PATENT DOCUMENT

Publication Number: US-11956023-B2
Application Number: US-202217827329-A
Country: US
Kind Code: B2

Title: Electronic devices with high frequency polarization optimization

Abstract:
A first device may generate optical signals of different polarizations. Photodiodes may use the optical signals to transmit wireless signals at different polarizations and at a frequency greater than 100 GHz using the optical signals. A second device may receive the wireless signals and may convert the wireless signals into optical signals. A Stokes vector receiver on the second device may generate Stokes vectors based on the optical signals. Control circuitry on the second device may use the Stokes vectors generated for a series of training data in the wireless signals to generate a rotation matrix that characterizes polarization rotation between the first and second devices. The control circuitry may multiply wireless data in subsequently received wireless signals by the rotation matrix to mitigate the polarization rotation and other transmission impairments while using minimal resources.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a first antenna radiating element configured to receive a first wireless signal of a first polarization; 
 a first uni-travelling-carrier photodiode (UTC PD) coupled to the first antenna radiating element; 
 a second antenna radiating element configured to receive a second wireless signal of a second polarization that is different from the first polarization; 
 a second UTC PD coupled to the second antenna radiating element; and 
 a receiver coupled to the first UTC PD over a first optical path and coupled to the second UTC PD over a second optical path. 
 
     
     
       2. The electronic device of  claim 1 , wherein the second antenna radiating element at least partially overlaps the first antenna radiating element, the first antenna radiating element comprises a first planar dipole element, and the second antenna radiating element comprises a second planar dipole element oriented orthogonal to the first planar dipole element. 
     
     
       3. The electronic device of  claim 1 , wherein the first polarization is orthogonal to the second polarization. 
     
     
       4. The electronic device of  claim 1 , wherein the receiver comprises a Stokes vector receiver configured to receive a first optical signal over the first optical path and configured to receive a second optical signal over the second optical path. 
     
     
       5. The electronic device of  claim 4 , wherein the Stokes vector receiver comprises:
 a first optical coupler coupled to the first optical path; 
 a second optical coupler coupled to the second optical path; 
 a first photodiode coupled to the first optical coupler and the second optical coupler; 
 a second photodiode; 
 a third photodiode; and 
 a mixing device coupled to the first optical coupler, the second optical coupler, the first photodiode, the second photodiode, and the third photodiode. 
 
     
     
       6. The electronic device of  claim 5 , wherein the first photodiode is configured to generate a first element of a Stokes vector based on the first and second optical signals, the second photodiode is configured to generate a second element of the Stokes vector based on first outputs of the mixing device, and the third photodiode is configured to generate a third element of the Stokes vector based on second outputs of the mixing device. 
     
     
       7. The electronic device of  claim 4 , wherein the Stokes vector receiver is configured to generate a Stokes vector based on the first optical signal and the second optical signal, the electronic device further comprising:
 one or more processors configured to mitigate a polarization rotation between the electronic device and a transmitting device based at least in part on the Stokes vector. 
 
     
     
       8. The electronic device of  claim 1 , further comprising:
 a light source configured to emit an optical local oscillator (LO) signal, wherein the first UTC PD is configured to convert the first wireless signal using the optical LO signal and the second UTC PD is configured to convert the second wireless signal using the optical LO signal. 
 
     
     
       9. The electronic device of  claim 8 , wherein the light source comprises a vertical cavity surface emitting laser (VCSEL). 
     
     
       10. The electronic device of  claim 1 , wherein the receiver comprises:
 a first optical coupler having an input coupled to the first optical path; and 
 a second optical coupler having an input coupled to the second optical path. 
 
     
     
       11. The electronic device of  claim 10 , further comprising:
 a mixing device having a first input coupled to a first output of the first optical coupler and having a second input coupled to a first output of the second optical coupler. 
 
     
     
       12. The electronic device of  claim 11 , further comprising:
 a first photodiode having a first input coupled to a second output of the first optical coupler and having a second input coupled to a second output of the second optical coupler. 
 
     
     
       13. The electronic device of  claim 12 , further comprising:
 a second photodiode; and 
 a third photodiode, the second photodiode and the third photodiode having inputs coupled to outputs of the mixing device. 
 
     
     
       14. The electronic device of  claim 13 , wherein the first photodiode, the second photodiode, and the third photodiode are configured to output respective elements of a Stokes vector. 
     
     
       15. The electronic device of  claim 11 , wherein the mixing device comprises a photonic homodyne receiver. 
     
     
       16. The electronic device of  claim 10 , further comprising:
 a photodiode having a first input coupled to an output of the first optical coupler and having a second input coupled to an output of the second optical coupler. 
 
     
     
       17. The electronic device of  claim 1 , wherein the first wireless signal and the second wireless signal are at one or more frequencies greater than or equal to 100 GHz. 
     
     
       18. Wireless circuitry comprising:
 a first antenna radiating element configured to receive a first wireless signal of a first polarization; 
 a first uni-travelling-carrier photodiode (UTC PD) coupled to the first antenna radiating element; 
 a second antenna radiating element configured to receive a second wireless signal of a second polarization that is different from the first polarization; 
 a second UTC PD coupled to the second antenna radiating element; 
 a substrate; and 
 a receiver on the substrate, wherein the receiver is coupled to the first UTC PD over a first optical path and is coupled to the second UTC PD over a second optical path. 
 
     
     
       19. The wireless circuitry of  claim 18 , wherein the receiver comprises a Stokes vector receiver. 
     
     
       20. A method of operating an electronic device, the method comprising:
 receiving, using a first antenna radiating element and a first uni-travelling-carrier photodiode (UTC PD) coupled to the first antenna radiating element, a first wireless signal of a first polarization; 
 receiving, using a second antenna radiating element and a second UTC PD coupled to the second antenna radiating element, a second wireless signal of a second polarization different from the first polarization; 
 receiving, using a receiver, wireless data from the first wireless signal via a first optical path coupled to the first UTC PD; and 
 receiving, using the receiver, wireless data from the second wireless signal via a second optical path coupled to the second UTC PD.

