Capillary microchannel-based drive-free terahertz metamaterial sensor

Abstract

The present application relates to a kind of based on capillary microchannel driven terahertz metamaterial sensor, belong to the technical field of metamaterial sensor, the metal part of the present application forms self-suction microchannel channel, without additional processing, from structural design, naturally form microflow channel, the processing difficulty is substantially reduced to zero, greatly reduce the processing difficulty and save processing cost;The microflow channel of the present application makes the measured liquid directly contact, so that the change of electromagnetic field regulated by the metamaterial metal structure can directly act on the measured object, and the sensitivity of the metamaterial sensor can be maximized;The amount of measured liquid required by the microflow channel of the present application is extremely low, in the order of μL, and can be used for microflow solution detection, and the small amount of liquid can reduce the absorption of solution, especially water solution, to terahertz, can increase the detection range and enhance the reliability of detection result.

Description

Technical Field

[0001] This invention relates to the field of metamaterial sensor technology, and more specifically to a driverless terahertz metamaterial sensor based on capillary microchannels. Background Technology

[0002] Terahertz (THz) waves typically refer to electromagnetic radiation in the frequency range of 0.1 THz to 10 THz. They are characterized by their transient nature, low photon energy, high transmittance, and broadband bandwidth. Terahertz waves offer high resolution and can directly or indirectly detect information about matter. Metamaterials are artificial composite materials composed of periodically arranged arrays of subwavelength structural units, usually consisting of a metallic structure and a substrate material. They exhibit excellent electromagnetic response characteristics in the terahertz band. The electromagnetic response of metamaterials changes with the electromagnetic properties of their environment (the material covering the metamaterial surface), manifested in the frequency and amplitude variations of the metamaterial's response curve. Terahertz metamaterial sensors are a crucial application of metamaterials, offering advantages such as label-free operation, high sensitivity, and speed. Furthermore, metamaterial sensors require minimal analytes and can be used for trace substance detection. Combining terahertz wave detection technology with the narrow linewidth of metamaterials can further improve the resolution and sensitivity of terahertz detection technology, enabling the detection of minute changes in the sample. Metamaterial-based sensors are characterized by their sensitivity, label-free nature, simplicity, and rapid detection capabilities, and are widely used in biomedical detection and substance-specific detection.

[0003] In existing metamaterial sensors, the samples tested are usually solid (dry). For solution samples, especially aqueous solutions, the measurement of aqueous solutions and suspensions is challenging due to water's strong absorption of terahertz waves. Existing reports commonly use liquid measurement methods including: (A) Metal-out-of-plane microchannel metamaterial sensors: Additional microchannels are fabricated on the surface of the metal layer of the metamaterial. This method is difficult and costly to fabricate, and the liquid being measured cannot directly contact the metal. Furthermore, the dielectric constant of the material used to construct the microchannels and the SU-8 photoresist covering the metamaterial surface is 4.8, which reduces the sensitivity of the metamaterial sensor. (B) Substrate-out-of-plane microchannel metamaterial sensors: Microchannel structures are fabricated on the substrate side of the metamaterial sensor. This method is less difficult and less costly, but the substrate material separates the metal structure of the metamaterial from the microchannels, preventing the sensor from reaching its full sensitivity. (C) Microcavity and metamaterial combined sensor chip: A liquid cavity capable of holding hundreds of micrometers is bonded to the metal side of the metamaterial to form a metamaterial sensor chip. This method is low-cost and easy to process, but the liquid thickness is usually in the range of tens to hundreds of micrometers, which has a large absorption of terahertz. The thicker liquid will reduce the sensitivity of the sensor and require a large sample.

[0004] In summary, existing metamaterial sensors for measuring liquids (especially aqueous solutions) have drawbacks such as low sensitivity, high manufacturing difficulty, or large sample requirements, which cannot meet the sensitive measurement needs of trace aqueous solutions. Summary of the Invention

[0005] In view of the above problems, this invention provides a driverless terahertz metamaterial sensor based on capillary microchannels. The channel isolated in the metamaterial layer by a metal unit array structure serves as a capillary microchannel. The capillary effect of the liquid allows it to self-fill the microchannel, achieving driverless flow. The natural microchannels formed by the metamaterial's metal portion require no additional processing. Through structural design, the naturally formed microchannels reduce the processing difficulty to virtually zero, significantly lowering processing complexity and saving costs.

