KR101250628B1 - Multi mode filter for tuning coupling value - Google Patents

Abstract

Disclosed is a multi-mode filter capable of tuning coupling values while implementing wideband. The multi-mode filter is located between a housing member, a first cavity and a second cavity formed in the housing member, a first resonator housed in the first cavity, a second resonator housed in the second cavity, and between the cavities. And a partition wall, a first coupling element, and at least one tuning element to separate the cavities. Here, a groove is formed between the housing member and the partition wall, the first coupling element is inserted into the groove in a direction crossing the partition wall, and a portion of the first coupling element is in the first cavity. Another portion of the first coupling element is arranged in the second cavity, and the tuning element is arranged to face the first coupling element in a state accommodated in at least one of the cavities.

Description

MULTI MODE FILTER FOR TUNING COUPLING VALUE}

The present invention is directed to a multimode filter that realizes sufficient coupling in a multimode.

The conventional multi-mode filter performs coupling between resonators by arranging a coupling element in a coupling window formed in the partition wall.

Such a coupling structure could sufficiently implement a desired coupling value in a single mode, but not a sufficient coupling value in multiple modes. As a result, conventional multi-mode filters operated only with narrowband filters.

In addition, once the multimode filter was manufactured, there was no longer a way to tune the coupling values.

The present invention provides a multi-mode filter capable of tuning a coupling value while implementing a wide bandwidth.

In order to achieve the above object, the multi-mode filter according to an embodiment of the present invention comprises a housing member; A first cavity and a second cavity formed in the housing member; A first resonator accommodated in the first cavity; A second resonator accommodated in the second cavity; A partition wall disposed between the cavities to separate the cavities; And a first coupling element; And at least one tuning element. Here, a groove is formed between the housing member and the partition wall, the first coupling element is inserted into the groove in a direction crossing the partition wall, and a portion of the first coupling element is in the first cavity. Another portion of the first coupling element is arranged in the second cavity, and the tuning element is arranged to face the first coupling element in a state accommodated in at least one of the cavities.

" 형상을 가지고, 상기 커플링 엘리먼트 중 좌측 절곡 부분은 상기 제 1 캐비티 내에 배열되며, 상기 커플링 엘리먼트 중 우측 절곡 부분은 상기 제 2 캐비티 내에 배열되고, 상기 커플링 엘리먼트와 상기 제 1 공진기 사이에는 E 필드 커플링과 H 필드 커플링이 모두 발생하며, 상기 튜닝 엘리먼트는 상기 캐비티들 중 적어도 하나에 수용된 상태로 상기 커플링 엘리먼트와 마주보도록 배열된다. According to another embodiment of the present invention, a multi-mode filter includes a housing member; A first cavity and a second cavity formed in the housing member; A first resonator accommodated in the first cavity; A second resonator accommodated in the second cavity; Coupling elements; And at least one tuning element. Here, the coupling element is "

", Wherein the left bent portion of the coupling element is arranged in the first cavity, the right bent portion of the coupling element is arranged in the second cavity, and between the coupling element and the first resonator Both E field coupling and H field coupling occur, and the tuning element is arranged to face the coupling element in a state accommodated in at least one of the cavities.

" 형상의 커플링 엘리먼트를 설치하고 상기 커플링 엘리먼트를 캐비티들에 수용되도록 배열하며, 그 결과 해당 공진기와 커플링 엘리먼트 사이에 E-필드 커플링 및 H-필드 커플링이 모두 발생된다. 따라서, 공진기들 사이의 커플링 값이 증가하며, 그 결과 상기 다중 모드 필터는 광대역을 구현할 수 있다. The multi-mode filter according to the invention has a groove in the groove between the housing member and the partition wall.

Install a coupling element of the shape and arrange the coupling element to be received in the cavities, resulting in both E-field coupling and H-field coupling between the resonator and the coupling element. The coupling value between the resonators is increased, and as a result, the multi-mode filter can realize wideband.

In addition, since the width and height of the coupling element may be variously modified, the coupling element may be implemented in various structures. As a result, the multi-mode filter can appropriately design the coupling element according to its purpose to achieve the desired coupling value.

In addition, the multi-mode filter can tune the desired coupling value by installing a tuning element at a position facing the coupling element and adjusting the coupling value using the tuning element. In particular, the tuning element compensates for the difference in coupling values due to mechanical errors that may occur in a multi-mode filter in which the coupling element is fixed to the bottom surface of the housing member with a metal screw to achieve a desired coupling value. Can be.

