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(11) | EP 3 280 000 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
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| (54) | DIELECTRIC FILTER |
| (57) The present invention provides a dielectric filter, including a cavity, a resonant
cavity, a cover plate, and a connecting rib. The cavity includes an accommodating
cavity and a cavity wall surrounding the accommodating cavity. A resonator is disposed
inside the accommodating cavity, the resonator includes a support medium and a main
medium, the support medium is disposed on a bottom wall of the accommodating cavity,
and the main medium is disposed on the support medium. The cover plate covers the
cavity to close the accommodating cavity. The connecting rib is accommodated in the
accommodating cavity, and is disposed on a radiation plane formed between a radiation
radiated from a center axis of the resonator onto the cavity wall and the center axis
of the resonator, where a shortest distance between the connecting rib and the main
medium is greater than a preset value. The present invention achieves an object of
pushing away a high-order harmonic wave. The present invention further provides a
dielectric filter component and a base station. |
TECHNICAL FIELD
[0001] The present invention relates to the field of communications technologies, and in particular, to a dielectric filter.
BACKGROUND
[0002] Due to the development of radio communications technologies, a high-performance filter is required in a low-cost and high-performance wireless communications transceiver system. A dielectric filter is widely applied to various communications systems gradually because of its small size, low loss, and high selectivity. The dielectric filter is designed by using a dielectric material (for example, ceramic) that is characterized by a low loss, a high dielectric constant, a small frequency temperature coefficient, a small coefficient of thermal expansion, high bearable power, and the like. Generally, the dielectric filter may be formed by several long-type resonators arranged in multi-level series or parallel longitudinally along a trapezoidal line. Such dielectric filter is characterized by a low insertion loss, a high power capacity, and narrow bandwidth, and is especially suitable for filtering at 900 MHz, 1.8 GHz, 2.4 GHz, and 5.8 GHz, and therefore can be applied to level coupling filtering of a portable phone, a car phone, a wireless headset, a wireless microphone, a radio station, a cordless telephone, an integrated transceiver duplexer, or the like. The dielectric filter includes a cavity, a dielectric resonator fastened in the cavity, a cover plate, and a tuning screw. A TEoi mode dielectric filter is a type of dielectric filter, and has a good single-cavity Q value characteristic. Therefore, the TEoi mode dielectric filter is widely applied to a wireless communications system, to reduce a system loss and improve efficiency. However, the TE01 mode dielectric filter also has the following disadvantages: Because a frequency of a high-order harmonic wave of the TEoi mode dielectric filter is close to a TEoi mode frequency, it is difficult for the TEoi mode dielectric filter to suppress the high-order harmonic wave.
SUMMARY
[0003] The technical problem to be resolved by embodiments of the present invention is to provide a dielectric resonator, to push away a high-order harmonic wave in a dielectric filter, so as to suppress the high-order harmonic wave.
[0004] According to a first aspect, a dielectric filter is provided, including:
a cavity, where the cavity includes an accommodating cavity and a cavity wall surrounding the accommodating cavity;
a resonator, where the resonator is disposed inside the accommodating cavity, the resonator includes a support medium and a main medium, the support medium is disposed on a bottom wall of the accommodating cavity, and the main medium is disposed on the support medium;
a cover plate, where the cover plate covers the cavity to close the accommodating cavity; and
a connecting rib, where the connecting rib is accommodated in the accommodating cavity, and is disposed on a radiation plane formed between a radiation radiated from a center axis of the resonator onto the cavity wall and the center axis of the resonator, where a shortest distance between the connecting rib and the main medium is greater than a preset value.
[0005] In a first possible implementation manner of the first aspect, the connecting rib is disposed on at least one of the bottom wall of the accommodating cavity, the cover plate, or the cavity wall of the accommodating cavity.
[0006] With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner, the dielectric filter further includes a tuning member, the tuning member is disposed on the cover plate, and a center axis of the tuning member is the same as a center axis of the cover plate; when the connecting rib is disposed on at least one of the bottom wall of the accommodating cavity or the cavity wall of the accommodating cavity, the connecting rib is connected to the support medium and the cavity wall of the accommodating cavity; and when the connecting rib is disposed on the cover plate, the connecting rib is connected to the tuning member and the cavity wall of the accommodating cavity.
[0007] With reference to the first or the second possible implementation manner of the first aspect, in a third possible implementation manner, the radiation plane forms a first projection on the bottom wall; when the connecting rib is disposed on the bottom wall of the accommodating cavity, the connecting rib forms a second projection on the bottom wall, and the second projection overlaps with the first projection on a center line in a direction from the resonator to the cavity wall; when the connecting rib is disposed on the cavity wall, the connecting rib forms a third projection on the bottom wall, and the third projection overlaps with the first projection on a center line in a direction from the resonator to the cavity wall; and when the connecting rib is disposed on the cover plate, the connecting rib forms a fourth projection on the cover plate, and the fourth projection overlaps with the first projection on a center line in a direction from the center axis of the cover plate to the cavity wall.
