Wireless tag circuit, device and system

Abstract

The embodiment of the application provides a wireless tag circuit, device and system. The circuit comprises an antenna module, a passive coding module and a passive frequency conversion module; the antenna module and the passive frequency conversion module are electrically connected with the passive coding module; the wireless tag circuit is configured to receive a downlink radio frequency pulse signal and sequentially send a plurality of first uplink frequency conversion pulse signals with a relative time delay; wherein the carrier frequency of each first uplink frequency conversion pulse signal is different from the carrier frequency of the downlink radio frequency pulse signal.

Description

Technical Field

[0001] This application relates to the field of wireless communication, and more specifically, to wireless tag circuits, devices, and systems. Background Technology

[0002] Passive IoT technology has a wide range of applications, including but not limited to smart homes, smart transportation, smart agriculture, smart logistics, and smart healthcare. In these scenarios, passive IoT technology can enable various intelligent and automated applications, improving efficiency, reducing costs, and enhancing user experience.

[0003] Surface acoustic wave (SAW) RFID tags (SAW-RFID) have no internal electrical components; they passively reflect radio frequency signals. Therefore, SAW-RFID has a relatively long wireless communication range. However, SAW-RFID is susceptible to interference from ambient signals on the same frequency, resulting in lower accuracy in extracting the returned signal. Furthermore, SAW-RFID also faces technical challenges such as reducing tag collision rates, increasing tag encoding capacity, and lowering tag encoding costs. Utility Model Content

[0004] This application overcomes the shortcomings of the prior art by providing wireless tag circuits, devices, and systems to solve at least one of the aforementioned technical problems.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, a wireless tag circuit is provided, including an antenna module, a passive coding module, and a passive frequency conversion module; the antenna module and the passive frequency conversion module are electrically connected to the passive coding module respectively; the wireless tag circuit is configured to receive downlink radio frequency pulse signals and sequentially transmit a plurality of first uplink frequency conversion pulse signals having relative time delays with each other; wherein the carrier frequency of each first uplink frequency conversion pulse signal is different from the carrier frequency of the downlink radio frequency pulse signal.

[0007] Furthermore, the passive coding module is configured to transmit the downlink radio frequency pulse signal from the antenna module to the passive frequency conversion module, and to convert the second uplink frequency conversion pulse signal from the passive frequency conversion module into a plurality of first uplink frequency conversion pulse signals with relative time delays between them.

[0008] Furthermore, the passive frequency conversion module is configured to convert the downlink radio frequency pulse signal from the passive encoding module into a second uplink frequency conversion pulse signal, and transmit the second uplink frequency conversion pulse signal to the passive encoding module; wherein the carrier frequency of the downlink radio frequency pulse signal and the second uplink frequency conversion pulse signal are different.

[0009] Furthermore, the passive coding module includes port one, port two, filter unit one, filter unit two, filter unit three, and surface acoustic wave coding unit. Port one is electrically connected to the antenna module, and port two is electrically connected to the passive frequency conversion module. The first end of filter unit one is electrically connected to port one, and the second end of filter unit one is electrically connected to port two. The first end of filter unit two is electrically connected to port one, and the second end of filter unit two and the first end of filter unit three are respectively electrically connected to the surface acoustic wave coding unit. The second end of filter unit three is electrically connected to port two.

[0010] Furthermore, the passive coding module includes port one, port two, a circulator, and a surface acoustic wave coding unit; wherein, port one is electrically connected to the antenna module, and port two is electrically connected to the passive frequency conversion module; the first port of the circulator is electrically connected to port one, the second port of the circulator is electrically connected to port two, and the third port of the circulator is electrically connected to the surface acoustic wave coding unit.

[0011] Furthermore, the surface acoustic wave encoding unit converts the second uplink frequency conversion pulse signal into a plurality of first uplink frequency conversion pulse signals with relative time delays between them; wherein, the second uplink frequency conversion pulse signal is converted by the passive frequency conversion module based on the downlink radio frequency pulse signal.

[0012] Furthermore, the passive frequency converter module uses one of the following as the frequency conversion element: transistor, varactor diode, frequency multiplier diode, or voltage-controlled oscillator.

