filter

Abstract

This application provides a filter including at least one resonant cavity unit. Each resonant cavity unit includes: a housing, with a resonant cavity formed inside the housing, and a tuning hole on the top wall of the resonant cavity; a tuning rod inserted into the resonant cavity through the tuning hole, the tuning rod being able to move up and down relative to the resonant cavity along the height direction of the resonant cavity unit to adjust the resonant frequency of the resonant cavity; wherein, the tuning rod includes a first dielectric segment and a second dielectric segment arranged sequentially from top to bottom, and during the up and down movement of the tuning rod, the second dielectric segment is at least partially located inside the resonant cavity; wherein, the relative permittivity Er2 of the second dielectric segment is greater than the relative permittivity Er1 of the first dielectric segment. The filter provided by this application can achieve a wide tuning frequency range while keeping the signal leakage at a low level, thereby giving the filter better performance indicators.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a filter. Background Technology

[0002] Microwave communication systems are communication systems based on microwave point-to-point technology. In recent years, they have been widely used in various occasions such as large-scale events, disaster relief, oil fields, and optical network replenishment.

[0003] The outdoor unit (ODU) is the core unit of a microwave communication system. Microwave communication systems operate on numerous frequency bands and sub-bands. In some systems, the ODU is a fixed-band ODU (meaning it applies only to a specific sub-band). In such systems, each sub-band requires the development of an independent microwave ODU module, making the product coding of the microwave communication system (different ODUs correspond to different product codes) extremely complex, thus resulting in high development, management, and manufacturing costs.

[0004] Wideband microwave ODUs (or simply "wideband ODUs") can solve the problem of complex product coding. Wideband ODUs can operate on multiple different sub-bands, offering the following advantages over fixed-band ODUs: multiple sub-bands can share a single wideband ODU product, thereby reducing the manufacturing cost of microwave communication systems; flexible market availability with arbitrary frequency band configuration, meeting urgent market delivery needs; and reduced system development and operation costs associated with complex product coding.

[0005] The working frequency adjustable filter is a key component of a broadband ODU. Currently, the performance of the working frequency adjustable filter needs to be optimized and improved. Summary of the Invention

[0006] Some embodiments of this application provide a filter. The following describes this application from multiple aspects, and the embodiments and beneficial effects of the following aspects can be referred to each other.

[0007] In a first aspect, embodiments of this application provide a filter, including at least one resonant cavity unit. Each resonant cavity unit includes: a housing, with a resonant cavity formed inside the housing, and a tuning hole formed on the top wall of the resonant cavity; a tuning rod, inserted into the resonant cavity through the tuning hole, the tuning rod being capable of moving up and down relative to the resonant cavity along the height direction of the resonant cavity unit to adjust the resonant frequency of the resonant cavity unit; wherein, the tuning rod includes a first dielectric segment and a second dielectric segment connected sequentially from top to bottom, and during the up and down movement of the tuning rod, the second dielectric segment is at least partially located inside the resonant cavity; wherein, the relative permittivity Er2 of the second dielectric segment is greater than the relative permittivity Er1 of the first dielectric segment.

[0008] According to the embodiments of this application, the filter can achieve a wide tuning frequency range while keeping the signal leakage at a low level, thereby giving the filter better performance indicators.

[0009] In some embodiments, the wall thickness of the top wall of the resonant cavity is greater than or equal to the lifting stroke of the frequency modulation rod; wherein, when the frequency modulation rod is at the upper limit position of its lifting stroke, the interface between the first dielectric segment and the second dielectric segment is not higher than the upper surface of the top wall.

[0010] According to the embodiments of this application, during the complete lifting and lowering stroke of the frequency modulation rod, the internal medium is always the second medium segment (high Er medium), and the external medium is always the first medium segment (low Er medium), which further ensures that the filter has a sufficiently wide tuning frequency range and can keep the signal leakage at a low level.

[0011] In some implementations, 1 < Er1 ≤ 3, Er2 ≥ 5.

[0012] In some embodiments, at least one resonant cavity unit includes a first unit, the resonant cavity of the first unit is a first resonant cavity, and the tuning rod of the first unit includes a first tuning rod and a second tuning rod; wherein the first tuning rod and the second tuning rod are located on different sides of the central axis of the first resonant cavity.

[0013] According to the embodiments of this application, the frequency variation linearity of the resonant cavity unit can be improved, and the control precision requirements of the motor can be reduced.

[0014] In some embodiments, in a planar reference frame perpendicular to the central axis of the resonant cavity and with the location of the central axis of the resonant cavity as the origin, the difference between the azimuth angle of the first tuning rod and the azimuth angle of the second tuning rod is 45° to 180°.

[0015] In some embodiments, at least one resonant cavity unit includes a plurality of adjacent first units; each first unit has a first coupling window and a second coupling window on its sidewall; the first unit is coupled to a first adjacent unit of the first unit through the first coupling window and to a second adjacent unit of the first unit through the second coupling window; wherein, the first tuning rod is located in the half cavity of the first resonant cavity corresponding to the first coupling window, and the second tuning rod is located in the half cavity of the first resonant cavity corresponding to the second coupling window.

[0016] According to the embodiments of this application, a coupling compensation structure can be formed between adjacent resonant cavity units to improve the performance parameters of the filter, for example, to make the passband width of the filter substantially the same at each operating position.

[0017] In some embodiments, a third coupling window is also provided on the side wall of the first unit, and the first unit is coupled to the third adjacent unit of the first unit through the third coupling window; wherein, the second frequency tuning rod is located in the half cavity of the first resonant cavity corresponding to the second coupling window, and is also located in the half cavity of the first resonant cavity corresponding to the third coupling window.

[0018] In some embodiments, a third coupling window is also provided on the side wall of the first unit, and the first unit is coupled to the third adjacent unit of the first unit through the third coupling window; the frequency tuning rod of the first unit also includes a third frequency tuning rod, wherein the third frequency tuning rod is located in the half cavity of the first resonant cavity corresponding to the third coupling window.

[0019] In some embodiments, the adjacent units of the first unit are one of the following: other resonant cavity units in at least one resonant cavity unit; a signal input unit that inputs a signal to the filter; and a signal output unit that receives the output signal of the filter.

[0020] In some embodiments, the distance between the central axis of the first tuning rod and the central axis of the first resonant cavity is a first distance, and the distance between the central axis of the second tuning rod and the central axis of the first resonant cavity is a second distance; at least one resonant cavity unit includes a plurality of adjacent first units, wherein the plurality of first distances corresponding to the plurality of first units are equal to each other, and the plurality of second distances corresponding to the plurality of first units are equal to each other.

[0021] In some implementations, the first distance is equal to the second distance.

[0022] In some implementations, multiple first units are arranged in a linear topology, a CQ topology, or a CT topology.

[0023] In some implementations, the outer diameter of the tuning rod is greater than or equal to 1 mm; and / or, the distance between the tuning rod and the sidewall of the resonant cavity is greater than or equal to 1 mm.

[0024] Secondly, embodiments of this application provide a filter, including at least one resonant cavity unit. The at least one resonant cavity unit includes a first unit, which includes: a housing, with a first resonant cavity formed inside the housing, and a tuning hole provided on the top wall of the first resonant cavity; and a tuning rod, which is inserted into the first resonant cavity through the tuning hole. The tuning rod can move up and down relative to the resonant cavity along the height direction of the resonant cavity unit to adjust the resonant frequency of the resonant cavity unit. The tuning rod includes a first tuning rod and a second tuning rod, which are located on different sides of the central axis of the first resonant cavity.

[0025] In some embodiments, in a planar reference frame perpendicular to the central axis of the resonant cavity and with the location of the central axis of the resonant cavity as the origin, the difference between the azimuth angle of the first tuning rod and the azimuth angle of the second tuning rod is 45° to 180°.

[0026] In some embodiments, at least one resonant cavity unit includes a plurality of adjacent first units; each first unit has a first coupling window and a second coupling window on its sidewall; the first unit is coupled to a first adjacent unit of the first unit through the first coupling window and to a second adjacent unit of the first unit through the second coupling window; wherein, the first tuning rod is located in the half cavity of the first resonant cavity corresponding to the first coupling window, and the second tuning rod is located in the half cavity of the first resonant cavity corresponding to the second coupling window.

