Microstrip filter, electronic device, and in-building distribution system

Abstract

A microstrip filter, comprising: a first substrate (11) and a second substrate (12) arranged opposite to each other, and a dielectric layer (13) located between the first substrate (11) and the second substrate (12). The first substrate (11) comprises: a first base (110), and a patch array provided on the side of the first base (110) close to the dielectric layer (13). The second substrate (12) comprises: a second base (120), a microstrip line (121) provided on the side of the second base (120) close to the dielectric layer (13), and a grounding layer (122) provided on the side of the second base (120) away from the microstrip line (121). The microstrip line (121) comprises: a major transmission line (1211) and at least one stub (1212), the orthographic projection of the stub (1212) of the microstrip line (121) and the orthographic projection of the patch array on the first base (110) overlapping each other. The dielectric layer (13) is configured to regulate the resonant frequency between the patch array and the microstrip line (121) when a voltage is applied to patches (111) in the patch array.

Description

Microstrip filters, electronic equipment and indoor distribution systems Technical Field

[0001] This article relates to but is not limited to the field of communication technology, in particular to a microstrip filter, electronic equipment and indoor distribution system. Background Art

[0002] A filter is an electronic device or circuit that selectively passes or blocks signals within a specific frequency range. It is widely used in electronics, communications, and signal processing. The rapid development of modern communications technology is driving increasing demands for integration, low power consumption, and multifunctionality. The need for integrated and low-cost filter design is a key development imperative.

[0003] Summary of the Invention

[0004] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0005] This embodiment provides a microstrip filter, an electronic device, and an indoor distribution system.

[0006] On the one hand, this embodiment provides a microstrip filter, comprising: a first substrate and a second substrate disposed opposite each other, and a dielectric layer located between the first and second substrates. The first substrate comprises: a first substrate, and a patch array disposed on a side of the first substrate close to the dielectric layer. The second substrate comprises: a second substrate, a microstrip line disposed on a side of the second substrate close to the dielectric layer, and a ground layer disposed on a side of the second substrate away from the microstrip line. The microstrip line comprises: a main transmission line and at least one branch. The branch of the microstrip line overlaps with the patch array on the orthographic projection of the first substrate. The dielectric layer is configured to adjust the resonant frequency between the patch array and the microstrip line when a voltage is applied to a patch of the patch array.

[0007] In some exemplary embodiments, the microstrip line includes a plurality of branches, and the plurality of branches are symmetrically arranged with respect to the main transmission line.

[0008] In some exemplary embodiments, the microstrip line includes eight branches, and the eight branches are symmetrically arranged with respect to the main transmission line.

[0009] In some exemplary embodiments, the microstrip line includes a plurality of stubs, and the plurality of stubs are connected to the same side of the main transmission line.

[0010] In some exemplary embodiments, the microstrip line includes four stubs, and the four stubs are connected to the same side of the main transmission line.

[0011] In some exemplary embodiments, an extension direction of the branch of the microstrip line is perpendicular to an extension direction of the main transmission line.

[0012] In some exemplary embodiments, the patch array includes multiple types of patches, and patches of the same type have the same shape and size; one type of patch corresponds to one tunable center frequency.

[0013] In some exemplary embodiments, the orthographic projection of at least one branch of the microstrip line on the first substrate overlaps with the orthographic projections of multiple patches of the patch array on the first substrate, and the multiple patches overlapping with the same branch are of different types.

[0014] In some exemplary embodiments, a plurality of patches whose orthographic projections on the first substrate overlap with the same branch are arranged in ascending order of size in a direction away from the main transmission line.

[0015] In some exemplary embodiments, at least one type of patch has a slotted region, and an orthographic projection of the slotted region on the first substrate overlaps with an orthographic projection of a branch of the microstrip line on the first substrate.

[0016] In some exemplary embodiments, the orthographic projection of the grooved region on the first substrate is a rectangle.

[0017] In some exemplary embodiments, the orthographic projection of at least one type of patch on the first substrate is a rectangle.

[0018] In some exemplary embodiments, the first substrate further includes: a plurality of driving electrode lines disposed on the first substrate, and a plurality of patches of the same type are connected to the same driving electrode line.

[0019] In some exemplary embodiments, the first substrate further includes: a first alignment layer located on a side of the patch array close to the dielectric layer; the second substrate further includes: a second alignment layer located on a side of the microstrip line close to the dielectric layer.

[0020] In some exemplary embodiments, the medium layer includes a liquid crystal layer.

[0021] On the other hand, this embodiment provides a driving method for a microstrip filter as shown above, including: applying voltage to at least one patch in a patch array, changing the dielectric constant of the dielectric layer between the at least one patch and the branch, so as to control the resonant frequency between the at least one patch and the microstrip line.

[0022] On the other hand, this embodiment provides an electronic device including the microstrip filter as described above.

[0023] On the other hand, this embodiment provides a room distribution system, including the microstrip filter as described above.

[0024] In some exemplary embodiments, a distributed indoor system includes: a distributed indoor signal source module, an intermediate module, and a distributed indoor antenna module; the intermediate module is connected between the distributed indoor signal source module and the distributed indoor antenna module. The distributed indoor antenna module includes a filter-mixing unit and multiple antennas, the filter-mixing unit being connected to the intermediate module and the multiple antennas, and the filter-mixing unit including at least one of the aforementioned microstrip filters.

[0025] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description.

[0026] Summary of the Figures

[0027] The accompanying drawings are used to provide a further understanding of the technical solution of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the technical solution of the present disclosure and do not constitute a limitation to the technical solution of the present disclosure.

