A terahertz detection device and a detection method

Abstract

The application provides a terahertz detection device and a detection method. The application can receive a terahertz signal to realize resonance through a microstrip resonant unit on a chip. A to-be-detected solution placed in a rectangular waveguide through a side wall through hole disturbs the resonant frequency of the microstrip resonant unit on the chip. Different concentrations of the to-be-detected solution change the spatial electromagnetic field of the resonant region, and the resonant frequency of the microstrip resonant unit on the chip is different under different spatial electromagnetic fields. The embodiment of the application can determine the concentration of the to-be-detected solution based on the influence of the concentration of the to-be-detected solution on the resonant frequency. Compared with the existing resonant cavity detection method, on the one hand, the resonant frequency of the microstrip resonant unit on the chip is not limited by the size of the resonant unit, and can be applied to large-size solution concentration detection while improving the working frequency. On the other hand, the resonant frequency of the microstrip resonant unit on the chip is improved, which can improve the detection working frequency and the detection sensitivity of the solution concentration detection.

Description

Technical Field

[0001] This invention relates to the field of terahertz technology, and in particular to a terahertz detection device and detection method. Background Technology

[0002] Terahertz (THz) waves are electromagnetic waves with frequencies ranging from 0.1 to 10 THz (wavelengths from 3000 to 30 μm). They overlap with millimeter waves in the long-wavelength range and with infrared light in the short-wavelength range. The terahertz wave band can cover the characteristic spectra of substances such as semiconductors, plasmas, organic matter, and biological macromolecules, and can be widely used in the detection of various materials.

[0003] Existing material detection methods involve placing the sample inside a resonant cavity for testing. Higher operating frequencies result in higher detection sensitivity. However, higher operating frequencies require smaller resonant cavity sizes, which are unsuitable for detecting large materials, such as solution concentrations. Consequently, existing methods for detecting solution concentrations are limited by the resonant cavity size, resulting in low operating frequencies and low detection sensitivity. Summary of the Invention

[0004] This invention provides a terahertz detection device and method to solve the problems of low operating frequency and low detection sensitivity in existing detection methods when detecting solution concentration.

[0005] In a first aspect, embodiments of the present invention provide a terahertz detection device, comprising: a rectangular waveguide, and a terahertz chip disposed inside the rectangular waveguide. The central portion of the terahertz chip is an on-chip microstrip resonant unit. A through-hole is provided on the sidewall of the rectangular waveguide at a position corresponding to the on-chip microstrip resonant unit. When detecting the concentration of a solution to be tested, a test tube containing the solution to be tested passes through the through-hole, extends into the cavity of the rectangular waveguide, and is placed in the resonant region where the on-chip microstrip resonant unit is located. The solution to be tested alters the spatial electromagnetic field of the resonant region, causing a change in the resonant frequency at the output of the terahertz detection device. The change in resonant frequency corresponds one-to-one with the concentration of the solution to be tested.

[0006] In one possible implementation, the terahertz chip further includes an input microstrip line and an output microstrip line connecting the on-chip microstrip resonant unit. The input microstrip line receives multi-frequency terahertz signals through the input terminal of the rectangular waveguide. The on-chip microstrip resonant unit generates a resonant signal disturbed by the solution under test under the excitation of the terahertz signals. The output microstrip line outputs the resonant signal to an external detection device through the output terminal of the rectangular waveguide. The external detection device measures the resonant frequency of the resonant signal and determines the concentration of the solution under test based on a preset correspondence between the resonant frequency and the solution concentration.

[0007] In one possible implementation, the on-chip microstrip resonant unit includes a ring microstrip resonator, an I-shaped microstrip resonator, or a Y-shaped microstrip resonator.

[0008] In one possible implementation, the via is disposed on the sidewall of the rectangular waveguide facing the front of the terahertz chip, and directly above the on-chip microstrip resonator.

[0009] In one possible implementation, the via is also disposed on the sidewall of the rectangular waveguide facing the back of the terahertz chip, and directly below the on-chip microstrip resonator.

[0010] In one possible implementation, the output of the rectangular waveguide is also connected to a power meter. The power meter detects the power at each frequency of the resonant signal and outputs the power at each frequency of the resonant signal to an external detection device.

