Application of reconfigurable artificial surface plasmon polariton based microwave sensing system in measuring liquid blood glucose concentration

Abstract

The application discloses application of a microwave sensing system based on a reconfigurable artificial surface plasmon in measuring liquid blood glucose concentration. The microwave sensing system comprises a power divider, a three-order wideband coupler, an attenuator, a phase shifter and an artificial surface plasmon microwave sensor, high-Q wave trapping is realized by adjusting the attenuation value and the phase shift amount, and the detection sensitivity is improved. The sensor adopts a reconfigurable transmission line with a variable capacitance diode and an artificial local surface plasmon structure, supports multi-mode resonance and frequency tuning, and is suitable for high-sensitivity detection of liquid blood glucose concentration.

Description

Technical Field

[0001] This invention belongs to the field of microwave technology and relates to a microwave sensing system based on reconfigurable artificial surface plasmons and its application, particularly to the application of a microwave sensing system based on reconfigurable artificial surface plasmons in measuring liquid blood glucose concentration (dielectric constant). Background Technology

[0002] Diabetes is a serious disease that severely threatens people's health and normal daily life. Strictly controlling blood glucose levels within the normal range is crucial for ensuring patients' well-being. Many blood glucose measurement devices have emerged on the market, which can be mainly divided into four categories based on usage scenarios and technical approaches: home-use instant blood glucose meters (POCT, finger-prick blood glucose meters), continuous glucose monitoring systems (CGM, continuous monitoring), fully automated biochemical analyzers, glycated hemoglobin (HbA1c) analyzers, and non-invasive blood glucose meters. Among these, home-use instant blood glucose meters use electrochemical or photochemical methods to display blood glucose levels within 5-15 seconds via finger-prick blood sampling. This method is suitable for daily home monitoring, is quick and convenient, and has low consumable costs and easy operation. However, it has drawbacks such as invasiveness, susceptibility to contamination from finger-prick blood sampling, and lack of continuous monitoring. Continuous glucose monitoring systems (CGM) insert sensors subcutaneously in the upper arm / abdomen to measure interstitial fluid glucose concentration every 1-5 minutes, and the monitoring data is viewed via a mobile app. This method can continuously track fluctuations in a patient's blood glucose concentration, providing a reasonable basis for assessing the patient's diet and exercise. However, this testing method is harmful to the patient's body and has a significant impact on daily life. Fully automated biochemical analyzers separate plasma through venous blood collection and detect blood glucose concentration using an enzymatic colorimetric method. This method has the highest accuracy, but suffers from drawbacks such as expensive equipment and the need to collect large amounts of blood. Glycated hemoglobin (HbA1c) analyzers reflect long-term blood glucose levels by detecting the proportion of HbA1c to total hemoglobin in the blood, reflecting the average blood glucose level over the past 2-3 months. This method is least affected by operator technique and has high repeatability, but the detection structure is susceptible to interference from non-glucose factors. Non-invasive blood glucose meters do not require blood collection and detect blood glucose concentration using near-infrared spectroscopy, electrical impedance, and optical scattering principles, but suffer from significant detection errors. Addressing the issues of high price and limited sensitivity in existing blood glucose monitors, microwave electromagnetic sensing detection equipment, with its advantages of low price and high detection sensitivity, is playing an increasingly significant role in the detection field.

[0003] In electrical engineering, changes in blood glucose concentration reflect changes in the dielectric constant of the blood glucose solution. Therefore, microwave electromagnetic detection units are well-suited for detecting changes in blood glucose concentration due to their high sensitivity. This invention proposes using microwave electromagnetic sensing principles to detect blood glucose concentration. Currently, scholars both domestically and internationally have conducted extensive research on the design and development of high-sensitivity electromagnetic sensors, and have developed various high-sensitivity electromagnetic sensing and detection devices. These mainly include split-ring resonators (SRR), complementary split-rig resonators (CSRR), electric-LC (ELC), magnetic-LC (MLC), substrate integrated waveguide (SIW), spoof-localized surface plasmon (SLSP), and microwave hybrid resonant structures and dual-mode and multi-mode resonant sensors constructed from the above resonant units. SRR resonant sensors detect blood glucose concentration by utilizing the characteristic that the excitation electric field is mainly concentrated at the opening of the SRR. However, the SRR open resonant ring has the disadvantage of low electric field concentration. CSRR resonant sensors have an SRR resonant unit etched on the copper-clad bottom layer of the dielectric substrate. Compared to the SRR resonant unit, the CSRR resonant unit can provide better electric field confinement, and its detection sensitivity is much higher than that of the SRR resonant sensor. Overlapping a branch of a pair of SRR resonators can form an ELC resonant sensor, which can generate two-mode characteristics. Furthermore, etching the ELC resonant unit to the bottom of the dielectric substrate can form an MLC resonant sensor, which also exhibits two-mode resonance characteristics. Optimizing the design of the common gap in the middle can significantly improve the concentration of the electric field. SIW resonant sensors detect blood glucose concentration based on the TE101 master mode. According to the electric field distribution, the TE101 master mode is mainly concentrated in the middle region of the SIW resonant cavity, and this field strength mode is used to detect blood glucose concentration. SLSP sensors utilize the local electric field confinement effect brought about by the slow wave characteristics of the SLSP resonant unit to detect blood glucose concentration. The microwave sensor mentioned above mainly uses the S-parameter resonant frequency and amplitude variation characteristics to detect blood glucose concentration, but it has problems such as untunable resonant frequency and low quality factor Q value.

[0004] Therefore, there is an urgent need to develop a reconfigurable, high-Q, multimode resonant microwave sensing system to improve the sensitivity, flexibility, and practicality of detecting liquid components such as blood glucose. This invention addresses the above problems by proposing a high-Q microwave sensing system based on reconfigurable artificial surface plasmon resonances. Through structural design and circuit optimization, the resonant frequency is adjustable and the resonant peak is sharpened, thus providing a new technical path for high-precision, non-invasive blood glucose monitoring. Summary of the Invention

[0005] The main purpose of this invention is to address the shortcomings of existing technologies by proposing an application of a microwave sensing system based on reconfigurable artificial surface plasmons in measuring liquid blood glucose concentration.

