Coaxial s-parameter phase standard and its design, implementation and calibration method

Abstract

The application discloses a coaxial S parameter phase standard device and a design, implementation and calibration method thereof. The method comprises the following steps: S1, determining the type of the coaxial S parameter phase standard device according to a working frequency band and determining the inner diameter of the outer conductor and the outer diameter of the inner conductor of the coaxial S parameter phase standard device; S2, determining the length value corresponding to the phase change covering-180°~+180° in the whole working frequency band as the length of the coaxial S parameter phase standard device; S3, calibrating the physical size of the inner diameter of the outer conductor, the outer diameter of the inner conductor and the length of the coaxial S parameter phase standard device after processing; S4, calculating the phase shift value corresponding to each frequency in the working frequency band and setting the phase shift value as the standard value corresponding to each frequency of the coaxial S parameter phase standard device. The calibration value of the coaxial S parameter phase standard device can be calculated through the physical size, and the coaxial S parameter phase standard device can be used as the highest standard device of transmission phase.

Description

Technical Field

[0001] This invention belongs to the field of phase standard technology, specifically relating to a coaxial S-parameter phase standard and its design, implementation, and calibration method. Background Technology

[0002] Vector network analyzers are instruments used to measure microwave networks such as microwave amplifiers, couplers, power dividers, and isolators. They are widely used in various stages of microwave device research, manufacturing, and calibration. Because vector network analyzers have systematic errors, they must be calibrated before use. After calibration, to verify the instrument's calibration status, a series of calibration standards are used to test the vector network analyzer. These standards mainly include reflection amplitude standards, transmission amplitude standards, and transmission phase standards. Reflection amplitude standards are primarily implemented using standard mismatches or mismatched air lines, transmission amplitude standards are primarily implemented using standard attenuators, and transmission phase standards are primarily implemented using ideally matched transmission lines. In frequency bands below 67 GHz, microwave transmission lines are typically coaxial transmission lines.

[0003] Traditional coaxial S-parameter phase standards use air-medium transmission lines with dielectric support. However, because the dielectric constant of the supporting medium is different from that of air, the propagation speed of electromagnetic waves in the supporting medium is different from that in air. There is a difference between the theoretical value of the transmission phase and the theoretical value calculated from physical dimensions. Therefore, the calibration value of this traditional coaxial S-parameter phase standard cannot be completely obtained from the calculation using physical dimensions, and it is not suitable as the highest standard for transmission phase. Summary of the Invention

[0004] The purpose of this invention is to provide a coaxial S-parameter phase standard, its design, implementation, and calibration method, which enables the calibration value of the coaxial S-parameter phase standard to be calculated entirely from the physical dimensions, and thus can be used as the highest standard for transmission phase.

[0005] To achieve the above objectives, according to one aspect of this application, a design, implementation, and calibration method for a coaxial S-parameter phase standard is provided, comprising:

[0006] Step S1: Determine the type of the coaxial S-parameter phase standard based on the operating frequency band, and determine the inner diameter of the outer conductor and the outer diameter of the inner conductor of the coaxial S-parameter phase standard;

[0007] Step S2: Determine the length value corresponding to the phase change covering -180° to +180° within the entire operating frequency band as the length of the coaxial S-parameter phase standard;

[0008] Step S3: Perform physical dimension calibration on the inner diameter of the outer conductor, the outer diameter of the inner conductor, and the length of the coaxial S-parameter phase standard after processing;

[0009] Step S4: Calculate the phase shift value corresponding to each frequency within the operating frequency band, and set the phase shift value as the standard value corresponding to each frequency of the coaxial S-parameter phase standard.

[0010] Furthermore, in step S1, the operating frequency band DC to 18GHz uses an N-type or APC-7mm connector, the operating frequency band DC to 26.5GHz uses an APC-3.5mm connector, and the operating frequency band DC to 50GHz uses an APC-2.4mm connector.

[0011] Furthermore, the inner diameter of the outer conductor of the APC-3.5mm connector is Φ o_in The outer diameter of the inner conductor is Φ i_out , where Φ o_in 3.5mm, Φ i_out It is 1.52mm.