[0011] In one possible implementation, the external detection device determines the frequency at which the insertion loss of the resonant signal is at its maximum value based on the power output of the power meter at each frequency point.

[0012] Secondly, embodiments of the present invention provide a terahertz detection method, applied to any of the terahertz detection devices described above, characterized in that the method includes: acquiring a first power set of the terahertz signal at each frequency point at the input terminal of the on-chip microstrip resonant unit; acquiring a second power set of the resonant signal at each frequency point at the output terminal of the on-chip microstrip resonant unit; obtaining the insertion loss at each frequency point based on the first power set of the input terahertz signal at each frequency point and the second power set of the output resonant signal at each frequency point; determining the resonant frequency based on the insertion loss at each frequency point; and determining the concentration of the solution to be tested based on a preset correspondence between the resonant frequency and the solution concentration.

[0013] In one possible implementation, determining the resonant frequency based on the insertion loss at each frequency point includes: obtaining the frequency corresponding to the frequency point where the insertion loss is maximum based on the insertion loss at each frequency point; and determining the frequency corresponding to the frequency point where the insertion loss is maximum as the resonant frequency.

[0014] In one possible implementation, before determining the concentration of the test solution based on the preset correspondence between the resonant frequency and the solution concentration, the method further includes: Step 1: Obtaining preset concentrations of multiple preset test solutions and designating any one of the preset test solutions as the target solution. Step 2: Obtaining the second power set of each frequency point of the resonant signal corresponding to the target solution. The resonant signal is the resonant signal output by the on-chip microstrip resonant unit under the excitation of the terahertz signal, which is disturbed by the target solution. Step 3: Obtaining the insertion loss of each frequency point corresponding to the target solution based on the first power set of each frequency point of the terahertz signal and the second power set of each frequency point of the resonant signal disturbed by the target solution. Step 4: Determining the resonant frequency corresponding to the target solution based on the insertion loss of each frequency point corresponding to the target solution. Step 5: Using any undetected preset test solution as the target solution, repeating steps 2, 3, and 4 to obtain the preset correspondence between the resonant frequency and the solution concentration.

[0015] This invention provides a terahertz detection device and method. The invention achieves resonance by receiving terahertz signals through an on-chip microstrip resonant unit of a terahertz chip. A test solution placed inside a rectangular waveguide through a sidewall aperture disturbs the resonant frequency of the on-chip microstrip resonant unit. Different concentrations of the test solution alter the spatial electromagnetic field of the resonant region, resulting in different resonant frequencies of the on-chip microstrip resonant unit under different spatial electromagnetic fields. This invention allows the concentration of the test solution to be determined based on the magnitude of its influence on the resonant frequency. Compared to existing resonant cavity detection methods, on the one hand, the increase in the resonant frequency of the on-chip microstrip resonant unit is not limited by the size of the resonant unit, allowing for the detection of large-scale solutions while simultaneously increasing the operating frequency. On the other hand, increasing the resonant frequency of the on-chip microstrip resonant unit can improve the detection operating frequency and enhance the detection sensitivity of the solution concentration. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0017] Figure 1 This is a three-dimensional perspective structural diagram of the terahertz detection device provided in an embodiment of the present invention;

[0018] Figure 2 This is a top view of the terahertz chip provided in an embodiment of the present invention;

[0019] Figure 3This is a schematic cross-sectional view of the terahertz detection device provided in an embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the cross-sectional structure of another terahertz detection device provided in an embodiment of the present invention;

[0021] Figure 5 This is a flowchart illustrating the implementation of the terahertz detection method provided in this embodiment of the invention.

[0022] Figure 6 This is a schematic diagram of the terahertz detection system provided in an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram showing the change of insertion loss with frequency for solutions of different concentrations provided in this embodiment of the invention;

[0024] Figure 8 This is a schematic diagram illustrating the relationship between different solution concentrations and resonant frequencies provided in an embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0026] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0027] The implementation of the present invention will be described in detail below with reference to the accompanying drawings:

[0028] This invention provides a terahertz detection device. By setting up a rectangular waveguide and a terahertz chip, the solution concentration is determined based on the influence of the concentration of the sample to be measured inside the rectangular waveguide on the resonant frequency. Therefore, it can be applied to the detection of large-scale solutions while increasing the operating frequency, thereby improving both the detection frequency and the detection sensitivity.