[0006] This invention is implemented according to the following technical solution: This invention provides an application of a microwave sensing system based on reconfigurable artificial surface plasmons in measuring liquid blood glucose concentration. The microwave sensing system includes a dual-path control and sensing system, a vector network analyzer, and a first power divider. The application involves the vector network analyzer emitting a broadband radio frequency signal, which is split into two signals by the first power divider. Through the dual-path control and sensing system, the reference signal is precisely controlled using attenuators and phase shifters, causing it to undergo destructive interference with the sensing signal carrying sample information at the output end, constructing an equivalent notch. When changes in blood glucose concentration cause a shift in the resonant frequency of the microwave sensing system, the notch balance is broken, resulting in an amplitude change. The biochemical signal is then amplified into an electrical signal, which is finally measured by the vector network analyzer. The dual-path control and sensing system includes a first third-order broadband coupler, a second third-order broadband coupler, a first attenuator, a first phase shifter, a third third-order broadband coupler, a second power divider, a microwave sensor based on reconfigurable artificial surface plasmons, a third power divider, a second attenuator, a second phase shifter, a fourth third-order broadband coupler, a fourth power divider, and a circulator.

[0007] Preferably, the application specifically includes:

[0008] The broadband radio frequency signal emitted by the vector network analyzer is split into two paths by the first power divider, and enters the first third-order broadband coupler and the second third-order broadband coupler respectively.

[0009] The first signal output from the first power divider enters the first third-order broadband coupler. The signal output from the coupling end of the first signal sequentially enters the first attenuator, the first phase shifter, and the third third-order broadband coupler. The first power-divided input signal is output from the output end of the third third-order broadband coupler. Simultaneously, the signal output from the direct-through end of the first signal sequentially enters the second power divider, the circulator, and the reconfigurable artificial surface plasmon microwave sensor to obtain a multimode resonant signal. The multimode resonant signal is processed by the third power divider and then enters the third third-order broadband coupler. It is coupled to the output end through the coupling end to output the second power-divided input signal.

[0010] The second signal output from the first power divider enters the second-third order broadband coupler. The signal output from the direct-through end of the second signal sequentially enters the second power divider, circulator, reconfigurable artificial surface plasmon microwave sensor, third power divider, and fourth-third order broadband coupler before outputting the third power divider input signal. Simultaneously, the signal output from the coupling end of the second signal sequentially enters the second attenuator, second phase shifter, and fourth-third order broadband coupler before outputting the fourth power divider input signal.

[0011] Finally, after all the input signals from the first power divider enter the fourth power divider, they are transferred to the vector network analyzer.

[0012] Preferably, the total transmission coefficient notch level of the microwave sensing system at resonant mode one and resonant mode two is adjusted by adjusting the attenuation values ​​of the first and second attenuators and the phase shift of the first and second phase shifters.

[0013] Preferably, the microwave sensor based on reconfigurable artificial surface plasmons is stacked in sequence, comprising a feed layer, a dielectric substrate, and an artificial localized surface plasmon layer;

[0014] The feed layer includes, in sequence, an input port, an input feed port microstrip line, an input transition microstrip line, an input microstrip line, an input conversion artificial surface plasmon transmission line, a reconfigurable artificial surface plasmon transmission line, an output conversion artificial surface plasmon transmission line, an output microstrip line, an output transition microstrip line, an output feed port microstrip line, and an output port.

[0015] The artificial localized surface plasmon layer includes four sector regions distributed at the four vertices of the dielectric substrate and two artificial localized surface plasmons located at the center of the dielectric substrate; wherein, the two sector regions located in the width direction of the dielectric substrate are connected, and the two artificial localized surface plasmons are connected.

[0016] Preferably, in the reconfigurable artificial surface plasmon microwave sensor, the input conversion artificial surface plasmon transmission line includes an input trunk transmission line and multiple input conversion lines symmetrically distributed on both sides of the input trunk transmission line, wherein the multiple input conversion lines on the same side gradually increase in length from the input port to the output port and are equally spaced.

[0017] Preferably, in the reconfigurable artificial surface plasmon microwave sensor, the output conversion artificial surface plasmon transmission line and the input conversion artificial surface plasmon transmission line are axially symmetrical about the central axis of the reconfigurable artificial surface plasmon transmission line. It includes an output trunk transmission line and multiple output conversion lines axially symmetrically distributed on both sides of the output trunk transmission line. The multiple output conversion lines located on the same side gradually decrease in length from the input port to the output port and are equally spaced.

[0018] Preferably, in the reconfigurable artificial surface plasmon microwave sensor, the reconfigurable artificial surface plasmon transmission line includes a plasmon trunk transmission line and multiple plasmon conversion lines symmetrically distributed on both sides of the plasmon trunk transmission line; each plasmon conversion line has multiple staggered protrusions on both sides of the end away from the plasmon trunk transmission line, and the protrusions on the side of adjacent plasmon conversion lines closer to each other are also staggered; wherein all plasmon conversion lines located in the middle section of the plasmon trunk transmission line have a varactor diode connected in series at the end near the plasmon trunk transmission line.

[0019] Preferably, in the artificial localized surface plasmon layer, the two artificial localized surface plasmon structures are identical, each having a circular hole etched in the center of a circular metal, and multiple curved slits arranged radially outward from the circular hole; the curved slits are not connected to the circular hole.

[0020] Preferably, in the reconfigurable artificial surface plasmon microwave sensor, two artificial local surface plasmons serve as the sensing region.

[0021] The beneficial effects of the present invention include at least the following:

[0022] This invention utilizes a stacked structure in a reconfigurable artificial surface plasmon microwave sensor. The artificial localized surface plasmons (ASPs) support multimode resonance through their slow-wave characteristics, thereby improving the simultaneous detection of multiple parameters. Protrusions in the reconfigurable ASP transmission line form an interdigital capacitor structure, enhancing the coupling efficiency between the transmission line and the resonant unit, and concentrating the electric field more within the ASP region. This structure allows the sensor to excite multiple resonant modes (such as mode one and mode two) within the same frequency band, enabling the simultaneous detection of multiple parameters, including the liquid dielectric constant, thus improving the sensor's information capacity and detection efficiency.

[0023] In the reconfigurable artificial surface plasmon transmission line, a varactor diode is connected in series on the mid-section of the plasmon converter line. By changing the diode capacitance value through an external voltage, the equivalent electrical length and resonant frequency of the transmission line can be continuously adjusted, achieving tunability of the resonant frequency and enhancing the system's adaptability and optimization potential. This feature allows the sensor to actively adjust to the optimal operating frequency based on the characteristics of the sample being measured or environmental changes, overcoming the limitation of fixed resonant frequencies in traditional sensors and improving the system's applicability and performance optimizability.

