coupled to the second arm of the dipole element, the first conductive line is separated from the second conductive line by less than 50 microns, and the transmission line has a length greater than five centimeters. 
     
     
       6. The apparatus defined in  claim 1 , wherein the circuitry comprises:
 test measurement circuitry coupled to the contact pads, the test measurement circuitry being configured to sense the DC voltage and having circuitry selected from the group consisting of: an analog-to-digital converter and a voltmeter. 
 
     
     
       7. The apparatus defined in  claim 1 , further comprising:
 additional contact pads on the dielectric substrate; 
 an additional transmission line on the dielectric substrate and coupled to the additional contact pads; 
 an additional dipole element having third and fourth arms coupled to the additional transmission line, wherein the third and fourth arms of the additional dipole element are perpendicular to the first and second arms of the dipole element; and 
 an additional diode coupled between the third and fourth arms of the additional dipole element. 
 
     
     
       8. The apparatus defined in  claim 7 , wherein the dipole element and the additional dipole element are part of an M-by-N array of dipole elements on a lateral surface of the dielectric substrate, M and N each being greater than or equal to two. 
     
     
       9. The apparatus defined in  claim 7 , wherein the dielectric substrate has a first surface and a second surface perpendicular to the first surface, the dipole element being formed on the first surface and the additional dipole element being formed on the second surface. 
     
     
       10. A radio-frequency test probe configured to receive radio-frequency signals transmitted by circuitry under test, the radio-frequency test probe comprising:
 a dielectric substrate having a lateral surface; 
 an array of dipole elements on the lateral surface; 
 transmission lines on the lateral surface and coupled to the dipole elements in the array; 
 diodes coupled to the dipole elements in the array, wherein the diodes are configured to produce, on the transmission lines, rectified voltages corresponding to the received radio-frequency signals; and 
 circuitry coupled to the transmission lines, mounted to the dielectric substrate, configured to measure the rectified voltages generated by the diodes, and configured to compute corresponding electric field magnitude values using the measured rectified voltages. 
 
     
     
       11. The radio-frequency test probe defined in  claim 10 , wherein the array of dipole elements comprises a first set of dipole elements and a second set of dipole elements oriented perpendicular to the dipole elements in the first set, each dipole element in the first and second sets being coupled to a respective one of the diodes. 
     
     
       12. The radio-frequency test probe defined in  claim 10  wherein the dielectric substrate comprises glass and the dipole elements comprise indium tin oxide patterned on the glass. 
     
     
       13. The radio-frequency test probe defined in  claim 10 , further comprising:
 a dielectric layer on the dielectric substrate, wherein the dielectric substrate is interposed between the array of dipole elements and the dielectric layer, the dielectric layer having a thickness that configures the dielectric layer to mitigate reflected electromagnetic energy at the array of dipole elements. 
 
     
     
       14. The radio-frequency test probe defined in  claim 10 , further comprising:
 an absorber layer on the lateral surface of the dielectric substrate, wherein the array of dipole elements is configured to receive the radio-frequency signals through the absorber layer. 
 
     
     
       15. Wireless test equipment configured to perform radio-frequency testing on circuitry under test, the wireless test equipment comprising:
 a fixture configured to receive the circuitry under test; 
 a radio-frequency test probe comprising:
 a dielectric substrate having a first surface and a second surface perpendicular to the first surface, 
 contact pads on the first surface, 
 a transmission line on the first surface and coupled to the contact pads, 
 a dipole element on the first surface and coupled to the transmission line, wherein the dipole element is located at an edge of the first surface defined by the second surface, and 
 a diode coupled to the dipole element; 
 
 a mechanical positioner configured to hold the radio-frequency test probe at a fixed distance from the fixture while the second surface faces the fixture; and 
 measurement circuitry coupled to the contact pads and configured to measure a voltage across the contact pads. 
 
     
     
       16. The wireless test equipment defined in  claim 15 , wherein the dielectric substrate has a third surface perpendicular to the first and second surfaces and the radio-frequency test probe further comprises:
 additional contact pads on the third surface; 
 an additional transmission line on the third surface and coupled to the additional contact pads; 
 an additional dipole element on the third surface and coupled to the additional transmission line, wherein the additional dipole element is located at an edge of the third surface that is defined by the second surface; and 
 an additional diode coupled to the additional dipole element, wherein the measurement circuitry is coupled to the additional contact pads and is configured to measure an additional voltage across the additional contact pads. 
 
     
     
       17. The wireless test equipment defined in  claim 15 , further comprising an array of radio-frequency test probes, wherein the array of radio-frequency test probes comprises:
 a printed circuit board; and 
 an insulator member on the printed circuit board, wherein the radio-frequency test probe is embedded within the insulator member and the insulator member separates the radio-frequency test probe from at least one additional radio-frequency test probe in the array of radio-frequency test probes. 
 
     
     
