Microwave sensor for blood coagulation detection

Abstract

The invention discloses a microwave sensor for blood coagulation detection, the microwave sensor is sequentially provided with microstrip lines, a dielectric substrate and bottom metal from top to bottom, the microstrip lines are printed on the upper surface of the dielectric substrate, the bottom metal is printed on the lower surface of the dielectric substrate, the microstrip lines comprise a first microstrip line and a second microstrip line, the first microstrip line is printed on the upper surface of the dielectric substrate, and the second microstrip line is printed on the lower surface of the dielectric substrate. The first microstrip line and the second microstrip line are symmetrically arranged along the center line of the microstrip line in the vertical direction. The microwave sensor can be applied to the aspect of biomedical detection, the plasma coagulation process is reflected through the dynamic process of plasma dielectric constant change, the instantaneity of the microwave sensor is greatly improved compared with that of traditional blood coagulation detection equipment, a blood coagulation detection result can be obtained within 3-5 minutes, and the detection accuracy is greatly improved. And the consumption of tested plasma is extremely low, and integration, miniaturization and automation are easy.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a microwave sensor for blood coagulation detection. Background Art

[0002] The coagulation mechanism plays a key role in the body's hemostasis process. Abnormalities in this mechanism can lead to serious health hazards in various areas. Coagulation is a complex physiological cascade reaction that occurs in three stages: prothrombin activation, thrombin formation, and fibrin formation. Problems in any of these three stages can lead to coagulation disorders, making it crucial to monitor the coagulation process.

[0003] Currently, there are three main methods for coagulation testing: coagulation, chromogenic substrate, and immunoturbidimetry. Coagulation is the most commonly used method, and optical and magnetic bead-based coagulation tests are more common. Optical coagulation tests have lower instrumentation costs, but they deduct the baseline turbidity of some blood samples with high cholesterol, causing the test results to deviate from the actual results. Magnetic bead-based coagulation tests use the trajectory of magnetic beads in plasma as the viscosity changes to reflect the coagulation process. However, during the movement of the magnetic beads, blood coagulation products can easily move with the beads, resulting in reduced test accuracy. Therefore, traditional coagulation tests suffer from excessive interference factors and the inability to obtain immediate test results, making them difficult to meet the demand for rapid coagulation assessment. Furthermore, traditional coagulation tests are expensive, complex, and require specialized technicians, making them difficult to meet the demand for rapid and high-precision coagulation testing. Summary of the Invention

[0004] In view of the deficiencies in the prior art, an object of the present invention is to provide a microwave sensor for blood coagulation detection.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A microwave sensor for coagulation detection, wherein the microwave sensor is provided with: a microstrip line, a dielectric substrate and a bottom metal from top to bottom, the microstrip line is printed on the upper surface of the dielectric substrate, and the bottom metal is printed on the lower surface of the dielectric substrate, the microstrip line includes: a first microstrip line and a second microstrip line, the first microstrip line and the second microstrip line are symmetrically arranged along the center line of the microstrip line in the vertical direction, the first microstrip line includes: an annular frame circuit, a first rectangular piece, a second rectangular piece, a third rectangular piece, a fourth rectangular piece, a fifth rectangular piece, a sixth rectangular piece, a seventh rectangular piece and an eighth rectangular piece, wherein the annular frame circuit is a square ring, the inner shape of the annular frame circuit is a rectangle arranged in the vertical direction in the ring, and the outer shape of the annular frame circuit is a rectangle arranged in the vertical direction in the ring, the length directions of the first rectangular piece, the second rectangular piece, the fourth rectangular piece, the sixth rectangular piece and the eighth rectangular piece are respectively arranged horizontally, and the length directions of the third rectangular piece, the fifth rectangular piece and the seventh rectangular piece are respectively arranged vertically;

[0007] The second rectangular piece is located above the annular frame circuit, the eighth rectangular piece is located below the annular frame circuit, and the second rectangular piece and the eighth rectangular piece are symmetrically arranged along the center line of the annular frame circuit in the horizontal direction;

[0008] The left edge of the second rectangular piece is connected to the upper portion of the right edge of the third rectangular piece, and the top edge of the second rectangular piece and the top edge of the third rectangular piece are located on the same horizontal line;