[0028] FIG1 is a schematic structural diagram of a microstrip filter according to at least one embodiment of the present disclosure;

[0029] FIG2 is a schematic diagram of a partial cross-section along the Q-Q' direction in FIG1;

[0030] FIG3 is a schematic plan view of a first substrate according to at least one embodiment of the present disclosure;

[0031] FIG4 is a schematic plan view of a second substrate according to at least one embodiment of the present disclosure;

[0032] 5A and 5B are schematic diagrams showing simulation results of a microstrip filter according to at least one embodiment of the present disclosure;

[0033] FIG6 is another schematic diagram of a microstrip filter according to at least one embodiment of the present disclosure;

[0034] FIG7 is another schematic diagram of a microstrip filter according to at least one embodiment of the present disclosure;

[0035] FIG8 is another schematic diagram of a microstrip filter according to at least one embodiment of the present disclosure;

[0036] FIG9 is a schematic structural diagram of a room distribution system according to at least one embodiment of the present disclosure;

[0037] FIG10 is a schematic diagram of a room-distributed signal source module according to at least one embodiment of the present disclosure;

[0038] FIG11 is another schematic diagram of a room-distributed signal source module according to at least one embodiment of the present disclosure;

[0039] FIG12 is a schematic diagram of a filtering and mixing unit of a room-based antenna module according to at least one embodiment of the present disclosure;

[0040] FIG13 is another schematic diagram of a filtering and mixing unit of a room-based antenna module according to at least one embodiment of the present disclosure;

[0041] FIG14 is a schematic diagram of an electronic device according to at least one embodiment of the present disclosure.

[0042] Details

[0043] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The embodiments can be implemented in a variety of different forms. A person skilled in the art can easily understand that the method and content can be transformed into one or more forms without departing from the purpose and scope of the present disclosure. Therefore, the present disclosure should not be interpreted as being limited to the contents described in the following embodiments. In the absence of conflict, the embodiments of the present disclosure and the features in the embodiments can be combined with each other in any way.

[0044] In the drawings, the size of one or more components, layer thicknesses, or regions may be exaggerated for clarity. Therefore, one embodiment of the present disclosure is not necessarily limited to these dimensions, and the shapes and sizes of various components in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate idealized examples, and one embodiment of the present disclosure is not limited to the shapes or values ​​shown in the drawings.

[0045] In the present disclosure, ordinal numbers such as "first," "second," and "third" are provided to avoid confusion among constituent elements, and are not intended to limit the number. In the present disclosure, "plurality" refers to a number of two or more.

[0046] In this disclosure, for convenience, words and phrases indicating orientation or positional relationships, such as "middle," "upper," "lower," "front," "back," "vertical," "horizontal," "top," "bottom," "inside," and "outside," are used to illustrate the positional relationships of constituent elements with reference to the accompanying drawings. This is merely for the convenience of describing this specification and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation of this disclosure. The positional relationships of constituent elements are appropriately changed according to the direction in which the constituent elements are described. Therefore, the words and phrases are not limited to those described in the specification and can be appropriately replaced according to the circumstances.

[0047] In this disclosure, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct connections, indirect connections through intermediaries, or internal communication between two components. Those skilled in the art will understand the meaning of these terms in this disclosure based on the specific circumstances.

[0048] In this disclosure, "electrically connected" includes components connected together via an element having some electrical function. There are no particular limitations on the "element having some electrical function" as long as it enables transmission of electrical signals between the connected components. Examples of "element having some electrical function" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other elements having one or more functions.

[0049] In this disclosure, "parallel" refers to a state where the angle formed by two straight lines is greater than -10° and less than 10°, and thus includes a state where the angle is greater than -5° and less than 5°. Furthermore, "perpendicular" refers to a state where the angle formed by two straight lines is greater than 80° and less than 100°, and thus includes a state where the angle is greater than 85° and less than 95°.

[0050] In this disclosure, the terms "approximately" and "substantially" are used without strict boundaries, allowing for numerical values ​​within the range of process and measurement errors. In this disclosure, "same" can include both completely identical and substantially identical values, and "substantially identical" means that the numerical values ​​differ by less than 10%.

[0051] This embodiment provides a microstrip filter, an electronic device, and an indoor distributed system, which can realize integrated and low-cost filter design.

[0052] This embodiment provides a microstrip filter, comprising: a first substrate and a second substrate arranged relative to each other, and a dielectric layer located between the first substrate and the second substrate. The first substrate comprises: a first substrate, a patch array arranged on a side of the first substrate close to the dielectric layer. The second substrate comprises: a second substrate, a microstrip line arranged on a side of the second substrate close to the dielectric layer, and a ground layer arranged on a side of the second substrate away from the microstrip line. The microstrip line comprises: a main transmission line and at least one branch. The branch of the microstrip line overlaps with the orthographic projection of the patch array on the first substrate. The dielectric layer is configured to adjust the resonant frequency between the patch array and the microstrip line when a voltage is applied to the patches of the patch array.

[0053] The microstrip filter provided in this embodiment is configured to overlap the branches of the microstrip line with the orthographic projection of the patch array on the first substrate, and to apply voltage to the patches in the patch array to change the dielectric constant of the dielectric layer, thereby controlling the resonant frequency between the patches with overlapping orthographic projections and the branches of the microstrip line, thereby achieving a bandpass effect that allows the corresponding frequency signal to pass through.

[0054] In some exemplary embodiments, the dielectric layer may include a liquid crystal layer. When the dielectric layer includes a liquid crystal layer, the adjustable dielectric constant of the liquid crystal material at different voltages can be utilized to control the frequency response between the patch array and the microstrip line. In other examples, the dielectric layer may include at least one of the following: lead zirconate titanate (PZT) film, barium calcium zirconate titanate (BZT) film, barium strontium titanate (BST) film, etc. This embodiment is not limited to this.

[0055] In some exemplary embodiments, a microstrip line may include multiple branches, and the multiple branches may be symmetrically arranged about the main transmission line. For example, a microstrip line may include eight branches, and the eight branches may be symmetrically arranged about the main transmission line. In this example, by employing a symmetrical arrangement of branches, the radiation characteristics generated by the branches on both sides of the main transmission line and the patch array can be offset, thereby preventing leakage of electromagnetic radiation and interference with external devices.

[0056] In some exemplary embodiments, the microstrip line may include multiple branches, and the multiple branches may be connected to the same side of the main transmission line. For example, the microstrip line may include four branches, and the four branches may be connected to the same side of the main transmission line. This example uses an asymmetric layout of branches to limit the radiation of electromagnetic waves while ensuring that the distance between the patch array and the ground layer is sufficiently close and the thickness of the first substrate and the second substrate is relatively small (e.g., much less than 1 / 10 of the wavelength).

[0057] In some exemplary embodiments, the patch array may include multiple types of patches, and patches of the same type may have the same shape and size. The number of patch types corresponds to the number of tunable center frequencies of the microstrip filter. In this example, patches of the same type may correspond to the same resonant center frequency. By providing multiple types of patches, this example can support the microstrip filter to achieve different frequency responses. By applying voltage to one or more types of patches, the resonant frequency between the patch and the microstrip line is controlled to achieve the desired filter effect.