       18. The wireless test equipment defined in  claim 15 , further comprising an additional radio-frequency test probe that comprises:
 an additional dielectric substrate having a third surface and a fourth surface perpendicular to the third surface, wherein the third surface extends perpendicular to the first surface of the dielectric substrate, and the fourth surface is coplanar with the second surface of the dielectric substrate; 
 additional contact pads on the third surface; 
 an additional transmission line on the third surface and coupled to the additional contact pads; 
 an additional dipole element on the third surface and coupled to the additional transmission line, wherein the additional dipole element is located at an edge of the third surface defined by the fourth surface; and 
 an additional diode coupled to the additional dipole element.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless circuitry. 
     Electronic devices often include wireless 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, radio-frequency communications in millimeter and centimeter wave communications bands can be characterized by substantial attenuation and/or distortion during signal propagation through various mediums. 
     Wireless test equipment is often used to ensure that wireless circuitry for handling millimeter and centimeter wave communications is operating properly. If care is not taken, wireless test equipment for testing wireless circuitry of this type can be unreliable and prohibitively expensive to assemble and operate. 
     It would therefore be desirable to be able to provide improved wireless test equipment for testing wireless circuitry that handles millimeter and centimeter wave communications. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry. The wireless circuitry may include a phased antenna array that conveys radio-frequency signals in one or more frequency bands between 10 GHz and 300 GHz. The radio-frequency performance of the phased antenna array and other portions of the wireless circuitry may be tested in a wireless test system. The wireless test system may include test equipment such as a test fixture, test measurement circuitry, and one or more test probes. The test measurement circuitry may include an analog-to-digital converter, a voltmeter, and/or other circuitry. A test host may be coupled to the test equipment. The test system may perform radio-frequency test operations on circuitry under test while the circuitry under test is received by the test fixture. The circuitry under test may include some or all of the phased antenna array and/or other portions of the wireless circuitry for the electronic device. 
     During the radio-frequency test operations, the test host may control the circuitry under test to transmit radio-frequency test signals (e.g., at a frequency greater than 10 GHz). The test probes may receive the radio-frequency test signals at multiple locations across the field of view of the phased antenna array in the circuitry under test. The test measurement circuitry may measure voltages generated by the test probes and may convert the measured voltages to electric field magnitude values. The test probes may receive the radio-frequency test signals at multiple distances from the circuitry under test to determine phases of the radio-frequency test signals. The test host may process the electric field magnitude values and/or the phases of the radio-frequency test signals to determine whether the phased antenna array in the circuitry under test exhibits a satisfactory radiation pattern (e.g., a sufficiently uniform radiation pattern envelope). 
     The test probe may include a dielectric substrate such as a glass substrate and one or more dipole elements on the dielectric substrate. The dipole elements may be formed from indium tin oxide or other conductive traces patterned on the dielectric substrate. The dipole elements may each have first and second dipole arms and a respective diode coupled between the first and second dipole arms. Contact pads may be formed on the dielectric substrate. Transmission lines may couple the dipole elements to respective pairs of the contact pads. The radio-frequency test signals may produce radio-frequency currents on the dipole arms and the diodes may generate rectified voltages from the radio-frequency currents. The transmission lines may serve as low pass filters that block radio-frequency signals from passing to the contact pads and that convert the rectified voltages into direct current (DC) voltages (e.g., in scenarios where the transmission lines are formed using indium tin oxide). The test measurement circuitry may sense the DC voltages across the contact pads. 
     In one suitable arrangement, the test probe may be a planar test probe having an M-by-N array of dipole elements on a lateral surface of the dielectric substrate. The array may include a first set of dipole elements and a second set of dipole elements oriented perpendicular to the dipole elements in the first set. In another suitable arrangement, the test probe may be a vertical test probe having a dipole element located at a bottom edge of the dielectric substrate. If desired, the vertical test probe may include orthogonal dipole elements located on orthogonal surfaces of the dielectric substrate. Use of orthogonal dipole elements in the test probe may allow the test probe to generate DC voltages from orthogonal electric field components of the radio-frequency test signals. The test host may interpolate electric field magnitude values for each electric field component at the location of each dipole element in the test probe. The test probe may be relatively inexpensive to assemble and operate and may perform reliable radio-frequency testing on the circuitry under test. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of illustrative circuitry in an electronic device in accordance with some embodiments. 
         FIG. 2  is a schematic diagram of illustrative wireless circuitry in an electronic device in accordance with some embodiments. 
         FIG. 3  is a diagram of an illustrative phased antenna array in an electronic device in accordance with some embodiments. 
         FIG. 4  is a diagram of an illustrative wireless test system for performing radio-frequency test operations on wireless circuitry under test in accordance with some embodiments. 
         FIG. 5  is a diagram of an illustrative test probe that may be used to perform radio-frequency test operations on wireless circuitry under test in accordance with some embodiments. 
         FIG. 6  is a flow chart of illustrative steps involved with performing radio-frequency test operations on wireless circuitry under test in accordance with some embodiments. 
         FIG. 7  is a bottom-up view of an illustrative planar test probe having an array of dipole elements for measuring the radiation pattern of wireless circuitry under test in accordance with some embodiments. 
         FIG. 8  is a side view showing how an illustrative planar test probe may be placed over wireless circuitry under test for measuring the radiation pattern of the wireless circuitry under test in accordance with some embodiments. 
         FIG. 9  is a flow chart of illustrative steps involved with performing radio-frequency test operations on wireless circuitry under test using a planar test probe in accordance with some embodiments. 
         FIG. 10  is a side view of an illustrative vertical test probe having a dipole element for measuring the radiation pattern of wireless circuitry under test in accordance with some embodiments. 
         FIG. 11  is a perspective view of an illustrative vertical test probe having multiple dipole elements for measuring orthogonal electric field components of the radiation pattern of wireless circuitry under test in accordance with some embodiments. 
         FIG. 12  is a side view of illustrative wireless equipment for measuring the radiation pattern of wireless circuitry under test using a vertical test probe of the types shown in  FIGS. 10 and 11  in accordance with some embodiments. 
         FIG. 13  is a cross-sectional side view of an illustrative vertical test probe array that may be used to measure the radiation pattern of wireless circuitry under test in accordance with some embodiments. 
         FIG. 14  is a bottom-up view of an illustrative vertical test probe array that may be used to measure orthogonal electric field components of the radiation pattern of wireless circuitry under test in accordance with some embodiments. 
         FIG. 15  is a side view of an illustrative planar test probe having an array of dipole elements and multiple layers of dielectric material for mitigating the effects of reflected radio-frequency signals at the dipole elements in accordance with some embodiments. 
         FIG. 16  is a side view of an illustrative planar test probe having an absorber layer under an array of dipole elements for mitigating the effect of reflected radio-frequency signals at the dipole elements in accordance with some embodiments. 
         FIG. 17  is a side view showing how multiple planar test probes may be used to concurrently measure the radiation pattern of wireless circuitry under test in accordance with some embodiments. 
         FIG. 18  is a cross-sectional side view showing how a dipole element for a test probe may be formed on an underlying substrate in accordance with some embodiments. 
         FIG. 19  is a top-down view showing how a dipole element for a test probe may be formed on an underlying substrate in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     A schematic diagram showing illustrative components that may be used in an electronic device such as electronic device  10  is shown in  FIG. 1 . Electronic devices such as electronic device  10  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 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 portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, a wireless access point, a wireless base station, an electronic device incorporated into a kiosk, building, or vehicle, or other suitable electronic equipment. 
