Implementation method for converting differential line into microstrip line and microwave transmission line

Abstract

The invention discloses an implementation method for converting a differential line into a microstrip line and a microwave transmission line. Two signal input ends and a signal output end are arranged on the microstrip line; the two signal input ends are respectively a first input end and a second input end; a first input signal is input from the first input end, and a second input signal is input from the second input end; the phase difference phi between the phase phi 1 of the first input signal and the phase phi 1 of the second input signal is 180 degrees; the distance difference d between the first input end and the signal output end and between the second input end and the signal output end is half wavelength. The implementation method for converting the differential line into the microstrip line and the microwave transmission line have the advantages of being high in anti-interference capacity, capable of reducing electromagnetic radiation, good in signal integrity, capable of adapting to high-speed transmission and the like.

Description

Technical Field

[0001] The present invention relates to a microwave transmission technology, in particular to a method for converting a differential line to a microstrip line and a microwave transmission line. Background Art

[0002] Single-ended signals are relative to differential signals. Single-ended input refers to a signal consisting of a reference end and a signal end, with the reference end generally being the ground end. The technical disadvantages of single-ended signals are as follows: (1) Noise sensitivity: Traditional single-ended signals use the ground as a reference and are susceptible to power supply noise and external electromagnetic interference (EMI); (2) Radiation issues: The high-frequency components of single-ended signals generate strong electromagnetic radiation, making it difficult to meet EMC standards; (3) Speed ​​bottleneck: As the frequency increases, the signal edge becomes steeper, reflections and crosstalk intensify, and signal integrity deteriorates. Due to the limitations of single-ended signals, differential signals were proposed.

[0003] Differential transmission is a signal transmission technology that differs from the traditional practice of using one signal line and one ground line (single-ended signaling). Differential transmission uses two lines to transmit signals with equal amplitudes and opposite phases. The signal transmitted over these two lines is called a differential signal. A differential line is two coupled, parallel transmission lines of equal length that transmit signals with a 180-degree phase difference. Differential lines transmit signals over two lines with opposite phases, using differential detection to cancel common-mode noise and overcome the limitations of single-ended signaling.

[0004] A microstrip line is a microwave transmission line consisting of a single conductor strip supported on a dielectric substrate, with a grounded metal plate on the other side of the substrate. Microstrip lines are usually used for single-ended signal transmission. In the process of converting differential lines to microstrip lines, there are often the following problems: (1) Impedance matching: The conventional impedance value of a microstrip line is 50Ω, while the impedance of a differential line is usually around 90Ω. During the design process, it is necessary to ensure a smooth transition between the impedances of the two to avoid signal reflection and distortion; (2) Structural design: The structural design of the microstrip to microstrip differential line involves the design of the width, thickness, material, and ground layer of the microstrip line. Parameters such as the spacing and length of the differential signal lines also need to be considered; (3) Signal integrity: In high-speed signal transmission, issues such as signal delay, distortion, and phase difference require special attention.

[0005] Microwave transmission lines are generally designed based on microstrip lines, so it is urgent to design a method to convert differential lines to microstrip lines to solve the problem of single-ended signal limitations. Summary of the Invention

[0006] The present invention aims to overcome the deficiencies in the above-mentioned prior art and provides a method for converting a differential line to a microstrip line and a microwave transmission line, so as to reduce return loss and insertion loss during microwave transmission.

[0007] The present invention adopts the following technical solutions to solve the technical problems.

[0008] A method for converting a differential line to a microstrip line of the present invention is provided with two signal input terminals and a signal output terminal 1; the two signal input terminals are respectively a first input terminal 2 and a second input terminal 3; a first input signal is input by the first input terminal, and a second input signal is input by the second input terminal; a phase difference Δφ between a phase φ1 of the first input signal and a phase φ2 of the second input signal is 180°; and a distance difference Δd between the first input terminal and the second input terminal to the signal output terminal is half a wavelength.

[0009] The present invention also discloses a microwave transmission line for realizing the method of converting a differential line to a microstrip line, comprising a U-shaped body; two terminals at the opening of the U-shaped body serve as two signal input ends.

[0010] The structural characteristics of the method for converting a differential line to a microstrip line of the present invention are also as follows: Furthermore, a signal output terminal 1 is provided on a side of the U-shaped body away from the opening.

[0011] Furthermore, metal grounding holes and metal reference grounds are provided around the two signal input terminals.

