Multiband radio frequency communication device with a shared radiating structure

Abstract

In a particular embodiment, a multiband radio frequency communication device is disclosed that includes a first RF communication section configured for communication in a first RF band and including a first RF circuit. The device also includes a second RF communication section configured for communication in a second RF band different from the first RF band and including a second RF circuit, a second ground plane, and a radiating structure including an antenna. In addition, the device also includes a coupling network including an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that the second RF communication section provides a radiating structure for transmission of signals generated by the first RF circuit. The device also includes an isolation arrangement configured to electrically decouple the first RF communication section from the second RF communication section for high-frequency operation.

Description

MULTIBAND RADIO FREQUENCY COMMUNICATION DEVICE WITH A SHARED RADIATING STRUCTUREFIELD OF THE TECHNOLOGY

[0001] The subject disclosure relates to apparatuses, systems, and methods for radio frequency (RF) communication and, more particularly, to multiband RF communication devices in which a first RF communication section is configured to use at least part of a second RF communication section as a radiating structure.BACKGROUND

[0002] Radio frequency (RF) communication devices are increasingly expected to support communication in multiple RF bands. In many implementations, a device may communicate in a first RF band using a first communication protocol and communicate in a second RF band using a second communication protocol. Providing such multiband capability in a compact device may present significant design challenges.

[0003] One conventional approach to supporting communication in multiple RF bands is to provide separate RF communication sections for the respective RF bands, each with a corresponding RF circuit and antenna. Although this approach may permit operation in multiple RF bands, use of separate antennas may increase device size, weight, cost, and design complexity. In addition, when multiple antennas are positioned in close proximity, electromagnetic interaction between the antennas may reduce RF performance.

[0004] Another conventional approach is to combine RF signals associated with different RF bands and provide the combined signals to a shared antenna using a diplexer or other RF combining structure. Although this approach may reduce the number of antennas, implementation of an efficient combining structure may be difficult, particularly when the RF bands are separated significantly in frequency. Such combining structures may also increase cost and electrical complexity.

[0005] These issues may be particularly significant in compact sensor devices in which available space, weight, and packaging flexibility are limited. For example, in a tire pressure monitoring system (TPMS) sensor, it may be desirable to support communication in multiple RF bands while maintaining a compact form factor suitable for mounting w ithin a tire or on a valve assembly. It may further be desirable to introduce support for an additional RF band or communication protocol without redesigning the device to accommodate an additional dedicated antenna or a complex RF combiner.

[0006] Accordingly, there is a need for improved techniques for implementing multiband RF communication in compact devices.SUMMARY

[0007] The following summary is meant to help one skilled in the art understand the various presently disclosed combinations of features. It is not meant to unduly limit the scope of any- pending or future claims relating to the disclosure.

[0008] According to embodiments of the present disclosure, apparatuses, systems, and methods are provided for enabling a device that communicates in multiple radio frequency (RF) bands to use an existing RF communication section as a radiating structure for another RF communication section. An output of a first RF communication section may be coupled, through an impedance matching arrangement, to a ground plane or other conductive structure of a second RF communication section so that an existing antenna structure and associated metallic structure of the second RF communication section radiate signals for the first RF communication section. This approach can allow a compact device to add communication capability in another RF band without requiring a separate dedicated antenna or a complex RF combiner, thereby reducing space requirements, cost, and design complexity. In a particularly useful example, a tire pressure monitoring system (TPMS) sensor may use an existing ultrahigh frequency (UHF) RF section, including its ground plane and antenna structure, to also support Bluetooth Low Energy (BLE) communication.

[0009] In a particular embodiment, a tire pressure monitoring system (TPMS) sensor is disclosed that includes a first radio frequency (RF) communication section configured to communicate in a first RF band and including a first RF circuit. The sensor also includes a second RF communication section configured to communicate in a second RF band different from the first RF band and includes a second RF circuit, a second ground plane, and an antenna operatively associated with the second ground plane. In addition, the sensor also includes an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that signals generated by the first RF circuit are transmitted using at least part of the second RF communication section including the antenna. The sensor also includes one or more isolation components configured to decouple the first RF communication section from the second RF communication section such that the second RF communication section remains operable for communication in the second RF band.

[0010] In a particular embodiment, a multiband radio frequency communication device is disclosed that includes a first RF communication section configured for communication in a first RF band and including a first RF circuit. The device also includes a second RFcommunication section configured for communication in a second RF band different from the first RF band and including a second RF circuit, a second ground plane, and an antenna. In addition, the device also includes a coupling network including an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that the second RF communication section provides a radiating structure for transmission of signals generated by the first RF circuit. The device also includes an isolation arrangement configured to electrically decouple the first RF communication section from the second RF communication section for high-frequency operation.

