Method and system for controlling a modal antenna with acknowledgement - Patents.com

Abstract

An antenna system is provided. In one implementation, the antenna system may include a modal antenna operable in a plurality of different modes, each mode being associated with a different radiation pattern. The antenna system may include a tuning circuit configured to operate the modal antenna in the plurality of different modes. A transmission line may be coupled to the tuning circuit. The antenna system may further include one or more control devices. The control device may be configured to modulate a control signal onto a radio frequency (RF) signal to generate a modulated signal for communication over the transmission line to the tuning circuit. The control device may be further configured to generate an acknowledgement (ACK) signal based at least in part on the control signal.

Description

[Technical Field]

[0001] Priority claim This application claims the benefit of priority to U.S. Provisional Application No. 63 / 423,241, entitled "Method and System for Controlling a Modal Antenna with Acknowledgement," filed November 7, 2022, which is incorporated herein by reference in its entirety for all purposes.

[0002] Example aspects of the present disclosure relate to antennas. [Background technology]

[0003] Modal antennas are increasingly being used in wireless communications, for example in smartphone handsets. Such antennas generally offer improved signal quality and a compact form factor over traditional passive antennas. One modal antenna configuration involves a parasitic element configured to modify the radiation pattern associated with the driven element. In this manner, a modal antenna can be configurable into multiple different modes. Furthermore, each of the multiple modes can have a distinct radiation pattern and / or polarization. Summary of the Invention [Means for solving the problem]

[0004] Aspects and advantages of embodiments of the present disclosure will be set forth in part in the description that follows, or may be learned from the description, or may be learned by practice of the embodiments.

[0005] One example aspect of the present disclosure is directed to an antenna system including a modal antenna operable in a plurality of different modes, each of which may be associated with a different radiation pattern. The antenna system may include a tuning circuit configured to control the modal antenna to operate in each of the plurality of modes. The antenna system may include a transmission line coupled to the tuning circuit. The antenna system may include one or more control devices configured to modulate a control signal onto a radio frequency (RF) signal to generate a modulated signal for communication over the transmission line to the tuning circuit. The one or more control devices may be further configured to generate an acknowledgement (ACK) signal based at least in part on the control signal.

[0006] These and other features, aspects, and advantages of various embodiments will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain relevant principles.

[0007] Detailed descriptions of embodiments directed to those skilled in the art are set forth herein with reference to the accompanying figures. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1 illustrates one embodiment of an antenna according to an example embodiment of the present disclosure. [Figure 1B] 1B is a diagram illustrating a two-dimensional antenna radiation pattern associated with the antenna of FIG. 1A. [Figure 1C] FIG. 1B illustrates an example frequency plot of the antenna of FIG. 1A according to an example embodiment of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of an example antenna system according to an example embodiment of the present disclosure. [Figure 3] FIG. 2 is a schematic diagram of an example control circuit for an antenna system according to an example embodiment of the present disclosure. [Figure 4A]FIG. 1 illustrates a series of time alignment charts showing a simplified example of binary amplitude shift keying modulation. [Figure 4B] FIG. 1 illustrates a series of time alignment charts showing a simplified example of multi-level amplitude shift keying modulation. [Figure 5] FIG. 2 is a schematic diagram of an example tuning circuit for an antenna system according to an example embodiment of the present disclosure. [Figure 6] FIG. 2 is a schematic diagram of an example back channel modulator of an antenna system according to an example embodiment of the present disclosure. [Figure 7] FIG. 2 is a schematic diagram of an example back channel receiver of an antenna system in accordance with an example embodiment of the present disclosure. [Figure 8] FIG. 1 is a flow diagram of an example method according to an example embodiment of the present disclosure. [Figure 9] 1 illustrates an example coding scheme for an antenna system according to an example embodiment of the present disclosure. [Figure 10] 10A-10C illustrate example error detection according to example embodiments of the present disclosure. [Figure 11] 10A and 10B are diagrams illustrating examples of control of modal antennas according to example embodiments of the present disclosure. [Figure 12] FIG. 1 illustrates an example general acknowledgement of a modal antenna according to an example embodiment of the present disclosure. [Figure 13] 10A-10C illustrate example individual acknowledgments of a modal antenna according to an example embodiment of the present disclosure. [Figure 14] 10A-10C illustrate example individual acknowledgments of a modal antenna according to an example embodiment of the present disclosure. [Figure 15] FIG. 1 is a flow diagram of an example method according to an example embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Reference will now be made in detail to the embodiments, one or more examples of which are illustrated in the drawings. Each example is provided as an explanation of an embodiment, and not as a limitation of the disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments without departing from the scope or spirit of the disclosure. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Accordingly, it is intended that aspects of the disclosure cover such modifications and variations.

[0010] Example aspects of the present disclosure relate generally to the field of antenna control, for example, to controlling modal antennas configured to operate in multiple different modes.

[0011] Modal antennas are increasingly being used in wireless communications. Such antennas generally offer improved signal quality and a compact form factor over traditional passive antennas. Modal antennas can be configurable into multiple different modes, with distinct radiation patterns and / or polarization states in each different mode.

[0012] The antenna system can include a modal antenna including a driven element and a parasitic element positioned proximate to the driven element, and can include a tuning circuit configured to control an electrical characteristic associated with the parasitic element to operate the modal antenna in a plurality of different modes.

[0013] The antenna system may include a radio frequency (RF) circuit and a transmission line (e.g., a single coaxial cable) coupling the RF circuit to the modal antenna. The RF circuit may be configured to modulate a control signal onto the RF signal, e.g., using amplitude shift keying modulation or other suitable modulation, to generate a transmit signal for communication over the transmission line to a tuning circuit. The tuning circuit may be configured to demodulate the control signal such that the tuning circuit can adjust the mode of the modal antenna based at least in part on the control signal. For example, the tuning circuit may control the modal antenna to operate in a selected one of a plurality of modes based at least in part on the control signal.

[0014] In some cases, the control signal communicated by the RF circuit to the tuning circuit is unidirectional. More specifically, when the RF circuit modulates the control signal onto an RF signal for communication over a transmission path to the tuning circuit, the tuning circuit does not send an ACK (acknowledgement) or NAK (negative acknowledgement) signal back to the RF circuit to acknowledge receipt of the control signal. Thus, the RF circuit does not know whether the control signal was successfully received by the tuning circuit. The RF circuit similarly does not know the real-time configuration of the modal antenna. More specifically, the RF circuit does not know in which of multiple modes the modal antenna is operating at any given moment.

[0015] According to example aspects of the present disclosure, an antenna system may include a current-mode back channel comprising modulation-demodulation circuitry. More specifically, the antenna system may include a control device configured to generate a modulated signal for communication over a transmission path to a tuning circuit by modulating a control signal onto an RF signal. The control device may be further configured to generate an acknowledgement (ACK) signal based at least in part on the control signal received by the tuning circuit. Aspects of the present disclosure are described with reference to the ACK signal. As used herein, the ACK signal may include a negative acknowledgement (NAK) signal without departing from the scope of the present disclosure.

[0016] According to example aspects of the present disclosure, the control device can be configured to generate an ACK signal based at least in part on a control signal received by the tuning circuit. More specifically, the control device can be configured to encode a plurality of bits according to a coding scheme. For example, the coding scheme can identify a unique code for each antenna mode of a plurality of modes. In some cases, the coding scheme can identify unique codes for a general acknowledgment (General ACK) request and a plurality of individual acknowledgment (Individual ACK) requests.

