Phase sensor system based on nonlinear PT-symmetry principle and detection method thereof

Abstract

The application discloses a phase sensor system based on a nonlinear PT symmetry principle and a detection method thereof. The sensor system comprises: a gain end resonance circuit composed of a first inductor, a first capacitor and a nonlinear negative resistance in series; a loss end resonance circuit composed of a second inductor, a second capacitor and a positive resistance in series; and a coupling capacitor connected between the gain end resonance circuit and the loss end resonance circuit and achieving energy transmission between the two circuits. The current flowing through the gain end resonance circuit is a gain side current, and the current flowing through the loss end resonance circuit is a loss side current. High-sensitivity detection of external disturbance is realized by monitoring the phase difference between the gain side current and the loss side current. The application can realize high-sensitivity detection of a to-be-detected parameter in a wide dynamic sensitive range, and simultaneously has the characteristics of rapid response and noise suppression, thereby solving the technical problem that the existing PT symmetry sensing system is difficult to simultaneously consider a large dynamic range and high sensitivity.

Description

Technical Field

[0001] This invention belongs to the technical field of parity-time symmetric sensing systems, specifically relating to a phase sensor system and its detection method based on the nonlinear PT symmetry principle. Background Technology

[0002] In recent years, the study of non-Hermitian Hamiltonians has received widespread attention, and its theoretical framework has been successfully extended to multiple disciplines such as optics, acoustics, and electronic systems. Parity-time (PT) symmetry combines spatial and temporal inversion symmetry, revealing novel physical phenomena based on PT symmetry, such as electromagnetically induced transparency, non-directional invisibility, and robust wireless power transfer. PT-symmetric sensing systems are a novel sensing technology derived from non-Hermitian quantum mechanics, and have achieved breakthroughs in photonic crystals, microwave resonators, and MEMS oscillators, successfully applied to refractive index sensing, mass detection, and magnetic field measurement. Their circuit implementation typically consists of symmetrical coupling of gain and loss modules, achieving PT symmetry through precise control of gain and loss parameters. PT-symmetric systems exhibit modal degeneracy at singularities, resulting in superlinear response characteristics near singularities, which can significantly improve sensor sensitivity.

[0003] However, sensing technologies based on PT symmetry still face key bottlenecks: First, the stability of PT-symmetric systems is highly dependent on the balance between gain and loss; even slight influences from the sensor's environment can easily lead to PT symmetry breaking. Second, applying asymmetric perturbations to traditional linear PT-symmetric systems results in broadening of the system's characteristic spectrum and increased noise, which may mask the splitting of the system's characteristic frequencies, significantly limiting the sensor's resolution and sensitivity. Third, although currently proposed nonlinear PT-symmetric sensors offer superior sensitivity and noise performance compared to linear PT-symmetric sensors, this comes at the cost of a limited dynamic range, achieving high sensitivity only within a relatively small dynamic range. Therefore, it is essential to invent a PT-symmetric sensor detection system that combines both high sensitivity and a wide dynamic range. Summary of the Invention

[0004] The purpose of this invention is to provide a phase sensor system and its detection method based on the nonlinear PT symmetry principle, which can achieve high sensitivity detection of the parameter to be measured within a wide dynamic range, while also having fast response and noise suppression characteristics, so as to solve the technical problem that existing PT symmetric sensing systems cannot achieve both a large dynamic range and high sensitivity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a phase sensor system based on the nonlinear PT symmetry principle.

[0007] A phase sensor system based on the nonlinear PT symmetry principle includes:

[0008] The gain-end resonant circuit is composed of a first inductor, a first capacitor, and a nonlinear negative resistor connected in series.

[0009] The resonant circuit at the loss end is composed of a second inductor, a second capacitor, and a positive resistor connected in series.

[0010] The coupling capacitor is connected between the gain-end resonant circuit and the loss-end resonant circuit to realize energy transfer between the two circuits.

