Time-division multiplexing matching system for RF energy harvesting and wake-up receivers

Abstract

The present invention provides a time-division multiplexing matching system for radio frequency energy harvesting and waking up a receiver, comprising: an antenna for receiving two radio frequency signals, 915 MHz and 434 MHz; an impedance matching network for adjusting the characteristic impedance of the radio frequency signal and ensuring that the matched signal can be passively amplified; an RF-DC converter (RF-DC) unit for harvesting radio frequency energy; a wake-up receiver (WuRX) unit for monitoring environmental signals and outputting a wake-up signal; a control module in the WuRX unit for outputting a control signal to control a blocking-conduction switch, thereby adjusting the impedance of the RF-DC converter (RF-DC) unit and the WuRX unit for signal gating; and alternating operation of the RF energy harvester and the wake-up receiver to achieve time-division multiplexing of the antenna and the matching network.

Description

Technical Field

[0001] The present invention relates to the field of microelectronics technology, and in particular to a time-division multiplexing matching system for collecting radio frequency energy and waking up a receiver. Background Art

[0002] With the rapid development of integrated circuits and 5G communication networks, the Internet of Things (IoT) industry has ushered in unprecedented growth opportunities, transitioning from concept to large-scale application. By deploying a large number of wireless sensor networks (WSNs), the IoT collects and transmits a wide range of environmental data, enabling the "Internet of Everything." However, with the surge in the number of IoT nodes, efficiently managing their energy consumption, particularly reducing energy waste during non-communication, has become a critical issue that needs to be addressed.

[0003] To reduce energy consumption in IoT nodes, wake-up receiver (WuRX) technology has emerged. WuRX significantly reduces unnecessary energy consumption by putting the main transceiver into a dormant state when communication is not required, activating it only upon receiving a specific wake-up signal. This technology effectively extends the battery life of the node and improves the overall energy efficiency of the system. With the expansion of modern communication networks, the environment is filled with abundant RF energy, providing a potential energy source for IoT nodes. Some research has begun exploring the combination of RF energy harvesting and wake-up receiver technology to further optimize node energy management. RF energy harvesting can extract energy from wireless signals in the environment to power IoT nodes, reducing reliance on external power sources.

[0004] Although wake-up receiver technology and RF energy harvesting have achieved significant results in reducing the energy consumption of IoT nodes, existing solutions still have some shortcomings. On the one hand, the simultaneous implementation of RF energy harvesting and wake-up receiver functions usually requires two independent systems, including their own antennas and matching networks. This not only increases system complexity and cost, but also limits the miniaturization and high integration of WSN nodes. On the other hand, the efficiency of existing RF energy harvesting is low, especially in low-power density environments, making it difficult to meet the continuous operation requirements of IoT nodes. Therefore, how to achieve a high degree of integration of RF energy self-powering and wake-up receiver functions while ensuring system robustness and sensitivity has become a key and difficult issue in current research. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a time-division multiplexing matching system for radio frequency energy collection and wake-up receiver.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] The present invention provides a time-division multiplexing matching system for radio frequency energy collection and receiver wake-up, comprising:

[0008] The antenna is used to receive radio frequency signals;

[0009] The impedance matching network is connected to the antenna and is used to perform impedance matching on the received radio frequency signal so that the impedance of the time-division multiplexing matching system is equal to the impedance of the antenna;

[0010] The blocking-conducting switch is connected to the output end of the impedance matching network and is used as a switching element to adjust the impedance of the RF-DC unit and the wake-up receiver WuRX unit according to the internal enable signal to obtain the RF adjustment signal;

[0011] The RF-DC unit is connected to the blocking-conducting switch and is used to convert the RF adjustment signal into DC power to power the wake-up receiver WuRX unit;

[0012] The wake-up receiver WuRX unit is connected to the blocking-conduction switch and is configured to be woken up when receiving a radio frequency adjustment signal of a preset frequency;

[0013] Among them, the blocking-conduction switch performs impedance adjustment based on tunable RF switch technology to achieve time-sharing multiplexing of RF energy collection and awakening the receiver WuRX unit.