[0006] This invention provides a driverless terahertz metamaterial sensor based on capillary microchannels, comprising:

[0007] The metamaterial layers and microcavity structures are connected sequentially from top to bottom along the vertical direction;

[0008] The connection between the metamaterial layer and the microcavity structure is detachable, allowing for reuse.

[0009] The metamaterial layer includes a metal unit array structure 2, a capillary microfluidic channel 4, and a first substrate 1; the capillary microfluidic channel 4 is a channel isolated by the metal unit array structure 2 in the metamaterial layer.

[0010] The capillary microfluidic channel utilizes the capillary phenomenon of liquids to allow the liquid to fill the microfluidic channel on its own, achieving a flow of liquid without driving force.

[0011] Optionally, the microcavity structure includes a first microfluidic channel 5, a second microfluidic channel 8, a solution inlet channel 6, and a solution outlet channel 7;

[0012] The first microfluidic channel 5 and the second microfluidic channel 8 are respectively connected to the bottom and top of the metal unit array structure, and are used to connect multiple unit capillary microchannels;

[0013] The solution inlet channel 6 is connected to the first microfluidic channel 5 and adopts a stepped structure to maximize the guidance of liquid into the microfluidic channel.

[0014] The solution outlet channel 7 is connected to the second microfluidic channel 8 to ensure that the microfluidic channel is connected to the air, which is a necessary condition for capillary self-priming.

[0015] Optionally, the metal unit array structure includes multiple metal units 3, which are periodically arranged on the first substrate to form capillary microfluidic channels 4.

[0016] The metal unit 3 includes a metal frame 3-1, a metal frame 3-2, and a unit capillary microfluidic channel 3-3;

[0017] The first metal frame and the second metal frame are centrally symmetrical, forming a unit capillary microfluidic channel 3-3 in the middle.

[0018] Optionally, each metal unit 3 is uniformly distributed along the horizontal and vertical directions, wherein, along the vertical direction, the capillary microfluidic channels of each unit are aligned and connected to form a multi-column metal unit structure; the multi-column metal unit structure is arranged in an equally spaced column to form a metal unit array structure.

[0019] Optionally, the outer contours of the metal frame 3-1 and the metal frame 3-2 are rectangular;

[0020] The inner contours of the metal frame 3-1 and the metal frame 3-2 are regular geometric shapes composed of horizontal and vertical straight lines.

[0021] Optionally, the first microfluidic channel 5 is vertically connected to the solution inlet channel 6, and the solution inlet channel is arranged in a vertical direction;

[0022] The first microfluidic channel 5 connects to multiple unit capillary microfluidic channels at the top of the metal unit array structure.

[0023] Optionally, the second microfluidic channel includes channel one 8-1 and channel two 8-2;

[0024] Channel 1 8-1 is perpendicularly connected to Channel 2 8-2. Channel 2 is also connected to Solution Outlet Channel 7. Solution Outlet Channel 7 is arranged parallel to Channel 1 8-1.

[0025] The solution outlet channel 7 is arranged horizontally;

[0026] Channel 8-1 connects multiple unit capillary microfluidic channels at the bottom of the metal unit array structure.

[0027] Alternatively, nanoantennas or plasmonic structures can be embedded within capillary microfluidic channels.

[0028] Optionally, the nanoantenna is a dipole antenna or a metamaterial structure;

[0029] The dipole antenna is a metal nanorod or a V-shaped antenna, which can directionally enhance the radiation and reception of terahertz waves.

[0030] Optionally, the material of metal unit 3 is metallic gold.

[0031] Compared with the prior art, the present invention has at least the following beneficial effects:

[0032] (1) The metamaterial of the present invention is composed of chemically stable metallic gold and fused silica glass with low dielectric constant, which ensures the stability of the electromagnetic response characteristics of the metamaterial and also ensures that the sensitivity of the metamaterial is fully utilized.

[0033] (2) The natural microfluidic channels formed by the metamaterial metal part of the present invention do not require additional processing. Starting from the structural design, the naturally formed microfluidic channels have no driving force, simplify the equipment, and have a compact structure, which reduces the processing difficulty to almost zero, greatly reducing the processing difficulty and saving the processing cost.

