DIELECTRIC FILTER AND COMMUNICATION DEVICE

Abstract

 This application discloses a dielectric filter and a communication device, to effectively reduce loss of the dielectric filter. The dielectric filter includes a dielectric block, a dielectric layer, and a metal layer. In the dielectric filter, a dielectric constant of the dielectric layer is less than a dielectric constant of the dielectric block, at least one surface of the dielectric block is covered by the dielectric layer, and a surface of the dielectric layer and a surface of the dielectric block that is not covered by the dielectric layer are covered by the metal layer.

Description

[0001] This application claims priority to Chinese Patent Application No. CN202111234366.1, filed on October 22, 2021 and entitled "DIELECTRIC FILTER AND COMMUNICATION DEVICE", which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] Embodiments of this application relate to the field of communication technologies, and specifically, to a dielectric filter and a communication device.

BACKGROUND

[0003] With increasing development of wireless communication technologies, communication devices (for example, base stations) in a wireless communication architecture are increasingly densely distributed, and volumes of the communication devices are required to be increasingly small. In a 5th generation communication technology (5th generation mobile networks, 5G) multiple-input multiple-output (multiple-input multiple-output, MIMO) scenario, a quantity of filters increases accordingly due to a sharp increase in a quantity of transmission channels. Therefore, a requirement on volumes of the filters is high. Due to a high dielectric constant of a dielectric material, for a dielectric filter in a communication device, a size of the filter can be miniaturized, which has advantages of easy production and low costs. Therefore, the dielectric filter has been widely used in 5G base station products. However, in comparison with a previous metal cavity filter, a volume of the dielectric filter is greatly reduced. According to a basic electromagnetic theory, as the volume decreases, loss increases accordingly. Therefore, a requirement for reducing the loss of the dielectric filter is particularly urgent.

[0004] In an existing technical solution of a dielectric filter, metallization is performed directly on a surface of a dielectric block to form a metal layer. When an electromagnetic wave in the dielectric block reaches the metal layer, total internal reflection occurs, and a current is generated on a surface of the metal layer. However, the metal layer is a non-ideal conductor, and the current generated on the surface of the metal layer causes loss, resulting in great loss of the dielectric filter.

[0005] Therefore, how to reduce the loss of the dielectric filter becomes an urgent problem to be resolved.

SUMMARY

[0006] Embodiments of this application provide a dielectric filter and a communication device, to effectively reduce loss of the dielectric filter.

[0007] According to a first aspect, an embodiment of this application provides a dielectric filter. The dielectric filter includes a dielectric block, a dielectric layer, and a metal layer. In the dielectric filter, a dielectric constant of the dielectric layer is less than a dielectric constant of the dielectric block. In addition, at least one surface of the dielectric block is covered by the dielectric layer, and a surface of the dielectric layer and a surface of the dielectric block that is not covered by the dielectric layer are covered by the metal layer. It should be noted that a material of the described dielectric block may be a dielectric material such as ceramic with a high dielectric constant and low loss. A material of the described metal layer may be a metal material such as silver, copper, aluminum, titanium, tin, or gold. Through the foregoing manner, because the dielectric constant of the dielectric block is different from the dielectric constant and wave impedance that are of the dielectric layer, when an electromagnetic wave propagated from the dielectric block reaches the dielectric layer, a part of the electromagnetic wave is reflected, so that energy can be gradually reflected back. In this way, less energy finally reaches the metal layer, so that less loss is caused by a current generated on a surface of the metal layer, thereby effectively reducing loss of the dielectric filter.

[0008] In some possible implementations, the dielectric layer includes N layers, K dielectric layers of the N dielectric layers cover a first surface of the dielectric block, P dielectric layers of the N dielectric layers cover a second surface of the dielectric block, the first surface is different from the second surface, the first surface and the second surface are one or more of the at least one surface, N is a positive integer, K≤N, and P≤N. In this example, the dielectric block may have one or more surfaces, and the first surface may be covered by the K dielectric layers. The K dielectric layers may be stacked for the covering. Similarly, the second surface may be covered by the P dielectric layers. The P dielectric layers may also be stacked for the covering. By stacking a same quantity or different quantities of dielectric layers on different surfaces of the dielectric block, the loss of the dielectric filter can be reduced to different degrees.