[0017] In some cases, the control device may include current source circuitry and current sensing circuitry. More specifically, the control device may include a switchable current source configured to operate as a back-channel modulator and a current sensor configured to operate as a back-channel receiver. The back-channel modulator may be coupled to the tuning circuit and configured to generate an ACK signal, such as a pulsed DC current signal, based at least in part on a control signal received by the tuning circuit. The back-channel receiver may be coupled to the RF circuit and configured to monitor and / or sense the ACK signal generated by the back-channel modulator.

[0018] Systems and methods according to example embodiments of the present disclosure provide several technical effects and benefits. For example, example aspects of the present disclosure provide a readback mechanism for an antenna system. More particularly, by providing a current-mode back channel, the present disclosure provides an ACK signaling mechanism and / or a real-time indication of the configuration metrics of the antenna system. In this manner, the present disclosure can, in some cases, provide an antenna system configuration readback mechanism that operates over a transmission line. The resulting current-mode back channel can provide accurate and efficient control over the operation of modal antennas and antenna systems.

[0019] 1A illustrates one embodiment of a modal antenna 10 according to aspects of the present disclosure. The modal antenna 10 may include a circuit board 12 (e.g., including a ground plane) and an active antenna element 14 provided on the circuit board 12. A first parasitic element 15 may be positioned proximate to the active antenna element 14. For example, the first parasitic element 15 may be positioned such that a current in the first parasitic element 15 affects the radiation pattern of the active element. For example, an antenna volume may be defined between the circuit board (e.g., and ground plane) and the active antenna element 14. The first parasitic element 15 may be positioned at least partially within the antenna volume.

[0020] A first active tuning element 16 may be coupled to the first parasitic element 15. The first active tuning element 16 may be a passive or active component or series of components and may be configured to change the reactance on the first parasitic element 15 by means of a variable reactance or by means of a short circuit to ground, leading to a frequency shift of the antenna.

[0021] In some embodiments, a second parasitic element 18 may be provided adjacent to the circuit board 12 and in close proximity to the driven antenna element 14 such that current in the second parasitic element 18 affects the radiation pattern of the driven element. The second parasitic element 18 may be positioned outside the antenna volume. The driven antenna element 14 may have a width 19. The second parasitic element 18 may be spaced apart from the driven antenna element 14 by a spacing distance 21. The ratio of the width 19 of the driven antenna element 14 to the spacing distance 21 may range from about 0.2 to about 10, from about 0.5 to about 8 in some embodiments, and from about 1 to about 5 in some embodiments.

[0022] The second parasitic element 18 may further include a second active tuning element 20, which may each include one or more active and / or passive components. The second parasitic element 18 may be positioned adjacent to the driven antenna element 14 or may be positioned outside the antenna volume.

[0023] The described configurations may provide the ability to shift the radiation pattern characteristics of an excited antenna element by varying the reactance thereon. Shifting the antenna radiation pattern may be referred to as “beam steering.” In instances where the antenna radiation pattern includes a null, a similar operation may be referred to as “null steering,” since the null may be shifted to an alternative location around the antenna (e.g., to reduce interference). In some embodiments, the second active tuning element 20 may include a switch for connecting the second parasitic element to ground when “on” and for terminating the short circuit when “off.” However, it should be noted that a variable reactance on either the first or second parasitic element may further provide a variable shift in the antenna pattern or frequency response, for example, by using a variable capacitor or other variable tuning component. For example, the first active tuning element 16 and / or the second active tuning element 20 may include at least one of a variable tuning capacitor, a MEMS device, a variable tuning inductor, a switch, a variable tuning phase shifter, a field-effect transistor, or a diode.

[0024] 1B illustrates a two-dimensional antenna radiation pattern associated with the modal antenna of FIG. 1A. The radiation pattern may be shifted by controlling electrical characteristics associated with at least one of the first parasitic element 15 and the second parasitic element 18 of the modal antenna 10. For example, in some embodiments, the radiation pattern may be shifted from the first mode 22 to the second mode 24 or the third mode 26.

[0025] 1C illustrates an example frequency plot of the modal antenna of FIG. 1A according to some embodiments of the present disclosure. The frequency of the antenna can be shifted by controlling the electrical characteristics associated with at least one of the first parasitic element 15 or the second parasitic element 18 of the modal antenna 10. For example, a first frequency (f) of the antenna may be achieved when the first and second parasitic elements are switched "off," and a frequency (f) may be achieved when the second parasitic element is shorted to ground. L ) and (fH ) may be generated, and frequencies (f4; f0) may be generated when the first and second parasitic elements are each shorted to ground. It should be understood that other configurations are possible within the scope of this disclosure. For example, more or fewer parasitic elements may be utilized. The positioning of the parasitic elements may be varied to achieve additional modes that may exhibit different frequencies and / or frequency combinations.

[0026] 1A-1C depict one example modal antenna having multiple modes for purposes of illustration and explanation. Those skilled in the art will understand, using the disclosure provided herein, that other modal antennas and / or antenna configurations may be used without departing from the scope of the present disclosure. As used herein, "modal antenna" refers to an antenna capable of operating in multiple modes, where each mode is associated with a distinct radiation pattern.

[0027] 2 illustrates a schematic diagram of one embodiment of an antenna system 100 according to an example aspect of the present disclosure. The antenna system 100 may include a modal antenna 102. The modal antenna 102 may include an active element 104 and a parasitic element 106 positioned proximate to the active element 104. The modal antenna 102 may be capable of operating in a number of different modes. Each mode may be associated with a different radiation pattern, for example, as described above with reference to FIGS. 1A-1C.

[0028] A tuning circuit 108 (e.g., a receiver) may be configured to control the electrical characteristics associated with the parasitic element 106 to operate the modal antenna 102 in a plurality of different modes. The tuning circuit 108 may be configured to demodulate a control signal from the transmitted signal and control the electrical characteristics of the parasitic element 106 based on a control instruction associated with the control signal, as described in more detail with reference to, for example, FIGS. 4 and 5.

[0029] A tunable component 110 may be coupled to the parasitic element 106. The tuning circuit 108 may be configured to control the tunable component 110 to change the electrical connectivity of the parasitic element 106 with a voltage or current source or sink, such as connecting the parasitic element 106 to ground.

[0030] A radio frequency circuit 112 (e.g., a transmitter) may be configured to transmit an RF signal to the driven element 104 of the modal antenna 102. For example, a transmission line 114 may couple the radio frequency circuit 112 to the modal antenna 102. In some embodiments, the transmission line 114 may be a single coaxial cable. The radio frequency circuit 112 may be configured to amplify or otherwise generate an RF signal, which is transmitted (as a component of a transmit signal) to the driven element 104 of the modal antenna 102 through the transmission line 114.

[0031] In some embodiments, the radio frequency circuit 112 may include a front-end module 116 and / or a control circuit 118. The front-end module 116 may be configured to generate and / or amplify an RF signal to be transmitted to the driven element 104. The control circuit 118 may be configured to modulate a control signal onto the RF signal using amplitude shift keying modulation to generate the transmit signal, for example, as described in more detail below with reference to FIGS.

