Filter and communication device

Abstract

Provided in the present application are a filter and a communication device. The filter comprises a first dielectric plate, a filter structure and a second dielectric plate that are stacked in a first direction, wherein the filter structure is located between the first dielectric plate and the second dielectric plate; a first signal transmission structure is provided on the first dielectric plate, the first signal transmission structure being configured to input a received first signal into the filter structure; and a second signal transmission structure is provided on the second dielectric plate, the second signal transmission structure being configured to output a signal obtained by filtering the first signal by the filter structure. A signal input port and a signal output port of the filter are vertically integrated in the first direction, such that the filter has a small size and is easy to integrate into an antenna.

Description

Filters and communication devices

[0001] This application claims priority to Chinese Patent Application No. 202510284164.X, filed on March 10, 2025, entitled "Filter and Communication Apparatus", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and in particular to a filter and a communication device. Background Technology

[0003] In the field of wireless communication, information transmission between various wireless devices relies on radio waves. To prevent information interference, multiple devices can be set to different operating frequency bands. Filters, as an important radio frequency device to ensure the performance of wireless communication products, are widely used in communication systems. Filters can filter out noise outside the frequency band required by the current device, thus selecting the useful signal. However, as communication systems develop towards miniaturization and multi-frequency integration, the distance between antenna elements is becoming increasingly compact. At this point, traditional filters face the problems of large size and difficulty in integration. Summary of the Invention

[0004] This application provides a filter and a communication device, which aims to solve the problems of traditional filters being large in size and difficult to integrate.

[0005] In a first aspect, a filter is provided, comprising: a first dielectric substrate, a filter structure, and a second dielectric substrate stacked in a first direction, the filter structure being located between the first dielectric substrate and the second dielectric substrate, a first signal transmission structure being disposed on the first dielectric substrate for inputting a received first signal to the filter structure, and a second signal transmission structure being disposed on the second dielectric substrate for outputting a signal obtained by filtering the first signal by the filter structure.

[0006] In the above technical solution, the first signal transmission structure in the filter can serve as the signal input port of the filter for the input of the first signal, and the second signal transmission structure can serve as the signal output port of the filter for the output of the filtered first signal. Since the first and second signal transmission structures are stacked in the first direction, the signal input and output ports of the filter can be vertically integrated in the first direction, thereby making the filter smaller in size and easier to integrate into an antenna. For example, in the prior art, since microstrip lines usually have a certain length, there is a certain distance between the output port and the input port of the filter, making it difficult to significantly reduce the planar size of the filter. Based on the embodiments provided in this application, both the first and second signal transmission structures are arranged in the first direction (i.e., vertically integrated). In this way, the distance between the input and output ports of the filter is not affected by the length of the microstrip line, thus significantly reducing the overall size of the filter, making the filter extremely small in size, easy to apply in filtered antenna design, and achieving high isolation between antenna elements.

[0007] In some implementations of the first aspect, the filtering structure includes a third dielectric layer, on which a third signal transmission structure and a first stripline are disposed. The first stripline is used to filter the first signal to obtain a second signal, and the third signal transmission structure is used to receive the first signal from the first signal transmission structure and output the second signal.

[0008] The above technical solution provides a specific filtering structure, which can be used to filter signals based on the first stripline in the filtering structure.

[0009] In some implementations of the first aspect, the first stripline includes at least one strip stub, which is connected to the third signal transmission structure.

[0010] It is understood that the connection here can be a direct connection or an indirect connection. For example, a direct connection between a stub and the third signal transmission structure can be that the stub is drawn from the third signal transmission structure. As another example, an indirect connection between a stub and the third signal transmission structure can be that the stub is drawn from other stubs drawn from the third signal transmission structure.

[0011] In some implementations of the first aspect, the first stripline includes multiple strip branches, and at least two striplines in the first stripline have different lengths.

[0012] In the above technical solution, the filtering range of the filter can be adjusted by setting strip-shaped branches of different lengths.

[0013] In some implementations of the first aspect, the first stripline includes multiple strip segments, at least two of which have different impedances and phases.

[0014] In the above technical solution, setting strip stubs with different impedances and phases can extend the filtering bandwidth of the filter and enhance the filtering effect.

[0015] In some implementations of the first aspect, the first strip line includes 3, 4, or 5 strip branches.

[0016] In some implementations of the first aspect, the first signal transmission structure, the second signal transmission structure, and the third signal transmission structure are respectively the first signal hole, the second signal hole, and the third signal hole.