1 is a perspective view showing a multi-mode filter according to a first embodiment of the present invention.
FIG. 2 is a plan view illustrating the multi-mode filter of FIG. 1.
3 is a perspective view illustrating a coupling element and a tuning element according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating insertion loss according to an entry depth of a tuning element in a multi-mode filter according to an embodiment of the present invention.
5 is a perspective view showing a multi-mode filter according to a second embodiment of the present invention.

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

1 is a perspective view illustrating a multi-mode filter according to a first embodiment of the present invention, and FIG. 2 is a plan view illustrating the multi-mode filter of FIG. 1. 3 is a perspective view illustrating a coupling element and a tuning element according to an embodiment of the present invention. However, in FIG. 1B, some components of the multi-mode filter are omitted in order to display an accurate arrangement of the tuning elements 140 and 142.

Referring to FIG. 1, the multi-mode filter of the present embodiment uses a multi-mode filter and is capable of tuning a coupling value, and includes a housing member 100, a cover 101, a first cavity 102, and a first cavity. Second cavity 104, first resonator 106, second resonator 108, partition 110, first coupling element 114, second coupling element 122, fixing member 124, first A first tuning element 140 and a second tuning element 142.

The housing member 100 protects components such as the resonators 106 and 108 inside the multi-mode filter and shields electromagnetic waves. The housing member 100 may be formed by, for example, plating silver having high conductivity on an aluminum material, and serves as an electrical ground.

The cover 101 is coupled to an upper portion of the housing member 100, and may be coupled to an upper surface of the housing member 100 by, for example, bolting. The cover 101 may also be formed by, for example, plating silver on an aluminum material, and serves as an electrical ground.

The cavities 102 and 104 are spaces formed in the multi-mode filter for frequency resonance, and are defined by the partition wall 110. Although FIG. 1 illustrates that the cavity 102 or 104 has a cylindrical shape, the cavity 102 or 104 may have various shapes such as, for example, a rectangular parallelepiped shape.

The first resonator 106 is housed in the first cavity 102 and the second resonator 108 is housed in the second cavity 104. The resonators 106 and 108 may be cylindrical resonators as shown in FIG. 1A, but various types of resonators such as a disc type resonator may be used. The material of the resonators 106 and 108 may be a metal resonator or a dielectric resonator, depending on the mode of the RF filter (TE mode or TM mode).

According to one embodiment of the invention, the first resonator 106 intersects, for example, orthogonal to the first mode 130 and the first mode 130 as shown in FIGS. 1A and 2. A second mode 132 may be generated. In addition, two modes may occur in the second resonator 108, that is, a third mode corresponding to the first mode 130 and a fourth mode corresponding to the second mode 132. Of course, although only two modes are shown for one resonator in FIGS. 1 and 2, three or more modes may occur. In addition, a plurality of modes may occur on the top and bottom surfaces of the resonators 106 and 108.

According to one embodiment of the invention, the resonators 106 or 108 may have a relatively low height, i.e. a flat cylindrical shape, so that the modes 130, 132, etc. may each be in a HEH mode. Of course, the modes 130, 132, etc. may be other types of modes depending on the shape of the resonators 106, 108. For example, if the resonators 106 or 108 have a relatively high height, the modes may be HEE modes, respectively.

Hereinafter, the modes 130 and 132 will be assumed to be HEH modes, respectively.

In the multi-mode filter, fields are generated on the upper and lower surfaces of the resonator 106 or 108, respectively. Therefore, in order to adjust the coupling between the resonators 106 and 108, the fields of the upper and lower surfaces of the resonator 106 or 108 must be controlled. However, in the HEH mode, the fields on the upper surface of the resonator 106 or 108 dominate the coupling between the resonators 106 and 108, and the influence of the fields on the lower surface is less. Accordingly, the coupling between the resonators 106 and 108 may be adjusted by controlling the fields of the upper surface of the resonator 106 or 108.

According to one embodiment of the present invention, as shown in FIG. 1, a groove 112 may be formed between the housing member 100 and the partition wall 110, and the groove 112 may include the cavities 102 and 104. It is formed to be interconnected.

The first coupling element 114 is arranged in the cavities 102 and 104 with the groove 112 inserted.