[0032] The transmission line 114 may be coupled to various components (e.g., using bias tee circuits) configured to assist in combining and / or separating signals occupying various frequency bands. For example, a first bias tee circuit 120 may couple the transmission line 114 to the front-end module 116 and the control circuit 118. The first bias tee circuit 120 may include a capacitor 122 coupling the front-end module 116 to the transmission line 114 and an inductor 124 coupling the transmission line 114 to the control circuit 118. A second bias tee circuit 126 may couple the transmission line 114 to the driven element 104 and the tuning circuit 108. The second bias tee circuit 126 may include a capacitor 128 coupling the driven element 104 to the transmission line 114 and an inductor 130 coupling the tuning circuit 108 to the transmission line 114.

[0033] The front-end module 116 may transmit the RF signal through a capacitor 122 of the first bias tee circuit 120. The control circuit 118 may modulate the control signal onto the RF signal through an inductor 124 of the first bias tee circuit 120 to generate the control signal on the transmission line 114.

[0034] The tuning circuit 108 (e.g., a receiver) may be configured to demodulate the control signal and extract clock information associated with the transmitter. For example, the tuning circuit 108 may demodulate the control signal from the transmit signal via the inductor 130 of the second bias tee circuit 126. The RF signal component of the transmit signal may be transmitted to the driven element 104 of the modal antenna 102 via the capacitor 128 of the second bias tee circuit 126.

[0035] In some embodiments, the antenna system 100 may further include a control device 133 (e.g., a back-channel modulator). As described in more detail below with reference to FIG. 6, the control device 133 can be any suitable current source, such as a switchable current source. In some embodiments, the control device 133 can be positioned between the second bias tee circuit 126 and the tuning circuit 108. For example, the control device 133 can be positioned between and coupled to the inductor 130 and the tuning circuit 108. As described in more detail below with reference to FIGS. 8-14, the control device 133 can be configured to generate an acknowledgement (ACK) signal and transmit the ACK signal to the radio frequency circuit 112 over the transmission line 114.

[0036] In some embodiments, antenna system 100 may further include a control device 135 (e.g., a back-channel receiver). As described in more detail below with reference to FIG. 7, control device 135 can be any suitable current sensing device, such as a high-side current sensing circuit. In some embodiments, control device 135 can be positioned between first bias tee circuit 120 and control circuit 118. For example, control device 135 can be positioned between and coupled to inductor 124 and control circuit 118. As described in more detail below with reference to FIG. 15, control device 135 can be configured to sense and decode an acknowledgement (ACK) signal generated by control device 133.

[0037] In some embodiments, the antenna system 100 may include a first circuit board 129 and a second circuit board 131 that is physically separate from the first circuit board 129. The radio frequency circuit 112 and the control device 135 may be provided on the first circuit board 129. An antenna circuit comprising at least one of the tuning circuit 108 or the modal antenna 102 may be provided on the second circuit board 131. In some embodiments, the control device 133 may also be provided on the second circuit board 131. This may allow the radio frequency circuit 112 to be physically separated from the tuning circuit 108 and / or the modal antenna 102 without utilizing multiple transmission paths or adversely affecting the operation of the antenna system 100.

[0038] In some embodiments, the RF signal may be defined within a first frequency band. The control signal may be defined within a second frequency band that is distinct from the first frequency band. For example, the first frequency band may range from about 500 MHz to about 50 GHz, in some embodiments from about 1 GHz to about 25 GHz, and in some embodiments from about 2 GHz to about 7 GHz, e.g., about 5 GHz. The second frequency band may range from about 10 MHz to about 1 GHz, in some embodiments from about 20 MHz to about 800 MHz, in some embodiments from about 30 MHz to about 500 MHz, and in some embodiments from about 50 MHz to about 250 MHz, e.g., about 100 MHz.

[0039] 3 illustrates a schematic diagram of one embodiment of the control circuit 118 of the antenna system 100 illustrated in FIG. 2. The control circuit 118 may include a processor 132. The processor 132 may be configured to generate or receive control instructions to change the mode of the modal antenna 102 (illustrated in FIG. 2) or otherwise adjust the orientation or frequency of the radiation pattern of the modal antenna 102. For example, the processor 132 may receive control instructions from another processor (represented by a host in FIG. 3) and generate data describing the instructions (data in FIG. 3). N(represented by ). The data may have any suitable bit depth. For example, in some embodiments, the data may be in binary format. In other embodiments, the data may be in hexadecimal format, decimal format, etc. As described in more detail below, the data may be encoded with a coding scheme that increases error detection according to example embodiments of the present disclosure.

[0040] The control circuit 118 may also include a carrier signal source 134. In some embodiments, the carrier signal source 134 may be configured to generate a carrier signal that includes a sine wave, which may have a substantially constant frequency. In other embodiments, the carrier signal may be or include any suitable signal. For example, in some embodiments, the carrier signal may be or include any suitable repeating pattern and is not limited to being a sine wave or having a substantially constant frequency.

[0041] The control circuit 118 modulates the output of the processor onto a carrier signal to generate a control signal (TX CH in FIG. 3). N 3 ) that may describe control instructions. N 4. For example, modulator 136 may be configured to scale the amplitude of a carrier signal from carrier signal source 134 to generate the control signal, for example, by performing amplitude shift keying modulation (e.g., on-off keying modulation), as described in more detail below with reference to FIG. 4. Modulator 136 may also include an amplifier 140 and a bias tee circuit 142.

[0042] FIG. 4A illustrates a series of time-aligned charts 400 representing a simplified example of binary amplitude shift keying modulation. A binary signal 401 may alternate between a first voltage level 402 and a second voltage level 404 in a manner that describes a binary data set. The binary signal 401 may correspond to a simplified example of an output of the processor 132, which may include data describing control instructions, for example, as described above with reference to FIG. 3 . The amplitude shift keying modulation may include representing the binary signal 401 by representing the first voltage level 402 as a sinusoidal signal 406 having a varying amplitude. For example, the sinusoidal signal 406 may have a first amplitude 408 that represents the first voltage level 402 of the binary signal 401. The sinusoidal signal 406 may have a second amplitude 410 that represents the second voltage level 404 of the binary signal 401.

[0043] FIG. 4B illustrates another series of time-aligned charts 420 depicting a simplified example of multi-level amplitude shift keying modulation. Multi-level amplitude shift keying modulation may include representing a data signal having a bit depth of three or more. In other words, the data signal may be "m-level," where m represents an integer greater than or equal to three. The multi-level signal 440 may switch between multiple voltage levels 452, 454, 456, and 458 in a manner that describes a data set having a bit depth of three or more. The voltage levels 452, 454, 456, and 458 of the multi-level signal 440 may be represented as a sinusoidal signal 430 having varying amplitudes. For example, each of the voltage levels 452, 454, 456, and 458 of the multi-level signal 440 may be associated with a respective amplitude 462, 464, 466, and 468 of the sinusoidal signal 430. Multi-valued signal 440 may correspond to a simplified example of an output of processor 132, which may include data describing control instructions, for example as described above with reference to FIG.