[0027] In some embodiments, a third coupling window is also provided on the side wall of the first unit, and the first unit is coupled to the third adjacent unit of the first unit through the third coupling window; wherein, the second frequency tuning rod is located in the half cavity of the first resonant cavity corresponding to the second coupling window, and is also located in the half cavity of the first resonant cavity corresponding to the third coupling window.

[0028] In some embodiments, a third coupling window is also provided on the side wall of the first unit, and the first unit is coupled to the third adjacent unit of the first unit through the third coupling window; the frequency tuning rod of the first unit also includes a third frequency tuning rod, wherein the third frequency tuning rod is located in the half cavity of the first resonant cavity corresponding to the third coupling window.

[0029] In some embodiments, the adjacent units of the first unit are one of the following: other resonant cavity units in at least one resonant cavity unit; a signal input unit that inputs a signal to the filter; and a signal output unit that receives the output signal of the filter.

[0030] In some embodiments, the distance between the central axis of the first tuning rod and the central axis of the first resonant cavity is a first distance, and the distance between the central axis of the second tuning rod and the central axis of the first resonant cavity is a second distance; at least one resonant cavity unit includes a plurality of adjacent first units, wherein the plurality of first distances corresponding to the plurality of first units are equal to each other, and the plurality of second distances corresponding to the plurality of first units are equal to each other.

[0031] In some implementations, the first distance is equal to the second distance.

[0032] In some implementations, multiple first units are arranged in a linear topology, a CQ topology, or a CT topology.

[0033] In some implementations, the outer diameter of the tuning rod is greater than or equal to 1 mm; and / or, the distance between the tuning rod and the sidewall of the resonant cavity is greater than or equal to 1 mm. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of a microwave communication system provided in an embodiment of this application;

[0035] Figure 2 An exemplary functional structure diagram of a microwave outdoor unit (ODU) provided in an embodiment of this application;

[0036] Figure 3 This application provides an exemplary operating frequency band for a microwave communication system provided in its embodiments.

[0037] Figure 4 An exemplary structural diagram (exploded view) of the filter provided in an embodiment of this application;

[0038] Figure 5 This is an exemplary structural diagram of a filter in some implementations;

[0039] Figure 6 This diagram illustrates the operating performance of filters in some implementations. Figure 1 ;

[0040] Figure 7 This is a schematic diagram illustrating the signal leakage of filters in some implementations;

[0041] Figure 8 Exemplary structure of the filter provided in the embodiments of this application Figure 1 ;

[0042] Figure 9 Exemplary structure of the resonant cavity unit provided in the embodiments of this application Figure 1 ;

[0043] Figure 10 Exemplary structure of the resonant cavity unit provided in the embodiments of this application Figure 2 ;

[0044] Figure 11 Exemplary structure of the filter provided in the embodiments of this application Figure 2 ;

[0045] Figure 12 Exemplary structure of the resonant cavity unit provided in the embodiments of this application Figure 3 ;

[0046] Figure 13 This is a schematic diagram illustrating the working performance of the resonant cavity unit provided in the embodiments of this application;

[0047] Figure 14 Exemplary structure of the resonant cavity unit provided in the embodiments of this application Figure 4 ;

[0048] Figure 15This diagram illustrates the operating performance of filters in some implementations. Figure 2 ;

[0049] Figure 16 Exemplary structure of the filter provided in the embodiments of this application Figure 3 ;

[0050] Figure 17 Exemplary structure of the resonant cavity unit provided in the embodiments of this application Figure 5 ;

[0051] Figure 18 Exemplary structure of the resonant cavity unit provided in the embodiments of this application Figure 6 ;

[0052] Figure 19 A schematic diagram of the working performance of the filter provided in the embodiments of this application. Figure 1 ;

[0053] Figure 20 A schematic diagram of the working performance of the filter provided in the embodiments of this application. Figure 2 ;

[0054] Figure 21 Exemplary structure of the filter provided in the embodiments of this application Figure 4 ;

[0055] Figure 22 Exemplary structure of the filter provided in the embodiments of this application Figure 5 ;

[0056] Figure 23 This is a schematic diagram of the filter structure in some other implementations. Detailed Implementation

[0057] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0058] This application provides a filter that exhibits improved performance over a wide tuning frequency range. Specific embodiments are described below.

[0059] Figure 1 Exemplary application scenarios of embodiments of this application are shown. Figure 1 It includes a microwave communication system, which consists of an indoor microwave unit (IDU), intermediate frequency cables, an outdoor microwave unit (ODU), and microwave antennas.

[0060] The IDU is the indoor part of the microwave communication system, mainly used for baseband processing of service signals and mutual conversion between baseband signals and intermediate frequency analog signals; the intermediate frequency cable is used to transmit intermediate frequency analog signals (including service signals and management signals) between the IDU and ODU; the ODU is the outdoor part of the microwave communication system, used to convert between intermediate frequency analog signals and radio frequency signals; the microwave antenna (referred to as "antenna") is used to provide directional transmission and reception of radio frequency signals.

[0061] Figure 2 The functional structure diagram of the ODU is shown. (Reference) Figure 2 The ODU includes a microwave board, a duplexer, and an antenna port. The microwave board is the processing module within the ODU that handles signal transmission and reception. The microwave board includes a TX link (or "transmit link") and a TR link (or "receive link"). The duplexer includes a TX filter and a TR filter; the TX link on the microwave board connects to the TX filter in the duplexer, and the TR link connects to the TR filter in the duplexer. The duplexer also includes an ANT common port, through which the TX and TR filters are connected to the antenna.

[0062] During signal transmission, the signal from the microwave board's TX link is sent to the TX filter of the duplexer. After filtering, the TX filter transmits the valid signal through the antenna. During signal reception, the signal received by the antenna is sent to the TR filter of the duplexer. After filtering, the TR filter transmits the valid signal to the microwave board. The TX and RX filters are structurally combined via an ANT common port, allowing the TX and RX links to operate at different frequencies simultaneously.

[0063] Microwave communication systems typically have a set operating frequency band. Figure 3 An exemplary operating frequency band for a microwave communication system is shown. Figure 3 In this context, the operating frequency band of the microwave communication system is F to F+600MHz, meaning the starting operating frequency of the microwave communication system is F, the ending operating frequency is F+600MHz, and the bandwidth is 600MHz. For microwave communication systems, F can be 6GHz to 100GHz, for example, 6GHz, 7GHz, 20GHz, 100GHz, etc.

[0064] refer to Figure 3 Microwave communication systems operate within multiple sub-bands. A fixed-band ODU can only operate within a single sub-band. To achieve communication across the entire operating frequency band, multiple fixed-band ODUs need to be configured in the microwave communication system. This not only increases hardware costs but also the number of product codes, hindering subsequent management and operation of the microwave communication system.

[0065] Replacing fixed-band ODUs with wideband ODUs can improve this situation. Wideband ODUs can operate on multiple sub-bands, thus reducing the number of ODUs in a microwave communication system. In practical applications, it is desirable for wideband ODUs to cover the widest possible operating frequency band to simplify the microwave communication system as much as possible.

[0066] The core component of a broadband ODU is the tunable duplexer. As mentioned above, the tunable duplexer includes a TX filter, an RX filter, and an ANT common port. Currently, the ANT common port is not the technological bottleneck of the tunable duplexer; the key technology of a broadband ODU is the tunable filter (including the TX and RX filters). The goal is for the tunable filter to have the widest possible tuning frequency range to cover the widest possible operating frequency band, thereby achieving high performance and low cost in microwave communication systems.

[0067] Figure 4 An exemplary external structural diagram (exploded view) of a tunable filter (hereinafter referred to as "filter") is shown. In the embodiments described herein, the filter can be implemented as a TX filter or an RX filter. Reference Figure 4 The filter includes a motor assembly and a transmission plate, the motor assembly driving the transmission plate to move up and down. The filter also includes one or more resonant cavities, each containing a frequency tuning rod. The top of the frequency tuning rod is connected to the transmission plate, and during the up-and-down movement of the transmission plate, it drives the frequency tuning rod to move up and down relative to the resonant cavity. In this embodiment, the direction of the frequency tuning rod's up-and-down movement is referred to as the height direction of the filter (the X direction in each figure).

[0068] The working frequency of the filter can be adjusted by moving the tuning lever up and down. In other words, the filter changes its working frequency (or "working position") by one position for each change in the height of the tuning lever. When the tuning lever moves from the upper limit to the lower limit of its travel, the working frequency range that the filter can cover is the tuning frequency range of the filter.

