Liquid crystal transmission line phase shifter

Abstract

The utility model discloses a liquid crystal transmission line phase shifter. The liquid crystal display comprises an upper layer substrate and a lower layer substrate, a liquid crystal layer is arranged between the upper layer substrate and the lower layer substrate, the liquid crystal layer comprises liquid crystal and orientation layers arranged on the upper side and the lower side of the liquid crystal, a metal ground with a defect structure and a microstrip line are arranged in the liquid crystal, and the defect structure comprises a plurality of dumbbell-shaped openings which are sequentially arranged at intervals. The microstrip line corresponds to the middle position of the dumbbell-shaped opening, the dumbbell-shaped opening comprises a plurality of first dumbbell-shaped openings formed in the middle and a plurality of second dumbbell-shaped openings formed in the two sides of the first dumbbell-shaped openings, and the size of the first dumbbell-shaped openings is larger than that of the second dumbbell-shaped openings; and the thickness of the second dumbbell-shaped opening is the same as that of the second dumbbell-shaped opening. According to the utility model, excellent impedance matching characteristics are obtained, low loss is ensured, the phase shift range is improved, the quality factor of the phase shifter is increased, the structure and the manufacturing process are simple, and the cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of phase shifters, and particularly relates to a liquid crystal transmission line phase shifter. Background Art

[0002] A phase shifter is a device that can adjust the phase of an electromagnetic wave and is widely used in fields such as radar and communication. Liquid crystal phase shifters have advantages in continuous tunability. As is well known, the electrical properties of liquid crystals depend on the molecular orientation, and the molecular orientation can be changed by the variation of an electric field generated by an applied voltage. By changing the voltage applied across the liquid crystal layer, the dielectric constant of the liquid crystal can be changed.

[0003] The commonly used liquid crystal phase shifter structure is a microstrip line with a liquid crystal layer as the substrate. This requires a thick liquid crystal substrate to achieve low loss. There are structures of thin liquid crystal-based transmission lines, but they require additional bias circuits or transitions for feeding, which will lead to complex manufacturing processes and potential cost increases. Achieving low loss and large phase shift in a liquid crystal phase shifter is a great challenge under the conditions of ensuring easy control and manufacturing. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a liquid crystal transmission line phase shifter aiming at the deficiencies existing in the prior art.

[0005] To achieve the above purpose, the utility model provides a liquid crystal transmission line phase shifter, which includes an upper substrate and a lower substrate. A liquid crystal layer is provided between the upper substrate and the lower substrate. The liquid crystal layer includes liquid crystal and alignment layers arranged on the upper and lower sides of the liquid crystal. A metal ground and a microstrip line with a defect structure are provided in the liquid crystal. The defect structure includes a plurality of dumbbell-shaped openings arranged at intervals in sequence. The microstrip line corresponds to the middle position of the dumbbell-shaped opening. The dumbbell-shaped opening includes a plurality of first dumbbell-shaped openings arranged in the middle and a plurality of second dumbbell-shaped openings arranged on both sides of the first dumbbell-shaped opening. The size of the first dumbbell-shaped opening is larger than that of the second dumbbell-shaped opening, and their thicknesses are the same.

[0006] Further, the dumbbell-shaped opening includes a rectangular opening transversely arranged in the middle and two square openings respectively arranged at both ends of the rectangular opening.

[0007] Further, the length of the rectangular opening of the first dumbbell-shaped opening is 0.09 mm, and its width is 0.03 mm. The side length of the square opening of the first dumbbell-shaped opening is 0.18 mm.

[0008] Further, the length of the rectangular opening of the second dumbbell-shaped opening is 0.1 mm, and its width is 0.03 mm. The side length of the square opening of the first dumbbell-shaped opening is 0.2 mm.

[0009] Further, the microstrip line includes a transmission line and a high-impedance feeder structure disposed at one end of the transmission line, and the widths of both ends of the transmission line are smaller than the width of the middle part.

[0010] Further, the widths of both ends of the microstrip line are 0.03 mm, and the width of the middle part is 0.1 mm.

[0011] Further, the high-impedance feeder structure includes a connection line perpendicular to the end of the transmission line and fan-shaped structures symmetrically disposed on both sides of the middle of the connection line.