[0009] In some possible implementations, dielectric constants of the N dielectric layers are the same; or dielectric constants of the N dielectric layers may be different.

[0010] In some possible implementations, K and P may be the same; or K and P may be different. In other words, a quantity of dielectric layers covering the first surface of the dielectric block and a quantity of dielectric layers covering the second surface of the dielectric block may be the same or may be different.

[0011] In some possible implementations, a material of the dielectric block includes ceramic.

[0012] In some possible implementations, a material of the dielectric filter includes silicon oxide, boron oxide, calcium oxide, and/or aluminum oxide.

[0013] In some possible implementations, a surface of the dielectric block includes at least one hole and/or at least one groove.

[0014] In some possible implementations, a surface of the dielectric block does not include a hole and/or a groove.

[0015] According to a second aspect, an embodiment of this application provides a communication device. The communication device includes the dielectric filter according to any one of the first aspect or the possible implementations of the first aspect. The described dielectric filter may be used in a transceiver channel in a communication system, and connected to a radio frequency front-end filter circuit of the transceiver channel in the communication system, to implement frequency selection of a transceiver signal. It should be noted that the described communication device may be a device such as a base station, a satellite communication device, or a terminal that can be configured for 4G communication or 5G communication, or may be a device such as a base station, a satellite communication device, or a terminal that can be configured for 6G communication in the future. This is not limited in this application.

[0016] According to the foregoing technical solutions, it can be learned that embodiments of this application have the following advantages:

[0017] In embodiments of this application, because the dielectric constant of the dielectric block is greater than the dielectric constant of the dielectric layer, the dielectric constant of the dielectric block is different from the dielectric constant and the wave impedance that are of the dielectric layer. In this case, the dielectric layer is attached to the surface of the dielectric block, and the metal layer is attached to the surface of the dielectric layer. Therefore, when the electromagnetic wave propagated from the dielectric block reaches the dielectric layer, a part of the electromagnetic wave is reflected, so that energy can be gradually reflected back. In this way, less energy finally reaches the metal layer, so that less loss is caused by the current generated on a surface of the metal layer, thereby effectively reducing the loss of the dielectric filter.

BRIEF DESCRIPTION OF DRAWINGS

[0018] To describe the technical solutions in embodiments of this application more clearly, the following briefly describes the accompanying drawings for describing embodiments. It is clear that the accompanying drawings in the following description show merely some embodiments of this application.

FIG. 1 is a schematic diagram of a structure of a dielectric filter in an existing solution;

FIG. 2A is a schematic diagram of a cross section of a dielectric filter according to an embodiment of this application;

FIG. 2B is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application;

FIG. 3A is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application;

FIG. 3B is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application;

FIG. 4A is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application;

FIG. 4B is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application;

FIG. 5A is a schematic diagram of a form of a dielectric filter according to an embodiment of this application;

FIG. 5B is a schematic diagram of another form of a dielectric filter according to an embodiment of this application;

FIG. 5C is a schematic diagram of another form of a dielectric filter according to an embodiment of this application; and

FIG. 6 is a schematic diagram of a communication device according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

[0019] Embodiments of this application provide a dielectric filter and a communication device, to effectively reduce loss of the dielectric filter.

[0020] The following clearly and completely describes the technical solutions in embodiments of this application with reference to the accompanying drawings in embodiments of this application. It is clear that the described embodiments are some but not all of embodiments of this application. All other embodiments obtained by a person of ordinary skill in the art based on embodiments of this application without creative efforts shall fall within the protection scope of this application.

[0021] In the specification, claims, and accompanying drawings of this application, the terms "first", "second", "third", "fourth", and the like (if existent) are intended to distinguish between similar objects but do not necessarily indicate a specific order or sequence. It should be understood that the data termed in such a way are interchangeable in proper circumstances, so that embodiments of this application described herein can be implemented in another order than the order illustrated or described herein. In addition, the terms "include", "have", and any variation thereof are intended to cover a non-exclusive inclusion. In this application, "at least one" means one or more, and "a plurality of" means two or more. The term "and/or" describes an association relationship between associated objects, and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists, where A and B may be singular or plural. The character "/" generally indicates an "or" relationship between the associated objects. "At least one of the following items (pieces)" or a similar expression thereof indicates any combination of these items, including a single item (piece) or any combination of a plurality of items (pieces). For example, at least one of a, b, or c may represent: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural. It should be noted that "at least one item (piece)" may also be explained as "one item (piece) or more items (pieces)".

