Modulation unit and method for manufacturing the same, modulation device and driving method thereof

Abstract

Modulation unit (20) and preparation method thereof, modulation device and driving method thereof relate to microwave and wireless communication technology field.Modulation unit (20) includes: bottom plate (10), bottom plate (10) includes substrate (11), and metal layer (12) is arranged on one side of substrate (11), and metal layer (12) has slit (13) on it;And driving layer (14), driving layer (14) is arranged on one side of bottom plate (10), and driving layer (14) includes pole plate (15) and driving structure (16), and gap (hl) exists between pole plate (15) and bottom plate (10);Modulation unit (20) includes at least one resonant structure (21), resonant structure (21) includes: slit (13), pole plate (15) and driving structure (16);In the same resonant structure (21), driving structure (16) is connected with pole plate (15), for responding to driving signal, driving pole plate (15) moves, to change the size of the overlapping area of the orthographic projection of pole plate (15) on bottom plate (10) and slit (13), adjusts the resonant frequency of resonant structure (21).

Description

Technical Field

[0001] This disclosure relates to the field of microwave and wireless communication technology, and in particular to a modulation unit and its fabrication method, a modulation device and its driving method. Background Technology

[0002] Since 2014, digital metasurfaces and reconfigurable metasurfaces have attracted increasing attention from researchers in the field of wireless communications. In particular, in recent years, intelligent metasurface technologies with market application value have been developed.

[0003] Overview

[0004] This disclosure provides a modulation unit, including:

[0005] A base plate includes: a substrate, and a metal layer disposed on one side of the substrate, the metal layer having slits; and

[0006] A driving layer, disposed on one side of the base plate, includes an electrode plate and a driving structure, wherein there is a gap between the electrode plate and the base plate;

[0007] The modulation unit includes at least one resonant structure, which includes the slit, the electrode plate, and the driving structure.

[0008] Within the same resonant structure, the driving structure is connected to the electrode plate and is used to drive the electrode plate to move in response to a driving signal, thereby changing the size of the overlap area between the orthographic projection of the electrode plate on the base plate and the slit, and adjusting the resonant frequency of the resonant structure.

[0009] In some embodiments, within the same resonant structure, the direction of movement of the electrode plate is perpendicular to the direction of extension of the slit.

[0010] In some embodiments, the slit includes a strip slit, the slit extending in the same direction as the strip slit.

[0011] In some embodiments, the slit further includes at least one branch slit that communicates with and intersects the strip slit.

[0012] In some embodiments, the at least one branch slit is located on the same side of the strip slit and within the same resonant structure, and the orthographic projection of the drive structure and at least a portion of the electrode plates on the base plate is located on the side of the strip slit opposite to the branch slit.

[0013] In some embodiments, the at least one resonant structure includes a first resonant structure and a second resonant structure, wherein the slit extending in the first resonant structure extends in a first direction, and the slit extending in the second resonant structure extends in a second direction, wherein the first direction and the second direction are perpendicular to each other.

[0014] In some embodiments, the at least one resonant structure further includes a third resonant structure and a fourth resonant structure, wherein the operating frequency band of the first resonant structure and the second resonant structure is a first frequency band, and the operating frequency band of the third resonant structure and the fourth resonant structure is a second frequency band, and the first frequency band is different from the second frequency band.

[0015] In some embodiments, the slit within the third resonant structure extends in the second direction, and the slit within the fourth resonant structure extends in the first direction; and

[0016] In the first direction, the orthographic projection of the first resonant structure on the base plate at least partially overlaps with the orthographic projection of the fourth resonant structure on the base plate;

[0017] In the second direction, the orthographic projection of the second resonant structure on the base plate at least partially overlaps with the orthographic projection of the third resonant structure on the base plate.

[0018] In some embodiments, the distance between the electrode plate and the base plate is less than or equal to the width of the slit, the width of the slit being the dimension of the slit perpendicular to its extension direction.

[0019] In some embodiments, the length of the slit along its extension direction is less than or equal to λ1 / 2n1, where λ1 is the operating wavelength of the resonant structure to which the slit belongs, and n1 is the equivalent refractive index of the material filling the slit and surrounding the slit.

[0020] In some embodiments, within the same resonant structure, the orthographic projection of the electrode on the base plate is centered within the slit along the extension direction of the slit.

[0021] In some embodiments, within the same resonant structure, along the extension direction of the slit, the ratio between the length of the electrode plate and the length of the slit is greater than or equal to 1 / 3 and less than or equal to 4 / 3.

[0022] In some embodiments, the driving structure includes a MEMS switch, the MEMS switch comprising: a stator comb electrode and a mover comb electrode disposed opposite to each other along the moving direction of the electrode plate;

[0023] The ridge of the stator comb electrode is fixed on the base plate, the teeth of the stator comb electrode face the moving comb electrode, the teeth of the moving comb electrode face the stator comb electrode, the two ends of the ridge of the moving comb electrode are fixed on the base plate, and the side surface of the ridge of the moving comb electrode away from the teeth is connected to the electrode plate through a cantilever beam.

[0024] The stator comb electrode and the mover comb electrode are used to generate electrostatic force under the action of the driving signal, and the mover comb electrode drives the electrode plate to move under the action of the electrostatic force.

[0025] In some embodiments, the ridges of the moving comb electrode are reused as the electrode plate.

[0026] In some embodiments, the electrode plate, the mover comb electrode, the stator comb electrode, and the cantilever beam are arranged in the same layer and are made of the same material.

[0027] In some embodiments, the driving layer includes at least one of the following: a conductive layer, and a highly doped crystalline silicon layer disposed on the side of the conductive layer near the base plate.

[0028] This disclosure provides a modulation device including a modulation panel, the modulation panel including at least one modulation unit as described in any embodiment.

[0029] In some embodiments, the modulation device includes a plurality of modulation panels stacked and spaced apart from each other.

[0030] In some embodiments, the spacing between two adjacent modulation panels is greater than or equal to λ2 / 2n2, where λ2 is the operating wavelength of the modulation device and n2 is the refractive index of the material filling the space between the two adjacent modulation panels.

[0031] This disclosure provides a driving method applied to a modulation device as described in any embodiment, the driving method comprising:

[0032] A driving signal is provided to the driving structure so that the driving structure responds to the driving signal and drives the electrode plate to move, thereby changing the size of the overlap area between the orthographic projection of the electrode plate on the base plate and the slit, and adjusting the resonant frequency of the resonant structure.

[0033] In some embodiments, when the at least one resonant structure includes a first resonant structure and a second resonant structure, and the extension direction of the slit located in the first resonant structure is perpendicular to the extension direction of the slit located in the second resonant structure, the step of providing a driving signal to the driving structure includes:

[0034] A first driving signal is provided to a first driving structure, and a second driving signal is provided to a second driving structure, so that the phase change of the electromagnetic wave generated by the first resonant structure is different from the phase change of the electromagnetic wave generated by the second resonant structure, thereby changing the polarization state of the electromagnetic wave; wherein, the first driving structure is a driving structure located within the first resonant structure, and the second driving structure is a driving structure located within the second resonant structure.

[0035] In some embodiments, when the modulation device includes a first modulation panel and a second modulation panel stacked and separated from each other, the step of providing a first driving signal to the first driving structure and a second driving signal to the second driving structure includes:

[0036] A first driving signal is provided to a first driving structure located in the first modulation panel and the second modulation panel respectively, and a second driving signal is provided to a second driving structure located in the first modulation panel and the second modulation panel respectively, so that the electromagnetic wave passing through the first modulation panel is converted from a first polarization state to a second polarization state, and the electromagnetic wave passing through the second modulation panel is converted from a second polarization state to a third polarization state.

[0037] In some embodiments, the first polarization state and the third polarization state are linear polarizations with different electric vector vibration directions, and the second polarization state is elliptical polarization or circular polarization; or

[0038] The first polarization state and the third polarization state are elliptical polarization or circular polarization with different directions of electric vector rotation, and the second polarization state is linear polarization.

[0039] This disclosure provides a method for fabricating a modulation unit, comprising:

[0040] A base plate is provided, the base plate comprising: a substrate, and a metal layer disposed on one side of the substrate, the metal layer having slits;

[0041] A driving layer is formed on one side of the base plate to obtain the modulation unit; wherein the driving layer includes an electrode plate and a driving structure, and there is a gap between the electrode plate and the base plate; the modulation unit includes at least one resonant structure, the resonant structure including the slit, the electrode plate and the driving structure, and within the same resonant structure, the driving structure is connected to the electrode plate for responding to a driving signal to drive the electrode plate to move, thereby changing the size of the overlap area between the orthographic projection of the electrode plate on the base plate and the slit, and adjusting the resonant frequency of the resonant structure.

