Multiband filter and communication device

Abstract

The invention relates to a multiband filter and a communication device. The multi-band filter includes a plurality of multi-mode resonators, where each of the multi-mode resonators is a microstrip line resonator, the microstrip line resonator including a ground and two or more non-ground branches for implementing a plurality of modes.

Description

Technical Field

[0001] The present disclosure relates generally to components of a communication device, and more particularly, to a multi-band filter and a communication device having the multi-band filter. Background Art

[0002] This section introduces aspects that may help to better understand the present disclosure. Therefore, the statements in this section should be read in this light and should not be understood as an admission of content in the prior art or content that does not exist in the prior art.

[0003] The base station (BS) is an important part of the mobile communication system and may include a radio unit (RU) and an antenna unit (AU). Considering installation / fixation / occupancy, smaller volume and lighter weight are always important evolution directions of BS design, including traditional base stations, street macro, micro, small cells and advanced antenna systems (AAS).

[0004] With the development of the fifth generation (5G) communication, multiple input multiple output (MIMO) technology is widely used in Sub-6GHz BS products, in which a large number of filters need to be integrated / embedded in AU or RU. There are many filter solutions that can be applied to BS, such as ceramic waveguide (CWG) filters, coaxial metal cavity filters, monolithic filters, bulk acoustic wave (BAW) filters, surface acoustic wave (SAW) filters, etc.

[0005] In order to obtain size / weight and cost benefits, especially good performance, a small size metal filter is an irreplaceable solution. It can be soldered to the radio motherboard (MOB), antenna calibration (AC) board or power splitter board, which will reduce the size and weight of the radio. It can also be connected to other radio components such as macro stations through connectors.

[0006] In order to further reduce the size and weight of radios based on small-size metal filter technology, integrating two different passbands or multiple passbands into one radio is a new popular way. Different frequency bands of time division duplex (TDD) radios can work together, which will transmit and receive more signals in different time zones. For the upcoming 5G frequency division duplex (FDD) system, suitable duplexers are also important for reducing the size of radios. Different frequency bands of FDD radios can also work together, with some bands used for signal reception and others for signal transmission.

[0007] Existing solutions for small-size metal filters usually use metal-integrated air microstrip line resonators to reduce size / weight compared to traditional coaxial resonators. Traditional multi-band and FDD FUs always combine two or more filters of different frequency bands through a common cavity to obtain a duplexer or multiplexer. However, when two or more filters are combined, the FU may become large and heavy, and the FU is difficult to solder to the printed circuit board (PCB).

[0008] Therefore, it is important to find a better way to combine two or more different frequency bands into one unit. Summary of the invention

[0009] This Summary is provided to introduce selected concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0010] One of the objects of the present disclosure is to provide a small size multi-band filter which can further reduce radio size / weight and cost.

[0011] According to a first aspect of the present disclosure, there is provided a multi-band filter including a plurality of multi-mode resonators, wherein each of the multi-mode resonators is a microstrip line resonator including a ground portion and two or more non-ground branches for realizing a plurality of modes.

[0012] In one embodiment of the present disclosure, the multi-band filter further includes: a chassis, the chassis defining a cavity, wherein the multi-mode resonator is arranged in the cavity, and the ground portion is connected to the chassis.

[0013] In an embodiment of the present disclosure, the multi-mode resonator is manufactured integrally with the chassis.

[0014] In another embodiment of the present disclosure, the multi-mode resonator is produced separately from the chassis and is connected to the chassis by brazing or welding.

[0015] In an embodiment of the present disclosure, the chassis and / or the microstrip line resonator are made of a metal or a non-metal substrate with a metallized surface.

[0016] In another embodiment of the present disclosure, the multi-band filter further comprises a multi-layer circuit board, wherein the multi-mode resonator is arranged on an intermediate layer, the intermediate layer is sandwiched between an upper conductive layer and a lower conductive layer, and is surrounded by metallized vias for electrically connecting the upper conductive layer and the lower conductive layer.

[0017] In an embodiment of the present disclosure, a ground portion of each of the multi-mode resonators is connected to one of the metallized vias.

[0018] In an embodiment of the present disclosure, the intermediate layer is made of ceramic, and the multi-mode resonator is formed on the intermediate layer by a low temperature co-fired ceramic (LTCC) technology or a high temperature co-fired ceramic (HTCC) technology.