[0034] (3) The microfluidic channel of the present invention allows the liquid to be measured to come into direct contact, so that the change of electromagnetic field controlled by the metamaterial metal structure can be directly applied to the object to be measured, and the sensitivity of the metamaterial sensor can be maximized.

[0035] (4) The microfluidic channel of the present invention requires a very low amount of liquid to be tested, on the order of microliters (μL), which can be used for the detection of microfluidic solutions. At the same time, the small amount of liquid can reduce the absorption of terahertz by the solution, especially the aqueous solution, which can increase the detection range and enhance the reliability of the detection results.

[0036] (5) The capillary structure formed by combining metamaterials and microcavities in this invention can absorb liquids on its own due to capillary action, without the need for additional pumping devices. This reduces the complexity of the metamaterial sensor test structure, and the simple structure also helps to ensure the stability of the device.

[0037] (6) The width of the microfluidic channel of the present invention is on the order of micrometers and the depth is on the order of hundreds of nanometers, which can accommodate the passage of biological macromolecules. This sensor chip is specially designed for biological macromolecule solutions.

[0038] (7) The metamaterial layer and microcavity of the present invention are detachable and reusable. Attached Figure Description

[0039] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0040] Figure 1 This is a schematic diagram of the structure of the undriven terahertz metamaterial sensor based on capillary microchannels of the present invention;

[0041] Figure label:

[0042] Second substrate 1, metal unit array structure 2, metal unit 3, metal frame one 3-1, metal frame two 3-2, unit capillary microfluidic channel 3-3, capillary microfluidic channel 4, first microfluidic channel 5, solution inlet channel 6, solution inlet 6-1, solution outlet channel 7, channel one 8-1, channel two 8-2, second substrate 9. Detailed Implementation

[0043] To better understand the above-described objectives, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0044] A specific embodiment of the present invention, such as Figure 1 A driverless terahertz metamaterial sensor based on capillary microchannels is disclosed, comprising: a metamaterial layer and a microcavity structure connected sequentially from top to bottom along the vertical direction;

[0045] Optionally, the connection between the metamaterial layer and the microcavity structure is a detachable connection, enabling reuse;

[0046] Optionally, the metamaterial layer includes a metal unit array structure 2, a capillary microfluidic channel 4, and a first substrate 1; the capillary microfluidic channel 4 is a channel isolated by the metal unit array structure 2 in the metamaterial layer;

[0047] The capillary microfluidic channel utilizes the capillary phenomenon of liquids to allow the liquid to fill the microfluidic channel on its own, achieving a flow of liquid without driving force.

[0048] Optionally, the metal unit array structure includes multiple metal units 3, which are periodically arranged on the first substrate to form capillary microfluidic channels 4.

[0049] Optionally, the metal unit 3 includes a metal frame 3-1, a metal frame 3-2, and a unit capillary microfluidic channel 3-3;

[0050] The outer contours of the metal frame 3-1 and the metal frame 3-2 are rectangular.

[0051] The inner contours of the metal frame 3-1 and the metal frame 3-2 are regular geometric shapes composed of horizontal and vertical straight lines.

[0052] The first metal frame and the second metal frame are centrally symmetrical, with a unit capillary microfluidic channel 3-3 formed in the middle;

[0053] Optionally, each metal unit 3 is uniformly distributed along the horizontal and vertical directions, wherein, along the vertical direction, the capillary microfluidic channels of each unit are aligned and connected to form a multi-column metal unit structure; the multi-column metal unit structure is arranged in an equally spaced column to form a metal unit array structure.

[0054] Optionally, the metal unit array structure 3 is arranged in a row, with a size of 100×100;

[0055] Optionally, the material of the first substrate is a polished silicon wafer or fused silica glass;

[0056] Furthermore, the material of the metal unit 3 is metallic gold, which not only has a high electrical conductivity σ = 4.561 × 107 S / m, but also has stability, is not easily oxidized at the hundred-nanometer level, and does not react with the analyte, thus ensuring the stability of the electromagnetic response characteristics of the metamaterial.