[0042] In some embodiments, the driving structure includes a MEMS switch, and the MEMS switch includes: a stator comb electrode and a mover comb electrode disposed opposite to each other along the moving direction of the electrode plate, the comb teeth of the stator comb electrode facing the mover comb electrode, the comb teeth of the mover comb electrode facing the stator comb electrode, and the surface of the mover comb electrode facing away from the comb teeth being connected to the electrode plate via a cantilever beam. The step of providing the base plate includes:

[0043] Provide substrate;

[0044] A metal layer is formed on one side of the substrate, and the metal layer has slits;

[0045] A planarization layer and a passivation layer are sequentially formed on the side of the metal layer opposite to the substrate to obtain the base plate;

[0046] The step of forming a driving layer on one side of the base plate includes:

[0047] A sacrificial layer is formed on the side of the passivation layer opposite to the substrate;

[0048] Using a patterning process, the driving layer is formed on the side of the sacrificial layer opposite to the substrate. The driving layer includes the electrode plate, the mover comb electrode, the stator comb electrode, and the cantilever beam.

[0049] The sacrificial layer is etched to form a support structure and the gap. The support structure includes a first support pattern and a second support pattern. The first support pattern is located between the ridge of the stator comb electrode and the base plate, and is used to fix the ridge of the stator comb electrode to the base plate. The second support pattern is located between the two ends of the ridge of the mover comb electrode and the base plate, and is used to fix the two ends of the ridge of the mover comb electrode to the base plate. The gap is located at least between the electrode plate and the base plate, between the cantilever beam and the base plate, between the middle area of ​​the ridge of the mover comb electrode and the base plate, and between the comb teeth of the mover comb electrode and the base plate.

[0050] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are described below. Brief description of the attached diagram

[0052] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the scale in the drawings is for illustration only and does not represent the actual scale.

[0053] Figure 1 A schematic cross-sectional view of a modulation unit is shown.

[0054] Figure 2 A schematic diagram of the planar structure of the first modulation unit is shown.

[0055] Figure 3 A schematic diagram of the planar structure of the modulation unit corresponding to the two slits is shown.

[0056] Figure 4 The simulation results of the first resonant structure are shown schematically;

[0057] Figure 5 The simulation results of the second resonant structure are shown schematically;

[0058] Figure 6 The process of converting a linearly polarized electromagnetic wave into a nearly circularly polarized electromagnetic wave is illustrated schematically.

[0059] Figure 7 A schematic diagram of the planar structure of the second modulation unit is shown.

[0060] Figure 8 A schematic diagram of the planar structure of the third modulation unit is shown.

[0061] Figure 9 The simulation results of the resonant structure in the third modulation unit are shown schematically;

[0062] Figure 10 A schematic diagram of a planar structure of a modulation panel is shown.

[0063] Figure 11 A schematic cross-sectional view of a modulation device is shown.

[0064] Figure 12 The diagram schematically illustrates two types of linearly polarized electromagnetic waves with different electric vector vibration directions.

[0065] Figure 13 A schematic diagram illustrating the fabrication process of a modulation unit is shown.

[0066] Detailed description

[0067] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0068] This disclosure provides a modulation unit, with reference to Figure 1 A schematic cross-sectional view of a modulation unit is shown. Figure 1 As shown, the modulation unit includes: a base plate 10, including: a substrate 11, and a metal layer 12 disposed on one side of the substrate 11, the metal layer 12 having a slit 13; and a driving layer 14 disposed on one side of the base plate 10, including an electrode plate 15 and a driving structure 16, the electrode plate 15 having a gap h1 between it and the base plate 10.

[0069] Reference Figure 2 A schematic diagram of a planar structure of a modulation unit is shown, such as... Figure 2 As shown, the modulation unit includes at least one resonant structure 21. The resonant structure 21 includes a slit 13, an electrode 15, and a driving structure 16. Within the same resonant structure 21, the driving structure 16 is connected to the electrode 15 and is used to drive the electrode 15 to move in response to a driving signal, thereby changing the size of the overlap area between the orthographic projection of the electrode 15 on the base plate 10 and the slit 13, and adjusting the resonant frequency of the resonant structure 21.

[0070] like Figure 1 As shown, the electrode plate 15 is suspended on the base plate 10, and there is a gap h1 between the two.

[0071] By setting the driving structure 16 to drive the electrode plate 15 to translate, the projection position of the electrode plate 15 in the slit 13 is changed, thereby changing the resonant frequency of the resonant structure 21 composed of the slit 13 and the electrode plate 15. Therefore, the modulation unit provided in this disclosure can achieve tuning of the frequency, phase and polarization of electromagnetic waves.

[0072] The inventors discovered that if only the driving structure 16 and the electrode 15 are set in the resonant structure 21, the capacitance effect generated by the driving structure 16 moving the electrode 15 is very small, making it difficult to achieve tuning of the frequency, phase and polarization of electromagnetic waves.

[0073] By providing a slit 13 in the resonant structure 21, this disclosure can improve the sensitivity of the resonant frequency of the resonant structure 21 to the movement of the electrode 15. Even if a smaller electrode 15 is used or the movement range of the electrode 15 is small, the modulation unit provided by this disclosure can sensitively tune the frequency, phase and polarization of the electromagnetic wave passing through the resonant structure 21.

[0074] For example, such as Figure 1 As shown, the base plate 10 also includes a planarization layer 17 and a passivation layer 18 located on the side of the metal layer 12 facing away from the substrate 11. The planarization layer 17 is disposed close to the metal layer 12, and the driving layer 14 is disposed on the side of the passivation layer 18 facing away from the substrate 11. A support structure 19 may be disposed between the base plate 10 and the driving layer 14. Specifically, the support structure 19 may be disposed between the driving structure 16 and the base plate 10 for fixing the driving structure 16 to the base plate 10.

[0075] In practice, a sacrificial layer 143 can first be formed on the base plate 10 (see reference). Figure 13 Then, a driving layer 14 (including an electrode 15 and a driving structure 16) is patterned on the side of the sacrificial layer 143 away from the base plate 10. Then, the sacrificial layer 143 is etched to form a gap h1 between the electrode 15 and the base plate 10, and a support structure 19 is formed between the driving structure 16 and the base plate 10.

[0076] The driving layer 14 may include a conductive layer 142, and may also include a highly doped crystalline silicon layer 141 disposed on the side of the conductive layer 142 near the base plate 10. The conductive layer 142 may be made of one or more conductive materials such as copper, silver, aluminum, neodymium, and molybdenum. By providing a highly doped crystalline silicon layer 141, the stability and reliability of the driving structure 16 can be improved.

[0077] In some embodiments, within the same resonant structure 21, the direction of movement of the electrode 15 is perpendicular to the direction of extension of the slit 13.

[0078] like Figure 2 As shown, in the first resonant structure 31, the extension direction of the slit 13 is the first direction f1, and the movement direction of the electrode 15 is the second direction f2; in the second resonant structure 32, the extension direction of the slit 13 is the second direction f2, and the movement direction of the electrode 15 is the first direction f1. The second direction f2 and the first direction f1 are perpendicular to each other.

[0079] By setting the moving direction of the electrode 15 to be perpendicular to the extending direction of the slit 13, that is, the electrode 15 moves along the narrow side of the slit 13, the sensitivity of the resonant frequency of the resonant structure 21 to the movement of the electrode 15 can be further improved.

[0080] In some implementations, such as Figure 2 or Figure 3 As shown in Figure b, the slit 13 includes a strip slit 131, and the extension direction of the slit 13 is the same as the extension direction of the strip slit 131.

[0081] For example, such as Figure 3 As shown in Figure b, slit 13 is the strip slit 131.

[0082] In some implementations, such as Figure 2 As shown, the slit 13 may further include at least one branch slit 132, which communicates with and intersects with the strip slit 131.

[0083] For example, such as Figure 2 As shown, the branch slits 132 are perpendicular to the strip slits 131. Multiple branch slits 132 are located on the same side of the strip slits 131 and are parallel to each other. Figure 2 In the middle, slit 13 is a comb-shaped slit, strip slit 131 is a comb ridge, and branch slit 132 is a comb tooth.

[0084] By setting the branch slit 132, the length L2 of the strip slit 131 (i.e., the size of the strip slit 131 along its extension direction) can be shortened, thereby reducing the size of the electrode plate 15 and the modulation unit 20, which facilitates the miniaturization of the modulation unit and improves the practicality and reliability of the modulation unit. At the same time, the reduction in the size of the electrode plate 15 helps to reduce the driving voltage of the driving structure 16.

[0085] In some implementations, such as Figure 2 As shown, at least one branch slit 132 is located on the same side of the strip slit 131, and within the same resonant structure 21, the orthogonal projection of the drive structure 16 and at least a portion of the electrode plate 15 onto the base plate 10 is located on the side of the strip slit 131 opposite to the branch slit 132.