[0011] In another embodiment, a method of operating a multiband radio frequency communication device is disclosed that includes generating first-band RF signals in a first RF band with a first RF communication section. The method also includes coupling the output of a first RF circuit of the first RF communication section to a ground plane of a second RF communication section through an impedance matching circuit. In this embodiment, the second RF communication section is configured for communication in a second RF band different from the first RF band. In addition, the method also includes transmitting the firsthand RF signals using a radiating structure of the second RF communication section that includes an antenna associated with the second RF communication section.

[0012] The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular descriptions of exemplary embodiments of the invention as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts of exemplary embodiments of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] One or more aspects of the present disclosure are discussed below with reference to the accompanying Figures. It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components may be included in one functional block or element.

[0014] Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. For purposes of clarity, however, not every' component may be labeled in every drawing. The Figures are provided for the purposes of illustration and explanation and are not intended to be limiting. In the Figures:

[0015] FIG. 1 is a block diagram of an example multiband communication device configured to use one RF communication section as a radiating structure for another RF communication section in accordance with at least one embodiment of the present disclosure.

[0016] FIG. 2 is a block diagram of an example tire sensor configured to use one RF communication section as a radiating structure for another RF communication section in accordance with at least one embodiment of the present disclosure.

[0017] FIG. 3 is a flowchart of an example method of using one RF communication section as a radiating structure for another RF communication section in accordance with at least one embodiment of the present disclosure.

[0018] FIG. 4 is a flowchart of an example method of operating a multiband radio frequency (RF) communication device in accordance with at least one embodiment of the present disclosure.

[0019] FIG. 5 is a flowchart of another example method of operating a multiband radio frequency (RF) communication device in accordance with at least one embodiment of the present disclosure.

[0020] FIG. 6 is a flowchart of another example method of operating a multiband radio frequency (RF) communication device in accordance with at least one embodiment of the present disclosure.DETAILED DESCRIPTION

[0021] The terminology used herein for the purpose of describing particular examples is not intended to be limiting for further examples. Whenever a singular form such as “a”, “an” and “the” is used and using only a single element is neither explicitly nor implicitly defined as being mandatory, further examples may also use plural elements to implement the same functionality. Likewise, when a functionality is subsequently described as being implemented using multiple elements, further examples may implement the same functionality using a single element or processing entity. It will be further understood that the terms “comprises”, “comprising”, “includes” and / or “including”, when used, specify the presence of the stated features, integers, steps, operations, processes, acts, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, processes, acts, elements, components and / or any group thereof.

[0022] It will be understood that when an element is referred to as being “connected” or “coupled” to another element, the elements may be directly connected or coupled via one or more intervening elements. If two elements A and B are combined using an “or”, this is to be understood to disclose all possible combinations, i.e. only A, only B, as well as A and B. Analternative wording for the same combinations is “at least one of A and B”. The same applies for combinations of more than two elements.

[0023] Accordingly, while further examples are capable of various modifications and alternative forms, some particular examples thereof are shown in the figures and will subsequently be described in detail. However, this detailed description does not limit further examples to the particular forms described. Further examples may cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. Like numbers refer to like or similar elements throughout the description of the figures, which may be implemented identically or in modified form when compared to one another while providing for the same or a similar functionality.

[0024] When small devices need to support transmission at two different frequency bands, integrating two separate RF sections including the necessary antennas while maintaining an optimized form factor presents a challenge. An RF section may refer to an RF circuit, such as an amplifier, encoder, oscillator, and / or other RF circuitry, together with an associated antenna and ground plane. Two common approaches to achieving such functionality include using separate RF circuits with two distinct antennas or employing a diplexer to combine two RF signals and direct them to a single antenna while providing impedance matching and acceptable efficiency. Using two separate antennas can lead to electromagnetic interactions that degrade RF performance. Additionally, this approach requires more space because the antenna structure is effectively duplicated. Combining both RF signals into a single antenna can help optimize space and reduce cost. However, designing an efficient diplexer may be particularly challenging when the two frequency bands are significantly different.

[0025] In a multiband device that includes two radio frequency communication sections, a first RF communication section may use a second RF communication section as a radiating structure, thereby reducing or eliminating the need for a separate dedicated antenna for the first RF communication section. In some examples, an RF output of the first RF communication section is connected to a ground plane of the second RF communication section through an impedance matching arrangement. The impedance matching arrangement may tune conductive structure associated with the second RF communication section such that the second RF communication section presents a desired impedance to the output of the first RF communication section at the first RF band. One or more decoupling or isolation arrangements may be provided between the RF communication sections so that the second RF communication section may provide the radiating structure for the first RF communication section while remaining operable in its native RF band. This approach maysave space and money and may reduce device complexity. As such, embodiments are particularly useful in devices where a small form factor is important, including tire pressure monitoring system (TPMS) sensors and other tire-mounted sensors in which weight and occupied volume may desirably be minimized.