[0029] Figure 1 This is a three-dimensional perspective structural diagram of the terahertz detection device provided in an embodiment of the present invention. Figure 1 In the image, the terahertz chip and the solution under test are shown through the outermost rectangular waveguide. Figure 2 This is a top view of the terahertz chip provided in an embodiment of the present invention. Figure 2 It is by Figure 1 A top-down view of the terahertz chip. Figure 3 This is a schematic diagram of the cross-sectional structure of the terahertz detection device provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the cross-sectional structure of the terahertz detection device at the through-hole location, wherein the cross-section is perpendicular to the surface of the terahertz chip.

[0030] Reference Figure 1 , Figure 2 and Figure 3 The terahertz detection device includes a rectangular waveguide and a terahertz chip disposed inside the rectangular waveguide. The central portion of the terahertz chip is an on-chip microstrip resonator. Through-holes are provided on the sidewall of the rectangular waveguide at positions corresponding to the on-chip microstrip resonator. When detecting the concentration of the solution to be tested, a test tube containing the solution is inserted through the through-hole into the cavity of the rectangular waveguide and placed in the resonant region of the on-chip microstrip resonator. The solution to be tested alters the spatial electromagnetic field of the resonant region, causing a change in the resonant frequency at the output of the terahertz detection device. The change in resonant frequency corresponds one-to-one with the concentration of the solution to be tested.

[0031] In some embodiments, a rectangular waveguide is a metallic waveguide with a rectangular cross-section of its internal waveguide cavity. Exemplarily, a rectangular waveguide includes open input and output ports. For example, the input and output ports of a rectangular waveguide are standard rectangular waveguide ports.

[0032] In some embodiments, the middle part of the terahertz chip is an on-chip microstrip resonant unit.

[0033] For example, a terahertz chip includes a substrate and an on-chip microstrip resonant unit disposed on the substrate. For instance, an input microstrip line, an on-chip microstrip resonant unit, and an output microstrip line are disposed on the substrate in sequence, with the on-chip microstrip resonant unit disposed in the middle.

[0034] Furthermore, exemplaryly, the substrate material includes silicon, gallium nitride, gallium arsenide, indium phosphide, quartz, or aluminum nitride. Exemplarily, the substrate is an insulating substrate or a semi-insulating substrate.

[0035] For example, an on-chip microstrip resonant unit is a resonant structure composed of microstrip lines disposed on a substrate. For instance, refer to... Figure 2 The on-chip microstrip resonant unit can be a figure-eight microstrip resonator. For example, the on-chip microstrip resonant unit can also be a ring microstrip resonator, an I-shaped microstrip resonator, or a Y-shaped microstrip resonator.

[0036] In some embodiments, the terahertz chip is disposed inside a rectangular waveguide.

[0037] For example, the input microstrip line of the terahertz chip faces the input end of the rectangular waveguide, and the output microstrip line of the terahertz chip faces the output end of the rectangular waveguide.

[0038] In some embodiments, a through hole is provided on the sidewall of the rectangular waveguide at a position corresponding to the on-chip microstrip resonant unit.

[0039] For example, a rectangular waveguide includes four sidewalls, and a through-hole is provided on any one of the sidewalls. The through-hole penetrates through the sidewall of the rectangular waveguide, connecting the interior and exterior of the rectangular waveguide.

[0040] For example, the through-hole points in the direction of the rectangular waveguide toward the position corresponding to the on-chip microstrip resonator.

[0041] It should be noted that, in this invention, the aforementioned through-hole is used to allow a test tube containing the test solution to pass through the through-hole, extend into the cavity of the rectangular waveguide, and be placed in the resonant region of the on-chip microstrip resonant unit during concentration detection. Thus, on the one hand, the test tube containing the test solution can be fixed to the rectangular waveguide through the through-hole, and the rectangular waveguide provides a supporting function. On the other hand, the test solution, placed inside the rectangular waveguide through the through-hole, also shields against external electromagnetic interference, ensuring that only the test solution alters the spatial electromagnetic field of the resonant region.