Description:
This application claims the benefit of U.S. Provisional Patent Application No. 63/247,176, filed Sep. 22, 2021, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This disclosure relates generally to electronic devices and, more particularly, to electronic devices with wireless circuitry. 
     BACKGROUND 
     Electronic devices are often provided with wireless capabilities. An electronic device with wireless capabilities has wireless circuitry that includes one or more antennas. The wireless circuitry is used to perform communications using radio-frequency signals conveyed by the antennas. 
     As software applications on electronic devices become more data-intensive over time, demand has grown for electronic devices that support wireless communications at higher data rates. However, the maximum data rate supported by electronic devices is limited by the frequency of the radio-frequency signals. In addition, if care is not taken, impairments such as misalignment between an electronic device and external equipment can limit communication efficiency in scenarios where signals are conveyed between the electronic device and the external equipment using multiple electromagnetic polarizations. 
     SUMMARY 
     A wireless communication system may include a central optical processor and an access point. The central optical processor may generate first optical signals at a first frequency and having a first polarization, second optical signals at the first frequency and having a second polarization, and third optical signals at a second frequency that is different from the first frequency. An optical combiner may combine the first, second, and third optical signals onto an optical fiber. The optical fiber may illuminate a first photodiode in the access point using the first optical signal and the third optical signal. The optical fiber may illuminate a second photodiode in the access point using the second optical signal and the third optical signal. 
     The first photodiode may transmit first wireless signals having the first polarization over a first antenna radiating element based on the first and third optical signals. The second photodiode may transmit second wireless signals having the second polarization over a second antenna radiating element based on the second and third optical signals. The first and second wireless signals may be transmitted at a frequency greater than or equal to 100 GHz. An electronic device may receive the first and second wireless signals. The first optical signal may be modulated to include a series of training data. The training data may be used by the electronic device to mitigate polarization rotations and other transmission impairments. 
     The electronic device may include a first antenna radiating element that receives the first wireless signals and a second antenna radiating element that receives the second wireless signals. The electronic device may include a first photodiode that converts the first wireless signals to fourth optical signals using an optical local oscillator and a second photodiode that converts the second wireless signals to fifth optical signals using the optical local oscillator. The electronic device may include a Stokes vector receiver that generates Stokes vectors based on the fourth and fifth optical signals. One or more processors on the electronic device may use the Stokes vectors generated for the series of training data to generate a rotation matrix that characterizes the polarization rotation between the electronic device and the wireless communications system. The one or more processors may multiply the wireless data in subsequently received wireless signals by the rotation matrix to mitigate the polarization rotation and other transmission impairments while using minimal resources. 
     An aspect of the disclosure provides an electronic device. The electronic device can include a first antenna radiating element configured to receive a first wireless signal of a first polarization at a frequency greater than or equal to 100 GHz. The electronic device can include a second antenna radiating element configured to receive a second wireless signal of a second polarization that is different from the first polarization. The electronic device can include a first photodiode coupled to the first antenna radiating element and configured to convert the first wireless signal into a first optical signal. The electronic device can include a second photodiode coupled to the second antenna radiating element and configured to convert the second wireless signal into a second optical signal. The electronic device can include a Stokes vector receiver coupled to the first photodiode over a first optical path and coupled to the second photodiode over a second optical path. 
     An aspect of the disclosure provides a method of performing wireless communications using an electronic device. The method can include with one or more antennas, receiving first wireless signals of a first polarization and second wireless signals of a second polarization that is different from the first polarization. The method can include with a first photodiode, converting the first wireless signals into first optical signals. The method can include with a second photodiode, converting the second wireless signals into second optical signals. The method can include with a receiver, generating Stokes vectors based on the first optical signals and the second optical signals. The method can include with one or more processors, generating a rotation matrix based on the Stokes vectors. The method can include with the one or more processors, applying the rotation matrix to wireless data in subsequent wireless signals received using the one or more antennas. 
     An aspect of the disclosure provides a wireless communication system. The wireless communication system can include a first photodiode. The wireless communication system can include a first antenna coupled to the first photodiode. The wireless communication system can include a second photodiode. The wireless communication system can include a second antenna coupled to the second photodiode. The wireless communication system can include a first light source configured to generate a first optical signal at a first frequency and having a first polarization and configured to generate a second optical signal at the first frequency and having a second polarization orthogonal to the first polarization. The wireless communication system can include a second light source configured to generate a third optical signal at a second frequency that is different from the first frequency. The wireless communication system can include an optical combiner configured to combine the first optical signal, the second optical signal, and the third optical signal onto an optical path, the optical path being configured to illuminate the first photodiode using the first optical signal and the third optical signal and being configured to illuminate the second photodiode using the second optical signal and the third optical signal, the first photodiode being configured to transmit first wireless signals having the first polarization over the first antenna based on the first optical signal and the third optical signal, and the second photodiode being configured to transmit second wireless signals having the second polarization over the second antenna based on the second optical signal and the third optical signal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram of an illustrative electronic device having wireless circuitry with at least one antenna that conveys wireless signals at frequencies greater than about 100 GHz in accordance with some embodiments. 
         FIG.  2    is a top view of an illustrative antenna that transmits wireless signals at frequencies greater than about 100 GHz based on optical local oscillator (LO) signals in accordance with some embodiments. 
         FIG.  3    is a top view showing how an illustrative antenna of the type shown in  FIG.  2    may convert received wireless signals at frequencies greater than about 100 GHz into intermediate frequency signals based on optical LO signals in accordance with some embodiments. 
         FIG.  4    is a top view showing how multiple antennas of the type shown in  FIGS.  2  and  3    may be stacked to cover multiple polarizations in accordance with some embodiments. 
         FIG.  5    is a top view showing how stacked antennas of the type shown in  FIG.  4    may be integrated into a phased antenna array for conveying wireless signals at frequencies greater than about 100 GHz within a corresponding signal beam. 
         FIG.  6    is a circuit diagram of illustrative wireless circuitry having an antenna that transmits wireless signals at frequencies greater than about 100 GHz and that receives wireless signals at frequencies greater than about 100 GHz for conversion to intermediate frequencies and then to the optical domain in accordance with some embodiments. 
         FIG.  7    is a circuit diagram of an illustrative phased antenna array that conveys wireless signals at frequencies greater than about 100 GHz within a corresponding signal beam in accordance with some embodiments. 
         FIG.  8    is a diagram showing how an illustrative central optical controller may provide optical signals to an access point for conveying multiple polarizations of wireless signals at frequencies greater than about 100 GHz based on the optical signals in accordance with some embodiments. 
         FIG.  9    is a circuit diagram showing how an illustrative central optical controller may generate optical signals that are provided to an access point for conveying multiple polarizations of wireless signals at frequencies greater than about 100 GHz in accordance with some embodiments. 
         FIG.  10    is a circuit diagram of an illustrative electronic device having a Stokes vector receiver for receiving multiple polarizations of wireless signals at frequencies greater than about 100 GHz in accordance with some embodiments. 
         FIG.  11    is a flow chart of illustrative steps that may be performed by a transmitting device and a receiving device for mitigating transmission impairments associated with the transmission of multiple polarizations of wireless signals at frequencies greater than about 100 GHz in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic device  10  of  FIG.  1    (sometimes referred to herein as electro-optical device  10 ) may be a computing device such as a laptop computer, a desktop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses, goggles, or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, a wireless internet-connected voice-controlled speaker, a home entertainment device, a remote control device, a gaming controller, a peripheral user input device, a wireless base station or access point, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     As shown in the functional block diagram of  FIG.  1   , device  10  may include components located on or within an electronic device housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, metal alloys, etc.), other suitable materials, or a combination of these materials. In some situations, parts or all of housing  12  may be formed from dielectric or other low-conductivity material (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     Device  10  may include control circuitry  14 . Control circuitry  14  may include storage such as storage circuitry  16 . Storage circuitry  16  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. Storage circuitry  16  may include storage that is integrated within device  10  and/or removable storage media. 
     Control circuitry  14  may include processing circuitry such as processing circuitry  18 . Processing circuitry  18  may be used to control the operation of device  10 . Processing circuitry  18  may include on one or more processors, microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application specific integrated circuits, central processing units (CPUs), graphics processing units (GPUs), etc. Control circuitry  14  may be configured to perform operations in device  10  using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing operations in device  10  may be stored on storage circuitry  16  (e.g., storage circuitry  16  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  16  may be executed by processing circuitry  18 . 
     Control circuitry  14  may be used to run software on device  10  such as satellite navigation applications, internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, control circuitry  14  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  14  include internet protocols, wireless local area network (WLAN) protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other wireless personal area network (WPAN) protocols, IEEE 802.11ad protocols (e.g., ultra-wideband protocols), cellular telephone protocols (e.g., 3G protocols, 4G (LTE) protocols, 3GPP Fifth Generation (5G) New Radio (NR) protocols, Sixth Generation (6G) protocols, sub-THz protocols, THz protocols, etc.), antenna diversity protocols, satellite navigation system protocols (e.g., global positioning system (GPS) protocols, global navigation satellite system (GLONASS) protocols, etc.), antenna-based spatial ranging protocols, optical communications protocols, or any other desired communications protocols. Each communications 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  20 . Input-output circuitry  20  may include input-output devices  22 . Input-output devices  22  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  22  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  22  may include touch sensors, displays (e.g., touch-sensitive and/or force-sensitive displays), light-emitting components such as displays without touch sensor capabilities, buttons (mechanical, capacitive, optical, etc.), scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, audio jacks and other audio port components, digital data port devices, motion sensors (accelerometers, gyroscopes, and/or compasses that detect motion), capacitance sensors, proximity sensors, magnetic sensors, force sensors (e.g., force sensors coupled to a display to detect pressure applied to the display), temperature sensors, etc. In some configurations, keyboards, headphones, displays, pointing devices such as trackpads, mice, and joysticks, and other input-output devices may be coupled to device  10  using wired or wireless connections (e.g., some of input-output devices  22  may be peripherals that are coupled to a main processing unit or other portion of device  10  via a wired or wireless link). 
     Input-output circuitry  20  may include wireless circuitry  24  to support wireless communications. Wireless circuitry  24  (sometimes referred to herein as wireless communications circuitry  24 ) may include one or more antennas  30 . 
     Wireless circuitry  24  may also include transceiver circuitry  26 . Transceiver circuitry  26  may include transmitter circuitry, receiver circuitry, modulator circuitry, demodulator circuitry (e.g., one or more modems), radio-frequency circuitry, one or more radios, intermediate frequency circuitry, optical transmitter circuitry, optical receiver circuitry, optical light sources, other optical components, baseband circuitry (e.g., one or more baseband processors), amplifier circuitry, clocking circuitry such as one or more local oscillators and/or phase-locked loops, memory, one or more registers, filter circuitry, switching circuitry, analog-to-digital converter (ADC) circuitry, digital-to-analog converter (DAC) circuitry, radio-frequency transmission lines, optical fibers, and/or any other circuitry for transmitting and/or receiving wireless signals using antennas  30 . The components of transceiver circuitry  26  may be implemented on one integrated circuit, chip, system-on-chip (SOC), die, printed circuit board, substrate, or package, or the components of transceiver circuitry  26  may be distributed across two or more integrated circuits, chips, SOCs, printed circuit boards, substrates, and/or packages. 
     The example of  FIG.  1    is merely illustrative. While control circuitry  14  is shown separately from wireless circuitry  24  in the example of  FIG.  1    for the sake of clarity, wireless circuitry  24  may include processing circuitry (e.g., one or more processors) that forms a part of processing circuitry  18  and/or storage circuitry that forms a part of storage circuitry  16  of control circuitry  14  (e.g., portions of control circuitry  14  may be implemented on wireless circuitry  24 ). As an example, control circuitry  14  may include baseband circuitry (e.g., one or more baseband processors), digital control circuitry, analog control circuitry, and/or other control circuitry that forms part of wireless circuitry  24 . The baseband circuitry may, for example, access a communication protocol stack on control circuitry  14  (e.g., storage circuitry  20 ) to: perform user plane functions at a PHY layer, MAC layer, RLC layer, PDCP layer, SDAP layer, and/or PDU layer, and/or to perform control plane functions at the PHY layer, MAC layer, RLC layer, PDCP layer, RRC, layer, and/or non-access stratum layer. 