[0026] In some examples, the portion of the second RF communication section that is used for transmission of signals generated by the first RF communication section may be referred to as a radiating structure. The radiating structure may include, in various combinations, the ground plane of the second RF communication section, an antenna element of the second RF communication section, one or more conductive traces, one or more conductive pads, one or more conductive interconnect structures, one or more shielding structures, one or more package structures of the second RF circuit, one or more lead frame portions, and / or other metallic structures associated with the second RF communication section. Thus, in some implementations, transmission by the first RF communication section is carried out using not only an antenna element of the second RF communication section, but also one or more additional conductive portions of the second RF communication section that collectively behave as an effective radiator at the first RF band.

[0027] In some examples, the coupling between the first RF communication section and the second RF communication section is configured such that the second RF communication section remains operable for communication in its native RF band while also providing the radiating structure for the first RF communication section. For example, the impedance matching and decoupling arrangement may be selected such that communication performance of the second RF communication section in the second RF band is preserved or only minimally affected. Such communication performance may include one or more of impedance matching, return loss, radiated efficiency, gain, sensitivity, range, protocol compliance, and / or signal quality in the second RF band.

[0028] In a particular implementation directed to a multiband device configured for ultrahigh frequency (UHF) communication and Bluetooth communication, such as Bluetooth Low Energy (BLE), the full UHF RF section, including its RF circuit, ground plane, and existing UHF antenna, may be used as a radiating structure for the BLE section with a particular impedance coupling. For example, a network matching circuit may connect the BLE output to the UHF RF section in order to provide impedance matching for improved BLE radiated power. One or more decoupling components may isolate the UHF RF section from the BLE RF section so that the UHF RF section may continue to operate in its native RF band while also serving as a radiating structure for BLE communication. The use of the full UHF RFsection as, for example, a 2.4 GHz radiating structure permits implementation of BLE technology without adding an extra dedicated antenna or a complex electronic combiner structure. Conventional techniques would require two separate antennas or a complex RF combiner connected to one antenna and thus would involve greater complexity and occupied space.

[0029] The decoupling, shielding, and / or isolation between the RF communication sections may be implemented in various ways. In some examples, one or more inductive components are provided in one or more supply paths. In some examples, one or more capacitive components, chokes, filters, resonant structures, transmission-line structures, grounded shielding structures, printed circuit board layout separation structures, conductive partitions, and / or combinations thereof may be used. Accordingly, the present disclosure is not limited to any particular isolation mechanism, provided that sufficient isolation is achieved to permit the second RF communication section to provide the radiating structure for the first RF communication section while maintaining desired operation of the second RF communication section in the second RF band.

[0030] Although particular examples herein refer to Bluetooth communication and ultrahigh frequency (UHF) communication, the disclosed techniques are not limited to those particular RF bands or protocols. More generally, embodiments may be implemented using any two or more RF communication sections operating in respective RF bands, whether adjacent, overlapping, or separated from one another. In some examples, a higher-frequency RF communication section may use a lower-frequency RF communication section as a radiating structure. In some examples, a lower-frequency RF communication section may use a higher-frequency RF communication section as a radiating structure. In some examples, one RF communication section may provide a radiating structure for another in a device configured for communication in more than two RF bands.

[0031] For further explanation, FIG. 1 sets forth a block diagram of an example multiband RF device 100 in accordance with at least one embodiment of the present disclosure. The multiband RF device includes a high frequency band component 102 and a low frequency band component 104. As used herein, "high frequency band” and "low frequency band” are relative terms intended to convey that the high frequency band (e g., 2-5 GHz) is higher than the low frequency band (e.g., 300-3000 MHz) and should not be constmed as limited to particular frequency bands. High frequency band component 102 includes a high frequency RF section including a high frequency RF circuit 122 and a first ground plane 124. Low frequency band component 104 includes a low frequency RF section including a lowfrequency RF circuit 142, a second ground plane 144, and an antenna 146. The output of the high frequency RF circuit 122 is provided to a first impedance matching circuit 126. The output of the first impedance matching circuit 126 is provided to the second ground plane 144 of the low frequency band component 104. The output of the low frequency RF circuit 142 is provided to a second impedance matching circuit 148. The output of the second impedance matching circuit 148 is provided to a first end of antenna 146. High frequency band component 102 and low frequency band component 104 are coupled to the same power source 106 via a positive power connection 110 and a negative power connection 112. In some examples, power source 106 is a battery. Respective decoupling components 114, 116 in positive power connection 110 and negative power connection 112 decouple the power connections of low frequency band component 104 from high frequency band component 102. In some examples, decoupling components 114, 116 are inductors. A second end of antenna 146 is coupled to the second ground plane 144 via a capacitor 150.