[0019] In an embodiment of the present disclosure, the multi-layer circuit board is a printed circuit board assembly (PCBA), and the multi-mode resonator is laminated on an intermediate layer.

[0020] In an embodiment of the present disclosure, at least one multi-mode resonator is formed across two or more layers, and portions of the at least one multi-mode resonator on different layers are connected by metallized vias passing through the layers.

[0021] In an embodiment of the present disclosure, one of the plurality of multi-mode resonators is connected to a first radio frequency (RF) port, and another one of the plurality of multi-mode resonators is connected to a second RF port.

[0022] In another embodiment of the present disclosure, one of the plurality of multi-mode resonators is connected to the first RF port, and another of the plurality of multi-mode resonators is coupled to a plurality of single-mode resonators, each of which is connected to a corresponding one of the plurality of second RF ports.

[0023] In the embodiments of the present disclosure, the multi-band filter can be tuned during production by tuning screws or tuning plates.

[0024] In one embodiment of the present disclosure, the frequencies and / or couplings in different modes may be tuned separately.

[0025] In an embodiment of the present disclosure, the non-grounded branches of the microstrip line resonator extend substantially in the same plane.

[0026] In one embodiment of the present disclosure, at least one of the non-grounding branches may be folded and / or may be provided with an enlarged end.

[0027] In an embodiment of the present disclosure, at least one of the non-ground branches may be formed with a hole or a recess.

[0028] In an embodiment of the present disclosure, at least two non-grounded branches of the microstrip line resonator extend substantially parallel to each other and have different lengths in the extending direction.

[0029] In one embodiment of the present disclosure, the grounding portion of the microstrip line resonator is disposed at a junction of the two or more non-grounding branches.

[0030] In an embodiment of the present disclosure, a plastic material is added on at least one side of the microstrip line resonator.

[0031] In an embodiment of the present disclosure, a metal microstrip line low-pass filter (LPF) is provided at an input region or an output region of the multi-band filter.

[0032] According to a second aspect of the present disclosure, there is provided a communication device comprising at least one multi-band filter according to the first aspect.

[0033] In an embodiment of the present disclosure, the multi-band filter is soldered on the radio board or antenna board, or connected to the radio board or antenna board through an RF connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] These and other objects, features and advantages of the present disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in conjunction with the accompanying drawings, in which:

[0035] Figure 1A shows a dual-mode resonator in a dual-band filter according to a first embodiment of the present disclosure, Figure 1B shows the electric and magnetic fields in the first mode, Figure 1C The electric and magnetic fields in the second mode are shown;

[0036] Figure 2A is a perspective view of a dual-band filter according to a first embodiment, Figure 2B is the front view of the dual-band filter;

[0037] Figure 3 is a schematic diagram showing the topology of a dual-band filter according to a first embodiment;

[0038] Figure 4A and Figure 4B The simulated frequency response curves of the dual-band filter according to the first embodiment are shown respectively;

[0039] Figure 5 is a perspective view of a dual-band filter according to a second embodiment of the present disclosure;

[0040] Fig. 6A is a perspective view of a dual-band filter according to a third embodiment of the present disclosure, and Figure 6B is a schematic diagram showing a topological structure of a dual-band filter according to a third embodiment;

[0041] Figures 7A-7H Different variations of dual-mode resonators according to the present disclosure are shown;

[0042] Fig. 8A shows a triple-mode resonator in a triple-band filter according to a fourth embodiment of the present disclosure, Figure 8B shows the electric and magnetic fields in the first mode, Figure 8C shows the electric and magnetic fields in the second mode, Fig.8D The electric and magnetic fields in the third mode are shown;

[0043] Figures 9A-9D Different variations of a three-mode resonator according to the present disclosure are shown;

[0044] Fig. 10A 4 shows a quad-mode resonator in a quad-band filter according to a fifth embodiment of the present disclosure, Fig. 10B shows the electric and magnetic fields in the first mode, Fig. 10C shows the electric and magnetic fields in the second mode, Fig. 10D shows the electric and magnetic fields in the third mode, Fig. 10E The electric and magnetic fields in the fourth mode are shown;

[0045] Fig.11A and Fig. 11B shows different variations of a quad-mode resonator according to the present disclosure; and

[0046] Fig. 12A and Fig. 12B Another multi-band filter according to the present disclosure is shown. DETAILED DESCRIPTION

