Wireless sensor circuit based on non-Hermite critical point and manufacturing method

Abstract

The invention provides a wireless sensor circuit based on a non-Hermite critical point, which comprises a sensing circuit and a reading circuit, and is characterized in that the sensing circuit comprises a planar inductance coil Ls and a capacitance sensor Cs, the capacitance sensor Cs is connected with the planar inductance coil Ls in series, and the reading circuit is connected with the planar inductance coil Ls in series. The capacitive sensor Cs is constructed by adopting an interdigital electrode structure; the reading circuit comprises a planar inductance coil Lr, a capacitor element Cr, a coaxial connector and a network vector analyzer, the planar inductance coil Lr and the capacitor element Cr are connected in series, and the network vector analyzer is connected with the planar inductance coil Lr and the capacitor element Cr which are connected in series through the coaxial connector; the non-Hermite critical point of the wireless sensor circuit is a mutual inductance coupling coefficient # imgabs0 #, and the position of the reading circuit relative to the sensing circuit is characterized in that a reading side capacitor Cr, a reading side inductor Lr, a sensing side capacitor Cs, a sensing side inductor Ls, the internal resistance Rr of a reading side network vector analyzer and the resistance Rs of a sensor are substituted into an equation; the # imgabs1 # is determined according to the value of the critical point # imgabs2 # which is the mutual inductance coupling coefficient kappa. According to the wireless sensor circuit based on the non-Hermite critical point, the flexibility, the quality factor and the sensing sensitivity of the circuit design are relatively high, real-time monitoring of signals can be achieved, and the accuracy of signal reading is improved.

Description

Technical Field

[0001] The present invention relates to the field of wireless sensors, and in particular to a wireless sensor circuit based on a non-Hermitian critical point and a manufacturing method thereof. Background Art

[0002] Wireless sensors based on inductor-capacitor (LC) resonance are a type of electronic sensor devices that can simultaneously transmit energy and data through inductive coupling without the need for wire connections. Due to their compact structure and lack of power supply, they are of great significance and have broad application scenarios in many advanced and emerging technology fields, including implantable biomedical sensors, industrial sensor equipment deployed in harsh or encapsulated environments, and wireless interconnected sensor networks for the Internet of Things.

[0003] Wireless sensors based on inductor-capacitor (LC) resonance are mainly composed of a reading part and a sensing part. The capacitor in the LC resonant circuit of the sensing part is usually designed as a sensing element to detect changes in external quantities to be measured (such as physical or chemical quantities). The sensing element converts changes in the signal to be measured into changes in the capacitance in the sensing circuit, thereby causing the system resonant frequency to shift, thereby realizing detection of the signal to be measured.

[0004] Existing design solutions include traditional design architectures and parity-time symmetric design architectures. In the traditional design architecture, the reading part consists of a network vector analyzer and an inductor. The inherent loss characteristics of this traditional design architecture lead to a relatively low quality factor, and as the resistance on the sensing side increases, the quality factor will be further reduced, and the sensitivity will be relatively limited, making it difficult to accurately monitor small signals. Based on the parity-time symmetric design architecture, the reading part consists of a network vector analyzer, a resistor, an adjustable capacitor, and an inductor. During use, the reading side capacitor (C r )、Resistance(R r ) and inductance (L r ) and the sensing side capacitance (C s )、Resistance(R s ) and inductance (L s ) are strictly equal, that is, the gain parameter (g) and the loss parameter (γ) are equal g = γ, where Although this architecture can improve the quality factor of the signal and the sensitivity of the sensor near the singular point, this design architecture has the following problems. On the one hand, the strict parameter matching limits the flexibility of the sensor design; on the other hand, during the sensor test process, extra time is required to manually or through complex electrical modules to accurately adjust the adjustable capacitance of the reading part so that the size of the adjustable capacitance of the reading part is always equal to the size of the capacitance of the sensing part, which makes it difficult to achieve real-time monitoring of the signal. At the same time, since the system characteristic frequency is sensitive to all electrical parameters, the adjustment process may cause inaccuracy in the final reading signal. Summary of the invention