According to one embodiment of the invention, the first coupling element 114 is a metal, as shown in FIG. 3, the first coupling part 300, the second coupling part 302, and the third coupling part 304. The fourth coupling part 306 and the fifth coupling part 308 may be included.

The first coupling part 300 is inserted into the groove 112 between the housing member 100 and the partition wall 110 and may have a structure whose length is considerably longer than the height. The first coupling part 300 may be fixed by the fixing member 124. Specifically, the fixing member 124 supports and holds the first coupling part 300 in a state of being fixed to the housing member 100 and the partition wall 110.

The second coupling part 302 extends from the first coupling part 300 in a direction perpendicular to the first coupling part 300 and is accommodated in the first cavity 102. In this case, the second coupling part 302 may be arranged spaced apart from the inner surface corresponding to the first cavity 102 of the housing member 100 or may contact the inner surface.

The third coupling part 304 extends from the first coupling part 300 in a direction perpendicular to the first coupling part 300 and is accommodated in the second cavity 104. In this case, the third coupling part 304 may be arranged to be spaced apart from the inner surface corresponding to the second cavity 104 of the housing member 100 or may contact the inner surface. In addition, the third coupling unit 304 may be symmetrically arranged with the second coupling unit 302 based on the first coupling unit 300.

The fourth coupling part 306 extends from the second coupling part 302 in a direction perpendicular to the second coupling part 302, and the bottom surface of the housing member 100 corresponding to the first cavity 102. Can be put on. As a result, the first coupling element 114 is grounded.

The fifth coupling part 308 extends from the third coupling part 304 in a direction perpendicular to the third coupling part 304 and the bottom surface of the housing member 100 corresponding to the second cavity 104. Can be put on. As a result, the first coupling element 114 is grounded.

According to an embodiment of the present invention, the fourth coupling part 306 and the fifth coupling part 308 may be fixed to the bottom surface of the housing member 100 by using a metal screw. In this case, since the first coupling element 114 is stably fixed to the bottom surface of the housing member 100 through the metal screw, the fixing member 124 may not be present.

" 형상을 가지며, 하우징 부재(100)와 전기적으로 연결되어 접지된다. That is, the first coupling element 114 as a whole is "

Have a shape and are electrically connected to the housing member 100 and grounded.

From an electrical point of view, an E-field coupling 310 and an H-field coupling 312 occur between the second coupling portion 302 and the first resonator 106. Of course, E-field coupling and H-field coupling also occur between the third coupling portion 304 and the second resonator 108. Here, the E-field coupling corresponds to capacitive coupling, and the H-field coupling corresponds to inductive coupling.

According to an embodiment of the present invention, the multi-mode filter adjusts the capacitive coupling by adjusting the area of the second coupling part 302 or the area of the third coupling part 304, and the second coupling part 304. Height) or the height of the third coupling portion 304 is adjusted to adjust the inductive coupling. That is, the multi-mode filter may adjust the coupling value between the resonators 106 and 108 by adjusting the size or height of the second coupling unit 302 or the third coupling unit 304.

1 and 3, the second coupling part 302 and the third coupling part 304 are symmetrically arranged and have the same size, but the second coupling part 302 and the third coupling part 304 are shown. May be arranged asymmetrically or have a different size. For example, the width of the second coupling portion 302 and the width of the third coupling portion 304 may be different. That is, the multi-mode filter may implement various coupling values by appropriately setting the width or height of the second coupling unit 302 and the third coupling unit 304.

Referring to FIG. 1 again, the partition wall 110 may be provided with a groove 120 (coupling window), and the second coupling element 122 may be arranged through the coupling window 120. However, since the coupling value between the resonators 106 and 108 may be sufficiently implemented using the first coupling element 114, the partition 110 does not have a coupling window or the second coupling element 122 may be formed. It may not exist.

The first tuning element 140 may be a metal bolt, for example, and is received into the first cavity 102 in a state coupled to the cover 101 as shown in FIG. 1B. However, the first tuning element 140 does not contact the bottom surface of the housing member 100.

According to one embodiment of the invention, the first tuning element 140 may be arranged between the inner side of the housing member 100 corresponding to the first coupling element 114 and the first cavity 102. In particular, the first tuning element 140 may be arranged at a position directly facing the second coupling portion 302 of the first coupling element 114. Of course, the first tuning element 140 may also be arranged between the first coupling element 114 and the first resonator 106, but in terms of coupling efficiency, the first coupling element 114 and the housing member 100. It is preferably arranged on the inner side of the).