[0012] Further, in step S4, the step of calculating the phase shift value corresponding to each frequency within the operating frequency band includes:

[0013] Select the frequency point required for actual calibration;

[0014] Calculate the wavelength corresponding to each frequency based on the frequency point;

[0015] Calculate the phase shift corresponding to each frequency.

[0016] Furthermore, the wavelength is calculated using the formula λ = c / f, where λ is the wavelength in meters; c is the speed of light in meters per second; and f is the frequency in Hertz.

[0017] Furthermore, the phase shift is expressed using the formula... Calculate, where, The phase shift is expressed in radians; l is the length of the calibrated coaxial S-parameter phase standard in meters.

[0018] Furthermore, in step S2, the length of the coaxial S-parameter phase standard is 20mm to 55mm.

[0019] Furthermore, the inner conductor includes a first segment and a second segment, which are fixedly connected. The first segment is made of an elastic conductive material, and the second segment is made of a rigid conductive material.

[0020] Furthermore, the elastic conductive material is beryllium bronze or tin bronze, and the rigid conductive material is brass or stainless steel.

[0021] Furthermore, the first segment is located at the female end of the inner conductor, and the second segment is located at the male end of the inner conductor.

[0022] By applying the technical solution of this invention, a coaxial S-parameter phase standard can be designed, implemented, and calibrated through the following steps.

[0023] Step S1: Determine the type of coaxial S-parameter phase standard based on the operating frequency band, and determine the inner diameter of the outer conductor and the outer diameter of the inner conductor of the coaxial S-parameter phase standard;

[0024] Step S2: Determine the length value corresponding to the phase change covering -180° to +180° across the entire operating frequency band as the length of the coaxial S-parameter phase standard;

[0025] Step S3: Perform physical dimension calibration on the inner diameter of the outer conductor, the outer diameter of the inner conductor, and the length of the coaxial S-parameter phase standard after processing;

[0026] Step S4: Calculate the phase shift value corresponding to each frequency within the operating frequency band, and set the phase shift value as the standard value corresponding to each frequency of the coaxial S-parameter phase standard. Specifically, the wavelength value is calculated using the formula λ = c / f. Subsequently, the formula... Calculate the phase shift value for each frequency.

[0027] The coaxial S-parameter phase standard designed in this way has a uniform and continuous dielectric between its inner and outer conductors. The theoretical value of the phase shift of this coaxial S-parameter phase standard can be calculated using the calibration values ​​of its physical dimensions. This theoretical value is then used as the calibration value for the transmission phase to verify the measurement accuracy of the transmission phase in a vector network analyzer. This method allows the transmission phase standard to be traced back to its length, determining its theoretical transmission phase value through physical dimension calibration. The calibration results are highly accurate and are particularly suitable for use as the highest standard for transmission phase.

[0028] Furthermore, this application divides the inner conductor into a first segment and a second segment. The first segment, the female end, is made of tin bronze and beryllium bronze, while the second segment, the male end, is made of brass or stainless steel. This ensures the voltage standing wave ratio (VSWR) at the female end of the inner conductor and the concentricity between the inner and outer conductors, while also guaranteeing its technical specifications. The structure is simple, easy to implement, and low in cost. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 This is a flowchart illustrating the design, implementation, and calibration method of the coaxial S-parameter phase standard disclosed in the embodiments of this application;

[0031] Figure 2 This is a cross-sectional view of the coaxial S-parameter phase standard disclosed in the embodiments of this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 10. Coaxial S-parameter phase standard; 11. Outer conductor; 12. Inner conductor; 121. First segment; 122. Second segment. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and are not to a precise scale, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0035] It should be noted that, in order to clearly illustrate the content of this invention, several embodiments are provided to further explain different implementations of the invention. These embodiments are enumerated rather than exhaustive. Furthermore, for the sake of brevity, content mentioned in the preceding embodiments is often omitted in the following embodiments. Therefore, content not mentioned in the later embodiments can be referred to in the preceding embodiments.