[0024] This invention provides a microwave sensing system that integrates an attenuator and a phase shifter, and combines them with a third-order broadband coupler and a power divider to form a feedback control network. By adjusting the attenuation value and phase shift, the system satisfies the signal cancellation condition at the resonant frequency, achieving a deep notch (i.e., close to zero) of the total transmission coefficient S21. This significantly improves the system's quality factor (Q value), making the resonant peak sharper and more sensitive to frequency shifts, thereby enabling high-resolution detection of minute dielectric changes (such as fluctuations in blood glucose concentration).

[0025] This invention uses artificial localized surface plasmon resonances (APTs) as the sensing region, on which a PMMA film and a PTFE container form a sample cell. Because the electric field is highly concentrated in the sensing region, even minute changes in the sample's dielectric constant can cause significant changes in the resonant frequency and amplitude. Through calibration, highly sensitive, non-invasive, or minimally invasive detection of blood glucose concentration can be achieved, providing a new and feasible solution for blood glucose monitoring.

[0026] The microwave sensor of this invention utilizes a circuit system constructed with radio frequency devices such as broadband couplers, power dividers, attenuators, and phase shifters to achieve a high Q value, thereby enhancing detection sensitivity. It also has advantages such as low cost, portability, and ease of operation. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a high-Q microwave sensing system provided in an embodiment of the present invention;

[0029] Figure 2 The diagram shows the structure of a reconfigurable artificial surface plasmon microwave sensor, where (a) is the feed layer located on the top layer of the dielectric substrate, and (b) is the artificial localized surface plasmon layer located on the bottom layer of the dielectric substrate.

[0030] Figure 3 This is a view of the application of a reconfigurable artificial surface plasmon microwave sensor in liquid blood glucose monitoring;

[0031] Figure 4 This is a schematic diagram of the structure of a first-order third-order broadband coupler, where (a) is the top layer and (b) is the bottom layer;

[0032] Figure 5Let (a) be the transmission coefficient of a microwave sensor based on a reconfigurable artificial surface plasmon polariton and its application microwave sensing system, and (b) be the transmission coefficient of a high Q-value microwave sensing system.

[0033] In the diagram, the markings are: 1. First power divider; 2. First third-order broadband coupler; 2-1. Microstrip line; 2-1-1. First sub-microstrip line; 2-1-2. Second sub-microstrip line; 2-1-3. Third sub-microstrip line; 2-1-4. Fourth sub-microstrip line; 2-1-5. Fifth sub-microstrip line; 2-1-6. Sixth sub-microstrip line; 2-1-7. Seventh sub-microstrip line; 2-2. Metallic ground plane; 2-3. 50-ohm standard feed plane; 3. Second third-order broadband coupler; 4. First... 5. Attenuator; 6. First phase shifter; 7. Third-order broadband coupler; 8. Second power divider; 9. Microwave sensor based on reconfigurable artificial surface plasmon polariton; 10. Input port; 21. Input feed port microstrip line; 32. Input transition microstrip line; 43. Input microstrip line; 54. Input conversion artificial surface plasmon polariton transmission line; 55. Input trunk transmission line; 55. Input conversion line; 66. Reconfigurable artificial surface plasmon polariton transmission line; 77. -1. Isopolaron trunk transmission line; 8-6-2. Isopolaron conversion line; 8-6-2-1. Bump; 8-6-2-2. Varactor diode; 8-7. Output conversion artificial surface plasmon transmission line; 8-7-1. Output trunk transmission line; 8-7-2. Output conversion line; 8-8. Output microstrip line; 8-9. Output transition microstrip line; 8-10. Output feed port microstrip line; 8-11. Output port; 8-12. Sector; 8-13. Artificial localized surface plasmon polarization 8-13-1, Circular Hole; 8-13-2, Curved Slit; 9, Third Power Divider; 10, Second Attenuator; 11, Second Phase Shifter; 12, Fourth Third-Order Broadband Coupler; 13, Fourth Power Divider; 14, Vector Network Analyzer; 15, Circulator; 16, First 50-Ohm Load; 17, Second 50-Ohm Load; 18, Third 50-Ohm Load; 19, Fourth 50-Ohm Load; 20, PMMA Film; 21, PTFE Container; 22, Liquid Storage Chamber. Detailed Implementation

[0034] To more clearly illustrate the problems solved by the present invention, the technical solutions adopted, and the beneficial effects, the specific embodiments of the present invention are described below in conjunction with the figures. The preferred embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention. All modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be within the protection scope of the present invention.

[0035] A high-Q microwave sensing system based on reconfigurable artificial surface plasmons (ASPs) is disclosed. This microwave sensor is a system-level detection device. To further improve detection flexibility and sensitivity, this invention utilizes reconfigurable ASPs as the microwave sensing unit and constructs a high-Q network using radio frequency circuitry to achieve both flexibility and sensitivity. The microwave sensing detection system designed in this invention mainly comprises two parts: a microwave sensor 8 based on reconfigurable ASPs and a high-Q circuit network. The high-Q circuit network mainly includes a first power divider 1, a first third-order broadband coupler 2, a second third-order broadband coupler 3, a first attenuator 4, a first phase shifter 5, a third third-order broadband coupler 6, a second power divider 7, a third power divider 9, a second attenuator 10, a second phase shifter 11, a fourth third-order broadband coupler 12, a fourth power divider 13, and a circulator 15. The reconfigurable artificial surface plasmon microwave sensor 8 consists of an artificial localized surface plasmon (SSPP) transmission line and an artificial localized surface plasmon (SLSP) resonator. To improve the confinement characteristics of the electric field, an interdigital capacitor structure is embedded in the SSPP transmission line to better excite the SLSP resonator. Simultaneously, an interdigital capacitor structure is embedded in the SLSP resonator to further concentrate the electric field. Because the phase difference generated by the slow wave around the SLSP resonator is an even or odd multiple of half the wavelength, the artificial localized surface plasmon will generate multimode resonance modes. This invention mainly analyzes resonance mode one and resonance mode two. To achieve reconfigurability, a varactor diode is embedded in the SSPP transmission line. By changing the supply voltage, the capacitance value of the varactor diode is changed, thereby altering the resonant frequency. Finally, a high-Q radio frequency circuit is constructed to achieve a high notch characteristic of the transmission coefficient, thereby improving detection sensitivity.

