Portable terahertz calibration module based on adjustable double-path structure

Abstract

The invention discloses a portable terahertz calibration module based on an adjustable double-path structure, and the module employs a double-channel geometric structure composed of an I-shaped half-open cavity fixed short path and a U-like half-open cavity adjustable long path, and cooperates with a sliding mechanism and a pluggable module. And high-precision calibration of the dynamic range, the amplitude linearity and the sensitivity of the path time delay of the terahertz system to be tested can be realized within the frequency band of 0.1-10 THz. And reflection, absorption and semi-absorption modes can be realized through second-level switching of the reflecting mirror of the pluggable module and the wave-absorbing material, and a complex channel state can be simulated without re-aligning an optical path. Besides, an ultrathin wave-absorbing material adopted by the module ensures undisturbed compatibility of an optical path and provides a uniform reference with traceable quantity values, so that the basic bottleneck in terahertz channel modeling and equipment specification formulation is effectively broken through, and reliable metering support is provided for field deployment and large-scale application of 6G terahertz communication.

Description

Technical Field

[0001] This invention relates to the field of terahertz (THz) communication metrology and channel modeling technology, and in particular to a portable terahertz calibration module based on an adjustable dual-path structure. Background Technology

[0002] In the past two years, channel measurement platforms centered on terahertz time-domain spectroscopy and vector network analyzers have proliferated. However, these platforms differ significantly in key parameters such as frequency band, bandwidth, power, antenna configuration, dynamic range, and time base stability. This makes it impossible to cross-reference multipath delay spectra, path gain, loss curves, and noise floor measurements obtained in the same scenario, resulting in low reliability of weak paths and difficulty in unifying models. The calibration standards used for 5G millimeter waves are completely ineffective against the ultra-large bandwidth of THz, picosecond pulses, and strong dispersion characteristics. Therefore, establishing a unified terahertz measurement and calibration benchmark for 6G has become a fundamental bottleneck that urgently needs to be overcome in developing channel models and equipment specifications. While existing universities and institutions have attempted to construct artificial multipath environments in laboratories using mechanical slides and rotating metal plates, these methods can only generate fixed-reflection metal channels, failing to independently control path gain or reproduce the scattering and absorption effects of the real world.

[0003] Therefore, there is an urgent need for an adjustable dual-path, portable terahertz calibration module to systematically evaluate the delay dynamic range, amplitude linearity, and spurious suppression capability of the device under test in the 0.1–10 THz frequency band, and to provide a traceable standard reference for the measurement values. This would enable cross-platform and cross-scenario comparison of multipath delay and path loss, and provide a unified benchmark for 6G terahertz channel models and equipment specifications. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a portable terahertz calibration module based on an adjustable dual-path structure, aiming to achieve cross-platform and cross-scenario unified calibration and measurement traceability of adjustable time delay and path gain across the entire frequency band of 0.1–10 THz.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0006] A portable terahertz calibration module based on an adjustable dual-path structure includes:

[0007] A dual-channel geometry structure, comprising an I-shaped semi-open cavity structure and a U-shaped semi-open cavity structure, wherein the I-shaped semi-open cavity structure forms a fixed short path and the U-shaped semi-open cavity structure forms a long path with adjustable length.

[0008] A sliding mechanism connects the I-shaped semi-open cavity structure and the U-shaped semi-open cavity structure, and is used to adjust the geometric length of the U-shaped semi-open cavity structure;

[0009] A pluggable module is located at multiple wall-side positions of the dual-channel geometry to switch between the reflector and the absorbing material, thereby enabling switching between reflection mode, absorption mode and semi-absorption mode.

[0010] The dual-channel geometry is made of ferrous metal, with the signal input terminal S1 on the left and the signal output terminal S2 on the right.

[0011] Furthermore, the pluggable module has 12 preset positions, specifically defined as follows:

[0012] The first position is located near the signal input terminal S1 within the I-shaped semi-open cavity structure;

[0013] The second position is located near the signal output end S2 within the I-shaped semi-open cavity structure, and is mirror-aligned with the first position.

