Waveguide Filters

Abstract

To provide a waveguide filter, in which properties of a particular passband are enhanced by implementing coupling by using a resonator tunnel that connects resonator posts.SOLUTION: A waveguide filter includes: a filter housing provided with a plurality of resonance blocks; a plurality of resonators configured by resonator posts respectively formed on the resonance blocks provided on the filter housing; and a resonator tunnel configured in the filter housing so as to connect two resonator posts each other to couple the two resonator posts, among the plurality of resonator posts. The resonator tunnel includes a horizontal resonator tunnel configured to penetrate inside the filter housing in a width direction or a longitudinal direction to connect at least two resonator posts to each other among the plurality of resonator posts. A coupling quantity changes depending on a depth of the horizontal resonator tunnel.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a waveguide filter for an antenna, and more particularly to a waveguide filter including a resonator and using cross-coupling. [Background technology]

[0002] Recently, as the number of types of wireless communication services increases, the frequency environment becomes more complex. Since the frequencies for wireless communication are limited, it is necessary to make wireless communication channels as close as possible to effectively utilize frequency resources.

[0003] However, since signal interference occurs in an environment where various wireless communication services are provided, an antenna includes a bandpass filter for a specific band in order to minimize signal interference between adjacent frequency resources.

[0004] Generally, in order to improve the attenuation characteristics of a bandpass filter, it is necessary to apply a transmission zero (hereinafter, a notch), which is realized by applying cross coupling between non-adjacent resonant elements.

[0005] Among RF filters, ceramic waveguide filters include a resonator for adjusting notches in a dielectric block covered with a conductive film. The resonator is designed to give resonance characteristics to electromagnetic waves and limit specific frequencies.

[0006] In this case, when cross-coupling is performed across an even number of resonators, symmetrical notches in the passband are generated, whereas when cross-coupling is performed across an odd number of resonators, one notch is generally generated on the left or right side depending on the type of coupling.

[0007] The realization of such a notch in a communication filter needs to be realized in a very diverse manner depending on the performance of the communication system, but the performance is limited in order to realize a filter suited to the characteristics of the communication system.

[0008] This requires that the filters be set differently for different communication systems so that notches on the left and right of a particular passband can be achieved at the antenna.

[0009] In particular, when realizing notches on the left and right sides of the passband with one cross coupling, if the left side is asymmetrical and strong coupling is required and the right side is weak coupling, two cross coupling structures have to be used. However, realizing such two cross couplings imposes many constraints on the filter design, and is particularly problematic in ceramic filter structures in which it is difficult to insert additional structures to realize cross coupling inside the filter.

[0010] Also, to achieve two notches on the left or right side of the passband to meet the desired performance, two cross-couplings through an odd number of resonators must be realized, which imposes a number of design constraints. Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made to solve the above technical problems, and has an object to provide a waveguide filter in which the characteristics of a specific passband are enhanced by achieving coupling via a resonator tunnel connecting resonator posts.

[0012] The technical problems of the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0013] One embodiment of a waveguide filter according to the present invention includes a filter housing having a plurality of resonator blocks, a plurality of resonators each having a resonator post formed on each of the resonator blocks provided in the filter housing, and a resonator tunnel provided in the filter housing to interconnect at least two of the plurality of resonator posts, the resonator posts being provided on one side and the other side of the filter housing in an inverted manner, for coupling.

[0014] Here, the two resonator posts connected by the resonator tunnel are arranged in an inverted manner to enable adjacent coupling.

[0015] In addition, the two resonator posts connected by the resonator tunnel are arranged in an inverted manner to enable cross-coupling.

[0016] The resonator tunnel may include a horizontal resonator tunnel that penetrates the interior of the filter housing in a width direction or a length direction to interconnect the at least two resonator posts.

[0017] The resonator tunnel may further include a resonator vertical tunnel that is provided to penetrate the filter housing from above to below and is connected to the resonator horizontal tunnel.

[0018] The resonator tunnel may further include a resonator extension tunnel extending from the resonator horizontal tunnel and opening toward one or the other surface of the filter housing.

[0019] The resonator horizontal tunnel is formed to be inclined in the width direction of the filter housing.

[0020] The resonator tunnels are formed inside the filter housing in mirror symmetry with respect to each other with respect to the center of the two resonator posts.

[0021] In addition, a tuning resonator post for tuning adjustment is further provided on the opposing surface of the filter housing of either one of the two resonator posts.