[0044] As indicated above, in some embodiments, the receiver (e.g., tuning circuit 108) may be configured to extract clock information from the transmitted signal. The receiver may be configured to synchronize its operation (e.g., controlling electrical characteristics associated with parasitic element 106 to operate modal antenna 102 in multiple different modes) with the operation of the transmitter (e.g., radio frequency circuit 112) based on the extracted clock information. For example, in some embodiments, the receiver may lack a clock source that is separate from the transmitter's clock source (e.g., carrier signal source 134 associated with control circuit 118). In other embodiments, the receiver may include an unused clock source. Instead, the receiver may rely on the extracted clock information associated with the clock source of the transmitted signal.

[0045] In some embodiments, the control signal may include a data frame that includes a training portion 470. A tuning circuit (e.g., a receiver) may be configured to recognize the training portion 470 within the data frame to identify at least one of the beginning or end of the data frame. For example, with reference to FIG. 4B, the vertical dotted lines in the plot of the multi-level signal 440 may represent divisions between bits. For example, as illustrated in FIG. 4B, one byte may include eight bits.

[0046] The data frame may also include a data portion 472 that contains or describes data (e.g., control instructions for adjusting the mode of a modal antenna, as described above with reference to FIGS. 1A-1C). The receiver may be configured to locate the data portion 472 within the data frame based on the identified location of the training portion 470 within the data frame. The training portion 470 may include a predetermined series of bits and / or have a predetermined location within the data frame. For example, as illustrated in FIGS. 4A and 4B, the training portion 470 may include a set of consecutive bits at the beginning of the data (e.g., the first three bits). The data portion 472 may include another set of consecutive bits (e.g., the next five bits after the training portion 470). The training portion 470 may have any suitable bit depth, length, and location within the data frame. Similarly, the data portion 472 may have any suitable bit depth, length, and location within the data frame. The data frame may have any suitable bit depth and length. By way of example, in some embodiments, a data frame may include multiple bytes. A data frame may include a single training portion 470, or multiple training portions 470 may be provided within a data frame. Thus, the training portions 470 may be configured to provide a reference point for the receiver so that the receiver can locate the start of a data frame, the end of a data frame, or the location of a data portion 472 within a data frame.

[0047] In some embodiments, the transmitter may be configured to modulate a clock signal onto the RF signal using multi-level amplitude shift keying. The receiver may be configured to demodulate the control signal and extract from the RF signal a clock signal including clock information associated with the transmitter. For example, with reference to FIG. 4B , the clock signal may be or include at least a portion of the training portion 470. The receiver may be configured to identify the location of the data portion 472 within the data frame based on the clock information associated with the transmitter.

[0048] In some embodiments, the transmitter may be configured to modulate a clock signal onto the RF signal using a first set of amplitude levels and modulate a control signal onto the RF signal using a second set of amplitude levels that includes at least one amplitude level that is distinct from the first set of amplitude levels. As an example, in one embodiment, the clock signal may be at least partially represented or described within the training portion 470. Referring to FIG. 4B , in a simple example, the first set of amplitude levels may correspond to amplitudes 462, 464 of the sinusoidal signal 430 and voltage levels 452, 454 of the multi-level signal 440. The second set of amplitude levels may correspond to amplitudes 466, 468 of the sinusoidal signal 430 and voltage levels 456, 458 of the multi-level signal 440. In this example, the first set of amplitude levels (associated with the control signal) are completely distinct from the second set of amplitude levels (associated with the clock signal). However, in other embodiments, the first and second sets of amplitude levels may partially overlap (e.g., may include one or more of the same amplitude levels), which may enable the receiver to more accurately and reliably locate and extract the clock signal and information from the RF signal.

[0049] 5 illustrates a schematic diagram of one embodiment of a tuning circuit 500 (e.g., a receiver), for example, corresponding to tuning circuit 108 described above with reference to FIG. 2, in accordance with aspects of the present disclosure. Tuning circuit 500 may include a demodulator 502 and a bias 504. Demodulator 502 may include a bias tee circuit 506 coupled to bias 504 and a multiplexer 507 coupled to transmission line 114 (illustrated in FIG. 2).

[0050] The tuning circuit 500 may also include a low-pass filter 508 configured to filter at least one frequency band. For example, the low-pass filter 508 may be configured to filter at least one frequency band higher than the frequency of the carrier signal frequency. As such, the low-pass filter 508 may isolate or relatively increase the strength of the carrier signal frequency. The demodulator 502 may also include a diode 510, such as a Zener diode. The diode 510 may be coupled to a logic circuit 512 configured to interpret control instructions associated with (e.g., contained within) the control signal.

[0051] Logic circuit 512 (e.g., a processor, ASIC, etc. configured to execute computer-readable instructions to perform logical operations) may be configured to control the operation of switch 514 based on control instructions associated with (e.g., contained within) the control signal. Switch 514 may be coupled to ground and configured to switch between one or more of a plurality of states. For example, switch 514 may be configured to selectively couple output 516 of switch 514 to ground or otherwise vary the electrical connectivity of output 516 to control an electrical characteristic associated with parasitic element 106 (illustrated in FIG. 2 ) and operate the modal antenna in a plurality of different modes. For example, switch 514 may be configured to adjust the operation of tunable component 110 (illustrated in FIG. 2 ) to change the electrical connectivity of parasitic element 106 with a source or sink (e.g., a voltage source / sink or a current source / sink). For example, switch 514 may be configured to selectively couple parasitic element 106 to ground.

[0052] In some embodiments, the tuning circuit 500 (e.g., a receiver) may not have a clock source. For example, the receiver may be configured to demodulate the control signal and extract clock information associated with the transmitter. The receiver may synchronize its operation with the transmitter based on the extracted clock information instead of utilizing a clock source separate from the receiver's clock source. For example, the logic circuit 512 of the tuning circuit 500 (e.g., a receiver) may not utilize a clock source separate from the transmitter's clock source (e.g., the carrier signal source 134 associated with the control circuit 118). Instead, the tuning circuit 500 (e.g., a receiver) may synchronize its operation with the control circuit 118 (e.g., a transmitter) based on the extracted clock information. For example, the tuning circuit 500 may be configured to demodulate the control signal. For example, logic circuit 512 may be configured to sample the received signal (e.g., from diode 510), extract clock information from the received signal, and then use the clock information to locate data portions within the received signal, e.g., as described above with reference to Figures 4A and 4B.

[0053] In some embodiments, the receiver may be configured to sample the transmit signal at a frequency significantly greater than the signal frequency associated with the transmit frequency. For example, the signal frequency associated with the transmit frequency may correspond to the frequency of a carrier signal (e.g., the sine wave signal 430 described above with reference to FIG. 4B). As another example, the signal frequency associated with the transmit frequency may correspond to the frequency at which the amplitude of the carrier signal (e.g., the sine wave signal 430) changes or switches between amplitude levels.

[0054] The receiver may be configured to sample the transmit signal at a sampling frequency sufficiently greater than the signal frequency associated with the transmit frequency so that changes in the amplitude of the carrier signal can be detected with sufficient accuracy to demodulate the control and / or clock signals from the transmit signal and decipher the data (e.g., instructions) contained therein. For example, the receiver may be configured to sample the transmit signal at a sampling frequency that is at least the Nyquist rate or frequency of the signal frequency. In some embodiments, the receiver may be configured to sample the transmit signal at a sampling frequency that is a predetermined multiple of the signal frequency associated with the transmit frequency. For example, in some embodiments, the frequency may be 2 to 1,000 times greater than the signal frequency, in some embodiments 5 to 500 times greater, and in some embodiments 10 to 100 times greater.