Arranging the first tuning element 140 on the inner side of the first coupling element 114 and the housing member 100 as described above, the capacitive coupling is small and the inductive coupling is maintained, the overall coupling value Will increase.

If a multi-mode filter is implemented in a structure that fixes the first coupling element 114 to the bottom surface of the housing member 100, mechanical tolerances may occur. Although the desired coupling value may not be realized due to such mechanical tolerances, the multi-mode filter of the present invention may compensate for the difference in coupling values due to such mechanical tolerances using the first tuning element 140. . That is, the multi-mode filter of the present invention can always achieve the desired coupling value using the first tuning element 140 regardless of the mechanical tolerance.

According to an embodiment of the present invention, the first tuning element 140 may move up and down in engagement with the cover 101 as shown in FIG. 1B to tune the coupling value. In the actual tuning process, the coupling value is adjusted by moving the first tuning element 140 up and down, and when the coupling value is adjusted to a desired value, the first tuning element 140 is fixed at the corresponding position.

The second tuning element 142 may be a metal bolt, for example, and is received into the second cavity 104 in a state coupled to the cover 101 as shown in FIG. 1B. The tuning element 142 is not in contact with the bottom surface of the housing member 100.

According to one embodiment of the invention, the second tuning element 142 may be arranged between the inner side of the housing member 100 corresponding to the first coupling element 114 and the second cavity 104. In particular, the second tuning element 142 may be arranged in a position directly facing the third coupling portion 304 of the first coupling element 114. Of course, the second tuning element 142 may be arranged between the first coupling element 114 and the second resonator 108.

The second tuning element 142 may have the same size while being symmetrically arranged around the first tuning element 140 and the partition wall 110. In addition, the second tuning element 142 may move up and down while being coupled to the cover 101 as shown in FIG. 1B to tune the coupling value.

According to another embodiment of the present invention, the tuning elements 140 and 142 may have different sizes. For example, the tuning elements 140 and 142 may have the same cylindrical shape, but the radius of the first tuning element 140 may be greater than the radius of the second tuning element 142.

In summary, the multi-mode filter of this embodiment controls the coupling between the resonators 106 and 108 using the first coupling element 114 and the coupling value using the tuning elements 140 and 142. You can tune to the desired value.

In the above, one tuning element 140 or 142 is accommodated in each cavity 102 and 104, but a tuning element may only be accommodated in some cavity 102 or 104 and a plurality of tunings in cavity 102 or 104. Elements may be accommodated.

Hereinafter, the multimode filter of the present invention and the conventional dual mode filter will be compared.

In the conventional dual mode filter, only the capacitive coupling by the E-field is adjusted through the coupling window, and as a result, the coupling value cannot be sufficiently realized in the dual mode filter.

On the other hand, the multi-mode filter of the present invention adjusts the coupling value between the resonators 106 and 108 using both capacitive coupling by the E-field and inductive coupling by the H-field. As a result, the multi-mode filter of this embodiment can realize a sufficient coupling value. In particular, since the first coupling element 114 may be structurally modified in various forms, and the coupling value may be tuned using the tuning elements 140 and 142, the multi-mode filter may adjust various coupling values as desired. It can be realized.

In addition, since the first coupling element 114 is fixed to the bottom surface of the housing member 100 by a metal screw, even if an external shock such as vibration, extreme temperature change, shock, etc. occurs, the bottom surface of the housing member 100. It can be stably fixed at. Therefore, deterioration of the characteristics of the multi-mode filter due to external impact may not occur. However, although the method of implementing the first coupling element 114 may cause mechanical tolerance, the multi-mode filter of the present invention uses the tuning elements 140 and 142 to compensate for the coupling difference according to the mechanical tolerance. To compensate.

Hereinafter, the experimental results of the multi-mode filter of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a diagram illustrating insertion loss according to an entry depth of a tuning element in a multi-mode filter according to an embodiment of the present invention. Specifically, FIG. 4 shows the insertion loss waveform 400 when the entry depth (accommodation depth) of the tuning element into the corresponding cavity is 0 mm and the insertion loss waveform 402 when the entry depth is 5 mm. .