[0086] like Figure 2 As shown, in the first resonant structure 31, the extension direction of the strip slit 131 is the first direction f1, the branch slit 132 is located on the upper side of the strip slit 131, and the orthogonal projection of the driving structure 16 and at least part of the electrode plate 15 on the base plate 10 is located on the lower side of the strip slit 131; in the second resonant structure 32, the extension direction of the strip slit 131 is the second direction f2, the branch slit 132 is located on the right side of the strip slit 131, and the orthogonal projection of the driving structure 16 and at least part of the electrode plate 15 on the base plate 10 is located on the left side of the strip slit 131.

[0087] By setting the orthographic projections of the drive structure 16 and at least part of the electrode 15 onto the base plate 10, and the branch slit 132 on both sides of the strip slit 131, it is possible to avoid the drive structure 16 and the electrode 15 blocking the branch slit 132 and affecting the transmission rate of electromagnetic waves. On the other hand, it is possible to ensure that the overlapping area of ​​the orthographic projection of the electrode 15 onto the base plate 10 and the slit 13 is always within the strip slit 131, thereby further improving the sensitivity of the resonant frequency of the resonant structure 21 to the movement of the electrode 15.

[0088] like Figure 2 As shown, the length of the branch slit 132 (i.e. Figure 2 The dimension of the comb teeth of the central comb-shaped slit along the direction perpendicular to the extension of the strip slit 131 is W0, and the width of the branch slit 132 (i.e., Figure 2 The dimension of the comb teeth of the comb-shaped slit along the extension direction of the strip slit 131 is d, and the arrangement period of the branch slits 132 is P1.

[0089] like Figure 2 as well as Figure 3 As shown in Figure b, the width of the strip slit 131 (i.e., the dimension of the strip slit 131 along its extension direction perpendicular to its extension direction) is m+n, where m is the dimension of the strip slit 131 not covered by the electrode 15 along its extension direction perpendicular to its extension direction, and n is the dimension of the strip slit 131 covered by the electrode 15 along its extension direction perpendicular to its extension direction. The length of the electrode 15 (the dimension of the electrode 15 along the extension direction of the strip slit 131) is L1, and the width of the electrode 15 (the dimension of the electrode 15 along the extension direction perpendicular to the extension direction of the strip slit 131) is W1. In a resonant structure 21, the orthogonal projection position of the electrode 15 in the slit 13 has a significant impact on the resonant frequency of the resonant structure 21 or the frequency that the resonant structure 21 can transmit. Here, we use m:n to represent the projection position of the electrode 15 in the slit 13.

[0090] exist Figure 2 In this configuration, m+n = 60 micrometers, d = 60 micrometers, P1 = 210 micrometers, W0 = 500 micrometers, L1 = 1500 micrometers, W1 = 100 micrometers, and slit 13 comprises 14 periodic comb-tooth structures. Figure 3 In Figure b, m+n = 60 micrometers, and the length L2 of slit 13 is 4.4 millimeters.

[0091] Reference Figure 4 Figure a shows a resonant structure 21 employing a comb-shaped slit (as shown in the figure). Figure 2 The transmittance-frequency curve is shown in the figure. When m:n = 30:30, the transmittance of normally incident millimeter waves is as follows. Figure 4 As shown in the S1 curve. When the electrode 15 moves 20 micrometers under the drive of the driving structure 16, such that m:n = 10:50, the transmittance of the normally incident millimeter wave is as follows. Figure 4As shown in the S2 curve, it can be seen that by setting the driving structure 16 to drive the electrode plate 15 to translate, the frequency of the electromagnetic wave can be tuned. Figure 2 The resonant structure 21 shown can achieve high transmittance in the millimeter-wave band, and the insertion loss of the modulation unit is less than 2dB.

[0092] As the transmission frequency (the frequency of the electromagnetic wave transmitted through the resonant structure 21) changes, the transmission phase (the phase of the electromagnetic wave transmitted through the resonant structure 21) also changes accordingly. (Refer to...) Figure 4 Figure b in the diagram shows the phase-frequency curves of the resonant structure 21 employing a comb-shaped slit. When m:n = 30:30, the transmission phase of the normally incident millimeter wave is as follows: Figure 4 As shown in the S3 curve, when m:n = 10:50, the transmission phase of the normally incident millimeter wave is as follows: Figure 4 As shown in curve S4, it can be seen that when the projection position of electrode 15 on slit 13 changes by 20 micrometers, the transmission phase changes significantly. Therefore, Figure 2 The resonant structure 21 shown can perform phase tuning of electromagnetic waves.

[0093] Reference Figure 5 Figure a shows a resonant structure 21 employing a strip-shaped slit (as shown in the figure). Figure 3 The transmittance-frequency curve is shown in Figure b. When m:n = 30:30, the transmittance of normally incident millimeter waves is as follows. Figure 5 As shown in curve S5. When the electrode 15 moves 20 micrometers under the drive of the driving structure 16, such that m:n = 10:50, the transmittance of the normally incident millimeter wave is as follows. Figure 5 As shown in curve S6, it can be seen that by setting the driving structure 16 to drive the electrode plate 15 to translate, the frequency of the electromagnetic wave can be tuned. Figure 3 The resonant structure 21 shown in Figure b can achieve high transmittance in the millimeter-wave band, and the insertion loss of the modulation unit is less than 2dB.

[0094] Reference Figure 5 Figure b shows the phase-frequency curves of the resonant structure 21 using a strip-shaped slit. When m:n = 30:30, the transmission phase of the normally incident millimeter wave is as follows: Figure 5 As shown in curve S7, when m:n = 10:50, the transmission phase of a normally incident millimeter wave is as follows: Figure 5 As shown in the S8 curve, it can be seen that when the projection position of the electrode 15 on the slit 13 is displaced by 20 micrometers, the transmission phase changes significantly, thus achieving phase tuning of the electromagnetic wave.

[0095] contrast Figure 4 and Figure 5The simulation results of the two resonant structures 21 shown can be seen that the resonant structures using strip slits 131 and comb slits can both adjust the transmission frequency and transmission phase of electromagnetic waves.

[0096] Reference Figure 3 Two modulation units 20, employing comb-shaped slits and strip-shaped slits respectively, are shown. To ensure that the transmission frequency of both modulation units 20 is approximately 26 GHz, the length of the strip-shaped slit 131 (e.g., Figure 3 In Figure b, L2) is approximately the length of the comb-shaped slit (e.g., Figure 3 The area of ​​the modulation unit 20 using the strip slit 131 is approximately three times that of the modulation unit 20 using the comb slit, and the length of the electrode 15 corresponding to the strip slit 131 (e.g., L2 in Figure a) is three times that of L2 in Figure a. Figure 3 In Figure b, L1) is approximately the length of the electrode 15 corresponding to the comb-shaped slit (e.g., Figure 3 It is twice the size of L1 in Figure a.

[0097] The difference between the phase when m:n = 30:30 and the phase when m:n = 10:50 is defined as the phase change. (Refer to...) Figure 4 Figure c in the figure shows the phase change-frequency curve of the resonant structure 21 with comb-shaped slits caused by the movement of the electrode 15. (Refer to...) Figure 5 Figure c in the diagram shows the phase change-frequency curve of the resonant structure 21 with a strip slit caused by the movement of the electrode 15. Figure 4 Figure c in the middle and Figure 5 As can be seen from Figure c, at a frequency of 24.6 GHz, the phase change caused by the 20-micrometer movement of plate 15 is approximately 71°.

[0098] The phase change caused by the movement of electrode 15 can be used to achieve polarization conversion or polarization tuning of electromagnetic waves by the modulation unit. To achieve polarization tuning, in some embodiments, such as... Figure 2 As shown, at least one resonant structure 21 includes a first resonant structure 31 and a second resonant structure 32. The slit 13 located in the first resonant structure 31 extends in a first direction f1, and the slit 13 located in the second resonant structure 32 extends in a second direction f2. The first direction f1 and the second direction f2 are perpendicular to each other.

[0099] like Figure 2 As shown, the first driving structure 33 is the driving structure 16 located within the first resonant structure 31, and the second driving structure 34 is the driving structure 16 located within the second resonant structure 32.

[0100] In specific implementation, a first driving signal can be provided to the first driving structure 33 and a second driving signal can be provided to the second driving structure 34 so that the phase change generated by the electromagnetic wave passing through the first resonant structure 31 is different from the phase change generated by the electromagnetic wave passing through the second resonant structure 32, thereby changing the polarization state of the electromagnetic wave.

