Parity-time symmetric passive sensing system, sensing measurement method and sensor

Abstract

The present invention discloses a parity-time symmetric passive sensing system, a sensing measurement method and a sensor, and relates to the field of sensor technology. The sensing system includes a gain loop, a loss loop, a neutral loop and a control module. The gain loop includes a vector network analysis module, a first negative resistor, a first inductor and a first capacitor; the loss loop includes a second resistor, a second capacitor and a second inductor; the neutral loop includes a third capacitor and a third inductor, and the neutral loop is arranged between the gain loop and the loss loop; the control module is connected to the gain loop and the neutral loop respectively, and is used to obtain the intrinsic frequency characteristic value of the sensing system through the vector network analysis module and adjust the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor to make the intrinsic frequency characteristic value higher than the intrinsic frequency threshold; the intrinsic frequency threshold is higher than the resonant frequency of the gain circuit. The present invention greatly improves the sensitivity of the sensing system.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a parity-time symmetric passive sensing system, a sensing measurement method and a sensor. Background Art

[0002] In the Hermitian system, the environment where the sensor is located may have energy loss and signal attenuation, resulting in low signal strength received by the sensor, which will reduce the sensitivity of the sensor. At the same time, the Hermitian system sensor may be interfered by external noise, such as electromagnetic interference, thermal noise, etc. These interferences will reduce the sensor's ability to detect the target signal. In the standard second-order EP (Exceptional Point) sensor in the non-Hermitian system, due to the generation of a splitting effect, the sensitivity of the system can be improved to a certain extent, but the degree of splitting is limited. If you want to get a divergent splitting effect, you need a nearly perfect inductive coupling, which in reality requires a high permeability magnetic core and a shielding plate. There are also many external factors such as material limitations and eddy current losses that will significantly reduce the coupling coefficient. Therefore, in the standard second-order system, it is almost impossible to get a divergent splitting, which also means that the standard second-order EP sensor cannot meet the requirements of some ultra-sensitive sensors.

[0003] In summary, a new type of sensor is urgently needed to solve the problem that existing sensors cannot achieve ultra-sensitive sensing. Summary of the invention

[0004] The main purpose of the present invention is to propose a parity-time symmetric passive sensing system, a sensing measurement method and a sensor, aiming to solve the problem that existing sensors cannot achieve ultra-sensitive sensing.

[0005] To achieve the above object, the present invention proposes a parity-time symmetric passive sensing system, comprising:

[0006] A gain loop, comprising a vector network analysis module, a first negative resistor, a first inductor coil and a first capacitor connected in series in sequence;

[0007] A loss loop, comprising a second resistor, a second capacitor and a second inductor connected in series in sequence;

[0008] A neutral loop, comprising a third capacitor and a third inductor connected in series in sequence, wherein the neutral loop is arranged between the gain loop and the loss loop;

[0009] A control module, which is respectively connected to the gain loop and the neutral loop, and is used to obtain the eigenfrequency characteristic value of the sensor system through the vector network analysis module, and adjust the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor to make the eigenfrequency characteristic value higher than the eigenfrequency threshold of the sensor system; the eigenfrequency threshold is higher than the resonant frequency of the gain circuit.

[0010] In one embodiment, the eigenfrequency characteristic value is the real part of the maximum eigenfrequency of the sensor system;

[0011] The resistance value of the first negative resistor and the resistance value of the second resistor are reciprocal numbers of each other; the capacitance values ​​of the first capacitor, the second capacitor and the third capacitor are the same; and the inductance values ​​of the first inductor coil, the second inductor coil and the third inductor coil are all the same.

[0012] In one embodiment, the quality factor γ of the sensor system satisfies the formula: L is the inductance of the first inductor, C is the capacitance of the first capacitor, R is the resistance of the second resistor, and R>0;

[0013] A first coupling coefficient μ between the gain loop and the neutral loop is the same as a second coupling coefficient between the loss loop and the neutral loop, and is different from a third coupling coefficient between the gain loop and the loss loop;

[0014] The first coupling coefficient μ and the third coupling coefficient κ conform to the formula:

[0015] The quality factor γ and the third coupling coefficient κ conform to the formula:

[0016] In one embodiment, the sensitivity of the sensing system is positively correlated with the first coupling coefficient.

[0017] In one embodiment, when the eigenfrequency characteristic value of the sensor system is higher than the eigenfrequency threshold and the quality factor of the sensor system is constant, the positional relationship between the gain loop and the loss loop corresponds one-to-one to the second eigenfrequency characteristic value of the sensor system.