[0069] Figure 5 The internal structure diagram of filter 100' in some implementations is shown. (Reference) Figure 5 The filter 100' includes multiple resonant cavity units 110', labeled 110a' to 110g'. Adjacent resonant cavity units 110' are coupled through coupling windows 170'. Each resonant cavity unit 110' includes a resonant cavity 130' and a frequency modulation rod 140' inserted in the resonant cavity 130'. Exemplarily, the frequency modulation rod 140' can be implemented as a screw.

[0070] Figure 5In the filter 100' shown, the frequency modulation lever 140' is composed of a single dielectric material (hereinafter referred to as a "single dielectric frequency modulation lever"). Its specific material can be a metal dielectric, quartz dielectric, ceramic dielectric, etc., and this application does not limit this. For a single dielectric frequency modulation lever, when its relative permittivity (represented by the letter Er) is small (for example, when Er is below 3), the tuning frequency range of the filter 100' is small; when its Er is large, the signal leakage of the filter 100' is more severe.

[0071] refer to Figure 6 (a) shows the tuning frequency range of a filter 100' (7G band) when the tuning lever 140' uses a low Er medium. Figure 6 In (a), the horizontal axis represents the length of the cavity section of the frequency modulation rod 140' (i.e., the length of the frequency modulation rod 140' extending into the resonant cavity 130', in mm), and the vertical axis represents the operating frequency of the filter 100'. Figure 6 In (a), when the relative permittivity Er of the frequency modulation rod 140' is 3, when the length of the cavity section of the frequency modulation rod 140' changes from 1 mm to 6 mm, the tuning frequency range of the filter 100' is less than 300 MHz.

[0072] Using a frequency modulation arm 140' with a high dielectric constant Er can increase the tuning frequency range of filter 100', but a high dielectric constant frequency modulation arm 140' will increase the signal leakage level of filter 100'. (Reference) Figure 6 (b) In another example, the relative permittivity Er of the tuning bar 140' is 6. Figure 6 In (b), when the length of the cavity section of the frequency modulation rod 140' changes from 1 mm to 6 mm, the tuning frequency range of the filter 100' increases to over 600 MHz.

[0073] However, reference Figure 7 Compared to the scheme with Er=3 ( Figure 6 (a) Scheme shown. Figure 6 In the scheme shown in (b), the signal leakage of filter 100' is significantly increased.

[0074] The desired outcome is that the filter has a wide tuning frequency range while keeping the signal leakage at a low level, in order to improve the filter's performance (e.g., to keep the filter with substantially the same passband width at all operating positions).

[0075] Therefore, this embodiment provides a filter 100. Figure 8 An exemplary structural diagram (front view) of the filter 100 provided in this embodiment is shown. (Refer to...) Figure 8The filter 100 includes multiple resonant cavity units 110, specifically resonant cavity units 110a to 110g. In this embodiment, the number of resonant cavity units 110 is 7, but this application is not limited to this. In other embodiments, the number of resonant cavity units 110 can be one or more other numbers, such as 1, 3, 10, 15, etc.

[0076] It should be noted that, in this article, the lowercase letters at the end of the reference numerals are used to distinguish different resonant cavity units. For example, reference numerals "110a" and "110b" are used to represent two different resonant cavity units. When it is not necessary to distinguish between different resonant cavity units, the lowercase letters at the end of the reference numerals will be omitted. For example, reference numeral "110" can represent any resonant cavity unit.

[0077] Figure 9 A schematic diagram of one of the resonant cavity units 110 is shown. Figure 9 (a) is a front view of the resonant cavity unit 110. Figure 9 (b) is a cross-sectional view of the resonant cavity unit 110 (specifically...). Figure 9 (a) BB cross-section view). Reference Figure 9 The resonant cavity unit 110 includes a housing 120, and a resonant cavity 130 is formed inside the housing 120. (Reference) Figure 9 (b) In this embodiment, the cross-section of the resonant cavity 130 is rectangular (i.e., the shape of the resonant cavity 130 is cubic). However, this application is not limited to this. For example, in other embodiments, the cross-section of the resonant cavity 130 can be circular (e.g., Figure 9 As shown in (c), the shape of the resonant cavity 130 can be cylindrical, elliptical, polygonal, irregular, etc., and this application does not limit it.

[0078] The resonant cavity unit 110 also includes a frequency modulation rod 140, which is inserted into the resonant cavity 130 and can move up and down relative to the resonant cavity 130 along the height direction of the resonant cavity unit 110 (i.e., the height direction of the filter 100, the X direction in the figures). Exemplarily, the extension direction of the frequency modulation rod 140 is parallel to the height direction of the resonant cavity unit 110 (hereinafter referred to as the "height direction"). It should be noted that the height direction of the resonant cavity unit 110 is a relative direction and can change with the placement orientation of the filter 100. For example, when the filter 100 is positioned according to… Figure 8 When placed in the indicated orientation, the height direction of the resonant cavity unit 110 is vertical; when the filter 100 is relative to... Figure 8 When the shown orientation is rotated 90° outward from the paper, the height direction of the resonant cavity unit 110 is horizontal.

[0079] Continue to refer to Figure 9The housing 120 includes a top wall 121, a bottom wall 122, and a side wall 123 of the resonant cavity 130. The bottom wall 122 and side wall 123 of the resonant cavity 130 are made of metal and can be integrally formed from metal. The top wall 121 of the resonant cavity 130 is also made of metal and serves as a cover plate for covering the upper opening of the resonant cavity 130. A tuning hole 124 is provided on the top wall 121, and a tuning rod 140 is inserted into the resonant cavity 130 through the tuning hole 124. The medium between the tuning hole 124 and the tuning rod 140 is air. Exemplarily, the resonant cavity unit 110 may also include a resonant rod 150 disposed in the resonant cavity 130. The resonant rod 150 can be made of metal. The resonant rod 150 can be integrally formed with the bottom wall 122 and side wall 123 of the resonant cavity 130, or the resonant rod 150 can be mounted on the bottom wall 122 of the resonant cavity 130 using screws or other connecting structures.

[0080] The top of the tuning lever 140 is connected to the transmission plate 160 (e.g., by riveting, adhesive application, etc.). When the transmission plate 160 moves up and down in the height direction under the drive of the motor, it can drive the tuning lever 140 to move up and down synchronously. Referring to the above, when the tuning lever 140 is raised or lowered to different height positions, the resonant cavity unit 110 has different resonant frequencies. In addition, the diameter of the tuning hole 124 can be determined according to the positional accuracy of the motor in the lateral direction (perpendicular to the height direction). Without interfering with the raising and lowering movement of the tuning lever 140, the smaller the size of the tuning hole 124, the better (a smaller tuning hole 124 helps to further avoid signal leakage in the resonant cavity 130).

[0081] It should be noted that the directional terms such as "upper", "lower", "left", "right", "top", and "bottom" in this application are all based on the height direction of the resonant cavity unit and are relative concepts. They do not indicate or imply that the component referred to must have a specific orientation. They can change accordingly according to actual use and should not be construed as limiting this application.

[0082] In this embodiment, reference Figure 9 (a) The frequency modulation lever 140 is not a single-medium frequency modulation lever, but a hybrid-medium frequency modulation lever. Specifically, the frequency modulation lever 140 includes two dielectric segments with different Er, namely a first dielectric segment 141 and a second dielectric segment 142. The first dielectric segment 141 and the second dielectric segment 142 are connected sequentially from top to bottom.

[0083] The relative permittivity Er2 of the second dielectric segment 142 is greater than the relative permittivity Er1 of the first dielectric segment 141. That is, the second dielectric segment 142 has a higher relative permittivity, while the first dielectric segment 141 has a lower relative permittivity. For example, Er2 ≥ 5, such as Er2 being 6, 9, 13.5, etc.; 1 < Er1 ≤ 3, such as Er1 being 2 or 3. Based on this, Er1 and Er2 can be arbitrarily combined. The first dielectric segment 141 / second dielectric segment 142 can be made of materials such as plastic, quartz, or ceramic, and the two can be combined through integrated injection molding, hot-melt splicing, etc.