[0011] The current flowing through the gain-side resonant circuit is the gain-side current, and the current flowing through the loss-side resonant circuit is the loss-side current. High-sensitivity detection of external disturbances is achieved by monitoring the phase difference between the gain-side current and the loss-side current.

[0012] Furthermore, the nonlinear negative resistor is a current-controlled negative resistor, whose voltage varies with the current.

[0013] Furthermore, the nonlinear negative resistor includes an operational amplifier, a negative feedback resistor, a positive feedback resistor, and a grounding resistor, wherein: the negative feedback resistor is connected between the inverting input terminal and the output terminal of the operational amplifier, the positive feedback resistor is connected between the non-inverting input terminal and the output terminal of the operational amplifier, the non-inverting input terminal of the operational amplifier (OA) is grounded through the grounding resistor, the positive bias voltage of the operational amplifier is provided by a DC voltage source, and the negative bias voltage port is grounded.

[0014] Furthermore, the system satisfies the following relationship in its initial state to ensure that the system transitions from initial oscillation to steady state:

[0015] The inductance value of the first inductor in the gain-end resonant circuit is equal to the inductance value of the second inductor in the loss-end resonant circuit.

[0016] The capacitance value of the first capacitor in the gain-end resonant circuit is equal to the capacitance value of the second capacitor in the loss-end resonant circuit.

[0017] The absolute value of a nonlinear negative resistor is greater than the value of a positive resistor;

[0018] The initial capacitance value of the coupling capacitor makes the coupling coefficient of the system less than 1 but greater than the gain and loss coefficients.

[0019] Secondly, the present invention provides a detection method based on the phase sensor system.

[0020] A detection method based on the phase sensor system includes the following steps:

[0021] Step 1: In the initial state, adjust the inductance value of the first inductor in the gain-end resonant circuit to be equal to the inductance value of the second inductor in the loss-end resonant circuit, and the capacitance value of the first capacitor to be equal to the capacitance value of the second capacitor; adjust the resistance value of the nonlinear negative resistor so that the absolute value of its equivalent negative resistance is greater than the resistance value of the positive resistor in the loss-end resonant circuit; adjust the capacitance value of the coupling capacitor so that the system operates in a weakly coupled state.

[0022] Step 2: Measure and record the initial phase difference between the gain-side current of the gain-end circuit and the loss-side current of the loss-end circuit, denoted as φ0.

[0023] Step 3: When the second capacitor undergoes a relative change due to the change in the parameter to be measured, measure the phase difference between the gain side current and the loss side current again, and record it as φ.

[0024] Step 4, based on the relationship between the phase difference change Δφ = |φ - φ0| and the relative change of the second capacitor Δφ = μ -1 / 3 δ 1 / 3 , where μ is the coupling coefficient, and the change of the parameter to be measured is calculated.

[0025] Furthermore, in step 1, when the system is operating in a weakly coupled state, the coupling coefficient is less than 1, while ensuring that the coupling coefficient is greater than the system's gain and loss coefficients.

[0026] Furthermore, in steps 2 and 3, the phase difference is obtained by measuring the signals of the gain-side current and the loss-side current using an oscilloscope.

[0027] Furthermore, in step 4, ultra-high sensitivity detection is achieved within a 20% range of the measured parameter based on the change in phase difference.

[0028] Furthermore, the system is in a weakly coupled PT-symmetric precise region near the singular point during operation.

[0029] Unless otherwise specified, the term "PT" refers to parity time.

[0030] Beneficial effects: Compared with the prior art, the phase sensor system based on the nonlinear PT symmetry principle of the present invention has the following advantages:

[0031] 1. This invention achieves high-sensitivity detection of the relationship between phase and perturbation (the relative change in capacitance caused by a small change in the measured parameter) based on the second-order nonlinear PT symmetry principle. The sensitivity of this phase detection method is superior to that of existing PT symmetric sensors based on frequency split detection, with a sensitivity improvement of more than an order of magnitude. At the same time, this phase detection method has higher stability compared with the previously proposed amplitude detection PT symmetric sensors.