[0009] The left edge of the eighth rectangular piece is connected to the lower portion of the right edge of the fifth rectangular piece, and the bottom edge of the fifth rectangular piece and the bottom edge of the eighth rectangular piece are located on the same horizontal line;

[0010] The middle portion of the left edge of the annular frame circuit is connected to the right edge of the fourth rectangular piece, the left edge of the fourth rectangular piece is connected to the upper portion of the right edge of the seventh rectangular piece, the top edge of the fourth rectangular piece and the top edge of the seventh rectangular piece are located on the same horizontal line, the middle portion of the left edge of the seventh rectangular piece is connected to the right edge of the sixth rectangular piece, the lower portion of the right edge of the seventh rectangular piece is connected to the left edge of the first rectangular piece, and the bottom edge of the seventh rectangular piece and the bottom edge of the first rectangular piece are located on the same horizontal line;

[0011] The right edge of the first rectangular piece in the first microstrip line is connected to the left edge of the first rectangular piece in the second microstrip line.

[0012] In the above technical solution, the long side of the sixth rectangular piece is parallel to the long side of the dielectric substrate, and the midpoint of the short side of the sixth rectangular piece is the same as the midpoint of the short side of the dielectric substrate.

[0013] In the above technical solution, the microwave sensor for coagulation detection further includes: a flexible material layer fixed on a side of the dielectric substrate on which the microstrip line is printed, and the flexible material layer forms a hollow structure facing the detection area in the microstrip line.

[0014] In the above technical solution, the flexible material layer is made of polydimethylsiloxane (PDMS).

[0015] In the above technical solution, an SMA connector is welded to the short side of the sixth rectangular piece of the first microstrip line, and an SMA connector is welded to the short side of the sixth rectangular piece of the second microstrip line. The two SMA connectors are respectively used to connect to the vector network analyzer.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The microwave sensor of the present invention can be applied in biomedical testing. It reflects the coagulation process of plasma through the dynamic process of changes in the dielectric constant of plasma. The instantaneous performance of the present invention is greatly improved compared to traditional coagulation detection equipment. The present invention can obtain coagulation test results within 3 to 5 minutes, consumes very little plasma to be tested, and is easy to integrate, miniaturize, and automate. Compared with traditional coagulation detection methods, it can better meet people's requirements for rapid, trace, and instant coagulation detection. The present invention addresses the shortcomings of existing coagulation detection technology and focuses on improving the accuracy and speed of coagulation detection, which can play a good role in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the microwave sensor;

[0019] Figure 2 This is the dimension diagram of the microstrip line;

[0020] Figure 3 It is a structural diagram of the microstrip line;

[0021] Figure 4 is the magnetic field distribution diagram of the microstrip line;

[0022] Figure 5 This is the resonance frequency simulation diagram of the microwave sensor;

[0023] Figure 6 The simulation diagram of the resonance frequency corresponding to the simulated rabbit plasma with different dielectric constants;

[0024] Figure 7 This is the static change diagram of the center frequency under different conditions;

[0025] Figure 8 It is a real-time dynamic change diagram of the center frequency at different times;

[0026] Figure 9 Schematic diagram of the structure of the microstrip line.

[0027] Among them, 1: first rectangular piece, 2: second rectangular piece, 3: third rectangular piece, 4: fourth rectangular piece, 5: fifth rectangular piece, 6: sixth rectangular piece, 7: seventh rectangular piece, 8: eighth rectangular piece, 9: annular frame circuit. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below with reference to specific embodiments.

[0029] The copper sheet is laser cut according to the designed size to obtain the microstrip line.

[0030] In the following embodiment, the dielectric substrate is made of Rogers 4003c, and the dielectric constant of Rogers 4003c is 3.55; the length of the dielectric substrate is 30 mm, the width is 30 mm, and the thickness is 0.508 mm.

[0031] The bottom metal is a copper sheet, and the bottom metal has a length of 30 mm, a width of 30 mm, and a thickness of 0.035 mm.

[0032] The flexible material layer is made of polydimethylsiloxane (PDMS), has a length of 30 mm, a width of 12 mm, and a thickness of 1 mm, and has a hollow structure (i.e., a through hole) formed on the flexible material layer. The length of the hollow structure is 5.2 mm and the width is 3.3 mm.