[0084] In this embodiment, during the lifting and lowering movement of the frequency modulation lever 140, the second dielectric segment 142 is at least partially located inside the resonant cavity 130. That is, regardless of the height position of the frequency modulation lever 140 during its lifting and lowering stroke, the second dielectric segment 142 can serve as the intracavity dielectric of the resonant cavity unit 110 and influence the resonant frequency of the resonant cavity unit 110. Since the second dielectric segment 142 has a high relative permittivity, using the second dielectric segment 142 as the intracavity dielectric of the resonant cavity unit 110 can improve the tuning frequency range of the filter 100.

[0085] Furthermore, the frequency modulation lever 140 is not entirely composed of the second dielectric segment 142, but also includes a first dielectric segment 141 located above the second dielectric segment 142. Since the first dielectric segment 141 has a relatively low Er, the filter 100 provided in this embodiment can achieve a wide tuning frequency range while keeping the signal leakage at a low level, thereby giving the filter 100 better performance indicators.

[0086] For example, in a specific example of this embodiment, a filter 100 in a certain 7GHz band has Er1 = 2 for its first dielectric segment 141 and Er2 = 6 for its second dielectric segment 142. Prototype simulation shows that in this example, the tuning frequency range of the filter 100 is above 1GHz. Compared to a single dielectric frequency modulator (Er = 3) scheme (as mentioned above, the tuning frequency range of this scheme is below 300MHz), the tuning frequency range of the filter 100 provided in this embodiment is increased by more than 300%. Furthermore, as Er2 of the second dielectric segment 142 increases, the tuning frequency range of the filter 100 can theoretically continue to increase. Additionally, in this embodiment, the signal leakage level of the filter 100 is essentially equivalent to the signal leakage level of a low-Er single dielectric frequency modulator 140 (Er = 3) filter.

[0087] In this embodiment, the thickness of the top wall 121 is determined according to the required lifting stroke of the frequency modulation lever 140. Specifically, the thickness of the top wall 121 is greater than or equal to the lifting stroke of the frequency modulation lever 140. This ensures that the interface 143 between the first and second frequency modulation levers 140 is always within the thickness range of the top wall 121. That is, when the frequency modulation lever 140 is at the upper limit of its lifting stroke, the interface 143 is not higher than the upper surface of the top wall 121; when the frequency modulation lever 140 is at the lower limit of its lifting stroke, the interface 143 is not lower than the lower surface of the top wall 121. Thus, during the complete lifting stroke of the frequency modulation lever 140, the intracavity medium is always the second medium segment 142 (high Er medium), and the extracavity medium is always the first medium segment 141 (low Er medium), further ensuring that the filter 100 has a sufficiently wide tuning frequency range and that signal leakage is kept at a low level. However, this application is not limited to this. For example, in other embodiments, when the tuning lever 140 is at the lower limit of its lifting stroke, the interface 143 may be lower than the lower surface of the top wall 121. In this case, the first dielectric segment 141 may be partially located in the resonant cavity 130.

[0088] In one example, the tuning frequency range of filter 100 is 600MHz. To meet this tuning frequency range, the lifting stroke of tuning lever 140 is 4.5mm. In this example, the thickness of top wall 121 is set to 5mm. That is, the thickness of top wall 121 is greater than the lifting stroke of tuning lever 140. This allows for a certain distance margin between interface 143 and the upper / lower surfaces of top wall 121 when tuning lever 140 is at its upper / lower limit, reducing the control precision requirements on the motor. For example, when tuning lever 140 is at its upper limit, interface 143 is located 0.2mm below the upper surface of top wall 121; when tuning lever 140 is at its lower limit, interface 143 is located 0.3mm above the lower surface of top wall 121. This application is not limited to this. In other examples, the thickness of the cover plate can be equal to the lifting stroke of tuning lever 140.

[0089] This embodiment is an exemplary description of the technical solution of this application, and those skilled in the art can make other modifications.

[0090] For example, in this embodiment, the frequency modulation lever 140 is composed of two dielectric segments (a first dielectric segment 141 and a second dielectric segment 142). In other embodiments, the frequency modulation lever 140 may be composed of more than two dielectric segments. For example, the frequency modulation lever 140 may include a third dielectric segment located between the first dielectric segment 141 and the transmission plate 160, and the relative permittivity Er3 of the third dielectric segment may be less than the relative permittivity Er1 of the first dielectric segment 141.

[0091] For example, in this embodiment, the tuning hole 124 is formed by a through hole machined in the top wall 121. In other embodiments, the tuning hole 124 may be formed in other ways. For example, see Reference Figure 10 In some embodiments, the tuning hole 124 is formed by the inner cavity of the hollow stud 125. In this embodiment, a threaded hole is provided on the top wall 121, through which the hollow stud 125 is screwed into the top wall 121. In this embodiment, the hollow stud 125 can be regarded as part of the top wall 121, which can increase the local thickness of the top wall 121, allowing the tuning rod 140 to have a larger lifting stroke.

[0092] The hybrid dielectric frequency modulation lever scheme provided in this embodiment has been described above. Based on this scheme, this application embodiment also provides another filter. Specifically, in this embodiment, the number of frequency modulation levers in the resonant cavity unit is split from one to two. This embodiment can improve the linearity of the frequency change of the resonant cavity unit. For ease of description, a resonant cavity unit with one frequency modulation lever is referred to as a "single frequency modulation lever unit," and a resonant cavity unit with two frequency modulation levers is referred to as a "double frequency modulation lever unit."

[0093] In a single-frequency modulation (FM) lever unit, the modulation lever typically has a large outer diameter, and the electromagnetic field in the resonant cavity is concentrated near the lever (usually the central region of the resonant cavity). This results in poor linearity of frequency change in the resonant cavity unit during the modulation lever's raising and lowering. In other words, as the height of the modulation lever changes, the resonant frequency of the resonant cavity unit changes in a curved (e.g., exponential) manner, leading to high tuning sensitivity of the filter. This makes adjusting the height of the modulation lever difficult, thereby increasing the precision requirements for motor control.

[0094] Therefore, this embodiment provides a filter to solve the above problems. Figure 11 An exemplary structural diagram of the filter 200 provided in this embodiment is shown. Wherein, Figure 11 (a) is the front view of filter 200. Figure 11 (b) is a cross-sectional view of filter 200. (Reference) Figure 11 The filter 200 includes multiple resonant cavity units 210 (resonant cavity units 210a to 210g, respectively). In this embodiment, the filter 200 has 7 resonant cavity units 210. In other embodiments, the resonant cavity units 210 can be one or more other numbers, such as 2, 10, etc.

[0095] The resonant cavity unit 210 of the filter 200 includes at least one dual-frequency-modulating bar unit (as the first unit). In this embodiment, resonant cavity units 210a to 210g are all dual-frequency-modulating bar units. In other embodiments, some resonant cavity units 210 (e.g., unit 210g) in the filter 200 may not be dual-frequency-modulating bar units.

[0096] Figure 12 An exemplary structural diagram of the resonant cavity unit 210 provided in this embodiment is shown. Wherein, Figure 12 (a) is a front view of the resonant cavity unit 210. Figure 12 (b) is a cross-sectional view of the resonant cavity unit 210 (specifically, the CC cross-sectional view of Figure 12(a)). Reference Figure 12 The resonant cavity unit 210 includes a housing 220, inside which a resonant cavity 230 (serving as a first resonant cavity) is formed, with the central axis of the resonant cavity 230 being the axis M. The resonant cavity unit 210 also includes two tuning rods 240, namely a first tuning rod 244 and a second tuning rod 245, which are respectively inserted into the resonant cavity 230 through a first tuning hole 226 and a second tuning hole 227 formed on the top wall 221. Exemplarily, both the first tuning rod 244 and the second tuning rod 245 extend along the height direction of the resonant cavity unit 210 (the X direction in the figures), that is, the central axis M1 of the first tuning rod 244 and the central axis M2 of the second tuning rod 245 are parallel to the height direction of the resonant cavity unit 210 (hereinafter referred to as the "height direction"). The top ends of each tuning lever 240 in the resonant cavity unit 210 are connected to the transmission plate 260. Driven by the motor, the transmission plate 260 can drive each tuning lever 240 to move up and down synchronously relative to the resonant cavity 230, thereby adjusting the resonant frequency of the resonant cavity unit 210. Other undescribed structures of the housing 220, tuning holes, and tuning levers 240 are similar to... Figures 8-10 The structures shown are essentially the same, therefore you can refer to the above text regarding... Figures 8-10 The description is omitted.