[0032] 2. The phase sensor system based on the nonlinear PT symmetry principle of this invention has a wider dynamic sensitivity range compared with traditional frequency detection methods.

[0033] 3. This invention utilizes a nonlinear gain saturation mechanism to detect the phase difference between the gain and loss signals under steady-state oscillation conditions, thereby suppressing the noise effect of the sensor.

[0034] 4. The transient characterization method used in the sensor described in this invention has short-time sensitivity and low energy consumption characteristics, which makes it more competitive in application scenarios where sensitive parameters change rapidly, such as biological detection of minute capacitance changes and precision detection in industrial environments. Attached Figure Description

[0035] Figure 1 The present invention provides an equivalent circuit diagram of a phase sensor system based on the nonlinear PT symmetry principle and its equivalent circuit diagram of a current-controlled negative resistor composed of an operational amplifier.

[0036] Explanation of markings in the diagram:

[0037] G is the gain-side resonant circuit, L is the loss-side resonant circuit, L1 is the first inductor, C1 is the first capacitor, R1 is the nonlinear negative resistor, and R... a For negative feedback resistor, R b For positive feedback resistor, R c For grounding resistance, OA is an operational amplifier, and V is... dc Forward bias voltage, V gnd L2 is the ground voltage, C2 is the second inductor, C2 is the second capacitor, R2 is the positive resistor, and C is the second capacitor. c I1 is the coupling capacitor, I2 is the gain side current, I2 is the loss side current, and δ is the relative change of the second capacitor. Detailed Implementation

[0038] The invention will now be further explained with reference to the accompanying drawings.

[0039] like Figure 1 As shown, the present invention discloses a phase sensor system based on the nonlinear PT symmetry principle, comprising a gain-end resonant circuit G, a loss-end resonant circuit L, and a coupling capacitor C. c ,in:

[0040] The gain-end resonant circuit G is composed of a first inductor L1, a first capacitor C1, and a nonlinear negative resistor R1 connected in series.

[0041] The resonant circuit L at the loss end is composed of a second inductor L2, a second capacitor C2, and a positive resistor R2 connected in series.

[0042] Coupling capacitor C cIt is connected between the gain-end resonant circuit G and the loss-end resonant circuit L, and realizes the energy transfer between the two circuits.

[0043] The current flowing through the gain-side resonant circuit G is the gain-side current I1, and the current flowing through the loss-side resonant circuit L is the loss-side current I2. High-sensitivity detection of external disturbances is achieved by monitoring the phase difference between the gain-side current I1 and the loss-side current I2.

[0044] The nonlinear negative resistor R1 is a current-controlled negative resistor, and its voltage varies with the current.

[0045] The nonlinear negative resistor R1 includes the operational amplifier OA and the negative feedback resistor R. a Positive feedback resistor R b and grounding resistance R c Where: negative feedback resistor R a The positive feedback resistor R is connected between the inverting input and output of operational amplifier OA. b Connected between the non-inverting input and output of operational amplifier OA, the non-inverting input of operational amplifier OA is connected to ground via a grounding resistor R. c Grounded, the positive bias voltage V of operational amplifier OA dc Provided by a DC voltage source, negative bias voltage V gnd The port is grounded.

[0046] The sensor system satisfies the following relationship in its initial state to ensure that the system transitions from initial oscillation to steady state:

[0047] The inductance value of the first inductor L1 in the gain-end resonant circuit G is equal to the inductance value of the second inductor L2 in the loss-end resonant circuit L.

[0048] The capacitance value of the first capacitor C1 in the gain-end resonant circuit G is equal to the capacitance value of the second capacitor C2 in the loss-end resonant circuit L.