[0042] The concentration detection process is explained in detail below: The test solution is placed in a test tube. During concentration detection, the test tube containing the test solution passes through a through-hole and extends into the cavity of the rectangular waveguide, placing it within the resonant region of the on-chip microstrip resonator. When the test solution approaches the resonant region of the on-chip microstrip resonator, it alters the spatial electromagnetic field of the resonant region, thereby changing the resonant frequency of the on-chip microstrip resonator and ultimately altering the resonant frequency at the output of the terahertz detection device. The change in the resonant frequency of the on-chip microstrip resonator corresponds one-to-one with the concentration of the test solution. Therefore, the concentration of the test solution can be determined based on the change in the resonant frequency before and after placing the test solution. Alternatively, the concentration can also be determined based on the resonant frequency after placing the test solution.

[0043] It should be noted that differences in the distance, orientation, and capacity between the solution under test and the on-chip microstrip resonant unit will affect the resonant frequency. Therefore, these conditions must be kept constant during testing. For example, a limiting device can be installed on the rectangular waveguide to restrict the length and orientation of the test tube extending into the rectangular waveguide. Alternatively, test tubes of the same specification can be used to ensure that the volume of solution extending into the rectangular waveguide is the same.

[0044] In addition, the material of the test tube itself can also have a significant impact on the resonant frequency. For example, the test tube material can be a low dielectric constant material to reduce the influence of the test tube material itself on the resonant frequency. For instance, the test tube material can be quartz or Teflon.

[0045] This invention utilizes an on-chip microstrip resonant unit of a terahertz chip to receive terahertz signals and achieve resonance. The test solution, placed inside a rectangular waveguide through a sidewall via, perturbs the resonant frequency of the on-chip microstrip resonant unit. Different concentrations of the test solution alter the spatial electromagnetic field of the resonant region, resulting in different resonant frequencies for the on-chip microstrip resonant unit under different spatial electromagnetic fields. This invention allows the determination of the test solution concentration based on the magnitude of its influence on the resonant frequency. Compared to existing resonant cavity detection methods, this invention offers several advantages. First, the increased resonant frequency of the on-chip microstrip resonant unit is not limited by the unit's size, allowing for applications in large-scale solution concentration detection while simultaneously increasing the operating frequency. Second, the increased resonant frequency of the on-chip microstrip resonant unit enhances both the detection operating frequency and the sensitivity of solution concentration detection.

[0046] It should be noted that the on-chip microstrip resonant unit has a higher intrinsic resonant frequency than the resonant cavity, enabling resonance in the terahertz frequency band. Furthermore, while the size of the on-chip microstrip resonant unit changes when the resonant frequency is further increased, the size of the rectangular waveguide cavity does not need to change. In the resonant cavity configuration, increasing the resonant frequency leads to a continuous decrease in the cavity size, eventually making it impossible to place the solution to be tested inside the cavity, thus hindering high-frequency solution concentration detection. Therefore, increasing the resonant frequency of the on-chip microstrip resonant unit is not limited by the size of the resonant unit, allowing for applications in large-scale solution concentration detection while simultaneously increasing the operating frequency. Furthermore, increasing the resonant frequency of the on-chip microstrip resonant unit can increase the detection operating frequency and improve the detection sensitivity of solution concentration.

[0047] Reference Figure 2 , Figure 2 The top view of the terahertz chip is shown. Below is based on... Figure 2 Note: In one possible implementation, the terahertz chip further includes an input microstrip line and an output microstrip line connecting the on-chip microstrip resonant unit. The input microstrip line receives multi-frequency terahertz signals through the input terminal of a rectangular waveguide. The on-chip microstrip resonant unit generates a resonant signal disturbed by the solution under test under the excitation of the terahertz signal. The output microstrip line outputs the resonant signal to an external detection device through the output terminal of the rectangular waveguide. The external detection device measures the resonant frequency of the resonant signal and determines the concentration of the solution under test based on a preset correspondence between the resonant frequency and the solution concentration.