[0017] In some implementations of the first aspect, the first signal hole, the second signal hole, and the third signal hole are connected in the first direction.

[0018] The above technical solution has a simple manufacturing process, which facilitates the transmission of signals between the signal holes based on traditional printed circuit board processing technology.

[0019] In some implementations of the first aspect, the third dielectric layer is a third dielectric substrate.

[0020] In some implementations of the first aspect, a first distance is spaced between the first dielectric substrate and the third dielectric substrate, and a second distance is spaced between the third dielectric substrate and the second dielectric substrate, wherein the first distance and the second distance are not the same.

[0021] In the above technical solution, the filtering range of the first stripline can be adjusted by changing the first distance and / or the second distance.

[0022] In some implementations of the first aspect, the filter further includes: shielding structures respectively disposed on the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate, the shielding structures including multiple shielding holes.

[0023] In the above technical solution, the shielding structure can ensure low-loss transmission of radio frequency signals and can be used to isolate circuit board areas operating at different frequencies.

[0024] In some implementations of the first aspect, the filtering structure further includes a fourth dielectric layer, on which a fourth signal transmission structure and a second stripline are disposed. The second stripline is used to filter the second signal again to obtain a third signal, and the fourth signal transmission structure is used to receive the second signal and output the third signal.

[0025] In the above technical solution, the first and second striplines in the filter can be cascaded for filtering. Specifically, the second signal obtained after filtering based on the first stripline can be transmitted to the second stripline for further filtering through the third and fourth signal transmission structures. This cascading method allows for flexible adjustment of the passband and stopband ranges, expanding the filter's bandwidth and enabling effective suppression of out-of-band signals within a smaller size, thus improving the filtering effect.

[0026] In some implementations of the first aspect, the filtering structure further includes a fifth dielectric substrate, on which a fifth signal transmission structure is disposed. The fifth dielectric substrate is located between the third dielectric layer and the fourth dielectric layer. The fifth signal transmission structure is used to receive the second signal and to transmit the second signal to the fourth signal transmission structure.

[0027] In the above technical solution, a fifth dielectric plate is added between the third dielectric plate with the first stripline and the fourth dielectric plate with the second stripline. This can isolate the first and second striplines, avoid coupling between the striplines, and reduce design complexity.

[0028] In some implementations of the first aspect, the second stripline includes at least one strip stub, which is connected to the fourth signal transmission structure.

[0029] In some implementations of the first aspect, the second stripline includes multiple strip branches, and at least two striplines in the second stripline have different lengths.

[0030] In some implementations of the first aspect, the second stripline includes multiple strip segments, at least two of which have different impedances and phases.

[0031] In some implementations of the first aspect, the second strip line includes 3, 4, or 5 strip branches.

[0032] In some implementations of the first aspect, the fourth signal transmission structure and the fifth signal transmission structure are a fourth signal hole and a fifth signal hole.

[0033] In some implementations of the first aspect, the fourth signal hole and the fifth signal hole are connected in the first direction.

[0034] In some implementations of the first aspect, the third dielectric layer is a third dielectric substrate, and the fourth dielectric layer is a fourth dielectric substrate.

[0035] In some implementations of the first aspect, a first distance is spaced between the first dielectric substrate and the third dielectric substrate, a third distance is spaced between the third dielectric substrate and the fifth dielectric substrate, a fourth distance is spaced between the fifth dielectric substrate and the fourth dielectric substrate, and a fifth distance is spaced between the fourth dielectric substrate and the second dielectric substrate, wherein at least two of the first distance, the third distance, the fourth distance and the fifth distance are different.

[0036] In the above technical solution, the filtering range of the filter can be adjusted by changing the distance.

[0037] In some implementations of the first aspect, the filter further includes shielding structures disposed on the fourth and fifth dielectric substrates, the shielding structures comprising a plurality of shielding holes.

[0038] In a second aspect, a filtered antenna is provided, including the filter described in the first aspect or any possible implementation thereof.

[0039] Thirdly, a communication device is provided, including the filter described in the first aspect or any possible implementation thereof. Attached Figure Description

[0040] Figure 1 is a schematic diagram of a planar microstrip filter.

[0041] Figure 2 is a schematic perspective view of the filter provided in this application.

[0042] Figure 3 is a schematic perspective view of a possible filter provided in this application.

[0043] Figure 4 is a top view of each layer of the three-layer structure of the filter shown in Figure 3.

