Dielectric filter, radio frequency processing unit and base station

Abstract

The invention relates to the technical field of communication, discloses a dielectric filter, a radio frequency processing unit and a base station, and aims to improve the port coupling coefficient of the dielectric filter so as to expand the bandwidth of the dielectric filter. The dielectric filter comprises a dielectric main body, a coupling port and one or more resonant cavities, the coupling port and the resonant cavities are arranged on the dielectric main body, the dielectric main body is provided with a first surface, a second surface and a side surface, the first surface is opposite to the second surface, and the coupling port extends from the side surface to the interior of the dielectric main body; the coupling port comprises a blind hole formed in the first surface, a first open slot formed in the second surface and a second open slot formed in the side surface, the first open slot extends in the direction of the side surface and is communicated with the second open slot, and the projection of the outer contour of the first open slot on the first surface covers at least part of the blind hole; the blind hole, the first slot and the second slot are respectively provided with a metalized inner wall, and the blind hole can be coupled with the first slot.

Description

A dielectric filter, radio frequency processing unit and base station Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a dielectric filter, a radio frequency processing unit, and a base station. Background Art

[0002] With the development of modern wireless communication technology, communication systems are becoming increasingly miniaturized, integrated, and multifunctional. Consequently, the requirements for RF links are becoming increasingly stringent. Filters are a crucial component in RF front-end links. Currently, dielectric filters are widely used in communication systems due to their small size, low insertion loss, and excellent stability. However, current dielectric filters generally suffer from weak coupling between the connection port and the resonant cavity, resulting in a certain amount of transmission delay, which in turn hinders further improvement of the filter bandwidth.

[0003] Summary of the Invention

[0004] The present application provides a dielectric filter, a radio frequency processing unit, and a base station to improve the port coupling coefficient of the dielectric filter, thereby expanding the bandwidth of the dielectric filter.

[0005] In a first aspect, the present application provides a dielectric filter, which may include a dielectric body, a coupling port disposed on the dielectric body, and one or more resonant cavities. The dielectric body may include a first surface, a second surface, and a side surface, wherein the first surface and the second surface are positioned opposite each other. The coupling port may extend from the side surface of the dielectric body toward the interior of the dielectric body. The coupling port may include a blind hole, a first slot, and a second slot. The blind hole may be disposed on the first surface of the dielectric body, the first slot may be disposed on the second surface of the dielectric body, and the second slot may be disposed on the side surface of the dielectric body. The first slot may extend toward the side surface of the dielectric body and penetrate the second slot, and the projection of the outer contour of the first slot on the first surface of the dielectric body may cover at least a portion of the blind hole. The blind hole, the first slot, and the second slot each have a metallized inner wall, and the blind hole is coupled to the first slot.

[0006] In the above scheme, by providing a second slot on the side of the dielectric body that penetrates the first slot, the entire slot-shaped structure formed by the first and second slots can serve as a resonant cavity of the dielectric filter, and the two slots have opposite effects on the resonant frequency of the dielectric cavity. At the same time, the depth of the first slot affects the coupling strength between it and the blind hole. Based on this principle, by reasonably designing the depths of the first and second slots, the port coupling strength of the dielectric filter can be improved, the delay can be reduced, and the bandwidth of the dielectric filter can be expanded while maintaining the original resonant frequency.

[0007] Illustratively, the inner wall of the blind hole, the first slot or the second slot may be formed into a metallized inner wall by an electroplating process, and the material of the metal includes but is not limited to silver, gold or tin.

[0008] In some possible implementations, the alignment direction of the first and second surfaces of the dielectric body is defined as a first direction. Along this first direction, the depths of the first and second slots differ. A deeper first slot has a lower resonant frequency of the resonant cavity, while a shallower slot has a higher resonant frequency. A deeper second slot has a higher resonant frequency of the resonant cavity, while a shallower slot has a lower resonant frequency. In this way, by adjusting the depths of the first and second slots, the resonant frequency of the resonant cavity can be tailored to meet the specific performance requirements of the dielectric filter.

[0009] For example, along the first direction, the depth of the second slot can be greater than the depth of the first slot. When the port coupling strength of the dielectric filter is increased by deepening the depth of the first slot, the resonant frequency of the resonant cavity is reduced. To maintain the original resonant frequency, the depth of the second slot can be further deepened, so that the depth of the second slot is greater than the depth of the first slot. In this way, the frequency reduction caused by the first slot can be offset by the frequency increase caused by the second slot, thereby achieving the effects of enhancing the port coupling strength and reducing the time delay while maintaining the original resonant frequency.