[0048] In some embodiments, the terahertz chip includes an input microstrip line, an on-chip microstrip resonant unit, and an output microstrip line connected in sequence.

[0049] In some embodiments, the input microstrip line receives multi-frequency terahertz signals through the input end of a rectangular waveguide.

[0050] For example, the input of a rectangular waveguide is connected to a terahertz power source to receive terahertz signals at multiple frequencies. For instance, the input of the rectangular waveguide is connected to a terahertz power source with frequency sweep functionality. It should be noted that the frequency range of the terahertz signal includes the resonant frequency of the on-chip microstrip resonator, thus enabling the on-chip microstrip resonator to resonate under the excitation of the terahertz signal.

[0051] In some embodiments, the on-chip microstrip resonant unit generates a resonant signal under the excitation of a terahertz signal.

[0052] Furthermore, during the concentration detection of the test solution, a test tube containing the test solution is inserted through a through-hole into the cavity of the rectangular waveguide and placed in the resonant region of the on-chip microstrip resonator. The test solution disturbs the resonance of the on-chip microstrip resonator, generating a resonant signal disturbed by the test solution. That is, the on-chip microstrip resonator outputs a resonant signal disturbed by the test solution under the excitation of the terahertz signal.

[0053] Furthermore, in some embodiments, the output microstrip line outputs the resonant signal to an external detection device through the output end of a rectangular waveguide, so as to facilitate the next step of resonant frequency detection and solution concentration determination.

[0054] In some embodiments, rectangular waveguide transmission TE 10 The terahertz chip transmits TEM wave signals.

[0055] Specifically, the input end of the rectangular waveguide receives TE. 10 The terahertz signal is converted into a TEM wave at the junction of the rectangular waveguide input and the input microstrip line of the terahertz chip. The input microstrip line then transmits the TEM wave terahertz signal to the on-chip microstrip resonant unit. Excited by the TEM wave terahertz signal, the on-chip microstrip resonant unit generates a TEM wave resonant signal and outputs it through the output microstrip line. The TEM wave resonant signal is converted into a TEM wave terahertz signal at the junction of the output microstrip line and the output of the rectangular waveguide. 10 The resonant signal of the wave is generated and output to an external detection device.

[0056] Therefore, through the rectangular waveguide and the TE of the terahertz chip 10The TEM wave conversion avoids direct transmission of TEM wave signals, eliminates the need for probe connections between input and output microstrip lines, avoids the risk of damage from repeated probe connections, and prevents probe-induced damage to the microstrip lines, thus improving test reliability. Furthermore, the rectangular waveguide method for implementing terahertz signal input and output is simpler than the probe method.

[0057] In one possible implementation, a power meter is also connected to the output of the rectangular waveguide. The power meter detects the power at each frequency of the resonant signal and outputs the power at each frequency of the resonant signal to an external detection device.

[0058] In this embodiment of the invention, by detecting the power at each frequency point of the output resonant signal, the loss distribution of the resonant signal can be determined based on the difference between the input power and the output power of the rectangular waveguide, and thus the resonant frequency can be determined.

[0059] In one possible implementation, the external detection device determines the frequency at which the insertion loss of the resonant signal is at its maximum based on the power output of the power meter at each frequency.

[0060] In this embodiment of the invention, the frequency point at which the insertion loss of the resonant signal is at its maximum is determined as the resonant frequency of the resonant signal. Based on a preset correspondence between the resonant frequency and the solution concentration, the concentration of the solution to be tested can be determined, thereby realizing the measurement of the solution concentration.

[0061] In one possible implementation, the on-chip microstrip resonant unit includes a ring microstrip resonator, an I-shaped microstrip resonator, or a Y-shaped microstrip resonator.

[0062] In one possible implementation, the distance between the on-chip microstrip resonator and the test tube ranges from 10 to 100 micrometers.

[0063] Reference Figure 3 In one possible implementation, the via is located on the sidewall of the rectangular waveguide facing the front of the terahertz chip, and directly above the on-chip microstrip resonator.