[0013] Furthermore, the surface acoustic wave (SAW) encoding unit includes a SAW device, which includes a piezoelectric substrate and a SAW structure fabricated on the surface of the piezoelectric substrate.

[0014] Furthermore, the surface acoustic wave structure includes a sensitive element disposed in the delay line region.

[0015] Furthermore, it also includes a sensing module, which is electrically connected to the passive frequency converter module.

[0016] Secondly, a wireless tag device is provided, which includes a housing and the aforementioned wireless tag circuit.

[0017] Thirdly, a wireless tag system is provided, including a reading device and several of the aforementioned wireless tag circuits or several of the aforementioned wireless tag devices; the reading device is used to send downlink radio frequency pulse signals to the wireless tag devices and to receive several first uplink frequency conversion pulse signals transmitted back by each wireless tag device or wireless tag circuit.

[0018] It is understandable that by setting the carrier frequency of each first uplink frequency conversion pulse to be different from the carrier frequency of the downlink radio frequency pulse, the co-channel interference problem caused by environmental scattering of the downlink radio frequency pulse in the co-channel transmission system can be effectively solved, the demodulation accuracy of the backhaul signal can be improved, the communication reliability and anti-interference capability of the wireless tag system can be enhanced, and the wireless communication distance can be extended.

[0019] It is understandable that configuring the wireless tag circuit to sequentially send a number of first uplink frequency conversion signals with relative time delays between them can, specifically, significantly increase the tag capacity within the communication coverage area of ​​the reading device, reduce the tag collision rate, and improve the access efficiency of wireless tags by encoding the relative time delays between the number of first uplink frequency conversion pulse signals. Attached Figure Description

[0020] Figure 1 This is one of the schematic diagrams of the wireless tag circuit architecture according to an embodiment of this application;

[0021] Figure 2 This is one of the schematic diagrams illustrating the configuration of a passive coding module in an embodiment of this application;

[0022] Figure 3 This is a second schematic diagram illustrating the configuration of the passive coding module in an embodiment of this application;

[0023] Figure 4 This is a schematic diagram of the surface acoustic wave encoding unit configuration in an embodiment of this application;

[0024] Figure 5 This is a second schematic diagram of the wireless tag circuit architecture according to an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0028] The terms "first," "second," "object one," "object two," etc., used in the specification and drawings of this application are used to distinguish different objects or to distinguish different treatments of the same object, rather than to describe a specific order of objects.

[0029] Furthermore, the terms "comprising" and "having," and any variations thereof, used in the description of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include other steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0030] It should be noted that in the embodiments of this application, the words "exemplary" or "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0031] For ease of understanding, the concepts and terms that may appear in this application are explained below.

[0032] Tags: Also known as electronic tags, smart tags, transponders, etc. Based on their function, they can be divided into identification tags and sensing tags. The former only provides identification functionality, while the latter provides both identification and sensing functions.

[0033] Reading device: also known as reader, transceiver, access device, gateway, base station, transceiver, communicator, reader, etc. It is typically used to read (and sometimes write) tag information. Reading devices can be mobile or fixed.

[0034] Carrier signal: A high-frequency signal that serves as the physical basis for transmitting low-frequency signals (such as voice and data). Modulation techniques can be used to modulate the baseband signal by adding modulated amplitude, frequency, or phase to create a modulated carrier signal.

[0035] Downlink: For communication between the reader and the tag, it refers to the direction of signal flow from the reader to the tag. For the tag itself, it refers to the direction of signal flow from outside the tag to inside the tag.

[0036] Uplink: In communication between the reader and the tag, it refers to the direction of signal flow from the tag to the reader. For the tag itself, it refers to the direction of signal flow from inside the tag to outside the tag.

[0037] Currently, passive IoT has become an important technology in the field of IoT. The characteristic of passive IoT technology is that the wireless tags do not require an external power cord or built-in battery. Instead, they collect micro-energy from the environment, such as wireless energy, thermal energy, vibration energy, and mechanical energy, and convert this micro-energy into electrical energy that can drive the passive tags to maintain their normal operation and realize functions such as data collection and transmission.