     Transceiver circuitry  26  may be coupled to each antenna  30  in wireless circuitry  24  over a respective signal path  28 . Each signal path  28  may include one or more radio-frequency transmission lines, waveguides, optical fibers, and/or any other desired lines/paths for conveying wireless signals between transceiver circuitry  26  and antenna  30 . Antennas  30  may be formed using any desired antenna structures for conveying wireless signals. For example, antennas  30  may include antennas with resonating elements that are formed from dipole antenna structures, planar dipole antenna structures (e.g., bowtie antenna structures), slot antenna structures, loop antenna structures, patch antenna structures, inverted-F antenna structures, planar inverted-F antenna structures, helical antenna structures, monopole antennas, dipoles, hybrids of these designs, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and/or other antenna tuning components may be adjusted to adjust the frequency response and wireless performance of antennas  30  over time. 
     If desired, two or more of antennas  30  may be integrated into a phased antenna array (sometimes referred to herein as a phased array antenna) in which each of the antennas conveys wireless signals with a respective phase and magnitude that is adjusted over time so the wireless signals constructively and destructively interfere to produce (form) a signal beam in a given pointing direction. The term “convey wireless signals” as used herein means the transmission and/or reception of the wireless signals (e.g., for performing unidirectional and/or bidirectional wireless communications with external wireless communications equipment). Antennas  30  may transmit the wireless signals by radiating the signals into free space (or to free space through intervening device structures such as a dielectric cover layer). Antennas  30  may additionally or alternatively receive the wireless signals from free space (e.g., through intervening devices structures such as a dielectric cover layer). The transmission and reception of wireless signals by antennas  30  each involve the excitation or resonance of antenna currents on an antenna resonating (radiating) element in the antenna by the wireless signals within the frequency band(s) of operation of the antenna. 
     Transceiver circuitry  26  may use antenna(s)  30  to transmit and/or receive wireless signals that convey wireless communications data between device  10  and external wireless communications equipment (e.g., one or more other devices such as device  10 , a wireless access point or base station, etc.). The wireless communications data may be conveyed bidirectionally or unidirectionally. The wireless communications 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. 
     Additionally or alternatively, wireless circuitry  24  may use antenna(s)  30  to perform wireless sensing operations. The sensing operations may allow device  10  to detect (e.g., sense or identify) the presence, location, orientation, and/or velocity (motion) of objects external to device  10 . Control circuitry  14  may use the detected presence, location, orientation, and/or velocity of the external objects to perform any desired device operations. As examples, control circuitry  14  may use the detected presence, location, orientation, and/or velocity of the external objects to identify a corresponding user input for one or more software applications running on device  10  such as a gesture input performed by the user&#39;s hand(s) or other body parts or performed by an external stylus, gaming controller, head-mounted device, or other peripheral devices or accessories, to determine when one or more antennas  30  needs to be disabled or provided with a reduced maximum transmit power level (e.g., for satisfying regulatory limits on radio-frequency exposure), to determine how to steer (form) a radio-frequency signal beam produced by antennas  30  for wireless circuitry  24  (e.g., in scenarios where antennas  30  include a phased array of antennas  30 ), to map or model the environment around device  10  (e.g., to produce a software model of the room where device  10  is located for use by an augmented reality application, gaming application, map application, home design application, engineering application, etc.), to detect the presence of obstacles in the vicinity of (e.g., around) device  10  or in the direction of motion of the user of device  10 , etc. 
     Wireless circuitry  24  may transmit and/or receive wireless signals within corresponding frequency bands of the electromagnetic spectrum (sometimes referred to herein as communications bands or simply as “bands”). The frequency bands handled by communications circuitry  26  may include wireless local area network (WLAN) frequency bands (e.g., Wi-Fi® (IEEE 802.11) or other WLAN communications bands) such as a 2.4 GHz WLAN band (e.g., from 2400 to 2480 MHz), a 5 GHz WLAN band (e.g., from 5180 to 5825 MHz), a Wi-Fi® 6E band (e.g., from 5925-7125 MHz), and/or other Wi-Fi® bands (e.g., from 1875-5160 MHz), wireless personal area network (WPAN) frequency bands such as the 2.4 GHz Bluetooth® band or other WPAN communications bands, cellular telephone frequency bands (e.g., bands from about 600 MHz to about 5 GHz, 3G bands, 4G LTE bands, 5G New Radio Frequency Range 1 (FR1) bands below 10 GHz, 5G New Radio Frequency Range 2 (FR2) bands between 20 and 60 GHz, etc.), other centimeter or millimeter wave frequency bands between 10-100 GHz, near-field communications frequency bands (e.g., at 13.56 MHz), satellite navigation frequency bands (e.g., a GPS band from 1565 to 1610 MHz, a Global Navigation Satellite System (GLONASS) band, a BeiDou Navigation Satellite System (BDS) band, etc.), ultra-wideband (UWB) frequency bands that operate under the IEEE 802.15.4 protocol and/or other ultra-wideband communications protocols, communications bands under the family of 3GPP wireless communications standards, communications bands under the IEEE 802.XX family of standards, and/or any other desired frequency bands of interest. 
     Over time, software applications on electronic devices such as device  10  have become more and more data intensive. Wireless circuitry on the electronic devices therefore needs to support data transfer at higher and higher data rates. In general, the data rates supported by the wireless circuitry are proportional to the frequency of the wireless signals conveyed by the wireless circuitry (e.g., higher frequencies can support higher data rates than lower frequencies). Wireless circuitry  24  may convey centimeter and millimeter wave signals to support relatively high data rates (e.g., because centimeter and millimeter wave signals are at relatively high frequencies between around 10 GHz and 100 GHz). However, the data rates supported by centimeter and millimeter wave signals may still be insufficient to meet all the data transfer needs of device  10 . To support even higher data rates such as data rates up to 5-10 Gbps or higher, wireless circuitry  24  may convey wireless signals at frequencies greater than 100 GHz. 
     As shown in  FIG.  1   , wireless circuitry  24  may transmit wireless signals  32  and may receive wireless signals  34  at frequencies greater than around 100 GHz. Wireless signals  32  and  34  may sometimes be referred to herein as tremendously high frequency (THF) signals  32  and  34 , sub-THz signals  32  and  34 , THz signals  32  and  34 , or sub-millimeter wave signals  32  and  34 . THF signals  32  and  34  may be at sub-THz or THz frequencies such as frequencies between 100 GHz and 1 THz, between 100 GHz and 10 THz, between 100 GHz and 2 THz, between 200 GHz and 1 THz, between 300 GHz and 1 THz, between 300 GHz and 2 THz, between 300 GHz and 10 THz, between 100 GHz and 800 GHz, between 200 GHz and 1.5 THz, etc. (e.g., within a sub-THz, THz, THF, or sub-millimeter frequency band such as a 6G frequency band). The high data rates supported by these frequencies may be leveraged by device  10  to perform cellular telephone voice and/or data communications (e.g., while supporting spatial multiplexing to provide further data bandwidth), to perform spatial ranging operations such as radar operations to detect the presence, location, and/or velocity of objects external to device  10 , to perform automotive sensing (e.g., with enhanced security), to perform health/body monitoring on a user of device  10  or another person, to perform gas or chemical detection, to form a high data rate wireless connection between device  10  and another device or peripheral device (e.g., to form a high data rate connection between a display driver on device  10  and a display that displays ultra-high resolution video), to form a remote radio head (e.g., a flexible high data rate connection), to form a THF chip-to-chip connection within device  10  that supports high data rates (e.g., where one antenna  30  on a first chip in device  10  transmits THF signals  32  to another antenna  30  on a second chip in device  10 ), and/or to perform any other desired high data rate operations. 
     Space is at a premium within electronic devices such as device  10 . In some scenarios, different antennas  30  are used to transmit THF signals  32  than are used to receive THF signals  34 . However, handling transmission of THF signals  32  and reception of THF signals  34  using different antennas  30  can consume an excessive amount of space and other resources within device  10  because two antennas  30  and signal paths  28  would be required to handle both transmission and reception. To minimize space and resource consumption within device  10 , the same antenna  30  and signal path  28  may be used to both transmit THF signals  32  and to receive THF signals  34 . If desired, multiple antennas  30  in wireless circuitry  24  may transmit THF signals  32  and may receive THF signals  34 . The antennas may be integrated into a phased antenna array that transmits THF signals  32  and that receives THF signals  34  within a corresponding signal beam oriented in a selected beam pointing direction. 
     It can be challenging to incorporate components into wireless circuitry  24  that support wireless communications at these high frequencies. If desired, transceiver circuitry  26  and signal paths  28  may include optical components that convey optical signals to support the transmission of THF signals  32  and the reception of THF signals  34  in a space and resource-efficient manner. The optical signals may be used in transmitting THF signals  32  at THF frequencies and in receiving THF signals  34  at THF frequencies. 
       FIG.  2    is a diagram of an illustrative antenna  30  that may be used to both transmit THF signals  32  and to receive THF signals  34  using optical signals. Antenna  30  may include one or more antenna radiating (resonating) elements such as radiating (resonating) element arms  36 . In the example of  FIG.  2   , antenna  30  is a planar dipole antenna (sometimes referred to as a “bowtie” antenna) having two opposing radiating element arms  36  (e.g., bowtie arms or dipole arms). This is merely illustrative and, in general, antenna  30  may be any type of antenna having any desired antenna radiating element architecture. 
     As shown in  FIG.  2   , antenna  30  includes a photodiode (PD)  42  coupled between radiating element arms  36 . Electronic devices that include antennas  30  with photodiodes  42  such as device  10  may sometimes also be referred to as electro-optical devices (e.g., electro-optical device  10 ). Photodiode  42  may be a programmable photodiode. An example in which photodiode  42  is a programmable uni-travelling-carrier photodiode (UTC PD) is described herein as an example. Photodiode  42  may therefore sometimes be referred to herein as UTC PD  42  or programmable UTC PD  42 . This is merely illustrative and, in general, photodiode  42  may include any desired type of adjustable/programmable photodiode or component that converts electromagnetic energy at optical frequencies to current at THF frequencies on radiating element arms  36  and/or vice versa. Each radiating element arm  36  may, for example, have a first edge at UTC PD  42  and a second edge opposite the first edge that is wider than the first edge (e.g., in implementations where antenna  30  is a bowtie antenna). Other radiating elements may be used if desired. 
     UTC PD  42  may have a bias terminal  38  that receives one or more control signals V BIAS . Control signals V BIAS  may include bias voltages provided at one or more voltage levels and/or other control signals for controlling the operation of UTC PD  42  such as impedance adjustment control signals for adjusting the output impedance of UTC PD  42 . Control circuitry  14  ( FIG.  1   ) may provide (e.g., apply, supply, assert, etc.) control signals V BIAS  at different settings (e.g., values, magnitudes, etc.) to dynamically control (e.g., program or adjust) the operation of UTC PD  42  over time. For example, control signals V BIAS  may be used to control whether antenna  30  transmits THF signals  32  or receives THF signals  34 . When control signals V BIAS  include a bias voltage asserted at a first level or magnitude, antenna  30  may be configured to transmit THF signals  32 . When control signals V BIAS  include a bias voltage asserted at a second level or magnitude, antenna  30  may be configured to receive THF signals  34 . In the example of  FIG.  2   , control signals V BIAS  include the bias voltage asserted at the first level to configure antenna  30  to transmit THF signals  32 . If desired, control signals V BIAS  may also be adjusted to control the waveform of the THF signals (e.g., as a squaring function that preserves the modulation of incident optical signals, a linear function, etc.), to perform gain control on the signals conveyed by antenna  30 , and/or to adjust the output impedance of UTC PD  42 . 
     As shown in  FIG.  2   , UTC PD  42  may be optically coupled to optical path  40 . Optical path  40  may include one or more optical fibers or waveguides. UTC PD  42  may receive optical signals from transceiver circuitry  26  ( FIG.  1   ) over optical path  40 . The optical signals may include a first optical local oscillator (LO) signal LO 1  and a second optical local oscillator signal LO 2 . Optical local oscillator signals LO 1  and LO 2  may be generated by light sources in transceiver circuitry  26  ( FIG.  1   ). Optical local oscillator signals LO 1  and LO 2  may be at optical wavelengths (e.g., between 400 nm and 700 nm), ultra-violet wavelengths (e.g., near-ultra-violet or extreme ultraviolet wavelengths), and/or infrared wavelengths (e.g., near-infrared wavelengths, mid-infrared wavelengths, or far-infrared wavelengths). Optical local oscillator signal LO 2  may be offset in wavelength from optical local oscillator signal LO 1  by a wavelength offset X. Wavelength offset X may be equal to the wavelength of the THF signals conveyed by antenna  30  (e.g., between 100 GHz and 1 THz (1000 GHz), between 100 GHz and 2 THz, between 300 GHz and 800 GHz, between 300 GHz and 1 THz, between 300 and 400 GHz, etc.). 
     During signal transmission, wireless data (e.g., wireless data packets, symbols, frames, etc.) may be modulated onto optical local oscillator signal LO 2  to produce modulated optical local oscillator signal LO 2 ′. If desired, optical local oscillator signal LO 1  may be provided with an optical phase shift S. Optical path  40  may illuminate UTC PD  42  with optical local oscillator signal LO 1  (plus the optical phase shift S when applied) and modulated optical local oscillator signal LO 2 ′. If desired, lenses or other optical components may be interposed between optical path  40  and UTC PD  42  to help focus the optical local oscillator signals onto UTC PD  42 . 
     UTC PD  42  may convert optical local oscillator signal LO 1  and modulated local oscillator signal LO 2 ′ (e.g., beats between the two optical local oscillator signals) into antenna currents that run along the perimeter of radiating element arms  36 . The frequency of the antenna currents is equal to the frequency difference between local oscillator signal LO 1  and modulated local oscillator signal LO 2 ′. The antenna currents may radiate (transmit) THF signals  32  into free space. Control signal V BIAS  may control UTC PD  42  to convert the optical local oscillator signals into antenna currents on radiating element arms  36  while preserving the modulation and thus the wireless data on modulated local oscillator signal LO 2 ′ (e.g., by applying a squaring function to the signals). THF signals  32  will thereby carry the modulated wireless data for reception and demodulation by external wireless communications equipment. 
       FIG.  3    is a diagram showing how antenna  30  may receive THF signals  34  (e.g., after changing the setting of control signals V BIAS  into a reception state from the transmission state of  FIG.  2   ). As shown in  FIG.  3   , THF signals  34  may be incident upon antenna radiating element arms  36 . The incident THF signals  34  may produce antenna currents that flow around the perimeter of radiating element arms  36 . UTC PD  42  may use optical local oscillator signal LO 1  (plus the optical phase shift S when applied), optical local oscillator signal LO 2  (e.g., without modulation), and control signals V BIAS  (e.g., a bias voltage asserted at the second level) to convert the received THF signals  34  into intermediate frequency signals SIGIF that are output onto intermediate frequency signal path  44 . 