[0044] Figure 5 is a simulation diagram of the filtering effect of the filter proposed in this application.

[0045] Figure 6 is a schematic perspective view of another possible filter provided in this application.

[0046] Figure 7 is a top view of each layer of the four-layer structure of the filter shown in Figure 6.

[0047] Figure 8 is a schematic perspective view of another possible filter provided in this application.

[0048] Figure 9 is a top view of each layer of the five-layer structure of the filter shown in Figure 8.

[0049] Figure 10 is a simulation diagram of the filtering effect of the filter proposed in this application.

[0050] Figure 11 is a schematic perspective view of another filter proposed in this application.

[0051] Figure 12 is a schematic perspective view of a filter antenna proposed in this application. Detailed Implementation

[0052] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0053] The technical solutions of this application embodiment can be applied to various communication devices, such as wireless communication devices including filters. For example, the dielectric filter provided in this application embodiment can be applied to network devices or terminal devices in wireless communication systems, such as network devices or terminal devices in 5th generation (5G) systems or new radio (NR) systems, such as base stations, baseband units (BU), distributed units (DU), radio units (RU), etc., and can also be applied to communication devices in future communication systems, etc.

[0054] Traditional filters include, but are not limited to, planar microstrip filters and electromagnetic bandgap (EBG) filters. Figure 1 shows a schematic diagram of a planar microstrip filter. As shown in Figure 1, 1 and 2 are the input and output ports of the filter, respectively. The part filled with slashes represents the microstrip line. It can be seen that for a planar microstrip filter, the microstrip line is a planar structure. The microstrip line leading out from input port 1 usually has a certain length, which will cause a certain distance between the output port 1 and the input port 2 of the filter, thus making it difficult to significantly reduce the planar size of the filter. In addition, for an EBG filter, the EBG structure is a periodic structure, so the filter also needs a relatively large size to achieve good performance. Therefore, when the distance between the antenna elements in an array antenna is small, there is not enough space to place the above-mentioned filters, which limits their application.

[0055] In view of this, this application proposes a filter that can solve the problems of large size and difficulty in integration of current filters. The various embodiments provided in this application will be described in detail below with reference to the accompanying drawings.

[0056] Figure 2 is a schematic perspective view of the filter proposed in an embodiment of this application. It should be understood that Figure 2 is only a schematic diagram for ease of understanding, and the specific structure of the actual product is not limited to Figure 2.

[0057] As shown in Figure 2, the filter includes a first dielectric substrate 21, a filter structure 1, and a second dielectric substrate 22 stacked in a first direction, with the filter structure 1 located between the first dielectric substrate 21 and the second dielectric substrate 22. The first dielectric substrate 21 has a first signal transmission structure 31 for inputting a received first signal to the filter structure 1. The second dielectric substrate 22 has a second signal transmission structure 32 for outputting the signal obtained by the filter structure 1 after filtering the first signal.

[0058] It is understood that the signal transmission structure in this application is a structure that can realize signal input and / or output. Furthermore, the signal transmission structure is isolated from the dielectric substrate it resides on, and there is no electrical connection between them.

[0059] Optionally, the specific form of the signal transmission structure in this application is a signal hole, and the signal hole is a through hole. Furthermore, this application does not specifically limit how signal transmission is achieved between the signal transmission structures.

[0060] Optionally, the dielectric substrate in this application is a printed circuit board (PCB) dielectric substrate.

[0061] Optionally, there is a gap between the first dielectric substrate 21 and the filter structure 1, and a gap between the filter structure 1 and the second dielectric substrate 22.

[0062] In the above scheme, the first signal transmission structure 31 in the filter serves as the signal input port for the first signal, and the second signal transmission structure 32 serves as the signal output port for the filtered first signal. Since the first signal transmission structure 31 and the second signal transmission structure 32 are stacked in the first direction, the signal input and output ports of the filter can be vertically integrated, resulting in a smaller filter size and easier integration. For example, in the prior art, because microstrip lines typically have a certain length, there is a certain distance between the output port and the input port of the filter, making it difficult to significantly reduce the planar size of the filter. Based on the embodiments provided in this application, by arranging the first and second signal transmission structures in the first direction, the distance between the input and output ports of the filter is not affected by the length of the microstrip line. Therefore, the overall size of the filter can be significantly reduced, allowing the filter to have a very small size, making it easy to apply in filtered antenna design and achieve high isolation between antenna elements.