[0097] Furthermore, the two tuning levers 240 are located on different sides of the central axis M of the resonant cavity 230. In this embodiment, the first tuning lever 244 is located on the left side of the central axis M, and the second tuning lever 245 is located on the right side of the central axis M. However, this application is not limited to this. For example, in another embodiment, the first tuning lever 244 is located on the upper left side of the central axis M, and the second tuning lever 245 is located on the lower left side of the central axis M.

[0098] The central axis M of the resonant cavity 230 is the geometric center line of the resonant cavity 230, that is, the central axis M extends along the height direction and passes through the centroid of the cross-section of the resonant cavity 230. Specifically, when the cross-section of the resonant cavity 230 is rectangular (e.g., ... Figure 12 (b) As shown, the centroid of the cross section is the intersection of the diagonals of the rectangle; when the cross section of the resonant cavity 230 is circular, the centroid of the cross section is the center of the circle; when the cross section of the resonant cavity 230 is irregular, the centroid of the irregular shape can be determined by mathematical methods (e.g., integral methods).

[0099] In this embodiment, two frequency tuning rods are inserted into the resonant cavity unit 210 instead of a single frequency tuning rod. This allows each frequency tuning rod 240 to be configured with a smaller cross-sectional area (the specific dimensions can be determined through simulation or actual measurement), reducing the impact of height changes of the frequency tuning rod 240 on the resonant frequency of the resonant cavity unit 210. Simultaneously, the electromagnetic field in the resonant cavity 230 is not concentrated in one area like in a single frequency tuning rod unit, but rather has a relatively dispersed distribution. This improves the linearity of frequency changes in the resonant cavity unit 210, reduces the tuning sensitivity of the filter, and thus lowers the control precision requirements for the motor.

[0100] Figure 13 The simulation effect diagram of the resonant cavity unit 210 (7GHz operating frequency band) provided in this embodiment is shown. Figure 12 In the diagram, the horizontal axis represents the length of the cavity section of the frequency modulation rod 240 (i.e., the length of the frequency modulation rod 240 extending into the resonant cavity 130, in mm), and the vertical axis represents the resonant frequency of the resonant cavity unit 210 (in GHz). Figure 13 It can be seen that within the 1 GHz tuning frequency range, the resonant frequency of the resonant cavity unit 210 changes linearly with the height of the tuning rod 240 (i.e., the frequency change of the resonant cavity unit 210 has good linearity).

[0101] To further describe the positional distribution of the frequency modulation lever 240 in detail, refer to Figure 12 (b) A planar reference system C is established on the cross-section (i.e., the plane perpendicular to the height direction) of the resonant cavity unit 210. The origin O of the reference system C is the location of the central axis M of the resonant cavity unit 210 (i.e., the projection position of the central axis M on the cross-section). The x-axis of the reference system C extends horizontally and the y-axis extends vertically.

[0102] refer to Figure 12 (b) In the cross-section of the resonant cavity unit 210, the projection of the central axis of the resonant cavity 230 is point M, the projection of the central axis of the first tuning rod 244 is point M1, and the projection of the central axis of the second tuning rod 245 is point M2. The distance between the central axis M1 of the first tuning rod 244 and the central axis M of the resonant cavity 230 is D1 (as the first distance), and the distance between the central axis M2 of the second tuning rod 245 and the central axis M of the resonant cavity 230 is D2 (as the second distance). In this embodiment, distances D1 and D2 are the same (i.e., the first tuning rod 244 and the second tuning rod 245 are distributed on the same circumference centered at point M) to simplify the structural design of the resonant cavity unit 210; in other embodiments, distances D1 and D2 may also be different.

[0103] Further, the angle between the line connecting points M and M1 and the positive x-axis is the azimuth angle α1 of the first tuning lever 244 in reference frame C; the angle between the line connecting points M and M2 and the positive x-axis is the azimuth angle α2 of the second tuning lever 245 in reference frame C. In this embodiment, the positive x-axis is used as the reference for the azimuth angle, but this application is not limited to this. In other embodiments, other directions can be used as the reference for the azimuth angle, for example, the positive y-axis.

[0104] In this embodiment, the azimuth angle α1 of the first frequency tuning lever 244 is different from the azimuth angle α2 of the second frequency tuning lever 245, so that the first frequency tuning lever 244 and the second frequency tuning lever 245 are located on different sides of the central axis M. This arrangement allows the first frequency tuning lever 244 and the second frequency tuning lever 245 to be distributed, thereby improving the linearity of the frequency change of the resonant cavity unit 210.

[0105] To further improve the linearity of frequency changes, azimuth angles α1 and α2 are set to have the largest possible difference. For example, the difference between azimuth angles α1 and α2 is 45° to 180°, such as 45°, 60°, 130°, or 180°. Figure 12 In (b), the difference between azimuth angle α1 and azimuth angle α2 is 180°.

[0106] In this embodiment, the distribution positions of the frequency modulation rods 240 in different resonant cavity units 210 can be the same or different. The following description uses units 210a and 210b as examples.

[0107] Example 1: In this example, the positions of the tuning rods 240 are the same in different resonant cavity units 210. (Reference) Figure 14 (a) The resonant cavity unit 210a includes a first frequency modulation rod 244a and a second frequency modulation rod 245a, and the resonant cavity unit 210b includes a first frequency modulation rod 244b and a second frequency modulation rod 245b. The first frequency modulation rod 244a in the resonant cavity unit 210a and the first frequency modulation rod 244b in the resonant cavity unit 210b have the same azimuth angle; the second frequency modulation rod 245a in the resonant cavity unit 210a and the second frequency modulation rod 245b in the resonant cavity unit 210b have the same azimuth angle.

[0108] Example 2: In this example, the positions of the tuning rods 240 differ in different resonant cavity units 210. (Reference) Figure 14 (b) The first tuning rod 244a in the resonant cavity unit 210a and the first tuning rod 244b in the resonant cavity unit 210b have different azimuth angles.

[0109] It should be noted that in this embodiment, the multiple distances D1 corresponding to the multiple resonant cavity units 210 are equal to each other, and the multiple distances D2 corresponding to the multiple resonant cavity units 210 are equal to each other. That is, regardless of Example 1 or Example 2, the distance D1 corresponding to resonant cavity unit 210a is equal to the distance D1 corresponding to resonant cavity unit 210b, and the distance D2 corresponding to resonant cavity unit 210a is equal to the distance D2 corresponding to resonant cavity unit 210b. In this way, during the raising and lowering of the frequency modulation lever 240, the change amplitude of the resonant frequency of each resonant cavity unit 210 is the same.

[0110] Furthermore, within the same resonant cavity unit 210, distances D1 and D2 can be the same or different. When distances D1 and D2 are the same, the structural design of the filter 200 can be simplified. Additionally, in this embodiment, the outer diameter of each tuning rod 240 is greater than 1 mm to improve the manufacturability of the tuning rod 240; and / or, the distance between the tuning rod 240 and the sidewall of the resonant cavity 230 is greater than 1 mm to avoid short circuits.

[0111] This embodiment is an exemplary description of the technical solution of this application, and those skilled in the art can make other modifications.

[0112] For example, in this embodiment, the resonant cavity unit 210 is provided with two frequency tuning rods, but this application is not limited to this. In other embodiments, the resonant cavity unit 210 may be provided with other numbers of frequency tuning rods, for example, three. When the resonant cavity unit 210 has three frequency tuning rods, each frequency tuning rod is located on a different side of the central axis of the resonant cavity 230.

[0113] For example, in this embodiment, the frequency modulation lever 240 is a hybrid medium frequency modulation lever (e.g., Figures 8-10 The frequency modulation lever shown is an example, but this application is not limited thereto. In other embodiments, the frequency modulation lever 240 in the resonant cavity unit 210 may be a single-dielectric frequency modulation lever (e.g., Figure 5 (The frequency tuning lever shown).

[0114] The dual-frequency modulation rod unit scheme provided in this embodiment has been described above. Based on this, a coupling compensation structure can be formed between adjacent resonant cavity units 210 of the filter 200 to improve the performance parameters of the filter 200.

