Wireless frequency filter with a cavity structure

Abstract

The present invention provides a wireless frequency filter having a cavity structure, comprising: a housing, which is hollow inside to form a cavity and has an open surface on one side; a resonance element located at the hollow position of the housing; a lid for sealing the open surface of the housing and having a groove with a nut structure at a position corresponding to the resonance element, the groove being recessed with a predetermined diameter and depth to form a film shape with a thinner bottom than other parts; a tuning screw screwed to the groove of the lid, and when the tuning screw is screwed to the groove, the bottom surface of the groove is pushed toward the resonance element side by the tuning screw and deformed.

Description

[0001] This application is a divisional application of the patent application with the application date of October 17, 2017, the application number of 2017800636911, and the invention title of "Wireless Frequency Filter with Cavity Structure". Technical Field

[0002] The present invention relates to a wireless signal processing device used in a wireless communication system, and in particular, to a cavity filter, a wireless frequency filter with a cavity structure (hereinafter may be simply referred to as "filter"). Background Art

[0003] A wireless frequency filter with a cavity structure usually forms a housing space such as a cube through a metal housing, that is, forms a plurality of cavities, and each cavity internally has a resonance element composed of a dielectric resonance element (DR) or a metal resonance rod to generate ultra-high frequency resonance. Moreover, in the wireless frequency filter with this cavity structure, usually, the upper part of the cavity structure has a lid for shielding the open surface of the cavity, and a plurality of tuning screws and nuts for fixing the tuning screws may be installed on the lid to serve as a tuning structure for tuning the filtering characteristics of the wireless frequency filter. As an example of a wireless frequency filter with a cavity structure, the content described in Korean Patent Publication No. 10-2004-100084 (invention title: "Wireless Frequency Filter", publication date: December 02, 2004, inventors: Park Jong-gyu et al., 2 people), which is the prior application of this application, can be cited.

[0004] A wireless frequency filter with such a cavity structure is used to process radio transceiver signals in a wireless communication system. In particular, it is typically applied to a base station or a relay station in a mobile communication system.

[0005] In addition, Korean Patent Publication No. 10-2014-0026235 (invention title: "Wireless Frequency Filter with Cavity Structure", publication date: March 5, 2014, inventors: Park Nam-shin and 2 others), which is a prior application of the present application, proposed a simple and simplified filter structure that can achieve frequency tuning without using the fixing structure of tuning screws and fixing nuts. The above-mentioned Korean Patent Publication No. 10-2014-0026235 proposed a technique of forming one or more recessed portions at positions corresponding to resonance elements on a lid made of a plate-shaped base material of aluminum or magnesium (including alloys) by stamping or die-casting. Moreover, on such recessed portions, a plurality of dot peen structures are formed based on the stamping or pressing of a stamping pin of an external engraving device. Such recessed portions and dot peen structures are used to replace the fixing structure of tuning screws and fixing nuts commonly used in frequency tuning, and appropriate tuning operations can be achieved by reducing the distance between the recessed portions (and dot peen structures) and the resonance elements.

[0006] Since the technique described in the above-mentioned Korean Patent Publication No. 10-2014-0026235 does not adopt the combined structure of general tuning screws and fixing nuts, it can be applied to small and lightweight filter structures. Moreover, this structure can eliminate the PIMD (Passive Intermodulation Distortion) components caused by the discontinuous and uneven contact surfaces between the existing tuning screws and the screw holes of the housing or the bonding between dissimilar metals.

[0007] However, the technique described in the above-mentioned Korean Patent Publication No. 10-2014-0026235 has the problem that an additional external engraving device needs to be purchased for tuning operations. Moreover, in the method of forming dot peen structures on the recessed portions of the filter using an external engraving device, since the formed dot peen structures are removed, it is actually impossible to restore the recessed portions to their original form. Thus, the tuning operation is carried out in an irreversible manner, and therefore there are difficulties during the tuning operation. Summary of the Invention

[0008] (1) Technical Problems to be Solved

[0009] Therefore, at least some embodiments of the present invention aim to provide a wireless frequency filter with a cavity structure that can be tuned without using the combined structure of existing tuning screws and fixing nuts, and can be manufactured with a simpler manufacturing process and lower manufacturing costs.

[0010] In at least some other embodiments of the present invention, a wireless frequency filter having a cavity structure is provided, which can achieve the above object and can also perform a tuning operation reversibly, making the tuning operation easier.