[0036] See Figures 1 to 2 As shown, according to an embodiment of this application, a design, implementation, and calibration method for a coaxial S-parameter phase standard is provided. This design, implementation, and calibration method includes:

[0037] Step S1: Determine the type of the coaxial S-parameter phase standard 10 according to the operating frequency band, and determine the inner diameter of the outer conductor 11 and the outer diameter of the inner conductor 12 of the coaxial S-parameter phase standard 10.

[0038] In this step, the type of coaxial S-parameter phase standard 10 is determined according to its operating frequency band: N-type or APC-7mm connectors are used for the operating frequency band DC to 18GHz, APC-3.5mm connectors are used for the operating frequency band DC to 26.5GHz, and APC-2.4mm connectors are used for the operating frequency band DC to 50GHz. After determining the required type of coaxial S-parameter phase standard 10 based on the operating frequency band, the inner diameter of the outer conductor 11 and the outer diameter of the inner conductor 12 can be determined according to this type of coaxial S-parameter phase standard.

[0039] Specifically, when the design frequency band is DC to 26.5 GHz, the standard connector type is the APC-3.5mm connector. Based on relevant connector standards, the inner diameter of the outer conductor of the APC-3.5mm connector can be determined as Φ. o_in The inner conductor outer diameter is Φ, which is 3.5mm. i_out It is 1.52mm.

[0040] Step S2: Determine the length value corresponding to the phase change covering -180° to +180° throughout the entire operating frequency band as the length of the coaxial S-parameter phase standard 10;

[0041] Specifically, in this step, the length of the coaxial S-parameter phase standard 10 is determined as the length of the actual required coaxial S-parameter phase standard 10, which covers a phase change of -180° to +180° in its operating frequency band.

[0042] Furthermore, the length of the coaxial S-parameter phase standard 10 is 20mm to 55mm, for example, 20mm, 35mm, 50mm, and 55mm. When the length of the coaxial S-parameter phase standard 10 is less than 20mm, it is inconvenient to connect with other test systems (vector network analyzers); when the length of the coaxial S-parameter phase standard 10 is greater than 55mm, it is difficult to guarantee the coaxiality of the outer conductor 11 and the inner conductor 12 during processing. In other words, when the length of the coaxial S-parameter phase standard 10 is 20mm to 55mm, it can both ensure convenient connection with other test systems and guarantee the coaxiality of the outer conductor 11 and the inner conductor 12 during processing.

[0043] Step S3: Perform physical dimension calibration on the inner diameter of the outer conductor 11, the outer diameter of the inner conductor 12, and the length of the coaxial S-parameter phase standard 10 after processing.

[0044] After completing the first two steps, the required coaxial S-parameter phase standard 10 can be manufactured. Since the inner diameter of the outer conductor 11, the outer diameter of the inner conductor 12, and the length of the manufactured coaxial S-parameter phase standard 10 will have errors, it needs to be calibrated to obtain an accurate value. The calibrated value is the value we will use for subsequent calculations.

[0045] Step S4: Calculate the phase shift value corresponding to each frequency within the operating frequency band, and set the phase shift value as the standard value corresponding to each frequency of the coaxial S-parameter phase standard 10.

[0046] In step S4, the steps for calculating the phase shift value corresponding to each frequency within the working frequency band include: selecting the frequency point to be calibrated; calculating the wavelength corresponding to each frequency based on the frequency point; and calculating the phase shift corresponding to each frequency.

[0047] Wavelength is calculated using the formula λ = c / f, where λ is the wavelength in meters, c is the speed of light in meters per second, and f is the frequency in Hertz.

[0048] Phase shift is expressed by formula Calculate, where: The phase shift is expressed in radians, and l is the length of the calibrated coaxial S-parameter phase standard 10, expressed in meters.

[0049] Taking the DC~26.5GHz frequency band as an example, the specific operation of this method is as follows:

[0050] Within the frequency band of DC to 26.5 GHz, the standard coaxial cable uses a 3.5 mm coaxial cable with an outer conductor inner diameter of Φ. o_in =3.5mm, outer diameter Φ of inner conductor i_out =1.52mm. The APC-3.5mm connector is commonly used in this frequency band.