[0008] With reference to any one of the first to the third possible implementation manners of the first aspect, in a fourth possible implementation manner, when the connecting rib is disposed on the bottom wall of the accommodating cavity, the connecting rib is integrated with the bottom wall; when the connecting rib is disposed on the cavity wall of the accommodating cavity, the connecting rib is integrated with the cavity wall; and when the connecting rib is disposed on the cover plate, the connecting rib is integrated with the cover plate.
[0009] In a fifth possible implementation manner of the first aspect, or with reference to any one of the first to the fourth possible implementation manners of the first aspect, in a fifth possible implementation manner, the connecting rib includes a support part and a first extending part that is formed by extending a first end of the support part in a direction away from the support part, and shortest distances between the support part and the main medium and between the first extending part and the main medium are greater than the preset value.
[0010] With reference to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the connecting rib further includes a second extending part, the second extending part is formed by extending, in a direction away from the support part, a second end that is of the support part and that is opposite to the first end, where a shortest distance between the second extending part and the main medium is greater than the preset value.
[0011] In a seventh possible implementation manner of the first aspect, or with reference to any one of the first to the sixth possible implementation manners of the first aspect, in a seventh possible implementation manner, there are at least two connecting ribs; and with the center axis of the resonator as a center line, the at least two connecting ribs are evenly arranged around the center line.
[0012] With reference to any one of the first to the seventh possible implementation manners of the first aspect, in an eighth possible implementation manner, when connecting ribs are disposed on any two of the bottom wall, the cavity wall, and the cover plate, the connecting ribs disposed on the any two of the bottom wall, the cavity wall, and the cover plate are not in contact with each other; or when connecting ribs are disposed on all the bottom wall, the cavity wall, and the cover plate, the connecting ribs disposed on the bottom wall, the cavity wall, and the cover plate are not in contact with each other.
[0013] In a ninth possible implementation manner of the first aspect, or with reference to any one of the first to the eighth possible implementation manners of the first aspect, in a ninth possible implementation manner, the preset value is 2 mm.
[0014] According to a second aspect, a dielectric filter component is provided, including a low-pass filter and the dielectric resonator according to the foregoing possible implementation manners of the first aspect, where the low-pass filter is cascaded with the dielectric filter.
[0015] According to a third aspect, a base station is provided, including the dielectric filter component according to the second aspect.
[0016] In the present invention, the dielectric filter includes a cavity, a resonant cavity, a cover plate, and a connecting rib. The cavity includes an accommodating cavity and a cavity wall surrounding the accommodating cavity. The resonator is disposed inside the accommodating cavity, the resonator includes a support medium and a main medium, the support medium is disposed on a bottom wall of the accommodating cavity, and the main medium is disposed on the support medium. The cover plate covers the cavity to close the accommodating cavity. The connecting rib is accommodated in the accommodating cavity, and is disposed on a radiation plane formed between a radiation radiated from a center axis of the resonator onto the cavity wall and the center axis of the resonator, where a shortest distance between the connecting rib and the main medium is greater than a preset value. Because the connecting rib is disposed on the radiation plane formed between the radiation radiated from the center axis of the resonator onto the cavity wall and the center axis I of the resonator, and the connecting rib is orthogonal to a magnetic field of a high-order harmonic wave of the dielectric filter, the connecting rib affects a path of the magnetic field, resulting in a change in a frequency of the high-order harmonic wave. Further, because the connecting rib is disposed inside the accommodating cavity, a volume of air in the accommodating cavity becomes smaller, so that the frequency of the high-order harmonic wave becomes higher. This implements a function of pushing away the high-order harmonic wave. The dielectric filter in the present invention also maintains performance of a TEoi mode when pushing away the high-order harmonic wave for suppression.
BRIEF DESCRIPTION OF DRAWINGS
[0017] To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.
FIG. 1 is a schematic exploded view of a part of a dielectric filter according to a first embodiment of the present invention;
FIG. 2 is a longitudinal sectional view of FIG. 1;
FIG. 3 is a diagram of electric field distribution of a TE01 mode of a TEoi mode dielectric filter on which no connecting rib is disposed;
FIG. 4 is a diagram of magnetic field distribution of a TE01 mode of a TE01 mode dielectric filter on which no connecting rib is disposed;
FIG. 5 is a diagram of electric field distribution of a high-order harmonic wave of a TE01 mode dielectric filter on which no connecting rib is disposed;
FIG. 6 is a diagram of magnetic field distribution of a TE01 mode of a TE01 mode dielectric filter on which no connecting rib is disposed;
FIG. 7 is a top view of a cavity in FIG. 1;
FIG. 8 is a longitudinal sectional view of another dielectric filter according to a first embodiment of the present invention;
FIG. 9 is a longitudinal sectional view of still another dielectric filter according to a first embodiment of the present invention;
FIG. 10 is a block diagram of a dielectric filter component according to a second embodiment of the present invention; and
FIG. 11 is a block diagram of a base station according to a third embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0018] The following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely some but not all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0019] In the specification, claims, and accompanying drawings of the present invention, the terms "first", "second", "third", "fourth", and so on (if existent) are intended to distinguish between similar objects but do not necessarily indicate a specific order or sequence. It should be understood that the data termed in such a way are interchangeable in proper circumstances so that the embodiments of the present invention described herein can be implemented in orders except the order illustrated or described herein. Moreover, the terms "include", "contain" and any other variants mean to cover the non-exclusive inclusion, for example, a process, method, system, product, or device that includes a list of steps or units is not necessarily limited to those units, but may include other units not expressly listed or inherent to such a process, method, system, product, or device.
