Non-invasive blood glucose detection device based on leaky-wave antenna

Abstract

The invention discloses a leaky-wave antenna-based noninvasive blood glucose detection device, which is characterized in that the leaky-wave antenna in a traveling wave form is adopted for the first time to carry out noninvasive blood glucose continuous real-time detection, and the designed leaky-wave antenna does not generate frequency deviation when different samples are loaded; the difference of the sample concentration is mainly reflected on the amplitude change of the reflection coefficient of the antenna sensor; therefore, compared with the traditional technology, the method does not need to measure the resonant frequency and detect the resonant frequency point, so that the cost is reduced, and the detection accuracy is also improved; therefore, the method is very suitable for large-scale application and popularization in the field of blood glucose detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-invasive blood glucose detection, and in particular relates to a non-invasive blood glucose detection device based on a leaky wave antenna. Background Art

[0002] Blood glucose concentration monitoring is the main basis for the diagnosis and prognosis evaluation of diabetes. The existing technology is mainly invasive measurement methods, that is, it is necessary to first collect blood from the subject and then measure blood glucose based on the blood; this method is inefficient and can also cause trauma to the human body; therefore, more and more users choose non-invasive blood glucose measurement methods for blood glucose testing; among them, non-invasive measurement of human blood glucose concentration can be performed based on electromagnetic principles. The main principle is that blood glucose concentration will cause a change in dielectric constant (sugar concentration increases, dielectric constant decreases), and most of the electromagnetic technologies currently used for non-invasive blood glucose testing are based on resonance methods. This method is to use an electromagnetic sensor to form a capacitive coupling with the sample to be tested during the detection process; then, the glucose concentration is indirectly obtained through the shift of the sensor resonant frequency caused by the change in dielectric constant.

[0003] However, the aforementioned resonance detection method requires precise measurement of the resonant frequency of the sensor, and requires that the sensor must operate within a wide frequency band; this increases the manufacturing cost of the sensor, and the method has strict requirements on spectral resolution and sweep bandwidth, which further increases the system cost; at the same time, the sensor usually has multiple resonant modes (frequency points) on the spectrum, and each mode is generally affected by the change in the dielectric constant of the sample to be measured and produces a frequency offset, and multiple adjacent modes will also be coupled; based on this, it will be difficult to distinguish the resonant frequency points of each mode; therefore, the resonance-based blood glucose concentration measurement method must also be combined with a complex resonant frequency detection algorithm, and requires real-time detection of the resonant frequency of the sensor, which will lead to large errors; therefore, based on the aforementioned deficiencies, how to provide a low-cost and highly accurate non-invasive blood glucose detection device has become a problem that needs to be solved urgently. Summary of the Invention

[0004] The purpose of the present invention is to provide a non-invasive blood glucose detection device based on a leaky wave antenna to solve the problems of high cost and large error in the prior art.

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

[0006] In a first aspect, a non-invasive blood glucose detection device based on a leaky wave antenna is provided, comprising: a microstrip antenna layer, an isolation layer, and a wave impedance matching layer, wherein the microstrip antenna layer, the isolation layer, and the wave impedance matching layer are arranged in order from top to bottom;

[0007] A plurality of etching grooves are provided on the wave impedance matching layer, wherein the wave impedance matching layer is electrically connected to the microstrip antenna layer to form a leaky wave antenna based on the microstrip antenna layer and the plurality of etching grooves, and the leaky wave antenna is used to complete blood glucose detection, and the isolation layer is used to adjust the operating frequency of the leaky wave antenna.

[0008] Based on the above-disclosed content, the present invention provides a non-invasive blood glucose detection device based on a leaky wave antenna and based on the principle that the change in the dielectric constant of the sample to be tested affects the wave impedance matching of the leaky wave antenna. The device includes a microstrip antenna layer, an isolation layer and a wave impedance matching layer arranged in sequence from top to bottom, wherein a plurality of etching grooves are provided on the wave impedance matching layer, and the wave impedance matching layer is electrically connected to the microstrip antenna layer; in this way, the etching grooves on the wave impedance matching layer combined with the microstrip antenna layer can constitute a leaky wave antenna structure; based on this, since the leaky wave antenna is a non-resonant antenna based on a waveguide structure; therefore, the change in the dielectric constant of the sample to be tested will not cause the frequency shift of the single-port scattering coefficient of the leaky wave antenna; thus, the present invention can achieve no frequency shift after the antenna is loaded with the sample to be tested, and the change in sample concentration can be directly reflected in the change in the amplitude of the antenna reflection coefficient; therefore, the present invention can achieve real-time and continuous detection of changes in blood glucose concentration.