[0101] For example, such as Figure 2 As shown, the first resonant structure 31 and the second resonant structure 32 are located within the same modulation unit 20, respectively close to two mutually perpendicular sides of the modulation unit 20. Figure 2 The modulation unit 20 shown can provide a first driving signal to the driving structure 16 (i.e., the first driving structure 33) located within the first resonant structure 31, causing the electrode 15 located within the first resonant structure 31 to shift by, for example, 20 micrometers, from m:n = 30:30 to m:n = 10:50, thereby causing a phase change in the electromagnetic waves transmitted through the first resonant structure 31. A second driving signal is provided to the driving structure 16 (i.e., the second driving structure 34) located within the second resonant structure 32, causing the electrode plate 15 located within the second resonant structure 32 to shift by 0 micrometers, maintaining m:n = 30:30, thereby causing a phase change in the electromagnetic wave transmitted through the second resonant structure 32. That is, the phase difference between the electromagnetic wave passing through the first resonant structure 31 and the electromagnetic wave passing through the second resonant structure 32 is . Among them, phase change and It can be greater than 0° and less than π.

[0102] The phase difference can be controlled by adjusting the magnitudes of the first and second drive signals. The magnitude of the polarization state of electromagnetic waves can be adjusted to achieve the conversion of electromagnetic wave polarization state. For example, linearly polarized electromagnetic waves can be converted into elliptically polarized electromagnetic waves or circularly polarized electromagnetic waves, or elliptically polarized electromagnetic waves or circularly polarized electromagnetic waves can be converted into linearly polarized electromagnetic waves.

[0103] Reference Figure 6 The process of converting a 24.6 GHz linearly polarized millimeter wave into a near-circularly polarized millimeter wave is shown. Figure 6 In the diagram, t represents time, T represents the millimeter wave oscillation period, and the arrow represents the transmitted electric field vector. Figure 6 The observation plane shown is a plane 12 mm away from the emission surface of the modulation unit.

[0104] It should be noted that the extension direction of the slit 13 located in the first resonant structure 31 (i.e., the first direction f1) and the extension direction of the slit 13 located in the second resonant structure 32 (i.e., the second direction f2) may also intersect each other, and this disclosure does not limit this.

[0105] In some implementations, such as Figure 7 or Figure 8 As shown, at least one resonant structure 21 also includes a third resonant structure 81 and a fourth resonant structure 82. The operating frequency band of the first resonant structure 31 and the second resonant structure 32 is the first frequency band, and the operating frequency band of the third resonant structure 81 and the fourth resonant structure 82 is the second frequency band. The first frequency band and the second frequency band are different.

[0106] By setting two sets of resonant structures 21, one set of resonant structures 21 includes a first resonant structure 31 and a second resonant structure 32, and the other set of resonant structures 21 includes a third resonant structure 81 and a fourth resonant structure 82, since the two sets of resonant structures 21 operate at different frequency bands, the modulation unit can realize dual-band polarization conversion or expand the frequency range of polarization conversion.

[0107] The first and second frequency bands may not overlap or may partially overlap. When the first and second frequency bands partially overlap, continuous polarization tuning can be achieved.

[0108] In order for the third resonant structure 81 and the fourth resonant structure 82 to polarize and tune the transmitted electromagnetic waves, the extension direction of the slit 13 located in the third resonant structure 81 and the extension direction of the slit 13 located in the fourth resonant structure 82 can be perpendicular to each other (e.g., Figure 7 or Figure 8 (As shown) or intersecting with each other.

[0109] In practical implementation, for ease of design, the slits 13 of the first set of resonant structures (including the first resonant structure 31 and the second resonant structure 32) can be made to have the same shape and size, and the electrode plates 15 can be made to have the same shape and size. Similarly, the slits 13 of the second set of resonant structures (including the third resonant structure 81 and the fourth resonant structure 82) can be made to have the same shape and size, and the electrode plates 15 can be made to have the same shape and size.

[0110] In order to make the first frequency band different from the second frequency band, the parameters of the first set of resonant structures and the second set of resonant structures can be different. The parameters can include at least one of the following: the size of the slit 13, the shape of the slit 13, the size of the electrode 15, and the shape of the electrode 15, etc., which can affect the resonant frequency of the resonant structure 21.

[0111] In specific implementation, the first resonant structure 31, the second resonant structure 32, the third resonant structure 81, and the fourth resonant structure 82 can be located within the same modulation unit 20 (e.g., Figure 7 or Figure 8 (As shown), they can also be located in different modulation units 20, and this disclosure does not limit them.

[0112] like Figure 7 or Figure 8As shown, the first resonant structure 31 and the fourth resonant structure 82 are respectively arranged close to two opposite sides of the modulation unit 20, and the second resonant structure 32 and the third resonant structure 81 are respectively arranged close to the other two opposite sides of the modulation unit 20. Specifically, as... Figure 7 or Figure 8 As shown, the first resonant structure 31 is positioned near the upper side of the modulation unit 20, the fourth resonant structure 82 is positioned near the lower side of the modulation unit 20, the second resonant structure 32 is positioned near the right side of the modulation unit 20, and the third resonant structure 81 is positioned near the left side of the modulation unit 20.

[0113] In some embodiments, the slit 13 located in the third resonant structure 81 extends in the second direction f2, and the slit 13 located in the fourth resonant structure 82 extends in the first direction f1.

[0114] like Figure 7 or Figure 8 As shown, the extension direction of the slit 13 located in the fourth resonant structure 82 is the same as the extension direction of the slit 13 located in the first resonant structure 31, both being the first direction f1; the extension direction of the slit 13 located in the second resonant structure 32 is the same as the extension direction of the slit 13 located in the third resonant structure 81, both being the second direction f2. This allows for full utilization of the space of the modulation unit 20, enabling a compact arrangement of four resonant structures 21 within a limited space, which is beneficial for miniaturizing the modulation unit.

[0115] In some embodiments, in the first direction f1, the orthographic projection of the first resonant structure 31 on the base plate 10 and the orthographic projection of the fourth resonant structure 82 on the base plate 10 at least partially overlap, thereby making full use of the space of the modulation unit 20 in the first direction f1, which is beneficial to miniaturization of the modulation unit.

[0116] For example, such as Figure 7 or Figure 8 As shown, in the first direction f1, the orthogonal projection of the first resonant structure 31 on the base plate 10 completely covers the orthogonal projection of the fourth resonant structure 82 on the base plate 10.

[0117] In some embodiments, in the second direction f2, the orthographic projection of the second resonant structure 32 on the base plate 10 at least partially overlaps with the orthographic projection of the third resonant structure 81 on the base plate 10, thereby making full use of the space of the modulation unit 20 in the second direction f2, which is beneficial to the miniaturization of the modulation unit.

[0118] For example, such as Figure 7 or Figure 8 As shown, in the second direction f2, the orthogonal projection of the second resonant structure 32 on the base plate 10 completely covers the orthogonal projection of the third resonant structure 81 on the base plate 10.

[0119] In some implementations, refer to Figure 1 and Figure 2 The distance h1 between the electrode plate 15 and the base plate 10 is less than or equal to the width of the slit 13, where the width of the slit 13 is the dimension of the slit 13 perpendicular to its extension direction. Further, the distance h1 between the electrode plate 15 and the base plate 10 is less than or equal to the width W2 of the strip slit 131.

[0120] For example, the distance h1 between the electrode 15 and the base plate 10, that is, the suspension height h1 of the electrode 15 on the base plate 10, can be greater than or equal to 0.5 micrometers and less than or equal to 5 micrometers. In order to reduce the etching thickness and reduce the process complexity, the distance h1 between the electrode 15 and the base plate 10 can be greater than or equal to 1 micrometer and less than or equal to 2 micrometers.

[0121] In some implementations, such as Figure 2 or Figure 3 As shown, along the extension direction of slit 13, the length L2 of slit 13 is less than or equal to λ1 / 2n1, where λ1 is the operating wavelength of the resonant structure 21 to which slit 13 belongs, and n1 is the equivalent refractive index of the material filling slit 13 and the material surrounding slit 13.

[0122] In specific implementation, the length L2 of the slit 13 can be, for example, tens of nanometers, tens of micrometers or hundreds of micrometers, which can be determined according to the operating band of the resonant structure 21 to which the slit 13 belongs.

[0123] In practical implementation, within the same resonant structure 21, along the extension direction of the slit 13, the orthogonal projection of the electrode 15 onto the base plate 10 can be located at any position within the slit 13. To improve tuning sensitivity, in some embodiments, such as... Figure 2 or Figure 3 As shown, within the same resonant structure 21, along the extension direction of the slit 13, the orthogonal projection of the electrode 15 on the base plate 10 is centered on the slit 13.

[0124] The inventors discovered that the size of the electrode plate 15 connected to the drive structure 16 cannot be too large. If the size of the electrode plate 15 is too large, its weight will increase. On the one hand, this will require the drive structure 16 to use a larger drive voltage to drive the electrode plate 15; on the other hand, since the electrode plate 15 is suspended below, excessive weight will cause it to collapse and deform. In some embodiments, such as... Figure 2 or Figure 3 As shown, within the same resonant structure 21, along the extension direction of the slit 13, the ratio of the length L1 of the electrode 15 to the length L2 of the slit 13 is greater than or equal to 1 / 3 and less than or equal to 4 / 3.