[0038] However, since passive tags do not actively emit signals, they can only utilize environmental energy for data collection and transmission. But environmental energy is relatively limited; therefore, passive tag systems suffer from short transmission distances due to energy constraints. Furthermore, current typical passive tag technology, RFID, employs a simultaneous uplink and downlink communication system, leading to numerous technical challenges such as short communication distances, limited tag encoding capacity, and weak anti-interference capabilities.

[0039] In view of this, this application applies passive coding technology and uplink / downlink passive frequency conversion technology to wireless tags, thereby significantly increasing the tag capacity within the communication coverage area of ​​the reading device, reducing the tag collision rate, improving the access efficiency of wireless tags, enhancing the communication reliability and anti-interference capability of the system, and extending the wireless communication distance.

[0040] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0041] Figure 1 This is a schematic diagram of a wireless tag circuit architecture provided in an embodiment of this application. Figure 1 As shown, the wireless tag circuit includes: an antenna module, a passive encoding module, and a passive frequency conversion module; the antenna module and the passive frequency conversion module are electrically connected to the passive encoding module respectively.

[0042] The wireless tag circuit is configured to receive downlink radio frequency pulse signals and sequentially transmit a plurality of first uplink frequency conversion pulse signals having relative time delays with each other; the carrier frequency of each first uplink frequency conversion pulse signal is different from the carrier frequency of the downlink radio frequency pulse signal.

[0043] It is understandable that by setting the carrier frequency of each first uplink frequency conversion pulse to be different from the carrier frequency of the downlink radio frequency pulse, the co-channel interference problem caused by environmental scattering of the downlink radio frequency pulse in the co-channel transmission system can be effectively solved, the demodulation accuracy of the backhaul signal can be improved, the communication reliability and anti-interference capability of the wireless tag system can be enhanced, and the wireless communication distance can be extended.

[0044] It is understandable that configuring the wireless tag circuit to sequentially send a number of first uplink frequency conversion signals with relative time delays between them can, specifically, significantly increase the tag capacity within the communication coverage area of ​​the reading device, reduce the tag collision rate, and improve the access efficiency of wireless tags by encoding the relative time delays between the number of first uplink frequency conversion pulse signals.

[0045] The antenna module is described below.

[0046] The antenna module is configured to receive downlink radio frequency pulse signals in free space and to transmit a first uplink frequency conversion pulse signal into free space.

[0047] It is understandable that the operating frequency band of the antenna module needs to cover the downlink RF pulse and the first uplink frequency conversion pulse signal, and its shape and principle are not limited.

[0048] In one example, the antenna module can be a planar antenna or a whip antenna; or it can be a directional antenna or an omnidirectional antenna.

[0049] The passive coding module is described below.

[0050] The passive coding module is configured to transmit the downlink radio frequency pulse signal from the antenna module to the passive frequency conversion module, and to convert the second uplink frequency conversion pulse signal from the passive frequency conversion module into a plurality of first uplink frequency conversion pulse signals with relative time delays between them.

[0051] In one implementation, such as Figure 2 As shown, Figure 2 A schematic diagram of a passive coding module is provided. The passive coding module includes port 1 P1, port 2 P2, filter unit 1, filter unit 2, filter unit 3, and surface acoustic wave (SAW) coding unit. Port 1 P1 is electrically connected to the antenna module, and port 2 P2 is electrically connected to the passive frequency conversion module. The first end of filter unit 1 is electrically connected to port 1 P1, and the second end of filter unit 1 is electrically connected to port 2 P2. The first end of filter unit 2 is electrically connected to port 1 P1, and the second end of filter unit 2 and the first end of filter unit 3 are respectively electrically connected to the SAW coding unit. The second end of filter unit 3 is electrically connected to port 2 P2.

[0052] Filter unit one is configured to allow downlink RF pulse signals to pass through while blocking uplink frequency conversion pulse signals. Filter units two and three are configured to allow uplink frequency conversion pulse signals to pass through while blocking downlink RF signals. It can be understood that the uplink frequency conversion pulse signals here include the second uplink frequency conversion pulse signal and the first frequency conversion pulse signal.

[0053] The surface acoustic wave (SAW) encoding unit is configured to convert the second uplink frequency-converted pulse signal into a plurality of first uplink frequency-converted pulse signals with relative time delays between them. The carrier frequencies of the first uplink frequency-converted pulse signals and the second uplink frequency-converted pulse signals are the same.