[0021] Referring to FIG. 1, FIG. 1 shows a dielectric filter 100 according to a first embodiment of the present invention. The dielectric filter includes a cavity 10, a resonator 20, a cover plate 30, and a connecting rib 50. The cavity 10 includes an accommodating cavity 11 and a cavity wall 12 surrounding the accommodating cavity 11. The resonator 20 is disposed inside the accommodating cavity 11. The resonator 20 includes a support medium 22 and a main medium 23. The support medium 22 is disposed on a bottom wall 112 of the accommodating cavity 11. The main medium 23 is disposed on the support medium 22. The cover plate 30 covers the cavity 10 to close the accommodating cavity 11. The connecting rib 50 is accommodated in the accommodating cavity 11, and is disposed on a radiation plane formed between a radiation radiated from a center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20. A shortest distance between the connecting rib 50 and the main medium 23 is greater than a preset value.
[0022] The dielectric filter 100 may be a single-cavity dielectric filter. Generally, the cavity wall 12 and the cover plate 30 may be made of a metal material, or a material having a metal-plated surface. In another embodiment, the dielectric filter 100 may also be a multi-cavity dielectric filter. The multi-cavity dielectric filter includes multiple single-cavity dielectric filters.
[0023] It should be noted that, that the shortest distance between the connecting rib 50 and the main medium 23 is greater than the preset value means that a distance from any part of the connecting rib 50 to any location of the main medium 23 is greater than the preset value.
[0024] In this embodiment, the connecting rib 50 may be disposed on the bottom wall 112. The preset value may be 2 mm. The dielectric filter 100 may be a TEoi mode dielectric filter. The TEoi mode dielectric filter is a filter whose single cavity includes a TEoi mode resonator. A TE mode in field distribution of a waveguide is that: An electric field is fully distributed in a cross section perpendicular to a propagation direction of an electromagnetic wave and a magnetic field has a waveform with a component in a propagation direction. TEoi is the first TE waveform in such type of waveguide. The connecting rib 50 may be made of a conductive material, for example, a metal material such as aluminum. In another embodiment, the preset value may be adjusted according to an actual suppression degree requirement of a filter.
[0025] Optionally, the dielectric filter 100 may further include a tuning member 40, configured to perform fine-tuning on a working frequency of the filter. The tuning member 40 may be disposed on the cover plate 30, or may be disposed in another manner, such as being fastened to the main medium 23 or being fastened by using pressure between the main medium 23 and the cover plate 30. A specific manner may not be limited in this embodiment of the present invention. For example, the tuning member 40 is disposed on the cover plate 30. The main medium 23, the support medium 22, and the tuning member 40 are disposed coaxially. A diameter of the main medium 23 is greater than a diameter of the support medium 22. The main medium 23 and the support medium 22 are made of different materials. The materials of the main medium 23 and the support medium 22 may be materials, such as ceramic and titanate, that have properties such as a high dielectric constant, a low loss, and a stable temperature coefficient. Specifically, a dielectric constant of the main medium 23 is large, and a dielectric constant of the support medium 22 is small. In this way, most of electromagnetic waves can be trapped inside the main medium 23, and therefore a dielectric loss is small.
[0026] In another embodiment, the connecting rib 50 may also be disposed on the cover plate 30 or the cavity wall 12. Certainly, connecting ribs 50 may be separately disposed on any two of the bottom wall 112, the cover plate 30, and the cavity wall 12, or connecting ribs 50 may be separately disposed on the bottom wall 112, the cover plate 30, and the cavity wall 12.
[0027] It should be noted that, when connecting ribs 50 are separately disposed on any two of the bottom wall 112, the cavity wall 12, and the cover plate 30, or connecting ribs 50 are separately disposed on the bottom wall 112, the cavity wall 12, and the cover plate 30, the connecting ribs 50 disposed on the any two of the bottom wall 112, the cavity wall 12, and the cover plate 30 are not in contact with each other, or the connecting ribs 50 disposed on the bottom wall 112, the cavity wall 12, and the cover plate 30 are not in contact with each other, so as to prevent structural interference from affecting performance of the filter.
[0028] Optionally, the center axis I of the resonator 20 may be the same as a center axis I of the cover plate 30.
[0029] Optionally, a center axis I of the tuning member 40 may be the same as the center axis I of the cover plate 30.
[0030] It should be noted that the connecting rib 50 is disposed on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20, so that the connecting rib 50 may be perpendicular to a magnetic field of a high-order harmonic wave, so as to affect a path of the magnetic field of the high-order harmonic wave, thereby changing a frequency of the high-order harmonic wave.
