Communications equipment filters

Abstract

A filter for communication equipment is provided that can simplify the complexity of the filter and achieve a variety of filter performances. [Solution] The filter for a communication device includes notch forming portions that are arranged relatively closer than the separation distance between the portions where magnetic field coupling or electric field coupling is dominant of each of the adjacent resonant elements among at least three or more adjacent resonant elements selected sequentially along the longitudinal direction of the cavity for multipath coupling, and form predetermined notches at the left and right ends of the passband to limit the range of filtering frequencies.

Description

[Technical Field]

[0001] The present invention relates to a filter for communication devices, and more particularly to a filter for communication devices in which a cavity is formed by a folding method in a front-end process, and multiple resonators are arranged separately inside the cavity, and notch forming portions are provided adjacent to the resonators to form L-notch portions by inductive coupling and C-notch portions by capacitive coupling at both ends of a bandpass. [Background technology]

[0002] Radio frequency devices (including all "communications devices") such as radio frequency filters are typically constructed with a structure in which multiple resonators are connected. Such resonators are circuit elements that resonate at a specific frequency by combining an inductor (L) and a capacitor (C) in an equivalent electronic circuit. Each resonator has a structure in which a dielectric resonance element (DR) or a metal resonance element is provided inside a cavity such as a metallic cylinder or rectangular parallelepiped surrounded by a conductor. As a result, each resonator has a structure that enables high-frequency resonance by allowing only an electromagnetic field of a natural frequency according to the processing frequency band to exist within the cavity. Typically, multiple resonant ends are formed using multiple cavities, and a multi-stage structure is formed in which the multiple resonant ends are connected in sequence.

[0003] An example of a radio frequency filter having a multiple cavity structure is disclosed in Korean Patent Publication No. 10-2004-0100084 (title: "Radio Frequency Filter", publication date: December 2, 2004), which was filed earlier by the applicant of the present application.

[0004] However, in conventional radio frequency filters, each resonator extends in the thickness direction within the cavity, and the distance between the resonators is tuned by deforming a part of the filter tuning cover covering the cavity by stamping to obtain the desired bandpass characteristics. This presents a significant limitation in reducing the size of the completed filter in the thickness direction.

[0005] Furthermore, conventional radio frequency filters require the installation of additional conductive material structures to realize inductive or capacitive coupling in order to enhance skirt characteristics between adjacent resonators or between distant resonators in multiple cavities, which has been pointed out as a problem in that the weight of the completed filter increases significantly.

[0006] Meanwhile, in recent years, in antenna devices to which Massive MIMO (Multiple Input-Multiple Output) technology is applied, research is being conducted to minimize the thickness of internal components such as filters in order to slim down the entire product, and the most commonly used type of filter for this purpose is a dielectric ceramic filter.

[0007] However, due to the characteristics of the material, dielectric ceramic filters are bonded directly to one side of the main board (or PA board) stacked inside the antenna housing, which means that they are limited to being used on both sides of the PCB (printed circuit board). Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned technical problems, and has as its object to provide a filter for communications equipment in which a cavity is formed by a folding method and a notch-forming section with a simple and easy configuration is constructed within a relatively small interior that is relatively small in size in the thickness direction, thereby ensuring a wide range of frequency characteristics and facilitating the design of notches on both sides of the passband.

[0009] The objects of the present invention are not limited to those mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0010] The filter for a communication device according to one embodiment of the present invention configured as described above includes: a base plate forming a hexahedral cavity whose longitudinal direction is the up-down direction and whose thickness in the front-to-back direction is at least smaller than its width in the left-to-right direction, when the radiation direction of the antenna element is defined as the front-to-back direction; a plurality of resonators forming identical layers in the front-to-back direction (thickness direction) of the cavity; an input port section for inputting a predetermined signal to one of the plurality of resonators at one end closest to one longitudinal end of the cavity; and an output port section for outputting a predetermined signal from one of the plurality of resonators at the other end closest to the other longitudinal end of the cavity, the input port section and the output port section being arranged within the cavity and sequentially selected along the longitudinal direction; and a notch forming section arranged to be relatively closer than the separation distance between portions of adjacent resonant elements including the plurality of resonators where magnetic field coupling or electric field coupling is dominant.

[0011] Here, the plurality of resonators excluding the input port portion and the output port portion of the resonant element may be formed so that the tip portion corresponding to the other end in the width direction in the left-right direction is divided into resonant ends which are portions where the electric field coupling is dominant (hereinafter referred to as "electric field portions") and which are larger in size in the longitudinal direction than other portions where the magnetic field coupling is relatively dominant (hereinafter referred to as "magnetic field portions").

[0012] The notch forming portion may include an L-notch portion formed adjacent to the magnetic field portion so that the entire portion only affects the magnetic field portion, and a C-notch portion formed adjacent to the L-notch portion so that a portion of the L-notch portion only affects the electric field portion.

[0013] In addition, the L-notch portion and the C-notch portion may function as a cross-coupling bar that couples across at least one or more of the plurality of resonators sequentially arranged in the longitudinal direction.

[0014] The L-notch portion and the C-notch portion may be arranged to form the same layer in the thickness direction of the cavity, and may be arranged to form a layer different from that of the plurality of resonators.

[0015] The L-notch portion may be configured to form a closed loop extending from one widthwise side of the cavity to the other widthwise side.