[0011] (II) Technical Solution

[0012] To achieve the above object, according to an embodiment of the present invention, a wireless frequency filter having a cavity structure is characterized by comprising: a housing, which is hollow inside to form a cavity and has an open surface on one side; a resonance element, which is located at the hollow position of the housing; a lid, which is used to seal the open surface of the housing and has a groove with a nut structure at a position corresponding to the resonance element, the groove being recessed with a predetermined diameter and depth to form a thin film shape with a thinner bottom than other parts; a tuning screw, which is screw-coupled to the groove of the lid, and when the tuning screw is screw-coupled to the groove, the bottom surface of the groove is pushed towards the resonance element side by the tuning screw and deformed.

[0013] According to another embodiment of the present invention, a wireless frequency filter having a cavity structure is characterized by comprising: a housing, which is hollow inside to form a cavity and has an open surface on one side; a resonance element, which is located at the hollow position of the housing; a lid, which is used to seal the open surface of the housing and has a through-hole with a nut structure at a position corresponding to the resonance element, the through-hole having a predetermined diameter; a metal plate, which is disposed between the lid and the housing and has a size corresponding to that of the lid; a tuning screw, which is screw-coupled to the through-hole of the lid, and when the tuning screw is screw-coupled to the through-hole, the part corresponding to the metal plate is pushed towards the resonance element side by the tuning screw and deformed.

[0014] (III) Advantageous Effects

[0015] As described above, the wireless frequency filter having a cavity structure according to some embodiments of the present invention provides a structure that can be tuned even without using the existing combination structure of a tuning screw and a fixing nut, so that it can be manufactured with a simpler manufacturing process and lower manufacturing cost. Moreover, in at least some other embodiments of the present invention, the tuning operation can also be performed reversibly, making the tuning operation easier. Description of the Drawings

[0016] Figure 1 is a partially separated cross-sectional view of a wireless frequency filter having a cavity structure according to the first embodiment of the present invention.

[0017] Figure 2 is Figure 1 a combined view of the separated parts.

[0018] Figure 3 is Figure 1 a perspective view of the frequency tuning screw.

[0019] Figure 4 is a partially separated sectional view of a wireless frequency filter having a cavity structure according to a second embodiment of the present invention.

[0020] Figure 5 is Figure 4 a combined view of the separated part of

[0021] Figure 6 is Figure 4 a perspective view of Detailed Description of the Preferred Embodiment

[0022] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following drawings, the same reference numerals are used as much as possible for the same components, and for ease of explanation, their dimensions or shapes are somewhat simplified or partially exaggerated.

[0023] Figure 1 is a partially separated sectional view of a wireless frequency filter having a cavity structure according to a first embodiment of the present invention, showing a state in which the frequency tuning screw 31 is disassembled. Figure 2 is Figure 1 a combined view of the separated part (i.e., the tuning screw) of Figure 3 is Figure 1 a perspective view of the frequency tuning screw of Figures 1 to 3 , the wireless frequency filter having a cavity structure according to the first embodiment of the present invention is similar to the prior art and has a casing, which is hollow inside and has at least one cavity isolated from the outside. The casing forms the cavity and includes a housing 21 open on one side (e.g., the upper side) and a lid 11 for sealing the open surface of the housing 21. The central part of the cavity formed inside the housing 21 is formed in a state where the resonance element 41 is fixedly provided on the bottom surface inside the housing 21.

[0024] In Figures 1 to 3 the example of Figures 1 to 3 for ease of explanation, for example, the housing 21 is shown to be formed with a single cavity structure. However, in addition to this structure, the housing 21 may also have a structure in which a plurality of cavities are connected in multiple stages, and each cavity may have a resonance element at its central part. Moreover,

[0025] In the above structure, the structure of the outer shell 21, the cavity structure formed based on the outer shell 21, and the resonance element 41 can be similar to those in the prior art, and both the outer shell 21 and the resonance element 41 can be made of materials in the aluminum series (alloys). In addition, the lid 11 in an embodiment of the present invention is also similar to the prior art and can use the same material as the outer shell 21, that is, a material in the aluminum series.