     The frequency of intermediate frequency signals SIGIF may be equal to the frequency of THF signals  34  minus the difference between the frequency of optical local oscillator signal LO 1  and the frequency of optical local oscillator signal LO 2 . As an example, intermediate frequency signals SIGIF may be at lower frequencies than THF signals  32  and  34  such as centimeter or millimeter wave frequencies between 10 GHz and 100 GHz, between 30 GHz and 80 GHz, around 60 GHz, etc. If desired, transceiver circuitry  26  ( FIG.  1   ) may change the frequency of optical local oscillator signal LO 1  and/or optical local oscillator signal LO 2  when switching from transmission to reception or vice versa. UTC PD  42  may preserve the data modulation of THF signals  34  in intermediate signals SIGIF. A receiver in transceiver circuitry  26  ( FIG.  1   ) may demodulate intermediate frequency signals SIGIF (e.g., after further downconversion) to recover the wireless data from THF signals  34 . In another example, wireless circuitry  24  may convert intermediate frequency signals SIGIF to the optical domain before recovering the wireless data. In yet another example, intermediate frequency signal path  44  may be omitted and UTC PD  42  may convert THF signals  34  into the optical domain for subsequent demodulation and data recovery (e.g., in a sideband of the optical signal). 
     The antenna  30  of  FIGS.  2  and  3    may support transmission of THF signals  32  and reception of THF signals  34  with a given polarization (e.g., a linear polarization such as a vertical polarization). If desired, wireless circuitry  24  ( FIG.  1   ) may include multiple antennas  30  for covering different polarizations.  FIG.  4    is a diagram showing one example of how wireless circuitry  24  may include multiple antennas  30  for covering different polarizations. 
     As shown in  FIG.  4   , the wireless circuitry may include a first antenna  30  such as antenna  30 V for covering a first polarization (e.g., a first linear polarization such as a vertical polarization) and may include a second antenna  30  such as antenna  30 H for covering a second polarization different from or orthogonal to the first polarization (e.g., a second linear polarization such as a horizontal polarization). Antenna  30 V may have a UTC PD  42  such as UTC PD  42 V coupled between a corresponding pair of radiating element arms  36 . Antenna  30 H may have a UTC PD  42  such as UTC PD  42 H coupled between a corresponding pair of radiating element arms  36  oriented non-parallel (e.g., orthogonal) to the radiating element arms  36  in antenna  30 V. This may allow antennas  30 V and  30 H to transmit THF signals  32  with respective (orthogonal) polarizations and may allow antennas  30 V and  30 H to receive THF signals  32  with respective (orthogonal) polarizations. 
     To minimize space within device  10 , antenna  30 V may be vertically stacked over or under antenna  30 H (e.g., where UTC PD  42 V partially or completely overlaps UTC PD  42 H). In this example, antennas  30 V and  30 H may both be formed on the same substrate such as a rigid or flexible printed circuit board. The substrate may include multiple stacked dielectric layers (e.g., layers of ceramic, epoxy, flexible printed circuit board material, rigid printed circuit board material, etc.). The radiating element arms  36  in antenna  30 V may be formed on a separate layer of the substrate than the radiating element arms  36  in antenna  30 H or the radiating element arms  36  in antenna  30 V may be formed on the same layer of the substrate as the radiating element arms  36  in antenna  30 H. UTC PD  42 V may be formed on the same layer of the substrate as UTC PD  42 H or UTC PD  42 V may be formed on a separate layer of the substrate than UTC PD  42 H. UTC PD  42 V may be formed on the same layer of the substrate as the radiating element arms  36  in antenna  30 V or may be formed on a separate layer of the substrate as the radiating element arms  36  in antenna  30 V. UTC PD  42 H may be formed on the same layer of the substrate as the radiating element arms  36  in antenna  30 H or may be formed on a separate layer of the substrate as the radiating element arms  36  in antenna  30 H. 
     If desired, antennas  30  or antennas  30 H and  30 V of  FIG.  4    may be integrated within a phased antenna array.  FIG.  5    is a diagram showing one example of how antennas  30 H and  30 V may be integrated within a phased antenna array. As shown in  FIG.  5   , device  10  may include a phased antenna array  46  of stacked antennas  30 H and  30 V arranged in a rectangular grid of rows and columns. Each of the antennas in phased antenna array  46  may be formed on the same substrate. This is merely illustrative. In general, phased antenna array  46  (sometimes referred to as a phased array antenna) may include any desired number of antennas  30 V and  30 H (or non-stacked antennas  30 ) arranged in any desired pattern. Each of the antennas in phased antenna array  46  may be provided with a respective optical phase shift S ( FIGS.  2  and  3   ) that configures the antennas to collectively transmit THF signals  32  and/or receive THF signals  34  that sum to form a signal beam of THF signals in a desired beam pointing direction. The beam pointing direction may be selected to point the signal beam towards external communications equipment, towards a desired external object, away from an external object, etc. 
     Phased antenna array  46  may occupy relatively little space within device  10 . For example, each antenna  30 V/ 30 H may have a length  48  (e.g., as measured from the end of one radiating element arm to the opposing end of the opposite radiating element arm). Length  48  may be approximately equal to one-half the wavelength of THF signals  32  and  34 . For example, length  48  may be as small as 0.5 mm or less. Each UTC-PD  42  in phased antenna array  46  may occupy a lateral area of 100 square microns or less. This may allow phased antenna array  46  to occupy very little area within device  10 , thereby allowing the phased antenna array to be integrated within different portions of device  10  while still allowing other space for device components. The examples of  FIGS.  2 - 5    are merely illustrative and, in general, each antenna may have any desired antenna radiating element architecture. 
       FIG.  6    is a circuit diagram showing how a given antenna  30  and signal path  28  ( FIG.  1   ) may be used to both transmit THF signals  32  and receive THF signals  34  based on optical local oscillator signals. In the example of  FIG.  6   , UTC PD  42  converts received THF signals  34  into intermediate frequency signals SIGIF that are then converted to the optical domain for recovering the wireless data from the received THF signals. 
     As shown in  FIG.  6   , wireless circuitry  24  may include transceiver circuitry  26  coupled to antenna  30  over signal path  28  (e.g., an optical signal path sometimes referred to herein as optical signal path  28 ). UTC PD  42  may be coupled between the radiating element arm(s)  36  of antenna  30  and signal path  28 . Transceiver circuitry  26  may include optical components  68 , amplifier circuitry such as power amplifier  76 , and digital-to-analog converter (DAC)  74 . Optical components  68  may include an optical receiver such as optical receiver  72  and optical local oscillator (LO) light sources (emitters)  70 . LO light sources  70  may include two or more light sources such as laser light sources, laser diodes, optical phase locked loops, or other optical emitters that emit light (e.g., optical local oscillator signals LO 1  and LO 2 ) at respective wavelengths. If desired, LO light sources  70  may include a single light source and may include optical components for splitting the light emitted by the light source into different wavelengths. Signal path  28  may be coupled to optical components  68  over optical path  66 . Optical path  66  may include one or more optical fibers and/or waveguides. 
     Signal path  28  may include an optical splitter such as optical splitter (OS)  54 , optical paths such as optical path  64  and optical path  62 , an optical combiner such as optical combiner (OC)  52 , and optical path  40 . Optical path  62  may be an optical fiber or waveguide. Optical path  64  may be an optical fiber or waveguide. Optical splitter  54  may have a first (e.g., input) port coupled to optical path  66 , a second (e.g., output) port coupled to optical path  62 , and a third (e.g., output) port coupled to optical path  64 . Optical path  64  may couple optical splitter  54  to a first (e.g., input) port of optical combiner  52 . Optical path  62  may couple optical splitter  54  to a second (e.g., input) port of optical combiner  52 . Optical combiner  52  may have a third (e.g., output) port coupled to optical path  40 . 
     An optical phase shifter such as optical phase shifter  80  may be (optically) interposed on or along optical path  64 . An optical modulator such as optical modulator  56  may be (optically) interposed on or along optical path  62 . Optical modulator  56  may be, for example, a Mach-Zehnder modulator (MZM) and may therefore sometimes be referred to herein as MZM  56 . MZM  56  includes a first optical arm (branch)  60  and a second optical arm (branch)  58  interposed in parallel along optical path  62 . Propagating optical local oscillator signal LO 2  along arms  60  and  58  of MZM  56  may, in the presence of a voltage signal applied to one or both arms, allow different optical phase shifts to be imparted on each arm before recombining the signal at the output of the MZM (e.g., where optical phase modulations produced on the arms are converted to intensity modulations at the output of MZM  56 ). When the voltage applied to MZM  56  includes wireless data, MZM  56  may modulate the wireless data onto optical local oscillator signal LO 2 . If desired, the phase shifting performed at MZM  56  may be used to perform beam forming/steering in addition to or instead of optical phase shifter  80 . MZM  56  may receive one or more bias voltages W BIAS  (sometimes referred to herein as bias signals W BIAS ) applied to one or both of arms  58  and  60 . Control circuitry  14  ( FIG.  1   ) may provide bias voltage W BIAS  with different magnitudes to place MZM  56  into different operating modes (e.g., operating modes that suppress optical carrier signals, operating modes that do not suppress optical carrier signals, etc.). 
     Intermediate frequency signal path  44  may couple UTC PD  42  to MZM  56  (e.g., arm  60 ). An amplifier such as low noise amplifier  82  may be interposed on intermediate frequency signal path  44 . Intermediate frequency signal path  44  may be used to pass intermediate frequency signals SIGIF from UTC PD  42  to MZM  56 . DAC  74  may have an input coupled to up-conversion circuitry, modulator circuitry, and/or baseband circuitry in a transmitter of transceiver circuitry  26 . DAC  74  may receive digital data to transmit over antenna  30  and may convert the digital data to the analog domain (e.g., as data DAT). DAC  74  may have an output coupled to transmit data path  78 . Transmit data path  78  may couple DAC  74  to MZM  56  (e.g., arm  60 ). Each of the components along signal path  28  may allow the same antenna  30  to both transmit THF signals  32  and receive THF signals  34  (e.g., using the same components along signal path  28 ), thereby minimizing space and resource consumption within device  10 . 
     LO light sources  70  may produce (emit) optical local oscillator signals LO 1  and LO 2  (e.g., at different wavelengths that are separated by the wavelength of THF signals  32 / 34 ). Optical components  68  may include lenses, waveguides, optical couplers, optical fibers, and/or other optical components that direct the emitted optical local oscillator signals LO 1  and LO 2  towards optical splitter  54  via optical path  66 . Optical splitter  54  may split the optical signals on optical path  66  (e.g., by wavelength) to output optical local oscillator signal LO 1  onto optical path  64  while outputting optical local oscillator signal LO 2  onto optical path  62 . 
     Control circuitry  14  ( FIG.  1   ) may provide phase control signals CTRL to optical phase shifter  80 . Phase control signals CTRL may control optical phase shifter  80  to apply optical phase shift S to the optical local oscillator signal LO 1  on optical path  64 . Phase shift S may be selected to steer a signal beam of THF signals  32 / 34  in a desired pointing direction. Optical phase shifter  80  may pass the phase-shifted optical local oscillator signal LO 1  (denoted as LO 1 +S) to optical combiner  52 . Signal beam steering is performed in the optical domain (e.g., using optical phase shifter  80 ) rather than in the THF domain because there are no satisfactory phase shifting circuit components that operate at frequencies as high as the frequencies of THF signals  32  and  34 . Optical combiner  52  may receive optical local oscillator signal LO 2  over optical path  62 . Optical combiner  52  may combine optical local oscillator signals LO 1  and LO 2  onto optical path  40 , which directs the optical local oscillator signals onto UTC PD  42  for use during signal transmission or reception. 
     During transmission of THF signals  32 , DAC  74  may receive digital wireless data (e.g., data packets, frames, symbols, etc.) for transmission over THF signals  32 . DAC  74  may convert the digital wireless data to the analog domain and may output (transmit) the data onto transmit data path  78  as data DAT (e.g., for transmission via antenna  30 ). Power amplifier  76  may amplify data DAT. Transmit data path  78  may pass data DAT to MZM  56  (e.g., arm  60 ). MZM  56  may modulate data DAT onto optical local oscillator signal LO 2  to produce modulated optical local oscillator signal LO 2 ′ (e.g., an optical local oscillator signal at the frequency/wavelength of optical local oscillator signal LO 2  but that is modulated to include the data identified by data DAT). Optical combiner  52  may combine optical local oscillator signal LO 1  with modulated optical local oscillator signal LO 2 ′ at optical path  40 . 
     Optical path  40  may illuminate UTC PD  42  with (using) optical local oscillator signal LO 1  (e.g., with the phase shift S applied by optical phase shifter  80 ) and modulated optical local oscillator signal LO 2 ′. Control circuitry  14  ( FIG.  1   ) may apply a control signal V BIAS  to UTC PD  42  that configures antenna  30  for the transmission of THF signals  32 . UTC PD  42  may convert optical local oscillator signal LO 1  and modulated optical local oscillator signal LO 2 ′ into antenna currents on radiating element arm(s)  36  at the frequency of THF signals  32  (e.g., while programmed for transmission using control signal V BIAS ). The antenna currents on radiating element arm(s)  36  may radiate THF signals  32 . The frequency of THF signals  32  is given by the difference in frequency between optical local oscillator signal LO 1  and modulated optical local oscillator signal LO 2 ′. Control signals V BIAS  may control UTC PD  42  to preserve the modulation from modulated optical local oscillator signal LO 2 ′ in the radiated THF signals  32 . External equipment that receives THF signals  32  will thereby be able to extract data DAT from the THF signals  32  transmitted by antenna  30 . 
     During reception of THF signals  34 , MZM  56  does not modulate any data onto optical local oscillator signal LO 2 . Optical path  40  therefore illuminates UTC PD  42  with optical local oscillator signal LO 1  (e.g., with phase shift S) and optical local oscillator signal LO 2 . Control circuitry  14  ( FIG.  1   ) may apply a control signal V BIAS  (e.g., a bias voltage) to UTC PD  42  that configures antenna  30  for the receipt of THF signals  32 . UTC PD  42  may use optical local oscillator signals LO 1  and LO 2  to convert the received THF signals  34  into intermediate frequency signals SIGIF output onto intermediate frequency signal path  44  (e.g., while programmed for reception using bias voltage V BIAS ). Intermediate frequency signals SIGIF may include the modulated data from the received THF signals  34 . Low noise amplifier  82  may amplify intermediate frequency signals SIGIF, which are then provided to MZM  56  (e.g., arm  60 ). MZM  56  may convert intermediate frequency signals SIGIF to the optical domain as optical signals LOrx (e.g., by modulating the data in intermediate frequency signals SIGIF onto one of the optical local oscillator signals) and may pass the optical signals to optical receiver  72  in optical components  68 , as shown by arrow  63  (e.g., via optical paths  62  and  66  or other optical paths). Control circuitry  14  ( FIG.  1   ) may use optical receiver  72  to convert optical signals LOrx to other formats and to recover (demodulate) the data carried by THF signals  34  from the optical signals. In this way, the same antenna  30  and signal path  28  may be used for both the transmission and reception of THF signals while also performing beam steering operations. 
     The example of  FIG.  6    in which intermediate frequency signals SIGIF are converted to the optical domain is merely illustrative. If desired, transceiver circuitry  26  may receive and demodulate intermediate frequency signals SIGIF without first passing the signals to the optical domain. For example, transceiver circuitry  26  may include an analog-to-digital converter (ADC), intermediate frequency signal path  44  may be coupled to an input of the ADC rather than to MZM  56 , and the ADC may convert intermediate frequency signals SIGIF to the digital domain. As another example, intermediate frequency signal path  44  may be omitted and control signals V BIAS  may control UTC PD  42  to directly sample THF signals  34  with optical local oscillator signals LO 1  and LO 2  to the optical domain. As an example, UTC PD  42  may use the received THF signals  34  and control signals V BIAS  to produce an optical signal on optical path  40 . The optical signal may have an optical carrier with sidebands that are separated from the optical carrier by a fixed frequency offset (e.g., 30-100 GHz, 60 GHz, 50-70 GHz, 10-100 GHz, etc.). The sidebands may be used to carry the modulated data from the received THF signals  34 . Signal path  28  may direct (propagate) the optical signal produced by UTC PD  42  to optical receiver  72  in optical components  68  (e.g., via optical paths  40 ,  64 ,  62 ,  66 ,  63 , and/or other optical paths). Control circuitry  14  ( FIG.  1   ) may use optical receiver  72  to convert the optical signal to other formats and to recover (demodulate) the data carried by THF signals  34  from the optical signal (e.g., from the sidebands of the optical signal). 