[0047] Embodiments of the present disclosure are described in detail in conjunction with the accompanying drawings. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and therefore implement the purpose of the present disclosure, rather than to imply any limitation on the scope of the present disclosure. References to features, advantages or similar language throughout this specification do not mean that all features and advantages that can be implemented with the present disclosure should be or are in any single embodiment of the present disclosure. On the contrary, the language related to features and advantages is understood to mean that the specific features, advantages or characteristics described in conjunction with the embodiments are included in at least one embodiment of the present disclosure. In addition, the described features, advantages and characteristics of the present disclosure may be combined in one or more embodiments in any suitable manner. Those skilled in the relevant art will recognize that the present disclosure can be practiced without one or more of the specific features or advantages of a specific embodiment. In other cases, additional features and advantages that may not be present in all embodiments of the present disclosure may be recognized in certain embodiments.

[0048] Generally, all terms used in this article will be interpreted according to their common meaning in the relevant technical field, unless different meanings are clearly given and / or implied from the context of their use. Unless otherwise clearly stated, all references to elements, equipment, components, devices, steps, etc. should be openly interpreted as referring to at least one instance of elements, equipment, components, devices, steps, etc. Any feature of any embodiment disclosed herein can be applied to any other embodiment where appropriate. Similarly, any advantage of any embodiment can be applied to any other embodiment, and vice versa. Other purposes, features and advantages of the attached embodiments will become apparent from the following description.

[0049] Figure 1A FIG. 2 shows a dual-mode resonator in a dual-band filter according to a first embodiment of the present disclosure. Figure 1A As shown, the dual-mode resonator is arranged in a cavity defined by a chassis. As an example, the chassis can be made of metal, such as aluminum, by an extrusion molding process. The chassis can also be made of a non-metallic substrate with a metallized surface. The dual-mode resonator is a microstrip line resonator, which can also be made of a metal or a non-metallic substrate with a metallized surface. The material of the dual-mode resonator can be the same as or different from the material of the chassis. The dual-mode resonator includes two non-grounded branches 1011, 1012 and a grounding portion 1013. The grounding portion 1013 is arranged at the junction of the two non-grounded branches 1011, 1012, and is connected to the chassis by brazing or welding.

[0050] In this embodiment, the grounding portion 1013 and the two non-grounding branches 1011 and 1012 extend in the same plane. The dual-mode resonator can be stamped from a metal sheet and have a uniform thickness. However, the present disclosure is not limited to this, and the grounding portion 1013 and the two non-grounding branches 1011 and 1012 can have different thicknesses. The two non-grounding branches 1011 and 1012 each have a connecting portion connected to the grounding portion 1013 and a main body portion perpendicular to the connecting portion. The main body portion of the non-grounding branch 1011 is parallel to the main body portion of the non-grounding branch 1012. In this connection, it can be said that the two non-grounding branches 1011 and 1012 extend substantially parallel to each other. Preferably, the main bodies of the two non-grounding branches 1011 and 1012 have different lengths in the extension direction. The width of the main body of one grounding branch 1011 in a direction perpendicular to the extension direction and the thickness direction may be the same as or different from the width of the main body of the other grounding branch 1012 , and greater than the width of the connecting portion of the non-grounding branches 1011 , 1012 .

[0051] Figure 1B shows the electric field (left) and magnetic field (right) of a dual-mode resonator in the first mode, Figure 1CThe electric field (left) and magnetic field (right) of a dual-mode resonator in the second mode are shown. In this embodiment, the first mode is realized by the entire resonator and the second mode is realized by the bottom half of the resonator. The frequency and / or coupling in the first mode can be tuned on the top side of the resonator. The frequency and / or coupling in the second mode can be tuned on the bottom side of the resonator. For example, tuning can be performed by tuning screws or tuning plates.

[0052] Figure 2A is a perspective view of a dual-band filter according to a first embodiment, and Figure 2B 2 is a front view of a dual-band filter. The dual-band filter 2 in this embodiment is a three-pole filter having three dual-mode resonators 201, 202, and 203. Each of the three dual-mode resonators 201, 202, and 203 is as shown in FIG. Figure 1A Configuration as shown. An isolation wall 204 is provided between the dual-mode resonator 201 and the dual-mode resonator 202, and another isolation wall 205 is provided between the dual-mode resonator 202 and the dual-mode resonator 203. The isolation walls 204, 205 can control the coupling between adjacent resonators. The isolation walls 204, 205 and the grounding part of the three dual-mode resonators 201, 202, 203 are connected to a chassis 206, which can be made of the same or different material as the resonator. The material can be a metal or a non-metallic substrate with a metallized surface.