[0022] The plurality of resonator blocks may be divided by a plurality of partition walls or a plurality of partition slots formed between the respective resonator blocks.

[0023] The resonator tunnel is provided so as to be interconnected to cross-couple two adjacent resonator posts in a width direction of the filter housing.

[0024] The resonator tunnel is provided so as to be interconnected to adjacently couple two resonator posts adjacent to each other in the longitudinal direction of the filter housing.

[0025] Also, a notch due to inductive coupling is formed by the resonator tunnel, and the formation position of the notch is adjusted according to the shape and size of the resonator tunnel. Effect of the Invention

[0026] According to an embodiment of the waveguide filter according to the present invention, the following various effects can be achieved.

[0027] In other words, the present invention realizes coupling by connecting a plurality of resonator posts via resonator tunnels, thereby realizing characteristic notches on both sides of a specific passband, making it possible to easily design a filter and improve the characteristics of the filter.

[0028] Furthermore, the present invention can set up cross-coupling or adjacent coupling in a limited space using resonator horizontal tunneling.

[0029] In addition, the present invention can change the filter characteristics by changing the position or shape of the resonator horizontal tunnel and the resonator vertical tunnel to change the characteristics of the cross-coupling or adjacent coupling.

[0030] The present invention also allows for the creation of cuts to the left or right of the passband with desired characteristics by changing the position or shape of the resonator horizontal tunnel and the resonator vertical tunnel.

[0031] Furthermore, the present invention allows for easy filter design regardless of the type of dielectric used in waveguide filters that use ceramic or air as the dielectric.

[0032] In addition, the present invention provides a resonator vertical tunnel penetrating the filter housing in the thickness direction or a resonator horizontal tunnel penetrating the filter housing in the width direction, thereby achieving various filter performances depending on the position and shape.

[0033] The present invention also simplifies the filter complexity, reducing manufacturing costs and increasing manufacturability. [Brief description of the drawings]

[0034] [Figure 1A] 1 is a perspective view of one surface of a waveguide filter according to an embodiment of the present invention; [Figure 1B] FIG. 2 is a perspective view of the other surface of a waveguide filter according to an embodiment of the present invention. [Figure 2A] FIG. 1B is a plan view of one surface of FIG. 1A. [Figure 2B] FIG. 1C is a plan view of the other surface of FIG. 1B. [Figure 3A] FIG. 2B is a cross-sectional view taken along line DD in FIG. 2A. [Figure 3B] FIG. 2B is a cutaway perspective view taken along line DD in FIG. 2A. [Figure 4] 1 is a graph showing a plot (PLOT) of frequency characteristics of a waveguide filter according to one embodiment of the present invention. [Diagram 5]FIG. 2 is a schematic diagram illustrating the change in frequency characteristics according to the depth and width of a resonator tunnel and the distance from a partition slot in the configuration of a waveguide filter according to an embodiment of the present invention. [Figure 6] 6 is a graph showing a plot (PLOT) of frequency characteristics according to changes in the depth of the resonator tunnel, among the elements of FIG. 5. [Figure 7A] 1A to 1C are schematic diagrams showing various application examples of a resonator tunnel in a waveguide filter according to an embodiment of the present invention; [Figure 7B] 1A to 1C are schematic diagrams showing various application examples of a resonator tunnel in a waveguide filter according to an embodiment of the present invention; [Figure 7C] 1A to 1C are schematic diagrams showing various application examples of a resonator tunnel in a waveguide filter according to an embodiment of the present invention; [Figure 8] FIG. 13 is a schematic diagram showing a resonator tunnel configured to achieve side-by-side coupling according to another embodiment of the present invention; [Figure 9] 9 is a graph showing a plot (PLOT) of frequency characteristics of the waveguide filter according to the other embodiment of FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The advantages and features of the present invention, as well as the methods for achieving them, will become clear from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be realized in various different forms. The embodiments are provided solely to complete the disclosure of the present invention and to fully inform those skilled in the art of the present invention of the scope of the invention, and the present invention is defined solely by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

[0036] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of a waveguide filter according to the present invention will be described in detail with reference to the accompanying drawings.

[0037] 1A and 1B are perspective views of one and the other sides of a waveguide filter according to one embodiment of the present invention, FIGS. 2A and 2B are plan views of the one and the other sides of FIGS. 1A and 1B, and FIGS. 3A and 3B are a cross-sectional view and a cutaway perspective view taken along line DD in FIG. 2.