[0026] However, a recessed groove 112 is formed in the lid 11, and the groove 112 is recessed from a position corresponding to the resonance element 41 in the cavity of the outer shell 21 with a predetermined diameter and depth. The thickness of the bottom a of the groove 112 is different from the remaining other parts of the lid 11 and is formed in a thinner film shape. For example, when the thickness of other parts in the lid 11 is about 2.0 - 3.0 mm, the thickness of the bottom of the groove 112 can be about 0.1 - 0.3 mm. Moreover, the diameter of the groove 112 can be about 4.0 - 4.5 mm.

[0027] A screw coupling structure can be formed on the side of the groove 112 to couple the frequency tuning screw 31 for tuning the frequency. That is, the groove 112 has a screw groove structure of a nut, so that the frequency tuning screw 31 can be integrally coupled in a screw coupling manner.

[0028] The side of the frequency tuning screw 31 has a bolt structure that is screw-coupled with the groove 112, and a suitable coupling groove 312 is formed at the upper end (i.e., the head) to be connected to an external screwdriver device (screwdriver, wrench, etc.) for screw tightening operation. In Figures 1 to 3 the example, the coupling groove 312 is illustrated as a slotted type. At the lower end of the frequency tuning screw 31, that is, the part in contact with the bottom a of the groove 112, a protruding part 313 that protrudes downward is formed. The protruding part 313 can be formed in a stepped structure so that the diameter of the lower end part of the frequency tuning screw 31 is smaller. For example, when the diameter of the frequency tuning screw 31 is about 4.0 - 4.5 mm, the diameter of the protruding part 313 can be about 2.5 - 3.5 mm. Moreover, the height of the protruding part 313 can be about 0.5 - 1.0 mm.

[0029] In the filter structure as described above, during the frequency tuning operation, the frequency tuning screw 31 is coupled to the groove 112 of the lid 11 and tightened. As the frequency tuning screw 31 is tightened, the protruding part 313 of the frequency tuning screw 31 will squeeze the bottom surface part a of the groove 112. Thus, as Figure 2 further illustrated in detail, the bottom a of the groove 112 of the lid 11 is pushed toward the resonance element 41 side inside the cavity. Therefore, the distance between the lower side of the lid 11, that is, the bottom a of the groove 112 and the resonance element 41 (i.e., Figure 1 the d1 of Figure 2d2) is adjusted to regulate the capacitance component between the lid 11 and the resonance element 41, thereby regulating the characteristics of the filtering frequency.

[0030] At this time, when the bottom a of the groove 112 of the lid 11 has a certain elasticity, the frequency characteristics are adjusted by repeatedly tightening or loosening the frequency tuning screw 31.

[0031] In addition, based on the thickness of the lid 11 and the tightened state during the tuning operation, etc., the overall height of the frequency tuning screw 31 including the protruding portion 313 is set such that the upper end of the frequency tuning screw 31 does not protrude from the upper surface of the lid 11 at least after the frequency tuning operation is completed. In this case, the overall shape and size of the filter can be optimized.

[0032] In addition, after the frequency tuning operation is completed, in order to maintain the fixed state of the frequency tuning screw 31, an adhesive resin such as epoxy (not shown) can be applied to the joint portion between the frequency tuning screw 31 and the groove 112 of the lid 11.

[0033] Figure 4 is a partially separated cross-sectional view of a wireless frequency filter having a cavity structure according to the second embodiment of the present invention. Figure 5 is Figure 4 a combined view of the separated parts. Figure 6 is Figure 4 a perspective view. Referring to Figures 4 to 6 , the wireless frequency filter according to the second embodiment of the present invention has the same structure as that of the first embodiment shown in Figures 1 to 3 , and has an open housing 22 and a casing on the upper side. The casing includes a lid 12 for sealing the upper side of the housing 22. A resonance element 42 (42-1, 42-2) is formed at the central portion of the cavity formed in the housing 22, and is fixedly provided on the bottom surface inside the housing 22.

[0034] In Figures 4 to 6 's example, for example, it is illustrated that the housing 22 has two cavity structures. A coupling window 224 is formed between the two cavities, which has a connection path structure for coupling the cavities to each other. The coupling window 224 can be formed in a form of cutting off a certain portion according to a predetermined size at a portion equivalent to a partition between the cavity structures. Moreover, although not shown in Figures 4 to 6 , the input terminal of this wireless frequency filter is configured to be connected to one of the two cavities of the housing 22, and the output terminal is configured to be connected to the other cavity.