[0058] In some exemplary embodiments, the orthographic projection of at least one branch of the microstrip line on the first substrate may overlap with the orthographic projections of multiple patches of the patch array on the first substrate, and the multiple patches overlapping the same branch may be of different types. In some examples, the multiple patches that overlap with the orthographic projection of the same branch on the first substrate may be arranged in ascending order of size, away from the main transmission line. The arrangement of the patch array in this example can help ensure the effectiveness of the microstrip filter.

[0059] In some exemplary embodiments, at least one type of patch may have a slotted region. The orthographic projection of the slotted region onto the first substrate may overlap with the orthographic projection of a microstrip line branch onto the first substrate. In some examples, the orthographic projection of the slotted region onto the first substrate may be rectangular. For example, the orthographic projection of at least one type of patch onto the first substrate may be a rectangular ring. By providing slotted regions on the patches in this example, the radiating side length of the patch that overlaps with the branch can be increased, thereby reducing the size of the patch array.

[0060] In some exemplary embodiments, the first substrate may further include: a plurality of drive electrode lines arranged on the first substrate, and a plurality of patches of the same type are connected to the same drive electrode line. Since whether a voltage is applied to the patch will affect the on-off of the corresponding frequency, this example uses the same drive voltage control for patches of the same type to make the frequency band of the response frequency narrower and achieve a better on-off effect. However, this embodiment is not limited to this. In other examples, multiple patches of the same type can be connected to different drive electrode lines, and by applying different voltages to patches of the same type, the isolation degree can be easily weakened.

[0061] The solution of this embodiment is illustrated below through some examples.

[0062] Figure 1 is a schematic diagram of the structure of a microstrip filter of at least one embodiment of the present disclosure. Figure 2 is a schematic diagram of a partial cross-section along the Q-Q' direction in Figure 1. In some examples, as shown in Figures 1 and 2, the microstrip filter of this example may include: a first substrate 11 and a second substrate 12 arranged opposite to each other, and a dielectric layer 13 located between the first substrate 11 and the second substrate 12. In some examples, the dielectric layer 13 may be a liquid crystal layer, including a liquid crystal material. The first substrate 11 and the second substrate 12 may be arranged in a box to form a liquid crystal box, and the dielectric layer 13 may be arranged in the liquid crystal box. However, this embodiment is not limited to this. In other examples, the dielectric layer may include at least one of the following: a lead zirconate titanate (PZT) film, a barium calcium zirconate titanate (BZT) film, a barium strontium titanate (BST) film, etc.

[0063] In some examples, as shown in Figure 2, a support structure 14 can be provided between the first substrate 11 and the second substrate 12. The support structure 14 can be roughly an annular structure surrounding the periphery of the first substrate 11 and the second substrate 12. The support structure 14 may include a sealing glue and a spacer (or isolation column). By providing a support structure, a cavity can be formed between the first substrate 11 and the second substrate 12, and a liquid crystal layer located between the first substrate 11 and the second substrate 12 can be formed by pouring liquid crystal material into the cavity. However, this embodiment is not limited to this. In this example, by providing a support structure, the gap between the first substrate and the second substrate can be maintained, which is beneficial to maintaining the uniformity of the liquid crystal layer and preventing the collapse of the cavity from affecting the thickness uniformity of the liquid crystal layer.

[0064] FIG3 is a schematic plan view of a first substrate according to at least one embodiment of the present disclosure. In some examples, as shown in FIG1 to FIG3 , the first substrate 11 may include: a first substrate 110, and a patch array disposed on the first substrate 110. The patch array may be located on a side of the first substrate 110 adjacent to the dielectric layer 13. The patch array may include: a plurality of patches 111 arranged in an array. The plurality of patches 111 arranged along a first direction X may be referred to as a row of patches, and the plurality of patches 111 arranged along a second direction Y may be referred to as a column of patches. The first direction X intersects the second direction Y. For example, the first direction X may be perpendicular to the second direction Y.

[0065] In some examples, as shown in FIG3 , the first substrate 11 may further include: a plurality of drive electrode lines 113 a and 113 b located on the first substrate 110 . The plurality of patches 111 of the patch array may be electrically connected to the plurality of drive electrode lines. For example, the plurality of patches 111 and the plurality of drive electrode lines 113 a and 113 b may be electrically connected in a one-to-one correspondence. For example, the patches 111 and the drive electrode lines to which they are connected may be an integrated structure connected to each other.

[0066] In some examples, as shown in FIG3 , the first substrate 11 may further include: a plurality of drive transmission lines 114a and 114b located on the first substrate 110 and extending along the first direction X. The plurality of drive transmission lines 114a and 114b may be arranged in the edge areas on both sides of the patch array in the second direction Y. The plurality of drive transmission lines 114a and the plurality of drive electrode lines 113a may be electrically connected, and the plurality of drive transmission lines 114b and the plurality of drive electrode lines 113b may be electrically connected. For example, the plurality of drive electrode lines and the plurality of drive transmission lines may be electrically connected one-to-one. The drive transmission lines 114a and 114b may be configured to receive voltage signals transmitted by an external controller. The drive transmission lines and the connected drive electrode lines may be an integrated structure connected to each other. However, this embodiment is not limited to this. In other examples, the drive transmission lines may be omitted, and the drive electrode lines may extend directly outward and receive voltage signals transmitted by the controller.

[0067] In some examples, the patch array may include: multiple types of patches. Patches of the same type may have the same shape and size, and at least one of the sizes and shapes of patches of different types may be different. For example, patches of different types have the same shape and different sizes, or patches of different types have different shapes and sizes. One type of patch may correspond to a resonant center frequency. The number of patch types corresponds to the number of resonant center frequencies. Different types of patches correspond to different resonant center frequencies. This example is illustrated by taking three types of patches (such as the first type patch 111a, the second type patch 111b, and the third type patch 111c shown in Figure 3) as an example. The microstrip filter of this example can correspond to three resonant center frequencies.

[0068] In some examples, each type of patch can have a slotted area. For example, a first-type patch 111a can have a first slotted area 1110a, a second-type patch 111b can have a second slotted area 1110b, and a third-type patch 111c can have a third slotted area 1110c. The orthographic projections of the first slotted area 1110a, the second slotted area 1110b, and the third slotted area 1110c on the first substrate 110 can each be substantially rectangular. The sizes of the first slotted area 1110a, the second slotted area 1110b, and the third slotted area 1110c can increase in sequence.