[0054] In another implementation, such as Figure 3 As shown, Figure 3 A schematic diagram of a passive coding module is provided. The passive coding module includes port 1 (P1), port 2 (P2), a circulator, and a surface acoustic wave (SAW) coding unit. Port 1 (P1) is electrically connected to the antenna module, and port 2 (P2) is electrically connected to the passive frequency conversion module. The first port of the circulator is electrically connected to port 1 (P1), the second port of the circulator is electrically connected to port 2 (P2), and the third port of the circulator is electrically connected to the SAW coding unit.

[0055] The circulator is used to constrain the transmission paths of the downlink radio frequency pulse signal, the first uplink frequency conversion pulse signal, and the second uplink frequency conversion pulse signal. Specifically, the downlink radio frequency pulse signal is transmitted from the first port of the circulator to the second port of the circulator, the second uplink frequency conversion pulse signal is transmitted from the second port of the circulator to the third port of the circulator, and the first uplink frequency conversion pulse signal is transmitted from the third port of the circulator to the first port of the circulator.

[0056] The surface acoustic wave (SAW) encoding unit is configured to convert the second uplink frequency-converted pulse signal into a plurality of first uplink frequency-converted pulse signals with relative time delays between them. The carrier frequencies of the first uplink frequency-converted pulse signals and the second uplink frequency-converted pulse signals are the same.

[0057] The following section introduces the surface acoustic wave coding unit.

[0058] In one embodiment, the surface acoustic wave (SAW) coding unit includes a SAW device.

[0059] Surface acoustic wave (SAW) devices are passive devices fabricated on piezoelectric substrates, comprising the piezoelectric substrate and a SAW structure fabricated on the surface of the piezoelectric substrate. For example... Figure 4As shown, surface acoustic wave (SAW) structures typically include interdigital transducers, reflective gratings, and other thin-film metal structures fabricated on piezoelectric substrates. Based on the piezoelectric effect, they achieve the energy conversion between electromagnetic waves and SAW, generating, converting, and controlling SAW to perform functions such as filtering, delaying, and sensing. They have been widely used in radar, communications, audio-visual, remote control, and sensing. The piezoelectric effect can be divided into direct piezoelectric effect and inverse piezoelectric effect. The direct piezoelectric effect refers to the phenomenon where, when a piezoelectric substrate is subjected to an external force along its mechanical axis, internal polarization occurs, generating opposite charges on two planes perpendicular to the electric axis. When the external force is removed, the piezoelectric substrate returns to its uncharged state; when the direction of the external force changes, the polarity of the generated charges also changes; the amount of charge generated by the piezoelectric substrate under force is proportional to the magnitude of the external force. Conversely, the inverse piezoelectric effect occurs when an alternating electric field is applied to the piezoelectric substrate along its electric axis, causing mechanical deformation in a plane perpendicular to the mechanical axis.

[0060] The performance of surface acoustic wave (SAW) devices is related to the piezoelectric substrate, interdigital transducer, and reflector grating. SAW devices with specific frequency ranges and amplitudes can be obtained by designing the piezoelectric substrate, interdigital transducer, and reflector grating. Existing design methods can be used to achieve this; for example, relevant design methods include mode coupling (COM) and scattering matrix methods (p-matrix). This application does not limit the specific design methods.

[0061] In one example, the piezoelectric substrate is made of lithium niobate, lithium tantalate, or quartz.

[0062] In one example, the interdigital transducer may be a uniform interdigital transducer, an apodization interdigital transducer, or a withdrawn interdigital transducer.

[0063] Among them, the uniform interdigital transducer is the most basic and simplest interdigital transducer structure. All its fingers have the same width and spacing, and the overlap length or aperture of all finger pairs is also exactly the same. It has a wide operating bandwidth.

[0064] An apodization interdigital transducer maintains uniform and equal width and spacing of the finger strips along its entire length, but the length of each finger pair varies. This type of interdigital transducer performs amplitude weighting by changing the overlap length of the finger pairs along the direction of sound wave propagation. It exhibits good sidelobe suppression.