[0032] In some examples, the first impedance matching circuit 126 and / or the second impedance matching circuit 148 may include one or more inductors, one or more capacitors, one or more resistors, one or more transmission-line elements, one or more tunable elements, and / or one or more parasitic elements selected to provide a desired impedance transformation. In general, impedance matching refers to selecting and arranging circuit elements so that a source sees an electrical load that permits efficient transfer of RF energy, rather than causing an undesired amount of the RF energy to be reflected back toward the source. Stated differently, an impedance matching circuit may be used to transform an impedance presented by a conductive structure, antenna structure, ground plane, and / or other radiating structure into an impedance that is suitable for efficient operation of an RF output stage at a selected frequency band. In the example of FIG. 1, first impedance matching circuit 126 may be configured such that the output of the first RF circuit 122 sees, at the first RF band, an impedance corresponding to a conjugate impedance of at least part of the radiating structure associated with the low frequency band component 104. In this way, RF energy- generated by the first RF circuit 122 may be coupled efficiently into the second ground plane 144 and associated conductive structure of the low frequency band component 104, such that antenna 146, second ground plane 144, and / or one or more other conductive portions of low frequency band component 104 participate in radiation of signals in the first RF band. Thus, the low frequency band component 104 may provide an effective radiating structure for the high frequency band component 102 even though the low frequency band component 104 is also configured for communication in a different RF band. Likewise, second impedancematching circuit 148 may be configured to provide desired impedance matching between the low frequency RF circuit 142 and antenna 146 for communication in the second RF band. Accordingly, the respective impedance matching circuits may permit the different RF communication sections to operate in different RF bands while allowing one RF communication section to make use of conductive structure associated with another RF communication section for radiation of RF signals.

[0033] In some examples, significant decoupling may be provided between the first RF communication section and the second RF communication section such that the sections are sufficiently isolated from one another at RF frequencies of interest. Such decoupling may reduce undesired loading, back-coupling, detuning, current flow, and / or signal leakage between the sections. For example, one or more decoupling components 114. 116, one or more filtering components, one or more shielding structures, and / or one or more layout-based isolation features may be used so that the first RF communication section may inject RF energy into the radiating structure of the second RF communication section for transmission in the first RF band while the second RF communication section remains capable of communication in the second RF band. Accordingly, the decoupling arrangement may help preserve desired RF performance of the second RF communication section while enabling multiband operation without a separate dedicated antenna for the first RF communication section.

[0034] Using this configuration, high frequency band component 102 uses antenna 146 of low frequency band component 104 for high frequency signal transmission. Because the RF output of the high frequency RF circuit 122 is connected to the second ground plane 144 of the low frequency band component 104 through impedance matching circuit 126, the impedance matching circuit 126 may tune the conductive structure of the low frequency band component 104 such that the low frequency band component 104 provides a desired radiating structure for signals generated by the high frequency RF circuit 122. Thus, the low frequency RF section is used as a radiating structure for the high frequency RF section. Because high frequency band component 102 no longer needs a separate dedicated antenna, the form factor of multiband RF device 100 may be reduced. Further, because no diplexer is needed, the complexity of multiband RF device 100 may also be reduced.

[0035] In some examples, the radiating structure used for transmission of signals generated by the high frequency band component 102 includes not only antenna 146, but also second ground plane 144 and one or more additional conductive structures of low frequency band component 104. Accordingly, references herein to using the antenna 146 of low frequencyband component 104 for transmission may also encompass use of a larger conductive structure associated with low frequency band component 104, including one or more metallic structures that participate in radiation at the high frequency band.

[0036] In this manner, the arrangement of FIG. 1 permits a first RF communication section to use conductive structure associated with a second RF communication section as a radiating structure for transmission in a different RF band. As a result, multiband communication may be implemented without requiring a separate dedicated antenna for the first RF communication section or a diplexer-type combiner structure, which may reduce device size, cost, and electrical complexity. This may be particularly beneficial in compact devices in which available space and weight are constrained. Accordingly, the configuration of FIG. 1 may facilitate addition of communication capability in another RF band while preserving a compact device architecture.

[0037] As mentioned above, techniques in accordance with the present disclosure have particular applicability to tire sensors such as TPMS sensors or tire-mounted sensors. For further explanation, FIG. 2 sets forth a block diagram of an example tire sensor 200 in accordance with at least one embodiment of the present disclosure. For example, tire sensor 200 may be a tire-mounted sensor or a TPMS sensor. In various examples, tire sensor 200 is mounted on an inner liner of a tire or on the valve of a tire. Tire sensor 200 includes a Bluetooth Low Energy (BLE) transmitter 202 and an ultrahigh frequency (UHF) section 203 including an integrated sensing device 204, an antenna 246. and a UHF ground plane 244 coupled to integrated sensing device 204 and antenna 246. BLE transmitter 202 and integrated sensing device 204 are coupled to a battery 206 via a positive power connection 210 and a negative power connection 212. Respective decoupling components 214, 216 in positive power connection 210 and negative power connection 212 decouple the power supply to integrated sensing device 204 from transmitter 202. In some examples, decoupling components 214, 216 are inductors. BLE transmitter is configured for bidirectional communication with, for example, a vehicle-side vehicle control system 290.