[0115] In tunable filters, the coupling coefficient is a parameter that measures the signal interaction strength between adjacent resonant cavities; the stronger the signal interaction, the larger the coupling coefficient. The coupling coefficient is positively correlated with the filter's operating frequency. That is, as the filter's operating frequency increases, the coupling coefficient increases accordingly; as the filter's operating frequency decreases, the coupling coefficient decreases accordingly. Furthermore, the coupling coefficient is positively correlated with the filter's passband width; that is, the larger the coupling coefficient, the wider the filter's passband width; the smaller the coupling coefficient, the narrower the filter's passband width.

[0116] In some implementations, the filter consists of a single-frequency-tuned rod resonant cavity unit. Figure 5 The filter 100' shown is an example. In this implementation, the passband width of the filter 100' changes significantly when the filter 100' is in different operating positions (i.e., the operating performance of the filter 100' is poor).

[0117] Figure 15 (a) shows the relationship between the operating frequency of filter 100' and the height of the tuning rod. Figure 15 In (a), the horizontal axis represents the length of the cavity section of the tuning lever (in mm), and the vertical axis represents the operating frequency of filter 100' (in GHz). In this example, the tuning frequency range of filter 100' is 600MHz. Points A1, A2, and A3 represent three different operating positions of filter 100'. At point A1, the operating frequency of filter 100' is the initial operating frequency F; at point A2, the operating frequency of filter 100' is F + 300MHz; and at point A3, the operating frequency of filter 100' is F + 600MHz. Specifically, at point A1, the coupling coefficient between resonant cavity units 110' is 0.0584; and at point A3, the coupling coefficient between resonant cavity units 110' is 0.0467. That is, the coupling coefficient changes significantly at different operating positions of filter 100'.

[0118] Figure 15 (b) shows the passband width of filter 100' at each operating position. Curves 1, 2, and 3 represent the spectral curves of filter 100' at points A1, A2, and A3, respectively, and the approximately horizontal segments at the top of curves 1, 2, and 3 represent the passband width of filter 100' at points A1, A2, and A3, respectively.

[0119] from Figure 15 (b) It can be seen that when the operating frequency of filter 100' increases from the initial operating frequency F to F+300MHz, the passband width increases significantly; when the operating frequency of filter 100' increases from the initial operating frequency F by 600MHz, the passband width increases further. Specifically, when the operating frequency of filter 100' increases by 300MHz from the initial frequency, the coupling coefficient increases by 8%, and the passband width of filter 100' increases by 8%; when the operating frequency of filter 100' increases by 600MHz from the initial frequency, the coupling coefficient increases by 20%, and the passband width of filter 100' increases by 20%.

[0120] In other words, in a filter 100' composed of single-frequency modulated bar units, the performance parameters (e.g., passband width) of the filter 100' are closely related to the operating frequency. Ideally, the coupling coefficient should remain essentially constant across the filter's operating frequency range. This ensures that the filter's performance parameters do not deteriorate across the entire operating frequency range (e.g., the passband width remains essentially constant at each operating position).

[0121] The filter 200 provided in this embodiment can improve this situation. (See reference...) Figure 16 In the filter 200 provided in this embodiment, each resonant cavity unit 210 is further provided with a first coupling window 271 and a second coupling window 272 on its sidewall. The resonant cavity unit 210 is coupled to its first adjacent unit through the first coupling window 271 and to its second adjacent unit through the second coupling window 272. In this embodiment, the adjacent unit of the resonant cavity unit 210 can be other resonant cavity units 210 in the filter 200, or it can be a signal input unit 610 for inputting signals to the filter 200, or a signal output unit 620 for receiving the output signals of the filter 200.

[0122] For example, resonant cavity unit 210a is the first resonant cavity unit of filter 200, and it has a first coupling window 271a and a second coupling window 272a. Resonant cavity unit 210a (as the first unit) is coupled to signal input unit 610 (as the first adjacent unit of resonant cavity unit 210a) through the first coupling window 271a, and is coupled to resonant cavity unit 210b (as the second adjacent unit of resonant cavity unit 210a) through the second coupling window 272a;

[0123] The resonant cavity unit 210b is the intermediate resonant cavity unit 210 of the filter 200, and it has a first coupling window 271b and a second coupling window 272b. The resonant cavity unit 210b (as the first unit) is coupled to the resonant cavity unit 210a (as the first adjacent unit of the resonant cavity unit 210b) through the first coupling window 271b (the second coupling window 272a of the resonant cavity unit 210a is combined into one), and is coupled to the resonant cavity unit 210c (as the second adjacent unit of the resonant cavity unit 210b) through the second coupling window 272b.

[0124] The resonant cavity unit 210g is the tail resonant cavity unit of the filter 200, and it has a first coupling window 271g and a second coupling window 272g. The resonant cavity unit 210g (as the first unit) is coupled to the resonant cavity unit 210f (as the first adjacent unit of the resonant cavity unit 210g) through the first coupling window 271g, and is coupled to the signal output unit 620 (as the second adjacent unit of the resonant cavity unit 210g) through the second coupling window 272g.

[0125] Furthermore, in each resonant cavity unit 210, the first tuning lever 244 is disposed in the half-cavity of the resonant cavity 230 (as the first resonant cavity) corresponding to the first coupling window 271, and the second tuning lever 245 is disposed in the half-cavity of the resonant cavity 230 corresponding to the second coupling window 272. The following is in conjunction with... Figure 17 This section explains the meaning of the half-cavity corresponding to the coupling window in resonant cavity 230.

[0126] Figure 17 The cross-section P of the resonant cavity unit 210 is shown. The resonant cavity unit 210 includes a first coupling window 271 and a second coupling window 272. Figure 17 The shaded area in (a) shows the half-cavity corresponding to the first coupling window 271. Figure 17 (b) shows the half-cavity corresponding to the second coupling window 272.

[0127] The meaning of the above-mentioned "half-cavity" is explained using the first coupling window 271 as an example. Figure 17 In the diagram, point M is the projection of the central axis of the resonant cavity unit 210 onto the cross-section P, and point M3 is the projection of the central axis of the first coupling window 271 onto the cross-section P. Line L1 connects points M and M3, and line L2 is perpendicular to line L1 and passes through point M. Figure 17 It can be seen that line L1 divides the resonant cavity 230 into left and right half-cavities. The right half-cavity is the region adjacent to the coupling window; this half-cavity corresponds to the first coupling window 271 of the resonant cavity 230. Figure 17 (a) The shaded area), the first tuning rod 244 of the resonant cavity unit 210 is located in this half-cavity. Similarly, it can be determined that the half-cavity of the resonant cavity 230 corresponding to the second coupling window 272 is the lower half-cavity of the resonant cavity 230. Figure 17 (b) The slanted shaded area), the second tuning rod 245 of the resonant cavity unit 210 is located in this half cavity.

[0128] With the above configuration, a coupling compensation structure can be formed between adjacent resonant cavities 230 of the filter 200. This coupling compensation structure can compensate for the coupling coefficient between adjacent resonant cavity units 210. The following is combined with... Figure 18 Let me introduce it.

[0129] Figure 18 Using resonant cavity units 210a and 210b as examples, two adjacent resonant cavity units of filter 200 are shown. Figure 18 (a) is a front view of the resonant cavity unit 210. Figure 18 (b) is a cross-sectional view of the resonant cavity unit 210. (Reference) Figure 18The resonant cavity units 210a and 210b are coupled through a coupling window 270 (wherein, the coupling window 270 is a window formed by combining coupling windows 272a and 271b). In this way, resonant cavities 230a and 230b can exchange energy through the coupling window 270. The two resonant cavities 230 coupled to each other through the coupling window can be called "two-coupling codfficient".

[0130] The frequency modulation rod 245a is located in the half cavity of the resonant cavity 230a corresponding to the coupling window 270, and the frequency modulation rod 244b is located in the half cavity of the resonant cavity 230b corresponding to the coupling window 270. The frequency modulation rod 245a, the coupling window 270 and the frequency modulation rod 244b together form the "coupling compensation structure" between the resonant cavity units 210a and 210b.

[0131] When the transmission plate 260 drives the tuning rods 240 to descend, the resonant frequencies of the resonant cavity units 210a and 210b decrease, and the coupling coefficient k between the resonant cavity units 210a and 210b decreases. However, as the tuning rods 245a and 244b descend, their lengths within the resonant cavities 230a and 230b increase. Since the window size of the coupling window 270 remains unchanged, the interaction between the tuning rods 245a and 244b increases, thereby mitigating the decrease in the coupling coefficient k (i.e., the "coupling compensation structure" can compensate for the coupling coefficient k).