[0035] In the filter according to the second embodiment of the present invention having the above-described structure, holes 122 (122-1, 122-2) penetrating the lid 12 are formed in the lid 12, and the holes 122 are formed at positions corresponding to the respective resonance elements 42-1, 42-2 in the cavity of the housing 22 and have a predetermined diameter. A screw coupling structure is formed on the side surface of the hole 122 to couple frequency tuning screws 32 (32-1, 32-2) for tuning the frequency. Thus, it can be seen that the hole 122 has a nut structure for integrally coupling the frequency tuning screws 32 in a screw-coupling manner.

[0036] Each of the frequency tuning screws 32 has a bolt structure for screw-coupling with the hole 122 on the side surface. At this time, in Figures 4 to 6 the illustrated example, the frequency tuning screw 32 is illustrated as having a uniform diameter from the upper end to the lower end as a whole.

[0037] In addition, in Figures 4 to 6 the structure of the illustrated second embodiment, between the lid 12 and the housing 22, for example, a thin metal plate 62 is arranged for tuning the frequency, and its size is substantially the same as the size of the lid. The metal plate 62 can be made of a material such as aluminum, copper, or an iron series, and its thickness can be about 0.05 to 0.2 mm.

[0038] The metal plate 62 can be fixedly attached to the lid 12 by welding. For example, solder or solder paste ( Figure 4 c) is provided at a suitable position preset under the lid 12, and a reflow soldering process or the like is performed, so that the metal plate 62 and the lid 12 can be soldered. Similarly, the portion of the lower surface of the metal plate 62 in contact with the housing 22 can also be fixedly attached by welding.

[0039] An auxiliary groove b can be formed at the lower end of the through-hole 122 of the lid 12, which is in a form where the edge portion is further cut off so that its diameter is larger than the diameter of other portions of the through-hole 122. Thus, it can be seen that the through-hole 122 has a stepped structure, and the diameter of the whole lower end portion is larger.

[0040] The auxiliary groove b is a structure for preventing the coating of solder paste during the welding operation with the metal plate 62. For example, during the welding operation, the method of printing solder paste on the lower surface of the lid 12 can be used. At this time, the solder paste will not be printed at the portion where the auxiliary groove b is formed. As described above, based on the auxiliary groove b of the through-hole 122, the remaining portion of the metal plate 12 that is not welded to the lid 12 includes the portion in contact with the frequency tuning screw 32 and has a certain space. Thus, it can be seen that the portion of the metal plate 12 corresponding to the frequency tuning screw 32 can be extruded to a certain extent by the frequency tuning screw 32.

[0041] In the filter structure described above, when tuning the frequency, the frequency tuning screw 32 is combined with and fastened to the through-hole 122 of the lid 12. As the frequency tuning screw 32 is tightened, the lower end of the frequency tuning screw 32 passes through the hole 122 and contacts and presses the corresponding part on the upper surface of the metal plate 62. Thus, as Figure 5 As shown in further detail, the part of the metal plate 62 corresponding to the frequency tuning screw 32 is pushed toward the resonance element 42 side inside the cavity. Therefore, the distance between the lower surface of the metal plate 62 and the resonance element 42 is adjusted, thereby adjusting the characteristics of the filtering frequency.

[0042] In addition, as described above, when the metal plate 62 has a certain elasticity, the frequency characteristics are adjusted by repeatedly tightening or loosening the frequency tuning screw 32.

[0043] Furthermore, based on the thickness of the lid 12 and the tightened state during the tuning operation, etc., the overall height of the frequency tuning screw 32 is set such that the upper end of the frequency tuning screw 32 does not protrude from the upper surface of the lid 12 at least after the frequency tuning operation.

[0044] In addition, in Figures 4 to 6 the embodiment, in addition to the frequency tuning screw 32, the state in which a coupling tuning screw 52 for cavity - to - cavity coupling is provided on the lid 12 is further illustrated. That is, the coupling tuning screw 52 is screwed to the screw hole 124 and can protrude toward the coupling window 224 through the screw hole 124, and the screw hole 124 is formed on the lid 12 and corresponds to the coupling window 224.

[0045] In the structure described above, in order to make the coupling tuning screw 52 protrude toward the coupling window 224, a through - hole 622 is formed in the corresponding part of the metal plate 62.