[0038] Integrated sensing device 204 includes a microcontroller 262, one or more accelerometers 264, and pressure sensor 266 for sensing tire pressure. For example, one or more accelerometers 264 may sense acceleration in the radial plane (z-plane), lateral plane (y -plane), and / or tangential plane (x-plane), and output an electric pulse signal responsive to sensed acceleration, including but not limited to signals indicative of ground strikes. Pressure sensor 266 may be a microelectromechanical systems (MEMS) sensor or other device that is similarly configured to sense air pressure within the tire. Integrated sensing device 204 alsoincludes UHF RF circuit 242. UHF RF circuit 242 is configured to generate electrical signals for UHF RF transmission. These RF transmissions may include measurements from sensors such as the accelerometer and pressure sensor. In some examples, microcontroller 262, sensors including one or more accelerometers 264 and pressure sensor 266, and UHF RF circuit 242 are implemented by an ASIC. Integrated sensing device 204 is coupled to UHF ground plane 244. Integrated sensing device 204 also includes UHF impedance matching circuit 248 that receives the output of UHF RF circuit 242 and provides a matched output to a first end of antenna 246 of integrated sensing device 204. A second end of antenna 246 is coupled to UHF ground plane 244 via capacitor 254.

[0039] BLE transmitter 202 includes a microcontroller 252. which may include or implement a processor, an Application Specific Integrated Circuit (ASIC), a digital signal processor (DSP), a programmable logic array (PLA) such as a field programmable gate array (FPGA), or other data computation unit in accordance with the present disclosure. BLE transmitter 202 also includes BLE RF circuit 222. BLE RF circuit 222 generates electrical signals for 2.4 GHz band RF transmission. These RF transmissions may include measurements from sensors such as the accelerometer and pressure sensor. BLE transmitter 202 also includes BLE ground plane 224 coupled to the BLE RF circuit 222. Thus, the BLE RF section includes at least the BLE RF circuit 222 and BLE ground plane 224.

[0040] The output of BLE RF circuit 222 is provided to BLE impedance matching circuit 226. The output of BLE impedance matching circuit 226 is provided to UHF ground plane 244 of integrated sensing device 204. Thus, in this implementation, the full UHF RF section, including UHF RF circuit 242, UHF ground plane 244, and existing UHF antenna 246, provides a radiating structure for the BLE section of BLE transmitter 202 through the impedance coupling provided by BLE impedance matching circuit 226. This impedance matching circuit may be used to connect the BLE output to the UHF RF section in order to provide proper impedance matching for improved BLE radiated power. Because the RF output of the BLE RF section is connected to the UHF ground plane 244 of the UHF RF section through the tuned impedance matching circuit 226, the conductive structure of the UHF RF section may provide a desired radiating structure for signals generated by BLE RF circuit 222. The UHF RF section may remain operable in its native RF band.

[0041] The use of the full UHF RF section 203 acting as, for example, a 2.4 GHz antenna permits the implementation of BLE technology without adding any extra dedicated antenna or complex electronic structure. The decoupling components separate the two sections between each other so that one may become the antenna of the other. Conventionaltechniques would have required two separate antennas or a complex RF combiner connected to one antenna, which requires more complexity and space in the form factor.

[0042] In some examples, the disclosed arrangement permits introduction of an additional RF communication capability while preserving an existing mechanical assembly, existing packaging envelope, existing printed circuit board outline, existing antenna structure, existing housing geometry, and / or an existing manufacturing process associated with the device. For example, in a TPMS sensor, an additional communication band may be implemented while maintaining a valve-mounted form factor, tire-mounted form factor, battery location, sensor package configuration, and / or assembly process already used for a previously deployed design. Such reuse of an existing mechanical and manufacturing architecture may reduce redesign effort, tooling changes, qualification effort, and manufacturing cost.

[0043] Although FIG. 2 illustrates a TPMS sensor implementation including a BLE transmitter 202 and a UHF section 203, the disclosed architecture may likewise be used in other compact multiband RF devices in which available space, device volume, device weight, cost, and / or electrical complexity are constrained. In such devices, one existing RF communication section may be repurposed to provide at least part of a radiating structure for another RF communication section, thereby reducing or eliminating a need for a further dedicated antenna or a diplexer-ty pe combiner structure.

[0044] In this manner, the configuration of FIG. 2 permits a TPMS sensor to support communication in multiple RF bands by allowing one RF communication section to use conductive structure associated with another RF communication section as a radiating structure. As a result, an additional communication capability7, such as BLE communication, may be implemented without requiring a separate dedicated antenna or a complex RF combiner structure, thereby reducing space requirements, cost, and electrical complexity. This may be particularly beneficial in TPMS sensors and other tire-mounted devices in which size, weight, and packaging constraints are significant. Accordingly, the configuration of FIG. 2 may facilitate introduction of additional RF communication capability while preserving a compact sensor architecture.