[0016] The C-notch portion may extend from one widthwise side of the cavity to the other widthwise side thereof and be disposed adjacent to any one of the resonator ends of the plurality of resonators.

[0017] In addition, the L-notch portion may be disposed relatively closer than the separation distance between the electric field portions of adjacent resonant elements among at least three or more adjacent resonant elements sequentially selected along the longitudinal direction for multipath coupling, thereby forming a predetermined notch at the right end of the passband to limit the range of filtering frequencies.

[0018] In addition, the C-notch portion may be arranged relatively closer than the separation distance between the magnetic field portions of adjacent resonant elements among at least three adjacent resonant elements sequentially selected along the longitudinal direction for multipath coupling, thereby forming a predetermined notch at the left end of the passband and limiting the filtering frequency range.

[0019] In addition, the L-notch portion and the C-notch portion may be defined as either the L-notch portion or the C-notch portion depending on the properties of the electric field portion and the magnetic field portion that are relatively strongly expressed due to adjacent coupling or the cross-coupling among the plurality of resonators.

[0020] Furthermore, when the L-notch portion and the C-notch portion are provided in other ranges in the longitudinal direction of the cavity, the resonators may be defined as either the L-notch portion or the C-notch portion depending on the properties of the electric field portion and the magnetic field portion.

[0021] Furthermore, when the L-notch portion and the C-notch portion are provided in a single configuration in the same range in the longitudinal direction of the cavity, they may be defined as a composite configuration that simultaneously has the functions of the L-notch portion and the C-notch portion depending on the properties due to adjacent coupling and the properties due to cross coupling among the multiple resonators.

[0022] Furthermore, when the input port portion and the output port portion are included as the coupled resonating elements, the C-notch portion may be formed to branch from the input port portion, cross the one-side resonator, and extend toward the resonating end of the adjacent resonator.

[0023] Furthermore, when the input port portion and the output port portion are included as the coupled resonator elements, the L-notch portion can be branched from the output port portion and connected to the adjacent resonator across the other side end resonator.

[0024] The cavity can be formed by folding the single base plate.

[0025] The notch forming portion can also be manufactured as a separate panel and coupled to the corresponding structure of the base plate or to the interior of the cavity.

[0026] The notch forming portion may be formed integrally with the base plate and in the form of a panel that is positioned inside the cavity when folded. [Effects of the Invention]

[0027] In a filter for a communications device according to one embodiment of the present invention, a cavity is formed by a folding method, and a notch-forming portion with a simple and easy configuration is constructed within an interior that is relatively small in size in the thickness direction, thereby ensuring a variety of frequency characteristics and providing the advantage of facilitating the design of notches on both sides of the passband. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a perspective view showing a filter for a communication device according to an embodiment of the present invention; [Figure 2] FIG. 2 is an internal perspective view of FIG. [Figure 3] FIG. 2 is a perspective view of the base plate of the configuration of FIG. 1 in an expanded state. [Figure 4] FIG. 4 is a plan view of FIG. 3. [Figure 5] 2 is an exploded perspective view showing an embodiment in which the input terminal pins and the output terminal pins are provided as separate parts in the configuration of FIG. 1. FIG. [Figure 6] (a, b) are perspective cutaway views along line AA. [Figure 7] 1 is a plan view illustrating the principle and structure of notch formation in a first embodiment of a filter for a communication device according to an embodiment of the present invention, which uses a notch forming portion. FIG. [Figure 8] FIG. 8 is an internal perspective view of FIG. [Figure 9] FIG. 8 is a circuit diagram of FIG. [Figure 10] 8 is a graph showing the frequency characteristics of FIG. 7. [Figure 11] FIG. 10 is a plan view illustrating the principle and structure of notch formation in a second embodiment of the filter for a communication device according to an embodiment of the present invention, which uses a notch forming portion. [Figure 12] FIG. 12 is an internal perspective view of FIG. [Figure 13] FIG. 12 is a circuit diagram of FIG. [Figure 14] 12 is a graph showing the frequency characteristics of FIG. 11. [Figure 15]FIG. 10 is a plan view illustrating the principle and structure of notch formation in a third embodiment of the filter for a communication device according to an embodiment of the present invention, which uses a notch forming portion. [Figure 16] FIG. 16 is an internal perspective view of FIG. [Figure 17] FIG. 16 is a circuit diagram of FIG. [Figure 18] 16 is a graph showing the frequency characteristics of FIG. 15. [Figure 19] FIG. 10 is a plan view illustrating the principle and structure of notch formation in a fourth embodiment of the filter for a communication device according to an embodiment of the present invention, which uses a notch forming portion. [Figure 20] FIG. 20 is an internal perspective view of FIG. [Figure 21] 20 is a graph showing the frequency characteristics of FIG. 19. DETAILED DESCRIPTION OF THE INVENTION

[0029] The advantages and features of the present invention, as well as methods for achieving them, will become more apparent 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 can be realized in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully convey the scope of the invention to those skilled in the art. The present invention is defined solely by the scope of the claims. The same reference numerals refer to the same elements throughout the specification.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0031] FIG. 1 is a perspective view showing a filter for a communication device according to a first embodiment of the present invention, FIG. 2 is an internal perspective view of FIG. 1, FIG. 3 is a perspective view of the base plate of the configuration of FIG. 1 in an expanded state, FIG. 4 is a plan view of FIG. 3, FIG. 5 is an exploded perspective view showing an embodiment of the configuration of FIG. 1 in which the input terminal pin and the output terminal pin are provided as separate parts, and FIG. 6 is a cutaway perspective view (a, b) along line AA.