[0125] To further reduce the weight of the electrode plate 15, the above ratio can be greater than or equal to 1 / 3 and less than or equal to 1 or 1 / 2.

[0126] In some implementations, such as Figure 2 As shown, in the direction perpendicular to the extension of the slit 13, the width W1 of the electrode 15 can be greater than or equal to the width W2 of the strip slit 131. In this way, on the one hand, the tuning range of frequency and phase can be improved, and on the other hand, the sensitivity of the resonant frequency of the resonant structure 21 to the movement of the electrode 15 can be improved.

[0127] In some embodiments, the thickness of the electrode 15 (i.e., the dimension of the electrode 15 along the normal direction of the substrate 11) may be greater than or equal to 0.5 micrometers and less than or equal to 50 micrometers. Further, the thickness of the electrode 15 may be greater than or equal to 3 micrometers and less than or equal to 5 micrometers. In specific implementations, the thickness of the electrode 15 can be determined based on the supporting force of the drive structure 16 and the level of manufacturing process; this disclosure does not impose specific limitations on this.

[0128] To further reduce the size of the modulation unit, in some embodiments, within the same resonant structure 21, if the length L2 of the slit 13 along its extension direction is greater than or equal to the length L3 of the drive structure 16, then the electrode 15 is positioned close to the edge of the modulation unit 20, and the drive structure 16 is located on the side of the electrode 15 away from the edge of the modulation unit 20. Figure 2 As shown; if the length L2 of the slit 13 is less than or equal to the length L3 of the drive structure 16 along the extension direction of the slit 13, then the drive structure 16 is disposed close to the edge of the modulation unit 20, and the electrode 15 is located on the side of the drive structure 16 away from the edge of the modulation unit 20.

[0129] In some implementations, such as Figure 2 As shown, the driving structure 16 includes a MEMS switch. The MEMS switch is a Micro-Electro-Mechanical System (MEMS) switch. In this disclosure, the MEMS switch can be an electrostatically driven cantilever beam switch used to turn low-frequency electrical signals on / off, or it can be a micro-switch that utilizes the relative translational motion between stator comb electrodes and mover comb electrodes to achieve the switching action.

[0130] MEMS switches are used in frequencies ranging from low frequencies to microwaves, millimeter waves, and optical bands. Potential applications of MEMS switches in RF systems include: antenna transceiver and signal filtering path selection and interconnection in multi-band communication systems, electrically controlled phase shifters, smart antennas, and reconfigurable metasurfaces. The requirements for MEMS switches in electrically controlled reconfigurable antennas are: low switching loss, low insertion loss when in the ON state, high isolation when in the OFF state, low drive voltage, and fast switching speed, among others.

[0131] In some implementations, such as Figure 2 As shown, the MEMS switch includes a stator comb electrode 35 and a mover comb electrode 36 disposed opposite to each other along the moving direction of the electrode plate 15. The ridges of the stator comb electrode 35 are fixed to the base plate 10, the teeth of the stator comb electrode 35 face the mover comb electrode 36, and the teeth of the mover comb electrode 36 face the stator comb electrode 35. Both ends of the ridge of the mover comb electrode 36 are fixed to the base plate 10, and the surface of the ridge of the mover comb electrode 36 facing away from the teeth is connected to the electrode plate 15 via a cantilever beam 37.

[0132] The stator comb electrode 35 and the mover comb electrode 36 are used to generate electrostatic force under the action of the drive signal. Under the action of the electrostatic force, the mover comb electrode 36 drives the electrode plate 15 to move.

[0133] like Figure 2 As shown, the support structure 19 includes a first support pattern 23 and a second support pattern 24. The first support pattern 23 is located between the comb ridge of the stator comb electrode 35 and the base plate 10, and is used to fix the comb ridge of the stator comb electrode 35 to the base plate 10. The second support pattern 24 is located between the two ends of the comb ridge of the mover comb electrode 36 and the base plate 10, and is used to fix the two ends of the comb ridge of the mover comb electrode 36 (i.e., the fixed ends SS) to the base plate 10. The gap h1 is located between the electrode plate 15 and the base plate 10, between the cantilever beam 37 and the base plate 10, between the middle area of ​​the comb ridge of the mover comb electrode 36 and the base plate 10, and between the comb teeth of the mover comb electrode 36 and the base plate 10. It can also be located between the comb teeth of the stator comb electrode 35 and the base plate 10. The middle area of ​​the comb ridge of the mover comb electrode 36 refers to the comb ridge portion located between the two fixed ends SS.

[0134] like Figure 2 As shown, the comb teeth of the stator comb electrode 35 and the comb teeth of the mover comb electrode 36 are parallel to each other and interlaced. The mover comb electrode 36 is connected to the drive line 22. Under the action of the drive signal input to the drive line 22, the mover comb electrode 36 can move closer to or away from the stator comb electrode 35, thereby driving the electrode plate 15 to translate.

[0135] In related technologies, the distance by which a single mover comb electrode 36 drives the electrode plate 15 to translate is approximately 10 micrometers to 25 micrometers.

[0136] Reference Figure 2 The length L3 of the comb ridges of the stator comb electrode 35 and the comb length W3 of the mover comb electrode 36 can be on the order of millimeters, and the length of the comb teeth can be on the order of tens of micrometers to 100 micrometers.

[0137] For example, the comb tooth length W3 of the stator comb electrode 35 and the mover comb electrode 36 is about 50 micrometers, the comb tooth width is about 10 micrometers, and the comb ridge length L3 is about 1.0 millimeter.

[0138] The cantilever beam 37 has a gap with the base plate 10, which provides a certain degree of rigidity and serves to support the pole plate 15.

[0139] In some implementations, such as Figure 8 As shown, the ridges of the moving comb electrode 36 are reused as electrode plates 15. In this implementation, the frequency, phase, and polarization tuning of the electromagnetic wave are directly achieved by utilizing the movement of the moving comb electrode 36 on the slit 13.

[0140] exist Figure 8 In this configuration, the teeth of the stator comb electrode 35 face the moving part comb electrode 36, and the teeth of the moving part comb electrode 36 face the stator comb electrode 35. Since the ridges of the moving part comb electrode 36 are reused as electrode plates 15, there is no need to additionally set up a substrate 15 and a cantilever beam 37, which is beneficial for the miniaturization of the modulation unit. Figure 8 In this process, the method by which the stator comb electrode 35 and the mover comb electrode 36 are fixed on the base plate 10 can be the same as... Figure 2 Same, please refer to the details. Figure 2 The description will not be repeated here.

[0141] For example, such as Figure 8 As shown, the slit 13 is strip-shaped (as shown in the image). Figure 8 As shown in 131), the orthographic projection of the comb teeth of the stator comb electrode 35 onto the base plate 10 is close to one side of the strip slit 131. Figure 8 In the stator comb electrode 35, the ridge length L3 is 600 micrometers, the tooth length W3 is 50 micrometers, the tooth width is 12 micrometers, and the tooth period is 30 micrometers. The width W2 of the strip slit 131 is 30 micrometers, and the length L2 of the strip slit 131 is 4.4 millimeters. The tooth suspension height h1 of the mover comb electrode 36 is 3 micrometers.

[0142] In practical implementation, the moving comb electrode 36 moves above the slit 13 under the drive signal, which can form an open state (e.g., Figure 8 Figure a shows any resonant structure 21) and off-state (such as) within the modulation unit. Figure 8 Figure b shows the second resonant structure 32 and the third resonant structure 81 within the modulation unit.

[0143] In the open state, such as Figure 8In any resonant structure 21 within the modulation unit shown in Figure a, the orthogonal projection of the comb ridge (i.e., electrode plate 15) of the mover comb electrode 36 onto the base plate 10 may not cover the strip slit 131. The comb teeth of the mover comb electrode 36 and the comb teeth of the stator comb electrode 35 may partially overlap, as shown in... Figure 8 The overlap in Figure a is 10 micrometers.

[0144] In the off state, such as Figure 8 Figure b shows the second resonant structure 32 and the third resonant structure 81 in the modulation unit. The comb teeth of the mover comb electrode 36 move closer to the stator comb electrode 35 by about 20 micrometers, and the length of the comb teeth overlap reaches 30 micrometers. After the movement, the orthogonal projection of the comb ridge (i.e. the electrode plate 15) of the mover comb electrode 36 on the base plate 10 at least partially covers the slit 13.

[0145] It should be noted that, in the open state, the distance between the ridges of the moving comb electrode 36 and the slit 13 needs to be less than the moving distance of the moving comb electrode 36, to ensure that the moving comb electrode 36 at least partially covers the slit 13 after moving. Figure 8 In Figure a, in the open state, the distance between the comb ridge of the mover comb electrode 36 and the slit 13 is approximately 10 micrometers.