[0012] Beneficial effects: By providing a defect structure formed by arranging the first dumbbell-shaped opening and the second dumbbell-shaped opening on the metal ground, and a high-impedance feeder structure on the microstrip line, the present utility model obtains excellent impedance matching characteristics, improves the phase shift range while ensuring low loss, increases the quality factor of the phase shifter, and has a simple structure and manufacturing process with low cost. Description of the Drawings

[0013] Figure 1 is a three-dimensional view of the liquid crystal transmission line phase shifter of the present utility model;

[0014] Figure 2 is a schematic structural view of the metal ground with a defect structure of the present utility model;

[0015] Figure 3 is a schematic view of the microstrip line of the present utility model;

[0016] Figure 4 is a schematic view of the high-impedance feeder structure on the microstrip line;

[0017] Figure 5 is an S-parameter diagram of the liquid crystal transmission line phase shifter of the present utility model;

[0018] Figure 6 is another S-parameter diagram of the liquid crystal transmission line phase shifter of the present utility model;

[0019] Figure 7 is a phase shift parameter diagram of the liquid crystal transmission line phase shifter of the present utility model. Detailed Embodiments

[0020] The following further clarifies the present utility model in conjunction with the drawings and specific embodiments. These embodiments are implemented on the premise of the technical solution of the present utility model, and it should be understood that these embodiments are only used to illustrate the present utility model and not to limit the scope of the present utility model.

[0021] Such as Figures 1 to 4As shown in the figure, an embodiment of the present invention provides a liquid crystal transmission line phase shifter, which includes an upper substrate 1 and a lower substrate 5. The upper substrate 1 and the lower substrate 2 can be glass plates. A liquid crystal layer 3 is provided between the upper substrate 1 and the lower substrate 5. Among them, the liquid crystal layer 3 can be specifically divided into liquid crystal and alignment layers provided on both the upper and lower sides of the liquid crystal. A metal ground 2 with a defect structure and a microstrip line 4 are provided in the liquid crystal. The metal ground 2 and the microstrip line 4 are respectively embedded on both the upper and lower sides of the liquid crystal, and the microstrip line 4 corresponds to the middle position of the dumbbell-shaped opening. The above defect structure includes a plurality of dumbbell-shaped openings arranged at intervals in sequence. The dumbbell-shaped openings can be divided into two types according to size. One is a plurality of first dumbbell-shaped openings provided in the middle, and the other is a plurality of second dumbbell-shaped openings provided on both sides of the first dumbbell-shaped openings. In the figure, there are 12 first dumbbells shown, and 12 second dumbbell openings on each side, for a total of 24. The size of the first dumbbell-shaped opening is larger than that of the second dumbbell-shaped opening, and their thicknesses are the same.

[0022] Specifically, the dumbbell-shaped opening includes a rectangular opening horizontally provided in the middle and two square openings respectively provided at both ends of the rectangular opening. As a preferred embodiment, the length of the rectangular opening 6 of the first dumbbell-shaped opening is 0.09 mm, and its width is 0.03 mm. The side length of the square opening 7 of the first dumbbell-shaped opening is 0.18 mm. The length of the rectangular opening 8 of the second dumbbell-shaped opening is 0.1 mm, and its width is 0.03 mm. The side length of the square opening 9 of the first dumbbell-shaped opening is 0.2 mm.

[0023] The microstrip line 4 in the embodiment of the present invention includes a transmission line 41 and a high-impedance feeder structure 42 provided at one end of the transmission line 41. Among them, the widths of both ends of the transmission line 41 are smaller than the width of the middle part. As a preferred embodiment, the width of both ends of the microstrip line 4 is 0.03 mm, and the width of the middle part of the microstrip line 4 is 0.1 mm. The above high-impedance feeder structure 42 is used to load a DC bias voltage while ensuring that the RF signal does not enter the DC feeding network through this structure. The high-impedance feeder structure 42 specifically includes a connection line 421 perpendicular to the end of the transmission line 41 and fan-shaped structures 422 symmetrically provided on both sides of the middle of the connection line 421.