[0012] Furthermore, the end of the signal output terminal 1 adopts a balun gradient form.

[0013] Compared with the existing technology, the beneficial effects of the present invention are embodied in: The present invention discloses a method for converting a differential line to a microstrip line. Two signal input terminals and one signal output terminal are provided on the microstrip line. The two signal input terminals are respectively a first input terminal and a second input terminal. A first input signal is inputted by the first input terminal, and a second input signal is inputted by the second input terminal. The phase difference Δφ between the phase φ1 of the first input signal and the phase φ1 of the second input signal is 180°. The distance difference Δd between the first input terminal and the second input terminal to the signal output terminal is half a wavelength.

[0014] The method for converting a differential line to a microstrip line and the microwave transmission line of the present invention have the advantages of strong anti-interference capability, reduced electromagnetic radiation, good signal integrity, and adaptability to high-speed transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a schematic diagram of a microwave transmission line in one embodiment of a method for converting a differential line to a microstrip line according to the present invention.

[0016] Figure 2 is Figure 1Schematic diagram of adding metal ground holes and metal reference ground around the differential line structure and microstrip line structure of the microwave transmission line.

[0017] Figure 3 yes Figure 2 Schematic diagram of a microwave transmission line with a microstrip structure where the width at the end is tapered using a balun.

[0018] Figure 4 A second embodiment of the microwave transmission line.

[0019] Figure 5 is Figure 4 Schematic diagram of adding metal grounding holes around the differential line structure and microstrip line structure of the microwave transmission line.

[0020] Figure 6 is Figure 4 Schematic diagram of adding metal ground holes and metal reference ground around the differential line structure and microstrip line structure of the microwave transmission line.

[0021] Figure 7 This is a return loss curve of the differential line structure of the microwave transmission line of the present invention.

[0022] Figure 8 This is a return loss curve of the microstrip line structure of the microwave transmission line of the present invention.

[0023] Figure 9 This is the insertion loss curve of the microwave transmission line of the present invention.

[0024] The present invention will be further described below through specific implementation methods in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0025] See also Figures 1 to 9 A method for converting a differential line to a microstrip line of the present invention is provided with two signal input terminals and a signal output terminal 1; the two signal input terminals are respectively a first input terminal 2 and a second input terminal 3; a first input signal is inputted by the first input terminal, and a second input signal is inputted by the second input terminal; a phase difference Δφ between a phase φ1 of the first input signal and a phase φ2 of the second input signal is 180°; and a distance difference Δd between the first input terminal and the second input terminal to the signal output terminal is half a wavelength.

[0026] The method for converting a differential line to a microstrip line of the present invention can convert the differential line to a microstrip line, and then transmit the signal output by the chip to a single-ended microstrip line. The wavelengths of the two input signals at the two signal input ends are both λ, and the phases of the two input signals are φ1 and φ2, respectively. The phase difference between the two input signals is 180°, that is, △φ=︱φ1-φ2︱=180°. The distance difference △d from the two signal input ends to the signal output end of the single-ended microstrip line is half the wavelength λ of the input signal, that is, △d=λ / 2. This just ensures that the two input signals at the two signal input ends are in phase when transmitted to the signal output end of the microstrip line.

[0027] The present invention also discloses a microwave transmission line for realizing the method of converting a differential line to a microstrip line, comprising a U-shaped body; two terminals at the opening of the U-shaped body serve as two signal input ends.

[0028] During specific implementation, a side of the U-shaped body away from the opening is set as the signal output end 1.

[0029] In a specific implementation, metal grounding holes and metal reference grounds are provided around the two signal input terminals.

[0030] During specific implementation, the end of the signal output terminal 1 adopts a balun gradient form.

[0031] like Figure 1 In a first embodiment of the microwave transmission line, the U-shaped body portion is a differential line structure and includes two signal input terminals; Below the U-shaped body is a microstrip line structure including a signal output end. Figure 1 This microwave transmission line is suitable for most differential line-to-microstrip line applications and has good versatility. The width of the left portion of the signal input terminal is smaller than that of the rightmost end. The left portion of the signal input terminal is recessed inward to reduce the width.

[0032] like Figure 2 is Figure 1 Metal grounding holes and metal reference grounds are added around the differential line structure and microstrip line structure of the microwave transmission line. Such a structure can improve the isolation between multiple differential line to microstrip line structures.