[0146] Reference Figure 9 Figure a shows the... Figure 8 The transmittance-frequency curves of the resonant structure 21 in the on and off states are shown. The transmittance-frequency curve in the on state is s9, and the transmittance-frequency curve in the off state is s10. It can be seen that by reusing the comb ridges of the moving comb electrode 36 as the electrode plate 15, the frequency of the electromagnetic wave can be tuned. Since the comb teeth of the moving comb electrode 36 are directly above the slit 13, the transmittance of the electromagnetic wave is relatively low, but the peak transmittance can still reach 60%.

[0147] like Figure 8 As shown, when the modulation unit 20 includes a first resonant structure 31 and a second resonant structure 32, a phase difference of nearly 75° can be achieved at 26.5 GHz by utilizing the frequency offset between the on and off states (e.g., ...). Figure 9 As shown in Figure b), the phase difference can then be used to adjust the polarization of electromagnetic waves.

[0148] In some embodiments, the electrode plate 15, the mover comb electrode 36, the stator comb electrode 35, and the cantilever beam 37 are arranged in the same layer and are made of the same material. In this way, the electrode plate 15, the mover comb electrode 36, the stator comb electrode 35, and the cantilever beam 37 can be formed simultaneously using the same process, thereby simplifying the process flow.

[0149] For example, the electrode plate 15, the mover comb electrode 36, the stator comb electrode 35, and the cantilever beam 37 may comprise the same metallic material, such as molybdenum / neodymium / molybdenum material.

[0150] The drive signal provided to the drive structure 16 may include a reference voltage provided to the stator comb electrode 35 and a drive voltage provided to the mover comb electrode 36. The reference voltage can be a fixed voltage (e.g., ground potential), in which case the drive lines 22 connecting the multiple stator comb electrodes 35 can be interconnected (e.g., ...). Figure 8 (As shown), this disclosure does not limit it.

[0151] In order to enable independent control of each drive structure 16, the drive lines 22 connecting the multiple mover comb electrodes 36 can be independent of each other (e.g., Figure 7 and Figure 8 (as shown), or interconnected as needed, this disclosure does not limit this.

[0152] This disclosure provides a modulation device, including a modulation panel 90, such as... Figure 10 As shown, the modulation panel 90 includes at least one modulation unit 20 as provided in any embodiment.

[0153] Those skilled in the art will understand that the modulation device has the advantages of the modulation unit 20.

[0154] The modulation panel may include one or more modulation units 20, and each modulation unit 20 may include one or more resonant structures 21. Figure 10 In the modulation panel 90, there are multiple modulation units 20 arranged in an array along the row and column directions, and each modulation unit 20 includes two resonant structures 21.

[0155] In some implementations, such as Figure 10 As shown, the arrangement period P0 of the modulation units 20 arranged in the array can be less than λ2 / 2, where λ2 is the operating wavelength of the modulation device. Multiple subwavelength scale modulation units 20 are arranged in an array to form a metasurface array.

[0156] In some implementations, such as Figure 11 As shown, the modulation device includes multiple modulation panels 90 stacked and spaced apart from each other. The distance between two adjacent modulation panels 90 is h2.

[0157] When the modulation unit 20 in the modulation panel 90 includes a first resonant structure 31 and a second resonant structure 32, the modulation panel 90 can perform polarization conversion on the incident electromagnetic wave, changing the polarization state of the electromagnetic wave. In this way, multiple modulation panels 90 stacked together can perform multiple polarization conversions on the incident electromagnetic wave.

[0158] like Figure 11 As shown, the modulation device includes a first modulation panel 91 and a second modulation panel 92 stacked and separated from each other, and the modulation unit 20 in the first modulation panel 91 and the modulation unit 20 in the second modulation panel 92 are as follows: Figure 2 As shown, it includes at least a first resonant structure 31 and a second resonant structure 32.

[0159] In specific implementation, refer to Figure 11 and Figure 2 The same or different first driving signals can be provided to the first driving structure 33 located in the first modulation panel 91 and the second modulation panel 92 respectively, and the same or different second driving signals can be provided to the second driving structure 34 located in the first modulation panel 91 and the second modulation panel 92 respectively, so that the electromagnetic wave passing through the first modulation panel 91 is converted from the first polarization state to the second polarization state, and the electromagnetic wave passing through the second modulation panel 92 is converted from the second polarization state to the third polarization state.

[0160] When the first modulation panel 91 and the second modulation panel 92 have the same structure, and provide the same first driving signal to the first driving structure 33 located in the first modulation panel 91 and the second modulation panel 92 respectively, and provide the same second driving signal to the second driving structure 34 located in the first modulation panel 91 and the second modulation panel 92 respectively, electromagnetic waves can generate a phase difference ψ1 after passing through the first resonant structure 31 and the second resonant structure 32 in the first modulation panel 91, and electromagnetic waves can also generate a phase difference ψ1 after passing through the first resonant structure 31 and the second resonant structure 32 in the second modulation panel 92. The phase change ψ1 can be greater than 0° and less than π.

[0161] In some embodiments, the first polarization state and the third polarization state can be linear polarization with different directions of electric vector vibration, and the second polarization state can be elliptical polarization or circular polarization. When the aforementioned phase difference ψ1 = π / 2, the first polarization state (e.g.) Figure 12 (as shown in Figure a) and the third polarization state (as shown in Figure a) Figure 12 Figure b shows linear polarization with the electric vector vibration directions perpendicular to each other, and the second polarization state is circular polarization.

[0162] In some embodiments, the first polarization state and the third polarization state are elliptical polarization or circular polarization with different directions of electric vector rotation (or different chirality), and the second polarization state is linear polarization. When the aforementioned phase difference ψ1 = π / 2, the first polarization state is left-handed circular polarization and the third polarization state is right-handed circular polarization, or the first polarization state is right-handed circular polarization and the third polarization state is left-handed circular polarization.

[0163] To reduce the insertion loss of the modulation device, in some implementations, such as Figure 11As shown, the distance h2 between two adjacent modulation panels 90 is greater than or equal to λ2 / 2n2, where λ2 is the operating wavelength of the modulation device and n2 is the refractive index of the material filling the space between the two adjacent modulation panels 90.

[0164] By setting the spacing between two adjacent modulation panels 90 to be greater than or equal to λ2 / 2n2, electromagnetic waves passing through the previous modulation panel 90 can be incident on the next modulation panel 90 in the form of plane waves. This can improve the transmittance of electromagnetic waves through the modulation device and reduce the insertion loss of the modulation device.

[0165] It should be noted that the spacing h2 between two adjacent modulation panels 90 can also be less than λ2 / 2n2, and this disclosure does not limit this.

[0166] The modulation device disclosed herein can be, for example, an antenna, or a product or component including an antenna, such as a mobile phone, tablet computer, television, laptop computer, digital photo frame, navigator, etc.

[0167] The antenna may also include a transmitting module for transmitting radio frequency (RF) signals. Specifically, the RF signals may first be frequency-, phase-, or polarization-modulated by a modulator before being transmitted to the transmitting module.

[0168] This disclosure provides a driving method applied to a modulation device as provided in any embodiment, with reference to... Figure 2 The driving method includes:

[0169] Step S01: Provide a driving signal to the driving structure 16 so that the driving structure 16 responds to the driving signal and drives the electrode plate 15 to move, thereby changing the size of the overlap area between the orthographic projection of the electrode plate 15 on the base plate 10 and the slit 13, and adjusting the resonant frequency of the resonant structure 21.

[0170] In some implementations, reference Figure 2 When at least one resonant structure 21 includes a first resonant structure 31 and a second resonant structure 32, and the extension direction of the slit 13 located in the first resonant structure 31 is perpendicular to the extension direction of the slit 13 located in the second resonant structure 32, the step of providing a driving signal to the driving structure 16 in step S01 includes:

[0171] Step S11: Provide a first driving signal to the first driving structure 33 and a second driving signal to the second driving structure 34, so that the phase change generated by the electromagnetic wave passing through the first resonant structure 31 is different from the phase change generated by the electromagnetic wave passing through the second resonant structure 32, so as to change the polarization state of the electromagnetic wave.

[0172] The first driving structure 33 is the driving structure 16 located within the first resonant structure 31, and the second driving structure 34 is the driving structure 16 located within the second resonant structure 32.

[0173] In some implementations, reference Figure 11 and Figure 2 When the modulation device includes a first modulation panel 91 and a second modulation panel 92 that are stacked and separated from each other, the step S11, which involves providing a first driving signal to the first driving structure 33 and a second driving signal to the second driving structure 34, includes:

[0174] Step S21: Provide the same or different first driving signals to the first driving structure 33 located in the first modulation panel 91 and the second modulation panel 92 respectively, and provide the same or different second driving signals to the second driving structure 34 located in the first modulation panel 91 and the second modulation panel 92 respectively, so that the electromagnetic wave passing through the first modulation panel 91 is converted from the first polarization state to the second polarization state, and the electromagnetic wave passing through the second modulation panel 92 is converted from the second polarization state to the third polarization state.

