KR20090021775A - Frequency tunable filter - Google Patents

Abstract

A frequency tunable filter capable of performing tuning of a plurality of resonators at the same time is provided to secure wide tuning range by forming a bottom surface of a metal tuning element and a top surface of a resonator into a tapered shape. A frequency tunable filter comprises a resonator(408), a sliding member(414), a metal tuning element(430), and a ground member. The resonator is loaded on a cavity. The metal tuning element is coupled in a bottom of the sliding member corresponding to the resonator. At least one among a top surface of the resonator and a bottom surface of the metal tuning element has a tapered shape. A tapered direction of the bottom surface of the metal tuning element is identical or is different to a tapered direction of the top surface of the resonator. The ground member is positioned on a top of the sliding member, and is contacted with the metal tuning element.

Description

Frequency Tunable Filter

The present invention relates to a filter, and more particularly, to a tunable filter capable of varying filter characteristics such as the center frequency and bandwidth of the filter.

A filter is a device for passing only a signal of a specific frequency band among input frequency signals, and has been implemented in various forms. The band pass frequency of the RF filter is determined by the inductance component and the capacitance component of the filter, and the operation of adjusting the band pass frequency of the filter is called tuning.

In a communication system such as a mobile communication system, operators are allocated an arbitrary frequency band and divide the allocated frequency band into several channels. In the conventional case, telecommunication operators used to separately prepare filters for each frequency band.

However, in recent years, as the communication environment changes rapidly, it is necessary to change characteristics such as the center frequency and the bandwidth, unlike the initial environment in which the filter is mounted. Tunable filters are used to vary these characteristics.

1 is a view showing the structure of a conventional tunable filter.

Referring to FIG. 1, a conventional tunable filter includes a housing 100, an input connector 102, an output connector 104, a cover 106, a plurality of cavities 108, and a resonator 110.

The RF filter is a device for passing only a signal of a specific frequency band among input frequency signals, and has been implemented in various formats.

A plurality of walls are formed inside the filter, and the cavity 108 defines a cavity 108 in which each resonator is accommodated. The cover 106 is provided with a coupling hole and a tuning bolt 112 for coupling the housing 100 and the cover 106.

The tuning bolt 112 is coupled to the cover 106 and penetrates into the housing. The tuning bolt 112 is disposed in the cover 106 corresponding to a position corresponding to the resonator or a predetermined position inside the cavity.

The RF signal is input by the input connector 102 and output to the output connector 104, and the RF signal proceeds through coupling windows formed in each cavity. A resonance phenomenon of the RF signal is generated by each cavity 108 and the resonator 110, and the RF signal is filtered by the resonance phenomenon.

In the conventional tunable filter as shown in FIG. 1, tuning for frequency and bandwidth is performed by a tuning bolt.

2 is a cross-sectional view of one cavity in a conventional tunable filter.

2, the tuning bolt 112 is penetrated from the cover 106 and positioned above the resonator. The tuning bolt 112 is made of a metal material and is fixed by screwing the cover.

Therefore, the tuning bolt 112 may be adjusted by the distance between the resonator and the tuning by varying the distance between the resonator 110 and the tuning bolt 112. The tuning bolts 112 may be rotated by hand, or a separate tuning machine for the rotation of the tuning bolts may be used. The tuning bolts are held by the nuts if the tuning is done in the proper position.

3 is a view for explaining the principle that tuning is performed by the rotation of the tuning bolt.

Referring to FIG. 3, a capacitance C is formed between the tuning bolt and the resonator. Capacitance is a physical quantity that varies by permittivity, cross-sectional area, and distance between two metals, the distance corresponding to the distance between the tuning bolt and the resonator.

That is, the capacitance is also changed by changing the distance between the tuning bolt and the resonator by the rotation of the tuning bolt. Capacitance is one parameter that determines the frequency of the filter, and the center frequency of the filter may be changed by changing the capacitance.

The conventional tunable filter as described above has the following problems.

First, there is a problem that takes a considerable time when tuning is made by hand. Manual tuning requires turning the tuning bolts one by one, which required considerable time.

Secondly, when a plurality of resonators are provided, there is a problem in that they must be tuned individually. In particular, when tuning is performed by hand, the tuning of the tuning bolts corresponding to the plurality of resonators has to be done manually. Therefore, the work is cumbersome and takes a considerable time, which is a factor of increasing the manufacturing cost.