[0064] Figure 4 This is a schematic cross-sectional view of another terahertz detection device provided in an embodiment of the present invention. (Refer to...) Figure 4 In one possible implementation, the via is also located on the sidewall of the rectangular waveguide facing the back of the terahertz chip, and directly below the on-chip microstrip resonator.

[0065] In this embodiment of the invention, the accuracy of the detection results can be improved by placing the test solution directly above and below the on-chip microstrip resonant unit.

[0066] Figure 5 This is a flowchart illustrating the implementation of the terahertz detection method provided in this embodiment of the invention. (Refer to...) Figure 5This invention provides a terahertz detection method, applicable to any of the aforementioned terahertz detection devices, characterized in that the method includes:

[0067] In step 501, the first power set of the terahertz signal at each frequency point at the input terminal of the on-chip microstrip resonant unit is obtained.

[0068] For example, the signal received at the input of the terahertz detection device is a multi-frequency terahertz signal. Accordingly, the power of the multi-frequency terahertz signal at each frequency is obtained to obtain the first power set of the terahertz signal at each frequency of the input of the on-chip microstrip resonant unit.

[0069] In step 502, the second power set of the resonant signal at each frequency point of the output terminal of the on-chip microstrip resonant unit is obtained.

[0070] For example, prior to step 502, a test tube containing the solution to be tested is inserted through a through-hole into the cavity of a rectangular waveguide and placed in the resonant region of the on-chip microstrip resonant unit. The solution to be tested then alters the spatial electromagnetic field of the resonant region, causing a change in the resonant frequency at the output of the terahertz detection device.

[0071] For example, the resonant signal is the resonant signal output by the on-chip microstrip resonant unit under the excitation of the terahertz signal, which is disturbed by the solution under test.

[0072] For example, the signal received at the input of the terahertz detection device is a multi-frequency terahertz signal, and correspondingly, the output resonant signal is a multi-frequency resonant signal.

[0073] In some embodiments, the power of the resonant signal at each frequency point is detected by a power meter to obtain a second power set of the resonant signal at each frequency point of the on-chip microstrip resonant unit output terminal.

[0074] In step 503, the insertion loss at each frequency point is obtained based on the first power set of each frequency point of the input terahertz signal and the second power set of each frequency point of the output resonant signal.

[0075] In some embodiments, the insertion loss of each frequency point is obtained by subtracting the corresponding power value in the first power set from the corresponding power value in the second power set.

[0076] For example, insertion loss here refers to the magnitude of the loss of the terahertz signal after passing through the terahertz detection device.

[0077] In step 504, the resonant frequency is determined based on the insertion loss at each frequency point.

[0078] In one possible implementation, determining the resonant frequency based on the insertion loss at each frequency point includes: obtaining the frequency corresponding to the frequency point where the insertion loss is maximum based on the insertion loss at each frequency point; and determining the frequency point corresponding to the frequency point where the insertion loss is maximum as the resonant frequency.

[0079] It should be noted that terahertz signals resonate in the on-chip microstrip resonant unit, and power is lost during resonance. Therefore, the frequency with the greatest insertion loss corresponds to the frequency with the strongest resonance, i.e., the resonant frequency.

[0080] In step 505, the concentration of the solution to be tested is determined based on the preset correspondence between the resonant frequency and the solution concentration.

[0081] In step 504, the resonant frequency corresponding to the solution to be tested is obtained. Then, in step 505, based on the preset correspondence between the resonant frequency and the solution concentration, the solution concentration corresponding to the resonant frequency of the solution to be tested, i.e., the concentration of the solution to be tested, can be determined.

[0082] It should be noted that, based on the aforementioned terahertz detection device, by testing the resonant frequencies corresponding to multiple solutions of known concentrations, a preset correspondence between the resonant frequency and the solution concentration can be obtained. This will be explained in detail below:

[0083] In one possible implementation, before determining the concentration of the solution to be tested based on a preset correspondence between the resonant frequency and the solution concentration, the following steps are also included:

[0084] Step 1: Obtain the preset concentrations of multiple preset test solutions, and use any one of the preset test solutions as the target solution.