[0014] Optionally, the blocking-conducting switch includes: a PMOS transistor M1, a PMOS transistor M2, an adjustable capacitor C IN_W and adjustable capacitor C IN_R ;

[0015] The source of the PMOS transistor M1 is connected to the RF-DC unit and the adjustable capacitor C IN_R The upper plate connection;

[0016] The source of the PMOS transistor M2 is connected to the wake-up receiver WuRX unit and the adjustable capacitor C IN_W The lower plate connection;

[0017] Adjustable capacitor C IN_R The lower plate and adjustable capacitor C IN_W The upper plates are connected to each other and grounded;

[0018] The drain of the PMOS transistor M1, the drain of the PMOS transistor M2, and the output end of the impedance matching network are connected to each other;

[0019] The gate of the PMOS transistor M1 is connected to the internal enable signal EN_RFDC; the gate of the PMOS transistor M2 is connected to the internal enable signal EN_WuRX;

[0020] The internal enable signal EN_RFDC and the internal enable signal EN_WuRX are both outputted by waking up the control module in the receiver WuRX unit.

[0021] Optionally, the blocking-conducting switch controls the impedance of the RF-DC unit and the wake-up receiver WuRX unit respectively by adjusting the gate voltages of the PMOS transistor M1 and the PMOS transistor M2.

[0022] Optionally, the impedance matching network is a π-type matching network;

[0023] The π-type matching network includes capacitor C1, capacitor C2 and inductor L1;

[0024] One end of the inductor L1 is connected to the antenna and the upper plate of the capacitor C1 respectively; the other end of the inductor L1 is connected to the output end of the π-type matching network and the upper plate of the capacitor C2 respectively;

[0025] The lower plate of the capacitor C1 and the lower plate of the capacitor C2 are connected to each other and grounded.

[0026] Optionally, during the RF energy collection phase of the RF-DC unit, the internal enable signal EN_WuRX is high, the internal enable signal EN_RFDC is low, and the adjustable capacitor C IN_W and adjustable capacitor C IN_R is at a first preset value, so that the on-resistance of the PMOS transistor M2 is greater than that of the PMOS transistor M1, and the RF regulation signal flows to the RF-DC unit;

[0027] In the wake-up phase of the receiver WuRX unit, the internal enable signal EN_WuRX is low, the internal enable signal EN_RFDC is high, and the adjustable capacitor C IN_W and adjustable capacitor C IN_R Both are at the second preset value, so that the on-resistance of the PMOS transistor M2 is smaller than that of the PMOS transistor M1, and the RF adjustment signal flows to the wake-up receiver WuRX unit.

[0028] Optionally, the time-division multiplexing matching system for RF energy collection and receiver wake-up further includes: an energy storage capacitor C S and low dropout signal regulator LDO;

[0029] The RF-DC unit is connected to the energy storage capacitor C S And the low voltage dropout signal regulator LDO provides a stable DC voltage for the wake-up receiver WuRX unit.

[0030] Optionally, the blocking-conduction switch is specifically configured by adjusting the width-to-length ratio of the PMOS transistor M1 and the PMOS transistor M2, the value of the internal enable signal EN_RFDC, the value of the internal enable signal EN_WuRX, the adjustable capacitor C IN_W and adjustable capacitor C IN_R The capacitance value is set to achieve impedance adjustment.

[0031] The beneficial effects of the present invention are:

[0032] 1. By adopting tunable RF switch technology, time-division multiplexing of RF energy harvesting and wake-up receiver WuRX units is achieved, improving the energy efficiency and integration of the time-division multiplexing matching system.

[0033] 2. The impedance matching network adopts a π-type matching network structure design, which simplifies the complexity of the impedance matching network while ensuring good frequency selection and filtering performance.

[0034] 3. By adjusting the gate voltage of the blocking-conducting switch and the capacitance of the adjustable capacitor, impedance matching for signals in different frequency bands can be achieved, thereby improving the flexibility and application range of the time-division multiplexing matching system.

[0035] 4. Since the time-division multiplexing matching system can realize time-division reception of two radio frequency signals of different frequencies, the energy efficiency and reliability of the time-division multiplexing matching system are further improved.