[0032] A communication antenna includes a filter for filtering signals of a specific passband. Depending on the characteristics, a cavity filter, a waveguide filter, etc. can be used as the filter. In the embodiment of the present invention, a type of cavity filter, which is manufactured by folding a single base plate to form a cavity that serves as the main signal transmission path, rather than by the conventional molding method, will be described.

[0033] Generally, in the field of antenna technology, a filter is a communication component that filters out only signals of a specific frequency band from among signals to be input or output during a transmission / reception process, so that only the signal desired by the consumer (user) is obtained as a result.

[0034] To filter such signals, a cavity filter, as the name suggests, forms a cavity, which is a predetermined signal filtering section (signal transmission path), between an input port where the signal is input and an output port where the signal is output, and obtains a frequency signal value of a specific band in the section desired by the consumer through a frequency tuning process through the cavity.

[0035] However, until now, the only method that has been developed and disclosed in the industry for manufacturing antenna devices for manufacturing cavity filters is to manufacture the above-mentioned cavity by processing the inside of a filter body made of a ceramic material (dielectric material) or a more rigid material, and then to manufacture the essential components for frequency filtering, such as multiple resonators, and then fix them inside the cavity.

[0036] However, the filter for communication devices according to an embodiment of the present invention breaks away from the above-mentioned manufacturing method and discloses an innovative technical feature in which a single flat base plate not exceeding a predetermined thickness is processed into a sheet metal shape, and then a structure within a cavity can be constructed by a folding process without using a separate joining process.

[0037] However, before describing filters 100, 100A-D for communication devices according to embodiments of the present invention, the shape of cavity C and the position and shape of notch forming portion 140 disposed therein can be very important elements in understanding the present invention, and therefore, definitions of terms related to directionality can be set as follows.

[0038] In other words, the beam radiation direction of the antenna element (radiating element) (not shown) can generally be defined as the front-rear direction. More specifically, the antenna elements can be arranged in multiple rows in the up-down or left-right direction on the front surface of the antenna housing (not shown).

[0039] Such an antenna element can be stacked on the front surface of the filter 100, 100A to 100D for a communication device according to the embodiment of the present invention, which is disposed inside the antenna housing, with an antenna board assembly (not shown) interposed therebetween.

[0040] Here, the cavity C of the communication device filter 100, 100A-D according to the embodiment of the present invention may be formed as a hexahedron whose thickness in the front-to-rear direction is smaller than at least the width in the left-to-right direction and whose longitudinal direction is in the up-to-down direction.

[0041] Therefore, the front-to-back direction, which is the slimmest part of the hexahedron forming cavity C, may be defined as the "thickness direction," the left-to-right direction as the "width direction," and the up-to-down direction as the "longitudinal direction."

[0042] The filter 100 for a communication device according to one embodiment of the present invention is manufactured in an unfolded state and includes a base plate 105 made of a conductive material that is foldable so that a cavity C is formed therein when folded, and a plurality of resonators 170 protruding a predetermined length in the thickness direction or width direction are positioned within the cavity C.

[0043] It is preferable that the base plate 105 is made of a conductive material, but it can also be made of a non-conductive material that is easy to manufacture, and it should be noted in advance that a conductive material can be coated on both the inside and outside, including the cavity C, using a plating method so that it can function as a signal transmission path (or signal filtering section) for the cavity C.

[0044] However, since the base plate 105 must maintain its shape continuously after being deformed by the folding process as described below unless an external force is applied, it is preferable that the base plate 105 be made of a suitable deformable material.

[0045] Here, the cavity C is a dielectric-filled space to be filled with a dielectric having a predetermined dielectric constant, and refers to a space that is empty inside so that it can be filled with a dielectric. It should be made clear in advance that, since air is a type of dielectric having a dielectric constant of 1, when air under atmospheric pressure is used as the dielectric, a separate dielectric filling step is not required.

[0046] Meanwhile, in the filter 100 for a communication device according to the embodiment of the present invention, the base plate 105 serves to form a cavity C, which is a space filled with a dielectric.

[0047] Here, as shown in Figures 3 and 4, the base plate 105 may include a body bottom forming panel 110 that forms the bottom of the cavity C, one-side thickness forming panel 120 and other-side thickness forming panel 130 that are extended in plan so that the width increases at one and other widthwise ends of the body bottom forming panel 110, thereby increasing the thickness of the cavity C, a resonator panel 160 that is extended from the tip of one of the one-side thickness forming panel 120 and other-side thickness forming panel 130 and has a plurality of resonators 170 protruding into the cavity C corresponding to the upper part of the body bottom forming panel 110, and an upper body forming panel 150 that is extended from the other tip of the one-side thickness forming panel 120 and other-side thickness forming panel 130 and is configured to face the body bottom forming panel 110 and cover the upper part of the cavity C.

[0048] In addition, one side shielding panel 180A and the other side shielding panel 180B that shield the open one and other longitudinal ends of the cavity C can be integrally formed at one and other longitudinal ends of the body bottom forming panel 110 by extending them.