[0063] In one possible design, as shown in Figure 3, the filter structure 1 includes a third dielectric substrate 23, on which a third signal transmission structure 33 and a first stripline are disposed. The first dielectric substrate 21, the second dielectric substrate 22, and the third dielectric substrate 23 are all parallel to a first plane, which is the plane containing the first dielectric substrate. Figure 4 is a top view of each layer of the three-layer filter structure shown in Figure 3. The first layer includes the first dielectric substrate 21 and the first signal transmission structure 31; the second layer includes the third dielectric substrate 23, the third signal transmission structure 33, and the first stripline. For example, the first stripline includes at least one strip branch, such as the strip branches 51, 52, 53, and 54 shown in Figure 4; the third layer includes the second dielectric substrate 22 and the second signal transmission structure 32.

[0064] For example, a stub in the first stripline is connected to the third signal transmission structure 33. This connection can be direct or indirect. For instance, a direct connection between a stub and the third signal transmission structure 33 could be that the stub originates from the third signal transmission structure 33 (e.g., stubs 52 and 54 in Figure 4). Alternatively, an indirect connection between a stub and the third signal transmission structure 33 could be that the stub originates from another stub originating from the third signal transmission structure 33 (e.g., stubs 51 and 53 in Figure 4, which can be considered as originating from stub 54).

[0065] For example, the first strip line includes multiple strip branches, and at least two strip lines in the first strip line have different lengths.

[0066] For example, the first stripline includes multiple strip branches, and at least two strip branches in the first stripline have different phases Z and θ.

[0067] As an example, the stripe segments included in the first stripline in Figure 4 are merely illustrative. For instance, the first stripline may also include three or five stripe segments. It is understood that in practice, the filtering range can be adjusted by regulating the size and number of stripe segments in the first stripline. Optionally, as shown in Figure 4, the filter further includes shielding structures respectively disposed on the first dielectric substrate 21, the second dielectric substrate 22, and the third dielectric substrate 23, the shielding structures including multiple shielding holes 61. In this application, the shielding structures can ensure low-loss transmission of radio frequency signals and can be used to isolate circuit board areas operating at different frequencies.

[0068] Optionally, the third dielectric substrate 23 may not be included in the second layer structure shown in Figure 4. For example, the second layer structure includes a third signal transmission structure 33 and a first stripline. For instance, when the third dielectric substrate 23 is absent, the second layer structure can be implemented using machining processes.

[0069] The filtering process of the first signal is described below based on the filter shown in Figure 3. The third signal transmission structure 33 is used to receive the first signal from the first signal transmission structure 31 and transmit it to the first stripline; the first stripline is used to filter the first signal to obtain the second signal; the third signal transmission structure 33 is also used to output the second signal to the second signal transmission structure 32, and then the second signal transmission structure 32 outputs the second signal as the signal output port of the filter.

[0070] For example, as shown in Figure 3, the specific forms of the first signal transmission structure 31, the second signal transmission structure 32, and the third signal transmission structure 33 can be signal holes, which are respectively referred to as the first signal hole, the second signal hole, and the third signal hole.

[0071] For example, the first signal hole, the second signal hole, and the third signal hole are connected in the first direction. For instance, when the first signal transmission structure 31, the second signal transmission structure 32, and the third signal transmission structure 33 are signal holes, this application can realize signal transmission based on traditional PCB manufacturing processes, or it can also realize signal transmission through machining or other manufacturing processes.

[0072] For example, the first dielectric substrate 21 and the third dielectric substrate 23 are spaced at a distance of #11, and the third dielectric substrate 23 and the second dielectric substrate 22 are spaced at a distance of #12. Distances #11 and #12 may be the same or different. It is understood that changing the first distance and / or the second distance can change the filtering range of the first stripline.

[0073] Figure 5 shows a simulation of the filtering effect of the filter proposed in Figure 3. The horizontal axis represents frequency (in GHz), and the vertical axis represents amplitude (in dB). Line #1 represents the reflection amplitude at the signal input port (i.e., the first signal transmission structure), and line #2 represents the transmission loss from the signal input port to the signal output port (i.e., from the first signal transmission structure to the second signal transmission structure). It can be seen that the passband of the filter in Figure 5 is 28–30 GHz, corresponding to a reflection amplitude less than -10 dB and a transmission loss less than 0.2 dB. The stopband is 20–23 GHz, corresponding to a suppression level greater than 15 dB, and the out-of-band signal suppression reaches its maximum at 21.6 GHz, at 50.38 dB. In short, in the passband range of 28–30 GHz, the signal is reflected less and the transmission loss is lower; in the stopband range of 20–23 GHz, the signal is reflected more and the transmission loss is greater.