[0009] Through the above design, the present invention uses a traveling wave leaky wave antenna for the first time to perform non-invasive continuous real-time blood glucose detection. The designed leaky wave antenna does not cause frequency deviation when loaded with different samples. The difference in sample concentration is mainly reflected in the amplitude change of the reflection coefficient of the antenna sensor; therefore, compared with traditional technologies, the present invention does not need to measure the resonant frequency and detect the resonant frequency point, which not only reduces the cost but also improves the accuracy of detection; therefore, the present invention is very suitable for large-scale application and promotion in the field of blood glucose detection.

[0010] In one possible design, the microstrip antenna layer includes: a first dielectric plate, a microstrip line, a feeding port, and a matching resistor;

[0011] The feeding port is provided on one side of the first dielectric plate, and the matching resistor is provided on the other side of the first dielectric plate, wherein one end of the microstrip line is electrically connected to one end of the feeding port, the other end of the microstrip line is electrically connected to one end of the matching resistor, and the other end of the feeding port and the other end of the matching resistor are both electrically connected to the wave impedance matching layer.

[0012] In a possible design, the wave impedance matching layer includes a second dielectric plate, wherein the second dielectric plate is provided with the plurality of etching grooves.

[0013] In a possible design, the microstrip antenna layer includes a first dielectric board, wherein the first dielectric board and the second dielectric board are both FR-4 dielectric boards.

[0014] In a possible design, the dielectric constants of the first dielectric plate and the second dielectric plate are between 3.9 and 4.5, and the dielectric loss tangents are between 0.022 and 0.027.

[0015] In a possible design, the thickness of the first dielectric plate and the second dielectric plate is between 0.8 mm and 1.2 mm.

[0016] In a possible design, the isolation layer is a foam layer.

[0017] In a possible design, the foam layer is made of polymethacrylimide foam and has a thickness between 0.8 mm and 1.2 mm.

[0018] In a possible design, any one of the plurality of etching grooves is an I-shaped groove.

[0019] In a possible design, at least three etching grooves are provided on the wave resistance matching layer.

[0020] Beneficial effects:

[0021] (1) The present invention adopts a traveling wave leaky wave antenna for the first time to perform non-invasive continuous real-time blood glucose detection. The designed leaky wave antenna does not cause frequency deviation when loaded with different samples. The difference in sample concentration is mainly reflected in the amplitude change of the antenna sensor reflection coefficient. Therefore, compared with traditional technologies, the present invention does not need to measure the resonant frequency and detect the resonant frequency point, which not only reduces the cost but also improves the accuracy of detection. Therefore, the present invention is very suitable for large-scale application and promotion in the field of blood glucose detection.

[0022] (2) The present invention can modify the slot structure (i.e., the shape and size of the etching groove, etc.) of the leaky wave antenna and the size of each layer of the medium according to different user needs, thereby realizing real-time detection of blood glucose concentration at different operating frequencies and in different parts of the body, thereby further improving the scope of application of the present invention.

[0023] (3) The detection device provided by the present invention is small in size and low in cost, which is conducive to integration into devices such as gloves and armbands, and is easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 An equivalent circuit diagram of the conventional resonance method for measuring dielectric constant provided by an embodiment of the present invention;

[0025] Figure 2 A front view of a non-invasive blood glucose detection device based on a leaky wave antenna provided in an embodiment of the present invention;

[0026] Figure 3A side view of a non-invasive blood glucose detection device based on a leaky wave antenna provided in an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of the three-dimensional structure of a non-invasive blood glucose detection device based on a leaky wave antenna provided in an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of a wave impedance matching layer provided in an embodiment of the present invention;

[0029] Figure 6 Schematic diagram showing poor matching between the leaky wave antenna provided by an embodiment of the present invention and the sample under test;

[0030] Figure 7 Schematic diagram showing a leaky wave antenna provided by an embodiment of the present invention that is well matched to a sample under test;

[0031] Figure 8 A schematic diagram of the amplitude of the reflection coefficient of the leaky-wave antenna provided by an embodiment of the present invention when it is unloaded;

[0032] Figure 9 Schematic diagram of the change in the amplitude of the reflection coefficient when the leaky-wave antenna provided by an embodiment of the present invention is loaded with samples with different dielectric constants.