[0053] The dual-band filter 2 is provided with two RF ports 207, 208 on two opposite sides of the chassis 206. The dual-mode resonator 201 is connected to the first RF port 207, and the dual-mode resonator 203 is connected to the second RF port 208. The positions of the two RF ports 207, 208 can be adjusted according to actual requirements. The dual-band filter 2 can be connected to other radio components through RF connectors provided at the two RF ports 207, 208. In other embodiments, the RF connector can be omitted, and the dual-band filter can be directly soldered on the radio board or antenna board through the pads.

[0054] To further reduce the filter size, plastic material may be added on the top and / or bottom sides of each of the dual mode resonators 201, 202, 203. The plastic material will result in a higher dielectric constant than the air in the cavity defined by the chassis 206.

[0055] Figure 3 It is shown Figure 2A and Figure 2B The schematic diagram of the topology of the dual-band filter 2 is shown. Figures 1A to 1CAs described above, each of the three dual-mode resonators 201, 202, 203 has two different modes. Modes 1', 2', 3' (first modes) of the three dual-mode resonators 201, 202, 203 are coupled to realize the first band of the dual-band filter 2, and modes 1", 2", 3" (second modes) of the three dual-mode resonators 201, 202, 203 are coupled to realize the second band of the dual-band filter 2. Figure 3 Port 1 in corresponds to Figure 2A and 2B RF port 207, and Figure 3 Port 2 in corresponds to Figure 2A and 2B RF port 208 in.

[0056] It will be appreciated that more dual-mode resonators can be added to obtain a dual-band filter with more poles.

[0057] Figure 4A The simulated frequency response curve of the dual-band filter according to the first embodiment is shown. Band 1 (first band) is a lower frequency band realized by modes 1', 2', 3' (first mode) of the three dual-mode resonators 201, 202, 203, and Band 2 (second band) is a higher frequency band realized by modes 1", 2", 3" (second mode) of the three dual-mode resonators 201, 202, 203.

[0058] Figure 4B The far-end harmonic is shown, which is about three times the lower frequency mode of the dual-band filter. In order to obtain better far-end attenuation, a metal microstrip line LPF can be set at the input region or output region of the dual-band filter.

[0059] Figure 5 2 is a perspective view of a dual-band filter 2' according to a second embodiment of the present disclosure. The second embodiment differs from the first embodiment described above in that three dual-mode resonators are integrated with a chassis and produced at one time to form a main body 212, and then connected to a separately produced cover plate 211 by brazing or welding. Two RF ports 213, 214 are provided on two opposite sides of the main body 212.

[0060] Fig. 6A3 is a perspective view of a dual-band filter according to a third embodiment of the present disclosure. Like the dual-band filter in the first or second embodiment, the dual-band filter 3 in the third embodiment also has three dual-mode resonators 301, 302, 303 and two isolation walls 306, 307. The main difference between the third embodiment and the first embodiment is that two single-mode resonators 304, 305 are arranged adjacent to the dual-mode resonator 303 and coupled to the dual-mode resonator 303. An isolation wall 308 is arranged between the dual-mode resonator 303, the single-mode resonator 304 and the single-mode resonator 305 to isolate the two single-mode resonators 304, 305 and control the coupling between the two single-mode resonators 304, 305 and the dual-mode resonator 303. The dual-mode resonator 301 is connected to the first RF port 311. The single-mode resonator 304 is connected to the second RF port 312. The single-mode resonator 305 is connected to the third RF port 313. Therefore, the dual-band filter 3 in the third embodiment can be connected at the second and third RF ports 312 , 313 to two single-band components that cannot implement dual-band FU.

[0061] Figure 6B is a schematic diagram showing a topological structure of a dual-band filter according to a third embodiment. Figure 6B Port 1 in corresponds to Fig. 6A RF port 311, Figure 6B Port 2 in corresponds to Fig. 6A The RF port 312, and Figure 6B Port 3 in corresponds to Fig. 6A RF port 313 in.

[0062] Figures 7A-7H Different variations of dual-mode resonators according to the present disclosure are shown.