[0049] Here, the description is limited to the case where the one-side shielding panel 180A and the other-side shielding panel 180B are integrally formed with the body bottom forming panel 110, but it goes without saying that in some embodiments, they may be symmetrically formed integrally with adjacent panels (e.g., the body upper forming panel 150, etc.). Also, the one-side shielding panel 180A and the other-side shielding panel 180B may be formed integrally with adjacent panels so as to be separated into two members, and may be provided so as to completely shield each open cavity C portion by a folding operation.

[0050] Meanwhile, the body bottom forming panel 110 may be provided with an input port mounting portion 115A and an output port mounting portion 115B formed by penetrating vertically at one longitudinal end and the other longitudinal end, respectively, and an input terminal pin 175A' described later may be inserted through the input port mounting portion 115A, and an output terminal pin 175B' described later may be inserted through the output port mounting portion 115B.

[0051] In particular, although not shown, the input terminal pin 175A' and the output terminal pin 175B' inserted into the input port mounting portion 115A and the output port mounting portion 115B are surrounded by Teflon (registered trademark) having a stud or serration protrusion shape on the outer periphery, thereby minimizing insertion loss.

[0052] In addition, as shown in Figures 3 and 4, the base plate 105 may further include a notch forming portion 140 that is provided between either one of the one-side thickness forming panel 120 and the other-side thickness forming panel 130 (in one embodiment of the present invention, the other-side thickness forming panel 130 is used) and the body upper forming panel 150, and is extended horizontally (or in the thickness direction) within the cavity C.

[0053] As shown in FIGS. 3 and 4, the notch forming portion 140 may be provided integrally with the base plate 105 and in the form of a panel that is positioned inside the cavity C during the folding process.

[0054] However, the notch forming portion 140 is not necessarily limited to being formed integrally with the base plate 105 and constructed by a folding process, but may also be manufactured as a separate panel and constructed in a manner that corresponds to the base plate 105 or is joined to the inside of the cavity C, as shown in Figures 7 to 9 described below.

[0055] Furthermore, it goes without saying that the notch forming portion 140 does not necessarily have to be provided in the form of a panel, but can also be formed integrally with the portion corresponding to the body upper forming panel 150, to the extent that the shape can be deformed inside the cavity C by the worker who will perform frequency tuning later.

[0056] Here, the notch forming portion 140 can include an L-notch portion 141 that forms a notch (hereinafter referred to as an "L-notch") due to inductive coupling at the right end (high frequency region) of the pass band, and a C-notch portion 143 that forms a notch (hereinafter referred to as a "C-notch") due to capacitive coupling at the left end (low frequency region) of the pass band.

[0057] The positions and shapes of the L-notch portion 141 and the C-notch portion 143 and the principles of forming the L-notch and the C-notch will be described in more detail with reference to various embodiments described later.

[0058] As shown in Figures 3 and 4, when the notch forming portion 140 is provided simultaneously with the body upper forming panel 150, one side separation panel 151 and the other side separation panel 152 that separate the notch forming portion 140 and the body upper forming panel 150 in the thickness direction may be further provided integrally with the base plate 105, and after separating them by a predetermined distance using a folding operation, the lower end of the one side separation panel 151 and the lower end of the other side separation panel 151 can be butt-welded to each other externally using this as a connecting line.

[0059] Meanwhile, the upper body forming panel 150 can be integrally cut to have a plurality of frequency tuning bars (see reference numeral 146 in Figures 7 and 8 described later) for fine frequency tuning by adjusting the distance between the plurality of resonators 170 arranged inside the cavity C to form a single layer in the thickness direction, and a plurality of coupling adjustment bars (see reference numeral 147 in Figures 7 and 8 described later) that are respectively deformed in shape and located directly below the plurality of resonators 170.

[0060] Here, the plurality of frequency tuning bars 146 and the plurality of coupling adjustment bars 147 can be integrally formed together with the L-notch portion 141 and the C-notch portion 143 on a tuning frame (not shown) in which the notch forming portion 140 is formed.

[0061] More specifically, the tuning frame is formed in the form of a frame having a rectangular frame, and a plurality of tuning bars 146 are formed extending from the inside of one long side of the four sides of the tuning frame to the other long side, and each may be spaced a predetermined distance apart in the longitudinal direction.

[0062] In addition, the multiple coupling adjustment bars 147 may be formed integrally with the tuning frame and, like the multiple tuning bars 146, extend from the inside of one long side to the other long side, and each may be provided in the space between the multiple tuning bars 146.

[0063] Meanwhile, L-notch portion 141 and C-notch portion 143 may be formed to extend from the inside of the other long side of the four sides (four sides) of the tuning frame toward one long side.

[0064] Here, it goes without saying that the tuning frame forms the same layer within the cavity C, whereas the multiple tuning bars 146 and multiple coupling adjustment bars 147 form different layer layers within the cavity C from the multiple resonators 170.

[0065] That is, the multiple tuning bars 146 may be arranged in a single layer different from the multiple resonators 170 arranged in the cavity C so that the separation distance between the multiple tuning bars 146 and the multiple resonators 170 arranged in the cavity C can be adjusted.

[0066] Furthermore, it goes without saying that tool insertion holes (not shown) can be formed through the upper body forming panel 150 from top to bottom so that the above-mentioned L-notch portion 141 and C-notch portion 143 can be deformed using a predetermined tool.

[0067] Here, as shown in Figures 2 to 6, assuming that the cavity C generated by folding each part of the base plate 105 is formed into a slim rectangular parallelepiped shape that is long in the longitudinal direction and whose size in the vertical thickness direction is relatively very small compared to the front-to-back width direction, the multiple resonators 170 may be arranged to form the same single layer in the thickness direction of the cavity C.