[0031] A TEoi mode dielectric filter has a characteristic that a frequency of a high-order harmonic wave is close to a TE01 mode frequency. Referring to FIG. 3 to FIG. 6, FIG. 3 is a diagram of electric field distribution of a TEoi mode of a TEoi mode dielectric filter on which no connecting rib is disposed. FIG. 4 is a diagram of magnetic field distribution of a TEoi mode of a TEoi mode dielectric filter on which no connecting rib is disposed. FIG. 5 is a diagram of electric field distribution of a high-order harmonic wave of a TEoi mode dielectric filter on which no connecting rib is disposed. FIG. 6 is a diagram of magnetic field distribution of a TEoi mode of a TEoi mode dielectric filter on which no connecting rib is disposed.
For the TE01 mode:
[0032] In FIG. 3, an electric field of the TEoi mode is mainly concentrated at a main medium. In this embodiment of the present invention, the connecting rib 50 is accommodated in the accommodating cavity 11, and a shortest distance between the connecting rib 50 and the main medium 23 is greater than the preset value. Impact of the connecting rib 50 on the electric field is very small, and can be ignored.
[0033] In FIG. 4, a magnetic field of the TEoi mode is of a turbine shape. The connecting rib 50 is accommodated in the accommodating cavity 11, and is disposed on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20, that is, the connecting rib 50 is in a tangent line direction of the magnetic field. Therefore, the connecting rib 50 almost does not affect the magnetic field.
[0034] Therefore, it may be learnt by means of analysis that the connecting rib 50 almost does not affect the TE01 mode, and therefore a frequency and a Q value of the TE01 mode of the dielectric filter 100 is almost unchanged. In this way, performance of the TEoi mode is maintained. The performance of the TE01 mode is reflected by the frequency and the Q value of the TEoi mode. The Q value of the TEoi mode is a ratio of stored energy to lost energy in a resonant period.
For a high-order harmonic wave:
[0035] In FIG. 5, a part of an electric field of the high-order harmonic wave is upwards perpendicular to a peripheral wall of the main medium 23, and the other parts of the electric field of the high-order harmonic wave are substantially perpendicular to a top surface and a bottom surface of the main medium 23. A direction of the part of the electric field that is of the high-order harmonic wave and that is perpendicular to the main medium 23 is parallel to an arrangement direction of the connecting rib 50; and the part that is of the electric field and that is perpendicular to the top surface and the bottom surface of the main medium 23 is parallel to a side surface of the connecting rib 50. Therefore, impact of the connecting rib 50 on the electric field of the high-order harmonic wave is very small, and can be ignored.
[0036] In FIG. 6, a magnetic field of the high-order harmonic wave is distributed surrounding the main medium, the support medium, a mounting table, and the tuning member. The connecting rib 50 is disposed on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20, that is, the connecting rib 50 is orthogonal to the magnetic field. Therefore, the connecting rib 50 affects a path of the magnetic field, resulting in a change in a frequency of the high-order harmonic wave. Further, because the connecting rib 50 is disposed inside the accommodating cavity 11, a volume of air in the accommodating cavity 11 becomes smaller, so that the frequency of the high-order harmonic wave becomes higher. Therefore, a function of pushing away the high-order harmonic wave is implemented.
[0037] Therefore, according to the foregoing analysis, in this embodiment, the dielectric filter 100 includes the connecting rib 50. The connecting rib 50 is accommodated in the accommodating cavity 11, and is disposed on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20. A shortest distance between the connecting rib 50 and the main medium 23 is greater than a preset value. Because the connecting rib 50 is disposed on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20, and the connecting rib 50 is orthogonal to the magnetic field of the high-order harmonic wave of the dielectric filter 100, the connecting rib 50 affects a path of the magnetic field, resulting in a change in a frequency of the high-order harmonic wave. Further, because the connecting rib 50 is disposed inside the accommodating cavity 11, a volume of air in the accommodating cavity 11 becomes smaller, so that a frequency of the high-order harmonic wave becomes higher. Therefore, a function of pushing away the high-order harmonic wave is implemented. The dielectric filter 100 in the present invention also maintains performance of a TEoi mode when pushing away the high-order harmonic wave for suppression.
[0038] It should be noted that a push-away effect of the connecting rib 50 on the high-order harmonic wave depends on a volume that is of the accommodating cavity 11 and that is occupied by the connecting rib 50, regardless of a location that is on the accommodating cavity 11 and at which the connecting rib 50 is disposed. A larger volume that is of the accommodating cavity 11 and that is occupied by the connecting rib 50 indicates a smaller volume of air in the accommodating cavity 11, resulting in a higher frequency of the high-order harmonic wave. Therefore, the push-away effect on the high-order harmonic wave is better.
[0039] Optionally, the resonant cavity 20 may further include a mounting table 21. The mounting table 21 is disposed on the bottom wall 112 of the accommodating cavity 11. The support medium 22 is disposed on the bottom wall 112 of the accommodating cavity 11 by using the mounting table 21. The mounting table 21 may be made of a metal material such as aluminum. It has been experimentally found that an effect of the solution provided in this embodiment of the present invention is better when the resonator 20 is fastened by using the mounting table 21. However, it may be understood that, for a specific manner for fastening a resonant cavity, refer to some existing manners or some manners emerging in the future. This does not affect application of the present invention, and details are not described herein.