     As shown in  FIG. 1 , device  10  may include a housing such as housing  22 . Housing  22  may be formed using a unibody configuration in which some or all of housing  22  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.). Antennas may be mounted along the peripheral edges of housing  22 , on a rear of housing  22 , under a dielectric window in a conductive portion of housing  22 , or at any other desired location in device  10 . 
     Device  10  may include control circuitry  28 . Control circuitry  28  may include storage such as storage circuitry  30 . Storage circuitry  30  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  28  may include processing circuitry such as processing circuitry  32 . Processing circuitry  32  may be used to control the operation of device  10 . Processing circuitry  32  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  28  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  30  (e.g., storage circuitry  30  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  30  may be executed by processing circuitry  32 . 
     Control circuitry  28  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  28  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless 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  24 . Input-output circuitry  24  may include input-output devices  26 . Input-output devices  26  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  26  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  24  may include wireless circuitry such as wireless circuitry  34  for wirelessly conveying radio-frequency signals. While control circuitry  28  is shown separately from wireless circuitry  34  in the example of  FIG. 2  for the sake of clarity, wireless circuitry  34  may include processing circuitry that forms a part of processing circuitry  32  and/or storage circuitry that forms a part of storage circuitry  30  of control circuitry  28  (e.g., portions of control circuitry  28  may be implemented on wireless circuitry  34 ). As an example, control circuitry  28  may include baseband processor circuitry or other control components that form a part of wireless circuitry  34 . 
     Wireless circuitry  34  may include millimeter and centimeter wave transceiver circuitry such as millimeter/centimeter wave transceiver circuitry  38 . Millimeter/centimeter wave transceiver circuitry  38  may support communications at frequencies between about 10 GHz and 300 GHz. For example, millimeter/centimeter wave transceiver circuitry  38  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  38  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  38  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  38  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.). 
     If desired, millimeter/centimeter wave transceiver circuitry  38  (sometimes referred to herein simply as transceiver circuitry  38  or millimeter/centimeter wave circuitry  38 ) may perform spatial ranging operations using radio-frequency signals at millimeter and/or centimeter wave signals that are transmitted and received by millimeter/centimeter wave transceiver circuitry  38 . 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  28  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  28  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  38  are unidirectional. Millimeter/centimeter wave transceiver circuitry  38  may perform bidirectional communications with external wireless equipment. Bidirectional communications involve both the transmission of wireless data by millimeter/centimeter wave transceiver circuitry  38  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  34  may include transceiver circuitry for handling communications at frequencies below 10 GHz such as non-millimeter/centimeter wave transceiver circuitry  36 . Non-millimeter/centimeter wave transceiver circuitry  36  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  36  and millimeter/centimeter wave transceiver circuitry  38  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  34  may include antennas  40 . Non-millimeter/centimeter wave transceiver circuitry  36  may transmit and receive radio-frequency signals below 10 GHz using one or more antennas  40 . Millimeter/centimeter wave transceiver circuitry  38  may transmit and receive radio-frequency signals above 10 GHz (e.g., at millimeter wave and/or centimeter wave frequencies) using antennas  40 . 
     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  38  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  40  in wireless circuitry  34  may be formed using any suitable antenna types. For example, antennas  40  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. In another suitable arrangement, antennas  40  may include antennas with dielectric resonating elements such as dielectric resonator antennas. If desired, one or more of antennas  40  may be cavity-backed antennas. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a non-millimeter/centimeter wave wireless link for non-millimeter/centimeter wave transceiver circuitry  36  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  38 . Antennas  40  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  40  that may be formed in a phased antenna array for conveying radio-frequency signals at millimeter and centimeter wave frequencies is shown in  FIG. 2 . As shown in  FIG. 2 , antenna  40  may be coupled to millimeter/centimeter (MM/CM) wave transceiver circuitry  38 . Millimeter/centimeter wave transceiver circuitry  38  may be coupled to antenna feed  44  of antenna  40  using a transmission line path that includes radio-frequency transmission line  42 . Radio-frequency transmission line  42  may include a positive signal conductor such as signal conductor  46  and may include a ground conductor such as ground conductor  48 . Ground conductor  48  may be coupled to the antenna ground for antenna  40  (e.g., over a ground antenna feed terminal of antenna feed  44  located on the antenna ground). Signal conductor  46  may be coupled to the antenna resonating element for antenna  40 . For example, signal conductor  46  may be coupled to a positive antenna feed terminal of antenna feed  44  located on the antenna resonating element. In another suitable arrangement, antenna  40  may be indirectly fed. For example, signal conductor  46  may indirectly feed radio-frequency signals to a portion of antenna  40  via near-field electromagnetic coupling and the antenna resonating element for antenna  40  may radiate the indirectly-fed radio-frequency signals. 
     Radio-frequency transmission line  42  may include a stripline transmission line (sometimes referred to herein simply as a stripline), a coaxial cable, a coaxial probe realized by metalized vias, a microstrip transmission line, an edge-coupled microstrip transmission line, an edge-coupled stripline transmission lines, a waveguide structure, combinations of these, etc. Multiple types of transmission lines may be used to form the transmission line path that couples millimeter/centimeter wave transceiver circuitry  38  to antenna feed  44 . Filter circuitry, switching circuitry, impedance matching circuitry, phase shifter circuitry, amplifier circuitry, and/or other circuitry may be interposed on radio-frequency transmission line  42 , 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). 
       FIG. 3  shows how antennas  40  for handling radio-frequency signals at millimeter and centimeter wave frequencies may be formed in a phased antenna array. As shown in  FIG. 3 , phased antenna array  54  (sometimes referred to herein as array  54 , antenna array  54 , or array  54  of antennas  40 ) may be coupled to radio-frequency transmission lines  42 . For example, a first antenna  40 - 1  in phased antenna array  54  may be coupled to a first radio-frequency transmission line  42 - 1 , a second antenna  40 - 2  in phased antenna array  54  may be coupled to a second radio-frequency transmission line  42 - 2 , an Nth antenna  40 -N in phased antenna array  54  may be coupled to an Nth radio-frequency transmission line  42 -N, etc. While antennas  40  are described herein as forming a phased antenna array, the antennas  40  in phased antenna array  54  may sometimes also be referred to as collectively forming a single phased array antenna. 
     Antennas  40  in phased antenna array  54  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 lines  42  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  38  ( FIG. 2 ) to phased antenna array  54  for wireless transmission. During signal reception operations, radio-frequency transmission lines  42  may be used to convey signals received at phased antenna array  54  (e.g., from external wireless equipment or transmitted signals that have been reflected off of external objects) to millimeter/centimeter wave transceiver circuitry  38  ( FIG. 2 ). 
     The use of multiple antennas  40  in phased antenna array  54  allows 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. 3 , antennas  40  each have a corresponding radio-frequency phase and magnitude controller  50  (e.g., a first phase and magnitude controller  50 - 1  interposed on radio-frequency transmission line  42 - 1  may control phase and magnitude for radio-frequency signals handled by antenna  40 - 1 , a second phase and magnitude controller  50 - 2  interposed on radio-frequency transmission line  42 - 2  may control phase and magnitude for radio-frequency signals handled by antenna  40 - 2 , an Nth phase and magnitude controller  50 -N interposed on radio-frequency transmission line  42 -N may control phase and magnitude for radio-frequency signals handled by antenna  40 -N, etc.). 