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic structural diagram of a time-division multiplexing matching system for collecting radio frequency energy and waking up a receiver provided by an embodiment of the present invention;

[0038] Figure 2 A schematic diagram showing the connection relationship of a time-division multiplexing matching system for collecting radio frequency energy and waking up a receiver is shown as an example;

[0039] Figure 3 The figure shows, by way of example, the transient simulation signals output by each module in the WuRX unit of the wake-up receiver;

[0040] Figure 4 The S11 parameter of the impedance matching network is shown as an example when the RF signal is 434 MHz;

[0041] Figure 5 The S11 parameter of the impedance matching network is shown as an example when the RF signal is 915 MHz;

[0042] Figure 6The transient voltage simulation results of the impedance matching network when the RF signal is 434 MHz are shown as an example;

[0043] Figure 7 The transient voltage simulation results of the impedance matching network when the RF signal is 915 MHz are shown as an example. DETAILED DESCRIPTION

[0044] Among existing research proposals for self-powered wake-up receivers, some use a single matching network to wake up the WuRX unit. However, a single matching network typically only provides optimal matching within a specific frequency or frequency band. If operation is required across multiple frequencies or frequency bands, a single matching network cannot simultaneously meet the impedance matching requirements at all frequencies, resulting in low energy harvesting efficiency. Moreover, once a single matching network is designed, its impedance matching characteristics are fixed. In practical applications, if the operating frequency changes or if support for multiple frequency bands is required, the single matching network cannot be flexibly adjusted, limiting the system's adaptability and application scope. Some research has also adopted dual-band impedance matching networks (enabling dual-band signal acquisition by adjusting the corresponding impedance of the circuit). However, using MOSFETs as switches can achieve dual-band signal acquisition to a certain extent, but the MOSFETs generate additional losses during their on- and off-states under high-frequency signals, affecting the overall system efficiency. Furthermore, when the MOSFET is off, it cannot completely block high-frequency signals from passing through, which may cause RF signal leakage, affecting the system's impedance matching and energy harvesting efficiency. Furthermore, achieving dual-band impedance matching requires complex circuit design and precise parameter adjustment, increasing design difficulty and cost. Furthermore, matching multiple frequency points requires more circuit components, increasing system complexity and size.

[0045] Based on the shortcomings of the existing technology, the present invention provides a time-sharing multiplexing matching system for RF energy harvesting and waking up the receiver. The system adopts tunable RF switching technology. By failing the impedance matching at a specific frequency, the impedance matching network loses its passive amplification effect, thereby shutting down the RF signal and realizing time-sharing multiplexing of the RF energy harvesting and wake-up receiver WuRX unit. Since support for multiple frequency bands can be achieved through a simple switching mechanism, the circuit design is simplified, the cost and volume are reduced, and the energy efficiency and integration of the time-sharing multiplexing matching system are improved.

[0046] Specifically, the impedance failure is achieved by changing the impedance of the signal path in the blocking-conducting switch, that is, adjusting the gate voltage of the blocking-conducting switch and the capacitance value of the adjustable capacitor.

[0047] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0048] In order to achieve high integration of RF energy self-powering and wake-up receiving functions while ensuring robustness and sensitivity, an embodiment of the present invention provides a time-division multiplexing matching system for RF energy harvesting and wake-up receiver. Figure 1 The present invention provides a schematic diagram of a time-division multiplexing matching system for collecting radio frequency energy and waking up a receiver. Figure 1 Shown, including:

[0049] The antenna is used to receive radio frequency signals;

[0050] The impedance matching network is connected to the antenna and is used to perform impedance matching on the received radio frequency signal so that the impedance of the time-division multiplexing matching system is equal to the impedance of the antenna;

[0051] The blocking-conducting switch is connected to the output end of the impedance matching network and is used as a switching element to adjust the impedance of the RF-DC unit and the wake-up receiver WuRX unit according to the internal enable signal to obtain the RF adjustment signal;

[0052] The RF-DC unit is connected to the blocking-conducting switch and is used to convert the RF adjustment signal into DC power to power the wake-up receiver WuRX unit;

[0053] The wake-up receiver WuRX unit is connected to the blocking-conduction switch and is configured to be woken up when receiving a radio frequency adjustment signal of a preset frequency;

[0054] Among them, the blocking-conduction switch performs impedance adjustment based on tunable RF switch technology to achieve time-sharing multiplexing of RF energy collection and awakening the receiver WuRX unit.