[0038] In particular, FIG. 1B shows the filter housing 99 of FIG. 1A rotated 180 degrees about axis "C."

[0039] A communication antenna includes an RF filter (Radio Frequency Filter) for filtering a signal of a specific passband. Depending on the characteristics, a cavity filter, a waveguide filter, etc. are used as the RF filter. Hereinafter, one embodiment and another embodiment of the present invention will be described focusing on a waveguide filter provided in an antenna.

[0040] The waveguide filter 100 generally includes at least four (i.e., four or more) resonant blocks. For example, one filter housing 99 may include four to twenty resonant blocks.

[0041] In one embodiment of the present invention, as shown in FIGS. 1A to 3B, a case will be described as an example in which one filter housing 99 is provided with ten resonance blocks 11 to 20. In the embodiment of the present invention, as shown in FIG.

[0042] One embodiment of a waveguide filter 100 according to the present invention may include a filter housing 99 in the shape of a rectangular parallelepiped having a substantially predetermined thickness and a predetermined length, as shown in FIGS. 1A-4.

[0043] In the filter housing 99, as described above, the ten resonance blocks 11 to 20 can be separated from each other by the partition walls 51 to 60 or the partition slots 71 and 72.

[0044] The resonance blocks 11 to 20 partitioned by the partitions 51 to 60 or the partition slots 71, 72 do not necessarily need to be completely partitioned physically, but rather refer to partitions that allow a specific resonance block to be distinguished from adjacent resonance blocks in appearance.

[0045] Here, the inside of each of the resonator blocks 11 to 20 is filled with a dielectric material, and the dielectric material can be ceramic or air.

[0046] However, the dielectric material is not necessarily limited to ceramic or air, and other dielectric materials can of course be used.

[0047] The multiple resonance blocks 11-20 each operate as one resonator 1-10, and a waveguide filter 100 made up of the ten resonators 1-10 can be formed via the ten resonance blocks 11-20.

[0048] On the other hand, the resonance blocks 11 to 20 are provided with resonator posts 31 to 40. In the following, the resonance blocks 11 to 20 are ordered clockwise from the upper left end in Fig. 1A and Fig. 1B as the first resonance block 11, the second resonance block 12, ..., the tenth resonance block 20, and the resonator posts 31 to 40 provided on the resonance blocks 11 to 20 corresponding to each order are also ordered as the first resonator post 31, the second resonator post 32, ..., the tenth resonator post 40. Unless otherwise specified, the above-mentioned partitions 51 to 60 can also be ordered in the same way.

[0049] The resonator posts 31 to 40 are provided on the upper end surfaces or the lower end surfaces of the resonance blocks 11 to 20. For example, when the first resonator post 31 is provided on one surface of the first resonance block 11, The resonator posts 32 to 40 are also preferably provided in common on one surface of each of the resonator blocks 12 to 20 .

[0050] Here, the meaning of "being provided" with the resonator posts 31 to 40 must be defined differently depending on the type of dielectric material filled in the filter housing 99.

[0051] For example, when air is used as the dielectric so as to have the dielectric constant of air, the resonator posts 31-40 are provided by deleting or removing the corresponding portions of the filter housing 99, and therefore the meaning of "provided" in this case is equivalent to the meaning of "formed".

[0052] As another example, the word "provided" in this case is understood to have an inherent meaning in that the dielectric, except for air, fills and fixes the relevant portion of the filter housing 99 in a physically hardened state.

[0053] On the other hand, as in one embodiment of the present invention, the second resonator post 32 ′ and the ninth resonator post 39 , which require cross-coupling, are formed on different sides of the filter housing 99 .

[0054] More specifically, the first resonator post 31 and the third to tenth resonator posts 33 to 40, excluding the second resonator post 32, are formed on one side of the filter housing 99, and only the second resonator post 32 is formed on the bottom surface of the filter housing 99.

[0055] On the opposite surface of the filter housing 99 opposite to where the second resonator post 32 is located, a tuning resonator post 32' is formed on the same surface as the ninth resonator post 39. The second resonator post 32 and the tuning resonator post 32' may have a structure in which they are only opposed to each other at their positions and are not interconnected.

