Highly sensitive sensor system based on the principle of pt symmetry and detection method thereof

Abstract

This invention discloses a high-sensitivity sensor system and its detection method based on the PT symmetry principle. The circuit system consists of two main modules: a loss-sensitive end module composed of an inductor-capacitor-positive resistor connected in parallel, and a gain-readout end module composed of an inductor-capacitor-nonlinear negative resistor connected in parallel. The component parameters of the gain end and loss end meet the requirements of a PT symmetric electronic system. Signal transmission is achieved through inductive coupling between the two ends. By controlling the distance between the inductor coils, the system operates in a weak coupling region. In the initial state, the gain end and loss end are in a PT symmetric state. When the sensitive capacitance of the loss end / sensitive end changes slightly due to the influence of the measured parameter, the voltage of the gain end rises significantly, while the system resonant frequency remains unchanged. This system has the advantages of high sensitivity and wireless passive detection under weak coupling conditions.

Description

Technical Field

[0001] This invention belongs to the technical field of LC wireless passive sensing systems, specifically relating to a high-sensitivity sensor system based on the PT symmetry principle and its detection method. Background Technology

[0002] LC wireless passive sensors typically consist of an inductor and a sensitive capacitor. Their resonant frequency is usually modulated by the parameter being measured, and wireless passive detection is achieved through near-field coupling via external impedance analysis. LC wireless passive sensors have become a research hotspot in the field of IoT sensing due to their advantages such as wireless connectivity, remote interrogation capability, simple structure, and low power consumption. However, the magnetic field dissipation and weak coupling in small-sized LC wireless passive sensors greatly limit the sensor's sensitivity and wireless sensing distance. With the development of PT-symmetric quantum mechanics in optics, acoustics, and other fields, PT-symmetric electronics have also made significant progress in recent years. LC wireless passive sensors based on the PT-symmetry principle can achieve high-sensitivity detection and multi-parameter sensitivity. However, achieving high-sensitivity detection through PT symmetry inevitably introduces noise, and excessive noise may mask the improvement in sensitivity, which greatly limits the sensor's accuracy. Therefore, it is essential to invent a high-sensitivity wireless passive sensor detection system based on the PT-symmetry principle. Summary of the Invention

[0003] The purpose of this invention is to solve the problems mentioned in the background art and to provide a high-sensitivity sensor system and its detection method based on the PT symmetry principle;

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-sensitivity sensor system based on the PT symmetry principle, comprising: a gain-end resonant circuit and a loss-end resonant circuit, wherein the gain-end resonant circuit and the loss-end resonant circuit are coupled through mutual inductance, and the coupling coefficient between the gain-end resonant circuit and the loss-end resonant circuit is changed by changing the coupling distance between the gain-end resonant circuit and the loss-end resonant circuit, so as to ensure that the sensor system operates in a weakly coupled state.

[0005] Furthermore, the gain-end resonant circuit includes: a first inductor, a first capacitor, and a nonlinear negative resistor, wherein the first inductor and the nonlinear negative resistor are both connected in parallel across the first capacitor, and one end of the first capacitor is connected to ground.

[0006] Furthermore, the loss-end resonant circuit includes: a second inductor, a second capacitor, and a positive resistor. The second inductor and the positive resistor are connected in parallel across the two ends of the second capacitor. One end of the second capacitor is connected to ground. The second inductor and the first inductor are coupled to each other.

[0007] Furthermore, in the initial state of the sensor system, the inductance values ​​of the first inductor and the second inductor are equal, and the first capacitance and the second capacitance are equal.

[0008] Furthermore, in the initial state of the sensor system, the absolute value of the nonlinear negative resistance is less than the resistance value of the positive resistance.

[0009] The present invention also provides a detection method for the sensor system as described in any one of claims 1-6, comprising the following steps:

[0010] Step 1: Adjust the resistance value of the nonlinear negative resistor so that the absolute value of its equivalent negative resistance is less than the resistance value of the positive resistor in the resonant circuit at the loss end. At this time, the detection system is in an automatic PT symmetrical state and can start oscillating. Then adjust the coupling distance between the first inductor at the gain end and the second inductor at the loss end so that the system works in a weak coupling state and ensures that the coupling coefficient is greater than the gain loss coefficient.