[0018] In one embodiment, the resistance value of the first negative resistor is adjustable and when the positions of the gain loop and the loss loop remain constant, the inductance value of the second inductor remains constant, and the eigenfrequency characteristic value of the sensor system is lower than the eigenfrequency threshold, the inverse of the adjusted resistance value of the first negative resistor is the resistance measurement value of the second resistor; or,

[0019] The capacitance values ​​of the first capacitor and the third capacitor are adjustable and when the positions of the gain loop and the loss loop remain constant, the inductance value of the second inductor coil remains constant, and the eigenfrequency characteristic value of the sensing system is lower than the eigenfrequency threshold, the adjusted capacitance value of the first capacitor and / or the third capacitor is the capacitance measurement value of the second capacitor.

[0020] In one embodiment, the parameter value of the second resistor or the second capacitor may change with changes in environmental parameters;

[0021] The environmental parameter is one of environmental temperature, environmental humidity, and environmental magnetic field.

[0022] In one embodiment, the first negative resistor includes an operational amplifier circuit having a negative feedback circuit; within a frequency range of 10 to 50 MHz, an error in the negative resistance value of the first negative resistor is less than 10%.

[0023] The present invention further proposes a sensing measurement method, which is applied to the above-mentioned parity-time symmetric passive sensing system, and the sensing measurement method comprises:

[0024] Acquire a first eigenfrequency characteristic value of the sensor system through a vector network analysis module; the first eigenfrequency characteristic value is higher than an eigenfrequency threshold;

[0025] Placing the sensor system in a measurement environment to obtain a second eigenfrequency characteristic value of the sensor system;

[0026] When the second eigenfrequency characteristic value changes and is higher than the eigenfrequency threshold, determining the position change of the measurement environment according to the corresponding relationship between the eigenfrequency characteristic value and the position;

[0027] When the second eigenfrequency characteristic value changes and is lower than the eigenfrequency threshold, adjust the parameters of at least one of the first negative resistor, the first capacitor, and / or the third capacitor to restore the second eigenfrequency characteristic value to the first eigenfrequency characteristic value, and determine the change of the measurement environment based on the adjusted parameters.

[0028] The present invention also provides a sensor, comprising the above-mentioned parity-time symmetric passive sensing system.

[0029] In the technical solution of the present invention, a parity-time symmetric passive sensing system is adopted, which includes a gain loop, a loss loop, a neutral loop and a control module; the gain loop includes a vector network analysis module, a first negative resistor, a first inductor and a first capacitor connected in series in sequence; the loss loop includes a second resistor, a second capacitor and a second inductor connected in series in sequence; the neutral loop includes a third capacitor and a third inductor connected in series in sequence, and the neutral loop is arranged between the gain loop and the loss loop; the control module is respectively connected to the gain loop and the neutral loop, and is used to obtain the intrinsic frequency characteristic value of the sensing system through the vector network analysis module, and by adjusting the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor, the intrinsic frequency characteristic value is higher than the intrinsic frequency threshold of the sensing system; the intrinsic frequency threshold is higher than the resonant frequency of the gain circuit.

[0030] The sensing system obtains the eigenfrequency characteristic value of the sensing system through the vector network analysis module, and adjusts the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor to make the eigenfrequency characteristic value higher than the eigenfrequency threshold of the sensing system, and the eigenfrequency threshold is higher than the resonant frequency of the gain circuit. When the eigenfrequency characteristic value of the parity-time symmetric passive sensing system is higher than the eigenfrequency threshold of the sensing system, since the sensing system has eigenfrequency splitting, the eigenfrequency characteristic value can be further increased by adjusting the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor, and the increase in the eigenfrequency characteristic value reflects that the degree of splitting of the eigenfrequency is enhanced, thereby achieving the improvement of the sensitivity of the sensing system.

[0031] In addition, since there is a non-negligible noise problem in the existing singular point sensing system, the noise directly affects the accuracy of the sensing system readings. Therefore, in the first embodiment, the eigenfrequency characteristic value is higher than the eigenfrequency threshold of the sensing system; and the eigenfrequency threshold is higher than the resonant frequency of the gain circuit.