[0010] In some possible implementations, the projection of the outer contour of the second slot on the first surface may be spaced apart from the blind hole to reduce the risk of interference with the blind hole when the second slot is deep, thereby improving the structural reliability of the dielectric filter.

[0011] In some possible embodiments, the first slot may include a semicircular slot and a rectangular slot. The semicircular slot is located on a side of the rectangular slot away from the side of the dielectric body, and the opening of the semicircular slot is arranged toward the rectangular slot, thereby achieving communication with the rectangular slot at the opening. This design can improve the quality factor of the dielectric filter and help enhance the filtering performance of the dielectric filter.

[0012] In some possible implementations, the dielectric body may be a rectangular parallelepiped. In this case, in addition to the first surface and the second surface, the dielectric body further includes four side surfaces arranged in pairs. The second slot of the coupling port may be arranged on one of the side surfaces of the dielectric body.

[0013] In some other possible implementations, the dielectric body may be a cylinder. In this case, the second slot of the coupling port is provided on the peripheral surface of the dielectric body.

[0014] In some possible embodiments, the dielectric body may be made of ceramic. For example, the main components of the dielectric body include, but are not limited to, high dielectric constant ceramics such as barium titanate and barium carbonate.

[0015] In the second aspect, the present application also provides a radio frequency processing unit, which may include a power amplifier and a dielectric filter in any possible implementation scheme of the first aspect mentioned above, and the coupling port of the dielectric filter is connected to the power amplifier to filter the signal in the transmitting direction and transmit it into the power amplifier for amplification, or to filter the signal amplified by the power amplifier in the receiving direction.

[0016] In some possible implementation schemes, the blind hole of the coupling port may be electrically connected to the power amplifier via a coaxial line.

[0017] In a third aspect, the present application further provides a base station, which may include an antenna, a baseband processing unit, and the radio frequency processing unit described in the second aspect, wherein the radio frequency processing unit is connected between the baseband processing unit and the antenna. Because the dielectric filter in the radio frequency processing unit can achieve broadband filtering, the communication capability of the base station can also be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic diagram of a system architecture provided by an embodiment of the present application;

[0019] FIG2 is a schematic structural diagram of a base station provided in an embodiment of the present application;

[0020] FIG3 is a schematic diagram of the structure of an active antenna unit provided in an embodiment of the present application;

[0021] FIG4 is a schematic structural diagram of a dielectric filter provided in an embodiment of the present application;

[0022] FIG5 is a schematic diagram of a partial structure of the dielectric filter shown in FIG4 ;

[0023] FIG6 is a schematic diagram of a cross-sectional structure of the dielectric filter shown in FIG5 at a side perspective;

[0024] FIG7 a is a simulation result of the port delay of a traditional dielectric filter;

[0025] FIG7 b is a simulation result of the port delay of the dielectric filter provided in an embodiment of the present application.

[0026] Reference numerals:

[0027] 1-active antenna unit; 11-radome; 12-antenna; 121-reflector; 122-antenna unit; 13-RF processing unit;

[0028] 131 - frequency converter; 132 - filter; 1321 - dielectric body; 13211 - first surface of dielectric body;

[0029] 13212 - second side of dielectric body; 13213 - side of dielectric body; 1322 - coupling port; 13221 - blind hole;

[0030] 13222-first slot; 132221-semicircular slot; 132222-rectangular slot; 13223-second slot;

[0031] 133 - power amplifier; 1323 - resonant cavity; 1324 - coupling window; 2 - pole; 3 - antenna adjustment bracket;

[0032] 4-Baseband processing unit. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0034] Figure 1 exemplarily shows a schematic diagram of a system architecture applicable to an embodiment of the present application. As shown in Figure 1, the system architecture includes a wireless access network communication device and a terminal, and wireless communication can be carried out between the communication device and the terminal. The embodiment shown in Figure 1 is explained by taking the communication device as a base station as an example. The base station can be located in a base station subsystem (BSS), a terrestrial radio access network (UMTS terrestrial radio access network, UTRAN) or an evolved universal terrestrial radio access (E-UTRAN), and is used to provide cell coverage of wireless signals to achieve connection between the terminal device and the wireless network radio frequency end. Specifically, the base station can be a base station (base transceiver station, BTS) in a GSM or CDMA system, a base station (NodeB, NB) in a WCDMA system, an evolutionary base station (eNB or eNodeB) in a long term evolution (LTE) system, or a wireless controller in a cloud radio access network (CRAN) scenario, or the base station can also be a relay station, an access point, a vehicle-mounted device, a wearable device, a base station in a 5G network, or a base station in a future evolved public land mobile network (PLMN), etc., for example, a new wireless base station, which is not limited in the embodiments of the present application.