[0033] Rabbit plasma was purchased from Zhengzhou Pingrui Biotechnology Co., Ltd. (Henan, China). The rabbit plasma consisted of rabbit plasma stock and sodium citrate anticoagulant. The ratio of rabbit plasma stock to sodium citrate anticoagulant was 9:1 by mass.

[0034] Activated partial thromboplastin time (APTT) assay kit was purchased from Shenyang Xiankang Medical Equipment Sales Co., Ltd. (Liaoning, China).

[0035] Electric constant temperature incubator (DH3600BⅡ, temperature control range: +5~65℃).

[0036] Vector network analyzer (ENA-E5071C, Keysight, USA).

[0037] Example 1

[0038] like Figures 1 to 3 and Figure 9As shown, a microstrip line includes: a first microstrip line and a second microstrip line, the first microstrip line and the second microstrip line are symmetrically arranged along the center line of the microstrip line in the vertical direction, the first microstrip line includes: a ring frame circuit 9, a first rectangular piece 1, a second rectangular piece 2, a third rectangular piece 3, a fourth rectangular piece 4, a fifth rectangular piece 5, a sixth rectangular piece 6, a seventh rectangular piece 7 and an eighth rectangular piece 8, wherein the ring frame circuit is a square ring, the inner shape of the ring frame circuit is a rectangle with the length direction arranged in the vertical direction, the outer shape of the ring frame circuit is a rectangle with the length direction arranged in the vertical direction, the length directions of the first rectangular piece, the second rectangular piece, the fourth rectangular piece, the sixth rectangular piece and the eighth rectangular piece are respectively arranged horizontally, and the length directions of the third rectangular piece, the fifth rectangular piece and the seventh rectangular piece are respectively arranged vertically.

[0039] The second rectangular piece is located above the annular frame circuit, the eighth rectangular piece is located below the annular frame circuit, and the second rectangular piece and the eighth rectangular piece are symmetrically arranged along the center line of the annular frame circuit in the horizontal direction;

[0040] The left edge of the second rectangular piece is connected to the upper portion of the right edge of the third rectangular piece, and the top edge of the second rectangular piece and the top edge of the third rectangular piece are located on the same horizontal line;

[0041] The left edge of the eighth rectangular piece is connected to the lower portion of the right edge of the fifth rectangular piece, and the bottom edge of the fifth rectangular piece and the bottom edge of the eighth rectangular piece are located on the same horizontal line;

[0042] The middle portion of the left edge of the annular frame circuit is connected to the right edge of the fourth rectangular piece, the left edge of the fourth rectangular piece is connected to the upper portion of the right edge of the seventh rectangular piece, the top edge of the fourth rectangular piece and the top edge of the seventh rectangular piece are located on the same horizontal line, the middle portion of the left edge of the seventh rectangular piece is connected to the right edge of the sixth rectangular piece, the lower portion of the right edge of the seventh rectangular piece is connected to the left edge of the first rectangular piece, and the bottom edge of the seventh rectangular piece and the bottom edge of the first rectangular piece are located on the same horizontal line;

[0043] The right edge of the first rectangular piece in the first microstrip line is connected to the left edge of the first rectangular piece in the second microstrip line.

[0044] The long side of the sixth rectangular piece is parallel to the long side of the dielectric substrate, and the midpoint of the short side of the sixth rectangular piece is the same as the midpoint of the short side of the dielectric substrate.

[0045] Example 2

[0046] A microwave sensor for blood coagulation detection, which is provided with: a flexible material layer ( Figure 1The flexible material is a microstrip line, a dielectric substrate, and a bottom metal layer of Example 1, wherein the microstrip line is printed (pasted) on the upper surface of the dielectric substrate, the bottom metal layer is printed (pasted) on the lower surface of the dielectric substrate, and the flexible material layer is fixed on the side of the dielectric substrate on which the microstrip line is printed (the length direction of the flexible material layer is parallel to the length direction of the dielectric substrate); the flexible material layer is formed with a hollow structure (through hole), and the hollow structure is directly opposite to the detection area in the microstrip line;

[0047] An SMA connector (not shown in the figure) is welded to the short side of the sixth rectangular piece of the first microstrip line, and an SMA connector (not shown in the figure) is welded to the short side of the sixth rectangular piece of the second microstrip line. The two SMA connectors are used to connect to the vector network analyzer respectively.