[0074] In another possible design, as shown in Figure 6, the filter structure 1, based on Figure 3, further includes a fourth dielectric substrate 24. The fourth dielectric substrate 24 has a fourth signal transmission structure 34 and a second stripline disposed thereon. The fourth dielectric substrate 24 is located between the third dielectric substrate 23 and the second dielectric substrate 22. The first dielectric substrate 21, the second dielectric substrate 22, the third dielectric substrate 23, and the fourth dielectric substrate 24 are all parallel to a first plane, which is the plane containing the first dielectric substrate. Figure 7 is a top view of each layer of the four-layer structure of the filter shown in Figure 6. The first layer structure includes a first dielectric substrate 21 and a first signal transmission structure 31; the second layer structure includes a third dielectric substrate 23, a third signal transmission structure 33, and a first stripline (for example, the first stripline includes at least one stripline branch, such as stripline branches 51, 52, 53, and 54 in FIG6); the third layer structure includes a fourth dielectric substrate 24, a fourth signal transmission structure 34, and a second stripline (for example, the second stripline may include at least one stripline branch, such as stripline branches 55, 56, 57, and 58 in FIG6); and the fourth layer structure includes a second dielectric substrate 22 and a second signal transmission structure 32.

[0075] For example, the strip stub in the second stripline is connected to the fourth signal transmission structure 34. This connection can be a direct connection or an indirect connection, as described above, and will not be repeated here.

[0076] For example, the second band includes multiple banded branches, and at least two bands in the second band have different lengths.

[0077] For example, the second bandline includes multiple banded branches, and at least two banded branches in the second bandline have different phases Z and θ.

[0078] As an example, the striped branches included in the first and second stripes in Figure 7 are merely illustrative. For instance, the first or second stripe may also include 3 or 5 striped branches. It is understood that in practice, the filtering range can be adjusted by regulating the size and number of striped branches in the first and / or second stripes.

[0079] Optionally, as shown in Figure 7, the filter further includes shielding structures respectively disposed on the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the fourth dielectric substrate, the shielding structures including multiple shielding holes 61.

[0080] Optionally, the third dielectric plate 23 may not be provided in the second layer structure shown in Figure 7, and / or the fourth dielectric plate 24 may not be provided in the third layer structure.

[0081] It is understandable that the filter structure 1 in this scheme can also include multi-layer structures similar to the second or third layer structure, thereby realizing cascaded filtering with more layers, which will not be elaborated here.

[0082] The filtering process of the first signal is described below based on the filter shown in Figure 6. The third signal transmission structure 33 is used to receive the first signal from the first signal transmission structure 31 and transmit it to the first stripline; the first stripline is used to filter the first signal to obtain the second signal; the third signal transmission structure 33 is also used to output the second signal to the fourth signal transmission structure 34; the fourth signal transmission structure 34 is used to receive the second signal from the third signal transmission structure 33 and transmit it to the second stripline; the second stripline is used to filter the second signal to obtain the third signal; the fourth signal transmission structure 34 is also used to output the third signal to the second signal transmission structure 32, and then the second signal transmission structure 32 outputs the third signal as the signal output port of the filter.

[0083] For example, as shown in Figure 6, the specific forms of the first signal transmission structure 31, the second signal transmission structure 32, the third signal transmission structure 33, and the fourth signal transmission structure 34 are signal holes, which are respectively referred to as the first signal hole, the second signal hole, the third signal hole, and the fourth signal hole.

[0084] For example, the first signal hole, the second signal hole, the third signal hole, and the fourth signal hole are connected in the first direction.

[0085] For example, the spacing between the first dielectric substrate 21 and the third dielectric substrate 23 is #21, the spacing between the third dielectric substrate 23 and the fourth dielectric substrate 24 is #22, and the spacing between the fourth dielectric substrate 24 and the second dielectric substrate 22 is #23. The above three distances may all be the same, or at least two of the above three distances may be different.