[0069] In some examples, as shown in Figure 3, the shapes of the positive projections of the first type patch 111a, the second type patch 111b and the third type patch 111c on the first substrate 1110 can all be rectangular rings, the size of the first type patch 111a can be smaller than the size of the second type patch 111b, and the size of the second type patch 111b can be smaller than the size of the third type patch 111c.

[0070] Figure 4 is a schematic plan view of a second substrate according to at least one embodiment of the present disclosure. In some examples, as shown in Figures 1 to 4, the second substrate 12 may include: a second substrate 120, a microstrip line 121 disposed on opposite sides of the second substrate 120, and a ground layer 122. The microstrip line 121 may be located on a side of the second substrate 120 close to the dielectric layer 13, and the ground layer 122 may be located on a side of the second substrate 120 away from the dielectric layer 13. The ground layer 122 may be a solid metal layer, and the orthographic projection of the ground layer 122 on the second substrate 120 may cover the orthographic projection of the microstrip line 121 on the second substrate 120. In this example, a microstrip transmission structure can be formed using the microstrip line 121, the second substrate 120, and the ground layer 122.

[0071] In some examples, as shown in FIG4 , the microstrip line 121 may include a main transmission line 1211 and at least one branch 1212 . The orthographic projection of the main transmission line 1211 on the second substrate 120 may be a strip-shaped structure extending along the first direction X. One end of the main transmission line 1211 may be connected to the first port 15 a, and the other end of the main transmission line 1211 may be connected to the second port 15 b. The first port 15 a and the second port 15 b may be the input port and the output port of the microstrip filter. This embodiment does not limit the type and configuration of the first and second ports.

[0072] In some examples, the microstrip line 121 may include a plurality of branches 1212, for example, eight branches 1212. The plurality of branches 1212 and the main transmission line 1211 may be an integral structure connected to each other. The shape of the orthographic projection of a single branch 1212 on the second substrate 120 may be approximately a strip structure extending along the second direction Y. The extension direction of the branch 1212 may be perpendicular to the extension direction of the main transmission line 1211. The eight branches 1212 in this example may be symmetrically arranged with respect to the main transmission line 1211. The sizes of the eight branches 1212 may be approximately the same. The spacing between adjacent branches 1212 may be approximately the same. The microstrip line 121 may be approximately symmetrical with respect to the midline of the first direction X, and may also be approximately symmetrical with respect to the midline of the second direction Y. In this example, the branches of the microstrip line may be arranged symmetrically. Due to the bilaterally symmetrical design, the surface currents of the patch array may be directed in opposite directions, so that the generated radiation characteristics cancel each other out, thereby avoiding interference with external devices.

[0073] In some examples, the orthographic projection of each branch 1212 of the microstrip line 121 on the first substrate 110 may overlap with the orthographic projection of the patch array on the first substrate 110, and the orthographic projection of the main transmission line 1211 and the patch array on the first substrate 110 may not overlap. The patch array can be arranged roughly symmetrically about the main transmission line 1211. The patch array of this example can be arranged in six rows and four columns. The main transmission line 1211 can be arranged in three rows and four columns on one side of the second direction Y, and can also be arranged in three rows and four columns on the side opposite to the second direction Y. The multiple patches in the same row of patches have the same size, and the multiple patches in a row of patches belong to the same type; the multiple patches in the same column of patches can have different sizes, and the multiple patches in a column of patches belong to different types.

[0074] In some examples, the orthographic projection of each branch 1212 on the first substrate 110 overlaps with the orthographic projection of a column of patches (including three different types of patches, namely, the first type patch 111a, the second type patch 111b and the third type patch 111c) on the first substrate 110. The three patches that overlap with the orthographic projection of each branch 1212 on the first substrate 110 can be arranged in order from small to large in size in a direction away from the main transmission line 1211. The first type patch 111a, the second type patch 111b and the third type patch 111c located in the same column can be aligned in the second direction Y, and the center lines of the three patches along the first direction X can coincide. The center lines of the three patches along the first direction X can roughly coincide with the center lines of the overlapping branches 1212 along the first direction X. However, this embodiment is not limited to this. In other examples, a row of patches that overlap with the orthographic projection of the branch on the first substrate can be arranged in descending order of size away from the main transmission line. In other examples, multiple patches of the patch array can be arranged in a nested manner. For example, a first type of patch can be arranged within the second slot region of a second type of patch, or a second type of patch can be arranged within the third slot region of a third type of patch.

[0075] In some examples, as shown in FIG2 , the first substrate 11 may further include a first alignment layer 112 located on the side of the patch array close to the dielectric layer 13. The second substrate 12 may further include a second alignment layer 123 located on the side of the microstrip line 121 close to the dielectric layer 13. In this example, by providing the first and second alignment layers, the liquid crystal molecules in the dielectric layer can be aligned so that the liquid crystal molecules are arranged in a certain direction.

[0076] In some examples, the microstrip filter of this example uses a double-sided metal process on the second substrate to form a microstrip transmission structure. The liquid crystal molecules in the liquid crystal layer are anisotropic materials with different dielectric constants along the long axis and short axis directions. When a deflection voltage is applied to both ends of the liquid crystal molecules, the liquid crystal molecules will deflect, and the dielectric constant of the liquid crystal material will change with the deflection of the liquid crystal. By applying a voltage to the patches of the patch array, the liquid crystal deflection can be used to adjust the resonant frequency between the patch and the overlapping microstrip transmission structure. The dielectric constant of the liquid crystal molecules in the liquid crystal layer corresponding to each patch and the microstrip transmission structure can be independently controlled and changed. When a voltage is applied to the corresponding patch through the driving electrode line, the liquid crystal deflection can be used to achieve resonance between the patch and the overlapping microstrip transmission structure at a non-center frequency, allowing the center frequency signal corresponding to the patch to pass, forming a bandpass effect; when no voltage is applied to the patch through the driving electrode line, the patch and the overlapping microstrip transmission structure resonate at the center frequency, causing the center frequency signal corresponding to the patch to be turned off, forming a bandstop effect. The liquid crystal layer of this example is configured to control the on and off of the resonant center frequency corresponding to the patch. In some examples, the number of patch types can determine the number of tunable center frequencies of the microstrip filter. One type of patch corresponds to one tunable center frequency, and different types of patches can correspond to different center frequencies. In some examples, the number of branches of the microstrip line can determine the bandwidth corresponding to the tunable center frequency. The more branches a microstrip line has, the more patches of the same type that overlap with the branches, which is conducive to increasing the bandwidth corresponding to the center frequency corresponding to the patch of this type and improving the filtering effect. The fewer branches a microstrip line has, the fewer patches of the same type that overlap with the branches, which reduces the bandwidth corresponding to the center frequency corresponding to the patch of this type.