[0051] Step S1: Determine the type of the coaxial S-parameter phase standard 10 based on the operating frequency band, and determine the inner diameter of the outer conductor 11 and the outer diameter of the inner conductor 12 of the coaxial S-parameter phase standard 10. Within the frequency band DC to 26.5 GHz, the standard connector type is the APC-3.5mm connector. Based on relevant connector standards, determine the inner diameter of the outer conductor of the APC-3.5mm connector to be Φ. o_in =3.5mm, outer diameter Φ of inner conductor i_out =1.52mm.

[0052] Step S2: Determine the length of the coaxial S-parameter phase standard 10 by covering the phase change from -180° to +180° across the entire operating frequency band DC to 26.5GHz. Considering ease of fabrication and the concentricity between the inner conductor 12 and the outer conductor 11, determine the length of the APC-3.5mm connector to be 50mm.

[0053] Step S3: Calibrate the physical dimensions of the outer conductor 11 (inner diameter), inner conductor 12 (outer diameter), and length of the coaxial S-parameter phase standard 10 after machining. Measure the inner diameter Φ of the outer conductor. o_in Outer diameter Φ of the inner conductor i_out And length l.

[0054] Step S4: Calculate the phase shift value corresponding to each frequency within the operating frequency band, and set the phase shift value as the standard value corresponding to each frequency of the coaxial S-parameter phase standard 10.

[0055] Select the frequency point required for actual calibration; for example, 1GHz to 26GHz, with a frequency interval of 1GHz.

[0056] The wavelength corresponding to each frequency is calculated using the formula λ = c / f, with a frequency interval of 1 GHz. Therefore, the wavelengths corresponding to frequencies f are calculated as follows: 1 GHz, 2 GHz, 3 GHz, 4 GHz...26 GHz.

[0057] Using formula Calculate the phase shift corresponding to each frequency. Based on the wavelength values ​​corresponding to the frequencies mentioned above, calculate the phase shifts for 1 GHz, 2 GHz, 3 GHz, 4 GHz...26 GHz.

[0058] After that, the phase shifts corresponding to 1GHz, 2GHz, 3GHz, 4GHz...26GHz can be set to the standard values ​​corresponding to each frequency of the coaxial S-parameter phase standard 10.

[0059] Specifically, in order to prevent the inner conductor 12 from being too long, this application divides the inner conductor 12 into a first segment 121 and a second segment 122. The first segment 121 and the second segment 122 are fixedly connected to form the inner conductor 12. The first segment 121 is made of an elastic conductive material, and the second segment 122 is made of a rigid conductive material.

[0060] Furthermore, the first segment 121 of the inner conductor 12 is the female end, made of tin bronze and beryllium bronze, and the second segment 122 is the male end, made of brass or stainless steel.

[0061] In actual operation, if the inner conductor 12 is too long, the beryllium bronze or tin bronze is prone to bending, thus affecting the concentricity between the inner conductor 12 and the outer conductor 11. This application divides the inner conductor 12 into a first segment 121 and a second segment 122. This design solves the problem of beryllium bronze or tin bronze being prone to bending, and the structure is simple, easy to implement, and can greatly reduce costs.

[0062] Optionally, tin bronze and beryllium bronze are bronzes with tin and beryllium as the main alloying elements, respectively, and are mainly used to manufacture elastic elements and wear-resistant parts. In this embodiment, tin bronze and beryllium bronze are mainly used to make elastic elements. Tin bronze and beryllium bronze have very high elastic limits. Brass or stainless steel have high strength, high hardness, and strong wear resistance. When the female end of the inner conductor 12 is made of tin bronze and beryllium bronze, and the male end is made of brass or stainless steel, the voltage standing wave ratio of the female end of the inner conductor 12 and the concentricity between the inner conductor 12 and the outer conductor 11 are guaranteed, while the stability of the connection of the inner conductor 12 can also be improved.