[0055] In addition, if Figure 1 As shown, the wake-up receiver WuRX unit specifically integrates differential ED, baseband circuit and control module, and performs specific tasks through collaborative cooperation.

[0056] It should be noted that, in the embodiment of the present invention, the radio frequency signal can specifically be two radio frequency signals of 915MHz and 434MHz. The impedance matching network is a key part connecting the antenna and the subsequent circuit, which is mainly used to achieve matching between the antenna impedance and the impedance of the digital temperature compensation system (or other subsequent circuits). In the radio frequency circuit, impedance matching is crucial because it can ensure the effective transmission of the radio frequency signal while reducing or avoiding the reflection and energy loss of the radio frequency signal. When the radio frequency signal received by the antenna passes through the impedance matching network, the impedance matching network can adjust the impedance of the radio frequency signal to match it with the impedance of the subsequent circuit, thereby achieving efficient transmission of the radio frequency signal.

[0057] Figure 2The following is a schematic diagram showing the connection relationship of a time-division multiplexing matching system for collecting radio frequency energy and waking up a receiver. Figure 2 As shown, the blocking-conducting switch includes: a PMOS transistor M1, a PMOS transistor M2, an adjustable capacitor C IN W and adjustable capacitor C IN R ;

[0058] The source of the PMOS transistor M1 is connected to the RF-DC unit and the adjustable capacitor C IN_R The upper plate connection;

[0059] The source of the PMOS transistor M2 is connected to the wake-up receiver WuRX unit and the adjustable capacitor C IN_W The lower plate connection;

[0060] Adjustable capacitor C IN_R The lower plate and adjustable capacitor C IN_W The upper plates are connected to each other and grounded;

[0061] The drain of the PMOS transistor M1, the drain of the PMOS transistor M2, and the output end of the impedance matching network are connected to each other;

[0062] The gate of the PMOS transistor M1 is connected to the internal enable signal EN_RFDC; the gate of the PMOS transistor M2 is connected to the internal enable signal EN_WuRX;

[0063] Adjustable capacitor C IN_R It is a binary weighted adjustable capacitor array, including four controllable switches TR[3], TR[2], TR[1] and TR[0], and capacitors 8C connected to them respectively. R 、4C R , 2C R and C R One end of each switch is connected to the upper plate of the corresponding capacitor, and the other end is connected to the common node and acts as an adjustable capacitor C IN_R Upper plate, capacitor 8C R 、4C R , 2C R and C R The lower plate is connected to the common node and acts as an adjustable capacitor C IN_R Similarly, the adjustable capacitor C IN_W It includes four controllable switches TW[3], TW[2], TW[1] and TW[0], and capacitors 8C connected to them respectively. W 、4C W , 2C W and C WOne end of each switch is connected to the upper plate of the corresponding capacitor, and the other end is connected to the common node and acts as an adjustable capacitor C IN_W Upper plate, capacitor 8C W 、4C W , 2C W and C W The lower plate is connected to the common node and acts as an adjustable capacitor C IN_W The lower plate.

[0064] The internal enable signal EN_RFDC and the internal enable signal EN_WuRX are both outputted by waking up the control module in the receiver WuRX unit.

[0065] It is understood that in the embodiments of the present invention, the blocking-conducting switch designed based on the impedance characteristics of the matching system can achieve both signal transmission and shielding. This solves the problem of conventional MOS transistors having difficulty shutting off RF signals, avoids the need for RF switches, and significantly saves chip area.

[0066] The impedance matching network is a π-type matching network;

[0067] The π-type matching network includes capacitor C1, capacitor C2 and inductor L1;

[0068] One end of the inductor L1 is connected to the antenna and the upper plate of the capacitor C1 respectively; the other end of the inductor L1 is connected to the output end of the π-type matching network and the upper plate of the capacitor C2 respectively;

[0069] The lower plate of the capacitor C1 and the lower plate of the capacitor C2 are connected to each other and grounded.