     Phase and magnitude controllers  50  may each include circuitry for adjusting the phase of the radio-frequency signals on radio-frequency transmission lines  42  (e.g., phase shifter circuits) and/or circuitry for adjusting the magnitude of the radio-frequency signals on radio-frequency transmission lines  42  (e.g., power amplifier and/or low noise amplifier circuits). Phase and magnitude controllers  50  may sometimes be referred to collectively herein as beam steering circuitry (e.g., beam steering circuitry that steers the beam of radio-frequency signals transmitted and/or received by phased antenna array  54 ). 
     Phase and magnitude controllers  50  may adjust the relative phases and/or magnitudes of the transmitted signals that are provided to each of the antennas in phased antenna array  54  and may adjust the relative phases and/or magnitudes of the received signals that are received by phased antenna array  54 . Phase and magnitude controllers  50  may, if desired, include phase detection circuitry for detecting the phases of the received signals that are received by phased antenna array  54 . The term “beam” or “signal beam” may be used herein to collectively refer to wireless signals that are transmitted and received by phased antenna array  54  in a particular direction. The signal beam may exhibit a peak gain that is oriented in a particular pointing direction at a corresponding 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  50  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. 3  that is oriented in the direction of point A. If, however, phase and magnitude controllers  50  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  50  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  50  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  50  may be controlled to produce a desired phase and/or magnitude based on a corresponding control signal  52  received from control circuitry  28  of  FIG. 1  (e.g., the phase and/or magnitude provided by phase and magnitude controller  50 - 1  may be controlled using control signal  52 - 1 , the phase and/or magnitude provided by phase and magnitude controller  50 - 2  may be controlled using control signal  52 - 2 , etc.). If desired, the control circuitry may actively adjust control signals  52  in real time to steer the transmit or receive beam in different desired directions over time. Phase and magnitude controllers  50  may provide information identifying the phase of received signals to control circuitry  28  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  54  and external communications equipment. If the external object is located at point A of  FIG. 3 , phase and magnitude controllers  50  may be adjusted to steer the signal beam towards point A (e.g., to steer the pointing direction of the signal beam towards point A). Phased antenna array  54  may transmit and receive radio-frequency signals in the direction of point A. Similarly, if the external communications equipment is located at point B, phase and magnitude controllers  50  may be adjusted to steer the signal beam towards point B (e.g., to steer the pointing direction of the signal beam towards point B). Phased antenna array  54  may transmit and receive radio-frequency signals in the direction of point B. In the example of  FIG. 3 , 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. 3 ). 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. 3 ). Phased antenna array  54  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. 
     Portions of the wireless circuitry in the device (e.g., wireless circuitry  34  of  FIG. 1 ) may be tested in a wireless test system to ensure that the wireless circuitry is operating properly. The wireless test system may include wireless test equipment. The wireless test equipment may, for example, perform radio-frequency test operations on portions of wireless circuitry  34  before wireless circuitry  34  is fully assembled and/or before wireless circuitry  34  is assembled into device  10 . The portions of wireless circuitry  34  that are tested using the wireless test equipment may sometimes be referred to herein as wireless circuitry under test or, more simply, as circuitry under test (CUT). The CUT may include some or all of antennas  40 , portions of one or more of antennas  40 , some or all of millimeter/centimeter wave transceiver circuitry  38 , portions of non-millimeter/centimeter wave transceiver circuitry  36 , other portions of wireless circuitry  34 , and/or portions of control circuitry  28  of  FIG. 1 . In one suitable arrangement that is sometimes described herein as an example, the circuitry under test includes at least phased antenna array  54  of  FIG. 3 . 
       FIG. 4  shows an illustrative wireless test system that may be used to perform radio-frequency test operations on circuitry under test. As shown in  FIG. 4 , a wireless test system such as test system  56  may include wireless test equipment such as test equipment  58  and a test host such as test host  62 . Test host  62  may be coupled to test equipment  58  over data path  64 . Data path  64  may include one or more control lines, a data bus, or any other lines for conveying control signals and test data between test host  62  and test equipment  58 . 
     Test host  62  may include computing equipment such as a personal computer, laptop computer, handheld or portable computer, or any other desired computing equipment. Test host  62  may be formed separate from (e.g., external to) test equipment  58 . In another suitable arrangement, test host  62  and test equipment  58  may be combined into a single testing device. 
     Test equipment  58  may include test fixture  66 , test measurement circuitry  70 , and one or more test probes  68 . Test equipment  58  may receive circuitry under test (CUT)  60 . Test equipment  58  may perform radio-frequency test operations on CUT  60 . For example, CUT  60  may be mounted to test fixture  66 . Test host  62  may control CUT  60  in test fixture  66  to transmit and/or receive radio-frequency test signals (e.g., radio-frequency test signals at millimeter and/or centimeter wave frequencies). Test measurement circuitry  70  may gather measurements (sometimes referred to herein as radio-frequency test data or test data) from the radio-frequency signals transmitted by CUT  60  using test probes  68 . Test measurement circuitry  70  may convey the test data to test host  62  over data path  64 . Test host  62  may analyze the test data to determine whether CUT  60  exhibits satisfactory radio-frequency performance. 
     The test data may include test data associated with any desired wireless performance metrics for CUT  60  (e.g., error rate data, noise data, signal to noise ratio data, received or transmitted power level data, etc.). In one suitable arrangement that is sometimes described herein as an example, the test data may include measurements of the radiation pattern of CUT  60 . The measurements of the radiation pattern of CUT  60  may include electric field magnitude and/or phase information associated with the radio-frequency test signals transmitted by CUT  60 . Test host  62  may process measurements of the radiation pattern of CUT  60  to determine whether CUT  60  exhibits satisfactory radio-frequency performance (e.g., to determine whether antennas in CUT  60  exhibit sufficient gain at desired beam steering angles). 
     Test probes  58  may include one or more antenna elements (sometimes referred to herein as test antenna elements) that are used to receive the radio-frequency test signals transmitted by CUT  60  (e.g., to identify the radiation pattern of CUT  60 ). In one suitable arrangement that is described herein as an example, the antenna elements in test probe  58  are implemented using dipole antenna structures. Antenna elements that are implemented using dipole antenna structures may sometimes be referred to herein as dipole elements.  FIG. 5  is a diagram of an illustrative test probe  68  having a dipole element for receiving the radio-frequency test signals transmitted by CUT  60 . 
     As shown in  FIG. 5 , test probe  68  may include dipole antenna element such as dipole element  72  (sometimes referred to herein as dipole  72 , dipole antenna element  72 , dipole antenna  72 , test dipole  72 , or test dipole element  72 ). Dipole element  72  may be formed using conductive traces printed (patterned) on an underlying dielectric substrate such as dielectric substrate  82 . The conductive traces may include copper, silver, gold, indium tin oxide, and/or other materials. In some suitable arrangement, the conductive traces may include metal traces (e.g., copper or silver traces) coupled to underlying indium tin oxide traces. Dielectric substrate  82  may be formed from glass, plastic, polymer, ceramic, and/or any other desired dielectric materials. Dipole element  72  may include a first dipole arm  75 - 1  and a second dipole arm  75 - 2 . A diode such as diode  74  may be coupled between dipole arms  75 - 1  and  75 - 2 . Diode  74  may, for example, be surface-mounted to dielectric substrate  82 . Dipole arms  75 - 1  and  75 - 2  may each have length  81 . Length  81  may be less than the wavelength of the radio-frequency test signals transmitted by the circuitry under test. This may allow the dipole arms to perform test measurements without significantly perturbing the electric field in the vicinity of dipole element  72 . Length  81  may be, for example, between 0.6 mm and 1.0 mm, between 0.4 mm and 1.2 mm, or other lengths. 
     Dipole element  72  may be coupled to conductive contact pads  80  on dielectric substrate  82  over transmission line  76 . Transmission line  76  may include a first conductive line that couples dipole arm  75 - 1  to a first contact pad  80  and a second conductive line that couples dipole arm  75 - 2  to a second contact pad  80 . Contact pads  80  may be coupled to test measurement circuitry  70  over signal paths  78 . Test measurement circuitry  70  may include analog-to-digital converter circuitry, voltmeter circuitry, and/or any other desired circuitry for measuring radio-frequency signals received at dipole element  72 . 