[0032] In this way, the eigenfrequency characteristic value as the working point of the sensor system can be kept away from the divergent singular point. In the sensor system, the working point close to the divergent singular point is sensitive to both small perturbations and noise, while the working point of the sensor system far away from the DEP is insensitive to both. Therefore, in this embodiment, by setting the working point of the sensor system, that is, the eigenfrequency characteristic value, to be higher than the eigenfrequency threshold of the sensor system, and the eigenfrequency threshold is higher than the resonant frequency of the gain circuit, so that the eigenfrequency characteristic value is kept away from the divergent singular point, the effect of effectively suppressing the excess noise from the collapse of the eigenbase and the amplification of the equipment noise is achieved, and the influence of environmental noise can be avoided, the influence of noise can be effectively avoided, and the ability to suppress noise is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0034] Figure 1 A schematic diagram of the circuit structure of an embodiment of a parity-time symmetric passive sensing system provided by the present invention;

[0035] Figure 2 A density diagram of the variation of the eigenfrequency ω3 with μ and κ when μ and κ are given for an embodiment of the parity-time symmetric passive sensing system provided by the present invention;

[0036] Figure 3 A graph showing the variation of the eigenfrequency ω3 with γ when μ and κ are given for one embodiment of the parity-time symmetric passive sensing system provided by the present invention;

[0037] Figure 4 A schematic diagram of the sensitivity of a displacement sensor constructed in an embodiment of a parity-time symmetric passive sensing system provided by the present invention;

[0038] Figure 5 A design circuit diagram of a negative resistor of an embodiment of a parity-time symmetric passive sensing system provided by the present invention;

[0039] Figure 6 A schematic diagram of the measured value of negative resistance of an embodiment of the parity-time symmetric passive sensing system provided by the present invention;

[0040] Figure 7 This is a design board diagram of the overall circuit of an embodiment of the parity-time symmetric passive sensing system provided by the present invention.

[0041] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0044] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] In the Hermitian system, the environment where the sensor is located may have energy loss and signal attenuation, resulting in low signal strength received by the sensor, which will reduce the sensitivity of the sensor. At the same time, the Hermitian system sensor may be interfered by external noise, such as electromagnetic interference, thermal noise, etc. These interferences will reduce the sensor's ability to detect the target signal. In the standard second-order EP (Exceptional Point) sensor in the non-Hermitian system, due to the generation of a splitting effect, the sensitivity of the system can be improved to a certain extent, but the degree of splitting is limited. If you want to get a divergent splitting effect, you need a nearly perfect inductive coupling, which in reality requires a high permeability magnetic core and a shielding plate. There are also many external factors such as material limitations and eddy current losses that will significantly reduce the coupling coefficient. Therefore, in the standard second-order system, it is almost impossible to get a divergent splitting, which also means that the standard second-order EP sensor cannot meet the requirements of some ultra-sensitive sensors.

[0046] In summary, a new type of sensor is urgently needed to solve the problem that existing sensors cannot achieve ultra-sensitive sensing.

[0047] The invention provides a parity-time symmetric passive sensing system.

[0048] See also Figure 1 In the first embodiment of the present invention, the parity-time symmetric passive sensing system comprises:

[0049] A gain loop, comprising a vector network analysis module, a first negative resistor, a first inductor coil and a first capacitor connected in series in sequence;

[0050] A loss loop, comprising a second resistor, a second capacitor and a second inductor connected in series in sequence;

[0051] A neutral loop, comprising a third capacitor and a third inductor connected in series in sequence, wherein the neutral loop is arranged between the gain loop and the loss loop;

[0052] A control module, which is respectively connected to the gain loop and the neutral loop, is used to obtain the eigenfrequency characteristic value of the sensor system through the vector network analysis module, and adjust the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor to make the eigenfrequency characteristic value higher than the eigenfrequency threshold of the sensor system; the eigenfrequency threshold is higher than the resonant frequency of the gain circuit.

[0053] In this embodiment, the circuit diagram of the sensor system is as follows: Figure 1 As shown, the parity-time symmetric passive sensing system includes a gain circuit (a resonant circuit composed of R, Z0, L, and C in the figure, i.e., an RLC resonator and a vector network analysis module), a neutral circuit (LC resonator), and a loss circuit (RLC resonator). The three circuits interact with each other through the inductive coupling effect to form the parity-time symmetric passive sensing system.

[0054] The sensing system obtains the eigenfrequency characteristic value of the sensing system through the vector network analysis module, and adjusts the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor to make the eigenfrequency characteristic value higher than the eigenfrequency threshold of the sensing system, and the eigenfrequency threshold is higher than the resonant frequency of the gain circuit. When the eigenfrequency characteristic value of the parity-time symmetric passive sensing system is higher than the eigenfrequency threshold of the sensing system, since the sensing system has eigenfrequency splitting, the eigenfrequency characteristic value can be further increased by adjusting the parameters of at least one of the first negative resistor, the first capacitor and / or the third capacitor, and the increase in the eigenfrequency characteristic value reflects that the degree of splitting of the eigenfrequency is enhanced, thereby achieving the improvement of the sensitivity of the sensing system.