       FIG.  7    is a circuit diagram showing one example of how multiple antennas  30  may be integrated into a phased antenna array  88  that conveys THF signals over a corresponding signal beam. In the example of  FIG.  7   , MZMs  56 , intermediate frequency signal paths  44 , data paths  78 , and optical receiver  72  of  FIG.  6    have been omitted for the sake of clarity. Each of the antennas in phased antenna array  88  may alternatively sample received THF signals directly into the optical domain or may pass intermediate frequency signals SIGIF to ADCs in transceiver circuitry  26 . 
     As shown in  FIG.  7   , phased antenna array  88  includes N antennas  30  such as a first antenna  30 - 0 , a second antenna  30 - 1 , and an Nth antenna  30 -(N−1). Each of the antennas  30  in phased antenna array  88  may be coupled to optical components  68  via a respective optical signal path (e.g., optical signal path  28  of  FIG.  6   ). Each of the N signal paths may include a respective optical combiner  52  coupled to the UTC PD  42  of the corresponding antenna  30  (e.g., the UTC PD  42  in antenna  30 - 0  may be coupled to optical combiner  52 - 0 , the UTC PD  42  in antenna  30 - 1  may be coupled to optical combiner  52 - 1 , the UTC PD  42  in antenna  30 -(N−1) may be coupled to optical combiner  52 -(N−1), etc.). Each of the N signal paths may also include a respective optical path  62  and a respective optical path  64  coupled to the corresponding optical combiner  52  (e.g., optical paths  64 - 0  and  62 - 0  may be coupled to optical combiner  52 - 0 , optical paths  64 - 1  and  62 - 1  may be coupled to optical combiner  52 - 1 , optical paths  64 -(N−1) and  62 -(N−1) may be coupled to optical combiner  52 -(N−1), etc.). 
     Optical components  68  may include LO light sources  70  such as a first LO light source  70 A and a second LO light source  70 B. The optical signal paths for each of the antennas  30  in phased antenna array  88  may share one or more optical splitters  54  such as a first optical splitter  54 A and a second optical splitter  54 B. LO light source  70 A may generate (e.g., produce, emit, transmit, etc.) first optical local oscillator signal LO 1  and may provide first optical local oscillator signal LO 1  to optical splitter  54 A via optical path  66 A. Optical splitter  54 A may distribute first optical local oscillator signal LO 1  to each of the UTC PDs  42  in phased antenna array  88  over optical paths  64  (e.g., optical paths  64 - 0 ,  64 - 1 ,  64 -(N−1), etc.). Similarly, LO light source  70 B may generate (e.g., produce, emit, transmit, etc.) second optical local oscillator signal LO 2  and may provide second optical local oscillator signal LO 2  to optical splitter  54 B via optical path  66 B. Optical splitter  54 B may distribute second optical local oscillator signal LO 2  to each of the UTC PDs  42  in phased antenna array  88  over optical paths  62  (e.g., optical paths  62 - 0 ,  62 - 1 ,  62 -(N−1), etc.). 
     A respective optical phase shifter  80  may be interposed along (on) each optical path  64  (e.g., a first optical phase shifter  80 - 0  may be interposed along optical path  64 - 0 , a second optical phase shifter  80 - 1  may be interposed along optical path  64 - 1 , an Nth optical phase shifter  80 -(N−1) may be interposed along optical path  64 -(N−1), etc.). Each optical phase shifter  80  may receive a control signal CTRL that controls the phase S provided to optical local oscillator signal LO 1  by that optical phase shifter (e.g., first optical phase shifter  80 - 0  may impart an optical phase shift of zero degrees/radians to the optical local oscillator signal LO 1  provided to antenna  30 - 0 , second optical phase shifter  80 - 1  may impart an optical phase shift of Δϕ to the optical local oscillator signal LO 1  provided to antenna  30 - 1 , Nth optical phase shifter  80 -(N−1) may impart an optical phase shift of (N−1)Δϕ to the optical local oscillator signal LO 1  provided to antenna  30 -(N−1), etc.). By adjusting the phase S imparted by each of the N optical phase shifters  80 , control circuitry  14  ( FIG.  1   ) may control each of the antennas  30  in phased antenna array  88  to transmit THF signals  32  and/or to receive THF signals  34  within a formed signal beam  83 . Signal beam  83  may be oriented in a particular beam pointing direction (angle)  84  (e.g., the direction of peak gain of signal beam  83 ). The THF signals conveyed by phased antenna array  88  may have wavefronts  86  that are orthogonal to beam pointing direction  84 . Control circuitry  14  may adjust beam pointing direction  84  over time to point towards external communications equipment or an external object or to point away from external objects, as examples. 
     Phased antenna array  88  may be operable in an active mode in which the array transmits and/or receives THF signals using optical local oscillator signals LO 1  and LO 2  (e.g., using phase shifts provided to each antenna element to steer signal beam  83 ). If desired, phased antenna array  88  may also be operable in a passive mode in which the array does not transmit or receive THF signals. Instead, in the passive mode, phased antenna array  88  may be configured to form a passive reflector that reflects THF signals or other electromagnetic waves incident upon device  10 . In the passive mode, the UTC PDs  42  in phased antenna array  88  are not illuminated by optical local oscillator signals LO 1  and LO 2  and transceiver circuitry  26  performs no modulation/demodulation, mixing, filtering, detection, modulation, and/or amplifying of the incident THF signals. 
     Antenna radiating element arm(s)  36  and UTC PD  42  ( FIG.  6   ) may sometimes be referred to herein collectively as access point (AP)  45  (e.g., a THF access point). In some implementations, a single access point  45  is used to communicate with a single external device (e.g., another device such as device  10 , a wireless base station or access point, or other wireless (THF) communications equipment). If desired, transceiver  26  may use multiple access points distributed across one or more locations to concurrently communicate with one or more external devices over one or more streams of wireless signals (e.g., THF signals  32  and  34  of  FIG.  1   ). 
     To maximize the overall data rate and/or flexibility of THF communications performed using device  10 , wireless circuitry  24  may convey THF signals using multiple electromagnetic polarizations such as a first polarization and a second polarization that is different from (e.g., orthogonal to) the first polarization. Each polarization may, for example, be used to concurrently convey respective streams of wireless data.  FIG.  8    is a diagram showing one example of how device  10  may convey THF signals using multiple electromagnetic polarizations. 
     As shown in  FIG.  8   , wireless communications system  95  (sometimes referred to herein as THF system  95 , wireless system  95 , communications system  95 , or simply as system  95 ) may include one or more access points such as access point  45 . Access point  45  may include at least one dual-polarization antenna  94 . Dual-polarization antenna  94  may, for example, include overlapping antennas  30 V and  30 H having orthogonal radiating element arms (e.g., bow tie antennas as shown in  FIG.  4   ). Antennas  30 V and  3011  may be fed using respective UTC PDs  42  in access point  45 , for example. Antenna  3011  may transmit THF signals with a first polarization such as THF signals  32 H whereas antenna  30 V transmits THF signals with a second polarization orthogonal to the first polarization such as THF signals  32 V. 
     In the example of  FIG.  8   , THF signals  32 H have a first linear polarization (e.g., a horizontal polarization) whereas THF signals  32 V have a second linear polarization orthogonal to the first linear polarization (e.g., a vertical polarization). This is merely illustrative. In general, THF signals  32 H and  32 V may have any desired polarizations. THF signals  32 H and  32 V need not be linearly polarized and, if desired, other polarizations such as circular or elliptical polarizations may be used. While THF signals  3211  and antenna  30 H are sometimes referred to herein as “horizontally polarized” or are otherwise denoted using the letter H, the angle of the corresponding electric field may be oriented in any desired direction. Similarly, while THF signals  32 V and antenna  30 V are sometimes referred to herein as “vertically polarized” or are otherwise denoted using the letter V, the angle of the corresponding electric field may be oriented in any desired direction (e.g., orthogonal to the direction of the “horizontally polarized” signals). 
     Wireless communications system  95  may also include a centralized optical controller such as central optical controller  90 . Central optical controller  90  may sometimes also be referred to herein as central office  90 , central chip  90 , optical controller  90 , or optical processor  90 . Central optical controller  90  may include control circuitry such as control circuitry  14  of  FIG.  1   . The components of wireless circuitry  24  of  FIG.  6    may be distributed between access points  45  and central optical controller  90  of  FIG.  8   . For example, central optical controller  90  may include transceiver  26  and signal path  28  of  FIG.  6   . Central optical controller  90  may be communicably coupled to access point  45  over an optical signal path such as optical path  92 . Optical path  92  may include one or more optical fibers and/or waveguides. 
     Central optical controller  90  may be co-located with access point  45  or may be disposed at a location separated from access point  45 . For example, central optical controller  90 , optical path  92 , and access point  45  may all be enclosed within an electronic device housing such as housing  102  (e.g., a housing such as housing  12  of  FIG.  1   ). When configured in this way, central optical controller  90 , optical path  92 , and access point  45  may all form components of a corresponding device  10 . As another example, central optical controller  90  may be enclosed within a first housing such as housing  96  (e.g., a housing such as housing  12  of  FIG.  1   ) whereas access point  45  is enclosed within a second housing  100  (e.g., a housing such as housing  12  of  FIG.  1   ). When configured in this way, central optical controller  90  may be located within a first device  10  whereas access point  45  is located within a second device  10 . 
     In other words, wireless communications system  95  may be located within a single device  10  or may be distributed across multiple devices  10 . In examples where the components of wireless communications system  95  are located within a single device  10 , access point  45  may be separated from or co-located with central optical controller  90  within the device and optical path  92  may have a length on the order of inches, centimeters, or meters. In examples where the components of wireless communications system  95  are located within different devices  10 , central optical controller  90  may be located in the same room or a different room of the same building or a different building as access point  45  or may be located in a different geographic region from access point  45  (e.g., optical path  92  may be as long as a few km, dozens of km, hundreds of km, or thousands of km in length). If desired, optical path  92  may include multiple optical fibers that are coupled together in series using optical couplers, optical boosters/amplifiers, optical relays, etc. 
     Central optical controller  90  may generate optical signals (e.g., optical local oscillator signals) for access point  45 . Central optical controller  90  may transmit the optical signals over optical path  92 . Access point  45  may transmit wireless signals  3211  and  32 V using the optical signals. Access point  45  may transmit THF signals  32 H and  32 V to one or more external devices such as external device  98 . The UTC PD  42  coupled to antenna  30 V may transmit THF signals  32 V using a pair of optical signals received over optical path  92  (e.g., where the frequency of THF signals  32 V is given by the difference in frequency between the pair of optical signals). Similarly, the UTC PD  42  coupled to antenna  30 H may transmit THF signals  32 H using a pair of optical signals received over optical path  92  (e.g., where the frequency of THF signals  32 H is given by the difference in frequency between the pair of optical signals). External device  98  may be another device such as device  10 , a wireless base station or access point, or other wireless (THF) communications equipment, for example. While  FIG.  8    illustrates the transmission of THF signals  32 H and  32 V, wireless communications system  95  may additionally or alternatively receive THF signals  34  ( FIG.  1   ) from external device  98  in one or more (e.g., orthogonal) polarizations. 
     The fiber and radio resources in wireless communications system  95  should be as tightly coupled as possible. Coupling the fiber and radio parameters (e.g., bandwidth, modulation order, polarization, symbol rate, etc.) as much as possible may minimize the resources required at access point  45 , where only minimal processing of the optical signals from central optical controller  90  towards THF frequencies would be required. In a simplest case, an optical polarization plane may be frequency shifted to a linearly polarized THF signal. This may avoid any demodulation and remodulation within access point  45 . As a consequence, the optical fiber channel and the THF (radio) transmission channel may be viewed as a combined overall channel. 
     Conveying THF signals with multiple polarizations can raise many challenges to efficient wireless communications between external device  98  and wireless communications system  95 . For example, external device  98  may be able to coherently demodulate the separate streams of wireless data in THF signals  32 H and  32 V when the antennas on external device  98  for conveying THF signals in each polarization are aligned with the antennas on wireless communications system  95  that transmitted THF signals  32 H and  32 V, when external device  98  does not move or rotate with respect to wireless communications system  95 , and when wireless communications system  95  does not move or rotate with respect to external device  98 . 
     In practice, wireless communications system  95  and/or external device  98  will move and/or rotate frequently over time. Wireless communications system  95  may not have knowledge at any given moment of the precise orientation and position of external device  98  with respect to wireless communications system  95 . Similarly, external device  98  may not have knowledge at any given moment of the precise orientation and position of wireless communications system  95 . As such, if care is not taken, it can be difficult for external device  98  to demodulate the different wireless data streams in THF signals  32 H and  32 V properly and coherently (e.g., due to the misalignment and/or changing alignment between wireless communications system  95  and external device  98 ). 
     In addition, polarization dispersion in the optical fibers of wireless communications system  95  (e.g., optical path  92 ) and radio-frequency transmission/polarization impairments (e.g., in access point  45 ) can further limit the ability of external device  98  to coherently demodulate the different wireless data streams in THF signals  32 H and  32 V. To mitigate these issues, wireless communications system  95  and external device  98  may use THF signals  32 H and  32 V to estimate and mitigate the misalignment between external device  98  and wireless communications system  95  and to mitigate transmission impairments within wireless communications system  95 . 
     To further illustrate the transmission impairments within wireless communications system  95 , consider a system model for the most dominant error signals in a dual-polarization coherent optical fiber system. In this model, the transmission impairments generally include chromatic dispersion (CD) and polarization effects such as polarization-mode dispersion (PMD). PMD is modeled as polarization rotation, represented by a unitary matrix and differential group delay (DGD) between the orthogonal polarization tributaries. Amplified spontaneous emission (ASE) from erbium-doped fiber amplifiers may be modeled as additive white Gaussian noise (AWGN) for the optical field. Nonlinear distortions induced through transmission over the optical fiber and transmit (TX) in-phase quadrature-phase (I/Q) imbalance are disregarded. The transmitted signal of each polarization is multiplexed and transmitted over the optical fiber (e.g., optical path  92 ). The optical linear field impairments can be modeled using equation 1.
 