     During radio-frequency test operations, dipole element  72  may receive radio-frequency test signals transmitted by circuitry under test (e.g., CUT  60  of  FIG. 4 ). Dipole element  72  may serve as an electric field probe for the received radio-frequency test signals. For example, the electric field component of the received radio-frequency test signals extending parallel to the longitudinal axis of dipole arms  75 - 1  and  75 - 2 , as shown by arrow  73 , may produce corresponding antenna currents on dipole arms  75 - 1  and  75 - 2 . Diode  74  may serve as a rectifier that converts the radio-frequency antenna currents to a rectified voltage between dipole arms  75 - 1  and  75 - 2 . 
     Transmission line  76  may be configured to form a low pass filter for dipole element  72 . This may serve to prevent scattering of the radio-frequency test signals by transmission line  76  and to prevent radio-frequency currents from passing to test measurement circuitry  70  from dipole element  72 . Transmission line  76  may have length  79  extending from dipole element  72  to contact pads  80 . The first and second conductive lines in transmission line  76  may be separated by distance  77 . The material used to form transmission line  76 , length  79 , and/or distance  77  may be selected to provide transmission line  76  with a relatively high resistance (e.g., a resistance greater than 1 MΩ) that configures transmission line  76  to serve as a low pass filter (e.g., a filter that blocks radio-frequency signals at frequencies greater than 700 MHz while passing lower frequencies). Length  79  may be, for example, between 10 cm and 30 cm, between 1 cm and 40 cm, between 5 cm and 35 cm, between 10 cm and 20 cm, greater than 1 cm, greater than 10 cm, greater than 20 cm, etc. Distance  77  may be, for example, between 25 and 30 microns, between 20 and 35 microns, between 15 and 40 microns, between 10 and 50 microns, greater than 10 microns, greater than 20 microns, less than 30 microns, less than 50 microns, etc. Transmission line  76  may be formed using conductive traces on dielectric substrate  82 . The conductive traces may be formed from a relatively high-resistance conductive material such as indium tin oxide (ITO), graphene, other thin-films, or other materials. In general, length  79  may be lower when transmission line  76  is formed using materials with greater resistivity and may be higher when transmission line  76  is formed using materials with lower resistivity (e.g., to configure transmission line  76  to exhibit a resistance per length that is greater than a minimum resistance per length threshold value that allows the transmission line to convert the rectified voltage into a direct current voltage). 
     Forming a low pass filter using transmission line  76  may allow the transmission line to filter the rectified voltage to produce a direct current (DC) voltage. Test measurement circuitry  70  may sense (measure) the rectified voltage (e.g., the DC voltage) across contact pads  80 . In general, the sensed DC voltage is proportional to the magnitude of the electric field of the received radio-frequency signals (e.g., the magnitude of the component of the electric field parallel to arrow  73 ). Test measurement circuitry  70  and/or the test host (e.g., test host  62  of  FIG. 4 ) may convert the sensed DC voltage into electric field magnitude values by multiplying the sensed DC voltage by a constant value. The test data provided by test measurement circuitry  70  to the test host  62  may include the DC voltages and/or the electric field magnitude values gathered by test measurement circuitry  70 . Test probe  68  may be used to gather the DC voltage and electric field magnitude from the transmitted radio-frequency test signals at multiple points over the circuitry under test. This may allow the wireless test equipment to characterize the transmitted radio-frequency test signals across the entire field of view of the circuitry under test and thus the radiation pattern of the circuitry under test. 
     Test probe  68  of  FIG. 5  may only be capable of measuring a single linear component (e.g., polarization) of the received radio-frequency test signals. For example, test probe  68  may measure the electric field component extending parallel to arrow  73 . The electric field component of the received radio-frequency test signals orthogonal to arrow  73  may not produce antenna currents on dipole arms  75 - 1  and  75 - 2  or a DC voltage across dipole element  72 . If desired, test probe  68  may include additional dipole elements oriented perpendicular to each other to measure the electric field component orthogonal to arrow  73 . In another suitable arrangement, test probe  68  of  FIG. 5  may be rotated over time to measure different electric field components using a single dipole element. 
       FIG. 6  is a flow chart of illustrative steps that may be performed by test system  56  of  FIG. 4  for performing radio-frequency test operations on CUT  60  (e.g., using one or more test probes  68 ). CUT  60  may include at least phased antenna array  54  of  FIG. 3 . 
     At step  84 , CUT  60  is placed onto test fixture  66  of  FIG. 4 . Test fixture  66  may hold CUT  60  in place during testing. CUT  60  may be mounted to test fixture  66  by an operator of test system  56  or by automated test equipment. 
     At step  86 , test host  62  may control the phased antenna array in CUT  60  to transmit radio-frequency test signals (e.g., by conveying control signals to test equipment  58  over data path  64  of  FIG. 4 ). CUT  60  may subsequently transmit the radio-frequency test signals towards one or more test probe  68 . 
     At step  88 , one or more test probes  68  may measure the radiation pattern for CUT  60  based on the transmitted radio-frequency test signals. For example, dipole element  72  and diode  74  on test probe  68  ( FIG. 5 ) may produce a rectified voltage in response to the electric field component of the transmitted radio-frequency test signals that extends parallel to dipole arms  75 - 1  and  75 - 2  of dipole element  72 . Test measurement circuitry  70  may measure the rectified voltage (e.g., the DC voltage generated by the transmission line after filtering the rectified voltage). Test measurement circuitry  70  and/or test host  62  may convert the DC voltage to an electric field magnitude value (sometimes referred to as an electric field strength value) by multiplying the DC voltage by a constant value. 
     Test probe  68  and test measurement circuitry  70  may gather DC voltages and/or electric field magnitude values at multiple positions within the field of view of the phased antenna array in CUT  60 . For example, the test host may control CUT  60  to scan over different beam steering angles (e.g., all possible beam steering angles) while transmitting the radio-frequency test signals. The test equipment may gather corresponding DC voltages and electric field magnitude values for each of the beam steering angles. 
     If desired, test probe  68  may gather DC voltages and/or electric field magnitude values at multiple distances from CUT  60 . This may allow the test system (e.g., test host  62 ) to calculate the phase of the radio-frequency test signals (e.g., at the plane of CUT  60 ) in addition to the electric field magnitudes. The electric field magnitudes and optionally the phases sampled at different locations may provide information about the radiation pattern of CUT  60  (sometimes referred to herein as the measured radiation pattern of CUT  60 ). Test measurement circuitry  70  may convey the electric field magnitudes and DC voltages as test data to test host  62 . 
     At step  90 , test host  62  may analyze the measured radiation pattern of CUT  60  received from test measurement circuitry  70 . For example, test host  62  may determine whether CUT  60  has passed or failed testing by comparing the measured radiation pattern of CUT  60  (e.g., as identified by the DC voltages, electric field magnitudes, and/or phases in the test data) to a predetermined or expected radiation pattern for CUT  60 . If the measured radiation pattern differs excessively from the predetermined radiation pattern, CUT  60  may be labeled as failing testing, may be scrapped, may be re-designed, may be provided to other test equipment for performing additional testing, and/or may be re-assembled. If the measured radiation pattern matches or is sufficiently close to the predetermined radiation pattern, CUT  60  may be labeled as passing testing, may be further assembled into wireless circuitry  34  ( FIG. 1 ), may be assembled into a completed device  10 , and/or may be provided to other test equipment for performing additional testing. 
     If desired, test probe  68  may include multiple dipole elements  72  for concurrently sampling the electric field (radiation pattern) of CUT  60  at multiple locations. In one suitable arrangement, test probe  68  may be a planar test probe having multiple dipole elements  72 .  FIG. 7  is a bottom-up view of a planar test probe having multiple dipole elements. 
     As shown in  FIG. 7 , test probe  68  may be configured as a planar test probe  68 P. Planar test probe  68 P may include multiple dipole elements  72 V and  72 H formed on a lateral (bottom) surface of dielectric substrate  82 . Dipole elements  72 V and  72 H may, for example, be concurrently patterned onto dielectric substrate  82  during an indium tin oxide deposition process. Planar test probe  68 P may be configured to sample different (e.g., orthogonal) electric field components of the received radio-frequency test signals. For example, dipole elements  72 H may sample the electric field component extending parallel to the X-axis whereas dipole elements  72 V sample the electric field component extending parallel to the Y-axis. Dipole elements  72 V may be interspersed or interleaved among dipole elements  72 H on planar test probe  68 P. For example, dipole elements  72 V and dipole elements  72 H may be arranged in an array (e.g., an array having alternating rows and/or columns of dipole elements  72 V and  72 H) or in other patterns. 