Referring to the insertion loss waveforms 400 and 402 of FIG. 4, the bandwidth of the insertion loss waveform 402 when the entry depth is 5 mm in the band where the loss is approximately 0 is 0 mm (entry depth). It can be seen that the width of the insertion loss waveform 400 at the time. That is, it can be seen that tuning of the bandwidth is possible by adjusting the entry depth of the tuning element, and in FIG. 4, it is confirmed that bandwidth tuning (that is, coupling) of about 8 MHz is possible.

Although not shown in the drawings, it has been confirmed that the conventional dual mode filter implements a narrow band of 0.89% having a bandwidth of 23 MHz at a center frequency of 2.56 kHz. This is because there is not enough coupling between the resonators.

On the other hand, the multi-mode filter of the present invention was confirmed that the bandwidth is implemented to be larger than 23MHz at the center frequency of 2.56 kHz. That is, the multi-mode filter of the present invention can implement a wide bandwidth. This is because the multi-mode filter has realized sufficient coupling between resonators 106 and 108 using both capacitive coupling by E-field and inductive coupling by H-field.

5 is a perspective view showing a multi-mode filter according to a second embodiment of the present invention.

Referring to FIG. 5, the multi-mode filter of the present embodiment includes a housing member 500, a first cavity 502, a second cavity 504, a first resonator 506, a second resonator 508, and a partition 510. ), A first coupling element 514, a second coupling element 516, a first tuning element 530, and a second tuning element 532.

Since the remaining components except for the first coupling element 514 are the same as in the first embodiment, detailed description of the same components will be omitted below.

" 형상을 가지며, 제 1 커플링부(520), 제 2 커플링부(522) 및 제 3 커플링부(524)를 포함한다. The first coupling element 514 is generally "

It has a shape, and includes a first coupling part 520, a second coupling part 522, and a third coupling part 524.

The first coupling part 520 is inserted into the groove 512 between the housing member 500 and the partition wall 510. Although not shown, the first coupling part 520 is fixed by the fixing member as in the first embodiment, and is physically separated from the housing member 500.

The second coupling part 522 extends from the first coupling part 520 in a direction perpendicular to the first coupling part 520 and is accommodated in the first cavity 502. Here, the second coupling part 522 is physically separated from the bottom and side surfaces of the housing member 500.

The third coupling part 524 extends from the first coupling part 520 in a direction perpendicular to the first coupling part 520 and is received in the second cavity 504. Here, the third coupling part 524 is physically separated from the bottom and side surfaces of the housing member 500.

That is, the first coupling element 514 is received in the cavities 502 and 504 in an electrically open state. In this case, as in the first embodiment, both the E-field coupling and the H-field coupling occur, so that the coupling between the resonators 506 and 508 can be made sufficiently.

In addition, since the first coupling element 514 can be modified into various structures, the multi-mode filter of the present embodiment can implement various coupling values.

According to an embodiment of the present invention, the first tuning element 530 may be located behind the second coupling part 522 in a state accommodated in the first cavity 502, and the second tuning element 532 may be It may be located behind the third coupling part 524 in a state accommodated in the second cavity 504.

" 형상의 커플링 엘리먼트를 이용하여 다중 모드를 위한 커플링 값을 충분하게 실현하고, 상기 커플링 엘리먼트의 넓이 및 높이를 조절하여 커플링 값을 다양하게 실현할 수 있다. 여기서, 상기 커플링 엘리먼트는 단락 형태 또는 개방 형태를 가질 수 있다. In summary, the multi-mode filter of the present invention is housed in cavities with a groove inserted between the housing member and the partition wall.

Coupling values for multiple modes can be sufficiently realized using coupling elements of the "shape, and the coupling values can be realized in various ways by adjusting the width and height of the coupling elements. It may have a short form or an open form.

In addition, it is possible to tune the coupling value between the coupling element and the inner side of the housing member corresponding to the cavity, regardless of whether the coupling element is short-circuited or open.

The embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

100 housing member 102 first cavity
104: second cavity 106: first resonator
108: second resonator 112: groove
114: first coupling element 120: coupling window
122: second coupling element 124: fixing member
130: first mode 132: second mode
140: first tuning element 142: second tuning element
500 housing member 502 first cavity
504: second cavity 506: first resonator
508: second resonator 510: partition wall
512 groove 514 first coupling element
516: second coupling element 520: first coupling portion
522: second coupling portion 524: third coupling portion
530: first tuning element 532: second tuning element

Claims (8)

In a multimode filter,
A housing member;
A first cavity and a second cavity formed in the housing member;
A first resonator accommodated in the first cavity;
A second resonator accommodated in the second cavity;
A partition wall disposed between the cavities to separate the cavities;
A first coupling element; And
At least one tuning element,
A groove is formed between the housing member and the partition wall, the first coupling element is inserted into the groove in a direction crossing the partition wall, and a portion of the first coupling element is arranged in the first cavity; And another portion of the first coupling element is arranged in the second cavity, the tuning element corresponding to the first coupling element and the at least one cavity, with the tuning element received in at least one of the cavities. And face the first coupling element between inner surfaces of the housing member. The method of claim 1, wherein the multi-mode filter,
Further comprising a cover covering the housing member,
A first tuning element of the tuning elements is arranged in the first cavity coupled to the cover, a second tuning element of the tuning elements is arranged in the second cavity coupled to the cover, And the tuning elements are movable up and down while being coupled to the cover. 3. The method of claim 2, wherein the first coupling element is "

"Having a shape and coupling between said resonators using both E field coupling and H field coupling. The method of claim 3, wherein the first coupling element,
A first coupling part inserted into the groove;
A second coupling part extending in length from the first coupling part in a direction perpendicular to the first coupling part and accommodated in the first cavity;
A third coupling part extending in length from the first coupling part in a direction perpendicular to the first coupling part and received into the second cavity;
A fourth coupling part extending in length from the second coupling part in a direction perpendicular to the second coupling part and electrically connected to a bottom surface of the housing member corresponding to the first cavity; And
A fifth coupling part extending in length from the third coupling part in a direction perpendicular to the third coupling part and electrically connected to a bottom surface of the housing member corresponding to the second cavity;
The fourth coupling portion and the fifth coupling portion are connected via a metal screw to the bottom surface of the housing member which is grounded, and the first tuning element is connected to the housing portion corresponding to the second coupling portion and the first cavity. And a second tuning element arranged between an inner side of a housing member corresponding to the third coupling portion and the second cavity. The method of claim 3, wherein the first coupling element,
A first coupling part inserted into the groove;
A second coupling part extending in length from the first coupling part in a direction perpendicular to the first coupling part and accommodated in the first cavity; And
A third coupling part extending in length from the first coupling part in a direction perpendicular to the first coupling part and received into the second cavity;
The second coupling portion is arranged between the inner surface and the first resonator in a state in which the second coupling portion is physically separated from the inner surface of the housing member corresponding to the first cavity, and the third coupling portion corresponds to the second cavity. The second coupling part and the third coupling part are arranged between the inner surface and the second resonator in a physically separated state from the inner surface of the housing member, the bottom surface of the housing member corresponding to the cavities And the first tuning element is arranged between the second coupling part and the inner side of the housing member corresponding to the first cavity, and the second tuning element is the third coupling part and the first coupling element. A multi-mode filter, characterized in that arranged between the inner side of the housing member corresponding to the two cavity. 4. The method of claim 3, wherein a coupling window is formed in the middle portion of the partition wall, a second coupling element is inserted into the coupling window, and one end of the second coupling element is arranged in the first cavity. And the other end of the second coupling element is arranged in the second cavity. In a multimode filter,
A housing member;
A first cavity and a second cavity formed in the housing member;
A first resonator accommodated in the first cavity;
A second resonator accommodated in the second cavity;
Coupling elements; And
At least one tuning element,
The coupling element is "

", Wherein the left bent portion of the coupling element is arranged in the first cavity, the right bent portion of the coupling element is arranged in the second cavity, and between the coupling element and the first resonator Wherein both E field coupling and H field coupling occur, wherein the tuning element is arranged to face the coupling element in a state accommodated in at least one of the cavities. The method of claim 7, wherein the multi-mode filter,
Further comprising a cover covering the housing member,
A first tuning element of the tuning elements is arranged in the first cavity coupled to the cover, a second tuning element of the tuning elements is arranged in the second cavity coupled to the cover, The first tuning element is arranged between the first coupling element and the inner side of the housing member corresponding to the first cavity, and the second tuning element corresponds to the first coupling element and the second cavity. Arranged between the inner side of the housing member, wherein the tuning elements are movable up and down in engagement with the cover, the tuning elements varying the H field coupling.

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