[0048] The outer rectangle of the annular frame circuit has a length of 3d and a width of g+2b. The inner rectangle of the annular frame circuit has a length of 3d-2b and a width of g. The second rectangular piece has a length of 0.5fb and a width of b. The third rectangular piece has a length of k and a width of b. The fourth rectangular piece has a length of c and a width of d. The fifth rectangular piece has a length of k and a width of b. The sixth rectangular piece has a length of W and a width of d. The seventh rectangular piece has a length of W and a width of d. The eighth rectangular piece has a length of 0.5Ld and a width of d. The distance between the bottom edge of the third rectangular piece and the top edge of the fourth rectangular piece is ak. The distance between the right edge of the annular frame circuit in the first microstrip line and the left edge of the annular frame circuit in the second microstrip line is t.

[0049] The length of the dielectric substrate is 2W+L.

[0050] The dimensions of the microstrip line are shown in Table 1.

[0051] Table 1

[0052] parameter value W 10mm d 1.1mm k 1.7mm a 2mm f 7.2mm L 10mm c 1.3mm g 0.9mm t 1mm b 0.6mm

[0053] The sample to be tested (plasma) is dropped into the detection area, and the center frequency of the microwave sensor is monitored during the experiment. Since the dielectric constant changes during the coagulation process of plasma, this change can be characterized by the center frequency, reflecting the coagulation stage corresponding to the plasma, and finally the coagulation time is obtained.

[0054] Example 3

[0055] HFSS simulation software was used to establish the structure of the bottom metal, dielectric substrate and microstrip line in Example 2 to form a microwave sensor model. The microwave sensor model was simulated under no-load state and the following results were obtained: Figure 5 The resonant frequency simulation diagram shown is Figure 5 S 11 Curve, by Figure 5 Medium S 11It can be seen from the curve that the center frequency of the microwave sensor prepared in Example 1 is 2.07 GHz.

[0056] The structure of the bottom metal, dielectric substrate and microstrip line was established using HFSS simulation software to form a microwave sensor model. The magnetic field distribution of the microstrip line at the center frequency of 2.07 GHz was calculated using HFSS simulation software. Figure 4 The magnetic field distribution diagram is as follows: Figure 4 As shown, the magnetic field strength in the middle area reaches 10,000 V / m, which is the strongest magnetic field. Therefore, the detection sensitivity of this area to surface objects is higher, and this area is determined to be the detection area. That is, the ring frame circuit in the first microstrip line and the ring frame circuit in the second microstrip line together constitute the detection area.

[0057] HFSS simulation software was used to establish the structure of the bottom metal, dielectric substrate and microstrip line to form a microwave sensor model. A dielectric object was placed in the detection area to simulate rabbit plasma. The S values ​​corresponding to different dielectric constants of the dielectric object (simulating rabbit plasma) were obtained through HFSS simulation software. 11 The S curve is obtained by making the dielectric constant ε0 equal to ε0=10, ε0=20, ε0=30, ε0=40 and ε0=50, and the S curve is obtained by making the dielectric constant ε0 equal to ε0=10, ε0=20, ε0=30, ε0=40 and ε0=50, respectively. 11 Curves, such as Figure 6 shown.

[0058] During the coagulation process, the dielectric constant of plasma will change. When the plasma is placed in the detection area of ​​the microwave sensor, the center frequency of the microwave sensor will also change due to the influence of electromagnetic effects, such as Figure 6 As shown in Figure 1, as the dielectric constant of the dielectric object increases, the center frequency of the microwave sensor shifts to the left. Therefore, changes in the coagulation state can be detected by changes in the center frequency.