[0070] It should be noted that, in the embodiment of the present invention, since the source impedance and the load impedance may not be equal, this will lead to reflection of the RF signal and energy loss. By adjusting the values ​​of capacitor C1, capacitor C2 and inductor L1 in the π-type matching network, the input impedance and the output impedance can be made equal, thereby achieving impedance matching. This helps to maximize power transmission, reduce reflections, and improve the overall performance of the time-division multiplexing matching system. In addition, the π-type matching network also has a good filtering effect. Since capacitor C1 is located on the input side, it is used to limit the voltage rise rate at the moment of power-on and filter out the ripple introduced by the power supply (antenna). Capacitor C2 is located on the output side, which not only completes the decoupling and ripple filtering functions, but also maintains the filtered level from being affected by the back electromotive force. Inductor L1 plays a role in suppressing the current change rate, which helps to reduce interference and noise of the RF signal. Therefore, in the embodiment of the present invention, the π-type matching network also acts as a filter to filter out unnecessary frequency components, making the RF signal purer.

[0071] Optionally, the blocking-conducting switch controls the impedance of the RF-DC unit and the wake-up receiver WuRX unit respectively by adjusting the gate voltages of the PMOS transistor M1 and the PMOS transistor M2.

[0072] Optionally, during the RF energy collection phase of the RF-DC unit, the internal enable signal EN_WuRX is high, the internal enable signal EN_RFDC is low, and the adjustable capacitor C IN_W and adjustable capacitor C IN_R is at a first preset value, so that the on-resistance of the PMOS transistor M2 is greater than that of the PMOS transistor M1, and the RF regulation signal flows to the RF-DC unit;

[0073] In the wake-up phase of the receiver WuRX unit, the internal enable signal EN_WuRX is low, the internal enable signal EN_RFDC is high, and the adjustable capacitor C IN_W and adjustable capacitor C IN_R Both are at the second preset value, so that the on-resistance of the PMOS transistor M2 is smaller than that of the PMOS transistor M1, and the RF adjustment signal flows to the wake-up receiver WuRX unit.

[0074] It should be noted that, in this embodiment, the sizes of the first preset value and the second preset value can be obtained through a pre-simulation process.

[0075] For example, the blocking-conducting switch needs to determine the size of the PMOS transistor M1, the size of the PMOS transistor M2, the adjustable capacitor C IN_R The size and adjustable capacitor C IN_W When collecting RF energy, the resistance is adjusted by adjusting the width-to-length ratio of the PMOS transistor M1 and the value of the internal control signal EN_RFDC. IN_R The size of the capacitor is adjusted until the impedance condition at 915MHz is met; similarly, when the receiver WuRX unit is awakened, the resistance is adjusted by adjusting the width-to-length ratio of the PMOS transistor M2 and the value of the internal control signal EN_WuRX. IN_W The size of the capacitor is adjusted to achieve the impedance condition at 434MHz.

[0076] During the RF energy collection phase of the RF-DC unit, the control signal EN_WuRX output by the wake-up receiver WuRX unit is high, so that the signal path where the PMOS transistor M2 is located is in a high impedance state, and the internal control signal TW[3:0] output by the wake-up receiver WuRX unit adjusts the adjustable capacitor C IN_W, so that this path does not meet the impedance matching requirements of 434MHz and 915MHz, and the impedance matching network cannot achieve passive amplification of the RF signal, and is in a blocked state; the internal control signal EN_RFDC output by the wake-up receiver WuRX unit is low, so that the signal path where the PMOS transistor M1 is located is in a low-impedance state, and the control signal TR[3:0] output by the wake-up receiver WuRX unit adjusts the adjustable capacitor C IN_R , since the size of the PMOS transistor M1 is adjusted by the resistor, the adjustable capacitor C IN_R After capacitor adjustment, this path meets the impedance matching requirements of 915 MHz. The 915 MHz RF signal flows to the RF-DC unit after passive amplification by the impedance matching network.

