System and method for measuring amplitude and phase characteristics of a metamaterial periodic structure unit

Abstract

This invention belongs to the field of microwave measurement and relates to a measurement system and method for the amplitude and phase characteristics of metamaterial periodic structural units. The measurement system includes a measuring fixture, an external field source, a periodic structural unit under test, and a vector network analyzer. The vector network analyzer is electrically connected to the measuring fixture. The periodic structural unit under test is placed inside the measuring fixture, and the external field source is placed outside the measuring fixture. The external field source inputs an external signal to the periodic structural unit under test, and the vector network analyzer measures the reflection parameters of the measurement system under the influence of the external signal. The measurement method involves placing the periodic structural unit under test at the gap between the short surface and the inner conductor, applying different external signals and recording the reflection parameters of the measurement system. Based on the reflection parameters, the amplitude and phase characteristics of the periodic structural unit under test are calculated using electromagnetic theory. This invention realizes the measurement of the amplitude and phase characteristics of metamaterial periodic structural units. The measurement system has a simple structure, is easy to operate, and provides accurate measurement results.

Description

Technical Field

[0001] This invention belongs to the field of microwave measurement technology, specifically relating to a system and method for measuring the amplitude and phase characteristics of metamaterial periodic structural units. Background Technology

[0002] In the field of electromagnetics, achieving free control over the scattering characteristics of electromagnetic waves has always been a highly challenging research topic. Traditional optical devices can achieve beam control by modulating the dynamic phase, but this imposes many limitations on the structure, shape, and volume of the devices, resulting in high system complexity, difficult fabrication, and challenges in miniaturization and integration. Therefore, in the microwave band, a novel structural functional material (i.e., metamaterial) based on introducing abrupt phase changes through structural design and constructing a structure through the organic arrangement of these abrupt phase changes has been proposed, providing a new research approach for electromagnetic scattering control.

[0003] Currently, achieving high-resolution digital programmability is a hot research topic for metamaterials. Metamaterials are generally composed of arrays of multiple periodic structural units as basic units. Different structural units have different amplitude and phase characteristics, thus enabling precise control of electromagnetic waves. It can be said that the amplitude and phase characteristics of different metamaterial structural units determine the metamaterial structure's ability to control electromagnetic waves. Existing metamaterial structural units mainly have two types of key control elements: voltage-controlled and light-intensity-controlled. When the control elements in a metamaterial structural unit are irradiated with different voltages or light intensities, the amplitude and phase characteristics of the periodic structural units change, thereby allowing for the control of electromagnetic waves.

[0004] Currently, whether metamaterials can correctly achieve electromagnetic wave manipulation usually requires the fabrication of a complete array of metamaterial structural units before measurement. If one or more periodic structural units in the array have design deviations, the entire fabricated metamaterial structural unit array often becomes unusable, resulting in significant financial and material losses.

[0005] Therefore, how to build a measurement system that can achieve high-precision measurement of the amplitude and phase characteristics of metamaterial periodic structural units has become the current research focus. Summary of the Invention

[0006] To address the problems existing in the background technology, the purpose of this invention is to provide a system and method for measuring the amplitude and phase characteristics of metamaterial periodic structural units. This invention utilizes a terminal short-circuit stripline, an external field source, a DC blocker, and a vector network analyzer. Based on the different responses of the control elements in the periodic structural unit under test to different external field source magnitudes, and by measuring the changes in the reflection parameters of the measurement system, the amplitude and phase characteristics of the periodic structural unit under test under different external field sources are obtained through inversion, thus realizing the measurement of the amplitude and phase characteristics of metamaterial periodic structural units.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A system for measuring the amplitude and phase characteristics of metamaterial periodic structural units includes a measuring fixture, an external field source, a periodic structural unit under test, and a vector network analyzer. The periodic structural unit under test is a circuit unit with resonant characteristics, wherein the upper surface is a patterned layer with a control element for sensing the external field source loaded on it, and the lower surface is a metal ground. The vector network analyzer is electrically connected to the measuring fixture. The periodic structural unit under test is placed inside the measuring fixture, and the external field source is placed outside the measuring fixture. The external field source inputs an external signal to the periodic structural unit under test. The vector network analyzer measures the reflection parameters of the measuring system under the influence of the external signal on the periodic structural unit under test, and calculates the amplitude and phase characteristics of the periodic structural unit under test under the influence of the external signal using electromagnetic theory.