[0059] Example 4

[0060] One SMA connector of the microwave sensor in Example 2 was connected to one end of a vector network analyzer via a radio frequency cable, and the other SMA connector was connected to the other end of the vector network analyzer via a radio frequency cable to form a test system for testing. The test was conducted in a sealed chamber at a temperature of 37°C, specifically including:

[0061] Rabbit plasma purchased from Zhengzhou Pingrui Biotechnology Co., Ltd. was centrifuged to obtain centrifuged rabbit plasma (the upper rabbit plasma was taken for testing), and the centrifuged rabbit plasma, ellagic acid in the activated partial thromboplastin time (APTT) assay kit, and the calcium chloride aqueous solution in the activated partial thromboplastin time (APTT) assay kit (the concentration of CaCl2 in the calcium chloride aqueous solution was 0.025 mol / L) were placed in a 37°C electric constant temperature incubator and preheated to 37°C. Then, the upper layer of the centrifuged rabbit plasma and ellagic acid were mixed (the ratio of rabbit plasma to ellagic acid was 1:1 by mass) to obtain a mixed reagent as a sample to be tested, and the calcium chloride aqueous solution was used as a coagulation detection reagent to perform the following test:

[0062] Test 1: Take 10μL of mixed reagent at 37℃ and drop it into the detection area of ​​the microstrip line. Use vector network analyzer to obtain the S value corresponding to the first second after adding the mixed reagent. 11 curve( Figure 7 After 10 seconds of adding the mixed reagent, 10 μL of 37°C calcium chloride aqueous solution was added to the detection area. The vector network analyzer was used to obtain the plasma concentration of the calcium chloride aqueous solution after 1 second ( Figure 7 "Drip CaCl2 solution"), 10s( Figure 7 in "After Drip 10s"), 20s( Figure 7 "After Drip 20s"), 30s ( Figure 7 "After Drip 30s") and 40s ( Figure 7 S in "After Drip 40s" 11 The curve is obtained as Figure 7 The center frequency static change diagram is shown.

[0063] Depend on Figure 7 It can be seen that the S corresponding to the first second of adding calcium chloride aqueous solution is 11 The center frequency of the curve is relative to the S corresponding to the first second of adding the mixed reagent. 11 The center frequency of the curve shifts to the left, indicating that the dielectric constant of rabbit plasma increases. The S 11 The center frequency of the curve is relative to the S corresponding to the first second of adding calcium chloride aqueous solution. 11 The center frequency of the curve gradually shifts to the right, indicating that the dielectric constant of rabbit plasma gradually decreases, that is, the plasma state is changing. The S values ​​corresponding to the 30th and 40th seconds after the addition of calcium chloride aqueous solution are 11 The center frequency of the curve remains stable, indicating that the coagulation process has been completed.

[0064] Test 2: Take 10μL of 37℃ mixed reagent and drip it into the detection area of ​​the microstrip line. 10 seconds after adding the mixed reagent, add 10μL of 37℃ calcium chloride aqueous solution. Record the change of the center frequency of the microwave sensor during the whole process and get Figure 8 The center frequency real-time dynamic change diagram is shown. Figure 8 The middle horizontal axis -10s represents the time when the mixed reagent is added dropwise, and 0s represents the time when the calcium chloride aqueous solution is added dropwise.

[0065] During the coagulation process of plasma, soluble fibrinogen will be converted into insoluble fibrin. The structural change of protein will affect the dielectric constant of plasma. In addition, the water in plasma will be absorbed by the coagulated fibrin network, resulting in a decrease in water content, which in turn causes the overall dielectric constant of plasma to decrease during the coagulation process. Figure 8 It can be seen that the center frequency of the microwave sensor drops sharply within 1 second of adding the calcium chloride solution. As time goes by, the center frequency of the microwave sensor begins to increase, indicating that the dielectric constant of the plasma begins to decrease, that is, the plasma begins to coagulate. The center frequency of the microwave sensor tends to stabilize after about 25 seconds of adding the calcium chloride solution, indicating that the dielectric constant has stopped changing and the plasma has completed coagulation. Figure 8 It can be seen that the time from the beginning of plasma coagulation to the end of coagulation is about 25 seconds, while the plasma coagulation time measured by the activated partial thromboplastin time (APTT) assay kit is 22 to 38 seconds. The plasma coagulation time measured by the microwave sensor of the present invention is consistent with the conventional monitoring time, indicating that the microwave sensor has a high correlation with traditional coagulation monitoring equipment.

[0066] The present invention has good test results, simple structure, low cost, easy production, convenient test process, and can realize real-time detection, and has important practical value in the field of coagulation detection.

[0067] The above is an exemplary description of the present invention. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by other skilled in the art without expending creative labor falls within the scope of protection of the present invention.