[0005] The present invention solves the problems of relatively low quality factor and sensing sensitivity, harsh design conditions, difficulty in achieving real-time signal monitoring, and inaccurate signal reading of existing wireless sensors based on inductor-capacitor resonance, and provides a wireless sensor circuit based on non-Hermitian critical points and a manufacturing method to solve the above problems.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides a wireless sensor circuit based on a non-Hermitian critical point, the circuit comprising a sensing circuit and a reading circuit, wherein the sensing circuit comprises: a planar inductor coil L s , Capacitive sensor C s , the capacitive sensor C s With the planar inductor L s In series, the capacitive sensor C s The interdigital electrode structure is adopted; the reading circuit includes a planar inductor coil L r , capacitor element C r , coaxial connector, network vector analyzer, the planar inductor coil L r and the capacitance element C r The network vector analyzer is connected in series with a planar inductor coil L through a coaxial connector. r and the capacitance element C r The non-Hermitian critical point of the wireless sensor circuit is the mutual inductance coupling coefficient And the position of the reading circuit relative to the sensing circuit is to place the reading side capacitor C r , reading side inductance L r , and the sensing side capacitance C s , sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation: According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

[0008] Preferably, the derivation process of the non-Hermitian critical point is: according to the coupled mode theory, the eigenvalue equation of the wireless sensor circuit system is: In the formula Where ω is the system characteristic frequency; ω0 is the natural resonant frequency of the LC resonator, the system characteristic frequency, κ is the mutual inductance coupling coefficient; g is the normalized gain parameter, γ is the normalized loss parameter, In order to obtain the critical point, let the system eigenvalue equation λ = 0, and the critical point can be obtained. The critical point only requires reading the planar inductor L in the circuit. r and the capacitance element C r The resonant frequency of the parameters and the planar inductor L in the sensing circuit s , Capacitive sensor C s The resonant frequencies are equal, that is No need to make the sensor resistor R s The internal resistance R of the network vector analyzer on the reading side r equal, that is, the gain parameter g can be greater than or less than the loss γ, and there is no need to fine-tune the reading part capacitance during the sensing process.

[0009] Preferably, the capacitive sensor is a capacitive sensor of proximity, pressure, gas, humidity, temperature, displacement, acceleration, etc. based on an interdigitated electrode structure.

[0010] Preferably, the coaxial connector is an ultra-miniature Type A interface.

[0011] The present invention also provides a method for manufacturing the wireless sensor circuit based on non-Hermitian critical point, comprising the following steps:

[0012] S1: Make the sensing circuit: Design a planar inductor coil L using a printed circuit board or flexible substrate s , and the capacitive sensor C s With the planar inductor L s Series connection;

[0013] S2: Make a reading circuit: Design a planar inductor coil L using a printed circuit board or a flexible substrate r , while the capacitor element C r With the planar inductor L r In series, the capacitor C r and planar inductor L r The parameter of is equal to the resonant frequency of the sensing circuit in S1, that is, And use a coaxial connector to connect the series capacitor element C r With the planar inductor L r Connect with network vector analyzer;

[0014] S3: Determine the placement of the read circuit: Place the read side capacitor C r , reading side inductance L r and the sensing side capacitor C s , sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

[0015] Preferably, the type of the capacitive sensor in S1 is a capacitive sensor such as proximity, pressure, gas, temperature, humidity, displacement, acceleration, etc. based on an interdigital electrode structure.

[0016] Preferably, the coaxial connector in S2 is an ultra-small type A interface.

[0017] The beneficial effects of the present invention are as follows:

[0018] The present invention provides a wireless sensor circuit based on a non-Hermitian critical point, the circuit comprising a sensing circuit and a reading circuit, wherein the sensing circuit comprises: a planar inductor coil L s , Capacitive sensor C s , the capacitive sensor C s With the planar inductor L s In series, the capacitive sensor C s The interdigital electrode structure is adopted; the reading circuit includes a planar inductor coil L r , capacitor element C r , coaxial connector, network vector analyzer, the planar inductor coil L r and the capacitance element C r The network vector analyzer is connected in series with a planar inductor coil L through a coaxial connector. r and the capacitance element C r The non-Hermitian critical point of the wireless sensor circuit is the mutual inductance coupling coefficient And the position of the reading circuit relative to the sensing circuit is to place the reading side capacitor C r , reading side inductance L r , and the sensing side capacitance C s , sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation: According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