[0045] For further explanation, FIG. 3 sets forth a method of using an existing RF section as an antenna for another RF section in accordance with at least one embodiment of the present disclosure. The method of FIG. 3 includes coupling 302 the output of a first radio frequency communication device to a ground plane of a second radio frequency communication device via an impedance matching circuit. In some examples, coupling 302 the output of a first radio frequency communication device to a ground plane of a second radio frequencycommunication device via an impedance matching circuit is carried out as shown in FIGS. 1 or 2. For example, coupling 302 the output of a first radio frequency communication device to a ground plane of a second radio frequency communication device via an impedance matching circuit can be carried out by coupling the output of high frequency band RF circuit 122 in the high frequency band component 102 to the ground plane 144 of the low frequency band component 104.

[0046] The method also includes transmitting 304 signals generated by the first radio frequency communication device using an antenna of the second radio frequency communication device. In some examples, as show n in FIG. 1, signals generated by high frequency RF circuit 122 are transmitted using antenna 146 of low frequency band component 104.

[0047] In some examples, transmitting 304 signals generated by the first radio frequency communication device includes transmitting the signals using a radiating structure of the second radio frequency communication device that includes the antenna and a ground plane of the second radio frequency communication device. In some examples, the radiating structure further includes one or more other conductive portions of the second radio frequency communication device. In some examples, the method further includes operating the second radio frequency communication device in its native RF band while the second radio frequency communication device remains available to provide the radiating structure for transmission of signals generated by the first radio frequency communication device.

[0048] For further explanation, FIG. 4 sets forth a method of operating a multiband radio frequency communication device according to at least one embodiment of the present disclosure. In some examples, the method of FIG. 4 may be carried out in a device that includes a first RF communication section configured for communication in a first RF band and a second RF communication section configured for communication in a second RF band different from the first RF band. In some examples, the first RF communication section may be configured to use a radiating structure of the second RF communication section, including an antenna associated with the second RF communication section, for transmission of signals in the first RF band. In some examples, the method of FIG. 4 may be carried out in a compact multiband device, such as a tire pressure monitoring system (TPMS) sensor, in order to provide communication in multiple RF bands without requiring a separate dedicated antenna for each RF band.

[0049] The method of FIG. 4 includes generating 402 first-band RF signals in a first RF band with a first RF communication section. Generating 402 first-band RF signals in a first RFband with a first RF communication section may be carried out by energizing a first RF circuit of the first RF communication section to produce RF transmit signals at the first RF band. In some examples, this may include operating a Bluetooth Low Energy (BLE) RF circuit to generate RF signals in the 2.4 GHz band for wireless transmission. In a TPMS implementation, the first RF communication section may generate the first-band RF signals responsive to sensor information, such as tire pressure data, acceleration data, identification data, and / or status data, for communication to an external device. The generated first-band RF signals may then be provided to an impedance matching circuit for coupling to the second RF communication section as described herein.

[0050] The method of FIG. 4 also includes coupling 404 an output of a first RF circuit of the first RF communication section to a ground plane of a second RF communication section through an impedance matching circuit. The second RF communication section is configured for communication in a second RF band different from the first RF band. Coupling 404 an output of a first RF circuit of the first RF communication section to a ground plane of a second RF communication section through an impedance matching circuit may be carried out by electrically connecting the output of the first RF circuit to an impedance matching circuit and connecting the impedance matching circuit to the ground plane of the second RF communication section. In some examples, the impedance matching circuit is selected to transform an impedance of a radiating structure associated with the second RF communication section to provide a desired match for the output of the first RF circuit in the first RF band. In this manner, RF signals generated by the first RF circuit may be injected into the second RF communication section, which is configured for communication in a second RF band different from the first RF band. In some examples, one or more isolation or decoupling components may be provided between the first RF communication section and the second RF communication section such that the second RF communication section remains operable in the second RF band.

[0051] In addition, the method of FIG. 4 includes transmitting 406 the first-band RF signals using a radiating structure of the second RF communication section that includes an antenna associated with the second RF communication section. Transmitting 406 the first-band RF signals using a radiating structure of the second RF communication section that includes an antenna associated with the second RF communication section may be carried out by applying the first-band RF signals, through the impedance matching circuit, to the radiating structure of the second RF communication section so that the radiating structure radiates the first-band RF signals. In some examples, the radiating structure includes not only the antenna,but also a ground plane and one or more other conductive portions of the second RF communication section that participate in radiation at the first RF band. In this manner, the second RF communication section provides an effective radiator for the first RF communication section without requiring a separate dedicated antenna for the first RF band. In some examples, the second RF communication section remains operable for communication in the second RF band while also providing the radiating structure for transmission of the first-band RF signals.

[0052] In this manner, the method of FIG. 4 permits a first RF communication section to use a radiating structure of a second RF communication section to transmit first-band RF signals without requiring a separate dedicated antenna for the first RF band. As a result, device size, cost, and electrical complexity may be reduced, which may be particularly beneficial in compact devices such as TPMS sensors in which available space and weight are constrained. The method also permits introduction of an additional RF communication capability while allowing the second RF communication section to remain operable in its native RF band. Accordingly, the method of FIG. 4 may facilitate implementation of multiband communication in a compact device while preserving an existing device architecture.