[0049] The absolute value of the nonlinear negative resistor R1 is slightly larger than the value of the positive resistor R2;

[0050] Coupling capacitor C c The initial capacitance value makes the system coupling coefficient C c / C1 is much less than 1 but slightly greater than the gain and loss coefficients.

[0051] The detection method based on the above-described phase sensor system of the present invention includes the following steps:

[0052] Step 1: In the initial state, adjust the inductance value of the first inductor L1 in the gain-end resonant circuit G to be equal to the inductance value of the second inductor L2 in the loss-end resonant circuit L, and the capacitance value of the first capacitor C1 to be equal to the capacitance value of the second capacitor C2; adjust the resistance value of the nonlinear negative resistor R1 so that the absolute value of its equivalent negative resistance is greater than the resistance value of the positive resistor R2 in the loss-end resonant circuit L; adjust the coupling capacitor C... c The capacitance value allows the system to operate in a weakly coupled state, i.e., the system coupling coefficient μ = C. c / C1 is much less than 1, while ensuring that the coupling coefficient is slightly greater than the system gain coefficient. and loss coefficient

[0053] Step 2: Connect the current I1 of the gain circuit G and the current I2 of the loss circuit L to the two input ports of the oscilloscope at the same time, and read the initial phase difference between the current signals I1 and I2, which is denoted as φ0.

[0054] Step 3: When the second capacitor C2 changes by a relative amount δ due to a slight change in the parameter to be measured, measure the phase difference between the gain side current I1 and the loss side current I2 again, and record it as φ.

[0055] Step 4, based on the relationship between the phase difference change Δφ = |φ - φ0| and the relative change δ of the second capacitor C2, Δφ = μ -1 / 3 δ 1 / 3 This allows for ultra-high sensitivity detection within a 20% range of the measured parameter, based on the change in phase difference.

[0056] The phase sensor system based on the nonlinear PT symmetry principle of this invention consists of three parts: a loss-end (sensitive end) module composed of an inductor, a sensitive capacitor, and a positive resistor connected in series; a gain-end (readout end) module composed of an inductor, a capacitor, and a nonlinear negative resistor connected in series; and a coupling between the gain-end and loss-end modules via a capacitor. In operation, the system operates within a weakly coupled PT symmetry precision region near the singularity (EP). When the capacitance of the loss-end changes relative to external parameters due to small fluctuations, the phase difference between the current signals of the gain-end and loss-end modules is linearly related to the cube root of the relative change in capacitance, thereby amplifying the measured signal. Compared to traditional PT symmetry sensors based on frequency splitting detection, this invention offers higher sensitivity and a wider dynamic range; compared to PT symmetry sensors based on amplitude detection, it exhibits higher stability. Furthermore, the introduction of nonlinear saturation gain suppresses system noise, enabling real-time and accurate measurement of minute signals within a few microseconds of rapid response time.

[0057] In summary, this invention utilizes the nonlinear PT symmetry principle to achieve high-sensitivity detection where the phase is directly proportional to the cube root of the relative change in the sensitive capacitance. This phase detection method outperforms existing PT symmetric sensors based on frequency splitting characteristics, offering a sensitivity improvement of more than an order of magnitude and a wider dynamic sensitivity range. Simultaneously, it addresses the issue of amplitude detection methods being susceptible to power supply fluctuations, temperature changes, and device drift, exhibiting stronger anti-interference capabilities. Furthermore, the sensor employs a transient characterization method, possessing short-time sensitivity and low energy consumption, making it suitable for applications where sensitive parameters change rapidly, such as biological detection of minute capacitance changes and precision industrial environmental monitoring.