[0036] See appendix Figure 1 This embodiment provides a microwave sensing system based on reconfigurable artificial surface plasmons, including a first power divider 1, a first third-order broadband coupler 2, a second third-order broadband coupler 3, a first attenuator 4, a first phase shifter 5, a third third-order broadband coupler 6, a second power divider 7, a microwave sensor based on reconfigurable artificial surface plasmons 8, a third power divider 9, a second attenuator 10, a second phase shifter 11, a fourth third-order broadband coupler 12, a fourth power divider 13, a vector network analyzer 14, and a circulator 15. The components are connected in sequence to form a signal processing and sensing path, which is used to realize the distribution, coupling, attenuation, phase shifting, sensing, and synthesis of broadband radio frequency signals, which are finally received and processed by the vector network analyzer 14.

[0037] Specifically, the signal transmission port of the vector network analyzer 14 is connected to the input of the first power divider 1. The two outputs of the first power divider 1 are connected to the inputs of the first third-order broadband coupler 2 and the second third-order broadband coupler 3, respectively. The coupling end of the first third-order broadband coupler 2 is connected to the input of the first attenuator 4. The output of the first attenuator 4 is connected to the input of the first phase shifter 5. The output of the first phase shifter 5 is connected to the input of the third third-order broadband coupler 6. The output of the third third-order broadband coupler 6 is connected to the first input of the fourth power divider 13. The through-hole of the first third-order broadband coupler 2 is connected to the input of the second power divider 7. The output of the second power divider 7 is connected to the input of the circulator 15. The output of the circulator 15 is connected to the reconfigurable artificial surface plasmon microwave transmission... The input terminal of sensor 8 is connected to the input terminal of the third power divider 9. The two output terminals of the third power divider 9 are connected to the coupling terminals of the third third-order broadband coupler 6 and the fourth third-order broadband coupler 12, respectively. The output terminal of the fourth third-order broadband coupler 12 is connected to the second input terminal of the fourth power divider 13. The through terminal of the second third-order broadband coupler 3 is connected to the input terminal of the second power divider 7. The coupling terminal of the second third-order broadband coupler 3 is connected to the input terminal of the second attenuator 10. The output terminal of the second attenuator 10 is connected to the input terminal of the second phase shifter 11. The output terminal of the second phase shifter 11 is connected to the input terminal of the fourth third-order broadband coupler 12. The output terminal of the fourth power divider 13 is connected to the signal receiving port of the vector network analyzer 14. The ports of the first third-order broadband coupler 2, the second third-order broadband coupler 3, the third third-order broadband coupler 6, and the fourth third-order broadband coupler 12 are also connected to the first 50-ohm load 16, the second 50-ohm load 17, the third 50-ohm load 18, and the fourth 50-ohm load 19, respectively.

[0038] This embodiment also provides the implementation process of the above-mentioned microwave sensing system, that is, its high Q value principle, including:

[0039] Step S1: The vector network analyzer 14 emits a broadband radio frequency signal, and the radio frequency signal entering the first power divider 1 can be expressed as follows: ,in and These refer to resonant mode one and resonant mode two based on the reconfigurable artificial surface plasmon microwave sensor 8, respectively; the radio frequency signal is split into two paths by the first power divider 1, and enters the first third-order broadband coupler 2 and the second third-order broadband coupler 3, respectively.

[0040] Step S2: Obtain the controllable signal by adjusting the signal path:

[0041] From the S-parameter matrix of the third-order broadband coupler, it can be seen that the first signal output from the first power divider 1 enters the first third-order broadband coupler 2, and the output signal is obtained from the coupling end. ,in and These refer to the coupling coefficient and phase change of the signal from the input to the coupling end of the third-order broadband coupler, respectively.

[0042] Next, the signal output from the first signal terminal sequentially enters the first attenuator 4, the first phase shifter 5, and the third-order broadband coupler 6. The coupled signal is obtained at the input port of the third-order broadband coupler 6, and can be represented as follows: ,in This refers to the attenuation coefficient of the first attenuator 4. This refers to the phase shift amount of the first phase shifter 5;

[0043] The first power-dividing input signal is output from the output terminal of the third-order broadband coupler 6; the expression for the first power-dividing input signal can be written as: ,in and These refer to the transmission coefficient and phase change of a third-order broadband coupler from the input to the through end, respectively.

[0044] Step S3, Sensor signal path:

[0045] The first signal output from the first power divider 1 is then passed through the second power divider 7, the circulator 15, and the reconfigurable artificial surface plasmon microwave sensor 8 to obtain a multimode resonant signal. The expression for this multimode resonant signal can be written as follows: ,in The transmission coefficient of the circulator;

[0046] The multimode resonant signal is processed by the third power divider 9. The expression of the signal after processing by the third power divider 9 can be written as follows: ,in and This refers to the transmission coefficient and phase change based on the reconfigurable artificial surface plasmon microwave sensor 8;

[0047] The multimode resonant signal, after being processed by the third power divider 9, enters the third-order broadband coupler 6, and is coupled to the output port via the coupling port to output the second power-divided input signal; the expression for the second power-divided input signal can be written as: ;

[0048] The second signal output from the first power divider 1 enters the second third-order broadband coupler 3. The signal output from the direct-through terminal of the second signal sequentially enters the second power divider 7, circulator 15, reconfigurable artificial surface plasmon microwave sensor 8, third power divider 9, and fourth third-order broadband coupler 12 before outputting the third power-divided input signal. The expression for the third power-divided input signal can be written as: ;

[0049] Step S4, Signal Synthesis and Interference:

[0050] The second signal output from the first power divider 1, after passing through the coupling terminal, sequentially enters the second attenuator 10, the second phase shifter 11, and the fourth third-order broadband coupler 12 before outputting the fourth power divider input signal; the expression for the fourth power divider input signal can be written as follows: ;

[0051] Step S5: After all the first to fourth power divider input signals enter the fourth power divider 13, the output signal expression can be written as: .

[0052] Finally, it is transferred to the Vector Network Analyzer 14.

[0053] From the output signal expression of the fourth power divider 13 in step S4, it can be seen that in order to make the total transmission coefficient of the system more deeply notched in resonant mode one and resonant mode two, i.e. It needs to meet the following requirements. ,

[0054] and,

[0055] Both of these requirements must be zero. The present invention can adjust the attenuation values ​​of the first attenuator 4 and the second attenuator 10, as well as the phase shift of the first phase shifter 5 and the second phase shifter 11, so that both of these requirements are zero, thereby adjusting the notch level of the total transmission coefficient of the microwave sensing system in resonant mode one and resonant mode two.

