Convenient equal-phase design method in radio frequency multilayer wiring

Abstract

The invention discloses a convenient equal-phase design method in radio frequency multilayer wiring, and proposes that under the condition that the dielectric constant of a transmission medium is fixed, equal-phase line lengths of different transmission line structures are obtained directly through fixed value proportion calculation and conversion, so that equal-phase line arrangement is completed. According to the conventional isophase line design, the absolute value of the electrical length needs to be calculated according to the transmission frequency, the transmission medium and the transmission line structure, the absolute value of the electrical length needs to be calculated again as long as one of a reference transmission line and a target transmission line changes the transmission line structure, the work is quite complicated for multi-layer radio frequency wiring with various paths, and the design cost is low. When the method is applied to the convenient design of multilayer equal-phase wiring, the wire length proportion obtained through initial calculation is directly converted, a large amount of simulation calculation of subsequent wiring can be omitted, the design research and development process is simplified, and the method is suitable for multilayer and broadband radio frequency wiring design engineering of a multilayer board, a ceramic substrate and the like.

Description

Technical Field

[0001] The present invention relates to a convenient isophase design method in radio frequency multilayer wiring, which is applicable to multilayer radio frequency isophase wiring design projects of multilayer boards, ceramic substrates and the like. Background Art

[0002] With the development of microwave miniaturized integrated circuits and the increasing demand for equal amplitude and same phase of phased array components, in many cases, equal phase routing design must be used in RF multi-layer wiring projects. However, due to the restrictions on the arrangement position and the influence of avoidance devices, designers often need to transition the RF signal line to the middle layer and then perform equal phase design. However, the difficulty lies in that this process changes the transmission structure, from microstrip line to stripline, or microstrip line to coaxial line, or stripline to coplanar waveguide, which requires engineers to simulate and confirm the design of each section of equal phase line, which is a huge workload. Starting from theoretical research, the present invention can directly calculate and convert the equal phase line length ratio under different transmission structures by directly calculating and converting the substrate dielectric constant medium under the condition that the transmission structure is determined through a fixed value ratio. The design and development process is simplified.

[0003] Existing literature reports on the requirements for equal phase transmission:

[0004] Reference 1 (Research on Millimeter Wave MIMO RF Channel Consistency, 2019 Master's Thesis);

[0005] Reference 2 (Research on the consistency of transceiver channels of digital array radar components. Modern Radar, 2020);

[0006] Reference 3 (Research on key technologies of millimeter wave phased array, 2016 master's thesis)

[0007] Reference 1 combines the required beam pointing and phase calibration algorithm to perform phase calibration. Reference 2 reduces the number of modules and interconnections of components through integrated design, and achieves better amplitude and phase consistency through digital compensation.

[0008] Reference 3 uses high-precision and high-stability LTCC processing technology to ensure good phase consistency of components.

[0009] Most of the reported literatures use process guarantee or external compensation to achieve phase consistency requirements. The solution of the present invention uses theoretical derivation to provide a convenient equal-phase design method under different paths and different transmission structures in the design process. The idea is different from that of the reported literatures, and no directly related literature has been found. Summary of the invention

[0010] The technical problem solved by the present invention is: in order to overcome the problem of complex equal-phase design calculation under different transmission structures of radio frequency lines in multilayer board wiring, a method for calculating the length ratio under equal phase for transmission lines under different structures based on a theoretical algorithm is proposed under the premise that the dielectric constant remains unchanged and the transmission structure is determined.

[0011] The technical solution to achieve the purpose of the present invention is: a convenient equal-phase design method in RF multi-layer wiring, which is used for equal-phase conversion between strip lines, microstrip lines, coplanar waveguides, grounded coplanar waveguides, coaxial lines, quasi-coaxial lines, and substrate-integrated coaxial lines under the same medium transmission conditions of a 50 ohm transmission system. The steps are as follows:

[0012] Determine the baseline that needs to be equalized, measure and record the path lengths of different transmission structures, and calculate the path length of the bend line using the center point of the transmission line width;

[0013] According to electromagnetic field theory, the ratio of the length of the isophase line to the reference line under different transmission structures is calculated;

[0014] Multiply the baseline length by the ratio of the equal phase line to the baseline length to obtain the target line length and complete the wiring.