[0011] Step 2: Measure the voltage of the resonant circuit at the gain end at this time and use it as the reference voltage, denoted as V1;

[0012] Step 3: Adjust the second capacitor by the slight change in the parameter to be measured, and measure the amplitude V1' of the oscillation voltage of the resonant circuit at the gain end at this time, so as to achieve high-sensitivity detection within the range of 10% of the parameter to be measured.

[0013] Beneficial effects:

[0014] 1. This invention changes the coupling coefficient between the gain-end resonant circuit and the loss-end resonant circuit by adjusting the coupling distance between them, thus placing the sensor system in a weakly coupled state and reducing the impact of noise on the sensor system. In the initial state of the sensor system, the gain-end resonant circuit and the loss-end resonant circuit are in a PT symmetrical state. At the same time, by adjusting the second capacitor through slight changes in the measured parameter, the voltage of the gain-end resonant circuit increases significantly, thereby amplifying the measured signal.

[0015] 2. The detection method described in this invention can achieve high-sensitivity wireless passive detection with a variation range of less than 10% for the parameter to be measured under weak coupling conditions based on the PT symmetry principle. Attached Figure Description

[0016] Figure 1 This is an equivalent circuit diagram of a high-sensitivity sensor system based on the PT symmetry principle of the present invention.

[0017] The markings in the diagram are as follows: 1. Gain-side resonant circuit; 2. Loss-side resonant circuit; 11. First inductor; 12. First capacitor; 13. Nonlinear negative resistor; 131. First resistor; 132. Second resistor; 133. Third resistor; 134. Operational amplifier; 21. Second inductor; 22. Second capacitor; 23. Positive resistor. Detailed Implementation

[0018] The invention will now be further explained with reference to the accompanying drawings.

[0019] like Figure 1 As shown, this invention provides a high-sensitivity sensor system based on the PT symmetry principle. It is characterized by comprising: a gain-end resonant circuit 1 and a loss-end resonant circuit 2, which are coupled together. The coupling coefficient between the gain-end resonant circuit 1 and the loss-end resonant circuit 2 is changed by altering the coupling distance between them, ensuring the sensor system operates in a weakly coupled state. In quantum mechanics, PT refers to parity-time reversal, and a system satisfying PT symmetry corresponds to an observable physical quantity. Specifically, changing the coupling distance between the gain-end resonant circuit 1 and the loss-end resonant circuit 2 is achieved by adjusting the coupling distance between the first inductor 11 and the second inductor 21.

[0020] The gain-end resonant circuit 1 includes: a first inductor 11, a first capacitor 12 and a nonlinear negative resistor 13. The first inductor 11 and the nonlinear negative resistor 13 are both connected in parallel across the first capacitor 12, and one end of the first capacitor 12 is connected to ground.

[0021] The nonlinear negative resistor 13 includes: a first resistor 131, a second resistor 132, a third resistor 133, and an operational amplifier 134. One end of the first resistor 131 is connected to the non-inverting input terminal of the operational amplifier 134, and the other end of the first resistor 131 is connected to the output terminal of the operational amplifier 134. One end of the second resistor 132 is connected to the output terminal of the operational amplifier 134, and the other end of the second resistor 132 is connected to the inverting input terminal of the operational amplifier 134. One end of the third resistor 133 is connected to the inverting input terminal of the operational amplifier 134, and the other end of the third resistor 133 is connected to ground.

[0022] The resonant circuit 2 at the loss end includes: a second inductor 21, a second capacitor 22 and a positive resistor 23. The second inductor 21 and the positive resistor 23 are connected in parallel across the two ends of the second capacitor 22. One end of the second capacitor 22 is connected to ground. The second inductor 21 is coupled to the first inductor 11.

[0023] In the above sensor system, the gain-end resonant circuit 1 and the loss-end resonant circuit 2 achieve signal transmission through the mutual inductive coupling between the first inductor 11 and the second inductor 21.

[0024] In the initial state of the sensor system, the inductance values ​​of the first inductor 11 and the second inductor 21 are equal, and the inductance values ​​of the first capacitor 12 and the second capacitor 22 are equal.

[0025] The specific working process of the sensor system is as follows:

[0026] First, adjust the nonlinear negative resistance R G The absolute value is slightly smaller than the positive resistance R of the loss resonant circuit 2. L The resistance value allows the system to be in an automatic PT symmetrical state and to start oscillation. The nonlinear linear negative resistance satisfies the formula: R1, R2, and R3 are the resistance values ​​of the first resistor 131, the second resistor 132, and the third resistor 133, respectively.