[0009] Preferably, the measuring fixture uses a terminal short-circuit stripline, with a gap between the conductor in the terminal short-circuit stripline and the short surface for loading the periodic structural unit to be tested. The metal ground of the periodic structural unit to be tested is in parallel contact with the short surface side of the terminal short-circuit stripline, and the pattern layer is in contact with the conductor in the terminal short-circuit stripline.

[0010] Preferably, the control element of the periodic structural unit under test is voltage-controlled, the external field source is an adjustable DC voltage source, and two small holes are provided on the short-circuit surface of the terminal short-circuit strip. The adjustable DC voltage source supplies power to the control element in the periodic structural unit under test through a DC line passing through the two small holes.

[0011] Preferably, the vector network analyzer is connected to a DC blocker via a coaxial cable, and the DC blocker is connected to a terminal short-circuit stripline.

[0012] Preferably, the control element of the periodic structural unit under test is controlled by a light source. The external field source is a light source. The light signal emitted by the light source reaches the periodic structural unit under test and the optical power meter after passing through an optical link. The optical link includes an attenuator, a beam splitter, and a mirror. The light source, attenuator, beam splitter, and mirror are located on the same straight line. One optical signal after being split by the beam splitter reaches the optical power meter. A through hole for the light signal to pass through is opened on the lower surface of the terminal short-circuit stripline corresponding to the position of the periodic structural unit under test. The through hole on the lower surface of the mirror and the terminal short-circuit stripline are located on the same straight line. The other optical signal after being split by the beam splitter reaches the periodic structural unit under test through the mirror.

[0013] Preferably, the light source is a broadband light source.

[0014] A method for measuring the amplitude-phase properties of metamaterial periodic structural units, using the aforementioned metamaterial periodic structural unit amplitude-phase property measurement system, includes the following steps:

[0015] Without loading the periodic structural unit under test, the measurement system is short-circuited calibrated.

[0016] The voltage-controlled periodic structural unit under test is placed at the gap between the short-circuit surface of the terminal short-circuit strip and the inner conductor. The adjustable DC voltage source is set to zero, and the reflection parameter S11_00 of the measurement system is recorded at this time.

[0017] The output voltage value of the adjustable DC voltage source is adjusted to U1~U n And record the reflection parameters S11_10~S11_n0 of the measurement system;

[0018] Based on the above steps, the reflection parameters S11 of the measured system under different output voltage values ​​of the loaded periodic structural unit under test are obtained, and the amplitude and phase characteristics of the periodic structural unit under test are calculated by electromagnetic theory.

[0019] Preferably, the amplitude and phase characteristics of the periodic structural unit under test are calculated using electromagnetic theory. The specific process is as follows:

[0020] Calculate the amplitude of the periodic structural element under test:

[0021]

[0022] Calculate the phase of the periodic structural element under test:

[0023]

[0024] in, denoted as the electromagnetic wave phase shift constant in the terminal short-circuited stripline, and d is the physical thickness dimension of the periodic structural unit under test.

[0025] A method for measuring the amplitude-phase properties of metamaterial periodic structural units, using the aforementioned metamaterial periodic structural unit amplitude-phase property measurement system, includes the following steps:

[0026] Without loading the periodic structural unit under test, the measurement system is short-circuited calibrated.

[0027] The test periodic structural unit, controlled by the light source, is placed at the gap between the short surface of the terminal short-circuit strip and the inner conductor. The output light intensity of the light source is set to zero, and the reflection parameter S11_01 of the measurement system is recorded at this time.

[0028] Adjust the output power of the light source to P1~P n And record the reflection parameters S11_11~S11_n1 of the measurement system;

[0029] Based on the above steps, the reflection parameters S11 of the measured system under different output light intensities of the loaded periodic structural unit are obtained, and the amplitude and phase characteristics of the periodic structural unit under test are calculated by electromagnetic theory.