[0033] Reference numerals:

[0034] 10-microstrip antenna layer; 20-isolation layer; 30-impedance matching layer; 40-dielectric layer; 31-etched groove; 11-microstrip line; 12-feed port; 13-matching resistor. DETAILED DESCRIPTION

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly introduced below in conjunction with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0036] It should be understood that although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element without departing from the scope of the exemplary embodiments of the present invention.

[0037] It should be understood that the term "and / or" that may appear in this document is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may indicate three situations: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" that may appear in this document describes another type of association object relationship, indicating that two relationships may exist. For example, A / and B may indicate two situations: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0038] Example:

[0039] See also Figure 1 As shown, before describing the non-invasive blood glucose detection device based on leaky wave antenna provided by this embodiment, the defects of the existing resonance method for measuring blood glucose are first described; wherein, the resonance method for measuring blood glucose concentration is mainly based on the capacitive coupling between the sample to be measured and the sensor. The equivalent circuit of this method is as follows Figure 1 shown.

[0040] according to Figure 1 It can be seen that the resonant frequency f0 of the resonator when it is unloaded is as shown in the following equation (1):

[0041]

[0042] In the above equation (1), L r , C r Respectively Figure 1 The inductance value of the inductor L and the capacitance value of the capacitor C1.

[0043] When the sample is loaded, its resonant frequency f r Then it is shown in the following equation (2):

[0044]

[0045] In the above equation (2), C m It means Figure 1 The capacitance value of capacitor C2.

[0046] Based on the above formulas (1) and (2), it can be seen that the capacitive coupling between the sample to be tested and the sensor mainly affects the resonant frequency of the sensor. Therefore, when the sensor based on the resonance method is integrated into the non-invasive continuous blood glucose detection system, it is necessary to detect the resonant frequency of the sensor in real time, which requires the sensor to operate within a wide bandwidth and has strict requirements on the spectrum resolution and the sweep bandwidth. Therefore, the manufacturing cost of the entire device will increase. At the same time, the system is required to detect the resonant frequency of the sensor in real time, which will lead to a large error. In addition, since the sensor has multiple resonant modes (frequency points) on the spectrum, each mode is generally affected by the change in the dielectric constant of the sample to be tested and produces a frequency offset, and multiple adjacent modes will also be coupled, which makes it difficult to distinguish the resonant frequency points of each mode. Based on this, the system is also required to have a complex resonant frequency detection algorithm, which further increases the cost and error. Therefore, the non-invasive blood glucose detection device based on the leaky wave antenna provided in this embodiment is needed to solve the above problems.

[0047] See also Figures 2 to 5 As shown, the non-invasive blood glucose detection device based on the leaky wave antenna provided in this embodiment may include, but is not limited to: a microstrip antenna layer 10, an isolation layer 20 and a wave impedance matching layer 30; wherein, see Figure 2 and Figure 3 As shown, for example, the microstrip antenna layer 10, the isolation layer 20 and the impedance matching layer 30 can be, but are not limited to, arranged in sequence from top to bottom to constitute the aforementioned non-invasive blood glucose detection device.

[0048] Also, see Figure 4 As shown, in this embodiment, a plurality of etching grooves 31 are provided on the impedance matching layer 30, wherein the impedance matching layer 30 is electrically connected to the microstrip antenna layer 10; thus, a leaky wave antenna (i.e., a leaky wave antenna structure) can be formed based on the microstrip antenna layer 10 and the plurality of etching grooves 31; based on this, the leaky wave antenna can be used to perform blood glucose detection; specifically, its working principle is as follows: the leaky wave antenna is a non-resonant antenna based on a waveguide structure, and the change in the dielectric constant of the sample under test does not cause the frequency shift of its reflection coefficient, thereby realizing blood glucose concentration detection; that is, the part of the human body to be tested is placed below the entire device (see Figure 1 and Figure 2 As shown, Figure 1 and Figure 2 The dielectric layer 40 in the device represents the sample to be tested, that is, the part to be tested, such as a finger, etc.); then, the leaky wave antenna is fed from the microstrip antenna layer 10 to achieve signal radiation; finally, the blood glucose concentration of the human body can be determined by obtaining the amplitude of the reflection coefficient of the leaky wave antenna.