[0132] Similarly, when the transmission plate 260 drives each tuning rod 240 to rise, the resonant frequency of the resonant cavity units 210a and 210b increases, and the coupling coefficient k between the resonant cavity units 210a and 210b increases. However, as the tuning rods 245a and 244b rise, their lengths inside the resonant cavities 230a and 230b decrease, and the interaction between the tuning rods 245a and 244b weakens, thereby slowing down the increase in the coupling coefficient (i.e., the "coupling compensation structure" can compensate for the coupling coefficient k).

[0133] It should be noted that the principle of compensating for the coupling coefficient k through the "coupling compensation structure" also applies to the case where the resonant cavity unit 210 is coupled to the signal input unit 610 / signal output unit 620. For example, refer to Figure 18 The resonant cavity unit 210a includes a first frequency modulation rod 244a, and the first frequency modulation rod 271a is located in the half cavity of the resonant cavity 230a corresponding to the coupling window 271a. Therefore, the coupling coefficient between the resonant cavity unit 210a and the signal input unit 610 can be compensated.

[0134] Figure 19An exemplary variation curve of the coupling coefficient k in this embodiment is shown. Figure 19 In the diagram, the horizontal axis represents the length of the 240mm cavity section of the frequency modulation rod (unit: mm), and the vertical axis represents the coupling coefficient k. From... Figure 19 It can be seen that by setting the "coupling compensation structure", within the tuning frequency range of filter 200 ( Figure 19 The example shown is for 600MHz), and the coupling coefficient k between adjacent resonant cavity units 210 remains basically unchanged.

[0135] Figure 20 The passband width of the filter 200 at different operating positions in this embodiment is shown. Figure 20 In the diagram, curve 1 represents the spectrum of filter 200 at its initial operating position (operating frequency F), and curve 2 represents the spectrum of filter 200 at another operating position (operating frequency F+600MHz). The approximately horizontal segments at the top of curves 1 and 2 represent the passband width of filter 200 at operating frequencies F and F+600MHz, respectively. Figure 20 It can be seen that when the operating frequency of filter 200 increases from the initial frequency F to F+600MHz, the passband width of filter 200 remains basically unchanged. That is, by setting the "coupling compensation structure", filter 200 has a basically the same passband width at each operating position, and filter 200 has excellent performance parameters.

[0136] The arrangement of the first tuning lever 244 and the second tuning lever 245 in the resonant cavity 230 is described above (for example, the above description of...). Figure 12 , Figure 14 The description of the first and second frequency modulation rods 244 and 245 in the resonant cavity 230 will not be repeated here. Based on this, those skilled in the art can determine the actual positions of the first and second frequency modulation rods 244 and 245 in the resonant cavity 230 according to specific needs (e.g., by simulation). For example, the distance D1 (i.e., the distance between the first frequency modulation rod 244 and the central axis M of the resonant cavity 230) can be equal to the distance D2 (i.e., the distance between the second frequency modulation rod 245 and the central axis M of the resonant cavity 230), and the azimuth angle α1 of the first frequency modulation rod 244 and the azimuth angle α2 of the second frequency modulation rod 245 can be adjusted accordingly to simplify the design process of the filter 200. In other examples, the distances D1 and D2 may also be different.

[0137] In the above embodiments, the resonant cavity units 210 in the filter 200 are arranged in a linear topology, that is, each resonant cavity unit 210 has two adjacent units. However, this application is not limited to this. In other embodiments, the resonant cavity units 210 in the filter 200 can be arranged in other forms, such as CT topology (each resonant cavity unit 210 has a maximum of 3 adjacent units) and CQ topology (each resonant cavity unit 210 has a maximum of 4 adjacent units). The CT topology is described below as an example.

[0138] Figure 21 An exemplary structural diagram (top view) of the filter 300 provided in this embodiment is shown. The filter 300 includes multiple resonant cavity units, namely resonant cavity units 310a to 310g. The resonant cavity units 310a to 310g are arranged in a CT topology. Some resonant cavity units (e.g., unit 310a, unit 310c) have three adjacent units.

[0139] The resonant cavity unit 310a is described as an example. The resonant cavity unit 310a includes coupling windows 371a, 372a, and 373a. The resonant cavity unit 310a (as the first unit) is coupled to the signal input unit 610 (as the first adjacent unit of the resonant cavity unit 310a), the resonant cavity unit 310b (as the second adjacent unit of the resonant cavity unit 310a), and the resonant cavity unit 310c (as the third adjacent unit of the resonant cavity unit 310a) through the first coupling window 371a, the second coupling window 372a, and the third coupling window 373a, respectively.

[0140] The resonant cavity unit 310a further includes a first frequency modulation rod 344a and a second frequency modulation rod 345a. The first frequency modulation rod 344a is located in the half-cavity of the resonant cavity 330a corresponding to the first coupling window 371a; the second frequency modulation rod 345a is located in the half-cavity of the resonant cavity 330a corresponding to the second coupling window 372a, and also in the half-cavity of the resonant cavity 330a corresponding to the third coupling window 373a.

[0141] The resonant cavity unit 310b includes a first tuning bar 344b, which is located in the half-cavity of the resonant cavity 330b corresponding to the first coupling window 371b (which is combined with the second coupling window 372a). Therefore, the tuning bar 345a, the coupling window 372a, and the tuning bar 344b together form a "coupling compensation structure" for compensating the coupling coefficient between the resonant cavity units 310a and 310b.

[0142] The resonant cavity unit 310c includes a first frequency modulation rod 344c, which is located in the half-cavity of the resonant cavity 330c corresponding to the first coupling window 371c (which is combined with the third coupling window 373a). Therefore, the frequency modulation rod 345a, the coupling window 373a, and the frequency modulation rod 344c together form a "coupling compensation structure" for compensating the coupling coefficient between the resonant cavity units 310a and 310c.

[0143] Figure 21 In the example shown, each resonant cavity unit 310 has two frequency tuning rods, which simplifies the filter's structural design. However, this application is not limited to this. In other examples, when the resonant cavity unit 310 has three or more adjacent units, the resonant cavity unit may include three frequency tuning rods. The CT topology will still be used as an example for explanation.

[0144] Figure 22 A structural diagram (top view) of a filter 400 provided in another embodiment of this application is shown. This embodiment is similar to... Figure 21 The difference in the illustrated embodiment is that the resonant cavity unit 410, which has three adjacent units, has three tuning rods.

[0145] The resonant cavity unit 410a will still be used as an example for explanation. The resonant cavity unit 410a includes coupling windows 471a, 472a, and 473a. The resonant cavity unit 410a (as the first unit) is coupled to the signal input unit 610 (as the first adjacent unit of the resonant cavity unit 410a), the resonant cavity unit 410b (as the second adjacent unit of the resonant cavity unit 410a), and the resonant cavity unit 410c (as the third adjacent unit of the resonant cavity unit 410a) through the first coupling window 471a, the second coupling window 472a, and the third coupling window 473a, respectively.

[0146] The resonant cavity unit 410a further includes a first frequency modulation rod 444a, a second frequency modulation rod 445a, and a third frequency modulation rod 446a. The first frequency modulation rod 444a is located in the half-cavity of the resonant cavity 430a corresponding to the first coupling window 471a; the second frequency modulation rod 445a is located in the half-cavity of the resonant cavity 430a corresponding to the second coupling window 472a; and the third frequency modulation rod 446a is located in the half-cavity of the resonant cavity 430a corresponding to the third coupling window 473a.

[0147] The resonant cavity unit 410b includes a first tuning bar 444b, which is located in the half-cavity of the resonant cavity 430b corresponding to the first coupling window 471b (which is combined with the second coupling window 472a). Therefore, the tuning bar 445a, the coupling window 472a, and the tuning bar 444b together form a "coupling compensation structure" for compensating the coupling coefficient between the resonant cavity units 410a and 410b.

[0148] The resonant cavity unit 410c includes a first frequency modulation rod 444c, which is located in the half-cavity of the resonant cavity 430c corresponding to the first coupling window 471c (which is combined with the third coupling window 473a). Therefore, the frequency modulation rod 445a, the coupling window 473a, and the frequency modulation rod 444c together form a "coupling compensation structure" for compensating the coupling coefficient between the resonant cavity units 410a and 410c.

[0149] The above embodiments are exemplary descriptions of the technical solutions of this application, and those skilled in the art can make other modifications.