[0022] Due to advantages such as a high dielectric constant, a small volume, easy production, and low costs, a dielectric filter in a communication device has been widely used in a 5G communication technology. However, in comparison with a previous metal cavity filter, the volume of the dielectric filter is greatly reduced. According to a basic electromagnetic theory, as the volume decreases, loss increases accordingly. Therefore, a requirement for reducing the loss of the dielectric filter is particularly urgent.

[0023] FIG. 1 is a schematic diagram of a structure of a dielectric filter in an existing solution. As shown in FIG. 1, metallization is performed directly on a surface of a dielectric block 101 to form a metal layer 102. In this way, when an electromagnetic wave in the dielectric block 101 reaches the metal layer 102, total internal reflection occurs, and a current is generated on a surface of the metal layer 102. However, the metal layer 102 is a non-ideal conductor, and the current generated on the surface of the metal layer 102 causes loss, resulting in great loss of the dielectric filter 10.

[0024] Based on this, to resolve the foregoing problem of the great loss of the dielectric filter 10, this application provides a dielectric filter. The described dielectric filter 10 may be used in a communication device. The communication device may be used in a communication system for 4G communication, 5G communication, or a future sixth generation mobile communication technology (6th generation mobile networks, 6G). The described dielectric filter 10 may include but is not limited to a ceramic dielectric filter or the like. During actual application, the dielectric filter 10 may alternatively be another filter that can perform frequency selection on a receive/transmit signal of an antenna. This is not specifically limited in this application.

[0025] FIG. 2A is a schematic diagram of a cross section of a dielectric filter according to an embodiment of this application.

[0026] As shown in FIG. 2A, the dielectric filter 10 includes a dielectric block 101, a dielectric layer 103, and a metal layer 102. A dielectric constant of the dielectric layer 103 is less than a dielectric constant of the dielectric block 101. At least one surface of the dielectric block 101 is covered by the dielectric layer 103, and a surface of the dielectric layer 103 and a surface of the dielectric block 101 not covered by the dielectric layer 103 are covered by the metal layer 102.

[0027] In this example, that at least one surface of the dielectric block 101 is covered by the dielectric layer 103 may be understood as that the dielectric layer 103 covers the at least one surface of the dielectric block 101, or may not cover one or more surfaces of the dielectric block 101. In other words, the dielectric layer 103 at least needs to cover one surface of the dielectric block 101. For example, if a shape of the dielectric block 101 is similar to a shape of a cuboid, which has six surfaces, the dielectric layer 103 may cover only one surface of the dielectric block 101, may cover only two surfaces or three surfaces of the dielectric block 101, or the like; alternatively, the dielectric layer 103 may fully cover the surfaces of the dielectric block 101, that is, cover the six surfaces of the dielectric block 101. A specific quantity of surfaces of the dielectric block 101 covered by the dielectric layer 103 may be determined based on a case. This is not limited in this embodiment of this application.

[0028] It should be noted that FIG. 2A is only a schematic diagram in which two surfaces of the dielectric block are covered by the dielectric layer. During actual application, for a schematic diagram in which all surfaces of the dielectric block are fully covered by the dielectric layer, refer to FIG. 2B for understanding.

[0029] In addition, the metal layer may cover the surface of the dielectric layer 103, and cover the surface of the dielectric block 101 not covered by the dielectric layer 103.

[0030] In this embodiment of this application, because the dielectric constant of the dielectric layer 103 is less than the dielectric constant of the dielectric block 101, in a case in which the dielectric constant of the dielectric block 101 is different from the dielectric constant and wave impedance that are of the dielectric layer 103, when an electromagnetic wave propagated from the dielectric block 101 reaches the dielectric layer 103, a part of the electromagnetic wave is reflected, so that energy can be gradually reflected back. In this way, less energy finally reaches the metal layer 102, so that less loss is caused by a current generated on a surface of the metal layer 102, thereby effectively reducing loss of the dielectric filter.

[0031] FIG. 3A is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application.