[0056] In one embodiment, the reconfigurable artificial surface plasmon microwave sensor 8 is stacked sequentially, comprising a feed layer, a dielectric substrate, and an artificial local surface plasmon layer.

[0057] See appendix Figure 2 In (a), the feeding layer includes, in series, an input port 8-1, an input feed port microstrip line 8-2, an input transition microstrip line 8-3, an input microstrip line 8-4, an input conversion artificial surface plasmon transmission line 8-5, a reconfigurable artificial surface plasmon transmission line 8-6, an output conversion artificial surface plasmon transmission line 8-7, an output microstrip line 8-8, an output transition microstrip line 8-9, an output feed port microstrip line 8-10, and an output port 8-11;

[0058] In one embodiment, the reconfigurable artificial surface plasmon microwave sensor 8 includes an input conversion artificial surface plasmon transmission line 8-5 comprising an input trunk transmission line 8-5-1 and multiple input conversion lines 8-5-2 symmetrically distributed on both sides of the input trunk transmission line 8-5-1. The multiple input conversion lines 8-5-2 on the same side gradually increase in length from the input port 8-1 to the output port 8-11 and are equally spaced g1. The output conversion artificial surface plasmon transmission line 8-7 is symmetrically arranged with respect to the central axis of the reconfigurable artificial surface plasmon transmission line 8-6 with respect to the input conversion artificial surface plasmon transmission line 8-5. It includes an output trunk transmission line 8-7-1 and multiple output conversion lines 8-7-2 symmetrically distributed on both sides of the output trunk transmission line 8-7-1. The multiple output conversion lines 8-7-2 on the same side gradually decrease in length from the input port 8-1 to the output port 8-11 and are equally spaced. This embodiment provides 6 sets of symmetrical input conversion lines 8-5-2 and 6 sets of symmetrical output conversion lines 8-7-2.

[0059] In one embodiment, the reconfigurable artificial surface plasmon microwave sensor 8 includes a plasmon transmission line 8-6 comprising a plasmon trunk transmission line 8-6-1 and multiple plasmon conversion lines 8-6-2 symmetrically distributed on both sides of the plasmon trunk transmission line 8-6-1. This embodiment provides 23 sets of symmetrical plasmon conversion lines 8-6-2. The end of the input trunk transmission line 8-5-1 is connected to the beginning of the plasmon trunk transmission line 8-6-1, and the end of the plasmon trunk transmission line 8-6-1 is connected to the beginning of the output trunk transmission line 8-7-1, and both are located on the same straight line.

[0060] Each polariton converter line 8-6-2 has multiple staggered protrusions 8-6-2-1 on both sides away from the polariton trunk transmission line 8-6-1. The protrusions 8-6-2-1 on the opposite side of adjacent polariton converter lines 8-6-2 are also staggered and do not contact each other, forming an interdigital capacitor structure. In this embodiment, each polariton converter line 8-6-2 has two spaced protrusions 8-6-2-1 on each side, staggered from the two protrusions 8-6-2-1 on its other side, and they do not contact each other.

[0061] All exciton conversion lines 8-6-2 located in the middle section of the exciton trunk transmission line 8-6-1 have a varactor diode 8-6-2-2 connected in series at the end near the exciton trunk transmission line 8-6-1. In this embodiment, the remaining three symmetrical exciton conversion lines 8-6-2 at each end of the exciton trunk transmission line 8-6-1 do not have varactor diodes 8-6-2-2, while the remaining 17 symmetrical exciton conversion lines 8-6-2 in the middle section have a varactor diode 8-6-2-2 connected in series at the end near the exciton trunk transmission line 8-6-1.

[0062] See appendix Figure 2 In (b), the artificial localized surface plasmon layer includes four sector regions 8-12 distributed at the four vertices of the dielectric substrate and two artificial localized surface plasmons 8-13 located at the center of the dielectric substrate, with a gap between the artificial localized surface plasmons 8-13 and the sector regions 8-12; wherein the two sector regions 8-12 located in the width direction of the dielectric substrate are connected, and the two artificial localized surface plasmons 8-13 are connected. The center-to-center distance between the two artificial localized surface plasmons 8-13 is d. The artificial localized surface plasmons constitute an artificial localized surface plasmon (SLSP) resonator.

[0063] In one embodiment, the two artificial localized surface plasmon layers 8-13 have identical structures. Each has a circular hole 8-13-1 of radius r1 etched at the center of a circular metal element, and multiple curved slits 8-13-2 radially arranged outward from the hole 8-13-1, with equidistant spacing between adjacent slits. The curved slits 8-13-2 are not connected to the hole 8-13-1. In this embodiment, each curved slit 8-13-2 has the same length, and each curved slit 8-13-2 is formed by multiple sub-slits of unequal length connected by connecting slits. Within the same curved slit 8-13-2, the sub-slits gradually increase in length outward from the hole 8-13-1, and the sub-slits are arranged parallel to each other. Each sub-slit is perpendicular to its connecting slit. In this embodiment, each artificial localized surface plasmon 8-13 has 30 curved slits 8-13-2 etched within it.

[0064] The sensor of this invention comprises a reconfigurable artificial surface plasmon polariton (ASP) microwave sensor 8 and a high-Q circuit. An ASP transmission line with an embedded interdigital structure is used to excite the ASP structure, which enhances the electric field density of the ASP resonant unit. Adding an interdigital structure to the ASP resonant unit further enhances the electric field confinement. The slow-wave characteristics of ASP generate multimode resonant modes to improve the simultaneous detection of multiple parameters. Based on the slow-wave characteristics of the reconfigurable ASP microwave sensor 8 as a resonator, two resonant modes, Mode 1 and Mode 2, are generated according to the characteristic that the phase difference formed by the slow wave around the resonator is an even or odd multiple of half the wavelength. This dual-mode characteristic allows for the detection of more parameters. A varactor diode is welded into the reconfigurable ASP transmission line 8-6 to achieve tunable resonant modes, effectively improving the sensor's reconfigurability. A high-Q circuit is constructed to achieve deeper notch filtering of the transmission coefficient, thereby improving detection sensitivity.