[0055] 6 illustrates a schematic diagram of an example embodiment of a back-channel modulator 600 (e.g., a switchable current source), e.g., corresponding to control device 133 described above with reference to FIG. 2, according to an example aspect of the present disclosure. Back-channel modulator 600 may include a switching device 602 and a current source 604.

[0056] The switching device 602 can be used to control the operation of the back channel modulator 600. More specifically, the switching device 602 can be used to selectively couple a current source 604 to the tuning circuit 108 (shown in FIG. 2 ) and the second bias tee circuit 126 (shown in FIG. 2 ). For example, the switching device 602 can be a single-pole, single-throw (SPST) switch movable between a first position 606 and a second position 608. When the switching device 602 is in the first position 606, the current source 604 is not coupled to the tuning circuit 108 and the second bias tee circuit 126. However, when the switching device 602 is in the second position 608, the current source 604 can be triggered to send a current pulse to the control device 135 (shown in FIG. 2 ).

[0057] The switching device 602 may include, for example, a transistor, an integrated circuit, an on / off circuit breaker such as a toggle switch, a relay (mechanical, electrical, or digital), a double-pole single-throw (DPST) switch, or other switching device. Aspects of the present disclosure are described with reference to an SPST switch for purposes of illustration and explanation. Those skilled in the art will understand, using the disclosure provided herein, that aspects of the present disclosure can be implemented using any suitable switching device without departing from the scope of the present disclosure.

[0058] FIG. 7 illustrates a schematic diagram of an example embodiment of a back-channel receiver 700 (e.g., a current sensor), eg, corresponding to control device 135 described above with reference to FIG. 2, according to an example aspect of the present disclosure.

[0059] The back-channel receiver 700 may include an operational amplifier 702 having a non-inverting input 704, an inverting input 706, and an output 708. The back-channel receiver 700 may also include a current-sensing device, such as a current-sensing resistor 710, positioned between and coupling the non-inverting input 704 and the inverting input 706. The back-channel receiver 700 may also include a load 712 positioned between the current-sensing resistor 710 and ground.

[0060] In example embodiments, back-channel receiver 700 can be operated as a current sensor. For example, back-channel receiver 700 can be configured to sense current pulses generated by back-channel modulator 600 (shown in FIG. 6) and provide a signal indicative of the current to control circuit 118 (shown in FIG. 2). More specifically, operational amplifier 702 can be configured to monitor and / or sense the current flowing into inductor 124 and provide a signal indicative of the received current pulse to control circuit 118 via output 708.

[0061] The back-channel receiver 700 can be any device suitable for sensing the current pulses generated by the back-channel modulator 600. Aspects of the present disclosure are described with reference to the high-side current sensing circuit in FIG. 7 for purposes of illustration and explanation. Those skilled in the art will understand, using the disclosure provided herein, that aspects of the present disclosure can be implemented using any suitable current sensing device without departing from the scope of the present disclosure.

[0062] 6 and 7, as described in more detail below with reference to method 800 of FIG. 8, in some implementations, tuning circuit 108 (shown in FIG. 2) can trigger back-channel modulator 600 to send a pulsed DC current signal in response to an acknowledgement (ACK) request received from radio frequency circuit 112 (shown in FIG. 2). Antenna system 100 can be configured to facilitate transmission of the pulsed DC current signal to back-channel receiver 700 via transmission path 114 (shown in FIG. 2). Back-channel receiver 700 can be configured to sense the pulsed DC current signal generated by back-channel modulator 600. In some implementations, back-channel receiver 700 can be configured to decode the pulsed DC current signal received from back-channel modulator 600 as an acknowledgement (ACK) signal.

[0063] FIG. 8 depicts a flow diagram of an example method 800 according to an example embodiment of the present disclosure. FIG. 8 depicts steps performed in a particular order for purposes of illustration and explanation. Those skilled in the art will understand, using the disclosure provided herein, that various steps of any of the methods described herein can be omitted, expanded, performed simultaneously, rearranged, and / or modified in various ways without departing from the scope of the present disclosure. Additionally, various steps (not illustrated) can be performed without departing from the scope of the present disclosure. Additionally, method 800 is generally described with reference to antenna system 100, described above with reference to FIG. 2. However, it should be understood that aspects of the present method 800 can find application in any suitable antenna system, including modal antennas.

[0064] The method 800 may include, at 802, modulating a control signal onto an RF signal to generate a transmit signal. For example, the control signal may include control instructions to change a mode of a modal antenna or otherwise adjust the orientation or frequency of a radiation pattern of the modal antenna. For example, the radio frequency circuitry 112 may include a control circuit 118 configured to modulate the control signal onto an RF signal to generate a transmit signal, e.g., as described above with reference to Figures 3, 4A, and 4B.

[0065] The control signal can be implemented in one or more frames. Each frame can include multiple bits. The frame can identify a selected mode among multiple modes for operation of the modal antenna. The control signal (e.g., command) can be encoded with a coding scheme that increases error detection by the tuning circuit. For example, the coding scheme can assign a unique code to each mode among multiple modes.

[0066] In some embodiments, the unique code can be encoded using 11 or more bits (e.g., 11 bits, 21 bits). The unique code for each mode can differ from the unique code for each other mode in the plurality of modes by at least 2 bits, such as by at least 3 bits, such as by at least 4 bits, such as by at least 5 bits, such as by at least 6 bits, such as by at least 7 bits, such as by at least 8 bits, etc. As a result, the unique code for each mode in the plurality of modes is separated by a significant distance (e.g., in terms of a binary code) from the unique code for each of the other antenna modes.

[0067] For example, FIG. 9 depicts an example coding scheme 900 according to an example embodiment of the present disclosure. The coding scheme 900 assigns a unique 11-bit code to each of four different antenna modes: Mode 0, Mode 1, Mode 2, and Mode 3. More specifically, code 902 is assigned to Mode 0. Code 904 is assigned to Mode 1. Code 906 is assigned to Mode 2. Code 908 is assigned to Mode 3. The coding scheme 900 similarly assigns a unique 11-bit code to a general acknowledgment request and each of four different mode-specific acknowledgment requests: General ACK, Mode 0 ACK, Mode 1 ACK, Mode 2 ACK, and Mode 3 ACK. More specifically, code 910 is assigned to the General ACK. Code 912 is assigned to the Mode 0 ACK. Code 914 is assigned to the Mode 1 ACK. Code 916 is assigned to the Mode 2 ACK. Code 918 is assigned to the Mode 3 ACK.

[0068] Aspects of the present disclosure are described with reference to four modes for purposes of illustration and explanation. Those skilled in the art will understand, using the disclosure provided herein, that any number of modes can be used, such as eight modes, sixteen modes, thirty-two modes, etc., without departing from the scope of the present disclosure. Additionally, aspects of the present disclosure are described with reference to unique codes implemented in binary format. Those skilled in the art will understand, using the disclosure provided herein, that other numerical schemes can be used (e.g., decimal, hexadecimal) without departing from the scope of the present disclosure.

[0069] 9, codes 902, 904, 906, 908, 910, 912, 914, 916, and 918 in coding scheme 900 differ from each other by at least two bits, such as by at least five bits. As a result, codes 902, 904, 906, 908, 910, 912, 914, 916, and 918 are separated from each other by a significant distance. This facilitates error detection, as described below.