[0086] The filter described above, with its two-layer structure (i.e., the third and fourth layers) incorporating striplines, can be cascaded for filtering. The second signal, obtained after filtering the first stripline in the third layer, can be transmitted through the third signal transmission structure 33 and the fourth signal transmission structure 34 to the second stripline for further filtering. This cascading approach allows for flexible adjustment of the passband and stopband ranges, expanding the filter's bandwidth and enabling effective suppression of out-of-band signals within a relatively small size, thus improving the filtering performance.

[0087] In another possible design, as shown in Figure 8, the filter structure 1, based on Figure 6, further includes a fifth dielectric substrate 25. A fifth signal transmission structure 35 is disposed on the fifth dielectric substrate 25. The fifth dielectric substrate 25 is located between the third dielectric substrate 23 and the fourth dielectric substrate 24. The first dielectric substrate 21, the second dielectric substrate 22, the third dielectric substrate 23, the fourth dielectric substrate 24, and the fourth dielectric substrate 25 are all parallel to a first plane, which is the plane containing the first dielectric substrate. Figure 9 is a top view of each of the five layers in the filter structure shown in Figure 8. The first layer structure includes a first dielectric substrate 21 and a first signal transmission structure 31; the second layer structure includes a third dielectric substrate 23, a third signal transmission structure 33, and a first stripline (for example, the first stripline includes at least one stripline branch, such as stripline branches 51, 52, 53, and 54 in FIG6); the third layer structure includes a fifth dielectric substrate 25 and a fifth signal transmission structure 35; the fourth layer structure includes a fourth dielectric substrate 24, a fourth signal transmission structure 34, and a second stripline (for example, the second stripline may include at least one stripline branch, such as stripline branches 55, 56, 57, and 58 in FIG6); and the fifth layer structure includes a second dielectric substrate 22 and a second signal transmission structure 32.

[0088] Optionally, as shown in Figure 9, the filter further includes shielding structures respectively disposed on the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the fourth dielectric substrate, the shielding structures including multiple shielding holes 61.

[0089] The filtering process of the first signal is described below based on the filter shown in Figure 9. The third signal transmission structure 33 receives the first signal from the first signal transmission structure 31 and transmits it to the first stripline; the first stripline filters the first signal to obtain the second signal; the third signal transmission structure 33 also outputs the second signal. The fifth signal transmission structure 35 receives the second signal from the third signal transmission structure 33 and transmits it to the fourth signal transmission structure 34; the fourth signal transmission structure 34 receives the second signal from the third signal transmission structure 33 and transmits it to the second stripline; the second stripline filters the second signal to obtain the third signal; the fourth signal transmission structure 34 also outputs the third signal. Here, the fourth signal transmission structure 34 outputting the third signal can be understood as the fourth signal transmission structure 34 outputting the third signal to the second signal transmission structure 32, after which the second signal transmission structure 32 acts as the signal output port of the filter, outputting the third signal.

[0090] For example, as shown in Figure 9, the specific forms of the first signal transmission structure 31, the second signal transmission structure 32, the third signal transmission structure 33, the fourth signal transmission structure 34, and the fifth signal transmission structure 35 are signal holes, which are respectively referred to as the first signal hole, the second signal hole, the third signal hole, the fourth signal hole, and the fifth signal hole.

[0091] For example, the first signal hole, the second signal hole, the third signal hole, the fourth signal hole, and the fifth signal hole are connected in the first direction.

[0092] For example, the spacing between the first dielectric substrate 21 and the third dielectric substrate 23 is #31, the spacing between the third dielectric substrate 23 and the fifth dielectric substrate 25 is #32, the spacing between the fifth dielectric substrate 25 and the fourth dielectric substrate 24 is #33, and the spacing between the fourth dielectric substrate 24 and the second dielectric substrate 22 is #34. The above four distances may all be the same, or at least two of the above four distances may be different.

[0093] As can be seen, the filter shown in Figure 8 adds a fifth dielectric plate 25 between the third dielectric plate 23 and the fourth dielectric plate 24 of the filter shown in Figure 6. This can isolate the first stripline and the second stripline, avoid coupling between the striplines, and reduce the design complexity.

[0094] Figure 10 is a simulation diagram of the filtering effect of the filter shown in Figure 8. The horizontal axis represents frequency (in GHz), and the vertical axis represents amplitude (in dB). Line #1 represents the reflection amplitude at the signal input port (i.e., the first signal transmission structure), and line #2 represents the transmission loss from the signal input port to the signal output port (i.e., from the first signal transmission structure to the second signal transmission structure). It can be seen that the passband of the filter structure in this embodiment is 28–31 GHz, corresponding to a reflection amplitude less than -10 dB and a transmission loss less than 0.2 dB. The stopband is 17–25 GHz, corresponding to a suppression level greater than 15 dB, and the out-of-band signal suppression reaches its maximum of 60 dB at 21.9 GHz. Compared to the filtering effect of the filter structure in Figure 5, the cascaded filter has a passband range that is 1 GHz wider and a stopband range that is 5 GHz wider, further improving the filtering effect.