[0056] More specifically, the second resonator post 32 is provided in the form of a groove cut from one surface, one of the surfaces of the filter housing 99, opposite the surface on which the other resonator posts 31, 33-40 are formed, toward one surface by a predetermined depth (hereinafter referred to as the "first depth"), and the tuning resonator post 32' is provided in the form of a groove cut from one surface, one of the surfaces of the filter housing 99, opposite the surface on which the other resonator posts 31, 33-40 are formed, toward the other surface by a predetermined depth (hereinafter referred to as the "second depth").

[0057] Here, the second depth of the tuning resonator post 32' is formed relatively smaller than the first depth of the second resonator post 32 as long as tuning design using a tuning screw (not shown) is possible.

[0058] At this time, the sum of the first depth of the second resonator post 32 and the second depth of the tuning resonator post 32' must not penetrate the filter housing 99 as described above, so it is preferable that it is formed to be smaller than the length between one side and the other side of the filter housing 99 (i.e., the thickness of the filter housing 99).

[0059] The first to tenth resonance blocks 11 to 20 are coupled to the first to tenth resonator posts 31 to 40 and operate as one resonator, respectively, thereby forming the first to tenth resonators (circled numbers 1 to 10 in the figure).

[0060] As described above, partition walls 51-60 or partition slots 71, 72 are formed between each of the resonance blocks 11-20, and the size and resonance characteristics of each resonance block 11-20 can be varied depending on the size (width, length) and position of the partition walls 51-60 or partition slots 71, 72.

[0061] For example, the second resonator block 12 is separated from the first resonator block 11 and the third resonator block 13 located on the left and right sides by the first partition 51 and the second partition 52, and is separated from the ninth resonator block 19 adjacent to it in the width direction by the first partition slot 71 and the second partition slot 72.

[0062] Meanwhile, the waveguide filter 100 may further include an input post 21 to which a signal is input and an output post 22 from which a signal is output.

[0063] The input post 21 and the output post 22 are formed in different resonating blocks (more specifically, the input post 21 is provided in the eighth resonating block 18, and the output post 22 is provided in the seventh resonating block 17), and the input post 21 and the output post 22 are each provided on one side of the resonating blocks 11 to 20. In one embodiment of the present invention, it is assumed that the input post 21 and the output post 22 are formed on the other side of the filter housing 99.

[0064] On the other hand, the waveguide filter 100 may further include a resonator horizontal tunnel 81 and a resonator vertical tunnel 82 that realize cross-coupling between specific resonator blocks (in this embodiment, the second resonator block 12 and the ninth resonator block 19).

[0065] Hereinafter, if necessary, the resonator horizontal tunnel 81 and the resonator vertical tunnel 82 will be generally defined as the "resonator tunnel" and will be described with reference to the reference numeral 80.

[0066] 1A to 3B, the resonator tunnel 80 is formed penetrating the filter housing 99 in the width direction and serves to interconnect the second resonator post 32 and the ninth resonator post 39 for achieving cross-coupling. The resonator tunnel 80 reduces the physical distance between the second resonator post 32 and the ninth resonator post 39.

[0067] More specifically, as shown in FIG. 5 , when the thickness direction of the filter housing 99 is defined as the "vertical direction" and the width direction of the filter housing 99 is defined as the "horizontal direction", the resonator tunnel 80 can include a resonator horizontal tunnel 81 that horizontally connects the second resonator post 32 and the ninth resonator post 39, and a resonator vertical tunnel 82 that vertically connects one side and the back side of the filter housing 99 in the middle of the resonator horizontal tunnel 81.

[0068] In addition, the resonator tunnel 80 may further include a resonator extension tunnel 83 extending from the resonator horizontal tunnel 81 toward one surface or the other surface of the filter housing 99, as shown in FIGS. 3A and 3B.

[0069] The resonator horizontal tunnel 81 and the resonator extension tunnel 83 are each formed with the same width by removing a part of the filter housing 99. For convenience of explanation, the distance from the top or bottom surface of the filter housing 99 to the bottom surface of the resonator horizontal tunnel 81 is defined as the "depth of the resonator tunnel 80". The depth of the resonator tunnel 80 is formed to be equal to or smaller than the depth of the second resonator post 32 or the ninth resonator post 39.

[0070] In addition, the resonator horizontal tunnel 81 or the resonator extension tunnel 83 will be described with the width perpendicular to the extension direction defined as the "width of the resonator tunnel 80."

[0071] By utilizing such an interconnection structure between the second resonator post 32 and the ninth resonator post 39 by the resonator tunnel 80, the two resonators 32, 39 can be cross-coupled.