[0040] In another embodiment, the connecting rib 50 may also not be limited to being disposed only on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20. Provided that the connecting rib 50 is disposed in a tangent line direction of a magnetic field of a TEoi mode, the connecting rib 50 is orthogonal to a magnetic field of a high-order harmonic wave of the dielectric filter 100. This affects a path of the magnetic field of the high-order harmonic wave, resulting in a change in a frequency of the high-order harmonic wave, thereby achieving a same effect on pushing away the high-order harmonic wave.
[0041] In addition, provided that the connecting rib 50 is not disposed in parallel to the magnetic field of the high-order harmonic wave, the connecting rib 50 affects the path of the magnetic field of the high-order harmonic wave, and the frequency of the high-order harmonic wave can be changed, just bringing less impact on the path of the magnetic field of the high-order harmonic wave and changing the frequency of the high-order harmonic wave in comparison with impact caused due to that the connecting rib 50 is orthogonal to the magnetic field of the high-order harmonic wave. Therefore, when the connecting rib 50 is disposed on the radiation plane formed between the radiation radiated from the center axis I of the resonator 20 onto the cavity wall 12 and the center axis I of the resonator 20, the connecting rib 50 can push away the high-order harmonic wave to a greatest extent. Optionally, the connecting rib 50 may connect the support medium 22 and the cavity wall 12. When the resonant cavity 20 further includes the mounting table 21 and the support medium 22 is disposed on the bottom wall 112 of the accommodating cavity 11 by using the mounting table 21, the connecting rib 50 may connect the mounting table 21 and the cavity wall 12.
[0042] In another embodiment, when the connecting rib 50 is disposed on the cover plate 30, the connecting rib 50 may connect the tuning member 40 and the cavity wall 12. When the connecting rib 50 is disposed on the cavity wall 12, the connecting rib 50 may connect the support medium 22 and the cavity wall 12.
[0043] It should be noted that when the connecting rib 50 connects the mounting table 21 (or the support medium 22) and the cavity wall 12, or in another embodiment, when the connecting rib 50 connects the tuning member 40 and the cavity wall 12, the connecting rib 50 has a longest length. When a height of the connecting rib 50 is constant, the connecting rib 50 has a longest length. Therefore, an area that is of the connecting rib 50 and that is perpendicular to the magnetic field of the high-order harmonic wave is largest, and greatest impact on the magnetic field of the high-order harmonic wave is caused. Therefore, a best effect of pushing away the high-order harmonic wave is achieved.
[0044] Optionally, when the connecting rib 50 is disposed on the bottom wall 112, the connecting rib 50 may be integrated with the bottom wall 112. When the connecting rib 50 is disposed on the cavity wall 12, the connecting rib 50 may be integrated with the cavity wall 12. When the connecting rib 50 is disposed on the cover plate 30, the connecting rib 50 may be integrated with the cover plate30. Therefore, when the connecting rib 50 is disposed on at least one of the bottom wall 112 or the cavity wall 12, the connecting rib 50 may be formed by performing die casting on the cavity 10; and when the connecting rib 50 is disposed on the cover plate 30, the connecting rib 50 may be formed by performing die casting on the cover plate 30, without additional costs.
[0045] Referring to FIG. 7, optionally, there are at least two connecting ribs 50. With the center axis I of the resonator 20 as a center line, the at least two connecting ribs 50 are evenly arranged surrounding the center line. The radiation plane forms a first projection on the bottom wall. Specifically, in this embodiment, there are four connecting ribs 50. The connecting ribs 50 are symmetrically arranged on the bottom wall 112 in a cross manner. The connecting rib 50 is of a cuboid shape. A cross section of the connecting rib 50 is rectangular. A longitudinal section of the connecting rib 50 is rectangular. The connecting rib 50 forms a second projection on the bottom wall 112. The second projection overlaps with the first projection on a center line in a direction from the resonator 20 to the cavity wall 12. Therefore, the connecting rib 50 is orthogonal to the magnetic field of the high-order harmonic wave. This more effectively changes a path of the magnetic field, and better improves a frequency of the high-order harmonic wave.
[0046] It should be noted that the connecting rib 50 may also be of another shape, such as an L shape, and the cross section and the longitudinal section of the connecting rib 50 may also be of other shapes. The shape of the connecting rib 50, shapes of the cross section and the longitudinal section thereof, and whether the connecting rib 50 is of a symmetrical structure do not affect a push-away effect on the high-order harmonic wave in the present invention. This is not limited herein.
[0047] In another embodiment, when the connecting rib 50 is disposed on the cavity wall 12, the connecting rib 50 forms a third projection on the bottom wall 112. The third projection overlaps with the first projection on a center line in a direction from the resonator 20 to the cavity wall 12. When the connecting rib 50 is disposed on the cover plate 30, the connecting rib 50 forms a fourth projection on the cover plate 30. The fourth projection overlaps with the first projection on a center line in a direction from a center axis of the cover plate 30 to the cavity wall 12.