Third, the tuning bolt has a problem that it is difficult to properly fix it after the tuning is made at a predetermined position. In case of tuning by the conventional rotation method, the position between the tuning bolt and the resonator should be fixed after it is set. There was a problem in that the tuning was twisted by the fine tuning of the tuning bolt in the fixing work. It should be provided.

Fourth, the tuning by the conventional tuning bolt had a problem that it is difficult to secure a wide tuning range due to power problems. As described above, tuning by the tuning bolts is performed by adjusting the distance between the resonator and the tuning bolts. If this distance is not sufficiently secured, tuning cannot be performed in the desired tuning range. In particular, when the distance between the tuning bolt and the resonator is close to the power problem occurs, which acted as a major factor that can not secure a wide tuning range in the conventional filter. In recent years, the miniaturization of the filter is continuously required, and the smaller the filter, the more difficult it is to secure a wide tuning range when using tuning by a tuning bolt.

The present invention proposes a sliding frequency tunable filter which can be tuned in a plurality of resonators in order to solve the problems of the prior art as described above.

Another object of the present invention is to propose a frequency tunable filter which can reduce tuning time and reduce manufacturing cost.

Still another object of the present invention is to propose a slidable tunable filter having a wider tuning range.

In order to achieve the above object, according to an aspect of the present invention, a tunable filter using the sliding of the sliding member, the resonator accommodated in a plurality of cavities; And a metal tuning element coupled to the lower part of the sliding member corresponding to the resonator and provided on the resonator, wherein at least one of the upper part of the resonator and the lower part of the tuning element is provided with a frequency tunable filter.

The taper direction formed below the metal tuning element and the taper direction formed above the resonator may be the same.

The taper direction formed below the metal tuning element and the taper direction formed above the resonator may be opposite to each other.

When there are a plurality of metal tuning elements, the taper angles for at least some of the plurality of metal tuning elements are different.

A ground member for providing a ground voltage to the metal tuning element is coupled to the upper portion of the sliding member, and the ground member may be electrically coupled to the metal tuning element.

The ground member is in electrical contact with the cover of the filter.

The present invention can be tuned to a plurality of resonators collectively, there is an advantage that can reduce the tuning time and manufacturing cost.

 In addition, according to the present invention, it is possible to secure a wide tuning range, there is an advantage that the tuning state can be easily fixed after tuning.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the frequency tunable filter according to the present invention.

4 is an exploded perspective view of a frequency tunable filter according to an embodiment of the present invention.

Referring to FIG. 4, a frequency tunable filter according to an embodiment of the present invention includes a housing 400, a cover 402, a tuning bolt 404, a plurality of cavities 406, a plurality of resonators 408, and an input. Metal tuning element 416 coupled to connector 410, output connector 412, sliding member 414, and sliding member 414.

The housing 400 protects components such as a resonator inside the filter and serves as a shield for electromagnetic waves. The housing 400 may be a housing formed by forming a base of aluminum and silver plated thereto. RF equipment such as filters and waveguides typically use silver plating with excellent electrical conductivity to minimize losses. In recent years, in addition to improving properties such as corrosion resistance, plating methods other than silver plating may be used, and housings using such plating methods may be used.

The cover 402 is coupled to the housing at the top of the housing, and may be coupled to the housing by screwing through a plurality of fastening holes (not shown). The cover 402 is formed with a hole for the tuning bolt 404 through which the tuning bolt 404 penetrates into the housing from the cover. Since the thread is formed in the hole, the depth through which the tuning bolt 404 penetrates by rotation may vary.

The position at which the tuning bolt 404 is coupled to the cover corresponds to the position of the resonator 408 inside the filter. In general, the tuning bolt 404 is set in the cover to correspond to the center position of the resonator, but according to one embodiment of the present invention so as to correspond to the position offset by a predetermined distance from the center of the resonator, not the center of the resonator It is preferable to install. Of course, the position of the tuning bolt is not limited to the above-described embodiment, and may be installed so as to correspond to the center of the resonator as in the prior art, and with respect to the position of the tuning bolt 404 in addition to the description of the tuning sliding bar later. Explain.

The embodiment of the present invention proposes tuning by a sliding method, and the tuning bolt 404 may be omitted. However, the initial tuning is performed by the tuning bolt 404 at the time of initial tuning by the filter manufacturer, and the tuning by the user may be performed by a sliding method to be described later, the tuning by the tuning bolt 404 and a sliding method to be described later. Tuning by may also be used together. In addition, when the two types of tuning are used together, the tuning range can be extended.