[0072] From a technical standpoint, a resonator post (e.g., the ninth resonator post 39) formed to open toward the upper surface of the filter housing 99 and a resonator post (e.g., the second resonator post 32) formed to open toward the lower surface of the filter housing 99 realize capacitive coupling (C-coupling) as a topological inversion effect. However, in the waveguide filter according to one embodiment of the present invention, the mutually inverted resonator posts (the ninth resonator post 99 and the second resonator post 32) are connected via the resonator tunnel 80, thereby realizing inductive coupling (L-coupling), which is a technical feature.

[0073] Here, in one embodiment of the present invention, a structure in which the resonator tunnel 80 interconnects the second resonator post 32 and the ninth resonator post 39 is illustrated, but the resonator posts to be interconnected may vary depending on the position design of the cross-coupling to be realized.

[0074] That is, although not shown, a resonator tunnel 80 can be formed that enables mutual coupling between the first resonator post 31 and the tenth resonator post 40 formed on its opposite side, the third resonator post 33 and the eighth resonator post 38 formed on its opposite side, etc.

[0075] In addition, in one embodiment of the present invention, the resonator tunnel 80 is described as a structure that interconnects the second resonator post 32 and the ninth resonator post 39 to provide cross-coupling. However, as will be described later with reference to FIG. 8, the interconnected resonator posts can also be provided with adjacent coupling between adjacent resonator posts depending on the type of coupling to be achieved.

[0076] Here, "adjacent coupling" refers to coupling between multiple resonator posts arranged in sequence according to the signal flow from the input post 21 to the output post 22, and coupling across at least one or more resonator posts can be defined as "cross coupling."

[0077] Of the configurations of the resonator tunnels 80, the resonator horizontal tunnel 81 is defined as a widthwise connecting section of the filter housing 99 having a width and depth (H1 or less) smaller than the inner diameters of the ninth resonator post 39 and the second resonator post 32, as shown in FIG. 3A.

[0078] However, the resonator horizontal tunnel 81 is formed in a portion adjacent to the second resonator post 32 and the ninth resonator post 39 by a resonator extension tunnel 83, which opens onto one side of the filter housing 99 and onto the other side of the filter housing 99, respectively.

[0079] Here, when the thickness of filter housing 99 is defined as "H", the depth H1 of resonator horizontal tunnel 81 is defined as the thickness H of filter housing 99 minus the thickness H2 from the other side of filter housing 99 to the bottom surface of resonator horizontal tunnel 81, or the distance H3 between the bottom surface of ninth resonator post 39 and the bottom surface of resonator horizontal tunnel 81.

[0080] Meanwhile, the resonator vertical tunnel 82 is provided in a spatial form so as to penetrate vertically (in the thickness direction) through the lower surface of the filter housing 99 adjacent to the second resonator post 32 and to be connected to the internal resonator horizontal tunnel 81, and also penetrates vertically (in the thickness direction) through the upper surface of the filter housing 99 adjacent to the ninth resonator post 39 and to be connected to the internal resonator horizontal tunnel 81.

[0081] The radius on one side and the radius on the other side of the resonator vertical tunnel 82 are formed to be shared with the adjacent resonator extension tunnel 83 in the horizontal direction (width direction), so that a cylindrical space is formed penetrating the filter housing 99 in the vertical direction as a whole.

[0082] In addition, although the resonator vertical tunnel 82 is described as being in the form of a hole having a circular cross section in one embodiment of the present invention, it may of course be provided to have either a rectangular or polygonal cross section, and its size, width and depth may be varied to adjust the amount of inductive coupling, which will be described later.

[0083] On the other hand, in an embodiment in which the resonator extension tunnel 83 is not provided (see the application example of FIG. 7A described later), the resonator vertical tunnel 82 is provided in a form that connects one side of the filter housing 99 to the other side and also penetrates and connects to the resonator horizontal tunnel 81 formed therein.

[0084] Such a resonator vertical tunnel 82 is not necessarily a required component of the resonator tunnel 80, and it is of course possible to realize an embodiment having only the resonator horizontal tunnel 81 (see the application example of FIG. 7C described later).

[0085] As shown in Figures 1A to 2B, when the filter housing 99 is rotated 180 degrees based on the drawing reference character "C", the resonator tunnel 80 is formed in a mirror-symmetric shape with respect to the second resonator post 32 and the ninth resonator post 39, respectively.