[0150] For example, in the above embodiments, the filter is a rectangular waveguide filter. In other embodiments, the filter may also be a coaxial, TE, or TM mode cavity filter, etc., and this application does not limit it.

[0151] For example, in the above embodiments, the filter is applied to microwave communication scenarios. In other embodiments, the filter can also be used in cellular network and other communication scenarios;

[0152] For example, in the above embodiments, the tuning lever can be raised and lowered relative to the resonant cavity to adjust the operating frequency of the filter (i.e., in the above embodiments, the filter is an adjustable filter). In other embodiments, the filter can also be a non-adjustable filter (i.e., a fixed-band filter).

[0153] In summary, this application provides a filter having "hybrid dielectric tuning rod" resonant cavity units, where each resonant cavity unit has tuning rod 1 divided into N (N is 2 or 3). This embodiment can improve the tuning frequency range of the filter, reduce filter signal leakage, improve the linearity of filter operating frequency changes, and reduce the control precision requirements of motor components; adjacent resonant cavity units have a "coupling compensation structure" so that the filter's performance indicators (e.g., passband width) do not deteriorate over an ultra-wide tuning frequency range.

[0154] For example, the filter provided in this application embodiment has a tuning frequency range of over 600MHz, which is more than 200% higher than the original method. This can significantly reduce product coding in microwave communication systems (e.g., unifying filter product coding in the same frequency band) and expand the application range of the filter. At the same time, it reduces the development and manufacturing costs of the filter, as well as the production, operation, and maintenance costs of the microwave communication system.

[0155] Compared to other filters, the filter provided in this application embodiment has a "hybrid dielectric tuning bar" and a "coupling compensation structure," thereby achieving improved performance parameters over a wider tuning frequency range (e.g., having substantially the same passband width at each operating position). A comparison is made below with filters provided in other embodiments.

[0156] Figure 23 One implementation method is shown. Specifically, Figure 23 This invention relates to an H-plane dielectric tunable waveguide filter, comprising a rectangular waveguide; a coupling structure is disposed within the rectangular waveguide, the coupling structure dividing the inner cavity of the rectangular waveguide into several resonant cavities; at least one tunable element is disposed within each resonant cavity; several through holes are disposed on the H-plane of the rectangular waveguide, one end of the tunable element extends into the rectangular waveguide through the through holes, and the other end is connected to a driving mechanism. In this design, compared to tunable elements disposed on the E-plane with the same resonant cavity size, it has a larger dielectric travel distance and a wider tuning range; within the same tuning range, the travel distance of the tunable element can be greater, and it has lower tuning sensitivity.

[0157] Compared to Figure 23 As shown, the filter in this embodiment has a hybrid dielectric tuning bar and a coupling compensation structure, which is more conducive to achieving improved performance parameters over a wider tuning frequency range. Specifically:

[0158] (1) In this embodiment, the portion of the tuning rod located inside the resonant cavity has a larger relative permittivity Er, while the portion located outside the resonant cavity has a smaller relative permittivity Er. Simultaneously, the thickness of the top wall of the resonant cavity is set such that the signal in the resonant cavity will not leak through the tuning hole, thereby enabling the filter to have a wider tuning frequency range and keeping signal leakage in the resonant cavity at a low level.

[0159] (2) In this embodiment of the application, the frequency tuning rod in the resonant cavity unit is divided into N (N is 2 or 3), and each frequency tuning rod is located on one side of the central axis of the resonant cavity. In this way, the frequency change linearity of the resonant cavity unit can be improved, the tuning sensitivity of the filter can be reduced, and the control accuracy requirements of the motor assembly can be reduced.

[0160] (3) In the embodiments of this application, by dividing the frequency modulation rod into N (N is 2 or 3), a "coupling compensation structure" can also be formed between adjacent resonant cavity units. The coupling compensation structure can compensate for the coupling coefficient between adjacent resonant cavity units, between the first resonant cavity unit and the signal input unit, and between the tail resonant cavity and the signal output unit. In this way, when the filter is located in different working positions, its coupling coefficient remains basically unchanged, thereby making the filter have basically the same passband width at different working positions, and the filter performance parameters are excellent.

[0161] In the above description of this embodiment, unless otherwise stated, " / " means "or". For example, A / B can identify A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, B exists alone, and A and B exist simultaneously.

Claims

1. A filter, characterized in that, It includes at least one resonant cavity unit, and each of the resonant cavity units includes: A housing, wherein a resonant cavity is formed inside the housing, and a tuning hole is provided on the top wall of the resonant cavity; A tuning rod is inserted into the resonant cavity through the tuning hole. The tuning rod can move up and down relative to the resonant cavity along the height direction of the resonant cavity unit to adjust the resonant frequency of the resonant cavity unit. The frequency tuning rod includes a first dielectric segment and a second dielectric segment connected sequentially from top to bottom. During the lifting and lowering movement of the frequency tuning rod, the second dielectric segment is at least partially located inside the resonant cavity. The relative permittivity Er2 of the second dielectric segment is greater than the relative permittivity Er1 of the first dielectric segment. Specifically, when the frequency tuning rod is at the upper limit of its lifting stroke, the interface between the first medium segment and the second medium segment is not higher than the upper surface of the top wall; when the frequency tuning rod is at the lower limit of its lifting stroke, the interface between the first medium segment and the second medium segment is not lower than the lower surface of the top wall.

2. The filter according to claim 1, characterized in that, 1 < Er1 ≤ 3, Er2 ≥ 5.

3. The filter according to claim 1, characterized in that, The at least one resonant cavity unit includes a first unit, the resonant cavity of the first unit is a first resonant cavity, and the frequency tuning rod of the first unit includes a first frequency tuning rod and a second frequency tuning rod; The first tuning bar and the second tuning bar are located on different sides of the central axis of the first resonant cavity.

4. The filter according to claim 3, characterized in that, In a planar reference frame perpendicular to the central axis of the resonant cavity and with the location of the central axis of the resonant cavity as the origin, the difference between the azimuth angle of the first tuning rod and the azimuth angle of the second tuning rod is 45°~180°.

5. The filter according to claim 3, characterized in that, The at least one resonant cavity unit includes a plurality of adjacent first units; each first unit has a first coupling window and a second coupling window on its sidewall; the first unit is coupled to a first adjacent unit of the first unit through the first coupling window, and coupled to a second adjacent unit of the first unit through the second coupling window; The first frequency tuning rod is located in the half-cavity of the first resonant cavity corresponding to the first coupling window, and the second frequency tuning rod is located in the half-cavity of the first resonant cavity corresponding to the second coupling window.

6. The filter according to claim 5, characterized in that, A third coupling window is also provided on the side wall of the first unit, and the first unit is coupled to the third adjacent unit of the first unit through the third coupling window; The second tuning rod is located in the half-cavity of the first resonant cavity corresponding to the second coupling window, and also in the half-cavity of the first resonant cavity corresponding to the third coupling window.

7. The filter according to claim 5, characterized in that, A third coupling window is also provided on the side wall of the first unit, and the first unit is coupled to the third adjacent unit of the first unit through the third coupling window; The first unit's tuning rod also includes a third tuning rod, wherein the third tuning rod is located in the half-cavity of the first resonant cavity corresponding to the third coupling window.

8. The filter according to claim 6, characterized in that, The adjacent units of the first unit are one of the following: other resonant cavity units in the at least one resonant cavity unit; a signal input unit that inputs a signal to the filter; and a signal output unit that receives the output signal of the filter.

9. The filter according to claim 3 or 5, characterized in that, The distance between the central axis of the first frequency tuning rod and the central axis of the first resonant cavity is the first distance, and the distance between the central axis of the second frequency tuning rod and the central axis of the first resonant cavity is the second distance; The at least one resonant cavity unit includes a plurality of first units arranged adjacent to each other, wherein the plurality of first distances corresponding to the plurality of first units are equal to each other, and the plurality of second distances corresponding to the plurality of first units are equal to each other.

10. The filter according to claim 9, characterized in that, The first distance is equal to the second distance.

11. The filter according to claim 5, characterized in that, The plurality of first units are arranged in a linear topology, a CQ topology, or a CT topology.

12. The filter according to claim 1, characterized in that, The outer diameter of the tuning rod is greater than or equal to 1 mm; and / or the distance between the tuning rod and the sidewall of the resonant cavity is greater than or equal to 1 mm.

Images