The tuning bolt 404 can be adjusted in distance from the resonator 408 by rotation as in the prior art, both mechanical and manual rotation is possible. The tuning bolt 404 may be fixed in distance to the resonator 408 via a nut or other various known fastening means after the tuning is completed.

A plurality of partitions are formed inside the filter, which define the cavity in which the resonators 408 are accommodated together with the housing 400 of the filter. The number of cavities and resonators is associated with the order of the filter, and FIG. 4 shows the case of order 8, i.e., eight resonators. The order of the filter is associated with insertion loss and skirt characteristics. The higher the order of the filter, the higher the skirt characteristics but the lower the insertion loss trade-off relationship. The order of the filter is set by the required insertion loss and skirt characteristics. Although a disk-type resonator is illustrated in FIG. 4, various types of resonators, such as a cylindrical resonator, may be used.

Some of the barrier ribs have coupling windows corresponding to the propagation directions of the RF signal. The RF signal resonating by the cavity and the resonator proceeds through the coupling window to the next cavity.

A sliding member 414 is provided between the cover and the resonator 408. The sliding member 414 is provided to be slidable in a direction perpendicular to the direction in which the resonator stands, that is, in a horizontal direction. The sliding member 414 may be slid in an automated manner using a motor and may be slid by a user by hand. The installation structure of the sliding member 414 will be described in detail with reference to the separate drawings.

The sliding member 414 may be supported by the partition walls formed in the filter and the jaw 450 formed at the end of the filter.

The number of sliding members 414 may correspond to the number of resonator lines formed in the filter. 4 shows a filter having two resonator lines in which four resonators are distributed in each line, and the number of sliding members 414 may correspond to two.

A metal tuning element 430 is coupled to each sliding member 414. The metal tuning element 430 is coupled to the sliding member 414 corresponding to the position of the resonator opposite the sliding member 414.

In FIG. 4, there are four resonators at the bottom of one sliding member, so that four metal elements are coupled to one sliding member. The spacing of the metal elements to be joined also corresponds to the spacing between the resonators.

The sliding member 414 to which the metal tuning element 430 is coupled is used for tuning the filter. As described above, the tuning of the conventional filter used a tuning bolt. The tuning of the rotation method by the tuning bolt is not only troublesome to tune, but also requires a lot of time due to individual tuning.

According to the exemplary embodiment of the present invention, the tuning is performed by the sliding member to which the metal tuning element 430 is coupled, so that simple and collective tuning is possible.

The position of the coupled metal tuning element 430 corresponding to the sliding of the sliding member 414 is also varied. The metal tuning element 430 forms capacitance by interaction with the resonator 408, and the capacitance changes when the position of the metal tuning element 430 changes.

That is, by varying the positional relationship between the metal tuning element and the resonator, the capacitance can be changed to tune the frequency.

When there are a plurality of sliding members, the sliding members may be independently slid and may be collectively slid by one motor. In case of sliding in a lump, all the resonators of the filter can be tuned in a lump, and even if they are slid independently, the tuning efficiency is significantly increased compared to the tuning by a conventional tuning bolt.

5 is a perspective view of a sliding member according to an embodiment of the present invention, FIG. 6 is a bottom plan view of a sliding member according to an embodiment of the present invention, and FIG. 7 is a cross-sectional view of the sliding member according to an embodiment of the present invention. 8 is a top plan view of a sliding member according to an embodiment of the present invention.

5 to 8, the metal tuning elements 430 are coupled to the sliding member at predetermined intervals, and as described above, the intervals of the metal tuning elements correspond to the intervals between the resonators.

 By implementing the tuning element with a metal material, the capacitance value is determined by the distance between the resonator 408 and the metal tuning element 430 and the area where the resonator 408 and the metal tuning element 430 overlap.

Referring to FIG. 6, the shape of the metal tuning element 430 is a shape in which a corner is cut at a rectangle. The shape of the metal tuning element 430 may be rectangular or circular and may be set in various forms.

Preferably, the thickness of the metal tuning element 430 is relatively thin, and the width of the metal tuning element 430 is preferably wider than the width of the sliding member so that as much of the resonator can overlap as possible.