     Test measurement circuitry  70  may be mounted to one or more sides of planar test probe  68 P. Transmission lines (e.g., transmission lines  76  of  FIG. 5 , not shown in  FIG. 7  for the sake of clarity) may route rectified voltages measured by each dipole element  72 V and each dipole element  72 H to test measurement circuitry  70 . In one suitable arrangement dipole elements  72 V may be coupled to test measurement circuitry  70  mounted to a first side of dielectric substrate  82  whereas dipole elements  72 H are coupled to test measurement circuitry  70  mounted to a second side of dielectric substrate  82 . 
     During radio-frequency test operations (e.g., while processing step  88  of  FIG. 6 ), the diodes  74  on each dipole element  72 V and each dipole element  72 H may produce rectified voltages in response to radio-frequency test signals transmitted by CUT  60  ( FIG. 4 ) and received at planar test probe  68 P. The rectified voltages may be sampled (e.g., as DC voltages) by test measurement circuitry  70 . Test measurement circuitry  70  and/or test host  62  ( FIG. 4 ) may convert the DC voltages into electric field magnitude values. This may allow the test host to identify the electric field magnitude of the radio-frequency test signals at different locations across the lateral area of planar test probe  68 P (e.g., at different X and Y coordinates). The test host may use the electric field magnitude values gathered by dipole elements  72 H to interpolate the magnitude of the electric field component parallel to the X-axis at the locations of dipole elements  72 V. Similarly, the test host may use the electric field magnitude values gathered by dipole elements  72 V to interpolate the magnitude of the electric field component parallel to the Y-axis at the locations of dipole elements  72 H. In this way, the test host may identify the electric field strength of the radio-frequency test signals across the X-Y plane of  FIG. 7  and thus the radiation pattern for the circuitry under test. 
       FIG. 8  is a cross-sectional side view showing how a planar test probe such as planar test probe  68 P of  FIG. 7  may be used to measure the radiation pattern of circuitry under test. As shown in  FIG. 8 , CUT  60  may include a phased antenna array  54  having two or more antennas  40 . CUT  60  may be mounted to test fixture  66  in test equipment  58 . 
     Dipole elements  72  and diodes  74  may be formed at bottom (lateral) surface  99  of dielectric substrate  82  in planar test probe  68 P. Planar test probe  68 P may be held at distance  94  from CUT  60  with bottom surface  99  facing CUT  60  (e.g., by an operator of test equipment  58 , by additional test fixture hardware, by automated equipment, etc.). During radio-frequency test operations, the test host may control CUT  60  to transmit radio-frequency test signals  95  (e.g., while processing step  86  of  FIG. 6 ). Phased antenna array  54  on CUT  60  may exhibit a radiation pattern envelope  92 . Radiation pattern envelope  92  may be a curve representing change in maximum gain for phased antenna array  54  under all possible beam steering settings (e.g., over the entire field of view for the phased antenna array). 
     Dipole elements  72  and diodes  74  may generate rectified voltages in response to the radio-frequency test signals. The test measurement circuitry may sense the rectified voltages (e.g., as DC voltages). The test measurement circuitry and/or the test host may convert the sensed DC voltages into electric field magnitude values. These operations may be performed concurrently for each dipole element  72  in planar test probe  68 P. Phased antenna array  54  may scan over all possible beam steering angles while transmitting radio-frequency test signals  95 . In this way, planar test probe  68 P may be used to measure electric field magnitude values for the transmitted radio-frequency test signals and thus radiation pattern envelope  92  at multiple locations in the X-Y plane of  FIG. 8 . 
     If desired, test equipment  58  may also be used to calculate the phase of radio-frequency test signals  95 . In order to calculate the phase of the transmitted radio-frequency test signals, planar test probe  68 P may gather electric field magnitude values at multiple distances with respect to phased antenna array  54 . For example, after planar test probe  68 P has been used to gather electric field magnitude values at distance  94  from CUT  60 , planar test probe  68 P may be moved to distance  98  from CUT  60 , as shown by arrow  100 . Planar test probe  68 P may then be used to gather electric field magnitude values at distance  98  from CUT  60 . The test measurement circuitry and/or the test host may use the known distances  94  and  98  and the gathered electric field magnitude values at distances  94  and  98  to determine the phase of the radio-frequency test signals transmitted by CUT  60 . 
     The test host may use the electric field magnitude values gathered at distance  94 , the electric field magnitude values gathered at distance  98 , the DC voltages measured at distance  94 , the DC voltages measured at distance  98 , and/or the calculated phases of radio-frequency test signals  95  to determine whether CUT  60  exhibits satisfactory radio-frequency performance. These values may be used to determine whether radiation pattern envelope  92  (or the radiation pattern of phased antenna array  54  at one or more beam steering angles) matches a predetermined satisfactory radiation pattern (e.g., a predetermined satisfactory radiation pattern envelope). For example, if the measured radiation pattern envelope exhibits undesirable gain nulls or an excessively non-uniform shape, CUT  60  may be marked as failing the radio-frequency test operation (e.g., while processing step  90  of  FIG. 6 ). The example of  FIG. 8  is merely illustrative. If desired, electric field strength may be measured at more than two distances from CUT  60 . 
       FIG. 9  is a flow chart of illustrative steps associated with performing radio-frequency test operations on CUT  60  using planar test probe  68 P. The steps of  FIG. 9  may, for example, be performed while processing steps  88  and  90  of  FIG. 6 . 
     At step  102  of  FIG. 9 , planar test probe  68 P may be set a first height over CUT  60 . For example, planar test probe  68 P may be located at distance  94  from CUT  60  ( FIG. 8 ). 
     At step  104 , planar test probe  68 P may measure the DC voltage V and electric field magnitude |E| 2  of the radio-frequency test signals at the location of each dipole element, where “E” is the electric field vector of the transmitted radio-frequency test signals. As an example, dipole elements  72 H of planar test probe  68 P ( FIG. 5 ) may measure the magnitude of the electric field component parallel to the X-axis of  FIGS. 7 and 8 . Similarly, dipole elements  72 V of planar test probe  68 P may measure the magnitude of the electric field component parallel to the Y-axis. The test measurement circuitry and/or the test host may perform interpolation operations on these measurements to determine (e.g., estimate) the magnitude of the electric field component parallel to the Y-axis at the locations of dipole elements  72 H and the magnitude of the electric field component parallel to the X-axis at the locations of dipole elements  72 V. In this way, the test host may have information about the electric field at the location of each dipole element in the planar test probe regardless of the polarization of the radio-frequency test signals and may use this information to determine the radiation pattern for CUT  60 . 
     At step  106 , planar test probe  68 P may be set to a second height over CUT  60 . For example, planar test probe  68 P may be located to distance  98  from CUT  60  ( FIG. 8 ). 
     At step  108 , planar test probe  68 P may measure the DC voltage V and electric field magnitude |E| 2  of the radio-frequency test signals at the location of each dipole element. The test measurement circuitry and/or the test host may perform interpolation operations on these measurements to determine (e.g., estimate) the magnitude of the electric field component parallel to both the Y-axis and the X-axis across the lateral area of the planar test probe. In this way, the test host may have information about the electric field at the location of each dipole element in the planar test probe regardless of polarization of the radio-frequency test signals and may use this information to determine the radiation pattern for CUT  60 . 
     At step  108 , the test measurement circuitry and/or the test host may compute the phase of the radio-frequency test signals by comparing the measurements obtained while processing step  104  to the measurements obtained while processing step  108 . 
     At step  112 , the test host may characterize the radio-frequency performance of CUT  60  using the measurements obtained while processing steps  104  and  108  and/or using the phase computed while processing step  110 . For example, the test host may use these measurements, which are indicative of the radiation pattern of CUT  60 , to a predetermined satisfactory radiation pattern (e.g., a predetermined satisfactory radiation pattern envelope). If the measured radiation pattern of CUT  60  matches the predetermined satisfactory radiation pattern, CUT  60  may be labeled as passing testing. If the measured radiation pattern of CUT  60  deviates excessively from the predetermined satisfactory radiation pattern, CUT  60  may be labeled as failing testing, may be scrapped, may be reworked, may be redesigned, etc. 
     The example of  FIG. 9  is merely illustrative. If desired, steps  106 - 110  may be omitted. Similar operations may be used in scenarios where the test probe includes only one or two dipole elements rather than an M-by-N array of dipole elements formed on a planar test probe (e.g., wherein M and N are each greater than or equal to two). In one suitable arrangement, the test probe may be formed from one or more substrates that are oriented vertically with respect to CUT  60 . Test probes of this type may sometimes be referred to herein as vertical test probes  68 V. 