[0019] The present invention establishes a fixed correlation between the parameters of the sensing circuit and the reading circuit. Compared with the traditional design architecture, the wireless sensor design architecture based on the non-Hermitian critical point provided by the present invention works at the critical point, and the imaginary part of the characteristic frequency is zero. Therefore, the quality factor of the sensor is significantly improved, and the sensitivity is also higher than that of the traditional architecture. When the gain parameter g approaches the loss parameter γ, the sensitivity can be further improved. Compared with the architecture based on parity symmetry, on the one hand, the wireless sensor design architecture based on the non-Hermitian critical point provided by the present invention only requires the planar inductor coil L in the reading circuit. r and the capacitance element C r The resonant frequency of the parameters and the planar inductor L in the sensing circuit s , Capacitive sensor C s The resonant frequencies are equal, that is There is no need for the gain and loss parameters and related electrical parameters to be strictly equal, which improves the flexibility of sensor design. On the other hand, during the sensing process, there is no need to spend extra time manually or through complex electrical modules to fine-tune the capacitance of the reading part to ensure the symmetry of the system, thereby achieving real-time monitoring of the signal and avoiding inaccurate readings or errors caused by fine adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 :Schematic diagram of wireless sensor circuit design based on non-Hermitian critical point. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the wireless sensor circuit and manufacturing method based on non-Hermitian critical point proposed by the present invention are further described in detail in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated in the drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0022] The circuit on the right side of the figure is a sensing circuit, including a planar inductor coil L s (Inductance is L s ), Capacitive sensor C s (The capacitance is C s, the internal resistance is R s ); The circuit on the left is the reading circuit, including: a planar inductor coil L r (Inductance is L r ), capacitor element C r (The capacitance is C r， The internal resistance is R r ), coaxial connectors, network vector analyzers.

[0023] According to the coupled mode theory, the eigenvalue equation of the circuit system in the attached figure is In the formula Where ω is the system characteristic frequency; is the natural resonant frequency of the LC resonator; κ is the mutual inductance coupling coefficient; is the normalized gain parameter; is the normalized loss parameter; C r , L r , C s , L s Read the measured capacitance and inductance and the sensing side capacitance and inductance respectively; R r is the internal resistance of the network vector analyzer on the reading side, R s is the resistance of the sensor. In order to obtain the critical point, let the system eigenvalue equation λ=0, and the critical point can be obtained.

[0024] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings. The present invention provides a wireless sensor circuit based on a non-Hermitian critical point, the circuit comprising a sensing circuit and a reading circuit, characterized in that the sensing circuit comprises: a planar inductor coil L s , Capacitive sensor C s , the capacitive sensor C s With the planar inductor L s In series, the capacitive sensor C s The interdigital electrode structure is adopted; the reading circuit includes a planar inductor coil L r , capacitor element C r , coaxial connector, network vector analyzer, the planar inductor coil L r and the capacitance element C r The network vector analyzer is connected in series with a planar inductor coil L through a coaxial connector. r and the capacitance element C r The non-Hermitian critical point of the wireless sensor circuit is the mutual inductance coupling coefficient And the position of the reading circuit relative to the sensing circuit is to place the reading side capacitor C r , reading side inductance L r , and the sensing side capacitance C s, sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation: According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

[0025] In some embodiments of the present invention, the type of the capacitive sensor is a proximity capacitive sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor is a pressure sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor is a gas pressure capacitive sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor is a temperature capacitive sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor is a humidity sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor is a displacement sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor is an acceleration sensor based on a forked electrode structure.

[0026] In some embodiments of the present invention, the coaxial connector is a SubMiniature version A (SMA) interface.

[0027] In some other embodiments of the present invention, the method for manufacturing the wireless sensor circuit based on the non-Hermitian critical point comprises the following steps:

[0028] S1: Make the sensing circuit: Design a planar inductor coil L using a printed circuit board or flexible substrate s , and the capacitive sensor C s With the planar inductor L s Series connection;

[0029] S2: Make a reading circuit: Design a planar inductor coil L using a printed circuit board or a flexible substrate r , while the capacitor element C r With the planar inductor L r In series, the capacitor C r and planar inductor L r The parameter of is equal to the resonant frequency of the sensing circuit in S1, that is, And use a coaxial connector to connect the series capacitor element C r With the planar inductor L r Connect with network vector analyzer;

[0030] S3: Determine the placement of the read circuit: Place the read side capacitor Cr , reading side inductance L r and the sensing side capacitor C s , sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

[0031] In some embodiments of the present invention, the type of the capacitive sensor in S1 is a proximity capacitive sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor in S1 is a pressure sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor in S1 is a gas pressure capacitive sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor in S1 is a temperature capacitive sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor in S1 is a humidity sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor in S1 is a displacement sensor based on a forked electrode structure; in some embodiments of the present invention, the type of the capacitive sensor in S1 is an acceleration sensor based on a forked electrode structure.