[0077] During the working phase of the wake-up receiver WuRX unit, the control signal EN_RFDC output by the wake-up receiver WuRX unit is high potential, so that the signal path where the PMOS transistor M1 is located is in a high impedance state, and the internal control signal TR[3:0] output by the wake-up receiver WuRX unit adjusts the adjustable capacitor C IN_R , so that this path does not meet the impedance matching requirements of 434MHz and 915MHz, and the impedance matching network cannot achieve passive amplification of the RF signal, and is in a blocked state; the control signal EN_WuRX output by the wake-up receiver WuRX unit is low potential, so that the signal path where the PMOS transistor M2 is located is in a low impedance state, and the control signal TW[3:0] output by the wake-up receiver WuRX unit adjusts the adjustable capacitor C IN_W , since the size of the PMOS transistor M2 is adjusted by the resistor, the adjustable capacitor C IN_W After capacitor adjustment, this path meets the impedance matching requirements of 434MHz. The 434MHz RF signal flows to the wake-up receiver WuRX unit after passive amplification by the impedance matching network.

[0078] Optionally, the time-division multiplexing matching system for RF energy collection and receiver wake-up further includes: an energy storage capacitor C S and low dropout signal regulator LDO;

[0079] The RF-DC unit is connected to the energy storage capacitor C S And the low voltage dropout signal regulator LDO provides a stable DC voltage for the wake-up receiver WuRX unit.

[0080] It should be noted that, in the embodiment of the present invention, the energy storage capacitor C S It is mainly used to store DC power converted from RF signals. The RF-DC unit can convert the received RF signal into DC voltage, but due to the intermittent and unstable nature of the RF signal, the output DC voltage will also fluctuate, and the energy storage capacitor CS These voltage fluctuations can be smoothed to ensure that the time-division multiplexing matching system can still provide stable power when the RF signal is weak or interrupted. S When the output voltage of the RF-DC converter drops, the stored charge is released, thereby maintaining the stability of the output voltage. This is particularly important for circuits such as the wake-up receiver WuRX unit that require high voltage stability.

[0081] LDO specifically uses a feedback loop to control the conduction level of the corresponding adjustment transistor to adjust the output voltage. When the output voltage attempts to rise, the feedback loop will reduce the conduction level of the adjustment transistor, thereby lowering the output voltage; conversely, when the output voltage attempts to fall, the feedback loop will increase the conduction level of the adjustment transistor, thereby increasing the output voltage, thereby providing a stable DC voltage for the wake-up receiver WuRX unit. S and LDO regulation can be specifically participated by Figure 1 It is controlled by switches S1 and S2.

[0082] Therefore, in the embodiment of the present invention, by setting the energy storage capacitor C S The low-dropout signal regulator LDO not only improves the energy utilization efficiency of the time-division multiplexing matching system, but also enhances the robustness and reliability of the time-division multiplexing matching system, making the application of RF energy harvesting and wake-up receiver WuRX unit in IoT nodes more feasible and efficient.

[0083] Optionally, the blocking-conduction switch is specifically configured by adjusting the width-to-length ratio of the PMOS transistor M1 and the PMOS transistor M2, the value of the internal enable signal EN_RFDC, the value of the internal enable signal EN_WuRX, the adjustable capacitor C IN_W and adjustable capacitor C IN_R The capacitance value is set to achieve impedance adjustment.

[0084] In order to illustrate the effectiveness of the time-division multiplexing matching system for radio frequency energy collection and receiver wake-up provided by the embodiment of the present invention. Figure 3 The example shows the transient simulation signals output by each module in the WuRX unit of the wake-up receiver. The input signal is designed to be a 915MHz signal with a power of -35dBm and a 434MHz signal with a power of -55dBm, with an alternating input period of 160ms. At the same time, the wake-up signal is set to "10101100", and the duration of each digital code is 20ms. Figure 3As can be seen, the OOK signal "10101100" uses a data transmission rate of 50bps. The signal is input into the wake-up receiver WuRX unit. After the RF signal is amplified by the impedance matching network, it is detected by the envelope detector to obtain the positive and negative envelopes of the OOK signal. The sampling clock period is 5ms (i.e., 4 times oversampling). After amplification and comparison by the baseband circuit, the correct wake-up code is demodulated. The obtained signal is sampled by the digital correlator to obtain a set of sequences such as "11110000111100001111111100000000". The digital correlator then identifies and matches the wake-up code and the code book. From the simulation results, it can be seen that the wake-up delay is 160ms and the wake-up code duration is 25ms.