[0014] The third position is located on the left side of the turning angle within the U-shaped semi-open cavity structure;

[0015] The fourth position is located on the right side of the turning angle within the U-shaped semi-open cavity structure, mirror-aligned with the third position;

[0016] The fifth position is located on the inner wall of the vertical path in the middle of the left side of the U-shaped semi-open cavity structure;

[0017] The sixth position is positioned opposite the fifth position and aligned with it.

[0018] The seventh position is located on the left inner wall of the top path of the U-shaped semi-open cavity structure;

[0019] The eighth position is set opposite the seventh position, and aligned with the seventh position;

[0020] The ninth and tenth positions are located on the right inner wall of the top path of the U-shaped semi-open cavity structure, mirroring and aligned with the seventh and eighth positions.

[0021] The eleventh and twelfth positions are located on the inner wall of the vertical path in the middle right side of the U-shaped semi-open cavity structure; they are mirror-aligned with the fifth and sixth positions.

[0022] Furthermore, when the first and second positions are reflectors, they are used to form a fixed short path in reflection mode.

[0023] Furthermore, when the third and fourth positions are reflectors, they are used to adjust the length of the long path in reflection mode via a sliding mechanism.

[0024] Furthermore, the absorbing material at the fifth to twelfth positions.

[0025] Furthermore, the absorbing material is an absorbing material of different thicknesses, used to adjust the path gain in absorption mode.

[0026] Furthermore, the pluggable module can be switched to a reflector or a absorbing material at any position to achieve a semi-absorption mode.

[0027] Furthermore, the portable terahertz calibration module is used to calibrate the time delay dynamic range, amplitude linearity, and sensitivity of a terahertz system within the 0.1–10 THz frequency band.

[0028] Furthermore, the time delay dynamic range calibration is achieved through the reflection mode, and the amplitude linearity and sensitivity calibration are achieved through the absorption mode and the semi-absorption mode.

[0029] Compared with the prior art, the advantages of the present invention are as follows:

[0030] The portable terahertz calibration module based on tunable dual-path proposed in this invention achieves a leap forward in amplitude linearity and sensitivity calibration across platforms and scenarios. It can directly serve the two mainstream systems of terahertz time-domain spectroscopy (TDS) and vector network analysis (VNA), providing traceable and reproducible hardware-level support for dynamic optimization and adaptive transmission of communication links. Its core advantages are reflected in:

[0031] (1) Rapid switching between multiple scenarios: The pluggable structure supports the second-level switching of three working modes: reflection, full absorption and half absorption. It can simulate complex channel states without re-aligning the optical path, significantly improving the efficiency of laboratory and field deployment and meeting the field testing requirements of plug and play.

[0032] (2) Uninterrupted compatibility of optical path: Using extremely thin absorbing material, there are no additional aberrations for parallel, divergent or vector beams. It can be seamlessly embedded into existing collimation, beam contraction or confocal optical path systems, avoiding secondary focusing and ensuring the continuity and consistency of the measurement process.

[0033] (3) Wide frequency band coverage: The device covers the 0.1-10 THz frequency band without wavelength selectivity, providing a unified calibration benchmark for terahertz time-domain spectroscopy and vector network analysis systems, breaking through the frequency band limitations of existing schemes;

[0034] (4) Measurement traceability and reliability improvement: Through the coordinated design of adjustable path and gradient absorbing material, high-precision calibration of time delay dynamic range, amplitude linearity and sensitivity is achieved, which significantly improves the reliability and consistency of calibration results and provides reproducible and traceable metrological support for channel modeling and equipment specification formulation of 6G terahertz communication.

[0035] In summary, this invention improves calibration accuracy to a three-dimensional collaborative level through miniaturization and modular design, fundamentally solving the problem of missing metrological benchmarks in the process of terahertz communication moving from the laboratory to industrialization, and laying a solid foundation for the large-scale application of terahertz technology in the fields of communication, imaging and sensing. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention 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.

[0037] Figure 1 This is a schematic diagram of the portable terahertz calibration module in Embodiment 1 of the present invention.

[0038] Figure 2 This is a schematic diagram of the structural combination of the portable terahertz calibration module in Embodiment 1 of the present invention.

[0039] Figure 3 This is a three-dimensional schematic diagram of the portable terahertz calibration module in Embodiment 1 of the present invention.