[0035] Figure 2 shows a schematic diagram of the structure of a base station according to an embodiment of the present application. The base station includes an active antenna unit (AAU) 1, a mast 2, an antenna adjustment bracket 3, a baseband unit (BBU) 4, and other structures. The AAU 1 may include a radome 11. This radome 11 has excellent electrical electromagnetic wave penetration characteristics and mechanical properties that can withstand harsh external environments, thereby protecting the AAU from external environmental influences. The radome 11 can be mounted on a mast 2 or a tower via an antenna adjustment bracket to facilitate the reception or transmission of antenna signals.

[0036] More specifically, reference may be made to FIG. 2 and FIG. 3 , which is a schematic diagram of the composition of an AAU according to a possible embodiment of the present application. The AAU 1 may further include an antenna 12 and a radio frequency processing unit 13, wherein the radio frequency processing unit 13 is connected to the feeding structure of the antenna 12. The radio frequency processing unit 13 may be used to perform frequency selection, amplification, and frequency conversion processing on the signal received by the antenna 12, and convert it into an intermediate frequency signal or a baseband signal and send it to the baseband processing unit 4, or the radio frequency processing unit 13 may be used to convert the intermediate frequency signal of the baseband processing unit 4 into an electromagnetic wave after up-conversion and amplification processing, and then send it out through the antenna 12. The baseband processing unit 4 is connected to the radio frequency processing unit 13 and is used to process the intermediate frequency signal or baseband signal sent by the radio frequency processing unit 13.

[0037] In a specific embodiment, the antenna 12 may include a reflector 121 and multiple antenna units 122. The reflector 121 and antenna units 122 may be disposed within the radome 11. The antenna units 122, which may also be referred to as antenna elements or oscillators, can effectively transmit or receive antenna signals. The reflector 121, which may also be referred to as a base plate, antenna panel, or reflective surface, may be made of metal. When the antenna 12 receives a signal, the reflector 121 can reflect and focus the antenna signal at the receiving point. When the antenna 12 transmits a signal, the signal directed to the reflector 121 is reflected and transmitted. The antenna units 122 are typically placed on one side of the reflector 121. This not only greatly enhances the antenna's signal reception or transmission capabilities, but also blocks and shields interference with antenna signal reception from other radio waves originating from the back side of the reflector 121 (the back side of the reflector 121 in this application refers to the side of the reflector 121 opposite to the side where the antenna units 122 are disposed).

[0038] In a specific embodiment, the RF processing unit 13 may include a frequency converter 131, a filter 132, and a power amplifier 133. In the signal transmission direction, the frequency converter 131 can be used to up-convert the signal of the baseband processing unit 4, and transmit the signal to the filter 132 after frequency conversion. The filter 132 filters the signal and then enters the power amplifier 133 for amplification, and finally converts it into an electromagnetic wave by the antenna 12 and sends it out; in the signal receiving direction, the power amplifier 133 can be used to perform low-noise amplification on the signal received by the antenna 12, and then transmit it to the filter 132 for filtering processing, and then transmit it to the frequency converter 131 by the filter 132 for down-conversion processing and then transmit it to the baseband processing unit 4.

[0039] As a key component of the RF front-end circuit, the performance of the filter directly affects the overall communication capability of the base station. Currently, common filters include metal cavity filters and dielectric filters. Among them, dielectric filters are increasingly widely used in the RF processing units of base stations due to their small size, low insertion loss, and good stability. With the continuous evolution of base stations, there are increasingly higher requirements for the performance of filters, such as requiring filters to have high suppression and broadband filtering characteristics. However, current dielectric filters generally have the problem of weak coupling strength between the connection port and the resonant cavity, resulting in a certain amount of transmission delay, which in turn affects the further improvement of the filter bandwidth.