[0065] The withdrawable interdigital transducer achieves weighting by selectively deleting or removing certain fingers from a uniform interdigital transducer, while the retained fingers maintain their original width and spacing. Its key characteristic is that the fingers are not spatially continuous but rather regularly missing. By deleting fingers, the density or spatial sampling of the finger distribution is altered. Its sidelobe suppression effect is better than that of a uniform interdigital transducer but inferior to that of an apodization interdigital transducer, but it can suppress certain specific sidelobes, especially those caused by periodicity.

[0066] In one embodiment, the surface acoustic wave device includes a plurality of reflective gratings operating at the same frequency.

[0067] Typically, a reflector grating consists of a periodically arranged array of metal gratings. Surface acoustic waves (SAWs) undergo mechanical reflection at the grating due to discontinuities in acoustic impedance. Commonly used reflector grating types include interdigitated gratings, short-circuit gratings, open-circuit gratings, and positive-negative gratings. The characteristics of an interdigitated grating can be altered by an external load, creating an impedance-loaded device. In a short-circuit grating, all gratings are connected in parallel via busbars, resulting in identical voltage across all electrodes. In an open-circuit grating, each grating is relatively independent, and no current flows within the electrodes. Positive-negative gratings are formed by alternating arrangements of open-circuit and short-circuit gratings.

[0068] In one example, the width and spacing of the grating bars are both equal to one-quarter of the wavelength of the surface acoustic wave. The reflected echoes satisfy Bragg's theorem, and the reflected echoes from each grating bar are superimposed in phase, at which point the echo signal energy is maximized.

[0069] like Figure 4 As shown, the surface acoustic wave (SAW) device includes a piezoelectric substrate and a SAW structure fabricated on the surface of the piezoelectric substrate. The SAW structure includes port 3 (P3), a transducer region, a delay line region, and an encoding region. The delay line region is located between the transducer region and the encoding region. The encoding region includes several encoding bits, each with the same width, thus ensuring that the time delay values ​​between adjacent encoding bits are identical. The transducer region includes interdigital transducers, which include bus bar 1 and bus bar 2. Bus bar 1 is electrically connected to port 3 (P3), and bus bar 2 is grounded. The encoding region includes several reflective gratings operating at specific frequencies, each located at a different position within the encoding region. This allows for the reflection of broadband SAW waves from the transducer region at several specific frequencies with different time delays, thereby achieving time-frequency encoding of the tag circuit. Therefore, by simultaneously encoding the time delay values ​​of the SAW waves reflected by each tag (correspondingly, also to the first uplink frequency conversion signal), different encodings for each wireless tag can be achieved, reducing the collision rate and increasing the wireless tag capacity.

[0070] Understandable, Figure 2 In the context of surface acoustic wave coding units, when... Figure 4 When the structure is , Figure 4 Port 3 P3 of the surface acoustic wave device is electrically connected to port 2 of filter unit 2 and port 1 of filter unit 3, respectively.

[0071] Understandable, Figure 3 In the context of surface acoustic wave coding units, when... Figure 4 When the structure is , Figure 4 The third port P3 of the surface acoustic wave device is electrically connected to the third port of the circulator.

[0072] It is understandable that the reflective grating can be designed to reflect only surface acoustic waves of a specific frequency by designing the characteristic parameters of the reflective grating (such as grating width, spacing between grating electrodes, grating type, grating electrode material, etc.).

[0073] In another embodiment, the surface acoustic wave coding unit has both passive coding and sensing functions.

[0074] For details, please refer to Figure 4 It also includes a sensitive element disposed in the delay line region. The sensitive element is used to sense changes in the target parameter, thereby causing changes in the geometry and / or characteristic parameters of the delay line region, which in turn causes a change in the carrier frequency of the first uplink frequency-converted pulse signal. That is, the sensitive element maps the sensed quantity to the carrier frequency of the first uplink frequency-converted pulse signal, and the sensed quantity can be obtained in reverse by analyzing the carrier frequency. The specific type of the sensitive element is not limited; for example, the sensed parameters of the sensitive element include, but are not limited to, temperature, humidity, pressure, vibration, and dielectric constant.

[0075] The following section provides a detailed introduction to the high-capacity, low-cost encoding method for surface acoustic wave (SAW) devices.