       FIG. 10  is a side view of an illustrative vertical test probe  68 V. As shown in  FIG. 10 , vertical test probe  68 V may include contact pads  80  and transmission line  76  on lateral surface  115  of dielectric substrate  82 . Dipole element  72  may be formed from conductive traces  114  at the intersection of bottom surface (side)  116  and lateral surface  115  of dielectric substrate  82  (e.g., conductive traces  114  may be formed on lateral surface  115  at the edge of lateral surface defined by bottom surface  116 , may be formed on bottom surface  116  itself, or may be formed on both bottom surface  116  and lateral surface  115 ). Bottom surface  116  is perpendicular to lateral surface  115  in this example. Diode  74  may be mounted to lateral surface  115  or bottom surface  116 . During radio-frequency test operations, vertical test probe  68 V may be held over circuitry under test with bottom surface  116  facing the circuitry under test. 
     In the example of  FIG. 10 , vertical test probe  68 V only measures a single component of the received radio-frequency test signals (e.g., vertical test probe  68 V of  FIG. 10  measures the magnitude of the electric field component parallel to the X-axis of  FIG. 10 ). If desired, vertical test probe  68 V may include multiple perpendicular dipole elements  72  for concurrently measuring different orthogonal electric field components of the received radio-frequency test signals. 
       FIG. 11  is a bottom perspective view of an illustrative vertical test probe  68 V having multiple dipole elements for concurrently measuring different orthogonal electric field components. As shown in  FIG. 11 , vertical test probe  68 V may include a first pair of contacts pads  80  and a first transmission line  76  on lateral surface  120  of dielectric substrate  82 . Vertical test probe  68 V may also include a second pair of contact pads  80  and a second transmission line  76  on lateral surface  118  of dielectric substrate  82 . Lateral surface  118  may be perpendicular to lateral surface  120 . Vertical test probe  68 V may include a first dipole element  72 V formed from conductive traces at the intersection of lateral surface  120  and bottom surface  116 . Vertical test probe  68 V may also include a second dipole element  72 H formed from conductive traces at the intersection of lateral surface  118  and bottom surface  116 . Dipole elements  72 H and  72 V may measure orthogonal electric field components of the radio-frequency test signals. The examples of  FIGS. 10 and 11  are merely illustrative. If desired, dielectric substrate  82  may have other shapes. 
     A single vertical test probe  68 V may be used to measure the radio-frequency test signals at different locations above CUT  60  or multiple vertical test probes  68 V may be used to concurrently measure the radio-frequency test signals at different locations above CUT  60 .  FIG. 12  is a side view showing how a single vertical test probe  68 V may be used to measure the radio-frequency test signals at different locations above CUT  60 . 
     As shown in  FIG. 12 , test equipment  58  may include a mechanical positioner such as mechanical positioner  122 . Vertical test probe  68 V may be mounted to mechanical positioner  122 . Mechanical positioner  122  may hold vertical test probe  68 V in place over CUT  60  with bottom surface  116  of vertical test probe  68 V facing CUT  60 . Mechanical positioner  122  may include a translational positioner, a rotational positioner, a telescoping positioner, a robotic arm, and/or any other desired equipment for adjusting the position of vertical test probe  68 V relative to CUT  60 . 
     Mechanical positioner  122  may adjust the separation between CUT  60  and vertical test probe  68 V as shown by arrow  124  (e.g., to measure the phase of radio-frequency test signals  95 ), may adjust the lateral position of vertical test probe  68 V over CUT  60  as shown by arrow  126 , and/or may rotate vertical test probe  68 V about its longitudinal axis, as shown by arrow  128 . Vertical test probe  68 V may include a single dipole element as shown in  FIG. 10  or may include multiple orthogonal dipole elements as shown in  FIG. 11 . In scenarios where vertical test probe  68 V includes a single dipole element, mechanical positioner  122  may rotate vertical test probe  68 V (e.g., as shown by arrow  128 ) to measure different electric field components of the radio-frequency test signals  95  transmitted by CUT  60 . Mechanical positioner  122  may adjust the position of vertical test probe  68 V to measure the electric field strength and/or calculate the phase of the radio-frequency test signals transmitted by CUT  60  at different locations (e.g., to measure the radiation pattern and/or radiation pattern envelope of CUT  60 ). 
     In another suitable arrangement, multiple vertical test probes  68 V may be held over CUT  60  for concurrently measuring the radio-frequency test signals at multiple positions. In one suitable arrangement, the vertical test probes may be arranged in a vertical test probe array.  FIG. 13  is a cross-sectional side view of an illustrative vertical test probe array. 
     As shown in  FIG. 13 , vertical test probe array  130  may include multiple vertical test probes  68 V (e.g., vertical test probes having a single dipole element as shown in  FIG. 10  and/or vertical test probes having orthogonal dipole elements as shown in  FIG. 11 ). Vertical test probes  68 V may be arranged in a grid pattern having rows and columns or in any other desired pattern in vertical test probe array  130 . Vertical test probes  68 V (e.g., dielectric substrates  82 ) may be embedded within insulator member  132 . Insulator member  132  may separate each vertical test probe  68 V from the other vertical test probes in vertical test probe array  130  and may help to hold vertical test probes  68 V in place. Insulator member  132  may include plastic, foam, ceramic, or any other desired dielectric materials. 
     Insulator member  132  and vertical test probes  68 V may be mounted to a substrate such as printed circuit board  136 . Printed circuit board  136  may include conductive traces coupled to the contact pads on each vertical test probe  68 V (e.g., contact pads  80  as shown in  FIGS. 10 and 11 ) via a corresponding connector  140 . The conductive traces on printed circuit board  136  may couple connectors  140  to printed circuit board connector  138 . Printed circuit board connector  138  may be coupled to test measurement circuitry  70  and/or test host  62  ( FIG. 4 ). If desired, an absorber layer  134  may be formed over insulator member  132 . Absorber layer  134  may help to mitigate radio-frequency interference from energy reflected off of printed circuit board  136  back towards vertical test probes  68 V. 
     During radio-frequency test operations, vertical test probe array  130  may be held over the circuitry under test with bottom surface  141  facing the circuitry under test. Bottom surface  116  of vertical test probes  68 V may lie flush with bottom surface  141  of vertical test probe array  130 , for example. Vertical test probe array  130  may sample the electric field magnitude of the radio-frequency test signals transmitted by the circuitry under test (e.g., vertical test probe array  130  may replace planar test probe  68 P of  FIG. 8  and may be used to perform radio-frequency testing using the steps of  FIG. 9 ). 
     In scenarios where vertical test probe array  130  includes vertical test probes with a single dipole element (e.g., as shown in  FIG. 10 ), the vertical test probes may be arranged in a pattern that allows vertical test probe array  130  to sample orthogonal electric field components of the transmitted radio-frequency test signals, as shown in the bottom-up view of  FIG. 14 . Insulator member  132  and printed circuit board  136  of  FIG. 13  have been omitted from  FIG. 14  for the sake of clarity. Insulator member  132  may be omitted from vertical test probe array  130  if desired. 
     As shown in  FIG. 14 , vertical test probe array  130  may include vertical test probes  68 V having dipole elements  72 V oriented parallel to the Y-axis and may include vertical test probes  68 V having dipole elements  72 H oriented parallel to the X axis. Bottom surface  116  of vertical test probes  68 V may face the circuitry under test. The vertical test probes  68 V having dipole elements  72 V and the vertical test probes  68 V having dipole elements  72 H may be arranged in an interleaved grid pattern (e.g., a rectangular grid pattern having alternating rows of dipole elements  72 H and  72 V). The test host and/or test measurement circuitry may interpolate the magnitude of the electric field component parallel to the Y-axis for the X-Y locations of dipole elements  72 H using the electric field magnitude values gathered using dipole elements  72 V. Similarly, the test host and/or test measurement circuitry may interpolate the magnitude of the electric field component parallel to the X-axis for the X-Y locations of dipole elements  72 V using the electric field magnitude values measured using dipole elements  72 H. In this way, the test host may characterize the radiation pattern for the circuitry under test regardless of the polarization of the radio-frequency test signals across the lateral area of vertical test probe array  130 . 