[0015] Furthermore, according to the electromagnetic field theory, the ratio of the length of the isophase line to the reference line under different transmission structures is calculated, and the steps are as follows:

[0016] It is known from electromagnetic theory that the transmission of stripline is TEM mode, and the corresponding wavelength is Where λ0 is the free space wavelength, ε r is the relative dielectric constant of the transmission medium of the electromagnetic wave, β 带线 is the stripline phase constant; the transmission of coaxial line, quasi-coaxial line and substrate integrated coaxial line are all TEM mode, and the corresponding wavelength is therefore, That is, coaxial line, quasi-coaxial line, stripline, substrate integrated coaxial line, equal length and phase under the same dielectric constant;

[0017] It is known from electromagnetic theory that the transmission mode of microstrip line is quasi-TEM mode, and the corresponding waveguide wavelength λ g微带 for where ε e微带 is the equivalent dielectric constant of the microstrip line, 1<ε e微带 <ε r , Where c1 is the capacitance per unit length of the microstrip line, The capacitance per unit length of the air microstrip line is when the dielectric substrate is replaced by air. Under the conditions of transmission medium and structure,

[0018] It is known from electromagnetic theory that the transmission mode of coplanar waveguide and grounded coplanar waveguide is quasi-TEM mode, and the corresponding phase constant is The equivalent dielectric constant ε e共面波导 Different from the calculation of microstrip line, Where k = S / (S+2W), W is the width of the transmission conductor, h is the thickness of the medium, S is the distance between conductors, and k0 is the propagation constant. Under the conditions of transmission medium and structure, the length of the coaxial line or strip line with equal phase is:

[0019] Furthermore, the reference line length is multiplied by the ratio of the equal phase line to the reference line length to obtain the target line length, and the wiring is completed in the following steps:

[0020] The structural requirements of the root routing path arrangement are determined, and the transmission structure of the target equal-phase line is confirmed. The length ratio of the target transmission line that needs equal-phase conversion to the reference transmission line is set to A. 1 , A 2 .....A n , n is the number of structures of the benchmark transmission line, then the final designed target isophase line satisfies:

[0021] L1′+L2′+...+L n ′=A 1 L1+A 2 L2+...+A n L n

[0022] Among them, L1, L2...L n are the lengths of different transmission structure segments of the reference transmission line. The reference transmission line consists of n transmission structures, so the reference transmission line is divided into n segments for calculation, L0′, L1′.....L n ′ are the lengths of each target transmission line.

[0023] A convenient equal-phase design system in radio frequency multi-layer wiring implements the convenient equal-phase design method in radio frequency multi-layer wiring to achieve convenient equal-phase design in radio frequency multi-layer wiring.

[0024] Compared with the prior art, the present invention has the following significant advantages: it provides a direct theoretical basis for the design of equiphase lines under different transmission structures, simplifies the design process compared with the traditional simulation test method, and under the condition that the dielectric constant remains unchanged and the transmission structure is determined, the equiphase lines of different transmission structures grow into a linear proportional relationship, which provides a convenient method for the design of equiphase lines of RF line transmission wiring in multi-layer board wiring. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1The schematic diagram of the isophase transmission line pair can be calculated to scale with the reference transmission line.

[0026] Figure 2 Schematic diagram of transition transmission.

[0027] Figure 3 Schematic diagram of the coplanar waveguide structure.

[0028] Figure 4 Schematic diagram for modeling isophase verification of grounded coplanar waveguide and quasi-coaxial.

[0029] Figure 5 This is a sample phase simulation confirmation diagram.

[0030] Figure 6 Flowchart of a convenient equal-phase design method for RF multilayer wiring. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] The present invention provides a convenient design method based on microwave transmission theory formula for the mutual isophase conversion between stripline, microstrip, coplanar waveguide, grounded coplanar waveguide, coaxial line, quasi-coaxial line, and substrate integrated coaxial line transmission structures. The design method is specifically used for 50 ohm transmission systems, and compares the isophase line design after the baseline line conversion structure under the same medium transmission conditions (the dielectric constant of the medium is the same).

[0033] A convenient equal-phase design method in RF multi-layer wiring, the steps are as follows:

[0034] Step 1: Determine the baseline that needs to be equalized, measure and record the path lengths of different transmission structures. The path length of the bend line is calculated based on the center point of the transmission line width, which is convenient for the next step to calculate separately.

[0035] Step 2: Calculate the length ratio of the equiphase line to the reference line under different transmission structures based on electromagnetic field theory. Under fixed transmission medium and transmission structure, this ratio is a constant.