[0085] Figure 4 The S11 parameter of the impedance matching network is exemplarily shown when the RF signal is 434 MHz. Figure 5 The S11 parameter of the impedance matching network is shown as an example when the RF signal is 915MHz. The S11 parameter represents the reflection coefficient, which represents the ability of the circuit to obtain antenna energy. The smaller the S11 parameter, the smaller the loss of the circuit system and the more energy it can obtain. Figure 4 and Figure 5 The impedance matching network designed by the present invention can achieve matching frequencies of 434MHz and 915MHz respectively. Figure 4 It can be seen that the reflection coefficient of the impedance matching network at a frequency of 434MHz is -56dB, which meets the application requirement of S11 less than -15dB; and the reflection coefficient of the impedance matching network at a frequency of 915MHz is -19dB, which also meets the application requirement of S11 less than -15dB. In this case, the circuit system can achieve time-division multiplexing matching.

[0086] Figure 6 The transient voltage simulation results of the impedance matching network when the RF signal is 434 MHz are shown as examples. Figure 7 The transient voltage simulation results of the impedance matching network when the RF signal is 915MHz are shown as an example. Figure 6 It can be seen that when obtaining a 434MHz RF signal for wake-up reception, the RF signal power given to the RF input is -60dBm (the input signal amplitude is 0.18mV), and the designed blocking-conduction switch can provide a passive voltage gain of about 12.4dB. Figure 7 The blocking-conduction switch obtains the 915MHz RF signal. When the input signal power is -35dBm (i.e. the input signal amplitude is 7.5mV), Figure 7It can be seen that when energy is harvested based on a 915MHz RF signal, the designed time-division multiplexing matching system can provide a passive voltage gain of 21.6dB (calculated based on the voltage gain conversion method in the RF field).

[0087] In summary, the time-sharing multiplexing matching system for RF energy collection and wake-up receiver provided by the embodiment of the present invention adopts tunable RF switch technology to adjust the impedance of the path so that the impedance cannot meet the impedance matching requirements, thereby blocking the matching network from passively amplifying the RF signal on this path, indirectly achieving signal blocking and conduction, avoiding the use of RF switch, solving the problem that the RF signal cannot be shut down, and realizing time-sharing multiplexing of RF energy collection and wake-up receiver WuRX unit, thereby improving the energy efficiency and integration of the RF self-powered wake-up receiver; the impedance matching network adopts a π-type matching network structure design, which simplifies the complexity of the impedance matching network, passively amplifies the RF signal, and ensures good frequency selection filtering performance; by adjusting the gate voltage and capacitance value of the transistor in the blocking-conduction switch, impedance matching of signals in different frequency bands can be achieved, thereby improving the flexibility and application range of the RF self-powered wake-up receiver; since the RF self-powered wake-up receiver can realize time-sharing reception of RF signals of two different frequencies, the energy efficiency and reliability of the RF self-powered wake-up receiver are further improved.

[0088] In the description of this specification, the reference terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0089] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the above-mentioned disclosed embodiments by viewing the drawings and the disclosed content. In the description of the present invention, the word "comprising" does not exclude other components or steps, "one" or "an" does not exclude multiple situations, and the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0090] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A time-division multiplexing matching system for radio frequency energy harvesting and receiver wake-up, characterized in that: include: The antenna is used to receive radio frequency signals; An impedance matching network is connected to the antenna and is used to perform impedance matching on the received radio frequency signal so that the impedance of the time-division multiplexing matching system is equal to the impedance of the antenna; The blocking-conducting switch is connected to the output end of the impedance matching network and is used as a switching element to adjust the impedance of the RF-DC unit and the wake-up receiver WuRX unit according to the internal enable signal to obtain a radio frequency adjustment signal; The RF-DC unit is connected to the blocking-conducting switch and is used to convert the RF adjustment signal into DC power to power the wake-up receiver WuRX unit; The wake-up receiver WuRX unit is connected to the blocking-conduction switch and is configured to be awakened when receiving a radio frequency adjustment signal of a preset frequency; The blocking-conducting switch performs impedance adjustment based on tunable radio frequency switch technology to achieve time-division multiplexing of radio frequency energy collection and awakening of the awakening receiver WuRX unit; The blocking-conducting switch includes: a PMOS transistor M1, a PMOS transistor M2, an adjustable capacitor C IN_W and adjustable capacitor C IN_R ; The blocking-conducting switch controls the impedance of the RF-DC unit and the wake-up receiver WuRX unit respectively by adjusting the gate voltages of the PMOS transistor M1 and the PMOS transistor M2.