[0040] Figure 4 This is a flowchart illustrating the usage principle of the portable terahertz calibration module in Embodiment 2 of the present invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1

[0043] This invention proposes a portable terahertz calibration module based on an adjustable dual-path structure, as shown in the schematic diagram below. Figure 1 As shown, it consists of a dual-channel geometry with short and long paths, a sliding mechanism, and pluggable modules, such as... Figure 2 The dual-channel geometry consists of an I-shaped semi-open cavity structure 101 and a U-shaped semi-open cavity structure 102, connected by a sliding mechanism 103. The length of the geometric path can be adjusted via this mechanism. A 3D schematic diagram is shown below. Figure 3The semi-open cavity structure is made of ferrous metal. Terminal S1 of the semi-open cavity is the signal input terminal, and terminal S2 is the signal output terminal. There are 12 pluggable modules 104 within the semi-open cavity. These pluggable modules can accommodate mirrors and absorbing materials. Placing the mirror at pluggable modules 1 and 2 via the I-shaped semi-open cavity provides a fixed short path, while placing it at 3 and 4 and adjusting the U-shaped semi-open cavity via a sliding track provides an adjustable long path. Pluggable modules at points 5, 6, 7, 8, 9, 10, 11, and 12 can accommodate absorbing materials of different thicknesses, allowing adjustment of the path gain for reflection / absorption / semi-absorption modes without altering the geometric dimensions.

[0044] Example 2

[0045] Based on Example 1, such as Figure 4 As shown, the dynamic range of the acquisition path delay of the terahertz calibration module based on reflection mode is illustrated by the following principles and steps:

[0046] Step 1: Record the initial position t0 of the THz pulse of the terahertz system under test when the calibration module is not installed.

[0047] Step 2: Place the calibration module into the terahertz channel to be measured, with the input end coaxial with the optical axis of the terahertz source and the output end aligned with the center of the detector, and tighten the positioning screw.

[0048] Step 3: Maintaining the above geometric position, place the pluggable modules at points 1 and 2 onto the reflector to record the time domain position t1 of the THz pulse acquired along the fixed short path.

[0049] Step 4: Based on steps 2 and 3, the fixed short path delay Δt1 = t1 - t0 can be obtained.

[0050] Step 5: While keeping the original geometry unchanged, move the reflectors in the original plug-in modules 1 and 2 to positions 3 and 4.

[0051] Step 6: Adjust the sliding mechanism to make the displacement Δx i Starting from 0 cm and incrementing at equal intervals, the time-domain position t of the corresponding THz pulse for the terahertz system under test is recorded simultaneously. i .

[0052] Step 7: Based on steps 5 and 6, the adjustable long path delay Δt can be obtained. i =t i -t0, i=2, 3, 4...

[0053] Step 8: By following steps 4 and 7, the traceable total path delay dynamic range Δt of this calibration system is obtained. max ~Δt min .

[0054] Example 3

[0055] Based on Examples 1 and 2, the terahertz calibration module based on the absorption mode calibrates the amplitude linearity and sensitivity of the system under test. The specific principle and steps are as follows:

[0056] Step 1: With the optical path and mechanical positioning unchanged, insert the same absorbing material of thickness d0 into the plug-in modules 5, 6, 7, 8, 9, 10, 11 and 12 of the calibration module, and collect the time domain waveform, record the peak-to-peak amplitude A0 and the corresponding frequency domain amplitude spectrum as the 0 dB attenuation reference.

[0057] Step 2: Replace all plug-in modules 5, 6, 7, 8, 9, 10, 11, and 12 with the same thickness of absorbing material, i.e., replace them sequentially with different thicknesses. The absorbing material. Each time it is replaced, the process in step 1 is repeated: time-domain waveform acquisition → extraction of peak value - peak amplitude Aᵢ → storage of frequency domain amplitude spectrum.

[0058] Step 3: After completing the full thickness scan, plot the Aᵢ–dᵢ curve. Use the least squares method to fit the slope to obtain the amplitude attenuation coefficient α (dB / mm) of the terahertz channel system. The intercept corresponds to the lower limit of system sensitivity A. min This allows for full-range calibration of amplitude linearity and sensitivity.