[0048] It should be noted that each connecting rib 50 is independent, and shapes of multiple connecting ribs 50 may also not be exactly the same. In this embodiment, shapes of the connecting ribs 50 are the same.
[0049] For a quantity of the connecting ribs: A larger quantity of the connecting ribs 50 indicates a smaller volume of air in the accommodating cavity 11 and a higher frequency of the high-order harmonic wave. Therefore, the connecting ribs 50 have a better push-away effect on the high-order harmonic wave.
[0050] Impact of the quantity of the connecting ribs 50 on the push-away effect of the high-order harmonic wave is illustrated herein by using an example. The connecting rib 50 is a square with a height set to 8 mm. When quantities of the connecting ribs 50 are 1, 2, and 4 respectively, it has been experimentally obtained that frequencies of the high-order harmonic wave are pushed up by 70 MHz, 170 MHz, and 310 MHz respectively by using one connecting rib 50, two connecting ribs 50, and four connecting ribs 50.
[0051] Referring to FIG. 8, FIG. 8 shows another dielectric filter 200 according to the first embodiment of the present invention. The dielectric filter 200 provided in the second embodiment is similar to the dielectric filter 100 provided in the first embodiment. A difference between the two dielectric filters lies in that: In the second embodiment, a connecting rib 210 is approximately of an "L" shape. The connecting rib 210 includes a support part 211 and a first extending part 212 that is formed by extending from a first end of the support part 211 in a direction away from the support part. Shortest distances between the support part 211 and the main medium 23 and between the first extending part 212 and the main medium 23 are greater than a preset value.
[0052] In this embodiment, the first end of the support part 211 is an end far away from the resonator 20. There may be at least two connecting ribs 210, and the connecting ribs 210 all are of an "L" shape. In another embodiment, the first end of the support part 211 may also be an end close to the resonator 20.
[0053] When the connecting rib 210 is disposed on the bottom wall 112, a height of the first extending part 212 may be adjusted according to actual needs. The height of the first extending part 212 may reach a top part of the cavity 10, provided that the first extending part 212 does not touch the cover plate 30, and the shortest distance between the first extending part 212 and the main medium 23 is greater than the preset value. When the connecting rib 210 is disposed on the cover plate, the height of the first extending part 210 may be adjusted according to actual needs, provided that the first extending part 212 does not touch the bottom wall 112, and the shortest distance between the first extending part 212 and the main medium 23 is greater than the preset value.
[0054] Certainly, a higher height of the first extending part 212 indicates a larger volume of the connecting rib 210, and therefore a larger volume of the accommodating cavity is occupied, resulting in a smaller volume of air in the accommodating cavity and a higher frequency of the high-order harmonic wave. This has a better push-away effect on the high-order harmonic wave.
[0055] In addition, in another embodiment, the shortest distance between the support part 211 and the main medium 23 may be greater than a first preset value, and the shortest distance between the first extending part 212 and the main medium 23 may be greater than a second preset value. The first preset value is different from the second preset value. Compared with the support part 211, the first extending part 212 has greater impact on a magnetic field in which the main medium 23 is located. Therefore, the second preset value may be set to be greater than the first preset value.
[0056] It should be noted that farther distances between the first extending part 212 and the main medium 23 and between the support part 211 and the main medium 23 indicate that less impact is caused on the magnetic field in which the main medium 23 is located.
[0057] Referring to FIG. 9, FIG. 9 shows a dielectric filter 300 according to a third embodiment of the present invention. The dielectric filter 300 provided in the third embodiment is similar to the dielectric filter 200 provided in the second embodiment. A difference between the two dielectric filters lies in that: In the third embodiment, the connecting rib 310 further includes a second extending part 312. The second extending part 312 is formed by extending, in a direction away from the support part 211, a second end that is of the support part 211 and that is opposite to the first end. A shortest distance between the second extending part 312 and the main medium 23 is greater than the preset value.
[0058] In this embodiment, there are at least two connecting ribs 210, and all the connecting ribs 210 are of a concave shape.
[0059] When the connecting rib 310 is disposed on a bottom wall 112 or a cavity wall 12, a height of the second extending part 312 may be adjusted according to actual needs, provided that the second extending part 312 does not touch the cover plate 30, and the shortest distance between the second extending part 312 and the main medium 23 is greater than the preset value. When the connecting rib 310 is disposed on the cover plate 30, the height of the second extending part 310 may be adjusted according to actual needs, provided that the second extending part 312 does not touch the bottom wall 112, and the shortest distance between the second extending part 312 and the main medium 23 is greater than the preset value.
[0060] Certainly, a higher height of the second extending part 312 indicates a larger volume of the connecting rib 310, and therefore a larger volume of the accommodating cavity 12 is occupied, resulting in a smaller volume of air in the accommodating cavity 12 and a higher frequency of the high-order harmonic wave. This has a better push-away effect on the high-order harmonic wave.
[0061] Impact of the shape of the connecting rib 310 on the push-away effect of the high-order harmonic wave is illustrated herein by using an example. A height of the support part 211 is 8 mm. The first extending part 212 has a same height as that of a top part of the cavity wall 12. The second extending part 312 is a square of 5*5. It has been experimentally obtained that a frequency of the high-order harmonic wave is pushed up to 370 MHz from 310 MHz at which there is no second extending part 312.