[0055] In addition, since there is a non-negligible noise problem in the existing singular point sensing system, the noise directly affects the accuracy of the sensing system readings. Therefore, in the first embodiment, the eigenfrequency characteristic value is higher than the eigenfrequency threshold of the sensing system; the eigenfrequency threshold is higher than the resonant frequency of the gain circuit.

[0056] In this way, the eigenfrequency characteristic value as the working point of the sensor system can be kept away from the divergent singular point. In the sensor system, the working point close to the divergent singular point is sensitive to both small perturbations and noise, while the working point of the sensor system far away from the DEP is insensitive to both. Therefore, in this embodiment, by setting the working point of the sensor system, that is, the eigenfrequency characteristic value, to be higher than the eigenfrequency threshold of the sensor system, and the eigenfrequency threshold is higher than the resonant frequency of the gain circuit, so that the eigenfrequency characteristic value is kept away from the divergent singular point, the effect of effectively suppressing the excess noise from the collapse of the eigenbase and the amplification of the equipment noise is achieved, and the influence of environmental noise can be avoided, the influence of noise can be effectively avoided, and the ability to suppress noise is improved.

[0057] Based on the first embodiment of the present invention, in a second embodiment of the present invention, the eigenfrequency characteristic value is the real part of the maximum eigenfrequency of the sensing system;

[0058] The resistance value of the first negative resistor is the inverse of the resistance value of the second resistor; the capacitance values ​​of the first capacitor, the second capacitor and the third capacitor are the same; the inductance values ​​of the first inductor coil, the second inductor coil and the third inductor coil are all the same.

[0059] In the second embodiment, it should be noted that the eigenfrequency of the sensing system is divided into two parts by the divergent singular point. One part is complex conjugate, and this phase is called the broken phase. Since the value of the imaginary part is meaningless in the actual system, if only the real part is considered, at this time, the entire sensing system has only one eigenfrequency value. In another phase, it is called the accurate phase. In the accurate phase, the eigenfrequency value is a pure real value. At this time, the eigenfrequency value of the sensing system is split from one to three. The eigenfrequency characteristic value in this embodiment is the real part of the maximum eigenfrequency of the sensing system, which refers to the largest eigenfrequency among the three eigenfrequency values ​​of the sensing system in the accurate phase.

[0060] In the second embodiment, since the ratio of ω1 to ω2 in the three eigenfrequency values ​​ω1, ω2, and ω3 of the sensing system in the exact phase is always close to the resonant frequency ω0 of the sensing system, it is difficult to increase the degree of splitting of the eigenfrequency by adjusting the values ​​of ω1 and ω2. Therefore, the present invention increases the value of ω3 (i.e., the eigenfrequency characteristic value) to achieve the maximum value, thereby enhancing the degree of splitting of the eigenfrequency and further improving the sensitivity of the sensing system.

[0061] In order to make the sensing system realize parity-time symmetry, the sensing system also needs to meet the prerequisite of parity-time symmetry: the resistance value of the first negative resistor and the resistance value of the second resistor are opposite to each other; the capacitance values ​​of the first capacitor, the second capacitor and the third capacitor are the same; the inductance values ​​of the first inductor, the second inductor and the third inductor are the same. In this way, by setting the above conditions, the sensing system meets the parity-time symmetry condition. It should be noted that, since the current is the first-order derivative of the electric quantity and time, in order to meet the time symmetry, the resistance value of the first negative resistor of the gain loop and the resistance value of the second resistor are set to be opposite to each other.

[0062] Furthermore, since the gain loop, loss loop, and neutral loop interact with each other through the inductive coupling effect, the inductive cross-coupling effect between the gain loop and the loss loop is inevitable. In the existing third-order parity-time symmetry sensing system, the cross-coupling effect is ignored, resulting in the third-order parity-time symmetry sensing system constructed on this basis cannot be extended to practical applications.