[0049] In this embodiment, the isolation layer 20 is used to adjust the operating frequency of the leaky wave antenna, and the dielectric layer 40 is equivalent to adjusting the antenna matching parameters of the leaky wave antenna when performing blood glucose detection, that is, each tested sample is different, and the corresponding matching parameters are different; based on this, by modifying the gap structure of the leaky wave antenna (that is, the shape and size of the etching groove 31, etc.) and the size of each layer of the dielectric, real-time detection of blood glucose concentration at different operating frequencies and in different parts of the body can be achieved.

[0050] Therefore, through the above explanation, the non-invasive blood glucose detection device provided in this embodiment does not need to measure the resonant frequency and detect the resonant frequency point compared to traditional technologies, which not only reduces the cost but also improves the accuracy of detection; therefore, it is very suitable for large-scale application and promotion in the field of blood glucose detection.

[0051] In a specific embodiment, one specific structure of the microstrip antenna layer 10 is disclosed below.

[0052] In a specific application, the microstrip antenna layer 10 may include, but is not limited to, a first dielectric plate, a microstrip line 11, a feeding port 12, and a matching resistor 13; wherein the connection structure of the aforementioned components is as follows:

[0053] See also Figure 4 As shown, the feeding port 12 is provided on one side of the first dielectric plate, and the matching resistor 13 is provided on the other side of the first dielectric plate, wherein one end of the microstrip line 11 is electrically connected to one end of the feeding port 12, the other end of the microstrip line 11 is electrically connected to one end of the matching resistor 13, and the other end of the feeding port 12 and the other end of the matching resistor 13 are both electrically connected to the wave impedance matching layer 30; in this way, a leaky wave antenna structure can be formed based on the aforementioned microstrip line 11, the feeding port 12, the matching resistor 13 and the plurality of etching grooves 31; specifically, when working, one port of the leaky wave antenna is fed by welding to the feeding port 12 on the microstrip line 11, and the second port is loaded by the matching resistor 12, thereby realizing signal transmission and radiating through each etching groove 31.

[0054] Optionally, for example, the transmission line characteristic impedance of the matching resistor 12 may be, but is not limited to, 50 ohms.

[0055] At the same time, for example, the wave impedance matching layer 30 includes a second dielectric plate, wherein each etching groove 31 is arranged on the second dielectric plate; optionally, for example, the first dielectric plate and the second dielectric plate are both FR-4 dielectric plates, and the dielectric constants of the two are between 3.9 and 4.5, the dielectric loss tangent is between 0.022 and 0.027, and the thickness is between 0.8 mm and 1.2 mm; further, in this embodiment, the dielectric constant of the two dielectric plates is preferably 4.3, the dielectric loss tangent is 0.025, and the thickness is 1 mm; of course, the specific structural parameters of the dielectric plate can be specifically set according to actual use, and are not limited to the above examples.

[0056] At the same time, other dielectric plates with different dielectric constants and dielectric loss tangents can also be selected, such as Rogers4003c (whose dielectric constant is 3.38 and loss tangent is 0.003); of course, if the dielectric layer material is changed, the leakage wave gap structure needs to be adjusted accordingly; it can be specifically set according to actual use and is not limited to the above examples.

[0057] In one possible design, the isolation layer 20 is, for example, a foam layer, such as polymethacrylimide foam, with a thickness between 0.8 mm and 1.2 mm. In this embodiment, the preferred foam layer is a 1 mm thick ROHACELL 31HF foam layer. Of course, the above example is only for illustration and is not specifically limited in this embodiment.

[0058] For specific applications, see Figure 5 As shown, for example, at least three etching grooves 31 are provided on the wave resistance matching layer 30, and any etching groove 31 among the several etching grooves 31 is an I-shaped groove; wherein, in this embodiment, six etching grooves 31 are preferably provided, and the six I-shaped etching grooves are to ensure that the size of the leaky wave antenna sensor is suitable for the size of a human finger within the operating frequency, thereby facilitating blood glucose detection.

[0059] Based on the above description, the overall structure of the non-invasive blood glucose detection device is as follows: two 1mm thick FR-4 (ε r=4.3, tanδ=0.025, where the aforementioned two parameters represent the dielectric constant and dielectric loss tangent, respectively), separated by a 1mm-thick ROHACELL 31HF foam layer. The top PCB forms the microstrip line, and the bottom PCB forms a ground layer with six I-shaped etched grooves. Below the ground layer is a dielectric layer (i.e., the sample under test). The foam layer can adjust the operating frequency of the sensor, and the bottom dielectric layer essentially adjusts the matching of the leaky wave antenna sensor when it is loaded. In this way, during operation, the first port of the leaky wave antenna is fed through the feed port soldered to the microstrip line, and the second port is loaded by a 50Ω matching resistor. Then, the change in the amplitude of the reflection coefficient is used to determine the blood glucose concentration.