[0085] Step 2: Obtain the second power set of each frequency point of the resonant signal corresponding to the target solution. The resonant signal is the resonant signal output by the on-chip microstrip resonant unit under terahertz signal excitation, which is disturbed by the target solution.

[0086] Step 3: Based on the first power set of each frequency point of the terahertz signal and the second power set of each frequency point of the resonant signal disturbed by the target solution, obtain the insertion loss of each frequency point corresponding to the target solution.

[0087] Step 4: Determine the resonant frequency of the target solution based on the insertion loss at each frequency point.

[0088] Step 5: Take any untested preset test solution as the target solution, and repeat steps 2, 3 and 4 to obtain the preset correspondence between the resonant frequency and the solution concentration.

[0089] The following specific embodiment illustrates the process of detecting solution concentration using the terahertz-based detection device provided by the present invention.

[0090] Figure 6 This is a schematic diagram of the terahertz detection system provided in an embodiment of the present invention. (Refer to...) Figure 6 The input of the terahertz detection device is connected to a terahertz power source, and the output is connected to a terahertz power meter.

[0091] 1. The terahertz power meter measures the output power of the terahertz power source at each frequency point within its test frequency range. The terahertz power source has a frequency sweep function, capable of outputting a terahertz signal across a frequency range including the sensor's resonant frequency, with a sweep frequency step size of up to 0.1MHz. The output power of the terahertz power source is the input power of the terahertz detection device, denoted as P. in The unit is dBm.

[0092] 2. Pre-prepared solutions of different concentrations were poured into test tubes in different batches, and the output power of the terahertz detector was measured and recorded as P. out The unit is dBm.

[0093] 3. Data processing was performed on the test parameters of solutions of different concentrations to obtain the transmission loss of each concentration solution at each frequency point, recorded as LOSS, in dB. The calculation formula is as follows:

[0094] LOSS(dB)=P out (dBm)-P in (dBm).

[0095] Based on the transmission loss of each concentration solution at each frequency point, the frequency corresponding to the maximum transmission loss is determined as the resonant frequency of that concentration solution.

[0096] 4. Process the solution concentration and resonant frequency data obtained in step 3 to obtain the linear relationship between the two.

[0097] 5. Test the sensor output power parameters of the solution with unknown concentration. Obtain the resonant frequency based on the data processing in step 3. Then, based on the linear relationship between the solution concentration and the resonant frequency obtained in step 4, the solution concentration can be measured.

[0098] The following example uses NaCl solution. Figure 7 This is a schematic diagram illustrating the change in insertion loss of NaCl solutions of different concentrations as a function of frequency, provided in an embodiment of the present invention. The horizontal axis represents the frequency of the resonant signal in GHz, and the vertical axis represents the insertion loss in dB. The five curves in the figure represent the change in insertion loss of NaCl solutions of different concentrations as a function of frequency. The frequency corresponding to the maximum insertion loss is the resonant frequency of that concentration of solution.

[0099] Figure 8This is a schematic diagram illustrating the relationship between different solution concentrations and resonant frequencies, provided in an embodiment of the present invention. The horizontal axis represents the solution concentration, and the vertical axis represents the resonant frequency. Figure 8 The relationship between NaCl solution concentration and resonant frequency is shown.

[0100] When testing the solution concentration, the output power of an unknown concentration of NaCl solution is measured to obtain the resonant frequency. The concentration of the NaCl solution can then be determined from the resonant frequency.

[0101] It should be noted that when the sample being tested is a solution, the different dielectric constants and tangents of different solution concentrations will have different effects on the electromagnetic field above and below the resonant unit, resulting in different resonant frequencies. The corresponding solution concentration can be measured using these different resonant frequencies. Because the terahertz band has high frequencies and short wavelengths, it is possible to test even smaller dielectric constant gradients.