[0030] Preferably, the amplitude and phase characteristics of the periodic structural unit under test are calculated using electromagnetic theory. The specific process is as follows:

[0031] Calculate the amplitude of the periodic structural element under test:

[0032]

[0033] Calculate the phase of the periodic structural element under test:

[0034]

[0035] in, denoted as the electromagnetic wave phase shift constant in the terminal short-circuited stripline, and d is the physical thickness dimension of the periodic structural unit under test.

[0036] In summary, based on the above technical solutions, the beneficial effects of the present invention are as follows:

[0037] This invention provides a system and method for measuring the amplitude and phase characteristics of metamaterial periodic structural units. This invention uses only commonly used instruments such as a vector network analyzer, a terminal short-circuited stripline, an adjustable DC voltage source, a light source, and an optical power meter to achieve the measurement of the amplitude and phase characteristics of metamaterial periodic structural units. The measurement system has a simple structure, is easy to operate, and provides accurate measurement results. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the metamaterial periodic structural unit amplitude and phase characteristic measurement system of the present invention.

[0039] Among them, 1 is a vector network analyzer, 2 is a DC blocker, 3 is a terminal short-circuit stripline, 4 is an adjustable DC voltage source, 5 is the periodic structural unit under test, 6 is a light source, 7 is an attenuator, 8 is a beam splitter, 9 is a mirror, and 10 is an optical power meter. Detailed Implementation

[0040] Example 1

[0041] A system for measuring the amplitude and phase properties of metamaterial periodic structural units, the schematic diagram of which is shown below. Figure 1As shown, the system includes a measuring fixture, an external field source, a DC blocker 2, a periodic structural unit under test 5, and a vector network analyzer 1. The measuring fixture is a short-circuited stripline 3; the external field source includes an adjustable DC voltage source 4, a light source 6, an attenuator 7, a beam splitter 8, an optical power meter 10, and a mirror 9; the DC blocker 2 protects the vector network analyzer 1 from external DC voltage signals; the periodic structural unit under test 5 is placed at the short-circuited surface of the short-circuited stripline 3; and the vector network analyzer 1 is used to acquire the reflection parameters of the measuring system. A stripline is a transmission line structure, and loading a metal plate onto one end of it constitutes a short-circuited stripline—this is a consensus in this field.

[0042] The conductor in the terminal short-circuit strip 3 has a 2mm gap between it and the short surface on one side. The gap is used to load the periodic structure unit 5 to be tested.

[0043] The periodic structural unit 5 under test is a circuit unit with resonant characteristics. Its upper surface is a patterned layer with a control element that senses external field sources, and its lower surface is a metal ground.

[0044] The periodic structural unit 5 to be tested is divided into two types: one is a periodic structural unit whose control element is controlled by voltage, and the other is a periodic structural unit whose control element is controlled by light source.

[0045] There are two small holes on the short-circuit surface of the terminal short-circuit strip 3.

[0046] The adjustable DC voltage source 4 supplies power to the control element in the periodic structure unit 5 under test by passing a DC line through a small hole in the short surface of the terminal short-circuit strip 3.

[0047] The light source 6 reaches the control element in the periodic structure unit 5 under test after passing through the optical link. In the optical link, the light source 6 is a broadband light source used to provide the original optical signal; the attenuator 7 is used to attenuate the irradiance of the original optical signal; and the beam splitter 8 is used to split the attenuated optical signal, one path going to the optical power meter 10 for measuring the intensity of the optical signal, and the other path passing through the mirror 9 to reach the control element in the periodic structure unit 5 under test.

[0048] The vector network analyzer 1 is connected to the DC blocker 2 via a coaxial cable. The DC blocker 2 is connected to the terminal short-circuit stripline 3 to extract the reflection parameters of the periodic structural unit 5 under different external field sources after being loaded into the measurement system. The DC blocker 2 is used to prevent voltage signal crosstalk from the adjustable DC power supply 4 to the vector network analyzer 1. The DC blocker 2 is connected to the input port of the terminal short-circuit stripline 3.

[0049] Example 2

[0050] A method for measuring the amplitude-phase properties of metamaterial periodic structural units, using the aforementioned metamaterial periodic structural unit amplitude-phase property measurement system, includes the following steps:

[0051] Step 1. Connect the measurement system according to the measurement system schematic diagram, and power on the vector network analyzer 1 to allow it to warm up.