[0032] To facilitate understanding of the dielectric filter, based on the dielectric filter shown in FIG. 2A, as shown in FIG. 3A, the dielectric layer includes N layers, K dielectric layers of the N dielectric layers cover a first surface of the dielectric block, P dielectric layers of the N dielectric layers cover a second surface of the dielectric block, the first surface is different from the second surface, the first surface and the second surface are one or more of the at least one surface of the dielectric block, N is a positive integer, K≤N, and P≤N.

[0033] In this example, the described first surface may be one or more of the at least one surface of the dielectric block. For example, when a shape of the dielectric block 101 is similar to a shape of a cuboid, which has six surfaces, the first surface may be an upper surface, may include two surfaces: an upper surface and a left side surface, or the like. This is not specifically limited in this application. Similarly, the described second surface may be one or more of the at least one surface of the dielectric block. For example, the second surface may be a lower surface of the dielectric block, may include two surfaces: a lower surface and a front view surface, or the like. This is not specifically limited in this application.

[0034] That K dielectric layers of the N dielectric layers 103 cover a first surface of the dielectric block 101 may be understood as that a first dielectric layer 103K1 of the K dielectric layers 103 covers an outer side of the first surface of the dielectric block 101, a second dielectric layer 103K2 covers an outer surface of the first dielectric layer 103K1, a third dielectric layer covers an outer surface of the second dielectric layer 103K2, and the rest may be deduced by analogy, until a K^th dielectric layer 103KK covers an outer surface of a (K-1)^th dielectric layer. In addition, an outer surface of the K^th dielectric layer 103KK can be covered by the metal layer 102. In addition, dielectric constants of the K dielectric layers 103 are all less than a dielectric constant of the dielectric block 101.

[0035] Similarly, that P dielectric layers of the N dielectric layers 103 cover a second surface of the dielectric block 101 may be understood as that a first dielectric layer 103P1 of the P dielectric layers 103 covers an outer side of the second surface of the dielectric block 101, a second dielectric layer 103P2 covers an outer surface of the first dielectric layer 103P1, a third dielectric layer covers an outer surface of the second dielectric layer 103P2, and the rest may be deduced by analogy, until a P^th dielectric layer 103PP covers an outer surface of a (P-1)^th dielectric layer. In addition, an outer surface of the P^th dielectric layer 103PP can be covered by the metal layer 102. In addition, dielectric constants of the P dielectric layers 103 are all less than the dielectric constant of the dielectric block 101.

[0036] It should be understood that FIG. 3A is only a schematic diagram in which the first surface (for example, a left side surface) of the dielectric block is covered by the K dielectric layers, and the second surface (for example, a right side surface) of the dielectric block is covered by the P dielectric layers. During actual application, for a schematic diagram in which all surfaces of the dielectric block are fully covered by the dielectric layer, refer to FIG. 3B for understanding.

[0037] It should be noted that K and P described above may be the same or may be different. This is not specifically limited in this embodiment of this application. In this embodiment of this application, only an example in which K and P are different is used for description.

[0038] When an electromagnetic wave in the dielectric block 101 is propagated from the first surface of the dielectric block 101 to a junction with the first dielectric layer 103K1, because the dielectric constant of the dielectric block 101 is different from a dielectric constant and wave impedance that are of the first dielectric layer 103K1, a part of the electromagnetic wave is reflected at the junction between the dielectric block 101 and the first dielectric layer 103K1, so that a part of energy is reflected back. In addition, another part of the electromagnetic wave is propagated to the first dielectric layer 103K1, so that energy of the another part can pass through the first dielectric layer 103K1 and be propagated to a junction between the first dielectric layer 103K1 and the second dielectric layer 103K2. After that, a part of the energy is reflected back. Furthermore, a remaining part of the energy passes through the second dielectric layer 103K2, and reaches a junction between the second dielectric layer 103K2 and the third dielectric layer. By analogy, after the energy passes through the (K-1)^th dielectric layer and reaches a junction between the (K-1)^th dielectric layer and the K^th dielectric layer 103KK, a part of the energy is still reflected back. Furthermore, after a remaining part of the energy passes through the K^th dielectric layer 103KK and reaches the metal layer 102, total internal reflection occurs in the metal layer 102. Similarly, an electromagnetic wave may also be propagated in the second surface of the dielectric block 101 in a manner similar to that of propagation in the first surface. After energy passes through the (P-1)^th dielectric layer and reaches a junction between the (P-1)^th dielectric layer and the P^th dielectric layer 103PP, a part of the energy is also reflected back. Furthermore, after a remaining part of the energy passes through the P^th dielectric layer 103PP and reaches the metal layer 102, total internal reflection occurs in the metal layer 102. In this case, when an electromagnetic wave propagated from the dielectric block 101 reaches the dielectric layers 103 in sequence, a part of the electromagnetic wave is reflected, so that energy can be gradually reflected back. In this way, in comparison with the conventional solution described in FIG. 1, less energy finally reaches the metal layer 102, so that less loss is caused by a current generated on a surface of the metal layer 102, thereby effectively reducing loss of the dielectric filter 10.