[0065] One embodiment is shown in the appendix. Figure 4 (a) to Appendix Figure 4In (b), the first third-order broadband coupler 2 includes a top layer, a dielectric substrate, and a bottom layer stacked sequentially. The top layer includes two microstrip lines 2-1 symmetrically arranged about the length of the dielectric substrate along the centerline axis, with a gap between them. Each microstrip line 2-1 includes a first sub-microstrip line 2-1-1, a second sub-microstrip line 2-1-2, a third sub-microstrip line 2-1-3, a fourth sub-microstrip line 2-1-4, a fifth sub-microstrip line 2-1-5, a sixth sub-microstrip line 2-1-6, and a seventh sub-microstrip line 2-1-7 connected in series. The first sub-microstrip line 2-1-1 and the seventh sub-microstrip line 2-1-7 serve as input and output terminals. The first sub-microstrip line 2-1-1 is perpendicular to the second sub-microstrip line 2-1-2, and the outer side of the connection is chamfered. The second sub-microstrip line 2-1-2 is perpendicular to the third sub-microstrip line 2-1-3, and the outer side of the connection is chamfered. Corner treatment; the fourth sub-microstrip line 2-1-4 has a U-shaped structure, with one arm perpendicular to the third sub-microstrip line 2-1-3 and the other arm perpendicular to the fifth sub-microstrip line 2-1-5. The outer sides of the connection between the fourth sub-microstrip line 2-1-4 and the third and fifth sub-microstrip lines 2-1-3 are all chamfered. The outer sides of the bottom of the two arms of the fourth sub-microstrip line 2-1-4 are also chamfered. The fifth sub-microstrip line 2-1-5 is perpendicular to the sixth sub-microstrip line 2-1-6, and the outer sides of the connection are chamfered. The sixth sub-microstrip line 2-1-6 is perpendicular to the seventh sub-microstrip line 2-1-7, and the outer sides of the connection are chamfered. The first sub-microstrip line 2-1-1, the third sub-microstrip line 2-1-3, the fifth sub-microstrip line 2-1-5, and the seventh sub-microstrip line 2-1-7 are all horizontally arranged, with the first and seventh sub-microstrip lines 2-1-1 and 2-1-7 on the same straight line, and the third and fifth sub-microstrip lines 2-1-3 on the same straight line. The two arms of the second and fourth sub-microstrip lines 2-1-2 and the sixth sub-microstrip line 2-1-6 are vertically arranged. The width of the second sub-microstrip line 2-1-2 gradually decreases from its connection point with the first sub-microstrip line 2-1-1 to its connection point with the third sub-microstrip line 2-1-3, while the width of the sixth sub-microstrip line 2-1-6 gradually increases from its connection point with the fifth and seventh sub-microstrip lines 2-1-5 to its connection point with the seventh sub-microstrip line 2-1-7. The bottom layer is a metal ground plane 2-2, covering the entire lower surface of the dielectric substrate. The two microstrip lines 2-1 at the top layer are connected to the bottom layer by a 50-ohm standard feed surface 2-3.

[0066] The second- and third-order broadband couplers 3, 6, and 12 have the same structure as the first-order broadband coupler 2.

[0067] This embodiment also provides the application of the above-described microwave sensing system in measuring liquid blood glucose concentration.

[0068] In the artificial surface plasmon microwave sensor, two artificial localized surface plasmons 8-13 serve as the sensing area.

[0069] For example, see Appendix Figure 3 When the reconfigurable artificial surface plasmon microwave sensor 8 is excited, the electric field is coupled to the two artificial localized surface plasmons 8-13 by the reconfigurable artificial surface plasmon transmission line 8-6. Therefore, a large electric field is accumulated in the region of the two artificial localized surface plasmons 8-13, which serves as the sensing area. The PMMA film 20 is placed on the surface of the two artificial localized surface plasmons 8-13. The PTFE container 21 is further placed directly above the PMMA film 20. A cuboid space is carved out in the PTFE container 21 as a liquid storage cavity 22 to hold the solution to be tested.

[0070] A microwave sensing system based on reconfigurable artificial surface plasmons for blood glucose concentration monitoring utilizes the change in the dielectric constant of the blood glucose solution to alter the resonant characteristics of the system's core sensing unit. This system employs a highly sensitive radio frequency circuit network to extract and amplify this minute change into detectable variations in the amplitude and frequency of the reflection coefficient with a dual-mode high quality factor. The implementation process can be understood as follows:

[0071] S1, Signal Generation and Path Assignment:

[0072] The vector network analyzer 14 generates a broadband radio frequency signal covering the sensor's resonant frequency. This signal first enters the first power divider 1, where it is split into two independent and coherent signals, which are then sent to the subsequent control path and sensing path, respectively.

[0073] S2, Control Signal Path:

[0074] There are two signal paths for control. One path enters the first third-order broadband coupler 2, extracts a portion of the signal from its coupling end, and passes sequentially through the first attenuator 4 and the first phase shifter 5. This path's signal does not pass through a sensor, and its amplitude and phase can be precisely preset using the attenuator and phase shifter, serving as a controllable signal. The other path enters the second third-order broadband coupler 3, extracts a portion of the signal from its coupling end, and passes sequentially through the second attenuator 10 and the second phase shifter 11. This path's signal also does not pass through a sensor, and its amplitude and phase can be precisely preset using the attenuator and phase shifter, serving as another controllable signal.

[0075] S3, Sensor signal path (carrying information about the object being measured):

[0076] The other signal is split into two branches to simultaneously excite the sensor:

[0077] Branch 1: Output from the direct-through end of the first third-order broadband coupler 2, through the second power divider 7 and circulator 15, and then into the input port of the reconfigurable artificial surface plasmon microwave sensor 8.

[0078] Branch 2: Output from the direct end of the second-third order broadband coupler 3, and also enter the sensor via the second power divider 7 and circulator 15.

[0079] Artificial localized surface plasmons 8-13 serve as the sensing region, with a container filled with blood glucose solution placed above them. The solution interacts with the strong confinement electric field near the sensor surface. Changes in blood glucose concentration lead to changes in the dielectric constant of the solution, thereby directly perturbing the sensor's resonant state, manifested as changes in the resonant frequency and amplitude of its transmission coefficients (such as the S21 parameter).

[0080] The varactor diode on the reconfigurable artificial surface plasmon transmission line 8-6 allows the resonant frequency of the sensor itself to be adjusted by an external voltage, thereby optimizing the system to the operating point most sensitive to dielectric changes.

[0081] The sensing signal carrying information about the blood glucose solution is sent out from the output port of the reconfigurable artificial surface plasmon microwave sensor 8.