[0062] Impact of the height of the connecting rib 310 on the push-away effect of the high-order harmonic wave is illustrated herein by using an example. There are four connecting ribs 310, and the four connecting ribs 310 are rectangular and symmetrically arranged on the bottom wall 112 in a cross manner. Heights of the connecting rib 310 are set to 2 mm, 4 mm, and 8 mm respectively. It has been experimentally obtained that frequencies of the high-order harmonic wave are pushed up to 50 MHz, 130 MHz, and 310 MHz respectively by using the connecting ribs 310 with heights of 2 mm, 4 mm, and 8 mm.
[0063] In addition, in another embodiment, a shortest distance between the support part 211 and the main medium 23 may be greater than a first preset value, and a shortest distance between the first extending part 212 and the main medium is greater than a second preset value. The shortest distance between the second extending part 312 and the main medium 23 is greater than a third value. The first preset value may be different from the second preset value and the third preset value. The second preset value may also be different from the third preset value. Compared with the support part 211, the first extending part 212 has greater impact on a magnetic field in which the main medium 23 is located. Compared with the support part 211, the second extending part 312 has greater impact on the magnetic field in which the main medium 23 is located. Therefore, both the second preset value and the third preset value may be set to be greater than the first preset value.
[0064] It should be noted that farther distances between the first extending part 212 and the main medium 23, between the second extending part 312 and the main medium 23, and between the support part 211 and the main medium 23 indicate less impact on the magnetic field in which the main medium 23 is located.
[0065] It may be understood that a dielectric filter may also include any dielectric filter in one or more of the foregoing embodiments. For example, when more than one dielectric filters are combined, cavity walls thereof may be connected, and cover plates thereof may also be connected. For a combination manner, refer to an existing manner or a manner emerging in the future, and details are not described herein.
[0066] Referring to FIG. 10, FIG. 10 shows a dielectric filter component 1000 according to a second embodiment of the present invention. The dielectric filter component 1000 includes a low-pass filter 1100 and a dielectric filter. The low-pass filter 1100 is cascaded with the dielectric filter, to achieve better filter performance.
[0067] Because a connecting rib 50 pushes away a high-order harmonic wave of a TE01 mode, a frequency of the high-order harmonic wave of the TE01 mode is increased. The low-pass filter 1100 is cascaded with the dielectric filter, to provide suppression on the high-order harmonic wave of the TEoi mode, so that a better filtering effect is achieved after the dielectric filter is cascaded with the low-pass filter 1100.
[0068] Optionally, in order to reduce insertion loss impact of the low-pass filter 1100 on an overall filter obtained after cascading, in actual application, a cut-off frequency of the low-pass filter needs to keep a specific spacing from a passband frequency of the dielectric filter. For example, the passband frequency of the dielectric filter is 2620 MHz to 2690 MHz, and the cut-off frequency of the low-pass filter 1100 is generally required to be higher than 3200 MHz. Therefore, the low-pass filter 1100 can provide suppression on only a high-order harmonic wave that is generated in the dielectric filter and whose frequency is higher than 3200 MHz. If the connecting rib 50 pushes away, a frequency of a high-order harmonic wave whose frequency is lower than 3200 MHz to higher than 3200 MHz, so that the low-pass filter can suppress the harmonic wave to obtain good overall filter performance.
[0069] In this embodiment, the dielectric filter is the dielectric filter 100 provided in the first embodiment. The structure and function of the dielectric filter 100 have been described in detail in the first embodiment, and therefore details are not described herein again.
[0070] In another embodiment, the dielectric filter may also be the another dielectric filter provided in the first embodiment. Referring to FIG. 11, FIG. 11 shows a base station 2000 according to a third embodiment of the present invention. The base station 2000 includes the dielectric filter 100 provided in the first embodiment or the dielectric filter component 1000 provided in the second embodiment.
[0071] The dielectric filter component 1000 includes a low-pass filter 1100 and a dielectric filter. The low-pass filter 1100 is cascaded with the dielectric filter, to achieve better filter performance. The dielectric filter is the dielectric filter 100 provided in the first embodiment. The structure and function of the dielectric filter 100 have been described in detail in the first embodiment, and therefore details are not described herein again.
[0072] The dielectric filter may also be the another dielectric filter provided in the first embodiment.
[0073] Optionally, the dielectric filter 100 is also applied to a radio frequency module. Optionally, the radio frequency module may be a radio frequency module in the base station 2000, or may be a radio frequency module in another communications device, such as in a radar system.
[0074] Optionally, the dielectric filter 100 may also be used for a transceiver, and the like. The transceiver may also be a module in the base station 2000.