[0077] In some examples, the driving voltage applied to the patches of the patch array may depend on the material and thickness of the dielectric layer. The driving voltage may be less than 30 V. For example, if the dielectric layer is a liquid crystal layer, the driving voltage may be less than or equal to 8 V.

[0078] Figures 5A and 5B are schematic diagrams of simulation results for a microstrip filter according to at least one embodiment of the present disclosure. Figure 5A shows the simulation results after voltage is applied to the first type of patch in the patch array of the microstrip filter shown in Figure 1. Figure 5B shows the simulation results after no voltage is applied to the first type of patch in the patch array of the microstrip filter shown in Figure 1.

[0079] In some examples, the length of the first type of patch can be 10.5 millimeters (mm) and the width can be 5 mm. The length and width of the first slot region of the first type of patch can be 6.4 mm and 0.8 mm, respectively. The first type of patch can correspond to 2.5 GHz to 2.6 GHz. The length of the second type of patch can be 23 mm and the width can be 8 mm. The length and width of the second slot region of the second type of patch can be 10 mm and 0.8 mm, respectively. The second type of patch can correspond to 0.74 GHz to 0.76 GHz. The length of the third type of patch can be 23 mm and the width can be 10 mm. The length and width of the third slot region of the third type of patch can be 20 mm and 0.8 mm, respectively. The third type of patch can correspond to 1.34 GHz to 1.38 GHz. The width of the main transmission line of the microstrip line (i.e., the length along the second direction Y) can be approximately 1.6 mm, the width of the branch (i.e., the length along the first direction X) can be approximately 4 mm, the length of the branch (i.e., the length along the second direction Y) can be approximately 72 mm, and the spacing between adjacent branches can be approximately 28 mm. The thickness of the liquid crystal layer may be approximately 20 micrometers (um).

[0080] In some examples, Figures 5A and 5B provide a comparative explanation of whether the 2.5GHz to 2.6GHz band can pass through. Figure 5A shows a situation where voltage is applied to the first type of patch, and no voltage is applied to the second type of patch and the third type of patch. Figure 5B shows a situation where no voltage is applied to the first type of patch, the second type of patch and the third type of patch. It can be seen from Figure 5A that when voltage is applied to the first type of patch, signals from 2.5GHz to 2.6GHz can pass through, forming a bandpass effect. It can be seen from Figure 5B that when the voltage applied to the first type of patch is removed, the loss at 2.5GHz to 2.6GHz reaches 30dB, which is equivalent to this part of the signal not passing through, forming a bandstop effect. This example can achieve the purpose of signal on and off by controlling the voltage applied to the corresponding type of patch. In some examples, the number of patch types can be reasonably designed according to the number of frequencies to be reused.

[0081] The following is an illustrative explanation of the preparation process of a microstrip filter. The "patterning process" mentioned in the present disclosure includes processes such as coating photoresist, mask exposure, development, etching, and stripping photoresist for metal materials, inorganic materials, or transparent conductive materials, and includes processes such as coating organic materials, mask exposure, and development for organic materials. Deposition can be carried out by any one or more of sputtering, evaporation, and chemical vapor deposition, coating can be carried out by any one or more of spraying, spin coating, and inkjet printing, and etching can be carried out by any one or more of dry etching and wet etching, and the present disclosure does not limit this. "Thin film" refers to a layer of thin film made by deposition, coating, or other processes on a substrate of a certain material. If the "thin film" does not require a patterning process during the entire production process, the "thin film" can also be called a "layer". If the "thin film" requires a patterning process during the entire production process, it is called a "thin film" before the patterning process and a "layer" after the patterning process. The "layer" after the patterning process contains at least one "pattern".

[0082] As used herein, "A and B are disposed in the same layer" means that A and B are formed simultaneously through the same patterning process. In exemplary embodiments of the present disclosure, "the orthographic projection of A includes the orthographic projection of B" means that the boundary of the orthographic projection of B falls within the boundary of the orthographic projection of A, or that the boundary of the orthographic projection of A overlaps with the boundary of the orthographic projection of B.

[0083] In some exemplary embodiments, a process for preparing a microstrip filter may include the following operations.

[0084] (1) Prepare a first substrate. In some examples, a routing layer and a first conductive layer are sequentially formed on the first substrate. For example, a routing film is coated on the first substrate, and a routing layer is formed by a patterning process; then, a first conductive film is coated to form a first conductive layer. The first conductive layer can be made of a metal material with good conductivity, such as copper (Cu). The first conductive layer can include a patch array. The routing layer can be made of a metal material or a transparent conductive material, such as indium tin oxide (ITO). The routing layer can include a plurality of drive electrode lines, or a plurality of drive electrode lines and a plurality of drive transmission lines.

[0085] In some examples, a first alignment film may be coated on the first substrate on which the aforementioned pattern is formed, the first alignment film may be cured, and the cured first alignment film may be aligned using an alignment technique to obtain a transparent first alignment layer. The first alignment layer may cover the first conductive layer and the wiring layer.

[0086] (2) Prepare a second substrate. In some examples, a second conductive layer and a ground layer are formed on opposite sides of the second substrate. The second conductive layer can be made of a metal material with good conductivity, such as copper (Cu). The second conductive layer can include a microstrip line. A ground layer can be formed on a side of the second substrate away from the second conductive layer by plating. The orthographic projection of the ground layer on the second substrate can include the orthographic projection of the second conductive layer on the second substrate.

[0087] In some examples, a second alignment film may be coated on the second substrate on which the aforementioned pattern is formed, the second alignment film may be cured, and the cured second alignment film may be aligned using an alignment technique to obtain a transparent second alignment layer. The second alignment layer may cover the second conductive layer.