Claims

1. A microstrip line, characterized in that: include: The first microstrip line and the second microstrip line are symmetrically arranged along the center line of the microstrip line in the vertical direction. The first microstrip line comprises: an annular frame circuit (9), a first rectangular piece (1), a second rectangular piece (2), a third rectangular piece (3), a fourth rectangular piece (4), a fifth rectangular piece (5), a sixth rectangular piece (6), a seventh rectangular piece (7) and an eighth rectangular piece (8). The annular frame circuit (9) is a square ring. The inner shape of the annular frame circuit (9) is a rectangle with its length arranged in the vertical direction. The outer shape of the annular frame circuit (9) is a rectangle with its length arranged in the vertical direction. The length directions of the first rectangular piece (1), the second rectangular piece (2), the fourth rectangular piece (4), the sixth rectangular piece (6) and the eighth rectangular piece (8) are respectively arranged horizontally, and the length directions of the third rectangular piece (3), the fifth rectangular piece (5) and the seventh rectangular piece (7) are respectively arranged vertically. The second rectangular piece (2) is located above the annular frame circuit (9), the eighth rectangular piece (8) is located below the annular frame circuit (9), and the second rectangular piece (2) and the eighth rectangular piece (8) are symmetrically arranged along the horizontal center line of the annular frame circuit (9); The left edge of the second rectangular piece (2) is connected to the upper portion of the right edge of the third rectangular piece (3), and the top edge of the second rectangular piece (2) and the top edge of the third rectangular piece (3) are located on the same horizontal line; The left edge of the eighth rectangular piece (8) is connected to the lower portion of the right edge of the fifth rectangular piece (5), and the bottom edge of the fifth rectangular piece (5) and the bottom edge of the eighth rectangular piece (8) are located on the same horizontal line; The middle portion of the left edge of the annular frame circuit (9) is connected to the right edge of the fourth rectangular piece (4), the left edge of the fourth rectangular piece (4) is connected to the upper portion of the right edge of the seventh rectangular piece (7), the top edge of the fourth rectangular piece (4) and the top edge of the seventh rectangular piece (7) are located on the same horizontal line, the middle portion of the left edge of the seventh rectangular piece (7) is connected to the right edge of the sixth rectangular piece (6), the lower portion of the right edge of the seventh rectangular piece (7) is connected to the left edge of the first rectangular piece (1), and the bottom edge of the seventh rectangular piece (7) and the bottom edge of the first rectangular piece (1) are located on the same horizontal line; The right side edge of the first rectangular piece (1) in the first microstrip line is connected to the left side edge of the first rectangular piece (1) in the second microstrip line.

2. A microwave sensor for blood coagulation detection, characterized in that: The microwave sensor is provided with: the microstrip line according to claim 1, a dielectric substrate and a bottom metal in sequence from top to bottom, the microstrip line is printed on the upper surface of the dielectric substrate, and the bottom metal is fixed on the lower surface of the dielectric substrate.

3. The microwave sensor according to claim 2, characterized in that The long side of the sixth rectangular piece (6) is parallel to the long side of the dielectric substrate, and the midpoint of the short side of the sixth rectangular piece (6) is the same as the midpoint of the short side of the dielectric substrate.

4. The microwave sensor according to claim 3, characterized in that The microwave sensor further comprises a flexible material layer fixed on one side of the dielectric substrate where the microstrip line is fixed. The flexible material layer is formed with a hollow structure facing the detection area in the microstrip line.

5. The microwave sensor according to claim 4, characterized in that The flexible material layer is made of polydimethylsiloxane.

6. The microwave sensor according to claim 3, characterized in that The material of the dielectric substrate is Rogers 4003c, and the dielectric constant of Rogers 4003c is 3.

55.

7. The microwave sensor according to claim 3, characterized in that The bottom metal is copper sheet.

8. The microwave sensor according to claim 3, characterized in that The first microstrip line mid-ring frame circuit (9) and the second microstrip line mid-ring frame circuit (9) together form a detection area.

9. Use of the microwave sensor according to any one of claims 1 to 8 in detecting changes in the dielectric constant of a liquid.

10. The use according to claim 9, characterized in that As the dielectric constant of the liquid increases, the S 11 The center frequency of the curve decreases.

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