[0063] To solve the above problem, in a third embodiment of the present invention, the quality factor γ of the sensor system complies with the formula: L is the inductance of the first inductor, C is the capacitance of the first capacitor, R is the resistance of the second resistor, and R>0;

[0064] A first coupling coefficient μ between the gain loop and the neutral loop is the same as a second coupling coefficient between the loss loop and the neutral loop, and is different from a third coupling coefficient between the gain loop and the loss loop;

[0065] The first coupling coefficient μ and the third coupling coefficient κ conform to the formula:

[0066] The quality factor γ and the third coupling coefficient κ conform to the formula:

[0067] In the third embodiment, compared with the existing third-order parity-time symmetry sensing system which can only be applied to the special case of κ=0 and is difficult to put into practical application, the technical solution of the present invention obtains the analytical solution between μ and κ through experiments and calculations: It is possible to generalize κ to any value, which greatly expands the application scenarios of the third-order parity-time symmetry system and realizes the practical application of the divergent singular point sensing system based on third-order parity-time symmetry.

[0068] The present invention increases the eigenfrequency characteristic value to achieve the maximum value, thereby enhancing the degree of splitting of the eigenfrequency and thus improving the sensitivity of the sensing system. To maximize ω3, it is necessary to simultaneously satisfy In this condition, It means that by setting a larger γ value, the sensor system can have frequency splitting, so that the eigenfrequency eigenvalue exists. The researchers obtained a density map by observing the change of the eigenfrequency eigenvalue with μ and κ, and found the values ​​of μ and κ that maximize the eigenfrequency eigenvalue through the density map. And through calculation, the analytical solution between μ and κ at this time is obtained as When this condition is met, the system sensitivity is extremely high. DEP In order to construct the theoretical value obtained by setting the denominator of the eigenfrequency to 0 in the DEP process, the denominator cannot be equal to 0 in practice. Therefore, by setting μ to Within this range, the divergent splitting in the sensor system increases and brings the sensor system close to the maximum sensitivity point.

[0069] For details, see Figure 2 , for each different κ, there will be a corresponding μ, so that ω3 is maximized; generalizing it to practical applications, corresponding to different positional relationships between the gain loop and the loss loop, a suitable μ can be found to construct a divergent singular point (DEP). As an optional implementation, μ can be set to 0.99μ DEP ; See Figure 3 , when setting the same κ and different μ, there will be different splitting situations. When μ=0.99μ DEP In the case of , an obvious divergent split can be observed in the figure (yellow line in the figure).

[0070] Further, in the fourth embodiment of the present invention, the sensitivity of the sensing system is positively correlated with the first coupling coefficient.

[0071] Based on the third embodiment, it can be seen that μ is set to When the value is within , the divergent splitting in the sensor system increases, and the sensor system reaches the highest sensitivity point. According to the fourth embodiment, the sensitivity of the sensor system is positively correlated with the first coupling coefficient. Therefore, if the sensitivity of the sensor system is to reach the highest point, μ can be made as close as possible to This theoretical value greatly improves the sensitivity of the sensing system and achieves ultra-high sensitivity sensing effect.

[0072] In a fifth embodiment of the present invention, when the eigenfrequency characteristic value of the sensor system is higher than the eigenfrequency threshold and the quality factor of the sensor system remains constant, the positional relationship between the gain loop and the loss loop corresponds one-to-one to the second eigenfrequency characteristic value of the sensor system.

[0073] In this embodiment, based on the one-to-one correspondence between the positional relationship between the gain loop and the loss loop and the characteristic value of the second eigenfrequency of the sensing system, the sensing system can be used to manufacture a displacement sensor.

[0074] Specifically, the eigenfrequency characteristic value of the sensor system is in the splitting interval under the condition that the eigenfrequency characteristic value is higher than the eigenfrequency threshold value and the quality factor of the sensor system is constant, so that the sensor system is in a high-sensitivity state; by obtaining the change amount of the second eigenfrequency characteristic value, specifically, by obtaining the change amount of the first coupling coefficient μ, the change of the positional relationship between the gain loop and the loss loop is obtained. The change of the positional relationship between the gain loop and the loss loop corresponds to the displacement, so when the second eigenfrequency characteristic value is used as the measurement value, the sensor system is a displacement sensor system.

[0075] The displacement sensing system obtained by taking the technical solution of this embodiment as the sensing principle not only has the advantage of maintaining the above conditions during the measurement process, thereby ensuring that the intrinsic frequency characteristic value of the sensing system is within the splitting interval, making the sensing system in a high-sensitivity state, thereby achieving high-sensitivity measurement of the displacement.

[0076] In this embodiment, the coupling coefficient μ of the sensing system is used as the measurement value of the sensing end to construct an example of a displacement sensor. The sensitivity of the sensing system is as follows: Figure 3 As shown, first, γ and κ are set to be fixed, and γ = 5, κ = 0.1. At this time, different coupling coefficients μ correspond to different eigenfrequency values ​​ω3, and also correspond to different splitting situations. Figure 4 As shown, especially when in the interval of μ∈[0.70,0.74], the value of ω3 is greatly improved, showing the ultra-sensitive performance of the sensing system. Therefore, the displacement sensor made using this principle is ultra-high precision and has broad application prospects.