     If care is not taken, in scenarios where planar test probe  68 P of  FIGS. 7 and 8  is used to perform radio-frequency testing, the radio-frequency signals transmitted by the circuitry under test may reflect off of different portions of the test equipment to produce undesirable signal interference at the dipole elements. This undesirable interference may produce errors in the rectified voltages and electric field magnitude values gathered by each of the dipole elements. In one suitable arrangement, the planar probe array may include additional layers of dielectric material that are configured to mitigate undesirable interference at the dipole elements. 
       FIG. 15  is a side view showing how planar test probe  68 P may be provided with additional layers of dielectric material that are configured to mitigate interference at dipole elements  72 . As shown in  FIG. 15 , planar test probe  68 P may include dipole elements  72  mounted to bottom surface  99  of dielectric substrate  82 . During radio-frequency testing, bottom surface  99  may face the circuitry under test. 
     The circuitry under test may transmit radio-frequency test signals  146  towards planar test probe  68 P. Due to discontinuities in dielectric permittivity, radio-frequency test signals  146  may reflect off of the interfaces (surfaces) of dielectric substrate  82  and towards dipole elements  72 , as shown by arrows  146 ′. If care is not taken, this reflected energy may undesirably interfere with the measurements performed using dipole elements  72 . 
     As shown in  FIG. 15 , additional dielectric layers such as dielectric layers  142  and  144  may be layered over dielectric substrate  82 . Dielectric substrate  82 , dielectric layer  142 , and dielectric layer  144  may be configured to minimize the amount of reflected radio-frequency energy at dipole elements  72 . For example, dielectric layer  144  may be formed from a material having dielectric constant d k1  and may have thickness  150 . Dielectric layer  142  may be formed from a material having dielectric constant d k2  and may have thickness  148 . Dielectric substrate  82  may be formed from a material having dielectric constant d k3  and may have thickness  147 . Dielectric constant d k1 , dielectric constant d k2 , dielectric constant d k3 , thickness  150 , thickness  148 , and/or thickness  147  may be selected to minimize the presence of reflected radio-frequency energy at dipole elements  72 . 
     For example, these values may be selected so that the radio-frequency signals reflected off of the boundary between dielectric layer  142  and dielectric substrate  82  and/or the radio-frequency signals reflected off of the boundary between dielectric layer  144  and free space destructively interfere with the radio-frequency signals reflected off of the boundary between substrate  82  and dielectric layer  142 . Thicknesses  150  and  148  may, for example, be selected to be approximately one-eight or one-quarter of the effective wavelength of radio-frequency test signals  146 . The effective wavelength may be equal to the free space wavelength multiplied by a constant based on the dielectric constant through which the signals propagate (e.g., dielectric constant d k1 , d k2 , etc.). This may serve to minimize the magnitude of reflected radio-frequency signals at the location of dipole elements  72 , thereby mitigating interference with the measurements gathered using dipole elements  72 . The example of  FIG. 15  is merely illustrative. If desired, more than two dielectric layers may be layered over dielectric substrate  82  or only one of dielectric layers  144  and  142  may be used. 
     In practice, the radio-frequency test signals may also reflect off of the circuitry under test back towards dipole elements  72 . If care is not taken, this reflected energy may also undesirably interfere with measurements gathered using the dipole elements. As shown in  FIG. 16 , planar test probe  68 P may be provided with an absorber layer  151  mounted to bottom surface  99  of dielectric substrate  82  under dipole elements  72 . Absorber layer  151  may be formed using foam or other dielectric materials. 
     During radio-frequency test operations, the circuitry under test may transmit radio-frequency test signals  153 . Radio-frequency test signals  153  may reflect off of bottom surface  99  of dielectric substrate  82 , as shown by reflected signals  153 ′. Reflected signals  153 ′ may reflect off of the circuitry under test back towards dipole elements  72 , as shown by reflected signals  153 ″. Absorber layer  151  may absorb and attenuate reflected signals  153 ′ and  153 ″ to minimize the effect of reflected signals  153 ″ on the measurements gathered using dipole elements  72 . 
     The example of  FIG. 16  is merely illustrative. If desired, more than one absorber layer may be used. Planar test probe  68 P may be provided with additional dielectric layers  142  and  144  of  FIG. 15  and absorber layer  151  if desired. Additional dielectric layers  142  and  144  of  FIG. 15  may be provided over vertical test probe array  130  of  FIGS. 13 and 14  and/or absorber layer  151  of  FIG. 16  may be provided under vertical test probe array  130  of  FIGS. 13 and 14  if desired. 
     If desired, multiple planar test probes  68 P may be used to concurrently measure the radio-frequency test signals transmitted by the circuitry under test at different distances with respect to the circuitry under test.  FIG. 17  is a diagram showing how multiple planar test probes may be used to concurrently measure the radio-frequency test signals. 
     As shown in  FIG. 17 , test equipment  58  may include a first planar test probe  68 P- 1  located at distance  98  from CUT  60  and a second planar test probe  68 P- 2  located at distance  94  from CUT  60 . CUT  60  may transmit radio-frequency test signals  152 . Planar test probes  68 P- 1  and  68 P- 2  may concurrently gather DC voltage and/or electric field magnitude values for radio-frequency test signals  152 . The test measurement circuitry and/or test host may gather phase information for the radio-frequency test signals using the gathered electric field magnitudes and the known distance between planar test probes  68 P- 1  and  68 P- 2 . Performing radio-frequency test operations in this way may take less time than in scenarios where a single planar test probe is moved between distances  98  and  94  (as shown in  FIG. 8 ). At the same time, the presence of planar test probe  68 P- 2  may at least partially attenuate radio-frequency test signals  152  before the test signals reach planar test probe  68 P- 1 . 
       FIG. 18  is a cross-sectional side view showing how dipole element  72  may be formed on a surface of dielectric substrate  82 . As shown in  FIG. 18 , dipole element  72  may be mounted to surface  158  of dielectric substrate  82 . Surface  158  may be bottom surface  116  of vertical test probe  68 V ( FIGS. 10-14 ) or may be bottom surface  99  of planar test probe  68 P ( FIGS. 8, 15, and 16 ). Dipole element  72  may include conductive traces  154  patterned directly onto surface  158  of dielectric substrate  82 . In one suitable arrangement, dielectric substrate  82  may be glass and conductive traces  154  may be indium tin oxide traces. An insulating layer such as overcoating  156  may be layered over conductive traces  154  and dielectric substrate  82 . An opening such as opening  159  may be provided in overcoating  156 . Conductive traces  160  may be patterned on overcoating  156  and may contact conductive traces  154  through opening  159 . Conductive traces  160  may form the dipole arms of dipole element  72  (e.g., dipole arms  75 - 1  and  75 - 2  of  FIG. 5 ). As an example, conductive traces  160  may be formed from metal such as copper or silver. The dipole arms may extend parallel to the Y-axis of  FIG. 18 . Diode  74  may be surface-mounted to conductive traces  160 . 
       FIG. 19  is a top-down view showing how dipole element  72  may be mounted to surface  158  of dielectric substrate  82  (e.g., as taken in the direction of arrow  162  of  FIG. 18 ). Overcoating  156  has been omitted from  FIG. 19  for the sake of clarity. As shown in  FIG. 19 , conductive traces  154  may be patterned onto surface  158  of the underlying dielectric substrate  82 . Transmission line  76  may be patterned onto surface  158  and may be coupled to conductive traces  154  (e.g., conductive traces  154  and transmission line  76  may both be formed from the same layer of indium tin oxide on surface  158 ). Conductive traces  160  may be patterned over the underlying conductive traces  154  and may be electrically coupled to conductive traces  154  (e.g., through opening  159  of  FIG. 18 ). Conductive traces  160  may form dipole arms  75 - 1  and  75 - 2  of dipole element  72 . Diode  74  may be mounted over the underlying conductive traces  154 . Diode  74  may include a diode body  164  that is coupled to the underlying conductive traces  160  by diode contacts  166 . Diode contacts  166  may serve to couple diode  74  between dipole arms  75 - 1  and  75 - 2 . The example of  FIGS. 18 and 19  is merely illustrative and, if desired, other layouts may be used to form dipole elements  72  on dielectric substrate  82 . 
     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: 20190318
Publication Date: 20210720
Grant Date: 20210720
Priority Date: 20190318
Inventors: COOPER, AARON J.
TAYEBI, AMIN
BREDESEN, BREANNA E.
DI NALLO, CARLO
WILLIAMS, MICHAEL J.
Kammersgaard, Nikolaj P.
ZHANG, QIAN
ROSCHUK, TYLER R.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q21/062", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01R29/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01R29/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/102", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01R31/2822", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01R29/0878", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B17/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/102", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01R29/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/16", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/062", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 72514980