[0040] To address the above-mentioned issues, embodiments of the present application provide a dielectric filter that can adjust its port coupling coefficient through corresponding structural design, thereby adjusting the bandwidth of the dielectric filter, thereby providing a feasible solution for achieving broadband filtering characteristics for the dielectric filter. This application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Referring to FIG. 4 , FIG. 4 is a schematic diagram of the structure of a dielectric filter provided in an embodiment of the present application. In the following embodiments, dielectric filters and filters are described using the same reference numerals. The dielectric filter 132 includes a dielectric body 1321. The shape of the dielectric body 1321 includes, but is not limited to, a rectangular parallelepiped, a cylindrical, or a block structure of other shapes. FIG. 4 illustrates the dielectric body 1321 as a rectangular parallelepiped. The material of the dielectric body 1321 can be a ceramic dielectric. Exemplarily, the main components of the dielectric body 1321 include, but are not limited to, high dielectric constant ceramics such as barium titanate (BaTiO3), barium carbonate (BaCO3), BaO-Ln2O3-TiO3-2 series microwave dielectric ceramics, or composite perovskite series microwave dielectric ceramics. The high dielectric constant dielectric body 1321 can shorten the wavelength of electromagnetic waves propagating therein, thereby helping to reduce the structural size of the dielectric body 1321. It should be noted that in the embodiment of the present application, a high dielectric constant can be understood as a higher dielectric constant that can be applied to the dielectric filter 132. For example, the dielectric constant can be higher than 6, but the present application does not exclude the case where the dielectric constant is less than or equal to 6, as long as the filtering requirements are met.

[0042] In this embodiment, the dielectric body 1321 may include a first surface 13211 and a second surface 13212. The first surface 13211 and the second surface 13212 may be arranged opposite each other along a first direction. Furthermore, the dielectric body 1321 may further include side surfaces 13213. For example, when the dielectric body 1321 is a rectangular parallelepiped, in addition to the first surface 13211 and the second surface 13212, the dielectric body 1321 may further include four side surfaces 13213, with each pair of side surfaces 13213 being arranged opposite each other. When the dielectric body 1321 is a cylinder, the side surfaces 13213 are the circumferential surfaces of the cylinder.

[0043] The dielectric body 1321 may be provided with a coupling port 1322 and a resonant cavity 1323. The coupling port 1322 may extend from a side surface 13213 of the dielectric body 1321 into the interior of the dielectric body 1321 and may be used to electrically connect to an external device, such as a frequency converter or a power amplifier. For example, there may be two coupling ports 1322, each located near two opposing sides of the dielectric body 1321. The left coupling port 1322 may be used to electrically connect to the frequency converter, while the right coupling port 1322 may be used to electrically connect to the power amplifier. There may be one or more resonant cavities 1323, which may be staggered between the two coupling ports 1322. Adjacent resonant cavities 1323 may be coupled to each other, and resonant cavities 1323 located near a coupling port 1322 may also be coupled to the coupling port 1322. In this manner, signal energy may be transferred between the two coupling ports 1322 and the signal may be filtered. For example, in the signal transmission direction, the signal can be coupled from the left coupling port 1322 through each resonant cavity 1323 to the right coupling port 1322 along the path shown by the solid line in FIG4 . In the signal reception direction, the signal can be coupled from the right coupling port 1322 through each resonant cavity 1323 to the left coupling port 1322 along the path shown by the dotted line in FIG4 . Here, the coupling connection can be understood as a connection method in which there is no direct electrical contact between the coupling port 1322 and the resonant cavity 1323, or between different resonant cavities 1323, but rather interaction enables signal energy transmission between the two, thereby achieving signal transmission.

[0044] Of course, in some other embodiments, the coupling port 1322 on the left can also be connected to the power amplifier, and the coupling port 1322 on the right can be connected to the frequency converter. In this case, in the signal transmission direction, the signal can be coupled from the coupling port 1322 on the right through the various resonant cavities 1323 to the coupling port 1322 on the left along the path shown by the dotted line in Figure 4. In the signal receiving direction, the signal can be coupled from the coupling port 1322 on the left through the various resonant cavities 1323 to the coupling port 1322 on the right along the path shown by the solid line in Figure 4.

[0045] In addition, one or more coupling windows 1324 may be provided on the dielectric body 1321 . These coupling windows 1324 may be used to adjust the coupling coefficient between the resonant cavities 1323 , thereby adjusting the resonant frequency or bandwidth of the dielectric filter 132 and improving the filtering performance of the dielectric filter 132 .