 H (ω)= J·D (ω)· C ( z ,ω)  (1)
 
In equation 1, ω is angular frequency, z is propagation distance, J is a Jones matrix representation of a random polarization rotation with random phase shifts between transmit and receiver axes (e.g., as given by equation 2), D(ω) is a matrix that represents the PMD-induced differential group delay between both polarization waves, whose values generally range between 1 and 100 ps (e.g., as given by equation 3), and C(z,ω) corresponds to the frequency response of chromatic dispersion (e.g., as given by equation 4).
 
     
       
         
           
             
               
                 
                   J 
                   = 
                   
                     ( 
                     
                       
                         
                           
                             cos 
                             ⁢ 
                             α 
                           
                         
                         
                           
                             
                               e 
                               
                                 
                                   - 
                                   j 
                                 
                                 ⁢ 
                                 θ 
                               
                             
                             ⁢ 
                             sin 
                             ⁢ 
                             α 
                           
                         
                       
                       
                         
                           
                             
                               - 
                               
                                 e 
                                 
                                   
                                     - 
                                     j 
                                   
                                   ⁢ 
                                   0 
                                 
                               
                             
                             ⁢ 
                             sin 
                             ⁢ 
                             α 
                           
                         
                         
                           
                             cos 
                             ⁢ 
                             α 
                           
                         
                       
                     
                     ) 
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
     In equation 2, α is the azimuth rotation angle and θ is the elevation rotation angle that can make the signal state of polarization sweep over the entire Poincaré sphere, and j is the square root of negative one. 
     
       
         
           
             
               
                 
                   
                     D 
                     ⁡ 
                     ( 
                     ω 
                     ) 
                   
                   = 
                   
                     ( 
                     
                       
                         
                           
                             e 
                             
                               j 
                               ⁢ 
                               ω 
                               ⁢ 
                               τ 
                               / 
                               2 
                             
                           
                         
                         
                           0 
                         
                       
                       
                         
                           0 
                         
                         
                           
                             e 
                             
                               
                                 - 
                                 j 
                               
                               ⁢ 
                               ω 
                               ⁢ 
                               τ 
                               / 
                               2 
                             
                           
                         
                       
                     
                     ) 
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
       
         
           
             
               
                 
                   
                     C 
                     ⁡ 
                     ( 
                     ω 
                     ) 
                   
                   = 
                   
                     
                       e 
                       
                         
                           
                             - 
                             j 
                           
                           ⁢ 
                           
                             λ 
                             2 
                           
                           ⁢ 
                           Dz 
                         
                         
                           4 
                           ⁢ 
                           π 
                           ⁢ 
                           c 
                         
                       
                     
                     ⁢ 
                     
                       ω 
                       2 
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
     In equation 4, λ is the central wavelength of the transmitted optical wave, c is the speed of light in a vacuum, and D is the fiber chromatic dispersion coefficient. Polarization dependent loss (PDL) is omitted from the model. 
     Additional transmission impairments are also considered, as the fiber-impaired signal is directly transferred to THF and experiences additional radio transmission impairments. Such impairments include misalignment (rotation) between wireless communications system  95  and external device  98 . Assuming a simplest case that only accounts for line of sign (LOS) between wireless communications system  95  and external device  98 , rotation of external device  98  (e.g., the mobile receiver) is considered in the polarization plane. In the model, the transmit polarization direction and the receiver polarization direction are each projected onto a projection plane. In the projection plane, the projected receiver polarization direction is oriented at a rotation angle α with respect to a vector in the projection plane that is orthogonal to the transmit polarization direction as projected into the projection plane (assuming that the transmitter and the receiver are arranged on the optical axis so the electric field is perpendicular to the axis). This results in a Jones matrix M(ϑ) as given by equation 5. 
     
       
         
           
             
               
                 
                   
                     M 
                     ⁡ 
                     ( 
                     ϑ 
                     ) 
                   
                   = 
                   
                     ( 
                     
                       
                         
                           
                             cos 
                             ⁢ 
                             ϑ 
                           
                         
                         
                           
                             sin 
                             ⁢ 
                             ϑ 
                           
                         
                       
                       
                         
                           
                             
                               - 
                               sin 
                             
                             ⁢ 
                             ϑ 
                           
                         
                         
                           
                             cos 
                             ⁢ 
                             ϑ 
                           
                         
                       
                     
                     ) 
                   
                 
               
               
                 
                   ( 
                   5 
                   ) 
                 
               
             
           
         
       
     
     Transmission impairments associated with UTC PD  42  and the antennas that convey THF signals  32 H and  32 V are generally on the order of −20 dB from one polarization to another. As such, these impairments can be omitted from the model. Given each of these impairments, optical fiber and THF polarization impairments can be modeled/represented more simply using the matrix H(ω) given by equation 6, which characterizes the overall impairment response associated with transmission of THF signals  32 H and  32 V by wireless communications system  95  to external device  98  (e.g., taking into account impairments in the optical domain at wireless communications system  95 , in the THF domain at wireless communications system  95 , and in the THF domain as given by the rotation/misalignment of wireless communications system  95  with respect to external device  98 ).
 
 H (ω)= J·D (ω)· C ( z ,ω)· M (ϑ)  (6)
 