[0060] In one possible design, this embodiment provides a matching schematic diagram of the aforementioned non-invasive blood glucose detection device; see Figure 6 and Figure 7 As shown, Figure 6 The example given is for a poorly matched case, where the energy propagates only in the leaky-wave antenna and does not enter the sample under test. Figure 7 The given example is a well-matched case, where more energy will enter the sample under test. In this way, the leaky wave antenna is a non-resonant antenna based on a waveguide structure, and the change in the dielectric constant of the sample under test will not cause the frequency shift of its reflection system. This device can directly measure the scattering coefficient S of the single-port leaky wave antenna. 11 (reflection coefficient) to derive blood glucose concentration.

[0061] In addition, this embodiment also provides a schematic diagram of the change in the amplitude of the reflection coefficient when the device is loaded with samples of different dielectric constants, where: Figure 8 is a schematic diagram of the amplitude of the reflection coefficient of the leaky wave antenna when it is unloaded. Figure 9 Schematic diagram of the change in the amplitude of the reflection coefficient when the leaky wave antenna is loaded with samples of different dielectric constants; Figure 9 It can be seen that the change in blood glucose concentration can be detected directly through the change in the amplitude of the reflection system.

[0062] Therefore, through the above detailed explanation of the present device, the present invention can achieve that no frequency deviation occurs after the antenna is loaded with the sample to be tested, and the change in sample concentration can be directly reflected in the change in the amplitude of the antenna reflection coefficient. Therefore, the present invention can continuously detect changes in blood glucose concentration in real time without measuring the resonant frequency and detecting the resonant frequency point, which not only reduces the cost but also improves the accuracy of detection; therefore, the present invention is very suitable for large-scale application and promotion in the field of blood glucose detection.

[0063] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A non-invasive blood glucose detection device based on a leaky wave antenna, characterized in that: include: A microstrip antenna layer (10), an isolation layer (20), and a wave impedance matching layer (30), wherein the microstrip antenna layer (10), the isolation layer (20), and the wave impedance matching layer (30) are arranged in sequence from top to bottom; A plurality of etching grooves (31) are provided on the impedance matching layer (30), wherein the impedance matching layer (30) is electrically connected to the microstrip antenna layer (10) to form a leaky wave antenna based on the microstrip antenna layer (10) and the plurality of etching grooves (31), and blood glucose detection is performed using the leaky wave antenna, and the isolation layer (20) is used to adjust the operating frequency of the leaky wave antenna.

2. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 1, characterized in that: The microstrip antenna layer (10) comprises: a first dielectric plate, a microstrip line (11), a feeding port (12) and a matching resistor (13); The feeding port (12) is provided on one side of the first dielectric plate, and the matching resistor (13) is provided on the other side of the first dielectric plate, wherein one end of the microstrip line (11) is electrically connected to one end of the feeding port (12), the other end of the microstrip line (11) is electrically connected to one end of the matching resistor (13), and the other end of the feeding port (12) and the other end of the matching resistor (13) are both electrically connected to the wave impedance matching layer (30).

3. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 1, characterized in that: The wave impedance matching layer (30) comprises a second dielectric plate, wherein the second dielectric plate is provided with the plurality of etching grooves (31).

4. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 3, characterized in that: The microstrip antenna layer (10) comprises a first dielectric plate, wherein the first dielectric plate and the second dielectric plate are both FR-4 dielectric plates.

5. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 4, characterized in that: The dielectric constants of the first dielectric plate and the second dielectric plate are between 3.9 and 4.5, and the dielectric loss tangents are between 0.022 and 0.

027.

6. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 4, characterized in that: The thickness of the first dielectric plate and the second dielectric plate is between 0.8 mm and 1.2 mm.

7. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 1, characterized in that: The isolation layer (20) is a foam layer.

8. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 7, characterized in that: The foam layer is made of polymethacrylimide foam and has a thickness between 0.8 mm and 1.2 mm.

9. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 1, characterized in that: Any etching groove (31) among the plurality of etching grooves (31) is an I-shaped groove.

10. The non-invasive blood glucose detection device based on leaky wave antenna according to claim 1, characterized in that: At least three etching grooves (31) are provided on the wave resistance matching layer (30).

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