[0175] In some implementations, the first polarization state and the third polarization state are linear polarizations with different directions of electric vector vibration, and the second polarization state is elliptical polarization or circular polarization.

[0176] In some implementations, the first polarization state and the third polarization state are elliptical polarization or circular polarization with different directions of electric vector rotation, and the second polarization state is linear polarization.

[0177] It should be noted that the driving method may include more steps, depending on actual needs, and this disclosure does not impose any limitations on this. For a detailed description of the driving method and its technical effects, please refer to the description of the implementation of the modulation unit or modulation device above; it will not be repeated here.

[0178] This disclosure provides a method for fabricating a modulation unit, referring to... Figure 1 The preparation method includes:

[0179] Step S31: Provide a base plate 10, the base plate 10 including: a substrate 11, and a metal layer 12 disposed on one side of the substrate 11, the metal layer 12 having a slit 13.

[0180] Step S32: A driving layer 14 is formed on one side of the base plate 10 to obtain a modulation unit; wherein, the driving layer 14 includes an electrode plate 15 and a driving structure 16, and there is a gap h1 between the electrode plate 15 and the base plate 10. The modulation unit includes at least one resonant structure 21, which includes a slit 13, an electrode plate 15 and a driving structure 16. Within the same resonant structure 21, the driving structure 16 is connected to the electrode plate 15 and is used to drive the electrode plate 15 to move in response to a driving signal, so as to change the size of the overlap area between the orthographic projection of the electrode plate 15 on the base plate 10 and the slit 13, and adjust the resonant frequency of the resonant structure 21.

[0181] The modulation unit provided in any of the above embodiments can be prepared using the preparation method provided in this disclosure.

[0182] In some implementations, such as Figure 2 As shown, the driving structure 16 includes a MEMS switch, and the MEMS switch includes a stator comb electrode 35 and a mover comb electrode 36 disposed opposite to each other along the moving direction of the electrode plate 15. The comb teeth of the stator comb electrode 35 face the mover comb electrode 36, and the comb teeth of the mover comb electrode 36 face the stator comb electrode 35. The surface of the mover comb electrode 36 facing away from the comb teeth is connected to the electrode plate 15 via a cantilever beam 37. (Refer to...) Figure 1 Step S31 may specifically include:

[0183] Step S41: Provide substrate 11.

[0184] Step S42: A metal layer 12 is formed on one side of the substrate 11, and the metal layer 12 has a slit 13.

[0185] Step S43: A planarization layer 17 and a passivation layer 18 are sequentially formed on the side of the metal layer 12 away from the substrate 11 to obtain the base plate 10.

[0186] Step S32 may specifically include:

[0187] Step S44: A sacrificial layer 143 is formed on the side of the passivation layer 18 away from the substrate 11.

[0188] Step S45: Using a patterning process, a driving layer 14 is formed on the side of the sacrificial layer 143 facing away from the substrate 11. The driving layer 14 includes an electrode plate 15, a mover comb electrode 36, a stator comb electrode 35, and a cantilever beam 37.

[0189] Step S46: Etch the sacrificial layer 143 to form the support structure 19 and the gap h1. (Refer to...) Figure 2The support structure 19 includes a first support pattern 23 and a second support pattern 24. The first support pattern 23 is located between the comb ridge of the stator comb electrode 35 and the base plate 10, and is used to fix the comb ridge of the stator comb electrode 35 to the base plate 10. The second support pattern 24 is located between the two ends of the comb ridge of the mover comb electrode 36 (i.e., the fixed ends SS) and the base plate 10, and is used to fix the two ends of the comb ridge of the mover comb electrode 36 to the base plate 10. The gap h1 is located at least between the electrode plate 15 and the base plate 10, between the cantilever beam 37 and the base plate 10, between the middle area of ​​the comb ridge of the mover comb electrode 36 and the base plate 10, and between the comb teeth of the mover comb electrode 36 and the base plate 10.

[0190] For example, such as Figure 13 As shown, the fabrication method of the modulation unit may specifically include the following steps:

[0191] Step 1: A metal layer 12 is patterned on a substrate 11, the metal layer 12 having a slit 13.

[0192] Step 2: A planarization layer 17 and a passivation layer 18 are sequentially formed on the side of the metal layer 12 away from the substrate 11 to obtain the base plate 10.

[0193] Step 3: Form a sacrificial layer 143 on the side of the passivation layer 18 that is away from the substrate 11.

[0194] Step 4: Deposit silicon material 148 on the side of the sacrificial layer 143 away from the substrate 11.

[0195] Step 5: Crystallize and highly ion-dopat silicon material 148 to obtain highly doped crystallized silicon material 147.

[0196] Step 6: A conductive material 146 is formed on the side of the highly doped crystalline silicon material 147 facing away from the substrate 11 to obtain a driving material layer 144.

[0197] Step 7: Using an exposure and development process, a photoresist pattern 145 is formed on the side of the driving material layer 144 facing away from the substrate 11.

[0198] Step 8: Etch the exposed driving material layer 144 to remove the photoresist pattern 145, forming the driving layer 14. The driving layer 14 includes a highly doped silicon layer 141 and a conductive layer 142, with the highly doped silicon layer 141 located on the side of the conductive layer 142 closest to the base plate 10. By setting the highly doped silicon layer 141, the stability and reliability of the resonant structure 21 can be improved.

[0199] Step 9: Etch the sacrificial layer 143 below the driving layer 14 to form a support structure 19 (including a first support pattern 23 and a second support pattern 24) and a gap h1, thus obtaining the modulation unit.

[0200] It should be noted that the highly doped silicon material 147 is not necessary. In steps 4 to 6, a conductive material 146 can be directly formed on the side of the sacrificial layer 143 facing away from the substrate 11 to obtain the driving material layer 144. The driving layer 14 prepared in this way includes the conductive layer 142 but does not include the highly doped silicon layer 141, thereby simplifying the process flow.

[0201] In this disclosure, "multiple" means two or more, and "at least one" means one or more, unless otherwise expressly and specifically defined.

[0202] In this disclosure, the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this disclosure.

[0203] In this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0204] The terms "an embodiment," "some embodiments," "exemplary embodiments," "one or more embodiments," "example," "one example," "some examples," etc., used herein are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be included in any suitable manner in any one or more embodiments or examples.

[0205] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0206] In describing some embodiments, the terms "coupled" and "connected" may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "coupled" or "communicatively coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0207] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0208] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0209] As used herein, depending on the context, the term “if” may optionally be interpreted as meaning “when”, “in the event of”, “in response to determination”, or “in response to detection”. Similarly, depending on the context, the phrase “if it is determined that…” or “if [the stated condition or event] is detected” may optionally be interpreted as meaning “in the event of determination that…”, “in response to determination that…”, “when [the stated condition or event] is detected”, or “in response to the detection of [the stated condition or event]”.

[0210] The use of “for” or “configured to” in this article implies an open and inclusive language that does not preclude the applicability to or configuration of devices to perform additional tasks or steps.

[0211] The use of "based on" or "according to" in this document implies openness and inclusiveness. A process, step, calculation, or other action based on one or more of the stated conditions or values ​​may, in practice, be based on other conditions or values ​​beyond those stated.

[0212] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0213] As used herein, “parallel,” “perpendicular,” “equal,” and “flush” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where the acceptable range of deviation for approximate parallelism can be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where the acceptable range of deviation for approximate perpendicularity can also be, for example, within 5°. “Equal” includes absolute equality and approximate equality, where the acceptable range of deviation for approximate equality can be, for example, the difference between the two equals being less than or equal to 5% of either one. “Flush” includes absolute flush and approximate flush, where the acceptable range of deviation for approximate flush can be, for example, the distance between the flush twos being less than or equal to 5% of either one of the dimensions.

[0214] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0215] This document describes exemplary embodiments with reference to cross-sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, etched regions shown as rectangular would typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A modulation unit, comprising: A base plate includes: a substrate, and a metal layer disposed on one side of the substrate, the metal layer having slits; and A driving layer, disposed on one side of the base plate, includes an electrode plate and a driving structure, wherein there is a gap between the electrode plate and the base plate; The modulation unit includes at least one resonant structure, which includes the slit, the electrode plate, and the driving structure. Within the same resonant structure, the driving structure is connected to the electrode plate and is used to drive the electrode plate to move in response to a driving signal, thereby changing the size of the overlap area between the orthographic projection of the electrode plate on the base plate and the slit, adjusting the resonant frequency of the resonant structure, and the moving direction of the electrode plate is perpendicular to the extension direction of the slit. The at least one resonant structure includes a first resonant structure and a second resonant structure. The slit extending in the first resonant structure is a first direction, and the slit extending in the second resonant structure is a second direction. The first direction and the second direction are perpendicular to each other.