[0082] S4. Signal synthesis and interference:

[0083] The signal output from the reconfigurable artificial surface plasmon microwave sensor 8 is distributed by the third power divider and then enters the third third-order broadband coupler 6 and the fourth third-order broadband coupler 12, respectively. The sensing signal carrying sample information is vector-synthesized with two signals that have been controlled by the first attenuator 4 and the first phase shifter 5, and the second attenuator 10 and the second phase shifter 11.

[0084] S5. Constructing a high-Q-value notch filter:

[0085] The aforementioned multiple signals ultimately converge at the fourth power divider 13. By precisely adjusting the attenuation of the first attenuator 4 and the second attenuator 10, and the phase shift of the first phase shifter 5 and the second phase shifter 11, destructive interference can be caused by the multiple signals at the sensor's original resonant frequency. This results in a deep notch (i.e., the transmission coefficient drops sharply to near zero) in the system's total output signal at that frequency. This process is equivalent to constructing a band-stop filter with an extremely high quality factor (Q value).

[0086] When changes in blood glucose concentration cause a slight shift in the sensor's resonant frequency, the previously precisely tuned deep notch balance condition is broken, resulting in a significant change in the amplitude of the system's total output signal at the corresponding frequency. This circuit-level interference amplification effect transforms the sensor's minute resonant frequency shift or amplitude change into a large, easily detectable change in the system's transmission coefficient (S-parameters), thereby achieving extremely high detection sensitivity.

[0087] S6. Signal Acquisition and Concentration Inversion

[0088] Finally, the synthesized signal is sent back to the vector network analyzer 14 for high-precision measurement. By monitoring the changes in the overall transmission coefficient curve of the system (especially the center frequency, depth, and shape of the notch point) and comparing it with the pre-established "blood glucose concentration-signal characteristics" calibration database, the blood glucose concentration value of the liquid to be tested can be quantitatively retrieved.

[0089] The system senses dielectric changes using a reconfigurable artificial surface plasmon microwave sensor 8. It then uses a first attenuator 4, a second attenuator 10, a first phase shifter 5, and a second phase shifter 11 to control the signal amplitude and phase relationship in a network of first third-order broadband couplers 2, second third-order broadband couplers 3, third third-order broadband couplers 6, fourth third-order broadband couplers 12, and first power dividers 1, second power dividers 7, third power dividers 9, and fourth power dividers 13. This achieves high-Q interference notch filtering at the circuit level, thereby amplifying the weak biochemical sensing signal into an easily measurable electrical signal. Finally, a vector network analyzer 14 performs precise measurements.

[0090] Preferably, the overall dimensions of the artificial surface plasmon microwave sensor provided in this embodiment are Lx=50mm and Ly=102mm. The length of the input feed port microstrip line 8-2 is 10mm and the width is 1mm. The left width of the input transition microstrip line 8-3 is 1mm, the right width is 3mm, and the length is 3.5mm. The length of the input microstrip line 8-4 is 3mm and the width is 3mm. From input port 8-1 to output port 8-11, the height of the first input conversion line 8-5-2 is 2.5mm and the width is 1mm; the height of the second input conversion line 8-5-2 is 3.5mm and the width is 1mm; the height of the third input conversion line 8-5-2 is 4.5mm and the width is 1mm; the height of the fourth input conversion line 8-5-2 is 5.5mm and the width is 1mm; the height of the fifth input conversion line 8-5-2 is 6.5mm and the width is 1mm; and the height of the sixth input conversion line 8-5-2 is 7.5mm and the width is 1mm. From input port 8-1 to output port 8-11, the height of the first set of output conversion lines 8-7-2 is 2.5mm and the width is 1mm; the height of the second set is 3.5mm and the width is 1mm; the height of the third set is 4.5mm and the width is 1mm; the height of the fourth set is 5.5mm and the width is 1mm; the height of the fifth set is 6.5mm and the width is 1mm; and the height of the sixth set is 7.5mm and the width is 1mm. The 23 sets of plasmonic transmission lines have a height of 7.5mm and a width of 1mm, and their protrusion 8-6-2-1 has a height of 1mm and a width of 0.7mm. The sector region 8-12 uses a quarter circle with a radius of 27mm. The inner and outer diameters of the artificial localized surface plasmon 8-13 are 9.1 mm and 9.5 mm, respectively, and the inner diameter of the circular hole 8-13-1 is 1.2 mm. The sub-slits of each curved slit are drawn based on radii r5=9.1 mm, r6=8.8 mm, r7=7.3 mm, r8=7 mm, r9=5.5 mm, r10=5.2 mm, r11=3.7 mm, r12=3.4 mm, r13=1.9 mm, and r14=1.5 mm. The length, width, and height of the PMMA film 20 structure are 38 mm, 50 mm, and 0.05 mm, respectively. The length, width, and height of the PTFE container 21 are 38 mm, 19 mm, and 3 mm, respectively. The length, width, and height of the liquid storage cavity 22 excavated inside the PTFE container 21 are 36 mm, 17 mm, and 3 mm, respectively.

[0091] This invention relates to a high-Q microwave sensing system based on reconfigurable artificial surface plasmons (ASPs), comprising an ASP-based sensor and a high-Q notch filter circuit. An interdigital structure is embedded in the ASP transmission line to enhance the coupling strength between the transmission line and the ASP-8-13 localized surface plasmons. Due to the slow-wave characteristics of the ASP-8-13, multimode resonant modes can be generated, effectively improving the simultaneous detection of multiple parameters in a solution. A varactor diode 8-6-2-2 is added to the ASP transmission line to improve the sensor's reconfigurability, allowing for the selection of the most sensitive mode. By adding RF circuitry such as a power divider, broadband coupler, attenuator, and phase shifter, and adjusting the attenuation value of the attenuator and the phase of the phase shifter, a deeper notch transmission coefficient can be generated to achieve the high-Q characteristic.

[0092] See appendix Figure 5 (a) Reflectance coefficient based on reconfigurable artificial surface plasmon microwave sensor 8, and attached... Figure 5 The reflection coefficient of the microwave detection system in (b) shows that at the resonant frequency, by adjusting the attenuation value and phase shift of the attenuator and phase shifter respectively, the deep-sinking and high-Q characteristics of the reflection coefficient can be achieved.

[0093] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above embodiments. Any embodiment that meets the requirements of the present invention is within the protection scope of the present invention.