[0033] like Figure 3 yes Figure 2 The width of the end of the microstrip line structure of the microwave transmission line adopts a balun gradient to better match and adjust. Starting from the first position away from the differential line structure, the width W1 of the microstrip line structure gradually decreases to the width W2. Starting from the second position, the width W2 remains unchanged until the end.

[0034] like Figure 4The second embodiment of the microwave transmission line is Figure 1 The structure is deformed based on the structure of the upper two signal input terminals are L-shaped structure, this shape is better than Figure 1 The structure is easier to process and reduces production costs. A notch is provided on the outer side of the right end of the signal input terminal. The width of the signal input terminal becomes smaller at the first position after extending from right to left.

[0035] like Figure 5 is Figure 4 Metal grounding holes are added around the differential line structure and microstrip line structure of the microwave transmission line. This structure can improve the isolation between multiple differential line to microstrip line structures.

[0036] like Figure 6 is Figure 4 Metal grounding holes and metal reference grounds are added around the differential line structure and microstrip line structure of the microwave transmission line. Such a structure can improve the isolation between multiple differential line to microstrip line structures.

[0037] The method for converting a differential line to a microstrip line and the microwave transmission line of the present invention have the following characteristics: 1. Strong anti-interference ability: common mode noise suppression, suitable for noisy environments (such as near motors and wireless devices); 2. Reduce electromagnetic radiation (EMI): The currents in the two wires are in opposite directions, and the magnetic fields generated cancel each other out, reducing the electromagnetic interference radiated to the outside. 3. Higher signal integrity: better timing control and reduced ground reference dependence; 4. Adapt to high-speed transmission: Under high-frequency signals, the impedance matching of differential pairs is easier to control, reducing reflections and signal distortion.

[0038] The present invention utilizes the design of converting differential lines to microstrip lines, which can not only take advantage of the advantages of differential lines in terms of strong anti-interference ability, reduced electromagnetic radiation, and higher signal integrity, but also take into account the existing technical solutions using microstrip lines to improve product performance.

[0039] Figure 7 This is the return loss curve of the differential line structure of the microwave transmission line of the present invention during the experiment. Figure 2 It can be seen from the figure that the differential line structure of the microwave transmission line of the present invention has an overall return loss of less than -14dB in the 70GHz-90GHz frequency band, and has excellent performance.

[0040] Figure 8 This is the return loss curve of the microstrip line structure of the microwave transmission line of the present invention during the experiment. Figure 3It can be seen from the figure that the return loss of the microstrip line structure of the microwave transmission line of the present invention in the frequency band of 70 GHz to 90 GHz is below -15 dB as a whole, and the performance is excellent.

[0041] Figure 9 This is the insertion loss curve of the microwave transmission line of the present invention during the experiment. Figure 4 It can be seen from the figure that the insertion loss of the microwave transmission line of the present invention in the frequency band of 70 GHz to 90 GHz is within 0.6 dB as a whole, and the insertion loss is very small.

[0042] In the present invention, the signal from the external chip is output to the differential line structure of the microwave transmission line (i.e., the two signal input ends) in the form of a differential line, and then the signal is transmitted to the microstrip line structure of the transmission line (i.e., the signal output end) by converting the differential line to a microstrip line. The single-ended microstrip line then transmits the signal to an antenna or other device.

[0043] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0044] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for converting a differential line to a microstrip line, characterized in that: Two signal input terminals and a signal output terminal (1) are provided; the two signal input terminals are respectively a first input terminal (2) and a second input terminal (3); a first input signal is inputted from the first input terminal, and a second input signal is inputted from the second input terminal; a phase difference Δφ between a phase φ1 of the first input signal and a phase φ2 of the second input signal is 180°; and a distance difference Δd between the first input terminal and the second input terminal to the signal output terminal is half a wavelength.

2. A microwave transmission line for implementing the differential line to microstrip line conversion method according to claim 1, characterized in that: It comprises a U-shaped body; two terminals at the opening of the U-shaped body serve as two signal input terminals.

3. The microwave transmission line according to claim 2, wherein: A signal output end (1) is provided on one side of the U-shaped body away from the opening.

4. The microwave transmission line according to claim 2, wherein: Metal grounding holes and metal reference grounds are arranged around the two signal input terminals.

5. The microwave transmission line according to claim 2, wherein: The end of the signal output terminal (1) adopts a balun gradient form.

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