[0076] As mentioned earlier, by encoding the time delay value of the surface acoustic wave reflected by each tag (correspondingly, also to the first uplink frequency conversion signal), different encodings can be achieved for each wireless tag, reducing the collision rate and increasing the wireless tag capacity.

[0077] In one embodiment, for the same tag, the coding area of ​​the surface acoustic wave device of the tag can be provided with several reflective gratings operating at the same frequency at different coding bits. The number of coding bits is greater than the number of reflective gratings.

[0078] In one example, the number of coded bits is more than twice the number of reflective gratings.

[0079] In one implementation, for different tags, at least one common coding bit in the surface acoustic wave (SAW) devices of each pair of tags has a different setting. It is understood that "different setting" here refers to the setting of the reflective grating in the coding bit; for example, in the fifth coding bit of two tags, one tag has a reflective grating, while the other tag does not.

[0080] It is understood that, in any of the foregoing embodiments, in order to reduce the return of unreflected surface acoustic waves to the transducer region, a surface acoustic wave absorber can be provided at the tail end of the coding region, such as... Figure 4 As shown by the black bar at the right end of the middle.

[0081] It is understood that, in any of the foregoing embodiments, a surface acoustic wave absorber may also be provided on the side of the transducer away from the encoding area to eliminate unnecessary surface acoustic wave reflections back to the transducer, such as... Figure 4 As shown by the black bar on the left.

[0082] The following section introduces the passive frequency converter module.

[0083] The passive frequency converter module is configured to convert the downlink radio frequency pulse signal from the passive encoding module into a second uplink frequency conversion pulse signal, and transmit the second uplink frequency conversion pulse signal to the passive encoding module; wherein the carrier frequency of the downlink radio frequency pulse signal and the second uplink frequency conversion pulse signal are different.

[0084] The passive frequency converter module can adopt various passive frequency converter schemes that can achieve the above functions, and this application does not impose any restrictions. For example, the passive frequency converter module uses one of the following as the frequency conversion element: transistor, varactor diode, frequency multiplier diode, and voltage-controlled oscillator.

[0085] In one example, the passive frequency converter module includes a transistor, a first resonant circuit, and a second resonant circuit, which are electrically connected to the transistor, respectively. Example circuit structures can be found in: Prior Art 1 (Application No.: 202310112908.0, Title: A Passive Frequency Converter Structure and Passive Frequency Converter Method), Prior Art 2 (Application No.: 202411053036.6, Title: A Passive Frequency Converter Structure, Sensor, Method, and System), and Prior Art 3 (Application No.: 202411270397.6, Title: Communication Circuit, Method, Apparatus, and System).

[0086] In one example, the passive frequency conversion module includes a varactor diode and a resonant network, with the resonant network electrically connected to the varactor diode. An example circuit structure can be found in: Prior Art 4 (Application No.: 202410734655.5, Title: A Passive Wireless Sensor Based on Two Reverse-Connected Varactor Diodes).

[0087] In one example, the passive frequency converter module includes a frequency multiplier diode.

[0088] In one example, the passive frequency conversion module includes a voltage-controlled oscillator. An example circuit structure can be found in: Prior Art 5 (Application No.: 201910593590.6, Title: A Multifunctional Integrated Wireless Sensor Component and Detection Method).

[0089] The following section introduces another wireless tag circuit that combines identification and sensing functions.

[0090] like Figure 5 As shown, in Figure 1 Based on this, the wireless tag circuit also includes a sensing module, which is electrically connected to the passive frequency conversion module. The sensing module detects changes in the target object's parameters and adjusts the carrier frequency of the second uplink frequency conversion pulse signal output by the passive frequency conversion module based on the detected values. During demodulation, the magnitude of the detected values ​​can be determined by referring to the preset mapping relationship between the carrier frequency and the detected values.

[0091] This application also provides a wireless tag device, which includes a housing and the wireless tag circuit disclosed in any of the foregoing embodiments. All or part of the wireless tag circuit is disposed inside the housing, which protects the wireless tag circuit to improve its mechanical performance, environmental performance, and service life.

[0092] In one example, the wireless tag circuitry is entirely housed inside the housing, and the housing is made of a wave-transparent material at least at the locations corresponding to the antenna module.

[0093] In one example, the antenna module of the wireless tag circuit is located outside the housing, while other modules are located inside the housing. The housing has a communication interface that is electrically connected to the antenna module.