[0036] (1) Stripline and coaxial line, quasi-coaxial line or substrate integrated coaxial line

[0037] The transmission of the stripline is TEM mode, and the wavelength of the stripline is λ0 is the free space wavelength, ε r is the relative dielectric constant of the transmission medium of the electromagnetic wave, β 带线 is the stripline phase constant.

[0038] It is known from electromagnetic theory that the transmission of coaxial line, quasi-coaxial line and substrate integrated coaxial line are all TEM mode, and their wavelength is λ0 is the free space wavelength, ε r is the relative dielectric constant of the medium.

[0039] It can be inferred that

[0040]

[0041] Therefore, coaxial line, quasi-coaxial line, stripline, and substrate-integrated coaxial line have the same length and phase under the same dielectric constant.

[0042] (2) Coaxial line, quasi-coaxial line, stripline or substrate integrated coaxial line and microstrip line

[0043] It is known from electromagnetic theory that the transmission mode of microstrip line is quasi-TEM mode, and the waveguide wavelength of microstrip line is λ g微带 for 1<ε e微带 <ε r , Where C1 is the capacitance per unit length of the microstrip line, The unit length capacitance of the air microstrip line when the dielectric substrate is replaced by air, under the conditions of transmission medium and structure, ε e微带 is the equivalent dielectric constant. λ0 is the free space wavelength.

[0044] It can be inferred that

[0045]

[0046] Therefore, in a 50 ohm transmission system, under the condition that the transmission medium remains unchanged, this ratio is a constant.

[0047] (3) Coplanar waveguide or grounded coplanar waveguide and coaxial line, quasi-coaxial line, stripline or substrate integrated coaxial line

[0048] It is known from electromagnetic theory that the transmission mode of coplanar waveguide and grounded coplanar waveguide is quasi-TEM mode, and the corresponding phase constant is But its equivalent dielectric constant ε e共面波导 The calculation is different from that of microstrip line;

[0049]

[0050] Where k = S / (S+2W) The corresponding structural relationship of W, h, and S is shown in Figure 3 W is the width of the transmission conductor, h is the dielectric thickness, S is the distance between conductors, and k0 is the propagation constant.

[0051] It can be deduced that under the condition that the dielectric constant of the medium and the transmission structure are fixed:

[0052] Length of coaxial lines or strip lines of equal phase:

[0053] Therefore, in a 50 ohm transmission system, under the premise that W, h, and S of the coplanar waveguide in the same medium are constant, the length ratio of the coaxial line and the coplanar waveguide of equal phase is

[0054] Step 3: The target line length is equal to the measured baseline line length multiplied by a fixed ratio, and the wiring is done based on this length as needed.

[0055] According to the structural requirements of the actual routing path arrangement, the transmission structure of the target equal-phase line is determined. Assume that the length ratio of the target transmission line that needs equal-phase conversion in each section to the reference transmission line is A. 1 , A 2 .....A n , n is the number of structures of the benchmark transmission line, then the final designed target isophase line satisfies:

[0056] L1′+L2′+...+L n ′=A 1 L1+A 2 L2+...+A n L n

[0057] L1, L2...L n are the lengths of different transmission structure segments of the reference transmission line. The reference transmission line consists of n transmission structures, so the reference transmission line is divided into n segments for calculation, L0′, L1′.....L n ′ are the lengths of each target transmission line.

[0058] Example

[0059] In order to verify the effectiveness of the solution of the present invention, the following experimental design was performed.

[0060] Figure 2 Baseline infrastructure, Figure 4 For the equiphase conversion target, the transmission structures included in the baseline are: quasi-coaxial, grounded coplanar waveguide, substrate integrated coaxial line; the equiphase line to be laid out is the grounded coplanar waveguide.

[0061] According to the process method of the present invention, first, the use conditions are confirmed that the design environment for applying the convenient equal phase conversion method is a 50 ohm transmission system, the dielectric constant of the multilayer boards is consistent with 2.94, and the dielectric board is SJ9294 of Shengyi Technology. Then, the baseline length of each section structure is measured and recorded, and the path length of the bending line part is calculated based on the center point of the transmission line width.

[0062] Quasi-coaxial: 1.77mm×2=3.54mm;

[0063] Grounded coplanar waveguide: 5mm×2=10mm;

[0064] Substrate integrated coaxial line: 9.76mm.

[0065] Next, the isophase line length ratio between the target line transmission structure and the baseline line transmission structure is calculated.