2. The time-division multiplexing matching system for radio frequency energy harvesting and receiver wake-up according to claim 1, characterized in that: The source of the PMOS transistor M1 is connected to the RF-DC unit and the adjustable capacitor C IN_R The upper plate connection; The source of the PMOS transistor M2 is connected to the wake-up receiver WuRX unit and the adjustable capacitor C IN_W The lower plate connection; The adjustable capacitor C IN_R The lower plate and the adjustable capacitor C IN_W The upper plates are connected to each other and grounded; The drain of the PMOS transistor M1, the drain of the PMOS transistor M2 and the output end of the impedance matching network are connected to each other; The gate of the PMOS transistor M1 is connected to the internal enable signal EN_RFDC; the gate of the PMOS transistor M2 is connected to the internal enable signal EN_WuRX; The internal enable signal EN_RFDC and the internal enable signal EN_WuRX are both outputted by a control module in the wake-up receiver WuRX unit.

3. The time-division multiplexing matching system for radio frequency energy harvesting and receiver wake-up according to claim 1, characterized in that: The impedance matching network is a π-type matching network; The π-type matching network includes: capacitor C1, capacitor C2 and inductor L1; One end of the inductor L1 is connected to the antenna and the upper plate of the capacitor C1 respectively; the other end of the inductor L1 is connected to the output end of the π-type matching network and the upper plate of the capacitor C2 respectively; The lower plate of the capacitor C1 and the lower plate of the capacitor C2 are connected to each other and grounded.

4. The time-division multiplexing matching system for radio frequency energy harvesting and receiver wake-up according to claim 2, characterized in that: During the RF energy collection phase of the RF-DC unit, the internal enable signal EN_WuRX is high, the internal enable signal EN_RFDC is low, and the adjustable capacitor C IN_W and adjustable capacitor C IN_R is at a first preset value, so that the on-resistance of the PMOS transistor M2 is greater than that of the PMOS transistor M1, and the RF adjustment signal flows to the RF-DC unit; In the wake-up phase of the receiver WuRX unit, the internal enable signal EN_WuRX is low, the internal enable signal EN_RFDC is high, and the adjustable capacitor C IN_W and adjustable capacitor C IN_R Both are at a second preset value, so that the on-resistance of the PMOS transistor M2 is smaller than that of the PMOS transistor M1, and the RF adjustment signal flows to the wake-up receiver WuRX unit.

5. The time-division multiplexing matching system for radio frequency energy harvesting and receiver wake-up according to claim 1, characterized in that: The time-division multiplexing matching system for collecting radio frequency energy and waking up the receiver also includes: an energy storage capacitor C S and low dropout signal regulator LDO; The RF-DC unit is connected to the energy storage capacitor C S The low voltage difference signal regulator LDO provides a stable DC voltage for the wake-up receiver WuRX unit.

6. The time-division multiplexing matching system for radio frequency energy harvesting and receiver wake-up according to claim 2, characterized in that: The blocking-conducting switch is specifically configured by adjusting the width-to-length ratio of the PMOS transistor M1 and the PMOS transistor M2, the value of the internal enable signal EN_RFDC, the value of the internal enable signal EN_WuRX, the adjustable capacitor C IN_W and adjustable capacitor C IN_R The capacitance value is set to achieve impedance adjustment.

Images