[0039] It should be noted that, that an outer surface of the K^th dielectric layer 103KK can be covered by the metal layer 102 may also be understood as that the metal layer 102 is attached to the outer surface of the K^th dielectric layer 103KK through electroplating, printing, welding, spraying, or the like. Similarly, that an outer surface of the P^th dielectric layer 103PP can be covered by the metal layer 102 may also be understood as that the metal layer 102 is attached to the outer surface of the P^th dielectric layer 103PP through electroplating, printing, welding, spraying, or the like. The metal layer 102 can limit an electromagnetic wave within the dielectric block 101, to prevent electromagnetic signal leakage. A material of the described metal layer 102 may include but is not limited to a metal material such as silver, copper, aluminum, titanium, tin, or gold.

[0040] In some other examples, dielectric constants of the N dielectric layers 103 may be the same or may be different. This is not limited herein. In other words, values of the dielectric constants of the N dielectric layers 103 are not limited. For example, in a case in which the K dielectric layers 103 cover the first surface of the dielectric block 101, the dielectric constant of the first dielectric layer 103K1 may be greater than a dielectric constant of the second dielectric layer 103K2, or may be less than or equal to the dielectric constant of the second dielectric layer 103K2; alternatively, a dielectric constant of the third dielectric layer may be greater than the dielectric constant of the second dielectric layer 103K2, or the like, which is not limited herein, as long as the dielectric constants of the N dielectric layers 103 are all less than the dielectric constant of the dielectric block 101. For a case in which the P dielectric layers 103 cover the second surface of the dielectric block 101, refer to the foregoing case in which the K dielectric layers 103 cover the first surface of the dielectric block 101 for understanding. Details are not described herein again.

[0041] For example, FIG. 4A is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application. As shown in FIG. 4A, when N=1 and K=P=1, the dielectric filter 10 may include a dielectric block 101, a dielectric layer 103, and a metal layer 102. A dielectric constant of the dielectric layer 103 is less than a dielectric constant of the dielectric block 101. In addition, the dielectric layer 103 is attached to an outer surface of the dielectric block 101, and the metal layer 102 is attached to an outer surface of the dielectric layer 103. When an electromagnetic wave in the dielectric block 101 is propagated from the dielectric block 101 to a junction with the dielectric layer 103, because the dielectric constant of the dielectric block 101 is different from the dielectric constant and wave impedance that are of the dielectric layer 103, a part of the electromagnetic wave is reflected at the junction between the dielectric block 101 and the dielectric layer 103, so that a part of energy is reflected back. In addition, another part of the electromagnetic wave is propagated to the dielectric layer 103, and energy of the another part can pass through the dielectric layer 103 and be propagated to the metal layer 102, so that total internal reflection occurs in the metal layer 102. In this case, when the electromagnetic wave propagated from the dielectric block 101 reaches the dielectric layer 103, the electromagnetic wave is reflected, so that a part of energy can be gradually reflected back. In this way, in comparison with the conventional solution described in FIG. 1, less energy finally reaches the metal layer 102, so that less loss is caused by a current generated on a surface of the metal layer 102, thereby effectively reducing loss of the dielectric filter 10.

[0042] Alternatively, refer to FIG. 4B. FIG. 4B is a schematic diagram of another cross section of a dielectric filter according to an embodiment of this application. As shown in FIG. 4B, when N=2, K=1, and P=2, the dielectric filter 10 may include a dielectric block 101, two dielectric layers 103, and a metal layer 102.