[0032] In some embodiments of the present invention, the coaxial connector in S2 is a SubMiniatureversion A (SMA) interface.

[0033] After designing and arranging according to the method in the above embodiment, the wireless sensor based on the non-Hermitian critical point can be used for sensing. When the external measured value changes, it will cause the capacitance of the sensing side to change, which will cause the characteristic frequency of the sensor to shift. According to the network vector analyzer, the corresponding reflection coefficient spectrum can be read, and the corresponding characteristic frequency can be analyzed to obtain the final test result.

[0034] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above-described embodiments only express one implementation of the present invention, and the description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A wireless sensor circuit based on a non-Hermitian critical point, the circuit comprising a sensing circuit and a reading circuit, characterized in that The sensing circuit includes: a planar inductor coil L s , Capacitive sensor C s , the capacitive sensor C s With the planar inductor L s In series, the capacitive sensor C s The interdigital electrode structure is adopted; the reading circuit includes a planar inductor coil L r , capacitor element C r , coaxial connector, network vector analyzer, the planar inductor coil L r and the capacitance element C r The network vector analyzer is connected in series with a planar inductor coil L through a coaxial connector. r and the capacitance element C r The non-Hermitian critical point of the wireless sensor circuit is the mutual inductance coupling coefficient And the position of the reading circuit relative to the sensing circuit is to place the reading side capacitor C r , reading side inductance L r , and the sensing side capacitance C s , sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation: According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

2. The wireless sensor circuit based on non-Hermitian critical point according to claim 1, characterized in that: The derivation process of the non-Hermitian critical point is as follows: According to the coupled mode theory, the eigenvalue equation of the wireless sensor circuit system is: In the formula Where ω is the system characteristic frequency; ω0 is the natural resonant frequency of the LC resonator and the system characteristic frequency, κ is the mutual inductance coupling coefficient; g is the normalized gain parameter, γ is the normalized loss parameter, In order to obtain the critical point, let the system eigenvalue equation λ = 0, and the critical point can be obtained. The critical point only requires reading the planar inductor L in the circuit. r and the capacitance element C r The resonant frequency of the parameters and the planar inductor L in the sensing circuit s , Capacitive sensor C s The resonant frequencies are equal, that is No need to make the sensor resistor R s The internal resistance R of the network vector analyzer on the reading side r equal, that is, the gain parameter g can be greater than or less than the loss γ, and there is no need to fine-tune the reading part capacitance during the sensing process.

3. A wireless sensor circuit based on non-Hermitian critical point according to claim 1 or 2, characterized in that: The type of the capacitive sensor is a capacitive sensor based on an interdigitated electrode structure for proximity, pressure, gas, humidity, temperature, displacement, acceleration, etc.

4. The wireless sensor circuit based on non-Hermitian critical point according to claim 3, characterized in that: The coaxial connector is a subminiature Type A interface.

5. The method for manufacturing a wireless sensor circuit based on a non-Hermitian critical point according to any one of claims 1 to 4, comprising the following steps: S1: Make the sensing circuit: Design a planar inductor coil L using a printed circuit board or flexible substrate s , and the capacitive sensor C s With the planar inductor L s Series connection; S2: Make a reading circuit: Design a planar inductor coil L using a printed circuit board or a flexible substrate r , while the capacitor element C r With the planar inductor L r In series, the capacitor C r and planar inductor L r The parameter of is equal to the resonant frequency of the sensing circuit in S1, that is, And use a coaxial connector to connect the series capacitor element C r With the planar inductor L r Connect with network vector analyzer; S3: Determine the placement of the read circuit: Place the read side capacitor C r , reading side inductance L r and the sensing side capacitor C s , sensor side inductance L s And the internal resistance R of the network vector analyzer on the reading side r , the sensor resistance R s Substituting into the equation: According to the mutual inductance coupling coefficient κ as the critical point The value of is determined.

6. The method for manufacturing a wireless sensor circuit based on a non-Hermitian critical point according to claim 5, characterized in that: The type of the capacitive sensor in S1 is a capacitive sensor such as proximity, pressure, gas, temperature, humidity, displacement, acceleration, etc. based on an interdigital electrode structure.

7. The method for manufacturing a wireless sensor circuit based on a non-Hermitian critical point according to claim 6 or 5, characterized in that: The coaxial connector in the S2 is an ultra-small type A interface.

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