[0058] 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 phase sensor system based on the nonlinear PT symmetry principle, characterized in that: The phase sensor system includes: The gain-end resonant circuit (G) consists of the first inductor ( ), first capacitor ( ) and nonlinear negative resistance ( ) connected in series; The resonant circuit at the loss end (L) consists of a second inductor ( ), second capacitor ( ) and positive resistance ( ) connected in series; Coupling capacitor ( ), connected between the gain-end resonant circuit (G) and the loss-end resonant circuit (L), and realizes energy transfer between the two circuits; The current flowing through the gain-side resonant circuit (G) is the gain-side current ( The current flowing through the loss-side resonant circuit (L) is the loss-side current ( ), by monitoring the gain-side current ( ) and loss-side current ( The phase difference between the phases enables highly sensitive detection of external disturbances; The method includes the following steps: Step 1, in the initial state, adjust the first inductor (G) in the gain-end resonant circuit (G). The inductance value of ) and the second inductance in the loss-end resonant circuit (L) The inductance values ​​of the first capacitor ( ) are equal. The capacitance value of the first capacitor and the second capacitor ( The capacitance values ​​are equal; adjust the nonlinear negative resistor ( The resistance value is such that the absolute value of its equivalent negative resistance is greater than the positive resistance in the resonant circuit (L) at the loss end. The resistance value of the coupling capacitor () is adjusted. The capacitance value is adjusted to allow the system to operate in a weakly coupled state; Step 2, measure and record the gain-side current of the gain-side circuit (G). ) and the loss-side current of the loss-end circuit (L) The initial phase difference between them is denoted as ; Step 3, when the second capacitor ( The relative change due to the change in the measured parameter ( When ), measure the gain-side current again. ) and loss-side current ( The phase difference between them is denoted as ; Step 4, based on the phase difference change With the second capacitor ( Relative change ( The relationship between ) ,in The coupling coefficient is used to calculate the change in the measured parameter.

2. The detection method according to claim 1, characterized in that: In step 1, when the system is operating in a weakly coupled state, the coupling coefficient of the system is less than 1, while ensuring that the coupling coefficient is greater than the gain and loss coefficient of the system.

3. The detection method according to claim 1, characterized in that: In steps 2 and 3, the phase difference is measured using an oscilloscope to measure the gain-side current. ) and loss-side current ( (The signal is obtained.) 4. The detection method according to claim 1, characterized in that: In step 4, ultra-high sensitivity detection is achieved within a 20% range of the measured parameter based on the change in phase difference.

5. The detection method according to claim 1, characterized in that: The system is in a weakly coupled PT-symmetric precise region near the singular point during operation.

6. The detection method according to claim 1, characterized in that: The nonlinear negative resistance ( () is a current-controlled negative resistor, whose voltage varies with the value of the current.

7. The detection method according to claim 6, characterized in that: The nonlinear negative resistance ( This includes operational amplifiers (OA), negative feedback resistors (...). ), positive feedback resistor ( ) and grounding resistance ( ), wherein: the negative feedback resistor ( The positive feedback resistor is connected between the inverting input and output of the operational amplifier (OA). The non-inverting input of the operational amplifier (OA) is connected between its input and output terminals. The non-inverting input of the operational amplifier (OA) is connected to a grounding resistor. Grounding, the positive bias voltage of the operational amplifier (OA) The voltage is provided by a DC voltage source, and the negative bias voltage is ( The port is grounded.

8. The detection method according to claim 1, characterized in that: The system satisfies the following relationship in its initial state to ensure that the system transitions from initial oscillation to steady state: The first inductor in the gain-end resonant circuit (G) The inductance value of ) and the second inductance in the loss-end resonant circuit (L) The inductance values ​​of the two components are equal. The first capacitor in the gain-end resonant circuit (G) The capacitance value of ) and the second capacitor in the loss-end resonant circuit (L) The capacitance values ​​of the two capacitors are equal. Nonlinear negative resistance ( The absolute value of the resistance is greater than that of the positive resistance. The resistance value; Coupling capacitor ( The initial capacitance value makes the coupling coefficient of the system less than 1 but greater than the gain and loss coefficients.

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