[0057] Furthermore, the material of the first substrate is fused silica glass, which not only has good transmittance for terahertz waves, but also has a low dielectric constant of 1.75. The low dielectric constant of the substrate is beneficial to fully utilize the sensitivity of the metamaterial sensor.

[0058] Optionally, the microcavity structure includes a cavity structure, a first microfluidic channel 5, a second microfluidic channel 8, a solution inlet channel 6, a solution outlet channel 7, and a second substrate 9;

[0059] The first microfluidic channel 5 and the second microfluidic channel are respectively connected to the bottom and top of the metal unit array structure, and are used to connect multiple unit capillary microfluidic channels;

[0060] The solution inlet channel 6 is connected to the first microfluidic channel 5 and adopts a stepped structure to maximize the guidance of liquid into the microfluidic channel;

[0061] The solution outlet channel 7 is connected to the second microfluidic channel 8 to ensure that the microfluidic channel is connected to the air, which is a necessary condition for capillary self-priming.

[0062] Optionally, the second substrate 9 is a hollow rectangle, and the cavity structure, the first microfluidic channel 5, the solution inlet channel 6, the solution outlet channel 7, and the second microfluidic channel 8 are all disposed on the second substrate, forming a seal by atmospheric pressure and van der Waals force to prevent liquid leakage.

[0063] Optionally, the metal unit array structure is embedded in the cavity structure.

[0064] The first and second microfluidic channels are connected to the cavity structure, and their function is to prevent liquid from overflowing after the microcavity structure and metamaterial structure are combined.

[0065] Optionally, the first microfluidic channel 5 is vertically connected to the solution inlet channel 6, and the solution inlet channel is arranged in a vertical direction;

[0066] The first microfluidic channel 5 connects to multiple unit capillary microfluidic channels at the top of the metal unit array structure.

[0067] Optionally, the second microfluidic channel includes channel one 8-1 and channel two 8-2;

[0068] Channel 1 8-1 is perpendicularly connected to Channel 2 8-2. Channel 2 is also connected to Solution Outlet Channel 7. Solution Outlet Channel 7 is arranged parallel to Channel 1 8-1.

[0069] The solution outlet channel 7 is arranged horizontally;

[0070] Channel 8-1 connects multiple unit capillary microfluidic channels at the bottom of the metal unit array structure. Optionally, the first microfluidic channel 5, the second microfluidic channel 8, the solution inlet channel 6, and the solution outlet channel 7 are made of gold.

[0071] Optionally, after the metamaterial layer is bonded and assembled with the microcavity structure, its outer contour is seamlessly connected to the outer contour of the metal unit array structure.

[0072] The second substrate is connected to the cavity structure and the microfluidic channel 5;

[0073] It is understandable that the second substrate serves as a support for the cavity structure and microfluidic channel 5, which are attached to the second substrate 9 through micro-nano fabrication technology; after the second substrate 9 and the first substrate 1 are bonded and moistened, they form a sealing effect due to atmospheric pressure.

[0074] Furthermore, the patterned structure composed of metallic gold within the microcavity structure surrounds the metamaterial metallic structure array pattern, with annular channels reserved around the perimeter serving as microfluidic channels, forming a complete capillary self-absorption structure. Notably, the depth of the capillary microfluidic channels is the same as the thickness of the metallic gold.

[0075] This invention achieves undriven capillary self-absorption + terahertz electromagnetic response. The liquid transport is undriven: after the liquid is dropped into the solution inlet channel 6, the capillary phenomenon of spontaneous flow of liquid in the micron / nanoscale channel due to surface tension is realized. The liquid fills the capillary microfluidic channel and the microfluidic channel of the microcavity structure by itself. No driving pump is required throughout the process. The sealing design of the microcavity structure, combined with atmospheric pressure and van der Waals force after the fit, ensures that the liquid does not leak out.

[0076] In this invention, terahertz waves are incident perpendicularly, first passing through a microcavity structure, then incident on a metamaterial layer, and finally exiting. The metallic unit array of the metamaterial exhibits characteristic electromagnetic responses to terahertz waves, such as resonant frequency and transmittance. When the capillary microfluidic channel is filled with the solution to be tested, the refractive index, concentration, and other properties of the solution alter the electromagnetic environment surrounding the metamaterial, thereby modulating the transmission characteristics of the terahertz wave, such as resonant peak frequency shift and intensity change. By detecting the changes in the terahertz wave, sensitive measurements of the solution properties can be achieved.