[0088] In some examples, alignment techniques may include rubbing alignment and ultraviolet light alignment. These techniques can form grooves on the surface of the first alignment layer to align the liquid crystal molecules, causing them to align in a specific direction. The first alignment film may be made of polyimide, polyamide, polyethylene, polystyrene, or polyvinyl alcohol. However, this embodiment is not limited to this.

[0089] In some examples, the first and second substrates can be rigid substrates, such as glass substrates. Using rigid substrates to form the liquid crystal cell allows for precise control of its thickness, ensuring uniform thickness. Furthermore, microstrip filters based on glass substrates are easy to manufacture in large quantities, reducing device complexity and cost.

[0090] (3) Align the first substrate and the second substrate to prepare a liquid crystal box.

[0091] In some examples, a sealant is applied around the perimeter of the first or second substrate, the first and second substrates are aligned, and the sealant is cured to form a support structure between the first and second substrates. The first and second substrates, along with the support structure, form a cavity. Multiple filling ports can be arranged sequentially on the support structure, through which liquid crystal material is poured to form a liquid crystal layer serving as the dielectric layer.

[0092] In this example, the microstrip line branches and patches form the upper and lower electrodes that control the operation of the liquid crystal layer. Leveraging the electrically tunable dielectric properties of the liquid crystal material, the filter's resonant frequency can be easily adjusted. To adjust the filter's resonant frequency, a driving voltage is applied through the patches, creating a voltage difference between the patches and branches. This voltage difference alters the arrangement of the liquid crystal molecules, adjusting the resonant frequency.

[0093] The microstrip filter provided in this example can be designed on a glass substrate using a semiconductor thin film process to design multiple adjustable units (i.e., patches and branch structures sandwiching a liquid crystal layer) with adjustable resonant frequencies. The resonant frequency of the adjustable units can be controlled by applying voltage to achieve different frequency responses of the same adjustable unit, and the filter effect can be achieved by combining and controlling multiple adjustable units. Because the adjustable units in this example can control different frequency responses by applying voltage, different voltage application combinations can be used to control and achieve different filtering effects, thereby achieving the purpose of simplifying the design and reducing costs.

[0094] FIG6 is another schematic diagram of a microstrip filter according to at least one embodiment of the present disclosure. In some examples, as shown in FIG6 , the patch array can be symmetrically arranged about the main transmission line of microstrip line 121. In the patch array located on one side of the main transmission line, patches of the same type can be electrically connected to the same drive electrode line 113a or 113b. For example, a row of patches of the same type can be electrically connected to the same drive electrode line 113a or 113b. The remaining description of the microstrip filter of this example can refer to the description of the aforementioned embodiment and is not repeated here.

[0095] In this example, since the presence or absence of applied voltage affects the on / off isolation of the corresponding frequency, applying a uniform voltage to patches of the same type can narrow the frequency band of the response frequency, resulting in a better on / off isolation. However, this embodiment is not limited to this. In other examples, patches of the same type can be applied with different voltages to widen the frequency band of the response frequency and weaken the on / off isolation.

[0096] FIG7 is another schematic diagram of a microstrip filter according to at least one embodiment of the present disclosure. In some examples, as shown in FIG7 , the orthographic projection of the patch 111 of the patch array on the first substrate may be a rectangle. The patch array of this example may include three types of patches, and the orthographic projections of the three types of patches on the substrate may all be rectangular and of different sizes. Patches of the same type may be electrically connected to the same drive electrode line 113a or 113b. For example, a row of patches of the same type may be electrically connected to the same drive electrode line 113a or 113b. The remaining description of the microstrip filter of this example can refer to the description of the aforementioned embodiment, so it will not be repeated here.

[0097] In this example, when the area of ​​the microstrip filter is not limited, a solid patch can be used to achieve a filtering effect.

[0098] Figure 8 is another schematic diagram of a microstrip filter according to at least one embodiment of the present disclosure. In some examples, as shown in Figure 8 , microstrip line 121 may include four branches, each connected to the same side of the main transmission line. The patch array may include three rows and four columns. The remaining description of the microstrip filter in this example can be found in the description of the previous embodiment and is not repeated here.

[0099] In this example, the branches of the microstrip line can adopt an asymmetric structure with respect to the main transmission line. While ensuring that the distance between the patch array and the ground layer is close enough and the thickness of the first substrate and the second substrate is small (for example, much less than 1 / 10 wavelength), the radiation of electromagnetic waves can be limited.

[0100] This embodiment also provides a microstrip filter driving method, applicable to the microstrip filter described above. The driving method of this example may include applying a voltage to at least one patch in the patch array to change the dielectric constant of a dielectric layer between the patch and the branch, thereby controlling the resonant frequency between the at least one patch and the microstrip line.

[0101] In some examples, the patch array includes multiple types of patches. By applying voltage to multiple patches of the same type, the signal corresponding to the resonant center frequency corresponding to the patch of that type can pass through, forming a bandpass effect. By controlling the combination of whether voltage is applied to multiple types of patches, the desired filtering effect can be achieved. The control unit (for example, provided with a control program) can provide a voltage signal to the corresponding patch by driving the electrode line, and control the resonant frequency by controlling the voltage applied to the corresponding patch to achieve the desired filtering effect.

[0102] Regarding the driving method of the microstrip filter of this embodiment, reference can be made to the description of the aforementioned embodiment, and thus will not be repeated here.

[0103] This embodiment also provides a room distribution system, including the microstrip filter as described above.

[0104] In some cases, with the development and maturity of 5G technology, indoor users are increasingly demanding high-bandwidth transmission. Millimeter-wave digital indoor distribution systems (DASs) have yet to be commercialized due to technical and cost constraints. Traditional, relatively mature distributed antenna systems (DASs) are unable to carry higher data volumes. Reusing and improving traditional DASs has become a preferred solution. The two mainstream technical approaches are active frequency conversion DAS and passive frequency conversion DAS. Both approaches divide and convert a 5G signal, then convert it back after transmission. Different polarizations are used to distinguish it from the original frequency, achieving multiple-input, multiple-output (MIMO) and expanding capacity. However, any frequency conversion solution involves frequency conversion, matching, and filtering components, typically using discrete devices, low-temperature co-fired ceramics (LTCCs), and dielectric filters. This leads to a series of issues such as customized design, high cost, and large size.