[0086] That is, as shown in Figures 3A to 3B, the second resonator post 32 and the ninth resonator post 39 are designed to have different depths, but it is preferable that the resonator tunnel 80 is provided so as to be perfectly mirror symmetric in the diagonal direction about an arbitrary reference line that crosses vertically through the middle between the second resonator post 32 and the ninth resonator post 39.

[0087] Meanwhile, a tuning resonator post 32' to which a tuning screw (not shown) is coupled is provided in a groove shape on one of the surfaces of the filter housing 99 facing the second resonator post 32 or the other surface of the filter housing 99 facing the ninth resonator post 39. In one embodiment of the present invention, an embodiment in which the tuning resonator post 32' is provided on one surface of the filter housing 99 facing the second resonator post 32 has been described, but the present invention is not necessarily limited to this, and a tuning resonator post may also be provided on the other surface of the filter housing 99 facing the ninth resonator post 39.

[0088] 4 is a graph showing a plot (PLOT) of the characteristics of a waveguide filter according to the present invention, where the horizontal axis is frequency and the vertical axis is the cutoff performance (dB) of the filter.

[0089] As shown in FIGS. 1A to 3B, a waveguide filter 100 according to an embodiment of the present invention is provided such that one side of a filter housing 99 and the other side of the filter housing 99 are interconnected by resonator tunnels 80 formed in mirror symmetry with each other, so that, as shown in FIG. 4, two notches are formed on each side of the passband due to cross coupling of the signal characteristics.

[0090] As described above, the realized notch can be freely configured below or above the passband of the filter by changing the depth or shape of the second resonator post 32 or the ninth resonator post 39 associated with the formation of the notch and the shape and position of the resonator tunnel 80.

[0091] FIG. 5 is a schematic diagram illustrating the change in frequency characteristics according to the depth, width, and separation distance of the resonator tunnel from the partition slot in the configuration of a waveguide filter according to one embodiment of the present invention, and FIG. 6 is a graph showing a plot (PLOT) of the frequency characteristics according to the change in the depth of the resonator tunnel in the elements of FIG. 5.

[0092] The waveguide filter 200 shown in FIG. 5 is manufactured with a relatively simplified structure since it is intended to illustrate the results according to the shape of the resonator tunnel 280, unlike the waveguide filter 100 according to one embodiment of the present invention shown in FIGS. 1A to 3B.

[0093] For example, in the case of waveguide filter 100 according to one embodiment of the present invention, partition walls 51-60 and partition slots 71, 72 are all provided to separate the resonant blocks, whereas waveguide filter 200 shown in FIG. 5 does not have partition walls, and only partition slots 270a and 270b are provided to separate the resonant blocks.

[0094] Moreover, the waveguide filter 200 shown in FIG. 5 was manufactured so as to include six resonator blocks, each of which was provided with a resonator post 231 to 236.

[0095] In addition, a first resonator post 231, a second resonator post 232, a third resonator post 233, a fourth resonator post 234, a fifth resonator post 235 and a sixth resonator post 236 are provided in sequence along the signal line of the input post 221 and the output post 222, and the second resonator post 232 is provided on another side of the filter housing 99 different from the one side of the filter housing 99 which is the mounting surface of the other resonator posts 231, 233 to 236, so as to be inverted, and a tuning adjustment post 232' is provided on one side of the filter housing 99 which is the opposite side to the second resonator post 232.

[0096] In addition, the waveguide filter 200 shown in FIG. 5 has a second resonator post 232 and a fifth resonator post 235 that are interconnected by a resonator tunnel 280, and is provided with a resonator horizontal tunnel 281, a resonator vertical tunnel 282, and a resonator extension tunnel 283, like the waveguide filter 100 according to one embodiment of the present invention shown in FIGS. 1A to 3B.

[0097] Here, as shown in FIG. 5, the width of the resonator horizontal tunnel 281 or the resonator extension tunnel 283 is defined as "I2", the depth including the resonator horizontal tunnel 281 and the resonator extension tunnel 283 is defined as "H2", and the separation distance between the partition slots 270a and 270b sandwiching the resonator vertical tunnel 282 is defined as "J2".

[0098] FIG. 6 is a frequency characteristic plot (PLOT) showing the coupling effect between the second resonator post 232 and the fifth resonator post 235 when “H2”, one of the dimensions defined above, is increased by 1 mm (see FIG. 6(a)), 1.5 mm (see FIG. 6(b)), and 2 mm (see FIG. 6(c)).