[0075] In this embodiment, the base station 2000 includes the dielectric filter component 1000. The dielectric filter component 1000 includes the low-pass filter 1100 and the dielectric filter 100. The dielectric filter 100 includes the connecting rib 50. The connecting rib 50 is accommodated in an accommodating cavity 11. A shortest distance between the connecting rib 50 and a main medium 23 is greater than a preset value. Because the connecting rib 50 is orthogonal to a magnetic field of a high-order harmonic wave of the dielectric filter 100, the connecting rib 50 affects a path of the magnetic field, resulting in a change in a frequency of the high-order harmonic wave. Further, because the connecting rib 50 is disposed inside the accommodating cavity 11, a volume of air in the accommodating cavity 11 becomes smaller, so that a frequency of the high-order harmonic wave becomes higher. Therefore, a function of pushing away the high-order harmonic wave is implemented. The base station 2000 of the present invention also maintains performance of the TEoi mode when pushing away the high-order harmonic wave for suppression.
[0076] Finally, it should be noted that the foregoing embodiments are merely intended for describing the technical solutions of the present invention, but not for limiting the present invention. Although the present invention is described in detail with reference to the foregoing embodiments, a person of ordinary skill in the art should understand that the descriptions are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
1. A dielectric filter, comprising:
a cavity, wherein the cavity comprises an accommodating cavity and a cavity wall surrounding the accommodating cavity;
a resonator, wherein the resonator is disposed inside the accommodating cavity, the resonator comprises a support medium and a main medium, the support medium is disposed on a bottom wall of the accommodating cavity, and the main medium is disposed on the support medium;
a cover plate, wherein the cover plate covers the cavity to close the accommodating cavity; and
a connecting rib, wherein the connecting rib is accommodated in the accommodating cavity, and is disposed on a radiation plane formed between a radiation radiated from a center axis of the resonator onto the cavity wall and the center axis of the resonator, wherein a shortest distance between the connecting rib and the main medium is greater than a preset value.
2. The dielectric filter according to claim 1, wherein the connecting rib is disposed
on at least one of the bottom wall of the accommodating cavity, the cover plate, or
the cavity wall of the accommodating cavity.
3. The dielectric filter according to claim 2, wherein the dielectric filter further
comprises a tuning member, the tuning member is disposed on the cover plate, and a
center axis of the tuning member is the same as a center axis of the cover plate;
when the connecting rib is disposed on at least one of the bottom wall of the accommodating
cavity or the cavity wall of the accommodating cavity, the connecting rib is connected
to the support medium and the cavity wall of the accommodating cavity; and when the
connecting rib is disposed on the cover plate, the connecting rib is connected to
the tuning member and the cavity wall of the accommodating cavity.
4. The dielectric filter according to claim 2 or 3, wherein the radiation plane forms
a first projection on the bottom wall; when the connecting rib is disposed on the
bottom wall of the accommodating cavity, the connecting rib forms a second projection
on the bottom wall, and the second projection overlaps with the first projection on
a center line in a direction from the resonator to the cavity wall; when the connecting
rib is disposed on the cavity wall, the connecting rib forms a third projection on
the bottom wall, and the third projection overlaps with the first projection on the
center line in the direction from the resonator to the cavity wall; and when the connecting
rib is disposed on the cover plate, the connecting rib forms a fourth projection on
the cover plate, and the fourth projection overlaps with the first projection on a
center line in a direction from the center axis of the cover plate to the cavity wall.
5. The dielectric filter according to any one of claims 2 to 4, wherein when the connecting
rib is disposed on the bottom wall of the accommodating cavity, the connecting rib
is integrated with the bottom wall; when the connecting rib is disposed on the cavity
wall of the accommodating cavity, the connecting rib is integrated with the cavity
wall; and when the connecting rib is disposed on the cover plate, the connecting rib
is integrated with the cover plate.
6. The dielectric filter according to any one of claims 1 to 5, wherein the connecting
rib comprises a support part and a first extending part that is formed by extending
a first end of the support part in a direction away from the support part, and shortest
distances between the support part and the main medium and between the first extending
part and the main medium are greater than the preset value.
7. The dielectric filter according to claim 6, wherein the connecting rib further comprises
a second extending part, the second extending part is formed by extending, in a direction
away from the support part, a second end that is of the support part and that is opposite
to the first end, wherein a shortest distance between the second extending part and
the main medium is greater than the preset value.
8. The dielectric filter according to any one of claims 1 to 7, wherein there are at
least two connecting ribs; and with the center axis of the resonator as a center line,
the at least two connecting ribs are evenly arranged around the center line.
9. The dielectric filter according to claims 2 to 8, wherein when connecting ribs are
disposed on any two of the bottom wall, the cavity wall, and the cover plate, the
connecting ribs disposed on the any two of the bottom wall, the cavity wall, and the
cover plate are not in contact with each other; or when connecting ribs are disposed
on all the bottom wall, the cavity wall, and the cover plate, the connecting ribs
disposed on the bottom wall, the cavity wall, and the cover plate are not in contact
with each other.
10. The dielectric filter according to any one of claims 1 to 9, wherein the preset value
is 2 mm.
11. A dielectric filter component, comprising a low-pass filter and the dielectric resonator
according to any one of claims 1 to 10, wherein the low-pass filter is cascaded with
the dielectric filter.
12. Abase station, comprising the dielectric filter component according to claim 11.