[0068] In addition, the notch forming portion 140 may also be provided so as to form the same single layer in the thickness direction of the cavity C, but to form a single layer different from the plurality of resonators 170 described above.

[0069] However, the position and shape of the notch forming portion 140 are not necessarily determined, and it goes without saying that various designs, which will be described later, are possible depending on the position and selection of the resonator related to multi-path coupling.

[0070] FIG. 7 is a plan view illustrating the principle and structure of notch formation in a first embodiment of the filter for a communication device according to one embodiment of the present invention, which uses a notch forming portion; FIG. 8 is an internal perspective view of FIG. 7; FIG. 9 is a circuit diagram of FIG. 7; FIG. 10 is a graph showing the frequency characteristics of FIG. 7; FIG. 11 is a plan view illustrating the principle and structure of notch formation in a second embodiment of the filter for a communication device according to one embodiment of the present invention, which uses a notch forming portion; FIG. 12 is an internal perspective view of FIG. 11; FIG. 13 is a circuit diagram of FIG. 11; 15 is a plan view illustrating the notch formation principle and structure of a third embodiment of the filter for a communication device according to an embodiment of the present invention, which uses a notch forming portion; FIG. 16 is an internal perspective view of FIG. 15; FIG. 17 is a circuit diagram of FIG. 15; FIG. 18 is a graph showing the frequency characteristics of FIG. 15; FIG. 19 is a plan view illustrating the notch formation principle and structure of a fourth embodiment of the filter for a communication device according to an embodiment of the present invention, which uses a notch forming portion; FIG. 20 is an internal perspective view of FIG. 19; and FIG. 21 is a graph showing the frequency characteristics of FIG. 19.

[0071] Generally, to improve the stopband attenuation characteristics of a Band Pass Filter (BPF), a transmission-zero design is used using electric coupling, magnetic coupling, or mixed coupling between non-adjacent odd number (cascaded triplet) or even number (cascaded quadruplet) of resonant elements (resonators).

[0072] Cross coupling across an even number of resonant elements generally results in symmetrical transmission zeros in the filter passband, while cross coupling across an odd number of resonant elements generally results in a single transmission zero on the left or right side of the passband depending on the type of coupling (i.e., electric or magnetic coupling).

[0073] The transmission zeros that occur on the left side of the passband or symmetrically on the left and right sides using electric field coupling are called capacitive cross-coupling, and the transmission zeros that occur on the right side of the passband using magnetic field coupling are called inductive cross-coupling.

[0074] Generally, in the absence of a separate notch structure, coupling occurs predominantly as magnetic coupling between adjacent resonator elements, whereas capacitive cross-coupling in a cavity filter is achieved by artificially providing the separate notch structure described above.

[0075] Among the components of filter 100 for a communication device according to one embodiment of the present invention, notch forming portion 140 functions as the above-mentioned notch structure. In particular, in the present invention, a plurality of resonators 170 are provided so as to form the same layer in the thickness direction of cavity C and are arranged in a row in the longitudinal direction of cavity C at a predetermined distance apart, thereby solving the problem of how difficult it is to design a notch structure serving as notch forming portion 140.

[0076] More specifically, as shown in Figures 7 to 21, in filters 100A to 100D for communication devices according to one embodiment of the present invention, when the input port portion 175A, the output port portion 175B and the multiple resonators 170 (1 surrounded by a circle: written as circle 1) to 170 (circle 7) are defined as "resonant elements", the notch forming portion 140 can be designed to be arranged so that it is relatively closer than the separation distance between the portions where magnetic field coupling or electric field coupling is dominant of each of the adjacent resonant elements among at least three or more adjacent resonant elements selected sequentially along the longitudinal direction of the cavity C for multipath coupling, thereby forming predetermined notches at the left and right ends of the passband to limit the filtering frequency range.

[0077] 7 and 8, the resonators 170, excluding the input port portion 175A and the output port portion 175B among the resonant elements, may be formed so that the tip portion corresponding to the other end in the width direction is divided into a resonant end 173, which is a portion where electric field coupling is dominant (hereinafter referred to as the "electric field portion") and has a larger longitudinal size than other portions where magnetic field coupling is relatively dominant (hereinafter referred to as the "magnetic field portion").

[0078] Here, the notch forming portion 140 may include an L-notch portion 141 formed adjacent to each other so that the entire portion only affects the magnetic field portion, and a C-notch portion 143 formed adjacent to each other so that a portion of each portion only affects the electric field portion.

[0079] However, it should be noted that whether the notch structure provided in cavity C is defined as L-notch portion 141 or C-notch portion 143 is not necessarily defined simply in relation to whether they are physically adjacent to each other. This will be explained in more detail later.

[0080] Meanwhile, the notch forming portion 140 may function as a cross-coupling bar that couples across at least one or more of the plurality of resonators 170 sequentially arranged in the longitudinal direction of the cavity C.

[0081] Referring to FIG. 7, the C-notch portion 143 starts from a position close to the resonator 170 (circle 2) located relatively close to the first input stage side, crosses the adjacent resonator 170 (circle 3), and extends to a position close to the resonator 170 (circle 4) located relatively close to the first output stage side, thereby serving to cross-couple the second resonator 170 (circle 2) and the fourth resonator 170 (circle 4).

