High-sensitivity sensor system based on principle of PT symmetry, and detection method therefor

Abstract

A high-sensitivity sensor system based on the principle of PT symmetry. The system comprises: a loss-end / sensitive-end module, which is formed by means of connecting an inductor, a capacitor and a positive resistor in parallel; and a gain-end / readout-end module, which is formed by means of connecting an inductor, a capacitor and a nonlinear negative resistor in parallel. Element parameters of a gain end and a loss end meet the requirements of a PT symmetric electronic system; signal transmission between the two ends is implemented by means of inductive coupling; the system operates in a weak coupling area by means of controlling the distance between inductor coils; and in an initial state, the gain end and the loss end are in a PT symmetric state. When the sensitive capacitance of the loss end / sensitive end changes due to the weak influence of a parameter to be measured, the voltage of the gain end is in a greatly rising state, and the resonant frequency of the system remains unchanged, such that high-sensitivity wireless passive detection under a weak coupling condition can be realized. Further disclosed is a detection method for a sensor system based on the principle of PT symmetry.

Description

Highly sensitive sensor system and detection method based on PT symmetry principle Technical Field

[0001] The present invention belongs to the technical field of LC wireless passive sensing systems, and in particular relates to a high-sensitivity sensor system based on the PT symmetry principle and a detection method thereof. Background Art

[0002] LC wireless passive sensors typically consist of an inductor and a sensitive capacitor. Their resonant frequency is typically modulated by the parameter to be 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, including wireless connectivity, remote interrogation, simple structure, and low power consumption. However, the magnetic field dissipation and weak coupling in small LC wireless passive sensors significantly limit their sensitivity and wireless sensing range. With the development of PT-symmetric quantum mechanics in fields such as optics and acoustics, PT-symmetric electronics has also achieved 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. Excessive noise can mask the increased sensitivity, significantly limiting sensor accuracy. Therefore, it is imperative to develop a high-sensitivity wireless passive sensor detection system based on the PT-symmetry principle.

[0003] Summary of the Invention

[0004] The purpose of the present invention is to solve the problems mentioned in the background technology and provide a highly sensitive sensor system and a detection method thereof based on the PT symmetry principle;

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a highly sensitive 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, thereby ensuring that the sensor system operates in a weakly coupled state.

[0007] Furthermore, the gain-end resonant circuit includes: a first inductor, a first capacitor and a nonlinear negative resistor, 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 the ground.

[0008] 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 second capacitor, one end of the second capacitor is connected to the ground, and the second inductor and the first inductor are coupled to each other.

[0009] 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 capacitor and the second capacitor are equal.

[0010] Furthermore, in the initial state of the sensor system, the absolute value of the nonlinear negative resistance is smaller than the resistance value of the positive resistance.

[0011] In a second aspect, the present invention further provides a detection method of the sensor system as described in any one of the first aspects, comprising the following steps:

[0012] Step 1: Adjust the value of the nonlinear negative resistance so that the absolute value of its equivalent negative resistance is smaller than the resistance of the positive resistor in the loss-end resonant circuit. At this point, the detection system is in an automatic PT symmetric state and can oscillate. 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 operates in a weak coupling state and ensures that the coupling coefficient is greater than the gain-loss coefficient.

[0013] Step 2: Measure the voltage of the gain end resonant circuit at this time as the reference voltage, recorded as V1;

[0014] Step 3: The second capacitor is adjusted by a slight change of the measured parameter, and the oscillation voltage amplitude V1' of the gain end resonant circuit is measured at this time, thereby achieving high-sensitivity detection within a 10% variation range of the measured parameter. Beneficial effects:

[0015] 1. The present invention changes the coupling coefficient between the gain-end resonant circuit and the loss-end resonant circuit by adjusting the coupling distance between the gain-end resonant circuit and the loss-end resonant circuit, so that the sensor system is in a weak coupling state, thereby 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, the second capacitor is adjusted by a slight change in the parameter to be measured, so that the voltage of the gain-end resonant circuit shows a significant increase, thereby achieving amplification of the signal to be measured.

[0016] 2. The detection method of the present invention can realize high-sensitivity wireless passive detection within a 10% variation range of the measured parameter under weak coupling conditions based on the PT symmetry principle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is an equivalent circuit diagram of a high-sensitivity sensor system based on the PT symmetry principle of the present invention.

[0018] Explanation of the marks in the figure: 1. Gain-end resonant circuit, 2. Loss-end 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 DESCRIPTION

[0019] The present invention will be further explained below with reference to the accompanying drawings.

[0020] Example 1

[0021] As shown in FIG1 , the present invention provides a highly sensitive sensor system based on the PT symmetry principle, characterized in that it includes: a gain-end resonant circuit 1 and a loss-end resonant circuit 2, wherein the gain-end resonant circuit 1 is coupled to the loss-end resonant circuit 2, and 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 the gain-end resonant circuit 1 and the loss-end resonant circuit 2, so as to ensure that the sensor system operates in a weak coupling state. In quantum mechanics, PT refers to parity-time reversal, and a system satisfying PT symmetry corresponds to an observable physical quantity. Changing the coupling distance between the gain-end resonant circuit 1 and the loss-end resonant circuit 2 is specifically achieved by adjusting the coupling distance between the first inductor 11 and the second inductor 21.