[0043] On a first surface of the dielectric block 101, the dielectric layer 103 may include a first dielectric layer 103K1, and the first dielectric layer 103K1 is attached to an outer side of the first surface of the dielectric block 101. On a second surface of the dielectric block 101, the dielectric layer 103 may include a first dielectric layer 103P1 and a second dielectric layer 103P2, the first dielectric layer 103P1 is attached to an outer side of the second surface of the dielectric block 101, and the second dielectric layer 103P2 is attached to an outer surface of the first dielectric layer 103P1. Further, the metal layer 102 is attached to an outer surface of the first dielectric layer 103K1 and an outer surface of the second dielectric layer 103P2.

[0044] It should be noted that a dielectric constant of the first dielectric layer 103K1, a dielectric constant of the first dielectric layer 103P1, and a dielectric constant of the second dielectric layer 103P2 are all less than a dielectric constant of the dielectric block 101.

[0045] When an electromagnetic wave in the dielectric block 101 is propagated from the first surface of the dielectric block 101 to a junction with the first dielectric layer 103K1, because the dielectric constant of the dielectric block 101 is different from the dielectric constant and wave impedance that are of the first dielectric layer 103K1, a part of the electromagnetic wave is reflected at the junction between the dielectric block 101 and the first dielectric layer 103K1, so that a part of energy is reflected back. In addition, another part reaches the metal layer 102 after passing through the first dielectric layer 103K1, so that total internal reflection occurs in the metal layer 102. Similarly, when an electromagnetic wave is propagated from the second surface of the dielectric block 101 to a junction with the first dielectric layer 103P1, because the dielectric constant of the dielectric block 101 is different from the dielectric constant and wave impedance that are of the first dielectric layer 103P1, a part of the electromagnetic wave is reflected at the junction between the dielectric block 101 and the first dielectric layer 103P1, so that a part of energy is reflected back. In addition, another part of the electromagnetic wave can pass through the first dielectric layer 103P1 and be propagated to a junction between the first dielectric layer 103P1 and the second dielectric layer 103P2. After that, a part of energy is reflected back. Furthermore, a remaining part of the energy passes through the second dielectric layer 103P2 and reaches the metal layer 102, so that total internal reflection occurs in the metal layer 102. In this case, when the electromagnetic wave propagated from the dielectric block 101 reaches the dielectric layers 103 in sequence, the electromagnetic wave is reflected, so that energy can be gradually reflected back. In this way, in comparison with the conventional solution described in FIG. 1, less energy finally reaches the metal layer 102, so that less loss is caused by a current generated on a surface of the metal layer 102, thereby effectively reducing loss of the dielectric filter 10.

[0046] Similarly, during actual application, three dielectric layers 103, four dielectric layers 103, or the like may alternatively be stacked to cover the surface of the dielectric block 101. This is not specifically limited in this embodiment of this application.

[0047] It should be noted that, in the dielectric filters 10 shown in FIG. 2A to FIG. 4B, a structure of the dielectric filter 10 is described only from a cross-sectional perspective. Refer to FIG. 5A. FIG. 5A is a schematic diagram of a form of a dielectric filter 10 according to an embodiment of this application. It can be seen from FIG. 5A that, based on any one of the dielectric filters 10 described in FIG. 2A to FIG. 4B, a surface of a dielectric block 101 may include at least one hole and/or at least one groove. The at least one hole or the at least one groove may be symmetrically distributed based on the dielectric block 101.

[0048] In some other examples, the surface of the dielectric block 101 may alternatively be a flat plane, that is, does not include the hole and/or the groove shown in FIG. 5A. For details, refer to a schematic diagram of another form of the dielectric filter 10 shown in FIG. 5B to FIG. 5C for understanding. It can be seen from FIG. 5B that there is neither a hole nor a groove on the surface of the dielectric block 101. Furthermore, it can be seen from FIG. 5C that there is no hole on the surface of the dielectric block 101.

[0049] In addition, in FIG. 5A to FIG. 5C, only an example in which the dielectric block 101 is a cuboid is used for description. During actual application, the dielectric block 101 may alternatively be in a three-dimensional shape such as a cube, a cylinder, or an elliptical cylinder, which facilitates processing and combination. Certainly, during actual application, the dielectric block 101 may alternatively be in another shape, for example, a cylindrical shape or a trapezoidal shape. A specific shape is not limited in this application. A shape of the described hole may include but is not limited to a circle, a square, a rhombus, or the like. A shape of the described groove may also include but is not limited to a cross shaped groove, a straight elongated groove, a rectangular groove, or the like. This is not limited herein. In addition, a quantity of holes or grooves is not limited in this embodiment of this application.