[0082] Similarly, the L-notch section 141 starts from a position close to the resonator 170 (circle 5) located relatively close to the input first stage side, crosses the adjacent resonator 170 (circle 6), and extends to a position close to the resonator 170 (circle 7) located relatively close to the output first stage side, thereby serving to cross-couple the fifth resonator 170 (circle 5) and the seventh resonator 170 (circle 7).

[0083] As shown in FIGS. 7 and 8 , the notch forming portion 140 realized in the first embodiment of the configuration of the filter 100A for a communication device according to one embodiment of the present invention is such that the L-notch portion 141 is arranged to form a layer layer different from the layer layer formed by the resonators 170 in the thickness direction of the cavity C and is provided to form a closed loop extending from one widthwise side of the cavity C to the other widthwise side, and the C-notch portion 143 is arranged to form a layer layer different from the layer layer formed by the resonators 170 in the thickness direction of the cavity C and extends from one widthwise side of the cavity C to the other widthwise side, and may be provided relatively adjacent to any one of the resonant ends 173 of the multiple resonators 170.

[0084] Here, it is preferable that the extension tip of the L-notch portion 141 forms a closed loop within the magnetic field region as much as possible, and it is preferable that the tip of the C-notch portion is formed adjacent to the resonant end 173 of the resonator to be coupled (for example, the fourth resonator 170 (circle 4)).

[0085] The principle of forming notches at both the left and right ends of the passband by the notch forming unit 140 according to the first embodiment will be briefly described below with reference to the accompanying FIGS.

[0086] When a signal is input from the input port 175A on one side of the cavity C, in each resonator 170, magnetic field coupling (L-coupling) predominates in the body 171 up to the resonant end 173, which is the tip of the resonator, and electric field coupling (C-coupling) predominates at the resonant end 173, so that two coupling properties exist simultaneously.

[0087] In addition, when adjacent coupling occurs between each resonant element (i.e., input port portion 175A, output port portion 175B and resonator 170), the coupling properties can be determined by the notch structure (notch forming portion 140) additionally provided in cavity C, and therefore definitions can also be made regarding each structure of notch forming portion 140.

[0088] More specifically, as shown in Figures 9 and 10, adjacent coupling occurs between the second resonator 170 (circle 2) and the third resonator 170 (circle 3) and between the third resonator 170 (circle 3) and the fourth resonator 170 (circle 4), and it can be seen from the circuit diagram in Figure 9 that magnetic field coupling generally prevails between each resonator 170, resulting in inductive coupling.

[0089] At the same time, the second resonator 170 (circle 2) and the fourth resonator 170 (circle 4) are cross-coupled by the C-notch portion 143, but in this case, it can be seen that capacitive coupling occurs because electric field coupling is dominant due to the extended tip of the C-notch portion 143.

[0090] On the other hand, as shown in Figures 9 and 10, adjacent coupling and inductive coupling also occur between the fifth resonator 170 (circle 5) and the sixth resonator 170 (circle 6) and between the sixth resonator 170 (circle 6) and the seventh resonator 170 (circle 7), and cross-coupling occurs between the fifth resonator 170 (circle 5) and the seventh resonator 170 (circle 7) due to the L-notch portion 141. In this case, it can be seen that inductive coupling occurs in that the closed loop of the L-notch portion 141 is formed adjacent to a magnetic field portion where magnetic field coupling is dominant.

[0091] Therefore, as shown in FIG. 10, when the notch forming section 140 realized in the first embodiment is used, a C-notch (left end) and an L-notch (right end) are formed at the left and right ends of the passband, respectively, making it possible to ensure the frequency characteristics desired by the designer.

[0092] Meanwhile, in the configuration of the filter 100A for a communication device according to one embodiment of the present invention, the notch forming portion 140 realized in the second embodiment may be defined as either the L-notch portion 141 or the C-notch portion 143, as shown in Figures 11 and 12, depending on the properties of the electric field portion and the magnetic field portion that are relatively strongly expressed due to adjacent coupling or cross coupling among the multiple resonators 170.

[0093] That is, the C-notch portion 143 of the notch forming portion 140 realized in the second embodiment has a structure that cross-couples the second resonator 170 (circle 2) and the fourth resonator 170 (circle 4), like the first embodiment, but its shape differs from that of the notch forming portion 140 of the first embodiment in that it is configured to form a closed loop within the magnetic field portion range, like the L-notch portion 141.

[0094] Nevertheless, as shown in Figures 11 to 14, the C-notch portion 143 of the notch forming portion 140 realized in the second embodiment is configured so that the separation distance L2 between the resonance ends 173 of the adjacently coupled third resonator 170 (circled 3) and fourth resonator 170 (circled 4) is closer than the separation distance L1 between the resonance ends 173 of other resonators (e.g., the second resonator 170 (circled 2) and the third resonator 170 (circled 3)). In this case, the notch forming portion 140 that cross-couples the second resonator 170 (circled 2) and the fourth resonator 170 (circled 4) can be defined by the C-notch portion 143.

[0095] Similarly, in the L-notch portion 141 of the notch forming portion 140 realized in the second embodiment, an L-notch due to inductive coupling is formed at the right end of the passband in that inductive coupling (magnetic field coupling) is more dominant than the capacitive coupling (electric field coupling) between the adjacently coupled fifth resonator 170 (circle 5) and sixth resonator 170 (circle 6) and between the sixth resonator 170 (circle 6) and seventh resonator 170 (circle 7). In this case, the notch forming portion 140 that cross-couples the fifth resonator 170 (circle 5) and the seventh resonator 170 (circle 7) can be defined by the L-notch portion 141.