[0022] The gain-end resonant circuit 1 includes: 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 of the two ends of the first capacitor 12 is connected to the ground.

[0023] 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, the other end of the first resistor 131 is connected to the output terminal of the operational amplifier 134 and one end of the second resistor 132, one end of the second resistor 132 is connected to the output terminal of the operational amplifier 134, 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.

[0024] The loss-end resonant circuit 2 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 at both ends of the second capacitor 22. One end of the second capacitor 22 is connected to the ground. The second inductor 21 and the first inductor 11 are coupled to each other.

[0025] In the above sensor system, the gain-end resonant circuit 1 and the loss-end resonant circuit 2 realize signal transmission through mutual inductance coupling between the first inductor 11 and the second inductor 21 .

[0026] 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 first capacitor 12 and the second capacitor 22 are equal.

[0027] The specific working process of the sensor system is:

[0028] First, adjust the nonlinear negative resistance R G The absolute value is slightly smaller than the positive resistance R of the lossy resonant circuit 2 L The resistance value makes the system in an automatic PT symmetrical state and can 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.

[0029] 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 work in a weak coupling state and ensure the coupling coefficient Slightly larger than the gain loss factor where d 12 is the coupling distance, r1 is the coil radius of the first inductor 11, r2 is the coil radius of the second inductor 21, L L is the inductance value of the second inductor 21, C L is the capacitance value of the second capacitor 22, R L is the resistance value of the positive resistor 23.

[0030] The voltage of the gain end resonance circuit (1) at this time is measured as the reference voltage V1.

[0031] Finally, the second capacitor (22) is adjusted by a slight change in the parameter to be measured, and the oscillation voltage amplitude V1' at the gain end (1) is recorded. The value of V1'-V1 can reflect the change of the parameter to be measured, thereby achieving high-sensitivity detection within a range of 10% of the parameter to be measured.

[0032] Example 2

[0033] The present invention further provides a detection method of the sensor system as described in any one of Embodiment 1, comprising the following steps:

[0034] Step 1: Adjust the resistance of the nonlinear negative resistor 13 so that the absolute value of its equivalent negative resistance is smaller than the resistance of the positive resistor 23 in the loss-end resonant circuit 2. At this time, the detection system is in an automatic PT symmetric state and can oscillate. 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 operates in a weak coupling state and ensures that the coupling coefficient is greater than the gain-loss coefficient.

[0035] Step 2: Measure the voltage of the gain end resonant circuit 1 at this time as the reference voltage, recorded as V1;

[0036] Step 3: Adjust the second capacitor 22 by the slight change of the parameter to be measured, and measure the oscillation voltage amplitude V1' of the gain end resonance circuit 1 at this time. The value of V1'-V1 can reflect the change of the parameter to be measured, thereby achieving high-sensitivity detection within a range of 10% of the parameter to be measured.

[0037] To summarize, the present invention changes the coupling coefficient between the gain-end resonant circuit and the loss-end resonant circuit by adjusting the coupling distance between the gain-end resonant circuit and the loss-end resonant circuit, so that the sensor system is in a weak coupling state, thereby reducing the impact of noise on the sensor system, and 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, and at the same time, the second capacitor is adjusted by a slight change in the parameter to be measured, so that the voltage of the gain-end resonant circuit presents a significant increase, thereby realizing amplification of the signal to be measured.

[0038] The present invention also uses the detection method to achieve high-sensitivity wireless passive detection within a 10% variation range of the parameter to be measured under weak coupling conditions based on the PT symmetry principle.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A highly sensitive sensor system based on the PT symmetry principle, characterized in that, Comprising: A gain - end resonant circuit (1) and a loss - end resonant circuit (2), where 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 varying the coupling distance therebetween, so as to ensure that the sensor system operates in a weak - coupling state.

2. The highly sensitive sensor system based on the PT symmetry principle according to claim 1, characterized in that 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 two ends of the first capacitor (12), and one of the two ends of the first capacitor (12) is connected to the ground.

3. The highly sensitive sensor system based on the PT symmetry principle according to claim 2, characterized in that, The loss - end resonant circuit (2) 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 of the two ends of the second capacitor (22) is connected to the ground, and the second inductor (21) is coupled to the first inductor (11).

4. The highly sensitive sensor system based on the PT symmetry principle according to claim 3, characterized in that, When the sensor system is in the initial state, the inductance values of the first inductor (11) and the second inductor (21) are equal, and the first capacitor (12) is equal to the second capacitor (22).

5. The highly sensitive sensor system based on the PT symmetry principle according to claim 4, characterized in that, When the sensor system is in the initial state, the absolute value of the nonlinear negative resistor (13) is less than the resistance value of the positive resistor (23).

6. A detection method for the highly sensitive sensor system according to any one of claims 1-5, characterized in that, Including 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 loss - end resonant circuit (2). At this time, the detection system is in an automatic PT - symmetric state and can start to oscillate. 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 operates in a weak - coupling state and ensure that the coupling coefficient is greater than the gain - loss coefficient. Step 2: Measure the voltage of the gain - end resonant circuit (1) at this time as the reference voltage, denoted as V1. Step 3: Adjust the second capacitor (22) through the weak change of the parameter to be measured, and measure the oscillation voltage amplitude V1 of the gain-end resonant circuit (1) at this time ， , so as to achieve high-sensitivity detection within the range of 10% of the parameter to be measured

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