[0024] See Figure 5 - to Figure 7 :

[0025] Figure 5Details the relationship between frequency (GHz) and S11 value (dB) at different epsilon values (2.35, 2.975, 3.6). In the graph, three distinct curves correspond to these three epsilon values, showing their influence on the variation of S11 value with frequency. Squares and lines depict the trend of S11 value changing with frequency from 30 GHz to 40 GHz when epsilon = 2.35, showing relatively gentle fluctuations. Dots and lines represent the case of epsilon = 2.975, where its S11 value increases at some frequency points compared to epsilon = 2.35, indicating that as the epsilon value increases, the amplitude of the spectrogram also increases at some frequency points. Triangles and lines show the case of epsilon = 3.6, where the change in its S11 value is more significant, especially in the high-frequency range, showing a higher amplitude, further verifying the influence of the epsilon value on the spectral characteristics.

[0026] Figure 6 The spectrogram details the variation of signal intensity at different epsilon values (2.35, 2.975, and 3.6) within the frequency range of 30 GHz to 40 GHz. In the figure, the horizontal axis represents frequency in GHz, and the vertical axis represents signal intensity in dB. Three curves correspond to different epsilon values: the square line represents epsilon = 2.35, the circle line represents epsilon = 2.975, and the triangle line represents epsilon = 3.6. As the frequency increases, all curves show a trend of gradually decreasing signal intensity, but the degree of fluctuation of each curve at different frequency points is different. There are significant differences in the signal intensity of curves with different epsilon values at the same frequency.

[0027] Figure 7 Shows the trend of the phase difference changing with frequency at different epsilon values (2.35, 2.975, 3.6). The horizontal axis represents frequency, ranging from 30 GHz to 40 GHz in GHz; the vertical axis represents the phase difference, ranging from -180 degrees to 180 degrees in degrees. In the graph, three curves correspond to different epsilon values: the curve marked with squares corresponds to epsilon = 2.35, the curve marked with dots corresponds to epsilon = 2.975, and the curve marked with triangles corresponds to epsilon = 3.6. As the frequency increases, the phase difference of all curves shows a trend of gradually decreasing, but the slopes of the curves under different epsilon values are different, reflecting different phase characteristics.

[0028] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, the parts not specifically described belong to the prior art or common general knowledge. Without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. A liquid crystal transmission line phase shifter, comprising an upper substrate and a lower substrate, characterized in that: A liquid crystal layer is arranged between the upper substrate and the lower substrate, the liquid crystal layer includes liquid crystal and alignment layers arranged on the upper and lower sides of the liquid crystal, a metal ground and a microstrip line with a defect structure are arranged in the liquid crystal, the defect structure includes a plurality of dumbbell-shaped openings arranged in sequence, the microstrip line corresponds to the middle position of the dumbbell-shaped opening, the dumbbell-shaped opening includes a plurality of first dumbbell-shaped openings arranged in the middle and a plurality of second dumbbell-shaped openings arranged on both sides of the first dumbbell-shaped opening, the size of the first dumbbell-shaped opening is larger than the size of the second dumbbell-shaped opening, and the first dumbbell-shaped opening has the same thickness as the second dumbbell-shaped opening.

2. A liquid crystal transmission line phase shifter according to claim 1, characterized in that: The dumbbell-shaped opening comprises a rectangular opening arranged transversely in the middle and two square openings arranged at two ends of the rectangular opening respectively.

3. A liquid crystal transmission line phase shifter according to claim 2, characterized in that: The length of the rectangular opening of the first dumbbell-shaped opening is 0.09 mm, and the width thereof is 0.03 mm, and the side length of the square opening of the first dumbbell-shaped opening is 0.18 mm.

4. The liquid crystal transmission line phase shifter according to claim 3, characterized in that: The length of the rectangular opening of the second dumbbell-shaped opening is 0.1 mm and the width is 0.03 mm, and the side length of the square opening of the first dumbbell-shaped opening is 0.2 mm.

5. The liquid crystal transmission line phase shifter according to claim 1, characterized in that: The microstrip line comprises a transmission line and a high-resistance feeder structure arranged at one end of the transmission line, and the width of the two ends of the transmission line is smaller than the width of the middle part.

6. The liquid crystal transmission line phase shifter according to claim 5, characterized in that: The width of the microstrip line at both ends is 0.03 mm, and the width of the middle portion is 0.1 mm.

7. The liquid crystal transmission line phase shifter according to claim 5, characterized in that: The high-resistance feeder structure comprises a connecting line perpendicular to the end of the transmission line and a fan-shaped structure symmetrically arranged on both sides of the middle of the connecting line.

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