[0063] Fig. 7A The dual-mode resonator shown with Figure 1A The dual-mode resonator shown is different in that two holes are provided in the body of the two non-grounded branches. Figure 7B The dual-mode resonator shown with Figure 1A The difference of the dual-mode resonator shown is that two recesses are provided in the main body of the two non-grounded branches. Figure 1A The same as the parts or portions in FIG. 1 and the detailed description thereof will not be repeated. This applies to Figure 7C-7H Each one of them.

[0064] Figure 7C-7E The dual-mode resonator shown with Figure 1A The dual-mode resonator shown differs in that the main body of each of the two non-grounded branches is folded toward a different direction. Figure 7F The dual-mode resonator shown with Figure 1AThe difference of the dual-mode resonator shown is that the non-grounded branch on the upper side is folded at its connection. It can be understood by those skilled in the art that Figure 7C-7E The main body of the dual-mode resonator shown can be folded in opposite directions. Figure 7F The non-grounded branch at the lower middle side may also be folded at its connection portion.

[0065] Figure 7G The dual-mode resonator shown with Figure 1A The dual-mode resonator shown is different in that the main body portion of each of the two non-grounded branches does not extend toward the grounded portion side.

[0066] about Figures 7A-7G With respect to the variations shown, those skilled in the art will appreciate that increasing the area of ​​the non-grounded branch will lower the frequency of the corresponding mode, while decreasing the area of ​​the non-grounded branch can tune the frequency in an incremental direction.

[0067] Figure 7H The dual-mode resonator shown with Figure 1A The dual mode resonator shown differs in that there is an additional substantially mirrored portion of the ground relative to the connection of the two non-grounded branches. The substantially mirrored portion is provided to tune the harmonics and may have an area equal to, greater than or less than the area of ​​the ground portion.

[0068] Fig. 8A FIG. 4 shows a triple-mode resonator in a triple-band filter according to a fourth embodiment of the present disclosure. Fig. 8A As shown, the three-mode resonator is arranged in a cavity defined by a chassis, and the chassis can be made of a metal or a non-metal substrate with a metallized surface. The three-mode resonator is a microstrip line resonator, which can also be made of a metal or a non-metal substrate with a metallized surface. The material of the three-mode resonator can be the same as or different from the material of the chassis. The three-mode resonator includes three non-grounded branches 1021, 1022, 1023 and a grounding portion 1024. The grounding portion 1024 is arranged at the junction of the three non-grounded branches 1021, 1022, 1023, and is connected to the chassis by brazing or welding.

[0069] In the present embodiment, the grounding portion 1024 extends in the same plane as the three non-grounding branches 1021, 1022, and 1023. The three-mode resonator can be stamped from a metal sheet and has a uniform thickness. However, the present disclosure is not limited thereto, and the grounding portion 1024 and the three non-grounding branches 1021, 1022, and 1023 can have different thicknesses. In the present embodiment, the cross-section of the middle non-grounding branch 1022 is T-shaped, including a horizontal main body and a vertical tip. Each of the non-grounding branches 1021 and 1023 has a connecting portion connected to the grounding portion 1024 and a main body perpendicular to the connecting portion. The main body of the non-grounding branch 1021 and the main body of the non-grounding branch 1023 both extend in the horizontal direction, so as to be parallel to the main body of the non-grounding branch 1022. In this connection, it can be said that the three non-grounding branches 1021, 1022, and 1023 extend substantially parallel to each other. Preferably, the lengths of the main bodies of the three non-grounding branches 1021, 1022, 1023 in the horizontal direction are different. In addition, the widths of the main bodies of the three non-grounding branches 1021, 1022, 1023 can be the same or different from each other, and are greater than the widths of the connecting parts of the non-grounding branches 1021, 1023 and the tip of the non-grounding branch 1022.

[0070] Figure 8B The electric field (left) and magnetic field (right) of a triple-mode resonator in the first mode are shown. Figure 8C shows the electric field (left) and magnetic field (right) of a triple-mode resonator in the second mode, Fig.8D The electric field (left) and magnetic field (right) of a three-mode resonator in the third mode are shown. In this embodiment, the first mode is realized by the entire resonator, the second mode is realized by the bottom half of the resonator, and the third mode is realized by the middle part of the resonator. The frequencies and / or couplings in the three modes can be tuned at the top side, bottom side, and middle part of the resonator, respectively. For example, tuning can be performed by tuning screws or tuning plates.

[0071] Figures 9A-9D Different variations of triple-mode resonators according to the present disclosure are shown.