[0059] Example 4

[0060] Building upon Examples 1, 2, and 3, this paper describes the principle and steps for calibrating the linearity and sensitivity of the system under test in more complex scenarios based on the semi-absorption mode:

[0061] The pluggable modules are empty / with the same thickness of absorbing material at positions 7, 8, 9 and 10. The pluggable modules at positions 5, 6, 11 and 12 are filled with the same thickness of absorbing material / empty. The optical path is kept fixed. The acquisition and fitting process of Example 3 is repeated to realize the amplitude linearity and sensitivity verification in the semi-absorption mode.

[0062] It should be noted that the above-mentioned technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this invention specification; and, for those skilled in the art, improvements or modifications can be made based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

[0063] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0064] The above-described 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. Such 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, and should all be included within the protection scope of the present invention.

Claims

1. A portable terahertz calibration module based on an adjustable dual-path structure, characterized in that, include: A dual-channel geometry structure, comprising an I-shaped semi-open cavity structure and a U-shaped semi-open cavity structure, wherein the I-shaped semi-open cavity structure forms a fixed short path and the U-shaped semi-open cavity structure forms a long path with adjustable length. A sliding mechanism connects the I-shaped semi-open cavity structure and the U-shaped semi-open cavity structure, and is used to adjust the geometric length of the U-shaped semi-open cavity structure; A pluggable module is located at multiple wall-side positions of the dual-channel geometry to switch between the reflector and the absorbing material, thereby enabling switching between reflection mode, absorption mode and semi-absorption mode. The dual-channel geometry is made of ferrous metal, with the left end being the signal input terminal S1 and the right end being the signal output terminal S2.

2. The portable terahertz calibration module based on an adjustable dual-path structure according to claim 1, characterized in that, The pluggable module has 12 preset positions, specifically defined as follows: The first position is located near the signal input terminal S1 within the I-shaped semi-open cavity structure; The second position is located near the signal output end S2 within the I-shaped semi-open cavity structure, and is mirror-aligned with the first position. The third position is located on the left side of the turning angle within the U-shaped semi-open cavity structure; The fourth position is located on the right side of the turning angle within the U-shaped semi-open cavity structure, mirror-aligned with the third position; The fifth position is located on the inner wall of the vertical path in the middle of the left side of the U-shaped semi-open cavity structure; The sixth position is positioned opposite the fifth position and aligned with it. The seventh position is located on the left inner wall of the top path of the U-shaped semi-open cavity structure; The eighth position is set opposite the seventh position, and aligned with the seventh position; The ninth and tenth positions are located on the right inner wall of the top path of the U-shaped semi-open cavity structure, mirroring and aligned with the seventh and eighth positions. The eleventh and twelfth positions are located on the inner wall of the vertical path in the middle right side of the U-shaped semi-open cavity structure; they are mirror-aligned with the fifth and sixth positions.

3. The portable terahertz calibration module based on an adjustable dual-path structure according to claim 2, characterized in that, When the first and second positions are reflectors, they are used to form a fixed short path in reflection mode.

4. The portable terahertz calibration module based on an adjustable dual-path structure according to claim 2, characterized in that, When the third and fourth positions are reflectors, they are used to adjust the length of the long path in reflection mode via a sliding mechanism.

5. The portable terahertz calibration module based on an adjustable dual-path structure according to claim 2, characterized in that, The absorbing material at positions 5 to 12.

6. The portable terahertz calibration module based on an adjustable dual-path structure according to claim 5, characterized in that, The absorbing material is of different thicknesses and is used to adjust the path gain in different modes.

7. The portable terahertz calibration module based on an adjustable dual-path structure according to claims 1 and 5, characterized in that, The pluggable module can be switched at any position to a reflector or a microwave absorbing material of different thicknesses to achieve reflection, absorption and semi-absorption modes.

8. The portable terahertz calibration module based on an adjustable dual-path structure according to any one of claims 1 to 7, characterized in that, The portable terahertz calibration module is used to calibrate the time delay dynamic range, amplitude linearity, and sensitivity of terahertz systems in the 0.1–10 THz frequency band.

9. The portable terahertz calibration module based on an adjustable dual-path structure according to claim 8, characterized in that, The time delay dynamic range calibration is achieved through the reflection mode, and the amplitude linearity and sensitivity calibration are achieved through the absorption mode and the semi-absorption mode.

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