2. The modulation unit according to claim 1, wherein, The slit includes a strip-shaped slit, and the slit extends in the same direction as the strip-shaped slit.

3. The modulation unit according to claim 2, wherein, The slit further includes at least one branch slit, which communicates with and intersects the strip slit.

4. The modulation unit according to claim 3, wherein, The at least one branch slit is located on the same side of the strip slit and within the same resonant structure, and the orthographic projection of the driving structure on the base plate and the orthographic projection of at least a portion of the electrode plates on the base plate are located on the side of the strip slit opposite to the branch slit.

5. The modulation unit according to claim 1, wherein, The at least one resonant structure further includes a third resonant structure and a fourth resonant structure. The operating frequency band of the first resonant structure and the second resonant structure is a first frequency band, and the operating frequency band of the third resonant structure and the fourth resonant structure is a second frequency band. The first frequency band is different from the second frequency band.

6. The modulation unit according to claim 5, wherein, The slit located in the third resonant structure extends in the second direction, and the slit located in the fourth resonant structure extends in the first direction; and In the first direction, the orthographic projection of the first resonant structure on the base plate at least partially overlaps with the orthographic projection of the fourth resonant structure on the base plate; In the second direction, the orthographic projection of the second resonant structure on the base plate at least partially overlaps with the orthographic projection of the third resonant structure on the base plate.

7. The modulation unit according to any one of claims 1 or 3-6, wherein, The distance between the electrode plate and the base plate is less than or equal to the width of the slit, where the width of the slit is the dimension of the slit perpendicular to its extension direction.

8. The modulation unit according to any one of claims 1 or 3-6, wherein, Along the extension direction of the slit, the length of the slit is less than or equal to λ1 / 2n1, where λ1 is the operating wavelength of the resonant structure to which the slit belongs, and n1 is the equivalent refractive index of the material filling the slit and the material surrounding the slit.

9. The modulation unit according to any one of claims 1 or 3-6, wherein, Within the same resonant structure, along the extension direction of the slit, the orthogonal projection of the electrode plate on the base plate is centered within the slit.

10. The modulation unit according to any one of claims 1 or 3-6, wherein, Within the same resonant structure, along the extension direction of the slit, the ratio between the length of the electrode plate and the length of the slit is greater than or equal to 1 / 3 and less than or equal to 4 / 3.

11. The modulation unit according to any one of claims 1 or 3-6, wherein, The driving structure includes a MEMS switch, which includes a stator comb electrode and a mover comb electrode disposed opposite to each other along the moving direction of the electrode plate. The ridge of the stator comb electrode is fixed on the base plate, the teeth of the stator comb electrode face the moving comb electrode, the teeth of the moving comb electrode face the stator comb electrode, the two ends of the ridge of the moving comb electrode are fixed on the base plate, and the side surface of the ridge of the moving comb electrode away from the teeth is connected to the electrode plate through a cantilever beam. The stator comb electrode and the mover comb electrode are used to generate electrostatic force under the action of the driving signal, and the mover comb electrode drives the electrode plate to move under the action of the electrostatic force.

12. The modulation unit according to claim 11, wherein, The comb ridges of the moving comb electrode are reused as the electrode plate.

13. The modulation unit according to claim 11, wherein, The electrode plate, the moving part comb electrode, the stator comb electrode, and the cantilever beam are arranged in the same layer and are made of the same material.

14. The modulation unit according to any one of claims 1 or 3-6, wherein, The driving layer includes: a conductive layer, and a highly doped crystalline silicon layer disposed on the side of the conductive layer near the base plate.

15. A modulation device comprising a modulation panel, the modulation panel including at least one modulation unit as claimed in any one of claims 1 to 14.

16. The modulation device according to claim 15, wherein, The modulation device includes a plurality of modulation panels that are stacked and spaced apart from each other.

17. The modulation device according to claim 16, wherein, The spacing between two adjacent modulation panels is greater than or equal to λ2 / 2n2, where λ2 is the operating wavelength of the modulation device and n2 is the refractive index of the material filling the space between the two adjacent modulation panels.

18. A driving method applied to a modulation device as described in any one of claims 15 to 17, the driving method comprising: A driving signal is provided to the driving structure so that the driving structure responds to the driving signal and drives the electrode plate to move, thereby changing the size of the overlap area between the orthographic projection of the electrode plate on the base plate and the slit, and adjusting the resonant frequency of the resonant structure.

19. The driving method according to claim 18, wherein, When the at least one resonant structure includes a first resonant structure and a second resonant structure, and the extension direction of the slit located in the first resonant structure is perpendicular to the extension direction of the slit located in the second resonant structure, the step of providing a driving signal to the driving structure includes: A first driving signal is provided to a first driving structure, and a second driving signal is provided to a second driving structure, so that the phase change of the electromagnetic wave generated by the first resonant structure is different from the phase change of the electromagnetic wave generated by the second resonant structure, thereby changing the polarization state of the electromagnetic wave; wherein, the first driving structure is a driving structure located within the first resonant structure, and the second driving structure is a driving structure located within the second resonant structure.

20. The driving method according to claim 19, wherein, When the modulation device includes a first modulation panel and a second modulation panel stacked and separated from each other, the steps of providing a first driving signal to the first driving structure and providing a second driving signal to the second driving structure include: A first driving signal is provided to a first driving structure located in the first modulation panel and the second modulation panel respectively, and a second driving signal is provided to a second driving structure located in the first modulation panel and the second modulation panel respectively, so that the electromagnetic wave passing through the first modulation panel is converted from a first polarization state to a second polarization state, and the electromagnetic wave passing through the second modulation panel is converted from a second polarization state to a third polarization state.

21. The driving method according to claim 20, wherein, The first polarization state and the third polarization state are linear polarizations with different electric vector vibration directions, and the second polarization state is elliptical polarization or circular polarization; or The first polarization state and the third polarization state are elliptical polarization or circular polarization with different directions of electric vector rotation, and the second polarization state is linear polarization.

22. A method for fabricating a modulation unit, comprising: A base plate is provided, the base plate comprising: a substrate, and a metal layer disposed on one side of the substrate, the metal layer having slits; A driving layer is formed on one side of the base plate to obtain the modulation unit; wherein, the driving layer includes an electrode plate and a driving structure, and there is a gap between the electrode plate and the base plate; the modulation unit includes at least one resonant structure, the resonant structure including: the slit, the electrode plate and the driving structure, within the same resonant structure, the driving structure is connected to the electrode plate and is used to drive the electrode plate to move in response to a driving signal, so as to change the size of the overlap area between the orthographic projection of the electrode plate on the base plate and the slit, and adjust the resonant frequency of the resonant structure; the moving direction of the electrode plate is perpendicular to the extension direction of the slit; the at least one resonant structure includes a first resonant structure and a second resonant structure, the extension direction of the slit located in the first resonant structure is the first direction, the extension direction of the slit located in the second resonant structure is the second direction, and the first direction and the second direction are perpendicular to each other.

23. The preparation method according to claim 22, wherein, The driving structure includes a MEMS switch, and the MEMS switch includes: a stator comb electrode and a mover comb electrode disposed opposite to each other along the moving direction of the electrode plate, the comb teeth of the stator comb electrode facing the mover comb electrode, the comb teeth of the mover comb electrode facing the stator comb electrode, and the surface of the mover comb electrode facing away from the comb teeth being connected to the electrode plate via a cantilever beam. The step of providing the base plate includes: Provide substrate; A metal layer is formed on one side of the substrate, and the metal layer has slits; A planarization layer and a passivation layer are sequentially formed on the side of the metal layer opposite to the substrate to obtain the base plate; The step of forming a driving layer on one side of the base plate includes: A sacrificial layer is formed on the side of the passivation layer opposite to the substrate; Using a patterning process, the driving layer is formed on the side of the sacrificial layer opposite to the substrate. The driving layer includes the electrode plate, the mover comb electrode, the stator comb electrode, and the cantilever beam. The sacrificial layer is etched to form a support structure and the gap. The support structure includes a first support pattern and a second support pattern. The first support pattern is located between the ridge of the stator comb electrode and the base plate, and is used to fix the ridge of the stator comb electrode to the base plate. The second support pattern is located between the two ends of the ridge of the mover comb electrode and the base plate, and is used to fix the two ends of the ridge of the mover comb electrode to the base plate. The gap is located at least between the electrode plate and the base plate, between the cantilever beam and the base plate, between the middle area of ​​the ridge of the mover comb electrode and the base plate, and between the comb teeth of the mover comb electrode and the base plate.

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