[0072] Fig. 9A The three-mode resonator shown is Fig. 8A The three-mode resonator shown differs in that Fig. 8A The T-shaped non-grounded branch 1022 in FIG. 1 is replaced by an L-shaped non-grounded branch.

[0073] Fig. 9B The three-mode resonator shown is Fig. 8A The three-mode resonator shown differs in that Fig. 8A The T-shaped non-grounded branch 1022 in FIG. 1 is replaced by a linear non-grounded branch without a vertical portion.

[0074] Fig. 9C The three-mode resonator shown is Fig. 9B The difference of the three-mode resonator shown is that the main body portions of the upper and lower non-grounded branches each have an additional portion extending toward the middle non-grounded branch.

[0075] Fig.9D The three-mode resonator shown is Fig. 9B The three-mode resonator shown is different in that the main bodies of the three non-grounded branches are folded along their right edges.

[0076] By reference Figures 7A-7H Other variations are contemplated. It will be appreciated by those skilled in the art that increasing the area of ​​the non-grounded branch will lower the frequency of the corresponding mode, while decreasing the area of ​​the non-grounded branch may tune the frequency in an incremental direction.

[0077] Fig. 10A FIG. 4 shows a quad-mode resonator in a quad-band filter according to a fifth embodiment of the present disclosure. Fig. 10A As shown, the quad-mode resonator is arranged in a cavity defined by a chassis, and the chassis can be made of metal or a non-metal substrate with a metallized surface. The quad-mode resonator is a microstrip line resonator, which can also be made of metal or a non-metal substrate with a metallized surface. The material of the quad-mode resonator can be the same as or different from the material of the chassis. The quad-mode resonator includes four non-grounded branches 1031, 1032, 1033, 1034 and a grounding portion 1035. The grounding portion 1035 is arranged at the junction of the four non-grounded branches 1031, 1032, 1033, 1034, and is connected to the chassis by brazing or welding.

[0078] In this embodiment, the four non-grounding branches 1031, 1032, 1033, 1034 extend in the same plane, and the grounding portion 1035 extends in a direction perpendicular to the plane. More specifically, each of the non-grounding branches 1031, 1033 has a connection portion connected to the grounding portion 1035 and a main body portion perpendicular to the connection portion, and each of the non-grounding branches 1032, 1034 has a main body portion connected to the grounding portion 1035 and a tip portion perpendicular to the main body portion. The main bodies of the non-grounding branches 1031, 1032, 1033, 1034 all extend in a horizontal direction in the plane. In this connection, it can be said that the non-grounding branches 1031, 1033 extend substantially parallel to the non-grounding branches 1032, 1034. Preferably, the main bodies of the four non-grounding branches 1031, 1032, 1033, 1034 have different lengths in the horizontal direction. The four non-grounding branches 1031, 1032, 1033, 1034 may be stamped from a metal sheet and have the same thickness. However, the present disclosure is not limited thereto, and the four non-grounding branches 1031, 1032, 1033, 1034 may have different thicknesses. In addition, the widths of the main bodies of the four non-grounding branches 1031, 1032, 1033, 1034 may be the same or different from each other, and may be greater than the widths of the connecting portions of the non-grounding branches 1031, 1033 and the tip portions of the non-grounding branches 1032, 1034.

[0079] Fig. 10B The electric field (left) and magnetic field (right) of a four-mode resonator in the first mode are shown. Fig. 10C The electric field (left) and magnetic field (right) of a quad-mode resonator in the second mode are shown. Fig. 10D The electric field (left) and magnetic field (right) of a quad-mode resonator in the third mode are shown, and Fig. 10E The electric field (left) and magnetic field (right) of a four-mode resonator in the fourth mode are shown. In this embodiment, the first mode is realized by the entire resonator (especially the top and bottom sides of the resonator), the second mode is realized by the half of the resonator near the bottom side, the third mode is realized by the left middle part of the resonator, and the fourth mode is realized by the right middle part of the resonator. The frequencies and / or couplings in the four modes can be tuned at the top side, bottom side, left middle side, and right middle side of the resonator, respectively. For example, tuning can be performed by tuning screws or tuning plates.

[0080] Fig.11A and Fig. 11B Different variations of quad-mode resonators according to the present disclosure are shown.