[0053] For further explanation, FIG. 5 sets forth another method of operating a multiband radio frequency communication device according to at least one embodiment of the present disclosure. The method of FIG. 5 is similar to the method of FIG. 4 in that the method of FIG. 5 includes all of the elements and steps of FIG. 4.

[0054] However, the method of FIG. 5 includes isolating 502 the first RF communication section from the second RF communication section using one or more isolation components. Isolating 502 the first RF communication section from the second RF communication section using one or more isolation components may be carried out by placing one or more isolation components between the first RF communication section and the second RF communication section in one or more electrical paths between the sections. In some examples, the one or more isolation components may include one or more inductors, capacitors, chokes, filters, grounded shielding structures, layout-based separation structures, and / or combinations thereof configured to reduce undesired coupling between the sections. In this manner, the first RF communication section may use a radiating structure of the second RF communication section while the second RF communication section remains operable in its native RF band. In some examples, the one or more isolation components are provided in one or more power supply connections of the first RF communication section and the second RF communication section.

[0055] For further explanation, FIG. 6 sets forth another method of operating a multiband radio frequency communication device according to at least one embodiment of the present disclosure. The method of FIG. 6 is similar to the method of FIG. 4 in that the method of FIG. 6 includes all of the elements and steps of FIG. 4.

[0056] However, the method of FIG. 6 includes communicating 602 in the second RF band using the second RF communication section while the second RF communication section remains operable in the second RF band. Communicating 602 in the second RF band using the second RF communication section while the second RF communication section remains operable in the second RF band may be carried out by operating a second RF circuit of the second RF communication section to generate RF transmit signals in the second RF band and providing those RF transmit signals to an antenna associated with the second RF communication section. In some examples, the second RF communication section communicates in the second RF band through a second impedance matching circuit while one or more isolation components reduce undesired interaction with the first RF communication section. In this manner, the second RF communication section continues to perform its native RF communication function in the second RF band notwithstanding that the second RF communication section also provides a radiating structure for first-band RF signals. In some examples, the second RF band is a UHF band and the second RF communication section transmits sensor information from a TPMS sensor in the UHF band.

[0057] Advantages and features of the present disclosure can be further described by the following statements:

[0058] 1. A tire pressure monitoring system (TPMS) sensor comprising: a first radio frequency (RF) communication section configured to communicate in a first RF band and including a first RF circuit; a second RF communication section configured to communicate in a second RF band different from the first RF band and including a second RF circuit, a second ground plane, and an antenna operatively associated with the second ground plane; an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that signals generated by the first RF circuit are transmitted using at least part of the second RF communication section including the antenna; and one or more isolation components configured to decouple the first RF communication section from the second RF communication section such that the second RF communication section remains operable for communication in the second RF band.

[0059] 2. The TPMS sensor of statement 1, wherein the first RF band is a 2.4 GHz band and the second RF band is an ultrahigh frequency (UHF) band.

[0060] 3. The TPMS sensor of statement 1 or 2, wherein the first RF communication section is a Bluetooth Low Energy (BLE) communication section.

[0061] 4. The TPMS sensor of any of statements 1-3, wherein the second RF communication section further includes a second impedance matching circuit coupling an output of the second RF circuit to a first end of the antenna.

[0062] 5. The TPMS sensor of any of statements 1-4, wherein a second end of the antenna is coupled to the second ground plane through a capacitor.

[0063] 6. The TPMS sensor of any of statements 1-5, wherein the one or more isolation components include one or more inductors in one or more power supply connections.

[0064] 7. The TPMS sensor of any of statements 1-6, wherein the signals generated by the first RF circuit are transmitted using a radiating structure that includes the second ground plane and the antenna.

[0065] 8. The TPMS sensor of any of statements 1-7, wherein the radiating structure further includes one or more metallic structures of the second RF communication section.

[0066] 9. A multiband radio frequency communication device comprising: a first RF communication section configured for communication in a first RF band and including a first RF circuit; a second RF communication section configured for communication in a second RF band different from the first RF band and including a second RF circuit, a second ground plane, and an antenna; a coupling network including an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that the second RF communication section provides a radiating structure for transmission of signals generated by the first RF circuit; and an isolation arrangement configured to electrically decouple the first RF communication section from the second RF communication section at least for high-frequency operation.

[0067] 10. The multiband radio frequency communication device of statement 9, wherein the first RF band is higher than the second RF band.

[0068] 11. The multiband radio frequency communication device of statement 9 or 10, wherein the first RF band is a 2.4 GHz band.

[0069] 12. The multiband radio frequency communication device of any of statements 9-11, wherein the second RF band is a sub-GHz band.

[0070] 13. The multiband radio frequency communication device of any of statements 9-12, wherein the radiating structure includes the second ground plane, the antenna, and one or more conductive structures of the second RF communication section.

[0071] 14. The multiband radio frequency communication device of any of statements 9-13, wherein the second RF communication section remains configured to communicate in the second RF band while the first RF communication section uses the radiating structure for communication in the first RF band.