[0094] This application also provides a wireless tag system, which includes a reading device and the aforementioned plurality of wireless tag devices, wherein the reading device is used to send downlink radio frequency pulse signals to each wireless tag device and to receive a plurality of first uplink frequency conversion pulse signals transmitted back by each wireless tag device, wherein the carrier frequency of the downlink radio frequency pulse signals is different from that of the first uplink frequency conversion pulse signals.

[0095] Although this application has been described herein with reference to illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of this application, various variations and improvements can be made to the components and / or layout of the subject matter combination layout. Besides variations and improvements to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A wireless tag circuit, characterized in that, It includes an antenna module, a passive coding module, and a passive frequency conversion module; the antenna module and the passive frequency conversion module are electrically connected to the passive coding module respectively; The wireless tag circuit is configured to receive downlink radio frequency pulse signals and sequentially transmit a plurality of first uplink frequency conversion pulse signals having relative time delays with each other; wherein the carrier frequency of each of the first uplink frequency conversion pulse signals is different from the carrier frequency of the downlink radio frequency pulse signals. The passive coding module includes port one, port two, filter unit one, filter unit two, filter unit three, and surface acoustic wave coding unit. Port one is electrically connected to the antenna module, and port two is electrically connected to the passive frequency conversion module. The first end of filter unit one is electrically connected to port one, and the second end of filter unit one is electrically connected to port two. The first end of filter unit two is electrically connected to port one, and the second end of filter unit two and the first end of filter unit three are respectively electrically connected to the surface acoustic wave coding unit. The second end of filter unit three is electrically connected to port two.

2. The circuit according to claim 1, characterized in that, The passive encoding module is configured to transmit the downlink radio frequency pulse signal from the antenna module to the passive frequency conversion module, and to convert the second uplink frequency conversion pulse signal from the passive frequency conversion module into a plurality of first uplink frequency conversion pulse signals with relative time delays between them.

3. The circuit according to claim 1, characterized in that, The passive frequency conversion module is configured to convert the downlink radio frequency pulse signal from the passive encoding module into a second uplink frequency conversion pulse signal, and transmit the second uplink frequency conversion pulse signal to the passive encoding module; wherein the carrier frequency of the downlink radio frequency pulse signal and the second uplink frequency conversion pulse signal are different.

4. The circuit according to claim 1, characterized in that, The passive coding module includes port one, port two, a circulator, and a surface acoustic wave (SAW) coding unit; wherein, port one is electrically connected to the antenna module, and port two is electrically connected to the passive frequency conversion module; the first port of the circulator is electrically connected to port one, the second port of the circulator is electrically connected to port two, and the third port of the circulator is electrically connected to the SAW coding unit.

5. The circuit according to claim 1 or 4, characterized in that, The surface acoustic wave encoding unit converts the second uplink frequency conversion pulse signal into a plurality of first uplink frequency conversion pulse signals with relative time delays between them; wherein, the second uplink frequency conversion pulse signal is converted by the passive frequency conversion module based on the downlink radio frequency pulse signal.

6. The circuit according to claim 1 or 3, characterized in that, The passive frequency converter module uses one of the following as the frequency conversion element: transistor, varactor diode, frequency multiplier diode, or voltage-controlled oscillator.

7. The circuit according to claim 3 or 4, characterized in that, The surface acoustic wave (SAW) encoding unit includes a SAW device, which includes a piezoelectric substrate and a SAW structure fabricated on the surface of the piezoelectric substrate.

8. The circuit according to claim 7, characterized in that, The surface acoustic wave structure includes a sensitive element disposed in the delay line region.

9. The circuit according to claim 1, characterized in that, It also includes a sensing module, which is electrically connected to the passive frequency converter module.

10. A wireless tag device, characterized in that, It includes a housing and the wireless tag circuitry as described in any one of claims 1-9.

11. A wireless tag system, characterized in that, The device includes a reading device and several wireless tag circuits as described in any one of claims 1-9 or several wireless tag devices as described in claim 10; the reading device is used to send downlink radio frequency pulse signals to the wireless tag device and to receive several first uplink frequency conversion pulse signals transmitted back by each wireless tag device or wireless tag circuit.

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