[0046] The wireless frequency filter having a cavity structure according to an embodiment of the present invention may have the structure described above. In addition, various embodiments or variations may also be included in the present invention. For example, in the above description, Figures 4 to 6 in the second embodiment illustrated, the overall diameter of the frequency tuning screw 32 is uniform, but in addition to this, as illustrated in Figures 1 to 3 the frequency tuning screw 32 may also have a structure with a protrusion formed at the lower end. And in this case, depending on the situation, Figures 4 to 6 the through - hole 122 formed on the lid 120 illustrated may also have a structure without an auxiliary groove b at the lower end.

[0047] In addition, the resonance element can also be fabricated and attached to the inner bottom surface of the housing through other means. Moreover, in the present invention, the housing and the resonance element can be made of the same material, and the housing and the resonance element can also be integrally formed by die-casting. Alternatively, in addition to this, as described in the technology recorded in the above-mentioned Invention Patent Gazette No. 10-2014-0026235, the housing and the internal resonance element can also have a structure integrally formed by stamping as a whole.

[0048] In addition, it should be noted that various design deformations can be made for the specific structures or dimensions, etc. of the detailed constituent elements such as the frequency tuning screws, grooves, through holes, etc., including the number and shape of the cavities provided on the cartridge.

[0049] As described above, the present invention can have various deformations and changes. Therefore, the scope of the present invention should be determined by the claims and their equivalents, rather than by the described embodiments.

[0050] Cross-reference to related applications

[0051] According to Article 119(a) of the United States Patent Law (35 U.S.C. 119(a)), this patent application claims the priority of the Invention Patent Application No. 10-2016-0139478 filed with the Korean Patent Office on October 25, 2016, and all its contents are included in this patent application as references. At the same time, for the above reasons, this patent application can also claim priority in other countries outside the United States, so all its contents are also included in this patent application as references.

Claims

1. A wireless frequency filter having a cavity structure, the wireless frequency filter comprising: A housing having a hollow space therein and an open face for providing at least one cavity; At least one resonance element located in the hollow space of the housing; A lid for sealing the open face of the housing and having at least one groove with a nut structure at a position corresponding to the resonance element, the groove being recessed with a predetermined diameter and depth, and the bottom of the lid being thinner than other parts; At least one tuning screw screwed onto the groove of the lid, Wherein when the tuning screw is screwed onto the groove, the bottom surface of the groove is pushed towards the resonance element side by the tuning screw and deformed, and Wherein an auxiliary groove is formed at the lower end of the groove, the auxiliary groove being in a form with the edge part cut off and the diameter of the auxiliary groove being larger than the diameter of other parts of the groove.

2. A wireless frequency filter having a cavity structure, the wireless frequency filter comprising: A housing having a hollow space therein and an open face for providing at least one cavity; At least one resonance element located in the hollow space of the housing; A lid for sealing the open face of the housing and having at least one through-hole with a nut structure at a position corresponding to the resonance element, the through-hole having a predetermined diameter, and the bottom of the lid being thinner than other parts; A metal plate disposed between the lid and the housing and having a size corresponding to the size of the lid; At least one tuning screw screwed onto the through-hole of the lid, Wherein when the tuning screw is screwed onto the through-hole, the part corresponding to the metal plate is pushed towards the resonance element side by the tuning screw and deformed, and Wherein an auxiliary groove is formed at the lower end of the through-hole of the lid, the auxiliary groove being in a form with the edge part cut off and the diameter of the auxiliary groove being larger than the diameter of other parts of the through-hole.

3. The wireless frequency filter according to claim 1 or 2, wherein, A protruding portion protruding downward is formed at the lower end of the tuning screw.

4. The wireless frequency filter according to claim 2, wherein, The lower end of the through-hole of the lid is formed in a stepped structure such that the diameter of the lower end is larger than the diameter of other parts.

5. The wireless frequency filter according to claim 2 or 4, wherein, The metal plate is fixedly attached to the lid by a welding method.

6. The wireless frequency filter according to claim 2 or 4, wherein, The housing has at least two cavities, A coupling window as a connection path structure is formed between the at least two cavities, A screw hole is formed on the lid corresponding to the coupling window, A through-hole for adjusting coupling is formed on the metal plate corresponding to the screw hole formed on the lid, The coupling tuning screw is coupled to the screw hole in a screw-coupling manner and protrudes toward the coupling window side through the screw hole and the through hole for adjusting the coupling.

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