[0081] Fig.11A The four-mode resonator shown is Fig. 10AThe quad-mode resonator shown differs in that each of the non-grounded branches 1032', 1034' has an L-shaped cross-section. Fig. 11B The four-mode resonator shown is Fig.11A The quad-mode resonator shown is different in that each of the non-grounded branches 1031 ′, 1033 ′ has an L-shaped cross-section.

[0082] By reference Figures 7A-7H Other variations are contemplated. It will be appreciated by those skilled in the art that increasing the area of ​​the non-grounded branch will lower the frequency of the corresponding mode, while decreasing the area of ​​the non-grounded branch may tune the frequency in an incremental direction.

[0083] In the above-described embodiment, the multimode resonator is arranged in a cavity defined by a chassis. However, the present disclosure is not limited thereto. For example, Fig. 12A and Fig. 12B As shown, the multi-band filter may include a multi-layer circuit board, and the multi-mode resonator may be arranged on an intermediate layer sandwiched between an upper conductive layer and a lower conductive layer, and may be surrounded by metallized vias for electrically connecting the upper conductive layer and the lower conductive layer. The upper conductive layer, the lower conductive layer, and the metallized vias form a cavity of the multi-band filter. Each multi-mode resonator may be formed on one intermediate layer or may be formed across two or more intermediate layers, and in the latter case, portions on different layers of at least one multi-mode resonator are connected by metallized vias that pass through the layers.

[0084] In one embodiment, the middle layer is made of ceramic and the multimode resonator is formed on the middle layer by LTCC technology or HTCC technology. In another embodiment, the multilayer circuit board is a PCBA and the multimode resonator is laminated on the middle layer. In another embodiment, the multimode resonator is plated on the middle layer. In these kinds of solutions, the middle ground of the resonator can be connected to one of the metallized vias for electrically connecting the upper conductive layer and the lower conductive layer.

[0085] Although various multi-band filters and multi-mode resonators are shown and described above, technicians in the relevant field will think of other multi-band filters that include multiple multi-mode resonators, each of which is a microstrip line resonator including a ground portion and two or more non-grounded branches for realizing multiple modes.

[0086] The present disclosure also relates to a communication device, such as a radio unit or an antenna unit, comprising at least one multi-band filter as described above.The multi-band filter may be soldered on the radio board or antenna board or may be connected to the radio board or antenna board by an RF connector.

[0087] Advantages of the embodiments of the present disclosure will be described below.

[0088] According to the present disclosure, a multi-band filter includes a plurality of multi-mode resonators, each of which is a microstrip line resonator including a ground portion and two or more non-ground branches for realizing multiple modes. With this configuration, two or more modes can be easily realized in the microstrip line resonator by different areas of the resonator, thereby realizing a multi-band filter.

[0089] Compared with the existing multi-band filter that sets a common cavity to combine multiple single-band filters, the radio size / weight and cost can be reduced. In addition, the radio front-end performance, such as harmonics and insertion loss, is improved compared with the multi-band CWG filter. In addition, the multi-band filter according to the present disclosure has better reliability and robustness.

[0090] The multimode resonator may be produced separately and brazed on the chassis, or may be produced at once (ie integrally) with the chassis.

[0091] Multimode resonators can also be formed on an intermediate layer of a multilayer circuit board, for example by LTCC or HTCC technology, by lamination on a PCB or by plating on ceramic.

[0092] The frequencies and / or couplings in the different modes can be tuned separately during production, for example, by means of tuning screws or tuning disks.

[0093] To obtain better out-of-band attenuation, a metal microstrip line LPF can be added in the input region or output region of the multi-band filter.

[0094] To further reduce the filter size, plastic material may be added on at least one side of the microstrip line resonator.

[0095] The multi-band filter can have multiple RF ports and can be coupled with a single-mode resonator according to different requirements, which is flexible.

[0096] The multi-band filter according to the present disclosure can be soldered on a PCB, such as a radio board or antenna board, or can be connected to other radio components through an RF connector. This provides a flexible assembly solution for the filter, as well as an advanced manufacturing practice solution.

[0097] References in this disclosure to "an embodiment," "another embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is considered to be within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0098] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more associated listed terms.

[0099] The terms used herein are only used to describe the purpose of specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "one", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "include", "include", "have", "have", "include" and / or "include", when used in this article, specify the presence of the features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or their combinations. The terms "connect", "connect", "connect" and / or "connected" used herein cover the direct and / or indirect connection between two elements.