[0096] However, the above-described method of defining the L-notch portion 141 and the C-notch portion 143 is limited to the case where each notch forming portion 140 is provided within the range of the resonator 170 (for example, within another range in the longitudinal direction of the cavity C).

[0097] As shown in Figures 15 to 18, when the L-notch portion 141 and the C-notch portion 143 are provided in a single configuration in the same range in the longitudinal direction of the cavity C, a composite configuration may be defined that simultaneously has the functions of the L-notch portion 141 and the C-notch portion 143 due to the properties due to adjacent coupling and the properties due to cross coupling among the multiple resonators 170.

[0098] More specifically, referring to Figures 15 and 16, the notch forming portion 140 is formed to start from a portion adjacent to the second resonator 170 (circle 2) among the plurality of resonators 170, and extend across the third resonator 170 (circle 3) and the fourth resonator 170 (circle 4) to a portion adjacent to the fifth resonator 170 (circle 5) while forming a closed loop, thereby serving to cross-couple the second resonator 170 (circle 2) and the fifth resonator 170 (circle 5).

[0099] In this case, the notch forming portion 140 functions as an inductive coupling in that it cross-couples across an even number of resonators 170, while the separation distance L2 between the resonant ends 173 of the third resonator 170 (circle 3) and the fourth resonator 170 (circle 4), which are adjacently coupled and located within the notch forming portion 140, is closer than the separation distance L1 between the other resonators, so that electric field coupling predominates and the notch forming portion 140 functions as a capacitive coupling. Therefore, it is preferable that the notch forming portion 140 is not only defined by the L-notch portion 141 but also by a composite configuration including the C-notch portion 143.

[0100] According to the notch forming section 140 realized in the third embodiment configured as described above, a C-notch and an L-notch are formed at the left and right ends of the passband, respectively, as shown in FIG. 18, thereby enabling the frequency characteristics required by the designer to be realized.

[0101] A communication device filter 100D according to an embodiment of the present invention discloses the following notch formation principle by means of a notch forming portion 140 realized in the fourth embodiment as shown in FIGS.

[0102] That is, assuming that the input port portion 175A and the output port portion 175B are included as coupled resonating elements, the C-notch portion 143 may be formed to branch from the input port portion 175A and extend across the one-side end resonator (i.e., the first resonator 170 (circle 1)) toward the resonating end 173 of the adjacent resonator (i.e., the second resonator 170 (circle 2)).

[0103] Also, under the same process, the L-notch portion 141 may be formed so as to branch from the output port portion 175B and connect to the adjacent resonator (i.e., the sixth resonator 170 (circle 6)) across the other side end resonator (i.e., the seventh resonator 170 (circle 7)).

[0104] Here, when a signal is input through the input port portion 175A, the C-notch portion 143 realizes capacitive coupling between the second resonator 170 (circle 2) skipping the first resonator 170 (circle 1) at the time of the signal input stage, and when a signal is output through the output port portion 175B, the L-notch portion 141 realizes inductive coupling between the sixth resonator 170 (circle 6) and the output port portion 175B skipping the seventh resonator 170 (circle 7) at the end point of the signal output stage.

[0105] In this case, the tip of the C-notch portion 143 may extend to form a layer different in thickness from the second resonator 170 (circle 2), and may be positioned so as not to be directly connected to the second resonator 170 (circle 2).

[0106] In addition, it is preferable that the starting end of the L-notch portion 141 is directly connected to the sixth resonator 170 (circle 6), and a window wall 145 that functions like a partition wall of a general cavity filter may be further provided between the sixth resonator 170 (circle 6) and the seventh resonator 170 (circle 7).

[0107] The window wall 145 is formed to extend through the thickness direction of the mutually spaced apart portions between the sixth resonator 170 (circle 6) and the seventh resonator 170 (circle 7), and the widthwise tip at one side end of the cavity C can extend to a position that partially restricts the magnetic field coupling between the sixth resonator 170 (circle 6) and the seventh resonator 170 (circle 7).

[0108] According to the notch forming unit 140 realized in the fourth embodiment as described above, it can be seen that a C-notch and an L-notch are formed at the left and right ends of the passband, respectively, as shown in FIG. 21.

[0109] In this way, filters 100, 100A to 100D for communication devices according to one embodiment of the present invention form cavity C by folding base plate 105, and use simpler and more useful notch forming portion 140 inside a slim filter body with a small thickness, thereby providing the advantage that the frequency characteristics desired by the designer can be secured.

[0110] Although all components constituting the embodiments of the present invention have been described as being combined together to operate, the present invention is not necessarily limited to such an embodiment, and all components may be selectively combined with one or more other components to operate depending on the embodiment within the scope of the present invention.