[0077] In a sixth embodiment of the present invention, the resistance value of the first negative resistor is adjustable and when the positions of the gain loop and the loss loop remain constant, the inductance value of the second inductor coil remains constant, and the eigenfrequency characteristic value of the sensing system is lower than the eigenfrequency threshold value, the inverse of the adjusted resistance value of the first negative resistor is the resistance measurement value of the second resistor; or,

[0078] The capacitance values ​​of the first capacitor and the third capacitor are adjustable and when the positions of the gain loop and the loss loop remain constant, the inductance value of the second inductor coil remains constant, and the eigenfrequency characteristic value of the sensing system is lower than the eigenfrequency threshold, the adjusted capacitance value of the first capacitor and / or the third capacitor is the capacitance measurement value of the second capacitor.

[0079] In this embodiment, two sensing principles are provided, namely, sensing for resistance and sensing for capacitance. In the resistance sensing principle, when the eigenfrequency characteristic value of the sensing system is lower than the eigenfrequency threshold, the resistance value of the first negative resistor is adjusted so that the adjusted eigenfrequency characteristic value is higher than the eigenfrequency threshold, thereby reappearing the divergent singular point. At this time, the opposite number of the resistance value of the first negative resistor is the resistance measurement value of the second resistor. In this way, the resistance measurement value of the second resistor can be obtained on the first negative resistor, thereby realizing sensing.

[0080] Similarly, in the sensing principle of capacitance, when the eigenfrequency characteristic value of the sensing system is lower than the eigenfrequency threshold, the capacitance value of the first capacitor and / or the third capacitor is adjusted so that the adjusted eigenfrequency characteristic value is higher than the eigenfrequency threshold, thereby reappearing the divergent singular point. At this time, the capacitance value corresponding to the adjusted capacitance is the capacitance measurement value of the second capacitor. In this way, the capacitance measurement value of the second capacitor can be obtained on the first capacitor and / or the third capacitor, thereby realizing sensing.

[0081] In the above process, after the divergent singular point of the sensor system reappears, the eigenfrequency characteristic value is higher than the eigenfrequency threshold, and the eigenfrequency threshold is higher than the resonant frequency of the gain circuit, that is, it is far away from the divergent singular point, so the sensor system has a strong ability to suppress noise interference; and due to the reconstruction of the divergent singular point, the sensor system has the maximum degree of splitting, so the sensor system has extremely high sensitivity. That is to say, in this embodiment, the sensor system can not only suppress noise interference in the process of realizing the measurement of capacitance or resistance, but also improve the sensitivity of the sensor system, and realize high-precision measurement of capacitance or resistance.

[0082] Furthermore, based on the sixth embodiment of the present invention, in the seventh embodiment of the present invention, the parameter value of the second resistor or the second capacitor may change with the change of the environmental parameter;

[0083] The environmental parameter is one of environmental temperature, environmental humidity, and environmental magnetic field.

[0084] Among them, it should be noted that, based on the sensing mechanism of the present sensing system, resistors such as varistors, thermistors, and hygrometers can be used as the second resistor in this embodiment, so as to realize high-precision measurement of parameters such as ambient pressure, ambient temperature, and ambient humidity using the present sensing system; or a movable capacitor plate can be used as the second capacitor in this embodiment, so as to realize high-precision measurement of ambient magnetic field parameters using the present sensing system.

[0085] Based on the first embodiment of the present invention, in an eighth embodiment of the present invention, the first negative resistor includes an operational amplifier circuit having a negative feedback circuit; within a frequency range of 10 to 50 MHz, an error in the negative resistance value of the first negative resistor is less than 10%.

[0086] Specifically, combined Figure 5 Each circuit in this embodiment is described, wherein: Figure 5 (a) is a negative resistance circuit diagram in the present sensing system, which actually uses an operational amplifier circuit with a negative feedback resistor to form a negative resistance; Figure 5 (b) is a decoupling circuit at the power supply end of the sensor system, which is used to maintain the stability of the circuit system; Figure 5 (c) is the overall equivalent circuit of the negative resistance circuit. Its overall equivalent circuit is a parallel connection of resistance and capacitance, that is, the real and imaginary parts of the input impedance are composed of R and C. The impedance diagram Z is measured by VNA. 11 , get the real and imaginary part of the input impedance, and then use MATLAB software to calculate the negative resistance of the designed circuit. The calculation results are as follows: Figure 6 As shown, in Figure 6 In the frequency range of 10MHz-50MHz, the value of negative impedance can be kept within 10% error, meeting the error requirement of the sensing system. Finally, the design board diagram of the overall circuit of the present invention is as follows: Figure 7 shown.