Claims

1. An application of a microwave sensing system based on reconfigurable artificial surface plasmons in measuring liquid blood glucose concentration, wherein the microwave sensing system comprises a dual-path control and sensing system, a vector network analyzer (14), and a first power divider (1); characterized in that, The application involves a vector network analyzer (14) emitting a broadband radio frequency signal, which is then split into two signals by a first power divider (1). The signal is controlled by an attenuator and a phase shifter through a dual-path control and sensing system. This control causes the reference signal to interfere with the sensing signal carrying sample information at the output end, thus constructing an equivalent notch. When the change in blood glucose concentration causes the resonant frequency of the microwave sensing system to shift, the notch balance is broken, resulting in an amplitude change. The biochemical signal is then amplified into an electrical signal, which is finally measured by the vector network analyzer (14). The dual-path control and sensing includes a first third-order broadband coupler (2), a second third-order broadband coupler (3), a first attenuator (4), a first phase shifter (5), a third third-order broadband coupler (6), a second power divider (7), a reconfigurable artificial surface plasmon microwave sensor (8), a third power divider (9), a second attenuator (10), a second phase shifter (11), a fourth third-order broadband coupler (12), a fourth power divider (13), a vector network analyzer (14), and a circulator (15). The specific applications include: A broadband radio frequency signal is emitted by the vector network analyzer (14), which is split into two paths by the first power divider (1) and enters the first third-order broadband coupler (2) and the second third-order broadband coupler (3) respectively. The first signal output from the first power divider (1) enters the first third-order broadband coupler (2). The signal output from the coupling end of the first signal enters the first attenuator (4), the first phase shifter (5), and the third third-order broadband coupler (6) in sequence. The first power divider input signal is output from the output end of the third third-order broadband coupler (6). At the same time, the signal output from the direct end of the first signal enters the second power divider (7), the circulator (15), and the multimode resonant signal based on the reconfigurable artificial surface plasmon microwave sensor (8) in sequence. The multimode resonant signal is processed by the third power divider (9) and then enters the third third-order broadband coupler (6). The second power divider input signal is output from the coupling end. The second signal output from the first power divider (1) enters the second third-order broadband coupler (3). The signal output from the direct end of the second signal enters the second power divider (7), circulator (15), reconfigurable artificial surface plasmon microwave sensor (8), third power divider (9), and fourth third-order broadband coupler (12) in sequence, and then outputs the third power divider input signal. At the same time, the signal output from the coupling end of the second signal enters the second attenuator (10), second phase shifter (11), and fourth third-order broadband coupler (12) in sequence, and then outputs the fourth power divider input signal. Finally, after all the first to fourth power divider input signals enter the fourth power divider (13), they are transferred to the vector network analyzer (14).

2. The application according to claim 1, characterized in that, By adjusting the attenuation values ​​of the first attenuator (4) and the second attenuator (10), as well as the phase shift of the first phase shifter (5) and the second phase shifter (11), the total transmission coefficient of the microwave sensing system at resonant mode one and resonant mode two is adjusted.

3. The application according to claim 1, characterized in that, The reconfigurable artificial surface plasmon microwave sensor (8) consists of a feed layer, a dielectric substrate, and an artificial local surface plasmon layer stacked sequentially. The feed layer includes, in series, an input port (8-1), an input feed port microstrip line (8-2), an input transition microstrip line (8-3), an input microstrip line (8-4), an input conversion artificial surface plasmon transmission line (8-5), a reconfigurable artificial surface plasmon transmission line (8-6), an output conversion artificial surface plasmon transmission line (8-7), an output microstrip line (8-8), an output transition microstrip line (8-9), an output feed port microstrip line (8-10), and an output port (8-11). The artificial localized surface plasmon layer includes four sector regions (8-12) distributed at the four vertices of the dielectric substrate and two artificial localized surface plasmons (8-13) located at the center of the dielectric substrate; wherein, the two sector regions (8-12) located in the width direction of the dielectric substrate are connected, and the two artificial localized surface plasmons (8-13) are connected.

4. The application according to claim 3, characterized in that, In the reconfigurable artificial surface plasmon microwave sensor (8), the input conversion artificial surface plasmon transmission line (8-5) includes an input trunk transmission line (8-5-1) and multiple input conversion lines (8-5-2) symmetrically distributed on both sides of the input trunk transmission line (8-5-1). The multiple input conversion lines (8-5-2) located on the same side gradually increase in length from the input port (8-1) to the output port (8-11) and are equally spaced.

5. The application according to claim 4, characterized in that, In the reconfigurable artificial surface plasmon microwave sensor (8), the output conversion artificial surface plasmon transmission line (8-7) and the input conversion artificial surface plasmon transmission line (8-5) are symmetrically arranged about the central axis of the reconfigurable artificial surface plasmon transmission line (8-6). It includes an output trunk transmission line (8-7-1) and multiple output conversion lines (8-7-2) symmetrically distributed on both sides of the output trunk transmission line (8-7-1). The multiple output conversion lines (8-7-2) located on the same side have a gradually decreasing length from the input port (8-1) to the output port (8-11) and are equally spaced.

6. The application according to claim 3, characterized in that, In the reconfigurable artificial surface plasmon microwave sensor (8), the reconfigurable artificial surface plasmon transmission line (8-6) includes a plasmon trunk transmission line (8-6-1) and multiple plasmon conversion lines (8-6-2) symmetrically distributed on both sides of the plasmon trunk transmission line (8-6-1); each plasmon conversion line (8-6-2) has multiple staggered protrusions on both sides of the end away from the plasmon trunk transmission line (8-6-1), and the protrusions on the side closer to each other of adjacent plasmon conversion lines (8-6-2) are also staggered; all plasmon conversion lines (8-6-2) located in the middle section of the plasmon trunk transmission line (8-6-1) have a varactor diode connected in series at the end near the plasmon trunk transmission line (8-6-1).

7. The application according to claim 3, characterized in that, In the artificial localized surface plasmon layer, the two artificial localized surface plasmons (8-13) have the same structure. Each has a circular hole (8-13-1) etched in the center of a circular metal, and multiple curved slits (8-13-2) arranged radially outward from the circular hole (8-13-1). The curved slits (8-13-2) are not connected to the circular hole (8-13-1).

8. The application according to claim 3, characterized in that, In the reconfigurable artificial surface plasmon microwave sensor (8), two artificial local surface plasmons (8-13) serve as the sensing area.

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