[0105] The indoor distributed system of this embodiment can adopt the microstrip filter provided by the aforementioned embodiment. The resonant frequency can be controlled by applying voltage, and the filter effect can be achieved by combined control of the patches that require applied voltage. Since the control of the patches that require applied voltage can be controlled by program, different filtering functions can be achieved. The indoor distributed system of this embodiment can simplify the complexity of system design and reduce system modification costs by utilizing the aforementioned microstrip filter.

[0106] The following is an example of the room distribution system in this example.

[0107] Figure 9 is a structural diagram of a distributed indoor system of at least one embodiment of the present disclosure. In some examples, as shown in Figure 9, the distributed indoor system of this example may include: a distributed indoor signal source module 31, an intermediate module 32, and a distributed indoor antenna module 33. The distributed indoor signal source module 31 can be configured to provide a wireless signal as an input to the system. For example, the wireless signal provided by the distributed indoor signal source module 31 may include: a radio frequency signal RF1 (e.g., 900MHz), a radio frequency signal RF2 (e.g., 1800MHz / 2GHz / 2.3GHz / 2.6GHz), a local oscillator signal LO (e.g., 1100MHz), and an intermediate frequency signal IF (e.g., 1500MHz). Multiple wireless signals can be combined by a combiner and then connected to the intermediate module 32 through a cable.

[0108] In some examples, after receiving the wireless signal provided by the indoor signal source module 31 via a cable, the intermediate module 32 amplifies, distributes, and manages the wireless signal to achieve enhanced coverage and capacity in the indoor area. For example, the intermediate module 32 may include a power splitter, a feeder, and a coupler.

[0109] In some examples, the output signal of the intermediate module 32 can be provided to the indoor antenna module 33. The indoor antenna module 33 can provide high-quality wireless signal coverage and transmission in indoor environments. The indoor antenna module 33 can include a filtering and mixing unit and multiple antennas. The filtering and mixing unit can be connected to the intermediate module 32 and the multiple antennas. The filtering and mixing unit can filter and mix the output signal of the intermediate module 32 to generate multiple wireless signals, which are radiated through the multiple antennas.

[0110] Figure 10 is a schematic diagram of a room-based signal source module according to at least one embodiment of the present disclosure. In some examples, as shown in Figure 10, for the radio frequency signal RF1 and the radio frequency signal RF2 in the multi-channel wireless signal, after receiving the wireless signal, digital-to-analog conversion (DA, Digital to Analog), mixing, filtering and amplification processing can be performed in sequence, and then combined through a combiner. The original 2.6GHz signal in the signal source part is divided into two channels, one of which is transmitted using a 2.6GHz carrier and combined through digital-to-analog conversion, mixing, filtering and amplification processing; the other channel is converted into an intermediate frequency signal by mixing with the local oscillator signal after digital-to-analog conversion, mixing and filtering, and the intermediate frequency signal is combined with other wireless signals after filtering and amplification. The local oscillator signal is combined with other signals after amplification. The processing units for local oscillation, mixing, filtering and amplification of the room-based signal source module in this example can all be integrated inside the signal source device, and after being combined by the combiner, they are connected to the intermediate module through a cable.

[0111] FIG11 is another schematic diagram of the indoor signal source module of at least one embodiment of the present disclosure. In some examples, as shown in FIG11, the radio frequency signal RF1 and the radio frequency signal RF2 can be sequentially subjected to digital-to-analog conversion, mixing, filtering, and amplification processing before being combined and transmitted through a first combiner. The original 2.6 GHz signal in the signal source part can be divided into two paths. The first path uses a 2.6 GHz carrier for transmission and is combined with other radio frequency signals after digital-to-analog conversion, mixing, filtering, and amplification processing; the second path is converted into an intermediate frequency signal by mixing with the local oscillator signal after digital-to-analog conversion, mixing, and filtering. The intermediate frequency signal is filtered and amplified before being combined with other wireless signals through a second combiner. Among them, the mixing, filtering, and amplification processing units of the second 2.6 GHz signal can be separately packaged (such as the external unit indicated by the dotted box in FIG11) and connected to the signal source device integrated with the remaining radio frequency signals. In some examples, the filter in the external unit can use the microstrip filter provided in the aforementioned embodiment, which can simplify the design and reduce costs.

[0112] The indoor distributed system in this example splits the 2.6GHz signal from the source into two paths. One path still uses a 2.6GHz carrier for transmission, while the other path is converted into an intermediate frequency signal through a mixer for transmission. This eliminates the need to change the intermediate system, ensuring extremely low modification costs.

[0113] Figure 12 is a schematic diagram of the filtering and mixing unit of the indoor antenna module of at least one embodiment of the present disclosure. In some examples, as shown in Figure 12, the input port of the indoor antenna module can receive the output signal from the intermediate module. After receiving the signal, the indoor antenna module uses multiple filters (for example, including filters F1, F2, F3 and F4) to obtain the local oscillator (LO) signal, the intermediate frequency (IF) signal, the radio frequency (RF) signal RF1 and the radio frequency (RF2). In the filtering and mixing unit, the intermediate frequency (IF) signal can be re-converted to 2.6 GHz. The intermediate frequency (IF) signal is mixed with the output of the local oscillator (LO) signal after matching the balun (B1). The output of the mixer is processed by matching the balun (B3) and the filter (F5) to obtain a 2.6 GHz signal. The antenna can use different polarization radiation for the 2.6 GHz signal in the radio frequency signal RF2 and the 2.6 GHz signal obtained by frequency conversion, thereby achieving the purpose of MIMO multi-stream.

[0114] In some examples, at least one of the filters F1, F2, F3, F4 and F5 in the filtering and mixing unit shown in Figure 12 can adopt a microstrip filter as described in the above embodiment. The patches in the microstrip filter to which voltage needs to be applied can be controlled through program coding, and voltage can be applied to the corresponding patches to achieve different filtering effects.

[0115] In this example, all or part of the filters in the filtering and mixing units in the indoor distributed system adopt microstrip filters as in the above-mentioned embodiment. Only different codes are needed to control the filtering effect of the corresponding microstrip filters, which can reduce the types of filters required and the types of devices, thereby reducing the design complexity and modification cost of the system.