[0100] The present disclosure includes any novel feature or combination of features explicitly disclosed herein or any summary thereof. When read in conjunction with the accompanying drawings, various modifications and adaptations to the aforementioned exemplary embodiments of the present disclosure may become apparent to those skilled in the relevant art in view of the foregoing description. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of the present disclosure.

Claims

1. A multi-band filter comprising a plurality of multi-mode resonators, wherein each of the multi-mode resonators is a microstrip line resonator, the microstrip line resonator comprising a ground portion and two or more non-ground branches for realizing a plurality of modes.

2. The multi-band filter according to claim 1, further comprising: A chassis defines a cavity, wherein the multi-mode resonator is arranged in the cavity, and the ground portion is connected to the chassis.

3. The multi-band filter according to claim 2, wherein: The multi-mode resonator is manufactured integrally with the chassis.

4. The multi-band filter according to claim 2, wherein: The multi-mode resonator is manufactured separately from the chassis and is connected to the chassis by brazing or welding.

5. The multi-band filter according to any one of claims 2 to 4, wherein: The chassis and / or the microstrip line resonator are made of metal or a non-metal substrate with a metallized surface.

6. The multi-band filter according to claim 1, further comprising a multi-layer circuit board, wherein: The multi-mode resonator is arranged on an intermediate layer, the intermediate layer is sandwiched between an upper conductive layer and a lower conductive layer, and is surrounded by metallized vias for electrically connecting the upper conductive layer and the lower conductive layer.

7. The multi-band filter according to claim 6, wherein: A ground portion of each of the multi-mode resonators is connected to one of the metallized vias.

8. The multi-band filter according to claim 6 or 7, wherein: The intermediate layer is made of ceramic, and the multi-mode resonator is formed on the intermediate layer by LTCC (Low Temperature Co-fired Ceramic) technology or HTCC (High Temperature Co-fired Ceramic) technology.

9. The multi-band filter according to claim 6 or 7, wherein: The multi-layer circuit board is a PCBA (Printed Circuit Board Assembly), and the multi-mode resonator is laminated on the intermediate layer.

10. The multi-band filter according to any one of claims 6 to 9, wherein: At least one multi-mode resonator is formed across two or more intermediate layers, and portions of the at least one multi-mode resonator on different layers are connected by metallized vias passing through the two or more layers.

11. The multi-band filter according to any one of claims 1 to 10, wherein: A first multimode resonator of the plurality of multimode resonators is connected to a first RF (radio frequency) port, and a second multimode resonator of the plurality of multimode resonators is connected to a second RF port.

12. The multi-band filter according to any one of claims 1 to 10, wherein: A first multimode resonator of the plurality of multimode resonators is connected to a first RF (radio frequency) port, and a second multimode resonator of the plurality of multimode resonators is coupled to a plurality of single-mode resonators, each of which is connected to a corresponding one of a plurality of second RF ports.

13. The multi-band filter according to any one of claims 1 to 12, wherein: The multi-band filter can be tuned during production by means of tuning screws or tuning plates.

14. The multi-band filter according to claim 13, wherein: The frequency and / or the coupling in different modes may be tuned separately.

15. The multi-band filter according to any one of claims 1 to 14, wherein: The non-grounded branches of the microstrip line resonator extend substantially in the same plane.

16. The multi-band filter according to claim 15, wherein: At least one of the non-grounded branches can be folded and / or can be provided with an enlarged end.

17. The multi-band filter according to claim 15, wherein: At least one of the non-ground branches may be formed with a hole or a recess.

18. The multi-band filter according to any one of claims 15 to 17, wherein: The at least two non-grounded branches of the microstrip line resonator extend substantially parallel to each other and have different lengths in the extending direction.

19. The multi-band filter according to any one of claims 1 to 18, wherein: The grounding portion of the microstrip line resonator is disposed at a junction of the two or more non-grounding branches.

20. The multi-band filter according to any one of claims 1 to 19, wherein: Plastic material is added to at least one side of the microstrip line resonator.

21. The multi-band filter according to any one of claims 1 to 20, wherein: A metal microstrip line LPF (low pass filter) is provided at an input region or an output region of the multi-band filter.

22. A communication device comprising at least one multi-band filter according to any one of claims 1 to 21.

23. The communication device according to claim 22, wherein: The multi-band filter is soldered on the radio board or the antenna board, or connected to the radio board or the antenna board through an RF connector.

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