[0087] In an embodiment of the present invention, the sensing system is constructed as a sensor, and the sensor is a wireless passive sensing system.

[0088] Among them, wireless sensors are composed of many spatially distributed sensor nodes, which are interconnected through wireless signals and work together to complete various data collection tasks. Their core advantages are flexible deployment, relatively low cost, and the ability to work in environments that are difficult or impossible for humans to reach. Passive sensors are sensing devices that do not require internal power to operate. They are activated and operated by external energy. Their main advantages are durability and the ability to operate for a long time in an environment without the need for battery replacement, which greatly reduces maintenance costs and environmental impact. Therefore, in this embodiment, the solution of setting the sensor as a wireless passive sensor is adopted, so that the sensor has both flexible deployment and the ability to work for a long time in an environment without internal power supply.

[0089] In an embodiment of the present invention, the third-order parity-time symmetric system is a non-Hermitian system, and the energy of the non-Hermitian system includes real values ​​and complex values.

[0090] Among them, a non-Hermitian system means that when the Hamiltonian of the system is no longer a Hermitian operator, the system is considered a non-Hermitian system. Compared with the Hermitian system that uses the Hermitian operator as the Hamiltonian of the system, the non-Hermitian system can describe the dynamic behavior of an open system or an active system, such as a laser, a gain-loss structure in a photonic crystal, and a gain-loss in a sensor system. In addition, since a non-Hermitian system can have external dissipation or excitation, for an open system, the system exchanges energy with the external environment, so that the energy of the system no longer has to be a real number, but can even have a complex value, where the real part represents the energy and the imaginary part represents the attenuation or gain of the energy for a system with a complex value; and the introduction of complex energy values, especially when the system works near a singular point, can greatly enhance the response characteristics of the system, thereby improving the sensitivity of the sensor system.

[0091] The present invention further provides a sensing measurement method, which is applied to the parity-time symmetric passive sensing system of any of the above embodiments. The sensing measurement method comprises:

[0092] Obtaining a first eigenfrequency characteristic value of the sensor system through a vector network analysis module; the first eigenfrequency characteristic value is higher than an eigenfrequency threshold;

[0093] The sensor system is placed in a measurement environment to obtain a second eigenfrequency characteristic value of the sensor system;

[0094] When the second eigenfrequency characteristic value changes and is higher than the eigenfrequency threshold, the position change of the measurement environment is determined according to the corresponding relationship between the eigenfrequency characteristic value and the position;

[0095] When the second eigenfrequency characteristic value changes and is lower than the eigenfrequency threshold, adjust the parameters of at least one of the first negative resistor, the first capacitor, and / or the third capacitor to restore the second eigenfrequency characteristic value to the first eigenfrequency characteristic value, and determine the change of the measurement environment based on the adjusted parameters.

[0096] In this sensing measurement method, measurement is mainly achieved through two measurement methods: one is to measure the change of the second eigenfrequency characteristic value, and measure the position change of the environment according to the corresponding relationship between the eigenfrequency characteristic value and the position; this measurement method is used to measure the change of the environmental position, that is, the displacement parameter;

[0097] The second is to adjust the corresponding resistance or capacitance, specifically the parameters of at least one of the first negative resistance, the first capacitance, and / or the third capacitance, when the second intrinsic frequency characteristic value changes and is lower than the intrinsic frequency threshold, so that the second intrinsic frequency characteristic value is restored to the first intrinsic frequency characteristic value; in the process of restoring the second intrinsic frequency characteristic value to the first intrinsic frequency characteristic value, the reconstruction of the divergent singular point is completed, thereby achieving the high sensitivity reproduction of the sensing system and reducing the sensitivity of the sensing system to noise. The parameters of the resistance or capacitance after adjustment in this process correspond to the changes in the environment, thereby achieving the measurement of environmental changes such as ambient temperature, ambient humidity, and / or ambient magnetic field.

[0098] The present invention also proposes a sensor, which includes the above-mentioned parity-time symmetric passive sensing system. The specific structure of the parity-time symmetric passive sensing system refers to the above-mentioned embodiment. Since this sensor adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0099] The sensor may be a displacement sensor, a pressure sensor, a temperature sensor, a humidity sensor, or a magnetic field sensor.