     The transmitting device (e.g., wireless communications system  95 ) and the receiving device (e.g., external device  98 ) may be configured to mitigate these transmission impairments to maximize the communications efficiency of the system.  FIG.  9    is a circuit diagram showing one example of how central optical controller  90  of  FIG.  8    may transmit optical signals to access point  45 . 
     As shown in  FIG.  9   , central optical controller  90  may include LO light sources such as light sources  120  and  122  (e.g., light sources such as light sources  70  of  FIG.  6    or light sources  70 A and  70 B of  FIG.  7   ). Light sources  120  and  122  may include light-emitting diodes or laser light sources, as examples. Light source  120  may be coupled to a first optical combiner (OC)  130  over optical path  118  (e.g., one or more optical fibers, waveguides, etc.). Light source  120  may also be coupled to a second optical combiner (OC)  136  over optical path  116  (e.g., one or more optical fibers, waveguides, etc.). Light source  122  may also be coupled to optical combiners  130  and  136  over optical path  134  (e.g., one or more optical fibers, waveguides, etc.). 
     Central optical controller  90  may include an optical modulator such as optical modulator  124  interposed along optical path  118 . Optical modulator  124  may, for example, include a first optical branch  126  and a second optical branch  128  and may include MZMs  58  interposed on each optical branch. Optical modulator  124  may receive wireless data DAT for transmission. Wireless data DAT may include, for example, I/Q data (e.g., where in-phase data DAT(I) is provided to the MZM  58  on optical branch  126  and quadrature-phase data DAT(Q) is provided to the MZM  58  on optical branch  128 ). The output of optical combiners  130  and  136  may be coupled to the input of polarization combiner  132 . The output of polarization combiner  132  may be coupled to optical path  92 . 
     During wireless transmission, light source  120  may emit light (e.g., LO signals) on optical paths  118  and  116  at an optical frequency such as frequency f_ 0 . Optical structures in central optical controller  90  may configure the light at frequency f_ 0  emitted onto optical path  118  to exhibit a first polarization (e.g., a vertical linear polarization V) and may configure the light at frequency f_ 0  emitted onto optical path  116  to exhibit a second polarization that is different from (e.g., orthogonal to) the first polarization (e.g., a horizontal linear polarization H). 
     Central optical controller  90  may use optical modulator  124  to modulate a signal (e.g., wireless data DAT) onto the vertically polarized light at frequency f_ 0  emitted onto optical path  118  by light source  120  to produce (generate) a vertically (V) polarized modulated signal such as modulated signal S(V) (e.g., a modulated signal on a carrier at frequency f_ 0 ). The light emitted onto optical path  116  is un-modulated and is therefore referred to herein as a horizontally (H) polarized unmodulated carrier C(H). At the same time, light source  122  may emit an optical local oscillator signal at frequency f_LO onto optical path  134 . 
     Optical combiner  130  may combine the optical local oscillator signal at frequency f_LO with modulated signal S(V) to produce vertically polarized combined signal S′(V) (e.g., a dual tone signal pair where one tone is modulated with wireless data DAT). Graph  110  of  FIG.  9    plots vertically polarized combined signal S′(V) in power (P) as a function of frequency (F). As shown by graph  110 , vertically polarized combined signal S′(V) includes an unmodulated spectral line (peak) at frequency f_LO (e.g., from the optical local oscillator signal emitted by light source  122 ) and a modulated signal (e.g., as produced by optical modulator  124 ) on a carrier at frequency f_ 0  (e.g., as produced by light source  120 ). Frequency f_LO is separated from frequency f_ 0  by frequency gap  114 . Frequency gap  114  corresponds to the frequency of the wireless signals conveyed by access point  45  ( FIG.  8   ) using vertically polarized combined signal S′(V). Frequency gap  114  may be, for example 25-1000 GHz. 
     Similarly, optical combiner  136  may combine the optical local oscillator at frequency f_LO with unmodulated carrier C(H) to produce horizontally polarized combined signal C′(H) (e.g., a dual tone signal pair where both tones are unmodulated). Graph  112  of  FIG.  9    plots horizontally polarized combined signal C′(H). As shown by graph  112 , horizontally polarized combined signal C′(H) includes a first unmodulated spectral line (peak) at frequency f_LO (e.g., from the optical local oscillator signal emitted by light source  122 ) and a second unmodulated spectral line (peak) at frequency f_ 0  (e.g., as produced by light source  120 ). Polarization combiner  132  may combine the optical signals of each polarization (e.g., may combine the vertically polarized combined signal S′(V) and the horizontally polarized combined signal C′(H)) and may output the optical signals on optical path  92 . 
     Access point  45  ( FIG.  8   ) may receive combined signals S′(V) and C′(H) over optical path  92 . Access point  45  may include a polarization splitter that separates combined signal S′(V) from combined signal C′(H). Access point  45  may include a first UTC PD  42  coupled to antenna  30 V in dual-polarization antenna  94  ( FIG.  8   ) that is illuminated using combined signal S′(V) to cause antenna  30 V to convey vertically polarized THF signals (e.g., THF signals  32 V of  FIG.  8   ). Access point  45  may include a second UTC PD  42  coupled to antenna  30 H in dual-polarization antenna  94  ( FIG.  8   ) that is illuminated using combined signal C′(H) to cause antenna  30 H to convey horizontally polarized THF signals (e.g., THF signals  32 H of  FIG.  8   ). If desired, access point  45  may include multiple dual-polarization antennas  94  (e.g., in a phased antenna array as shown in  FIG.  7   ) to convey THF signals  32 H and  32 V in signal beams oriented in a selected beam pointing direction. The example of  FIG.  9    is merely illustrative. If desired, central optical controller  90  may use other transmit signal definitions to produce optical signals for controlling antennas  30 V and  30 H in access point  45  to convey THF signals of any desired polarizations. 
       FIG.  10    is a circuit diagram showing one example of how external device  98  of  FIG.  8    may receive and process the THF signals  32 V and  32 H transmitted by wireless communications system  95  (e.g., while mitigating transmission impairments associated with communicating using THF signals of different polarizations). In the example of  FIG.  10   , external device  98  is an electronic device such as device  10 . 
     As shown in  FIG.  10   , device  10  may include a dual-polarization antenna such as dual-polarization antenna  140 . While only a single dual-polarization antenna  140  is illustrated in  FIG.  10    for the sake of clarity, device  10  may include a phased antenna array of dual-polarization antennas  140  if desired. Dual-polarization antenna  140  may include antenna  32 V for conveying vertically polarized THF signals and antenna  32 H for conveying horizontally polarized THF signals. This is merely illustrative and, in general, dual-polarization antenna  140  may convey THF signals with any desired polarizations. 
     Dual-polarization antenna  140  may be coupled to a first photodiode such as photodiode  144  and to a second photodiode such as photodiode  142  (e.g., UTC photodiodes such as UTC photodiode  42  of  FIG.  6   ). Device  10  may include a light source  146  (e.g., a light source in light sources  70  of  FIG.  6   ) that illuminates photodiodes  142  and  144  using optical local oscillator signal LO 3 . Light source  146  may include, for example, a vertical cavity surface emitting laser (VCSEL). Optical local oscillator signal LO 3  may be at a carrier frequency of combined signals S′(V) and C′(H) and thus THF signals  32 H/ 32 V (e.g., frequency f_ 0  of light source  120  in central optical controller  90  of  FIG.  9   ). 
     Antenna  32 V may receive THF signals  32 V from wireless communications system  95  ( FIG.  8   ) as vertically polarized receive signals RXTHF(V) (e.g., at a frequency equal to frequency gap  114  of  FIG.  9   ). Antenna  32 V may pass vertically polarized receive signals RXTHF(V) to photodiode  142 . If desired, one or more amplifiers (e.g., low noise amplifiers) may amplify vertically polarized receive signals RXTHF(V) prior to transmission to photodiode  144 . Similarly, antenna  32 H may receive THF signals  32 H from wireless communications system  95  as horizontally polarized receive signals RXTHF(H) (e.g., at a frequency equal to frequency gap  114  of  FIG.  9   ). Antenna  32 H may pass horizontally polarized receive signals RXTHF(H) to photodiode  144 . If desired, one or more amplifiers (e.g., low noise amplifiers) may amplify horizontally polarized receive signals RXTHF(H) prior to transmission to photodiode  142 . 
     Photodiode  144  may use optical local oscillator signal LO 3  to upconvert horizontally polarized receive signals RXTHF(H) to an optical frequency as horizontally polarized optical signals RXOPT(H). Similarly, photodiode  142  may use optical local oscillator signal LO 3  to upconvert vertically polarized receive signals RXTHF(V) to an optical frequency as vertically polarized optical signals RXOPT(V). In other words, photodiodes  144  and  142  may convert the received signals from the THF domain to the optical domain. 
     As shown in  FIG.  10   , the transceiver circuitry in device  10  may include a Stokes vector receiver such as Stokes vector receiver (SVR)  160 . SVR  160  may have two or more input ports (terminals) such as input ports  152 . SVR  160  may also have three or more output ports (terminals) such as output ports  154 . A first input port  152  of SVR  160  may be coupled to photodiode  144  over optical path  150  (e.g., one or more optical fibers and/or waveguides). A second input port  152  of SVR  160  may be coupled to photodiode  142  over optical path  148  (e.g., one or more optical fibers and/or waveguides). Photodiode  144  may emit horizontally polarized optical signals RXOPT(H) on optical path  150  and SVR  160  may receive horizontally polarized optical signals RXOPT(H) over its first input port  152 . Photodiode  142  may emit vertically polarized optical signals RXOPT(V) on optical path  148  and SVR  160  may receive vertically polarized optical signals RXOPT(V) over its second input port  152 . 
     SVR  160  may include a first optical coupler such as optical coupler  158  and a second optical coupler such as optical coupler  162  (e.g., optical splitters and optionally optical combiners). Optical coupler  158  may be coupled to the first input port  152 . Optical coupler  162  may be coupled to the second input port  152 . SVR  160  may also include a downconverting mixing device such as mixing device  156 . Mixing device  156  may be, for example, a 90-degree optical hybrid mixing device such as a photonic homodyne receiver (e.g., a direct conversion homodyne mixing device). 
     SVR  160  may include a set of photodetectors (e.g., balanced photodetectors) such as photodiodes  164 ,  166 , and  168 . Photodiode  164  may be optically coupled to optical coupler  158  and optical coupler  162 . Photodiode  168  may be optically coupled to the output of mixing device  156 . Photodiode  166  may be optically coupled to the output of mixing device  166 . Photodiodes  164 ,  166 , and  168  may also be coupled to respective output ports  154  of SVR  160 . Mixing device  156  may have inputs coupled to optical couplers  158  and  162 . 
     During signal reception, optical coupler  158  may provide horizontally polarized optical signal RXOPT(H) to photodiode  164  and the input of mixing device  156 . Optical coupler  162  may provide vertically polarized optical signal RXOPT(V) to photodiode  164  and the input of mixing device  156 . Mixing device  156  may perform homodyne mixing on horizontally polarized optical signal RXOPT(H) and vertically polarized optical signal RXOPT(V) that downconverts the signals and may provide (output) optical signals to photodiodes  166  and  168 . 
     SVR  160  may output a Stokes vector SV on output ports  154 . Each output port  154  may output a respective vector element from Stokes vector SV. For example, photodiode  164  may be illuminated using vertically polarized optical signal RXOPT(V) and horizontally polarized optical signal RXOPT(H) to produce vector element S 1  of stokes vector SV on a first output port  154  of SVR  160 . Similarly, photodiode  168  may be illuminated using first outputs of mixing device  156  to produce vector element S 2  of stokes vector SV on a second output port  154  of SVR  160  and photodiode  166  may be illuminated using second outputs of mixing device  156  to produce vector element S 3  of Stokes vector SV on a third output port  154  of SVR  160 . In other words, Stokes vector SV may be represented by the vector [S 1 , S 2 , S 3 ] T , where T is the transpose operator. This example is merely illustrative. Stokes vector SV may have more than three elements (e.g., four elements) and SVR  160  may have more than three output ports  154  (e.g., four output ports). Stokes vector SV may include single-ended or differential signals. Other SVR architectures may be used if desired. 
     The THF signals  32 H and  32 V received at device  10  may be expressed by a Jones vector J=[S, C] T , where S is the modulated signal from vertically polarized combined signal S′(V) and C is the unmodulated carrier from horizontally polarized combined signal C′(H) ( FIG.  9   ). Assuming no polarization rotation (e.g., perfect alignment) between wireless communications system  95  and device  10  of  FIG.  10   , the Jones vector would appear like the ideal Stokes Vector SV when output by SVR  160 . In other words, in the absence of polarization rotation, SVR  160  may output a Stokes vector SV as given by equation 7.
 
 SV=[S   1   ,S   2   ,S   3 ] T   =[|S|   2   −|C|   2 Re( S·C *)]  (7)
 
     In equation 7, Re( ) is a real number operator that outputs the real component of its argument and Im( ) is an imaginary number operator that outputs the imaginary component of its argument. In other words, in this ideal case, photodiode  164  in SVR  160  may output S 1  as |S| 2 −|C| 2 , photodiode  168  in SVR  160  may output S 2  as Re(S·C*), and photodiode  166  in SVR  160  may output S 3  as Im(S·C*). 
     However, in practice, there is non-zero polarization rotation between wireless communications system  95  and device  10  (e.g., device  10  and wireless communications system  95  are imperfectly aligned) and such rotation may change as wireless communications system  95  and/or device  10  moves or changes orientation. As such, control circuitry  14  ( FIG.  1   ) may measure (e.g., identify, detect, gather, generate, estimate, etc.) Stokes vector SV using SVR  160 , may identify (e.g., detect, generate, estimate, etc.) the polarization rotation between device  10  and wireless communications system  95  using the measured Stokes vector SV, and may actively compensate for the identified polarization rotation during the reception of subsequent THF signals from wireless communications system  95 . 
     Since the non-ideal signal polarization is randomly rotated in the optical fiber and wireless channels, the received optical signals RXOPT(H) and RXOPT(V) will each be an arbitrary/random mixture of the transmitted modulated signal S and the transmitted unmodulated carrier C. SVR  160  may be used to acquire the polarization rotation (PR) between device  10  and wireless communications system  95 . Unlike coherent detection, which performs PR in the Jones space, SVR  160  performs PR detection in the Stokes space. The Stokes space may be depicted by a Poincaré sphere having a random rotation of the V and H polarization planes because of fiber and wireless polarization transmission. Control circuitry  14  may identify these planes and may de-rotate the planes to align the V and H polarization planes with the S 2  and S 3  planes, respectively, in the Poincaré sphere. To recover the received signal, control circuitry  14  may identify (e.g., detect, generate, estimate, etc.) an SV rotation matrix X of the combined channel and may use the SV rotation matrix X to rotate the stokes vector SV for subsequently-received signals to align with those at the transmitter (wireless communications system  95 ). 
     If desired, wireless communications system  95  may transmit test data that allows device  10  to identify rotation matrix X at any given instant.  FIG.  11    is a flow chart of illustrative operations involved in controlling wireless communications system  95  and device  10  to identify rotation matrix X for use in performing subsequent communications while mitigating polarization rotations and other impairments between device  10  and wireless communications system  95 . Operations  172 ,  176 ,  180 , and  184  of  FIG.  11    may be performed by device  10  of  FIG.  10    (e.g., a first device  10 ). Operations  170 ,  174 ,  178 , and  182  of  FIG.  11    may be performed by wireless communications system  95  of  FIG.  9    (e.g., at least a second device  10 ). The test data transmitted by wireless communications system  95  may include a series of test data such as a series of training symbols. The training symbols may, for example, be added before each transmit signal frame in the time domain. 
     At operation  170 , wireless communications system  95  may transmit vertically polarized combined signal S′(V) and horizontally polarized combined signal C′(H) ( FIG.  9   ), where vertically polarized combined signal S′(V) includes a first training (test) symbol from a series of training (test) symbols. The training symbol may include a predetermined pattern or series of bits that are known to both device  10  and wireless communications system  95 . Wireless communications system  95  may, for example, append the first training symbol to the beginning of a first signal frame in the time domain. The first training symbol may, for example, involve the transmission of no modulated signals, thereby resulting in a Jones vector of [0, 1]. This may correspond to an expected Stokes vector SVE at device  10  of [−1,0,0] T , which is predetermined and known to device  10  (e.g., which is expected by device  10  during the scheduled transmission of the first training symbol). Equation 8 characterizes the Stokes vector SV measured by SVR  160  on device  10  in response to the first training symbol.
 