[0070] 8, the method 800 may include, at 804, communicating a transmit signal to the tuning circuit via a single coaxial transmission line. For example, as described above with reference to FIG. 2, the radio frequency circuit 112 may include a front-end module 116 that may communicate an RF signal through the capacitor 122 of the first bias tee circuit 120, through the transmission line 114, and through the capacitor 128 of the second bias tee circuit 126 to the driven element 104 of the modal antenna 102. The control circuit 118 may modulate a control signal onto the RF signal through the inductor 124 of the first bias tee circuit 120, through the transmission line 114, and through the inductor 130 of the second bias tee circuit 126 to the tuning circuit 108.

[0071] The method 800 may include, at 806, demodulating the control signal with a tuning circuit. For example, as described above with reference to FIGS. 2 and 5, the tuning circuit 108, 500 may be configured to demodulate the control signal from the transmit signal via the inductor 130 of the second bias tee circuit 126. The tuning circuit 108, 500 may also be configured to filter and / or amplify the control signal to isolate or relatively increase the strength of a carrier signal frequency associated with the carrier signal. The logic circuit 512 may be configured to obtain and / or interpret control instructions associated with (e.g., included in) the control signal.

[0072] For example, at 808, the method 800 may include processing a frame of control signals (e.g., bits in the control signals) for error detection. For example, at 810, the logic circuit 512 may process a plurality of bits in the frame to determine whether a unique code matches a unique code in the coding scheme 900.

[0073] 10 depicts logic circuit 512 of an example tuning circuit processing a plurality of bits 920. The plurality of bits 920 differs from each of the plurality of bits associated with unique codes 902, 904, 906, 908, 910, 912, 914, 916, and 918. However, because the plurality of bits 920 does not match a unique code in coding scheme 900, logic circuit 512 can easily detect the error. This error detection is facilitated by the fact that the unique codes in the coding scheme are separated by a significant distance, reducing errors that match other unique codes.

[0074] 8, if an error is detected at 810 (e.g., the unique code does not match any of the unique codes in coding scheme 900), method 800 can proceed to 812, where the tuning circuit maintains the current mode of the antenna. In other words, the tuning circuit does not respond to the erroneous control signal and maintains the modal antenna in its current mode.

[0075] 8 , if no errors are present at (810), the method 800 may proceed to (814) to determine whether the unique code matches a unique code assigned to a mode in the coding scheme 900. For example, the tuning circuit may determine whether the unique code matches any of the unique codes 902, 904, 906, and 908.

[0076] 8 , if the unique code matches a unique code assigned to a mode in coding scheme 900 at (814), method 800 may proceed to (816) to control the modal antenna according to the selected mode identified by the unique code. For example, method 800 may include controlling an electrical characteristic associated with a parasitic element of the modal antenna based at least in part on the control signal to control the modal antenna in the selected mode.

[0077] As an illustrative example, FIG. 11 depicts logic circuit 512 of an example tuning circuit processing a plurality of bits in a frame received over a transmission path. Logic circuit 512 processes the bits and can determine that the bits match unique code 904. As described above with respect to coding scheme 900 of FIG. 9, unique code 904 is associated with Mode 1. As a result, logic circuit 512 can determine that the control signal has a control instruction to operate the modal antenna in Mode 1. For example, as described above with reference to FIG. 5, logic circuit 512 can control switch 514 to change an electrical characteristic associated with parasitic element 106 (illustrated in FIG. 2) such that the modal antenna operates in Mode 1.

[0078] 8 , if at (814) the unique code does not match a unique code assigned to a mode in coding scheme 900, method 800 may proceed to (818) to determine whether the unique code matches a unique code assigned to a general acknowledgment request in coding scheme 900. For example, a tuning circuit may determine whether the unique code matches unique code 910.

[0079] 8 , if the unique code matches the unique code 910 assigned to the general acknowledgement request (818), then the method 800 may proceed to (820) sending an acknowledgement (ACK) signal via the back channel modulator. For example, the method 800 may include the control device 133 (e.g., the back channel modulator 600) sending the ACK signal to the radio frequency circuit 112 over the transmission path 114.

[0080] As an illustrative example, FIG. 12 depicts logic circuit 512 of an example tuning circuit processing multiple bits in a frame received over a transmission path. Logic circuit 512 processes the bits and can determine that the bits match a unique code 910. As described above with respect to coding scheme 900 of FIG. 9, unique code 910 is associated with a general ACK request. As a result, logic circuit 512 can determine that the control signal comprises a control instruction comprising a general acknowledgment request. In response to determining that the control signal comprises an instruction comprising a general acknowledgment request, control device 133 (e.g., back-channel modulator 600) can send an ACK signal to radio frequency circuit 112 over transmission path 114. For example, as described above with reference to FIG. 6, when logic circuit 512 determines that the control signal comprises an instruction comprising a general ACK request, switching device 602 can be triggered to move from first position 606 to second position 608, resulting in current source 604 being coupled to tuning circuit 108 and second bias tee circuit 126. Additionally, the current source 604 may then be triggered to send an ACK signal (eg, a current pulse) over the transmission line 114 to the radio frequency circuit 112 .

[0081] 8, if there is no error at 810, the unique code does not match the unique code assigned to the mode at 814, and the unique code does not match the unique code assigned to the general acknowledgement request at 818, then the unique code is associated with a mode-specific acknowledgement request, and method 800 may proceed at 822. At 822, method 800 may include comparing the mode associated with the unique code to the current mode of configuration of the modal antenna (e.g., the mode associated with the mode-specific acknowledgement request). For example, at 824, logic circuit 512 may determine whether the current operating mode of the modal antenna matches the mode identified by the unique code associated with the mode-specific acknowledgement request.

[0082] 8 , if the current operating mode of the modal antenna matches the mode identified by the unique code associated with the mode-specific acknowledgment request (824), method 800 may proceed to (826) to send an ACK signal via the back channel modulator. As described above with respect to the general acknowledgment request, method 800 may include control device 133 (e.g., back channel modulator 600) sending the ACK signal to radio frequency circuit 112 over transmission path 114.

[0083] As an illustrative example, FIG. 13 depicts logic circuitry 512 of an example tuning circuit processing a plurality of bits in a frame received over transmission path 114. Logic circuitry 512 may process the bits and determine that the bits match a unique code 914. As described above with respect to coding scheme 900 of FIG. 9, unique code 914 is associated with a Mode 1 ACK request. Logic circuitry 512 may also determine that the modal antenna is currently operating in Mode 1. In response to determining that the modal antenna is operating in the same mode as indicated by the modal acknowledgment request, control device 133 (e.g., back-channel modulator 600) may send an ACK signal over transmission path 114 to radio frequency circuitry 112. For example, as described above with reference to FIGS. 5 and 6, when logic circuitry 512 determines that the control signal comprises a Mode 1 ACK request, logic circuitry 512 may control switch 514 such that the modal antenna is operating in Mode 1. In response to determining that the modal antenna is operating in the same mode as indicated by code 914, the control device 133 (e.g., back channel modulator 600) may be triggered to send an ACK signal to the radio frequency circuit 112 over the transmission path 114 in a manner similar to that described above with reference to FIG. 12.