[0063] From the above description, we can see that:

[0064] The design, implementation, and calibration method of the coaxial S-parameter phase standard of this application ensures that the medium between the inner conductor 12 and the outer conductor 11 of the coaxial S-parameter phase standard 10 is uniform and continuous. The theoretical value of the phase shift of the coaxial S-parameter phase standard can be calculated using the calibration value of the physical dimensions. This theoretical value is then used as the calibration value of the transmission phase to verify the measurement accuracy of the transmission phase of the vector network analyzer. This method allows the transmission phase standard to be traced back to its length, and its theoretical value of transmission phase can be determined through physical dimension calibration. The calibration result has high accuracy and is particularly suitable for use as the highest standard for transmission phase.

[0065] Furthermore, this application divides the inner conductor 12 into a first segment 121 and a second segment 122. The first segment 121 of the inner conductor 12 is the female end, made of tin bronze and beryllium bronze, while the second segment 122 is the male end, made of brass or stainless steel. This ensures the voltage standing wave ratio (VSWR) of the female end of the inner conductor 12 and the concentricity between the inner conductor 12 and the outer conductor 11, while also guaranteeing its technical specifications. The structure is simple, easy to implement, and low in cost.

[0066] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0067] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0068] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A calibration method for a coaxial S-parameter phase standard, characterized in that, The calibration method includes: Step S1: Determine the type of the coaxial S-parameter phase standard (10) according to the operating frequency band and determine the inner diameter of the outer conductor (11) and the outer diameter of the inner conductor (12) of the coaxial S-parameter phase standard (10). The inner conductor (12) includes a first segment (121) and a second segment (122). The first segment (121) and the second segment (122) are fixedly connected. The first segment (121) is made of an elastic conductive material, and the second segment (122) is made of a rigid conductive material. Step S2: Determine the length value corresponding to the phase change covering -180° to +180° within the entire operating frequency band as the length of the coaxial S-parameter phase standard (10); Step S3: Physically calibrate the inner diameter of the outer conductor (11), the outer diameter of the inner conductor (12), and the length of the coaxial S-parameter phase standard (10) after processing; Step S4: Calculate the phase shift value corresponding to each frequency in the working frequency band, and set the phase shift value as the standard value corresponding to each frequency of the coaxial S-parameter phase standard (10). The specific steps include: selecting the frequency point to be calibrated. Calculate the wavelength corresponding to each frequency based on the frequency point; calculate the phase shift value corresponding to each frequency.

2. The calibration method according to claim 1, characterized in that, In step S1, the operating frequency band DC is 18GHz and uses an N-type or APC-7mm connector, the operating frequency band DC is 26.5GHz and uses an APC-3.5mm connector, or the operating frequency band DC is 50GHz and uses an APC-2.4mm connector.

3. The calibration method according to claim 2, characterized in that, The inner diameter of the outer conductor (11) of the APC-3.5mm connector is Φ o_in The outer diameter of the inner conductor (12) is Φ i_out ,in Φ o_in 3.5mm 、 Φ i_out It is 1.52mm.

4. The calibration method according to claim 1, characterized in that, The wavelength is expressed by the formula λ=c / f Calculate, where, λ Wavelength, in meters; c The speed of light is measured in meters per second. f Frequency, measured in Hertz.

5. The calibration method according to claim 4, characterized in that, The phase shift value is expressed by the formula φ=2πl / λ Calculate, where, φ This is the phase shift value, in radians; l The length of the calibrated coaxial S-parameter phase standard (10) is in meters.

6. The calibration method according to claim 1, characterized in that, In step S2, the length of the coaxial S-parameter phase standard (10) is 20mm~55mm.

7. The calibration method according to claim 1, characterized in that, The elastic conductive material is beryllium bronze or tin bronze, and the rigid conductive material is brass or stainless steel.

8. The calibration method according to claim 1, characterized in that, The first segment (121) is located at the female end of the inner conductor (12), and the second segment (122) is located at the male end of the inner conductor (12).

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