[0102] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A terahertz detection device, characterized in that, include: A rectangular waveguide, and a terahertz chip disposed inside the rectangular waveguide; The terahertz chip includes a substrate and an on-chip microstrip resonant unit disposed on the substrate; the middle part of the terahertz chip is the on-chip microstrip resonant unit; the on-chip microstrip resonant unit is a resonant structure composed of microstrip lines disposed on the substrate; a through hole is provided on the sidewall of the rectangular waveguide at a position corresponding to the on-chip microstrip resonant unit; The via is disposed on the sidewall of the rectangular waveguide facing the front of the terahertz chip, and is disposed directly above the on-chip microstrip resonant unit; When detecting the concentration of the solution to be tested, the test tube containing the solution to be tested passes through the through hole, extends into the cavity of the rectangular waveguide, and is placed in the resonant region of the on-chip microstrip resonant unit. The test solution alters the spatial electromagnetic field of the resonant region, thereby changing the resonant frequency at the output of the terahertz detection device; wherein the change in resonant frequency corresponds one-to-one with the concentration of the test solution.

2. The terahertz detection device as described in claim 1, characterized in that, The terahertz chip further includes: an input microstrip line and an output microstrip line connecting the on-chip microstrip resonant unit; The input microstrip line receives multi-frequency terahertz signals through the input end of the rectangular waveguide; The on-chip microstrip resonant unit generates a resonant signal that is disturbed by the solution under test under the excitation of the terahertz signal; The output microstrip line outputs the resonant signal to an external detection device through the output end of the rectangular waveguide; the external detection device measures the resonant frequency of the resonant signal and determines the concentration of the solution to be tested based on a preset correspondence between the resonant frequency and the solution concentration.

3. The terahertz detection device as described in claim 1, characterized in that, The on-chip microstrip resonant unit includes a ring microstrip resonator, an I-shaped microstrip resonator, or a Y-shaped microstrip resonator.

4. The terahertz detection device as described in claim 1, characterized in that, The via is also disposed on the sidewall of the rectangular waveguide facing the back of the terahertz chip, and directly below the on-chip microstrip resonator.

5. The terahertz detection device as described in claim 2, characterized in that, The output end of the rectangular waveguide is also connected to a power meter; The power meter detects the power at each frequency point of the resonant signal and outputs the power at each frequency point of the resonant signal to an external detection device.

6. The terahertz detection device as described in claim 5, characterized in that, The external detection device determines the frequency at which the insertion loss of the resonant signal is at its maximum value based on the power output of the power meter at each frequency point.

7. A terahertz detection method, applied to the terahertz detection device according to any one of claims 1-6, characterized in that, The method includes: Obtain the first power set of the terahertz signal at each frequency point at the input terminal of the on-chip microstrip resonant unit; Obtain the second power set of the resonant signal at each frequency point of the output terminal of the on-chip microstrip resonant unit; Based on the first power set of each frequency point of the input terahertz signal and the second power set of each frequency point of the output resonant signal, the insertion loss at each frequency point is obtained; Based on the insertion loss at each frequency point, the resonant frequency is determined; Based on the preset correspondence between the resonant frequency and the solution concentration, the concentration of the solution to be tested is determined.

8. The terahertz detection method as described in claim 7, characterized in that, Determining the resonant frequency based on the insertion loss at each frequency point includes: Based on the insertion loss at each frequency point, the frequency corresponding to the frequency point with the maximum insertion loss is obtained; The frequency at which the insertion loss is at its maximum is determined as the resonant frequency.

9. The terahertz detection method as described in claim 7, characterized in that, Before determining the concentration of the solution to be tested based on the preset correspondence between the resonant frequency and the solution concentration, the method further includes: Step 1: Obtain the preset concentrations of multiple preset test solutions, and use any one of the preset test solutions as the target solution; Step 2: Obtain the second power set of each frequency point of the resonant signal corresponding to the target solution; the resonant signal is the resonant signal output by the on-chip microstrip resonant unit under the excitation of the terahertz signal and disturbed by the target solution; Step 3: Based on the first power set of each frequency point of the terahertz signal and the second power set of each frequency point of the resonant signal disturbed by the target solution, obtain the insertion loss of each frequency point corresponding to the target solution; Step 4: Determine the resonant frequency of the target solution based on the insertion loss at each frequency point. Step 5: Take any untested preset test solution as the target solution, and repeat steps 2, 3 and 4 to obtain the preset correspondence between the resonant frequency and the solution concentration.

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