[0084] 8, if at 824 the current operating mode of the modal antenna does not match the mode identified by the unique code associated with the mode-specific acknowledgment request, method 800 may proceed to 828, where control device 133 (e.g., back-channel modulator 600) does not respond to the mode-specific acknowledgment request associated with the unique code, and the tuning circuitry maintains the current mode of the antenna. In other words, the tuning circuitry does not respond to control signals that include the mode-specific acknowledgment request, and maintains the modal antenna in its current operating mode.

[0085] As an illustrative example, FIG. 14 depicts logic circuit 512 of an example tuning circuit processing multiple bits in a frame received over transmission path 114. Logic circuit 512 processes the bits and can determine that the bits match unique code 918. As described above with respect to coding scheme 900 of FIG. 9, unique code 918 is associated with a Mode 3 ACK request. Logic circuit 512 can also determine that the modal antenna is currently operating in Mode 1. In response to determining that the modal antenna is not operating in the same mode as indicated by the modal acknowledgment request, control device 133 (e.g., back-channel modulator 600) does not send an ACK signal to radio frequency circuit 112, and the tuning circuit maintains the modal antenna in Mode 1. For example, as described above with reference to FIG. 6, switching device 602 can remain in first position 606 such that current source 604 is not coupled to tuning circuit 108 and second bias tee circuit 126. Therefore, the current source 604 is not triggered to send an ACK signal (e.g., a current pulse) to the radio frequency circuit 112 through the transmission path 114. Additionally, the logic circuit 512 can control the switch 514 such that the operating mode of the modal antenna remains unchanged.

[0086] FIG. 15 depicts a flow diagram of an example method 1500 according to an example embodiment of the present disclosure. FIG. 15 depicts steps performed in a particular order for purposes of illustration and explanation. Those skilled in the art will understand, using the disclosure provided herein, that various steps of any of the methods described herein can be omitted, expanded, performed simultaneously, rearranged, and / or modified in various ways without departing from the scope of the present disclosure. Additionally, various steps (not illustrated) can be performed without departing from the scope of the present disclosure. Additionally, method 1500 is generally described with reference to antenna system 100, described above with reference to FIG. 2. However, it should be understood that aspects of method 1500 can find application in any suitable antenna system, including modal antennas.

[0087] The method 1500 may include, at 1502, sending a general acknowledgement (General ACK) request frame. For example, the General ACK request frame may include instructions for generating an acknowledgement (ACK) signal in response to receiving the General ACK request frame. More particularly, the General ACK request frame may include a unique code (e.g., code 910) assigned to the General ACK request according to a coding scheme, such as coding scheme 900 as described above with reference to FIG. 9.

[0088] 15, method 1500 may proceed to (1504) to determine whether an ACK signal was successfully received in response to the general ACK request frame sent at (1502). For example, with reference to FIGS. 6 and 7, if back-channel receiver 700 receives a pulsed DC current signal (i.e., an ACK signal) from back-channel modulator 600 in response to sending the general ACK request frame at (1502), the general ACK request frame was successfully received. However, if back-channel receiver 700 does not receive a pulsed DC current signal (i.e., an ACK signal) from back-channel modulator 600 in response to sending the general ACK request frame at (1502), the general ACK request frame was not successfully received.

[0089] 15, if the general ACK request frame sent at 1502 is not successfully received at 1504, the method 1500 may proceed to 1506 and determine that a modal antenna control channel error exists. In response to determining that a modal antenna control channel error exists, the method 1500 may perform a re-initialization process and return to 1502.

[0090] 15 , at 1504, if the general ACK request frame sent at 1502 is successfully received, method 1500 may proceed at 1508. At 1508, method 1500 may include sending an individual acknowledgment (individual ACK) request frame. For example, the individual ACK request frame may include instructions for generating an acknowledgment (ACK) signal in response to receiving the individual ACK request frame. More specifically, the individual ACK request frame may include a unique code (e.g., code 912, 914, 916, 918) assigned to the mode-specific ACK request according to a coding scheme, such as coding scheme 900 described above with reference to FIG. 9 .

[0091] 15, method 1500 can proceed to (1510) to determine whether an ACK signal was successfully received in response to the individual ACK request frame sent at (1508). For example, with reference to FIG. 13, if antenna system 100 is operating in Mode 1 and the individual ACK request frame sent at (1508) includes code 914 (i.e., a mode-specific ACK request assigned to a Mode 1 request by coding scheme 900), a pulsed DC current signal (i.e., an ACK signal) is received by back-channel receiver 700 (shown in FIG. 7). On the other hand, with reference to FIG. 14, if antenna system 100 is operating in Mode 1 and the individual ACK request frame sent at (1508) includes code 918 (i.e., a mode-specific ACK request assigned to a Mode 3 request by coding scheme 900), a pulsed DC current signal (i.e., an ACK signal) is not received by back-channel receiver 700 (shown in FIG. 7).

[0092] 15 , if an ACK signal is received at 1510 in response to the individual ACK request frame sent at 1508, then method 1500 may proceed at 1512. At 1512, method 1500 may successfully read the current operating mode of antenna system 100. For example, as described above, if the individual ACK request frame sent at 1508 includes, for example, code 914, then successful receipt of the ACK signal at 1510 may provide a real-time indication at 1512 that the current operating mode of antenna system 100 is Mode 1.

[0093] 15 , if at 1510 an ACK signal was not received in response to the individual ACK request frame sent at 1508, method 1500 may proceed at 1514. At 1514, method 1500 may include sending a general ACK request frame similar to that described above with reference to 1502 for error detection. For example, as described above, if the individual ACK request frame sent at 1508 includes, for example, code 918, and antenna system 100 is operating, for example, in mode 1, then a pulsed DC current signal (i.e., ACK signal) will not be received. In that case, an error detection process must be performed to determine whether the failure to receive the pulsed DC current signal (i.e., ACK signal) at 1510 is due to antenna system 100 operating in a mode distinct from the mode associated with the individual ACK request frame sent at 1508, or whether the failure to receive the pulsed DC current signal (i.e., ACK signal) at 1510 is due to a modal antenna control channel error. More specifically, the method 1500 includes performing an error detection process by sending a general ACK request frame at 1514 .

[0094] 15 , at (1516), method 1500 may determine whether an ACK signal was successfully received in response to the general ACK request frame sent at (1514) in a manner similar to that described above with reference to (1504). As described above, method 1500 may perform an error detection process to determine whether antenna system 100 is operating in a mode distinct from the mode specified in the individual ACK request sent at (1508) or whether a modal antenna control channel error exists.

[0095] 15, if an ACK signal is not received in response to the general ACK request frame sent at 1514 at 1516, then method 1500 may proceed to 1506 to determine that a modal antenna control channel error exists. As discussed above with reference to 1506, method 1500 may perform a re-initialization process in response to determining that a modal antenna control channel error exists. In response to performing the initialization process at 1506, method 1500 may then return to 1502.

[0096] Referring to FIG. 15 , if an ACK signal is received in response to the general ACK request frame sent at 1514 at 1516, then method 1500 may proceed to 1518 to increment the antenna configuration mode counter. In response to incrementing the antenna configuration mode counter, method 1500 may then return to 1502. For example, if the individual ACK request frame sent at 1508 includes a unique code associated with mode 0, then the antenna configuration mode counter will be incremented by an increment of 1 and return to 1502. Thus, the next individual ACK request frame will include a unique code associated with mode 1. In that case, when method 1500 returns to 1518, the antenna configuration mode counter will be incremented by another increment of 1 and return to 1502, so that the next individual ACK request frame will include a unique code associated with mode 2. This process may be repeated until the antenna configuration mode counter has exhausted each of the multiple modes of antenna system 100.