[0077] In this invention, the metamaterial metal structure can naturally form capillary channels, which are formed through the design of the metal structure, without the need for additional processing in the microfluidic channels.

[0078] Optionally, the expression for the depth of the microfluidic channel is:

[0079] h=k1·w n +k2

[0080] wherein, h is the depth, k1 is a constant related to liquid properties, k2 is a constant related to the surface energy of the material, n is an exponential term that generally satisfies 0<n<1, and w is the width.

[0081] Optionally, the capillary microfluidic channel has the same depth and width as the first microfluidic channel and the second microfluidic channel;

[0082] The solution inlet channel (6) and the solution outlet channel (7) have the same depth and width as the capillary microfluidic channel;

[0083] Optionally, the width of the first microfluidic channel is 4 μm to 6 μm, which can accommodate biomacromolecules to pass through, and the sensor chip is specially designed for biomacromolecule solutions;

[0084] Optionally, the depth of the first microfluidic channel is 80 nm, 100 nm, 200 nm or 300 nm.

[0085] Further, the metal unit array structure is attached to the microcavity structure to form a self-priming terahertz metamaterial sensor chip, which realizes sensitive measurement of trace solutions.

[0086] Optionally, the order of magnitude of the trace solution is microliter (μL);

[0087] Optionally, the metal unit array structure (2) is completely enclosed by the microfluidic channel (5);

[0088] The liquid is dropped on the solution inlet (6-1), and the solution is sucked into the microfluidic channel by itself due to capillary action.

[0089] The solution outlet is used to ensure that the microfluidic channel is communicated with air, so as to ensure the feasibility of self-priming via capillary action.

[0090] In an example, the depth of the capillary microfluidic channel is 80 to 300 nm, and the width of the capillary microfluidic channel is on the order of micrometers; by utilizing the capillary phenomenon of liquid, the liquid can automatically fill the channel without a driving pump.

[0091] Optionally, nano-antennas or plasmonic structures are embedded in the capillary microfluidic channel, which significantly enhances the interaction between terahertz waves and biomolecules, breaks through the limitations of sensitivity and resolution, improves the coupling efficiency between terahertz waves and biomolecules, and realizes high-sensitivity detection at the sub-wavelength scale.

[0092] Further, the nano-antenna is a dipole antenna or a metamaterial structure;

[0093] The dipole antenna is a metal nanorod or a V-shaped antenna, which can directionally enhance the radiation and reception of terahertz waves.

[0094] The metamaterial structure is a fractal structure or a fishnet structure, achieving a wide-band electromagnetic response.

[0095] Furthermore, the nanoantenna material is metallic gold, metallic silver, or graphene;

[0096] Optionally, plasmon structures can be embedded in capillary microfluidic channels;

[0097] For example, an array of nanoparticles or a periodic metal grating is deposited on the inner wall of a capillary microfluidic channel.

[0098] Optionally, 3D-printed plasmonic metamaterials can be embedded within capillary microfluidic channels.

[0099] Metallic nanostructures can excite surface plasmon resonance (LSPR), generating strong electromagnetic fields at the nanoscale and significantly enhancing the interaction between terahertz waves and biomolecules. Periodic plasmon structures can guide terahertz waves to propagate along specific paths, prolonging the interaction time with biomolecules.

[0100] In this invention, the width of the microfluidic channel is on the order of micrometers and the depth is on the order of hundreds of nanometers. Due to the capillary action of the liquid, the liquid can fill the microfluidic channel on its own without the action of an external driving force (such as a driving pump).

[0101] The terahertz metamaterial sensor is used to measure solutions and suspensions, and can be used for biosensing such as protein solutions, DNA solutions and other biological macromolecule solutions and virus solutions; it can also be used to measure non-biological solutions of different concentrations such as saline and alcohol solutions of different concentrations.

[0102] The second objective of this invention is to provide an application of a driverless terahertz metamaterial sensor based on capillary microchannels for micro-solution sensing in the terahertz band.

[0103] The terahertz band micro-solution sensing is used for biosensing and chemical sensing.