[0052] Step 2. Without loading the periodic structural unit 5 under test, perform short-circuit calibration on the measurement system;

[0053] Step 3. Place the voltage-controlled periodic structure unit 5 under test at the gap between the short-circuit surface of the terminal short-circuit strip 3 and the inner conductor, set the adjustable DC voltage source 4 to zero, and record the reflection parameter S11_00 of the measurement system at this time.

[0054] Step 4. Adjust the output voltage of the adjustable DC voltage source 4 to U1, and record the reflection parameters S11_10 of the measurement system;

[0055] Step 5. Repeat step 4, adjusting the output voltage value of the adjustable DC voltage source 4 to U2~U n And record the reflection parameters S11_20~S11_n0 of the measurement system;

[0056] Step 6. Place the test periodic structure unit 5, which is controlled by the light source, at the gap between the short surface of the terminal short-circuit strip 3 and the inner conductor. Set the output light intensity of the light source 6 to zero and record the reflection parameter S11_01 of the measurement system at this time.

[0057] Step 7. Adjust the output power of light source 6 to P1, and record the reflection parameters S11_11 of the measurement system;

[0058] Step 8. Repeat step 7, adjusting the output light intensity of light source 6 to P1~P n And record the reflection parameters S11_21~S11_n1 of the measurement system.

[0059] Based on the reflection parameters S11 of the measurement system obtained from the above steps for loading the periodic structural unit 5 under different external field sources, the amplitude and phase characteristics of the periodic structural unit 5 under test are then obtained through basic electromagnetic theory. The specific process is as follows:

[0060] Calculate the amplitude of the periodic structural unit 5 to be tested:

[0061]

[0062] Calculate the phase of the periodic structural unit 5 under test:

[0063]

[0064] In formulas (1) and (2), S 11These are several reflection parameters obtained in steps 3 to 8. denoted as , where f is the electromagnetic wave phase shift constant in the terminal short-circuited stripline 3, f is the operating frequency of the terminal short-circuited stripline 3, and d is the physical thickness of the periodic structural unit 5 under test. μ0ε0 represents the vacuum permeability and vacuum permittivity, respectively. It was obtained by direct measurement using a vector network analyzer 1.

[0065] The amplitude-phase characteristics of the metamaterial periodic structural unit can be obtained from equations (1) and (2). The constants in equations 1 and 2 are 10, 20, and 2, and these values ​​are common knowledge.

[0066] The above description is merely a specific embodiment of the present invention, and any feature disclosed in this specification may be replaced by other equivalent or similar features unless specifically stated otherwise; all disclosed features, or steps in all methods or processes, may be combined in any manner except for mutually exclusive features and / or steps.

Claims

1. A system for measuring the amplitude and phase characteristics of metamaterial periodic structural units, characterized in that, The system includes a measuring fixture, an external field source, a periodic structural unit under test, and a vector network analyzer. The periodic structural unit under test is a circuit unit with resonant characteristics, wherein the upper surface is a patterned layer with a control element for sensing the external field source, and the lower surface is a metal ground. The vector network analyzer is electrically connected to the measuring fixture. The periodic structural unit under test is placed inside the measuring fixture, and the external field source is placed outside the measuring fixture. The external field source inputs an external signal to the periodic structural unit under test. The vector network analyzer measures the reflection parameters of the measuring system under the influence of the external signal on the periodic structural unit under test, and calculates the amplitude and phase characteristics of the periodic structural unit under test under the influence of the external signal using electromagnetic theory. The measuring fixture uses a terminal short-circuit stripline. A gap is left between the conductor in the terminal short-circuit stripline and the short surface for loading the periodic structural unit to be tested. The metal ground of the periodic structural unit to be tested is in parallel contact with the short surface side of the terminal short-circuit stripline, and the pattern layer is in contact with the conductor in the terminal short-circuit stripline.