[0095] As can be seen, each layer of the filters shown in Figures 3, 6, and 8 includes a signal transmission structure. If we consider all the signal transmission structures in all layers of each figure as a set of signal transmission structures, then optionally, each figure can also include multiple sets of corresponding signal transmission structures. Taking Figure 8 as an example, based on the filter shown in Figure 8, there can be another set of signal transmission structures, as shown in Figure 11. In Figure 11, each of the two dashed boxes corresponds to a set of signal transmission structures.

[0096] It is understood that the filters proposed in the embodiments of this application are merely illustrative examples, and any variations of the above structure are applicable to this application.

[0097] This application also provides a filtering antenna, which includes an antenna and a filter as described in the previous embodiment. The following example is illustrated with reference to Figure 12. As shown in Figure 12, the filtering antenna includes antenna 71 and antenna 72, where antenna 71 is a receiving antenna and antenna 72 is a transmitting antenna, operating at different frequencies. Furthermore, filters as shown in Figure 11 are integrated below antennas 71 and 72, respectively. The filters composed of dielectric substrates 21′ to 25′ and 21″ to 25″ are similar to the filters composed of dielectric substrates 21 to 25 in Figure 11 above, and will not be described again here. The transmitting and receiving antennas in the filtering antenna proposed in this application can be vertically integrated with the filter proposed in this application, which not only reduces the size of the filtering antenna but also achieves high isolation between antenna elements.

[0098] For example, to reduce design complexity, the filters integrated under each antenna in the filtering antenna consist of N layers, where N is an integer greater than or equal to 3. For instance, the filters integrated under antennas 71 and 72 each consist of 5 layers.

[0099] For example, based on actual filtering requirements, striplines need to be set in the dielectric substrates 23″ and 24″ below antenna 72 to achieve cascaded filtering. However, the stripline set in the dielectric substrate 23′ below antenna 71 in the filtering antenna can already meet the filtering requirements, so the stripline in the dielectric substrate 24″ below antenna 71 does not need to be set.

[0100] This application also provides a power amplifier that includes the filter described in the above embodiment.

[0101] The power amplifier may include a pre-stage filter, an input matching circuit, a bias circuit, a transistor, an output matching circuit, and a post-stage filter. The pre-stage filter is connected to the input matching circuit, the transistor is connected to the input matching circuit, the bias circuit, and the output matching circuit, and the output matching circuit is connected to the post-stage filter. For example, the filter provided in this embodiment can be used as a post-stage filter to reduce noise generated when a signal passes through the power amplifier.

[0102] This application also provides a communication device, which includes the filter described in the above embodiments.

[0103] It is understood that the communication device can be a network device, such as a base station. A base station can broadly encompass, or be replaced by, various names including: NodeB, evolved NodeB (eNB), next-generation NodeB (gNB), relay station, access point, transmitting and receiving point (TRP), transmitting point (TP), master station, auxiliary station, motor slide retainer (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, baseband unit (BU), radio unit (RU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. A base station can be a macro base station, micro base station, relay node, donor node, or a combination thereof. A base station can also refer to a communication module, modem, or chip installed within the aforementioned equipment or apparatus. A base station can also be a mobile switching center, a device that performs base station functions in device-to-device (D2D), vehicle-to-everything (V2X), and machine-to-machine (M2M) communications, a network-side device in future communication networks, or any other device performing base station functions. Base stations can support networks using the same or different access technologies. The embodiments of this application do not limit the specific technologies or device forms used in the network equipment.

[0104] The communication device can also be a terminal device. Examples of current terminal devices include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving vehicles, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, wearable devices, terminal devices in 5G networks, or future public land mobile communication networks. Terminal devices in a network (PLMN), etc., are not limited to this in the embodiments of this application.

[0105] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims and the specification.

Claims

1. A filter, characterized in that, include: A first dielectric substrate, a filter structure, and a second dielectric substrate are stacked in a first direction, with the filter structure located between the first dielectric substrate and the second dielectric substrate. A first signal transmission structure is provided on the first dielectric substrate, which is used to input the received first signal to the filtering structure. The second medium board is provided with a second signal transmission structure, which is used to output the signal obtained by the filtering structure filtering the first signal.