[0104] The biosensing includes the detection of biomacromolecules in protein solutions, DNA solutions, and virus solutions;

[0105] The chemical sensing includes the detection of non-biological solutions containing saline and alcohol concentrations.

[0106] In one embodiment of the present invention, during use, the solution inlet channel of the undriven terahertz metamaterial sensor is placed vertically upward, and the terahertz wave is incident perpendicularly to the plane where the metal unit array structure 2 is located. The incident sequence of the terahertz wave is first through the microcavity structure, then incident to the metamaterial layer, and finally exit from the sensor.

[0107] When the driverless terahertz metamaterial sensor of the present invention is in use, the solution wets the metamaterial layer and the microcavity structure. Under the action of atmospheric pressure and van der Waals force, the metamaterial layer and the microcavity structure can bind tightly together on their own. The microchannels naturally formed by the metamaterial layer are sealed by the microcavity, and finally a capillary structure is formed, which can absorb the solution on its own and ensure that the solution does not leak out.

[0108] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A driverless terahertz metamaterial sensor based on capillary microchannels, characterized in that, include: The metamaterial layers and microcavity structures are connected sequentially from top to bottom along the vertical direction; The connection between the metamaterial layer and the microcavity structure is detachable, allowing for reuse. The metamaterial layer includes a metal unit array structure (2), a capillary microfluidic channel (4), and a first substrate (1); the capillary microfluidic channel (4) is a channel isolated by the metal unit array structure (2) in the metamaterial layer; The capillary microfluidic channel can utilize the capillary phenomenon of liquid to allow the liquid to fill the microfluidic channel on its own, realizing the flow of liquid without driving force. The microcavity structure includes a first microfluidic channel (5), a second microfluidic channel (8), a solution inlet channel (6), and a solution outlet channel (7). The first microfluidic channel (5) and the second microfluidic channel (8) are respectively connected to the top and bottom of the metal unit array structure, and are used to connect multiple unit capillary microfluidic channels; The solution inlet channel (6) is connected to the first microfluidic channel (5) and adopts a stepped structure to maximize the guidance of liquid into the microfluidic channel; The solution outlet channel (7) is connected to the second microfluidic channel (8) to ensure that the microfluidic channel is connected to the air, which is a necessary condition for capillary self-absorption. The metal unit array structure includes multiple metal units (3), which are periodically arranged on the first substrate to form capillary microfluidic channels (4). The metal unit (3) includes a metal frame one (3-1), a metal frame two (3-2), and a unit capillary microfluidic channel (3-3). The first metal frame and the second metal frame are centrally symmetrical, forming a unit capillary microfluidic channel (3-3) in the middle. The second microfluidic channel includes channel one (8-1) and channel two (8-2); Channel 1 (8-1) is vertically connected to Channel 2 (8-2), and Channel 2 is also connected to Solution Outlet Channel (7). Solution Outlet Channel (7) is arranged parallel to Channel 1 (8-1). The solution outlet channel (7) is set in a horizontal direction; Channel 1 (8-1) connects multiple unit capillary microfluidic channels at the bottom of the metal unit array structure; Embedding nanoantennas or plasmonic structures within capillary microfluidic channels.

2. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, Each metal unit (3) is evenly distributed along the horizontal and vertical directions. In the vertical direction, the capillary microfluidic channels of each unit are aligned and connected to form a multi-column metal unit structure. The multi-column metal unit structure is arranged in an equal row-spaced column to form a metal unit array structure.

3. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The outer contours of the first metal frame (3-1) and the second metal frame (3-2) are rectangular; The inner contours of the first metal frame (3-1) and the second metal frame (3-2) are regular geometric shapes composed of horizontal and vertical straight lines.

4. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The first microfluidic channel (5) is vertically connected to the solution inlet channel (6), which is arranged in a vertical direction; The first microfluidic channel (5) connects multiple unit capillary microfluidic channels at the top of the metal unit array structure.

5. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The nanoantenna is a dipole antenna or a metamaterial structure; The dipole antenna is a metal nanorod or a V-shaped antenna, which can directionally enhance the radiation and reception of terahertz waves.

6. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The nanoantenna is a metamaterial structure.

7. The undriven terahertz metamaterial sensor based on capillary microchannels according to claim 1, characterized in that, The material of the metal unit (3) is metallic gold.

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