 SV=X· SVE  (8)
 
     Equation 9 expands the vectors and matrices of Equation 7 to show each element S of the Stokes vector SV measured using SVR  160  on device  10 , each element x of SV rotation matrix X, and each element of the expected Stokes vector SVE for the first training symbol. 
     
       
         
           
             
               
                 
                   
                     ( 
                     
                       
                         
                           
                             S 
                             1 
                           
                         
                       
                       
                         
                           
                             S 
                             2 
                           
                         
                       
                       
                         
                           
                             S 
                             3 
                           
                         
                       
                     
                     ) 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             
                               x 
                               11 
                             
                           
                           
                             
                               x 
                               12 
                             
                           
                           
                             
                               x 
                               13 
                             
                           
                         
                         
                           
                             
                               x 
                               21 
                             
                           
                           
                             
                               x 
                               22 
                             
                           
                           
                             
                               x 
                               23 
                             
                           
                         
                         
                           
                             
                               x 
                               31 
                             
                           
                           
                             
                               x 
                               32 
                             
                           
                           
                             
                               x 
                               33 
                             
                           
                         
                       
                       ) 
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           
                             
                               - 
                               1 
                             
                           
                         
                         
                           
                             0 
                           
                         
                         
                           
                             0 
                           
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                   ( 
                   9 
                   ) 
                 
               
             
           
         
       
     
     At operation  172 , device  10  may receive the first training symbol transmitted by wireless communications system  95  and may provide the corresponding optical signals RXOPT(H) and RXOPT(V) to SVR  160 . SVR  160  may generate Stokes vector SV based on the received first training symbol. As shown by equation 9, the first training symbol will cause the multiplication of SV rotation matrix X and expected Stokes vector [−1,0,0] T  to preserve only the first column of SV rotation matrix X (e.g., [x 11 , x 21 , x 31 ] T ) while the remaining columns are equal to zero. As such, control circuitry  14  on device  10  may identify (e.g., measure, detect, determine, generate, etc.) the first column of SV rotation matrix X by using SVR  160  to generate Stokes vector SV in response to the first training symbol received in optical signals RXOPT(H) and RXOPT(V) (e.g., where the element S 1  output by photodiode  164  is equal to −x 11 , the element S 2  output by photodiode  168  is equal to −x 21 , and the element S 3  output by photodiode  166  is equal to −x 31 ). Subsequent training symbols may be used to identify the remaining columns of SV rotation matrix X. 
     At operation  174 , wireless communications system  95  may transmit vertically polarized combined signal S′(V) and horizontally polarized combined signal C′(H) ( FIG.  9   ), where vertically polarized combined signal S′(V) includes a second training (test) symbol from the series of training (test) symbols. The power of horizontally polarized combined signal C′(H) may remain constant for the first and second training symbols. Wireless communications system  95  may, for example, append the second training symbol to the beginning of a second signal frame in the time domain. The second training symbol may, for example, involve the transmission of a real signal with a constant power that is the same as that of the carrier, thereby resulting in a Jones vector of [1, 1]. This may correspond to an expected Stokes vector SVE at device  10  of [0,1,0] T , which is predetermined and known to device  10  (e.g., which is expected by device  10  during the scheduled transmission of the second training symbol). Equation 10 characterizes the Stokes vector SV measured by SVR  160  on device  10  in response to the second training symbol. 
     
       
         
           
             
               
                 
                   
                     ( 
                     
                       
                         
                           
                             S 
                             1 
                           
                         
                       
                       
                         
                           
                             S 
                             2 
                           
                         
                       
                       
                         
                           
                             S 
                             3 
                           
                         
                       
                     
                     ) 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             
                               x 
                               11 
                             
                           
                           
                             
                               x 
                               12 
                             
                           
                           
                             
                               x 
                               13 
                             
                           
                         
                         
                           
                             
                               x 
                               21 
                             
                           
                           
                             
                               x 
                               22 
                             
                           
                           
                             
                               x 
                               23 
                             
                           
                         
                         
                           
                             
                               x 
                               31 
                             
                           
                           
                             
                               x 
                               32 
                             
                           
                           
                             
                               x 
                               33 
                             
                           
                         
                       
                       ) 
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           
                             0 
                           
                         
                         
                           
                             1 
                           
                         
                         
                           
                             0 
                           
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                   ( 
                   10 
                   ) 
                 
               
             
           
         
       
     
     At operation  176 , device  10  may receive the second training symbol transmitted by wireless communications system  95  and may provide the corresponding optical signals RXOPT(H) and RXOPT(V) to SVR  160 . SVR  160  may generate Stokes vector SV based on the received second training symbol. As shown by equation 10, the second training symbol will cause the multiplication of SV rotation matrix X and expected Stokes vector [0,1,0] T  to preserve only the second column of SV rotation matrix X (e.g., [x 12 , x 22 , x 32 ] T ) while the remaining columns are equal to zero. As such, control circuitry  14  on device  10  may identify (e.g., measure, detect, determine, generate, etc.) the second column of SV rotation matrix X by using SVR  160  to generate Stokes vector SV in response to the second training symbol received in optical signals RXOPT(H) and RXOPT(V) (e.g., where the element S 1  output by photodiode  164  is equal to x 12 , the element S 2  output by photodiode  168  is equal to x 22 , and the element S 3  output by photodiode  166  is equal to x 32 ). 
     At operation  178 , wireless communications system  95  may transmit vertically polarized combined signal S′(V) and horizontally polarized combined signal C′(H) ( FIG.  9   ), where vertically polarized combined signal S′(V) includes a third training (test) symbol from the series of training (test) symbols. The power of horizontally polarized combined signal C′(H) may remain constant between the first, second, and third training symbols. Wireless communications system  95  may, for example, append the third training symbol to the beginning of a third signal frame in the time domain. The third training symbol may, for example, be represented by a Jones vector of [j, 1]. This may correspond to an expected Stokes vector SVE at device  10  of [0,0,1] T , which is predetermined and known to device  10  (e.g., which is expected by device  10  during the scheduled transmission of the second training symbol). Equation 11 characterizes the Stokes vector SV measured by SVR  160  on device  10  in response to the third training symbol. 
     
       
         
           
             
               
                 
                   
                     ( 
                     
                       
                         
                           
                             S 
                             1 
                           
                         
                       
                       
                         
                           
                             S 
                             2 
                           
                         
                       
                       
                         
                           
                             S 
                             3 
                           
                         
                       
                     
                     ) 
                   
                   = 
                   
                     
                       ( 
                       
                         
                           
                             
                               x 
                               11 
                             
                           
                           
                             
                               x 
                               12 
                             
                           
                           
                             
                               x 
                               13 
                             
                           
                         
                         
                           
                             
                               x 
                               21 
                             
                           
                           
                             
                               x 
                               22 
                             
                           
                           
                             
                               x 
                               23 
                             
                           
                         
                         
                           
                             
                               x 
                               31 
                             
                           
                           
                             
                               x 
                               32 
                             
                           
                           
                             
                               x 
                               33 
                             
                           
                         
                       
                       ) 
                     
                     ⁢ 
                     
                       ( 
                       
                         
                           
                             0 
                           
                         
                         
                           
                             0 
                           
                         
                         
                           
                             1 
                           
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                   ( 
                   11 
                   ) 
                 
               
             
           
         
       
     
     At operation  180 , device  10  may receive the third training symbol transmitted by wireless communications system  95  and may provide the corresponding optical signals RXOPT(H) and RXOPT(V) to SVR  160 . SVR  160  may generate Stokes vector SV based on the received third training symbol. As shown by equation 11, the third training symbol will cause the multiplication of SV rotation matrix X and expected Stokes vector [0,1,0] T  to preserve only the third column of SV rotation matrix X (e.g., [x 13 , x 23 , x 33 ] T ) while the remaining columns are equal to zero. As such, control circuitry  14  on device  10  may identify (e.g., measure, detect, determine, generate, etc.) the third column of SV rotation matrix X by using SVR  160  to generate Stokes vector SV in response to the third training symbol received in optical signals RXOPT(H) and RXOPT(V) (e.g., where the element S 1  output by photodiode  164  is equal to x 13 , the element S 2  output by photodiode  168  is equal to x 23 , and the element S 3  output by photodiode  166  is equal to x 33 ). In this way, device  10  may use the three training symbols to measure the elements in each column of SV rotation matrix X. Device  10  may thereafter have knowledge of the polarization rotation between device  10  and communications system  95 . 
     At operation  182 , wireless communications system  95  may continue to transmit wireless data to device  10  using THF signals  32 H and  32 V (e.g., using vertically polarized combined signal S′(V) and horizontally polarized combined signal C′(H) of  FIG.  9   ). 
     At operation  184 , device  10  may receive the transmitted wireless data. SVR  160  on device  10  may generate Stokes vector SV using the received wireless data and may multiply Stokes vector SV (e.g., the received wireless data) by the generated SV rotation matrix X to reverse, mitigate, or compensate for the polarization rotation between device  10  and wireless communications system  95  and other related optical/wireless impairments. Multiplication of the measured Stokes vector SV by SV rotation matrix X may, for example, recover the transmitted Stokes vector SV as [|S| 2 −|C| 2 , Re(S·C*), Im(S·C*)], thereby allowing device  10  to properly receive the transmitted wireless data while optimizing communications efficiency. In other words, by combining the second and third elements of the measured Stokes vector SV, control circuitry  14  on device  10  may recover a final output that has the full phase diversity of modulated signal S, from which the input signal is fully recovered without being affected by chromatic dispersion-related fading. The nonlinearity term is grouped into the first element (component) of the measured Stokes vector SV without affecting the recovered signals derived from the second and third elements (components) of the measured Stokes vector SV. 
     Processing may subsequently loop back to operation  170  via path  186  to update the rotation matrix X over time (e.g., after a predetermined time period has elapsed, at a scheduled time, in response to a user input or application call, in response to the sensed movement and/or rotation of device  10 , etc.). The example of  FIG.  11    is merely illustrative. If desired, device  10  may transmit the identified SV rotation matrix X to wireless communications system  95  (e.g., at operation  180 ) and wireless communications system  95  may pre-compensate subsequently transmitted wireless data for the polarization rotation using SV rotation matrix X (e.g., at operation  182 ). Other methods for detecting Stokes vector SV may be used if desired. These operations may be generalized to generate Stokes Vectors SV of any desired size and to recover the elements of an SV rotation matrix X of any desired size. If desired, other polarizations may be used for THF signal transmission. Other modulation formats may be used if desired. 
     Device  10  may gather and/or use personally identifiable information. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. The optical components described herein (e.g., MZM modulator(s), waveguide(s), phase shifter(s), UTC PD(s), etc.) may be implemented in plasmonics technology if desired. 
     The methods and operations described above in connection with  FIGS.  1 - 13    (e.g., the operations of  FIGS.  10  and  13   ) may be performed by the components of device  10  using software, firmware, and/or hardware (e.g., dedicated circuitry or hardware). Software code for performing these operations may be stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) stored on one or more of the components of device  10  (e.g., storage circuitry  16  of  FIG.  1   ). The software code may sometimes be referred to as software, data, instructions, program instructions, or code. The non-transitory computer readable storage media may include drives, non-volatile memory such as non-volatile random-access memory (NVRAM), removable flash drives or other removable media, other types of random-access memory, etc. Software stored on the non-transitory computer readable storage media may be executed by processing circuitry on one or more of the components of device  10  (e.g., processing circuitry  18  of  FIG.  1   , etc.). The processing circuitry may include microprocessors, central processing units (CPUs), application-specific integrated circuits with processing circuitry, or other processing circuitry. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20220527
Publication Date: 20240409
Grant Date: 20240409
Priority Date: 20210922
Inventors: GUNZELMANN, Bertram R
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B10/6162", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B2210/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B7/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B10/40", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B10/6162", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B2210/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B10/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B10/503", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B10/532", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B10/6162", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B7/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B2210/006", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q9/065", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B2210/006", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 82899359