[0099] As shown in FIG. 6, it can be seen that as the depth of the resonator horizontal tunnel 281 becomes larger (i.e., as it increases in the order of 1 mm-1.5 mm-2 mm), the amount of coupling increases (i.e., the length of F1-F2-F3 in FIG. 6 increases).

[0100] On the other hand, although not shown in the figure, when the width "I2" of the resonator horizontal tunnel 281 or the resonator extension tunnel 283 and the separation distance "J2" between the partition slots 270a and 270b sandwiching the resonator vertical tunnel 282 were changed, there was almost no change in the amount of coupling.

[0101] Therefore, it can be seen that the change in the amount of cross-coupling using the resonator tunnel 280 between the second resonator post 232 and the fifth resonator post 235 essentially depends on the magnitude of H2, which is the depth of the resonator horizontal tunnel 281.

[0102] 7A to 7C are schematic diagrams showing various application examples of a resonator tunnel in the configuration of a waveguide filter according to an embodiment of the present invention.

[0103] As shown in Figures 1A to 3B, in a waveguide filter 100 according to one embodiment of the present invention, among the configuration of resonator tunnels 80, resonator horizontal tunnel 81 is formed horizontally in the width direction of a filter housing 99, resonator extension tunnel 83 is formed to open and extend from one side of resonator horizontal tunnel 81 toward one surface of the filter housing 99, or is formed to open from the other side of resonator horizontal tunnel 81 toward the other surface of the filter housing 99, and resonator vertical tunnel 82 is formed to penetrate one and the other surfaces of the filter housing 99 and to pass through resonator horizontal tunnel 81.

[0104] However, as described above, the shape of the resonator tunnel 80 is not limited to the shape of the embodiment 100 of the present invention described above, but may be formed as various application examples as shown in FIGS. 7A to 7C.

[0105] 7A, the waveguide filter 210 according to the first application example does not form a structure corresponding to a resonator extension tunnel among the resonator tunnels 280, and among the resonator tunnels 280, the resonator horizontal tunnel 281 extends inclined rather than horizontally in the width direction of the filter housing 99 to interconnect the second resonator post 232 and the fifth resonator post 235 that are provided in an inverted manner. Here, among the resonator tunnels 280, the resonator vertical tunnel 282 may have the same structure as the shape of the above-mentioned embodiment 100.

[0106] 7B, the waveguide filter 220 according to the second application example includes a resonator extension tunnel 283 in the configuration of the resonator tunnel 280, similar to the waveguide filter 100 according to the above-mentioned embodiment, and the resonator horizontal tunnel 281 in the configuration of the resonator tunnel 280 can connect the second resonator post 232 and the fifth resonator post 235, which extend inclined rather than horizontally in the width direction of the filter housing 99 and are provided in an inverted manner, like the waveguide filter 210 of the first application example. Similarly, the resonator vertical tunnel 282 in the configuration of the resonator tunnel 280 can have the same structure as the shape of the above-mentioned embodiment 100 and the first application example 210.

[0107] As shown in FIG. 7C , the waveguide filter 230 according to the third application example does not form a configuration of the resonator tunnel 280 corresponding to the resonator extension tunnel and the resonator vertical tunnel, but simply has a resonator horizontal tunnel 281 among the configuration of the resonator tunnel 280, and can interconnect the second resonator post 232 and the fifth resonator post 235 that extend in an inverted manner to each other and inclined rather than horizontally in the width direction of the filter housing 99, as in the first application example 210 and the second application example 220.

[0108] FIG. 8 is a schematic diagram showing a resonator tunnel configured to realize side-by-side coupling as another embodiment of the present invention, and FIG. 9 is a graph showing a plot (PLOT) of the frequency characteristics of a waveguide filter according to the other embodiment of FIG.

[0109] A waveguide filter according to one embodiment of the present invention has been described in which, as shown in Figures 1A to 3B, two resonator posts (the second resonator post 32 and the ninth resonator post 39) are selected from among a plurality of resonator posts 31 to 40 and cross-coupled.

[0110] However, it is not necessary to cross-couple the two resonator posts formed in an inverted manner, and they may be adjacently coupled as shown in FIG.