[0027] Next, the coupling distance between the first inductor 11 at the gain end and the second inductor 21 at the loss end is adjusted to make the system operate in a weakly coupled state while ensuring the coupling coefficient. Slightly larger than the gain loss factor Where d 12 This refers to the coupling distance, where r1 is the coil radius of the first inductor 11, r2 is the coil radius of the second inductor 21, and L... L It is the inductance value of the second inductor 21, C. L This is the capacitance value of the second capacitor, 22, R. L It is the resistance value of positive resistor 23.

[0028] Then measure the voltage of the resonant circuit (1) at the gain end at this time as the reference voltage V1.

[0029] Finally, by adjusting the second capacitor (22) through the slight change of the parameter to be measured, the amplitude of the oscillation voltage V1' at the gain terminal (1) is recorded. The value of V1'-V1 can reflect the change of the parameter to be measured, thereby achieving high-sensitivity detection within the range of 10% of the change of the parameter to be measured.

[0030] The present invention also provides a detection method for the sensor system as described in any one of claims 1-6, comprising the following steps:

[0031] Step 1: Adjust the resistance value of the nonlinear negative resistor 13 so that the absolute value of its equivalent negative resistance is less than the resistance value of the positive resistor 23 in the resonant circuit 2 at the loss end. At this time, the detection system is in an automatic PT symmetrical state and can start oscillating. Then adjust the coupling distance between the first inductor 11 at the gain end and the second inductor 21 at the loss end so that the system works in a weak coupling state and ensures that the coupling coefficient is greater than the gain loss coefficient.

[0032] Step 2: Measure the voltage of the resonant circuit 1 at the gain end at this time and use it as the reference voltage, denoted as V1;

[0033] Step 3: Adjust the second capacitor 22 by the slight change of the parameter to be measured, and measure the amplitude of the oscillation voltage V1' of the resonant circuit 1 at the gain end at this time. The value of V1'-V1 can reflect the change of the parameter to be measured, thereby achieving high-sensitivity detection within the range of 10% of the change of the parameter to be measured.

[0034] In summary, this invention changes the coupling coefficient between the gain-end resonant circuit and the loss-end resonant circuit by adjusting the coupling distance between them, thus placing the sensor system in a weakly coupled state and reducing the impact of noise on the sensor system. Furthermore, in the initial state of the sensor system, the gain-end resonant circuit and the loss-end resonant circuit are in a PT-symmetrical state. Simultaneously, by adjusting the second capacitor through slight changes in the measured parameter, the voltage of the gain-end resonant circuit increases significantly, thereby amplifying the measured signal.

[0035] The present invention also enables high-sensitivity wireless passive detection of the measured parameter within a range of 10% under weak coupling conditions based on the PT symmetry principle through the aforementioned detection method.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A detection method for a high-sensitivity sensor system based on the PT symmetry principle, characterized in that, The sensor system includes a gain-end resonant circuit (1) and a loss-end resonant circuit (2). The gain-end resonant circuit (1) and the loss-end resonant circuit (2) are coupled through mutual inductance. The coupling coefficient between the gain-end resonant circuit (1) and the loss-end resonant circuit (2) is changed by changing the coupling distance between them, so as to ensure that the sensor system works in a weakly coupled state. The detection method includes the following steps: Step 1: Adjust the resistance value of the nonlinear negative resistor (13) so that the absolute value of its equivalent negative resistance is less than the resistance value of the positive resistor (23) in the resonant circuit (2) at the loss end. At this time, the detection system is in an automatic PT symmetrical state and can start oscillating. Then adjust the coupling distance between the first inductor (11) at the gain end and the second inductor (21) at the loss end so that the system works in a weak coupling state and ensures that the coupling coefficient is greater than the gain loss coefficient. Step 2: Measure the voltage of the resonant circuit (1) at the gain end at this time as the reference voltage, denoted as . ; Step 3: Adjust the second capacitor (22) by the slight change in the parameter to be measured, and measure the oscillation voltage amplitude of the resonant circuit (1) at the gain end at this time. This allows for high-sensitivity detection within a 10% variation range of the parameter to be measured.

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