[0100] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A parity-time symmetric passive sensing system, characterized in that: include: A gain loop, comprising a vector network analysis module, a first negative resistor, a first inductor coil and a first capacitor connected in series in sequence; A loss loop, comprising a second resistor, a second capacitor and a second inductor connected in series in sequence; A neutral loop, comprising a third capacitor and a third inductor connected in series in sequence, wherein the neutral loop is arranged between the gain loop and the loss loop; a control module, which is connected to the gain loop and the neutral loop respectively, and is used to obtain an eigenfrequency characteristic value of the sensor system through the vector network analysis module, and adjust a parameter of at least one of the first negative resistor, the first capacitor and / or the third capacitor so that the eigenfrequency characteristic value is higher than an eigenfrequency threshold of the sensor system; the eigenfrequency threshold is higher than the resonant frequency of the gain loop; The eigenfrequency characteristic value is the real part of the maximum eigenfrequency of the sensor system; The resistance value of the first negative resistor and the resistance value of the second resistor are reciprocal numbers of each other; the capacitance values ​​of the first capacitor, the second capacitor and the third capacitor are the same; and the inductance values ​​of the first inductor coil, the second inductor coil and the third inductor coil are all the same.

2. The sensor system according to claim 1, characterized in that The quality factor γ of the sensor system complies with the formula: L is the inductance of the first inductor, C is the capacitance of the first capacitor, R is the resistance of the second resistor, and R>0; A first coupling coefficient μ between the gain loop and the neutral loop is the same as a second coupling coefficient between the loss loop and the neutral loop, and is different from a third coupling coefficient between the gain loop and the loss loop; The first coupling coefficient μ and the third coupling coefficient κ conform to the formula: The quality factor γ and the third coupling coefficient κ conform to the formula:

3. The sensor system according to claim 2, characterized in that The sensitivity of the sensing system is positively correlated with the first coupling coefficient.

4. The sensor system according to claim 2, characterized in that When the eigenfrequency characteristic value of the sensor system is higher than the eigenfrequency threshold and the quality factor of the sensor system remains constant, the positional relationship between the gain loop and the loss loop corresponds one-to-one to the second eigenfrequency characteristic value of the sensor system.

5. The sensor system according to claim 2, characterized in that: When the resistance value of the first negative resistor is adjustable and the positions of the gain loop and the loss loop remain constant, the inductance value of the second inductor remains constant, and the eigenfrequency characteristic value of the sensor system is lower than the eigenfrequency threshold, the inverse of the adjusted resistance value of the first negative resistor is the resistance measurement value of the second resistor; or, The capacitance values ​​of the first capacitor and the third capacitor are adjustable and when the positions of the gain loop and the loss loop remain constant, the inductance value of the second inductor coil remains constant, and the eigenfrequency characteristic value of the sensing system is lower than the eigenfrequency threshold, the adjusted capacitance value of the first capacitor and / or the third capacitor is the capacitance measurement value of the second capacitor.

6. The sensor system according to claim 5, characterized in that The parameter value of the second resistor or the second capacitor may change with the change of environmental parameters; The environmental parameter is one of environmental temperature, environmental humidity, and environmental magnetic field.

7. The sensor system according to claim 1, characterized in that: The first negative resistor includes an operational amplifier circuit with a negative feedback circuit; within a frequency range of 10 to 50 MHz, the error of the negative resistance value of the first negative resistor is less than 10%.

8. A sensing measurement method, characterized in that: Applied to the parity-time symmetric passive sensing system according to any one of claims 1 to 7, the sensing measurement method comprises: Acquire a first eigenfrequency characteristic value of the sensor system through a vector network analysis module; the first eigenfrequency characteristic value is higher than an eigenfrequency threshold; Placing the sensor system in a measurement environment to obtain a second eigenfrequency characteristic value of the sensor system; When the second eigenfrequency characteristic value changes and is higher than the eigenfrequency threshold, determining the position change of the measurement environment according to the corresponding relationship between the eigenfrequency characteristic value and the position; When the second eigenfrequency characteristic value changes and is lower than the eigenfrequency threshold, adjust the parameters of at least one of the first negative resistor, the first capacitor, and / or the third capacitor to restore the second eigenfrequency characteristic value to the first eigenfrequency characteristic value, and determine the change of the measurement environment based on the adjusted parameters.

9. A sensor, characterized in that: The invention comprises the parity-time symmetric passive sensing system as claimed in any one of claims 1 to 7.

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