2. The filter according to claim 1, characterized in that, The filtering structure includes a third dielectric layer, on which a third signal transmission structure and a first stripline are disposed. The first stripline is used to filter the first signal to obtain a second signal. The third signal transmission structure is used to receive the first signal from the first signal transmission structure and to output the second signal.

3. The filter according to claim 2, characterized in that, The first stripline includes at least one strip branch, and the strip branch in the first stripline is connected to the third signal transmission structure.

4. The filter according to claim 3, characterized in that, The first strip line includes multiple strip-shaped branches, and at least two strip lines in the first strip line have different lengths.

5. The filter according to claim 3 or 4, characterized in that, The first stripline includes multiple strip segments, and at least two strip segments in the first stripline have different impedances and phases.

6. The filter according to any one of claims 3 to 5, characterized in that, The first strip line includes 3, 4, or 5 strip branches.

7. The filter according to any one of claims 2 to 6, characterized in that, The first signal transmission structure, the second signal transmission structure, and the third signal transmission structure are respectively a first signal hole, a second signal hole, and a third signal hole.

8. The filter according to claim 7, characterized in that, The first signal hole, the second signal hole, and the third signal hole are connected in the first direction.

9. The filter according to any one of claims 2 to 8, characterized in that, The third dielectric layer is a third dielectric plate.

10. The filter according to claim 9, characterized in that, The first dielectric substrate and the third dielectric substrate are spaced apart by a first distance, and the third dielectric substrate and the second dielectric substrate are spaced apart by a second distance, wherein the first distance and the second distance are not the same.

11. The filter according to claim 9 or 10, characterized in that, The filter also includes: The shielding structures are respectively disposed on the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate, and the shielding structures include a plurality of shielding holes.

12. The filter according to any one of claims 2 to 11, characterized in that, The filtering structure further includes a fourth dielectric layer, on which a fourth signal transmission structure and a second stripline are disposed. The second stripline is used to filter the second signal again to obtain a third signal. The fourth signal transmission structure is used to receive the second signal and output the third signal.

13. The filter according to claim 12, characterized in that, The filtering structure further includes a fifth dielectric substrate, on which a fifth signal transmission structure is disposed. The fifth dielectric substrate is located between the third dielectric layer and the fourth dielectric layer. The fifth signal transmission structure is used to receive the second signal and to transmit the second signal to the fourth signal transmission structure.

14. The filter according to claim 12 or 13, characterized in that, The second stripline includes at least one strip branch, and the strip branch in the second stripline is connected to the fourth signal transmission structure.

15. The filter according to claim 14, characterized in that, The second band includes multiple banded branches, and at least two of the second bands have different lengths.

16. The filter according to claim 14 or 15, characterized in that, The second stripline includes multiple strip segments, and at least two strip segments in the second stripline have different impedances and phases.

17. The filter according to any one of claims 14 to 16, characterized in that, The second banded line includes 3, 4, or 5 banded nodes.

18. The filter according to claim 13, characterized in that, The fourth signal transmission structure and the fifth signal transmission structure are the fourth signal hole and the fifth signal hole.

19. The filter according to claim 18, characterized in that, The fourth signal hole and the fifth signal hole are connected in the first direction.

20. The filter according to claim 13, characterized in that, The third dielectric layer is a third dielectric plate, and the fourth dielectric layer is a fourth dielectric plate.

21. The filter according to claim 20, characterized in that, The first dielectric substrate and the third dielectric substrate are spaced apart by a first distance, the third dielectric substrate and the fifth dielectric substrate are spaced apart by a third distance, the fifth dielectric substrate and the fourth dielectric substrate are spaced apart by a fourth distance, and the fourth dielectric substrate and the second dielectric substrate are spaced apart by a fifth distance, wherein at least two of the first distance, the third distance, the fourth distance and the fifth distance are different.

22. The filter according to claim 20 or 21, characterized in that, The filter also includes: The shielding structures are respectively disposed on the fourth dielectric plate and the fifth dielectric plate, and the shielding structures include a plurality of shielding holes.

23. A filter antenna, characterized in that, The filtered antenna includes a filter as described in any one of claims 1 to 22.

24. A communication device, characterized in that, The communication device includes a filter as described in any one of claims 1 to 22.

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