[0046] Referring to FIG. 5 , FIG. 5 is a schematic diagram of a partial structure of the dielectric filter 132 shown in FIG. 4 , specifically the portion including the coupling port. In this embodiment, the coupling port 1322 may include a blind hole 13221 disposed on the first surface 13211. The blind hole 13221 may have a metallized inner wall to facilitate electrical connection to an external device. For example, the blind hole 13221 of the coupling port 1322 may be electrically connected to the external device via a coaxial cable 134. In a specific implementation, the inner conductor at the end of the coaxial cable 134 connecting to the dielectric filter 132 may be welded to the metallized inner wall of the blind hole 13221. This not only achieves electrical connection between the coaxial cable 134 and the blind hole 13221, but also structurally secures the coaxial cable 134 and the dielectric filter 132 relative to each other, thereby improving the reliability of the connection between the two. The blind hole 13221 can form a metal coating on its inner wall through a process such as electroplating, thereby realizing a metallized inner wall. The material of the metallized inner wall of the blind hole 13221 includes but is not limited to silver, gold or tin.

[0047] Continuing with FIG5 , the coupling port 1322 may further include a first slot 13222 and a second slot 13223. The first slot 13222 is disposed on the second side 13212 of the dielectric body 1321, and the second slot 13223 is disposed on the side 13213 of the dielectric body 1321. The first slot 13222 may extend toward the side 13213 of the dielectric body 1321 and pass through the second slot 13223. The projection of the outer contour of the first slot 13222 on the first side 13211 of the dielectric body 1321 may partially cover or completely cover the blind hole 13221 disposed on the first side 13211. The inner walls of the first slot 13222 and the second slot 13223 may also be metallized using an electroplating process. Similarly, the metallized inner walls of the first slot 13222 and the second slot 13223 may be made of, but not limited to, silver, gold, or tin. At this time, the entire slot-shaped structure formed by the first slot 13222 and the second slot 13223 can also serve as a resonant cavity of the dielectric filter 132. The resonant cavity can be coupled and connected with the blind hole 13221, and can also be coupled and connected with other resonant cavities arranged near the coupling port on the dielectric body 1321, thereby transmitting the signal energy received by the blind hole 13221 to other resonant cavities.

[0048] Continuing with reference to FIG5 , in a specific implementation, the first slot 13222 may include a semicircular slot 132221 and a rectangular slot 132222 connected to the semicircular slot 132221. The semicircular slot 132221 may be located on a side of the rectangular slot 132222 away from the side 13213, and the opening of the semicircular slot 132221 is disposed toward the rectangular slot 132222, thereby enabling communication with the rectangular slot 132222 at the opening. This structure can improve the quality factor (q-value) of the dielectric filter 132, thereby helping to enhance the filtering performance of the dielectric filter 132. For example, the width of the rectangular slot 132222 may be equal to the diameter of the semicircular slot 132221. In this case, the cross-sectional shape of the first slot 13222 perpendicular to the first direction is approximately half a racetrack shape. For example, when the dielectric body 1321 is a cuboid, the cross-sectional shape of the second slot 13223 may be a rectangle, and the width of the second slot 13223 is equal to the width of the rectangular slot 132222 .

[0049] In an embodiment of the present application, the depth of the second slot 13223 and the first slot 13222 in the first direction may be the same or different. That is, the bottom wall of the first slot 13222 and the bottom wall of the second slot 13223 may be in the same plane, or there may be a certain height difference, in which case a step may be formed between the two. The depth of the first slot 13222 and the depth of the second slot 13223 both have an impact on the resonant frequency of the resonant cavity, specifically, the deeper the depth of the first slot 13222, the lower the resonant frequency of the resonant cavity, and conversely, the shallower the depth of the first slot 13222, the higher the resonant frequency of the resonant cavity; the deeper the depth of the second slot 13223, the higher the resonant frequency of the resonant cavity, and conversely, the shallower the depth of the second slot 13223, the lower the resonant frequency of the resonant cavity. It can be seen that the depth of the two slots has opposite effects on the resonant frequency of the resonant cavity. Based on this principle, the depth of the first slot 13222 and the depth of the second slot 13223 can be adjusted according to the design parameters of the dielectric filter 132 so that the resonant frequency of the resonant cavity meets the specific performance of the dielectric filter 132.

[0050] In addition to affecting the resonant frequency of the resonant cavity, the depth of the first slot 13222 also affects the coupling strength between the first slot 13222 and the blind hole 13221. The deeper the first slot 13222, the shorter the distance between the bottom wall of the first slot 13222 and the bottom wall of the blind hole 13221. This increases the coupling strength between the first slot 13222 and the blind hole 13221, reduces port delay, and further increases the bandwidth of the dielectric filter 132.