[0116] FIG13 is another schematic diagram of the filtering and mixing unit of the indoor antenna module of at least one embodiment of the present disclosure. In some examples, as shown in FIG13 , since additional devices such as filters and mixers are added to the indoor antenna module to convert the intermediate frequency signal, additional attenuation of the intermediate frequency signal will occur, resulting in an imbalance of the multi-input and multi-output signal. Therefore, an amplifier is added to amplify the frequency-converted signal after mixing the local oscillator signal LO and the intermediate frequency signal IF to ensure that the levels of the two 2.6 GHz signals (the original 2.6 GHz and the 2.6 GHz obtained by frequency conversion) are equivalent. However, this embodiment is not limited to this. In other examples, an attenuator can be added to attenuate the original 2.6 GHz signal to ensure that the levels of the two 2.6 GHz signals (the original 2.6 GHz and the 2.6 GHz obtained by frequency conversion) are equivalent.

[0117] In some examples, at least one of the filters F1, F2, F3, F4 and F5 in the filtering and mixing unit shown in Figure 13 can adopt a microstrip filter as described in the above embodiment. The patch to which the voltage needs to be applied in the microstrip filter can be controlled through program coding, and voltage can be applied to the corresponding patch to achieve different filtering effects.

[0118] The indoor distributed system in this example can reduce the types of devices required for the entire system by adopting the microstrip filter as described above, which is conducive to reducing the cost of system modification, and can also simplify the design and reduce the design complexity of the system.

[0119] Figure 14 is a schematic diagram of an electronic device according to at least one embodiment of the present disclosure. As shown in Figure 14, this embodiment provides an electronic device 91 comprising: a microstrip filter 910 as described in the previous embodiment; and a control unit. The control unit can control the voltage application mode of the patch array of microstrip filter 910 (i.e., which patches are voltage-applied and which are not voltage-applied), thereby controlling the resonant frequency between the corresponding patches and branches to achieve the corresponding filtering effect.

[0120] In some examples, the electronic device 91 may be any product or component with communication functionality, such as a mobile phone, a navigation device, a game console, a television (TV), a car stereo, a tablet computer, a personal multimedia player (PMP), or a personal digital assistant (PDA). However, this embodiment is not limited thereto.

[0121] The drawings in this disclosure only relate to the structures involved in this disclosure, and other structures can refer to the general design. In the absence of conflict, the embodiments of the present disclosure, that is, the features in the embodiments, can be combined with each other to obtain new embodiments. It should be noted that the above-mentioned embodiments or implementation methods are merely exemplary and not restrictive. Therefore, the present disclosure is not limited to the contents shown and described in detail herein. Various modifications, replacements or omissions can be made to the form and details of the implementation without departing from the scope of this disclosure.

Claims

1. A microstrip filter, comprising: A first substrate and a second substrate arranged opposite to each other, and a dielectric layer located between the first substrate and the second substrate; The first substrate comprises: a first substrate, and a patch array arranged on a side of the first substrate close to the dielectric layer; The second substrate comprises: a second substrate, a microstrip line arranged on a side of the second substrate close to the dielectric layer, and a ground layer arranged on a side of the second substrate away from the microstrip line; the microstrip line comprises: a main transmission line and at least one branch; The branches of the microstrip line overlap with the orthographic projection of the patch array on the first substrate, and the dielectric layer is configured to adjust the resonant frequency between the patch array and the microstrip line when a voltage is applied to the patches of the patch array.

2. The microstrip filter according to claim 1, wherein: The microstrip line includes a plurality of branches, and the plurality of branches are symmetrically arranged with respect to the main transmission line.

3. The microstrip filter according to claim 2, wherein: The microstrip line includes eight branches, and the eight branches are symmetrically arranged with respect to the main transmission line.

4. The microstrip filter according to claim 1, wherein: The microstrip line includes a plurality of branches, and the plurality of branches are connected to the same side of the main transmission line.

5. The microstrip filter according to claim 4, wherein: The microstrip line includes four branches, and the four branches are connected to the same side of the main transmission line.

6. The microstrip filter according to claim 1, wherein: An extension direction of the branch of the microstrip line is perpendicular to an extension direction of the main transmission line.

7. The microstrip filter according to any one of claims 1 to 6, wherein: The patch array includes multiple types of patches, and patches of the same type have the same shape and size; one type of patch corresponds to one tunable center frequency.

8. The microstrip filter according to claim 7, wherein: The orthographic projection of at least one branch of the microstrip line on the first substrate overlaps with the orthographic projections of multiple patches of the patch array on the first substrate, and the multiple patches overlapping the same branch belong to different types.

9. The microstrip filter according to claim 8, wherein: A plurality of patches that overlap with the orthographic projection of the same branch on the first substrate are arranged in order of size from small to large in a direction away from the main transmission line.

10. The microstrip filter according to claim 7, wherein: At least one type of patch has a slotted region, and an orthographic projection of the slotted region on the first substrate overlaps with an orthographic projection of a branch of the microstrip line on the first substrate.

11. The microstrip filter according to claim 10, wherein: The orthographic projection of the grooved area on the first substrate is a rectangle.

12. The microstrip filter according to claim 7, wherein: The orthographic projection of at least one type of patch on the first substrate is a rectangle.

13. The microstrip filter according to claim 7, wherein: The first substrate further includes: a plurality of driving electrode lines arranged on the first substrate, and a plurality of patches of the same type are connected to the same driving electrode line.

14. The microstrip filter according to claim 1, wherein: The first substrate further includes: a first alignment layer located on a side of the patch array close to the dielectric layer; the second substrate further includes: a second alignment layer located on a side of the microstrip line close to the dielectric layer.

15. The microstrip filter according to claim 1, wherein: The medium layer includes a liquid crystal layer.

16. A method for driving a microstrip filter according to any one of claims 1 to 15, comprising: A voltage is applied to at least one patch in the patch array to change the dielectric constant of the dielectric layer between the at least one patch and the branch, so as to control the resonant frequency between the at least one patch and the microstrip line.

17. An electronic device comprising the microstrip filter according to any one of claims 1 to 15.

18. A room distribution system, comprising the microstrip filter according to any one of claims 1 to 15.

19. The room distribution system according to claim 18, comprising: A room-divided signal source module, an intermediate module and a room-divided antenna module; the intermediate module is connected between the room-divided signal source module and the room-divided antenna module; The room-divided antenna module shown includes a filter-mixing unit and multiple antennas. The filter-mixing unit is connected to the intermediate module and the multiple antennas. The filter-mixing unit includes at least one of the microstrip filters mentioned above.

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