[0111] The above description is merely an example of the technical concept of the present invention, and various modifications and variations may be made by a person having ordinary knowledge in the technical field to which the present invention pertains without departing from the essential characteristics of the present invention. [Industrial Applicability]

[0112] The present invention provides a filter for communications equipment that forms a cavity using a folding method and constructs a notch-forming section with a simple and easy configuration inside a filter that is somewhat small in size in the thickness direction, thereby ensuring a variety of frequency characteristics and making it easy to design notches on both sides of the passband. [Explanation of symbols]

[0113] 100: Filter for communication equipment, 105: Base plate 110: Body bottom forming panel, 120: One side thickness forming panel 130: other side thickness forming panel, 140: notch forming portion 141: L-notch section, 143: C-notch section 145: Partition wall configuration, 150: Body upper forming panel 170: Resonator, 175A: Input port section 175B: Output port, C: Cavity

Claims

1. When the radiation direction of the antenna element is defined as the front-to-rear direction, a base plate having a thickness in the front-to-rear direction that is at least smaller than the width in the left-to-right direction and forming a hexahedral cavity with the vertical direction as the longitudinal direction; a plurality of resonators each having the same layer structure in the front-to-back direction (thickness direction) of the cavity; an input port unit for inputting a predetermined signal to one of the plurality of resonators at one end closest to one end of the cavity in the longitudinal direction, and an output port unit for outputting a predetermined signal from one of the plurality of resonators at the other end closest to the other end of the cavity in the longitudinal direction, a notch forming portion disposed within the cavity so as to be relatively closer than a separation distance between portions of adjacent resonance elements, each of which has a dominant magnetic field coupling or a dominant electric field coupling, of the plurality of resonance elements.

2. 2. The filter for a communication device according to claim 1, wherein the plurality of resonators of the resonance element excluding the input port portion and the output port portion are each formed so as to have a resonant end at a tip portion corresponding to the other end in the width direction in the left-right direction, the resonant end being a portion where the electric field coupling is dominant (hereinafter referred to as an "electric field portion") that is larger in size in the longitudinal direction than other portions where the magnetic field coupling is relatively dominant (hereinafter referred to as a "magnetic field portion").

3. 3. The filter for a communication device according to claim 2, wherein the notch-forming portion includes an L-notch portion formed adjacent to the notch portion so that the entire notch portion affects only the magnetic field portion, and a C-notch portion formed adjacent to the notch portion so that either part of the L-notch portion affects the electric field portion.

4. 4. The filter for a communication device according to claim 3, wherein the L-notch portion and the C-notch portion function as cross-coupling bars that couple across at least one or more of the plurality of resonators sequentially arranged in the longitudinal direction.

5. 4. The filter for a communication device according to claim 3, wherein the L-notch portion and the C-notch portion are arranged so as to form the same layer in the thickness direction within the cavity, and so as to form a layer different from that of the plurality of resonators.

6. 6. The filter for a communication device according to claim 5, wherein the L-notch portion is provided so as to form a closed loop extending from one widthwise side of the cavity to the other widthwise side.

7. 6. The filter for a communication device according to claim 5, wherein the C-notch portion extends from one widthwise side of the cavity to the other widthwise side and is provided relatively adjacent to any one of the resonance ends of the plurality of resonators.

8. 6. The filter for a communication device according to claim 5, wherein the L-notch portion is disposed relatively closer than a separation distance between electric field portions of adjacent resonant elements among at least three or more adjacent resonant elements sequentially selected along the longitudinal direction for multipath coupling, thereby forming a predetermined notch at a right end of a passband and limiting a filtering frequency range.

9. 6. The filter for a communication device according to claim 5, wherein the C-notch portions are arranged relatively closer than a separation distance between magnetic field portions of adjacent resonant elements among at least three or more adjacent resonant elements sequentially selected along the longitudinal direction for multipath coupling, thereby forming a predetermined notch at a left end of a passband and limiting a filtering frequency range.

10. The L-notch portion and the C-notch portion are 6. The filter for a communication device according to claim 5, wherein the filter is defined as either an L-notch portion or a C-notch portion depending on the properties of the electric field portion and the magnetic field portion that are relatively strongly expressed due to adjacent coupling or the cross-coupling among the plurality of resonators.

11. 11. The filter for a communication device according to claim 10, wherein when the L-notch portion and the C-notch portion are provided in different ranges in the longitudinal direction of the cavity, the plurality of resonators are defined as either the L-notch portion or the C-notch portion depending on the properties of the electric field portion and the magnetic field portion.

12. 6. The filter for a communication device according to claim 5, wherein when the L-notch portion and the C-notch portion are provided in a single configuration in the same range in the longitudinal direction of the cavity, the filter is defined as a composite configuration that simultaneously has the functions of the L-notch portion and the C-notch portion due to properties due to adjacent coupling and properties due to cross coupling among the plurality of resonators.

13. When the input port section and the output port section are included as the coupled resonant elements, 6. The filter for a communication device according to claim 5, wherein the C-notch portion is formed so as to branch from the input port portion, cross the one-side end resonator, and extend toward the resonant end of the adjacent resonator.

14. When the input port section and the output port section are included as the coupled resonant elements, 6. The filter for a communication device according to claim 5, wherein the L-notch portion branches from the output port portion, crosses the other-side end resonator, and is connected to an adjacent resonator.

15. 2. The filter for a communication device according to claim 1, wherein the cavity is formed by folding the single base plate.

16. 16. The filter for a communication device according to claim 15, wherein the notch forming portion is manufactured as a separate panel and is joined to a structure corresponding to the base plate or to the inside of the cavity.

17. 16. The filter for a communication device according to claim 15, wherein the notch forming portion is provided integrally with the base plate and in the form of a panel that is located inside the cavity when the filter is folded.

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