[0066]

[0067] Finally, the target isophase line length is calculated,

[0068] The length of the grounded coplanar waveguide line = 1.18×3.54mm+1.18×9.76mm+10mm=25.7mm.

[0069] Figure 5 This is the calculation result of the phase difference of the transmission line in the passive simulation software. It can be seen that the equiphase line calculated according to the ratio of the method of the present invention has a good phase consistency. The method of the present invention is suitable for multi-layer RF wiring design projects such as multi-layer boards and ceramic substrates. It can be widely used in equiphase design in RF multi-layer wiring and promoted among designers.

[0070] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A convenient equal-phase design method in radio frequency multilayer wiring, characterized in that: It is used for equal phase conversion between stripline, microstrip line, coplanar waveguide, grounded coplanar waveguide, coaxial line, quasi-coaxial line and substrate integrated coaxial line in 50 ohm transmission system with the same medium transmission conditions. The steps are as follows: Determine the baseline that needs to be equalized, measure and record the path lengths of different transmission structures, and calculate the path length of the bend line using the center point of the transmission line width; According to electromagnetic field theory, the ratio of the length of the isophase line to the reference line under different transmission structures is calculated; Multiply the baseline length by the ratio of the equal phase line to the baseline length to obtain the target line length and complete the wiring.

2. The convenient equal-phase design method in radio frequency multi-layer wiring according to claim 1, characterized in that: According to the electromagnetic field theory, the ratio of the length of the isophase line to the reference line under different transmission structures is calculated, where: It is known from electromagnetic theory that the transmission of stripline is TEM mode, and the corresponding wavelength is Where λ0 is the free space wavelength, ε r is the relative dielectric constant of the transmission medium of the electromagnetic wave, β 带线 is the stripline phase constant; the transmission of coaxial line, quasi-coaxial line and substrate integrated coaxial line are all TEM mode, and the corresponding wavelength is therefore, That is, coaxial line, quasi-coaxial line, strip line, substrate integrated coaxial line, with equal length and phase under the same dielectric constant.

3. The convenient equal-phase design method in radio frequency multi-layer wiring according to claim 1, characterized in that: According to the electromagnetic field theory, the ratio of the length of the isophase line to the reference line under different transmission structures is calculated, where: It is known from electromagnetic theory that the transmission mode of microstrip line is quasi-TEM mode, and the corresponding waveguide wavelength λ g微带 for where ε e微带 is the equivalent dielectric constant of the microstrip line, 1<ε e微带 <ε r , Where C1 is the capacitance per unit length of the microstrip line, The capacitance per unit length of the air microstrip line is when the dielectric substrate is replaced by air. Under the conditions of transmission medium and structure, 4. The convenient equal-phase design method in radio frequency multi-layer wiring according to claim 1, characterized in that: According to the electromagnetic field theory, the ratio of the length of the isophase line to the reference line under different transmission structures is calculated, where: It is known from electromagnetic theory that the transmission mode of coplanar waveguide and grounded coplanar waveguide is quasi-TEM mode, and the corresponding phase constant is The equivalent dielectric constant ε e共面波导 Different from the calculation of microstrip line, Where k = S / (S+2W), W is the width of the transmission conductor, h is the thickness of the medium, S is the distance between conductors, and k0 is the propagation constant. Under the conditions of transmission medium and structure, the length of the coaxial line or strip line with equal phase is:

5. The convenient equal-phase design method in radio frequency multi-layer wiring according to claim 1, characterized in that: The above-mentioned steps of multiplying the baseline length by the ratio of the equal phase line to the baseline length to obtain the target line length and completing the wiring are as follows: The structural requirements of the root routing path arrangement are determined, and the transmission structure of the target equal-phase line is confirmed. The length ratio of the target transmission line that needs equal-phase conversion to the reference transmission line is set to A. 1 , A 2 .....A n , n is the number of structures of the benchmark transmission line, then the final designed target isophase line satisfies: L′1+L′2+...+L′ n =A 1 L1+A 2 L2+...+A n L n Among them, L1, L2...L n are the lengths of different transmission structure segments of the reference transmission line. The reference transmission line consists of n transmission structures, so the reference transmission line is divided into n segments for calculation, L′0, L′1.....L′ n are the target transmission line lengths of each section respectively.

6. A convenient isophase design system in RF multilayer wiring, characterized in that: Implement the convenient equal-phase design method in radio frequency multi-layer wiring as described in any one of claims 1 to 5 to achieve convenient equal-phase design in radio frequency multi-layer wiring.

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