[0111] That is, as shown in FIG. 8, a waveguide filter 300 according to another embodiment of the present invention is arranged on a signal line formed between an input post 221 and an output post 222, and is configured to interconnect a third resonator post 333 and a fourth resonator post 334 which are adjacent to each other but arranged in an inverted manner, using a resonator tunnel 380, so that the adjacent coupling of the adjacent resonator posts 333 and 334 can realize the notch desired by the designer.

[0112] More specifically, as shown in FIG. 8, a waveguide filter 300 according to another embodiment of the present invention has six resonator blocks each having a first resonator post 331, a second resonator post 332, a third resonator post 333, a fourth resonator post 334, a fifth resonator post 335 and a sixth resonator post 336, and an input post 321 is provided facing the other side of the filter housing 99 opposite to the formation direction of the first resonator post 331, and an output post 322 is provided facing the other side of the filter housing 99 opposite to the formation direction of the sixth resonator post 336.

[0113] Here, among the resonator posts arranged adjacent to each other on the signal line from the input post 321 to the output post 322, the third resonator post 333 is arranged on the other side of the filter housing 99 so as to be inverted from the other resonator posts 331, 332, 334, 335, and 336, and the adjacent fourth resonator post 334 is interconnected using a resonator tunnel 380, thereby enabling adjacent coupling to be realized.

[0114] The waveguide filter 300 according to another embodiment of the present invention having such a configuration has a different result in that, as shown in FIG. 9, only one notch is realized on each side of the passband, whereas in the case of the waveguide filter 100 according to the embodiment of the present invention realized by cross-coupling, two notches are realized on each side of the passband.

[0115] An embodiment of the waveguide filter 100 according to the present invention has been described above in detail with reference to the accompanying drawings. However, the embodiment of the present invention is not necessarily limited to the above-mentioned embodiment, and it is obvious that various modifications and equivalent implementations are possible by those skilled in the art to which the present invention pertains. Therefore, the true scope of the present invention is defined by the claims that follow. [Industrial Applicability]

[0116] The present invention achieves coupling through a resonator tunnel connecting the resonator posts. This provides a waveguide filter with enhanced characteristics in a particular passband. [Explanation of symbols]

[0117] 1~10: 1st resonator ~ 10th resonator 11-20: 1st resonance block to 10th resonance block 21: Input post 22: Output post 31-40: 1st resonator post to 10th resonator post 51~60: Bulkhead 71, 72: Compartment slots 80: Resonator tunnel 81: Resonator horizontal tunnel 82: Resonator vertical tunnel 99: Filter housing 100: Waveguide filter

Claims

1. A filter housing having one surface and another surface that define a thickness, the filter housing including a plurality of partitioned resonator blocks; a plurality of resonators each formed in the resonator block, the resonator posts each having an opening on one surface or the other surface of the filter housing and extending in a thickness direction of the filter housing; a resonator tunnel provided in the filter housing to interconnect two resonator posts among the plurality of resonator posts for coupling; the resonator tunnel includes a resonator horizontal tunnel extending between the one side and the other side of the filter housing and interconnecting at least two resonator posts of the plurality of resonator posts; The amount of coupling between the two resonator posts varies depending on the depth of the resonator horizontal tunnel, A waveguide filter, wherein the depth of the resonator horizontal tunnel is the distance from one or the other surface of the filter housing to the bottom surface of the resonator horizontal tunnel.

2. 2. The waveguide filter of claim 1, wherein the depth of the resonator horizontal tunnel is the thickness of the filter housing minus the thickness from the other surface of the filter housing to the bottom surface of the resonator horizontal tunnel.

3. 2. The waveguide filter of claim 1, wherein the depth of the resonator horizontal tunnel is equal to or less than the depth of the resonator post.

4. 2. The waveguide filter according to claim 1, wherein one of the two resonator posts connected by the resonator tunnel has an opening surface on one face of the filter housing, and the other resonator post has an opening surface on the other face of the filter housing, and is arranged in an inverted manner to enable cross-coupling.

5. The resonator tunnel is 2. The waveguide filter of claim 1, further comprising a resonator vertical tunnel extending through one side and the other side of the filter housing and connected to the resonator horizontal tunnel.

6. The resonator tunnel is 2. The waveguide filter according to claim 1, further comprising a resonator extension tunnel formed extending from said resonator horizontal tunnel and opening into one or the other surface of said filter housing.

7. 2. The waveguide filter according to claim 1, further comprising a tuning resonator post for tuning adjustment on one or the other surface of the filter housing facing one of the two resonator posts.

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