[0072] 15. The multiband radio frequency communication device of any of statements 9-14, wherein the multiband radio frequency’ communication device is implemented in a tiremounted sensor.

[0073] 16. A method of operating a multiband radio frequency communication device, the method comprising: generating first-band RF signals in a first RF band with a first RF communication section; coupling an output of a first RF circuit of the first RF communication section to a ground plane of a second RF communication section through an impedance matching circuit, the second RF communication section being configured for communication in a second RF band different from the first RF band; and transmitting the first-band RF signals using a radiating structure of the second RF communication section that includes an antenna associated with the second RF communication section.

[0074] 17. The method of statement 16, further comprising isolating the first RF communication section from the second RF communication section using one or more isolation components.

[0075] 18. The method of statement 16 or 17, further comprising communicating in the second RF band using the second RF communication section while the second RF communication section remains operable in the second RF band.

[0076] 19. The method of any of statements 16-18, wherein the first RF communication section is a BLE communication section and the second RF communication section is a UHF communication section.

[0077] 20. The method of any of statements 16-19, wherein the multiband radio frequency communication device is a TPMS sensor.

[0078] It will be understood from the foregoing description that modifications and changes may be made in various embodiments of the present disclosure without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense. The scope of the present disclosure is limited only by’ the language of the following claims.

Claims

CLAIMSWhat is claimed is:

1. A tire pressure monitoring system (TPMS) sensor comprising:a first radio frequency (RF) communication section configured to communicate in a first RF band and including a first RF circuit;a second RF communication section configured to communicate in a second RF band different from the first RF band and including a second RF circuit, a second ground plane, and an antenna operatively associated with the second ground plane;an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that signals generated by the first RF circuit are transmitted using at least part of the second RF communication section including the antenna; and one or more isolation components configured to decouple the first RF communication section from the second RF communication section such that the second RF communication section remains operable for communication in the second RF band.

2. The TPMS sensor of claim 1, wherein the first RF band is a 2.4 GHz band and the second RF band is an ultrahigh frequency (UHF) band.

3. The TPMS sensor of claim 1, wherein the first RF communication section is a Bluetooth Low Energy' (BLE) communication section.

4. The TPMS sensor of claim 1, wherein the second RF communication section further includes a second impedance matching circuit coupling an output of the second RF circuit to a first end of the antenna.

5. The TPMS sensor of claim 4, wherein a second end of the antenna is coupled to the second ground plane through a capacitor.

6. The TPMS sensor of claim 1, wherein the one or more isolation components include one or more inductors in one or more power supply connections.

7. The TPMS sensor of claim 1, wherein the signals generated by the first RF circuit are transmitted using a radiating structure that includes the second ground plane and the antenna.

8. The TPMS sensor of claim 7, wherein the radiating structure further includes one or more metallic structures of the second RF communication section.

9. A multiband radio frequency communication device comprising:a first RF communication section configured for communication in a first RF band and including a first RF circuit;a second RF communication section configured for communication in a second RF band different from the first RF band and including a second RF circuit, a second ground plane, and an antenna;a coupling network including an impedance matching circuit coupling an output of the first RF circuit to the second ground plane such that the second RF communication section provides a radiating structure for transmission of signals generated by the first RF circuit; andan isolation arrangement configured to electrically decouple the first RF communication section from the second RF communication section for high- frequency operation.

10. The multiband radio frequency communication device of claim 9. wherein the first RF band is higher than the second RF band.

11. The multiband radio frequency communication device of claim 10, wherein the first RF band is a 2.4 GHz band.

12. The multiband radio frequency communication device of claim 10, wherein the second RF band is a sub-GHz band.

13. The multiband radio frequency communication device of claim 9, wherein the radiating structure includes the second ground plane, the antenna, and one or more conductive structures of the second RF communication section.

14. The multiband radio frequency communication device of claim 9. wherein the second RF communication section remains configured to communicate in the second RF band while the first RF communication section uses the radiating structure for communication in the first RF band.

15. The multiband radio frequency communication device of claim 9. wherein the multiband radio frequency communication device is implemented in a tire-mounted sensor.

16. A method of operating a multiband radio frequency communication device, the method comprising:generating first-band RF signals in a first RF band with a first RF communication section;coupling an output of a first RF circuit of the first RF communication section to a ground plane of a second RF communication section through an impedance matching circuit, the second RF communication section being configured for communication in a second RF band different from the first RF band; andtransmitting the first-band RF signals using a radiating structure of the second RF communication section that includes an antenna associated with the second RF communication section.

17. The method of claim 16, further comprising isolating the first RF communication section from the second RF communication section using one or more isolation components.

18. The method of claim 17, further comprising communicating in the second RF band using the second RF communication section while the second RF communication section remains operable in the second RF band.

19. The method of claim 16, wherein the first RF communication section is a BLE communication section and the second RF communication section is a UHF communication section.

20. The method of claim 16, wherein the multiband radio frequency communication device is a TPMS sensor.

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