2. The metamaterial periodic structural unit amplitude and phase characteristic measurement system according to claim 1, characterized in that, The control element of the periodic structural unit under test is voltage-controlled. The external field source is an adjustable DC voltage source. Two small holes are provided on the short-circuit surface of the terminal short-circuit strip. The adjustable DC voltage source supplies power to the control element in the periodic structural unit under test through a DC line passing through the two small holes.

3. The metamaterial periodic structural unit amplitude and phase characteristic measurement system according to claim 2, characterized in that, The vector network analyzer is connected to a DC blocker via a coaxial cable, and the DC blocker is connected to a terminal short-circuit stripline.

4. The metamaterial periodic structure unit amplitude and phase characteristic measurement system according to claim 1, characterized in that, The control element of the periodic structural unit under test is controlled by a light source. The external field source is the light source. The light signal emitted by the light source reaches the periodic structural unit under test and the optical power meter after passing through an optical link. The optical link includes an attenuator, a beam splitter, and a mirror. The light source, attenuator, beam splitter, and mirror are located on the same straight line. One optical signal after being split by the beam splitter reaches the optical power meter. A through hole for the light signal to pass through is opened on the lower surface of the terminal short-circuit stripline corresponding to the position of the periodic structural unit under test. The through hole on the lower surface of the mirror and the terminal short-circuit stripline are located on the same straight line. The other optical signal after being split by the beam splitter reaches the periodic structural unit under test through the mirror.

5. The metamaterial periodic structural unit amplitude and phase characteristic measurement system according to claim 4, characterized in that, The light source is a broadband light source.

6. A method for measuring the amplitude-phase characteristics of metamaterial periodic structural units, characterized in that, The application of the metamaterial periodic structural unit amplitude-phase characteristic measurement system as described in claim 2 includes the following steps: Without loading the periodic structural unit under test, the measurement system is short-circuited calibrated. The voltage-controlled periodic structural unit under test is placed at the gap between the short-circuit surface of the terminal short-circuit strip and the inner conductor. The adjustable DC voltage source is set to zero, and the reflection parameter S11_00 of the measurement system is recorded at this time. Adjust the output voltage value of the adjustable DC voltage source to U1~U n And record the reflection parameters S11_10~S11_n0 of the measurement system; Based on the above steps, the reflection parameters S11 of the measured system under different output voltage values ​​of the loaded periodic structural unit under test are obtained, and the amplitude and phase characteristics of the periodic structural unit under test are calculated by electromagnetic theory.

7. The method for measuring the amplitude and phase characteristics of metamaterial periodic structural units according to claim 6, characterized in that, The amplitude and phase characteristics of the periodic structural unit under test were calculated using electromagnetic theory. The specific process is as follows: Calculate the amplitude of the periodic structural element under test: (1) Calculate the phase of the periodic structural element under test: (2) in, The phase shift constant of the electromagnetic wave in the terminal short-circuited stripline. The physical thickness dimension of the periodic structural unit to be tested.

8. A method for measuring the amplitude and phase characteristics of metamaterial periodic structural units, characterized in that, The application of the metamaterial periodic structural unit amplitude-phase characteristic measurement system as described in claim 4 includes the following steps: Without loading the periodic structural unit under test, the measurement system is short-circuited calibrated. The test periodic structural unit, controlled by the light source, is placed at the gap between the short surface of the terminal short-circuit strip and the inner conductor. The output light intensity of the light source is set to zero, and the reflection parameter S11_01 of the measurement system is recorded at this time. Adjust the output power of the light source to P1~P n And record the reflection parameters S11_11~S11_n1 of the measurement system; Based on the above steps, the reflection parameters S11 of the measured system under different output light intensities of the loaded periodic structural unit are obtained, and the amplitude and phase characteristics of the periodic structural unit under test are calculated by electromagnetic theory.

9. The method for measuring the amplitude and phase characteristics of metamaterial periodic structural units according to claim 8, characterized in that, The amplitude and phase characteristics of the periodic structural unit under test were calculated using electromagnetic theory. The specific process is as follows: Calculate the amplitude of the periodic structural element under test: (1) Calculate the phase of the periodic structural element under test: (2) in, The phase shift constant of the electromagnetic wave in the terminal short-circuited stripline. The physical thickness dimension of the periodic structural unit to be tested.

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