[0051] The above analysis shows that increasing the depth of the first slot 13222 can improve the port coupling strength of the dielectric filter 132 while simultaneously reducing the resonant frequency of the resonant cavity. In some cases, if the dielectric filter 132 needs to maintain its original resonant frequency while also increasing its bandwidth, the resonant frequency can be increased by deepening the depth of the second slot 13223, for example by making the depth of the second slot 13223 greater than the depth of the first slot 13222. In this way, the frequency reduction caused by the first slot 13222 can be offset by the frequency increase caused by the second slot 13223, thereby achieving both enhanced port coupling strength and reduced latency while maintaining the original resonant frequency.

[0052] Referring to Figures 5 and 6 , Figure 6 is a schematic cross-sectional view of the dielectric filter shown in Figure 5 from a side perspective. In some embodiments, the projection of the outer contour of the second slot 13223 on the first surface 13211 may be spaced apart from the blind hole 13221 provided on the first surface 13211. As shown in Figure 6 , the projection of the outer contour of the second slot and the blind hole is spaced apart by a distance h. This reduces the risk of interference between the second slot 13223 and the blind hole when the second slot 13223 is deep, thereby improving the structural reliability of the dielectric filter 132.

[0053] Referring to Figures 7a and 7b, taking the coupling scheme with a resonant cavity resonant frequency of 3.5 GHz as an example, when the hole depth of the blind hole 13221 is the same, the port delays of the traditional dielectric filter and the dielectric filter provided in the embodiment of the present application are simulated respectively. Figure 7a is the simulation result of the traditional dielectric filter, and Figure 7b is the simulation result of the dielectric filter provided in the embodiment of the present application. It can be seen that the delay of the traditional coupling scheme is approximately 7.3 ns, while the delay of the dielectric filter provided in the embodiment of the present application is only about 3.65 ns. Compared with the traditional scheme, the port delay of the dielectric filter in the embodiment of the present application can be reduced by half, which is equivalent to doubling the relative bandwidth of the dielectric filter.

[0054] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A dielectric filter, characterized in that: The device comprises a dielectric body, a coupling port and a resonant cavity provided on the dielectric body, wherein the dielectric body has a first surface, a second surface and a side surface, the first surface and the second surface are opposite to each other, and the coupling port extends from the side surface to the interior of the dielectric body; wherein: The coupling port includes a blind hole provided on the first surface, a first slot provided on the second surface, and a second slot provided on the side surface, wherein the first slot extends toward the side surface and penetrates the second slot, and a projection of an outer contour of the first slot on the first surface covers at least a portion of the blind hole; the blind hole, the first slot, and the second slot respectively have metallized inner walls, and the blind hole is coupled to the first slot.

2. The dielectric filter according to claim 1, wherein Along a first direction, a depth of the first groove is different from a depth of the second groove; The first direction is the arrangement direction of the first surface and the second surface.

3. The dielectric filter according to claim 2, wherein Along the first direction, the depth of the second groove is greater than the depth of the first groove.

4. The dielectric filter according to claim 2 or 3, wherein: A projection of an outer contour of the second slot on the first surface is spaced apart from the blind hole.

5. The dielectric filter according to any one of claims 2 to 4, characterized in that The first slot includes a semicircular slot and a rectangular slot connected to the semicircular slot. The opening of the semicircular slot is arranged toward the rectangular slot, and the semicircular slot is located on a side of the rectangular slot away from the side surface.

6. The dielectric filter according to any one of claims 1 to 5, wherein The medium body is a rectangular parallelepiped, and the second slot is provided on one of the side surfaces of the medium body.

7. The dielectric filter according to any one of claims 1 to 5, wherein: The medium body is a cylinder.

8. The dielectric filter according to any one of claims 1 to 7, wherein: The material of the dielectric body is ceramic.

9. A radio frequency processing unit, characterized in that: The device comprises a power amplifier and the dielectric filter according to any one of claims 1 to 8, wherein a coupling port of the dielectric filter is connected to the power amplifier.

10. A base station, characterized in that: The invention comprises an antenna, a baseband processing unit and the radio frequency processing unit according to claim 9, wherein the radio frequency processing unit is connected between the baseband processing unit and the antenna.

Images