[0050] It should be noted that a material of the foregoing dielectric block 101 described above may be a dielectric material such as ceramic with a high dielectric constant and low loss. This is not described herein.

[0051] In addition, a material of the described dielectric filter 10 may include a material such as silicon oxide, boron oxide, calcium oxide, and/or aluminum oxide. During actual application, the material of the dielectric filter 10 may alternatively be another material that has a low dielectric constant, low loss, and a temperature coefficient approaching zero, and that can provide a better dielectric property for the dielectric filter 10.

[0052] FIG. 6 is a schematic diagram of a communication device according to an embodiment of this application. As shown in FIG. 6, the communication device may include a dielectric filter 10. The dielectric filter 10 may be coupled to an antenna, and is configured to perform frequency selection on a receive/transmit signal of the antenna. It should be noted that the dielectric filter 10 in FIG. 6 may be understood with reference to the dielectric filter 10 described in FIG. 2A to FIG. 5C. A structure and an operating principle that are of the dielectric filter 10 are not described herein again.

[0053] The described communication device may include but is not limited to a device such as a base station or a terminal that can be configured for 5G communication, or may be a device such as a base station, a satellite communication device, or a terminal that can be configured for 6G communication in the future. The described terminal may further include but is not limited to at least one of a foldable electronic device, a tablet computer, a desktop computer, a laptop computer, a handheld computer, a notebook computer, an ultra-mobile personal computer (ultra-mobile personal computer, UMPC), a netbook, a cellular phone, a personal digital assistant (personal digital assistant, PDA), an augmented reality (augmented reality, AR) device, a virtual reality (virtual reality, VR) device, an artificial intelligence (artificial intelligence, AI) device, a wearable device, a vehicle-mounted device, a smart home device, or a smart city device. This is not specifically limited.

[0054] It may be clearly understood by a person skilled in the art that, for the purpose of convenient and brief description, for a detailed working process of the foregoing system, apparatus, and unit, refer to a corresponding process in the foregoing method embodiments, and details are not described herein again.

[0055] The foregoing embodiments are merely intended to describe the technical solutions of this application, but not intended to limit this application. Although this application is described in detail with reference to the foregoing embodiments, a person of ordinary skill in the art should understand that modifications may still be made to the technical solutions described in the foregoing embodiments or equivalent replacements may be made to some technical features thereof, and such modifications or replacements do not cause the essence of the corresponding technical solutions to depart from the and scope of the technical solutions of embodiments of this application.

Claims

1. A dielectric filter, wherein the dielectric filter comprises a dielectric block, a dielectric layer, and a metal layer; and a dielectric constant of the dielectric layer is less than a dielectric constant of the dielectric block; and
at least one surface of the dielectric block is covered by the dielectric layer, and a surface of the dielectric layer and a surface of the dielectric block that is not covered by the dielectric layer are covered by the metal layer.

2. The dielectric filter according to claim 1, wherein the dielectric layer comprises N layers, K dielectric layers of the N dielectric layers cover a first surface of the dielectric block, P dielectric layers of the N dielectric layers cover a second surface of the dielectric block, the first surface is different from the second surface, the first surface and the second surface are one or more of the at least one surface of the dielectric block, N is a positive integer, K≤N, and P≤N.

3. The dielectric filter according to claim 2, wherein dielectric constants of the N dielectric layers are the same.

4. The dielectric filter according to claim 2, wherein dielectric constants of the N dielectric layers are different.

5. The dielectric filter according to any one of claims 2 to 4, wherein K and P are the same; or K and P are different.

6. The dielectric filter according to any one of claims 1 to 5, wherein a material of the dielectric block is ceramic.

7. The dielectric filter according to any one of claims 1 to 6, wherein a material of the dielectric filter comprises silicon oxide, boron oxide, calcium oxide, and/or aluminum oxide.

8. The dielectric filter according to any one of claims 1 to 7, wherein a surface of the dielectric block comprises at least one hole and/or at least one groove.

9. The dielectric filter according to any one of claims 1 to 7, wherein a surface of the dielectric block does not comprise a hole and/or a groove.

10. A communication device, wherein the communication device comprises the dielectric filter according to any one of claims 1 to 9.

Drawing