[0097] While the subject matter of the present invention has been described in detail with reference to specific exemplary embodiments thereof, it will be recognized that those skilled in the art, upon achieving the above understanding, will be able to readily create modifications, variations, and equivalents of such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than limitation, and the present disclosure does not exclude the inclusion of such modifications, variations, and / or additions to the subject matter of the present invention that would be readily apparent to those skilled in the art. [Explanation of symbols]

[0098] 10 Modal Antenna 12 Circuit Board 14 Excitation antenna element 15 First parasitic element 16 First active tuning element 18 Second parasitic element 19 width 20 second active tuning element 21 Spacing 22 First Mode 24 Second Mode 26 Third Mode 100 Antenna System 102 Modal Antenna 104 Drive element 106 Parasitic elements 108 Tuned Circuit 110 Tunable Components 112 Radio Frequency Circuits 114 Transmission Line 116 Front-end module 118 Control circuit 120 First bias tee circuit 122 capacitor 124 Inductor 126 Second bias tee circuit 128 capacitors 129 First Circuit Board 130 Inductor 131 Second Circuit Board 132 processors 133 Control Devices 134 Carrier Signal Source 135 Control Devices 136 Modulator 138 Multiplexer 140 Amplifier 142 Bias Tee Circuit 400 Hourly Consistency Chart 401 Binary Signal 402 First Voltage Level 404 Second Voltage Level 406 sine wave signal 408 First Amplitude 410 Second Amplitude 420 Time-aligned Chart 430 sine wave signal 440 Multi-Valued Signals 452, 454, 456, 458 voltage levels 462, 464, 466, 468 amplitude 470 Training part 472 Data section 500 Tuned Circuit 502 Demodulator 504 Bias 506 Bias Tee Circuit 507 Multiplexer 508 Low-pass filter 510 Diode 512 Logic Circuit 514 Switch 516 Output 600 Back Channel Modulator 602 Switching Device 604 Current source 606 1st position 608 Second position 700 Backchannel Receiver 702 Operational Amplifier 704 Non-inverting input 706 Inverting Input 708 Output 710 Current Sensing Resistor 712 Load 900 coding system 902, 904, 906, 908, 910, 912, 914, 916, 918 codes 920 Multiple Bits

Claims

1. a modal antenna operable in multiple modes, each of the multiple modes being associated with a different radiation pattern; a tuning circuit configured to control the modal antenna to operate in each of the plurality of modes; a transmission line coupled to the tuning circuit; one or more control devices, modulating a control signal onto an RF signal to generate a modulated signal for communication over said transmission line to said tuned circuit; one or more control devices configured to generate an acknowledgement signal based at least in part on the control signal; An antenna system comprising:

2. 10. The antenna system of claim 1, wherein the one or more control devices are further configured to communicate the acknowledgement signal over the transmission path.

3. 2. The antenna system of claim 1, wherein the transmission line is a single coaxial cable.

4. the control signal comprises a data frame having a plurality of bits; the one or more control devices are configured to encode the plurality of bits associated with selected ones of the plurality of modes according to a coding scheme, the coding scheme identifying unique codes for a general acknowledgement request and a plurality of individual acknowledgement requests; 10. The antenna system of claim 1.

5. 5. The antenna system of claim 4, wherein the coding scheme is configured to identify a unique code for each of the plurality of modes.

6. 6. The antenna system of claim 5, wherein each of the plurality of individual acknowledgment requests is associated with a mode of the plurality of modes.

7. the one or more control devices: a backchannel modulator configured to generate the acknowledgement signal based at least in part on the control signal and to communicate the acknowledgement signal over the transmission path; a back-channel receiver configured to detect the acknowledgement signal, the back-channel receiver coupled to the back-channel modulator via the transmission path; The antenna system of claim 1 further comprising:

8. the back channel modulator is a switchable current source; the back-channel receiver is a current sensor; 8. The antenna system of claim 7.

9. a first circuit board comprising the back channel modulator; a second circuit board comprising the back-channel receiver, the second circuit board being physically separate from the first circuit board; At least one of the tuning circuit or the modal antenna is provided on the first circuit board; 8. The antenna system of claim 7.

10. the modal antenna comprises an excited element and a parasitic element positioned proximate to the excited element; the tuning circuit is further configured to control one or more electrical characteristics associated with the parasitic element based at least in part on the control signal.

10. The antenna system of claim 1.

11. modulating, by an RF circuit, a control signal onto an RF signal to generate a modulated signal; communicating the modulated signal to a tuning circuit via a transmission line; demodulating the control signal from the modulated signal by the tuning circuit; processing the control signal by the tuning circuit to obtain a code; determining, by said tuning circuit, whether said code comprises an acknowledgement request; communicating an acknowledgement signal to the RF circuitry over the transmission line in response to determining that the code comprises an acknowledgement request; 10. A method for controlling a modal antenna, comprising:

12. determining whether the code comprises an acknowledgement request, determining, by said tuning circuit, whether said code is associated with a selected one of a plurality of modes of said modal antenna; determining, by the tuning circuit, whether the code is an acknowledgement code associated with a mode of the plurality of modes of the modal antenna in response to determining that the code is not associated with a selected mode of the plurality of modes of the modal antenna; The method of claim 11 further comprising:

13. determining, by the tuning circuit, in response to determining that the code is an acknowledgement code associated with a mode of the plurality of modes of the modal antenna, whether the mode associated with the acknowledgement code matches a current mode of the modal antenna.

13. The method of claim 12, further comprising:

14. communicating an acknowledgement signal to the RF circuitry over the transmission path in response to determining that the mode associated with the acknowledgement code matches the current mode of the modal antenna.

14. The method of claim 13, further comprising:

15. maintaining the current mode of the modal antenna if the mode associated with the acknowledgement code does not match the current mode of the modal antenna.

14. The method of claim 13, further comprising:

16. and in response to determining that the code is associated with a selected one of the plurality of modes of the modal antenna, controlling, by the tuning circuit, an electrical characteristic associated with a parasitic element of the modal antenna based at least in part on the control signal to cause the modal antenna to operate in the selected one of the plurality of modes.

13. The method of claim 12, further comprising:

17. communicating an acknowledgement signal to the RF circuitry over the transmission line; communicating the acknowledgement signal to the RF circuitry over the transmission line; detecting, by the RF circuitry, the acknowledgement signal; The method of claim 11 further comprising:

18. The method of claim 11 , wherein the acknowledgement signal is a single-bit DC current incremental pulse.

19. a modal antenna operable in multiple modes, each of the multiple modes being associated with a different radiation pattern; a radio frequency (RF) circuit comprising a front-end module and a first control device; A transmission path; an antenna circuit coupled to the RF circuit via the transmission line, the antenna circuit comprising a tuning circuit and a second control device, the second control device configured to generate an acknowledgement signal and to communicate the acknowledgement signal over the transmission line, the acknowledgement signal acknowledging operation of the modal antenna in a selected mode; Equipped with the first control device is configured to detect the acknowledgement signal; Antenna system.

20. the first control device is a current sensor; the second control device is a switchable current source; 20. The antenna system of claim 19.

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