5 to 8, two coupling holes 500 and 502 are formed at one end of the sliding member. The coupling holes 500 and 502 are coupling holes for engaging with the driving unit that is slid by the motor when the sliding member 414 is slid by the motor. Coupling relationship between the sliding member and the motor will be described later through separate drawings, and the driving unit and the sliding member may be coupled through the coupling holes 500 and 502. According to one embodiment of the invention, the coupling holes (500, 502) is formed with a screw thread, the sliding member may be coupled by screw coupling.

The other end of the sliding member 414 need not be formed with a hole, and can be installed in the filter only so as to be able to hang on a specific structure so as to be freely slidable. For example, a method of forming a jaw to which the sliding member can be worn at the end of the filter can be used.

A plurality of long holes 504, 506, 508, 510 are formed in the sliding member 414. The long holes 504, 506, 508, 510 are holes formed for free tuning of the tuning bolts when the tuning bolts are tuned together with the sliding members. If the holes 504, 506, 508, 510, 512 are not formed when the tuning bolt is penetrated, it is blocked by the sliding member, so that the holes for preventing the sliding bolt are formed.

The plurality of long holes 504, 506, 508, 510, 512 are set in correspondence with the positions of the tuning bolts penetrated from the cover. Since the spacing of the tuning bolts corresponds to the spacing between the resonators, the spacing of the long holes may correspond to the spacing of the resonators and the spacing of the metal tuning elements 430. Of course, the spacing between the long holes 504, 506, 508, 510, the resonator 408, and the metal tuning element 430 may be set independently of each other.

If the holes 504, 506, 508, 510, 512 are not formed when the tuning bolt is penetrated, it is blocked by the sliding member, so that the holes for preventing the sliding bolt are formed.

The long holes 504, 506, 508, 510, 512 are in the form of long holes that are not circular, corresponding to the size of the tuning bolts, so that they are not affected by the tuning bolts passing through the holes when the sliding member slides. That is, the length of the long holes 504, 506, 508, 510, 512 is determined by the sliding range of the sliding member 414.

Referring to FIG. 7, the ground member 520 is coupled to the upper portion of the sliding member 414. The number of grounding members 520 and the position of the grounding member 520 correspond to the metal tuning element 430. Preferably, grounding member 520 is coupled to the opposite position of metal tuning element 430.

Ground member 520 is electrically coupled with metal tuning element 430 and provides a ground potential to the metal tuning element. Ground member 520 is in electrical contact with a cover having a ground potential, such that metal tuning element 430 may maintain a ground potential.

According to one embodiment of the invention, the ground member 520 and the metal tuning element 430 are electrically coupled by screwing. 7 and 8, the sliding member is formed with a hole for screwing the ground member 420 and the metal tuning element 430, and the metal tuning element 430 and the ground member 520 through the hole. Screw connection is made. Referring to FIG. 8, a case in which the ground member 520 and the metal tuning element 430 are coupled by two screws 530 and 532 is illustrated.

When tuning with varying capacitance, the capacitance is varied by cross-sectional area, distance and dielectric constant. The present invention relates to an embodiment in which the dielectric constant is fixed but the capacitance is varied by changing the cross-sectional area and distance, wherein the metal material generating capacitance in response to the resonator needs to have a ground potential.

In the exemplary embodiment of the present invention, the ground member 520 is installed on the sliding member to which the metal tuning element 430 is coupled, and the ground member 520 and the metal tuning element 430 are coupled to provide the ground potential. Therefore, according to the embodiment of the present invention, even if metal is used as the tuning element coupled to the sliding member, it is possible to form a stable capacitance and to change the capacitance.

As described above, the ground member 520 contacts the cover having the ground potential, and the sliding action of the sliding member 414 may be affected by the friction force in contact with the cover.

According to the embodiment of the present invention, even if the grounding member 520 contacts the cover, a structure capable of minimizing the inhibition of the sliding operation due to the frictional force is proposed.

5 to 8, the ground member 520 is implemented in the form of a leaf spring. Referring to FIG. 8, the ground member 520 has a leaf spring structure in which a plurality of wings 520a having elastic force are formed.

The wing 520a is in electrical contact with the lower part of the cover, and has an elastic force, thus stably contacting the lower part of the cover.

9 and 10 are views illustrating a contact state between a cover and a grounding member according to an exemplary embodiment of the present invention.

9 and 10, the end of the wing 520a having an elastic force contacts the bottom of the cover of the filter. Since only the end of the wing portion having a relatively small area is in contact with the lower portion of the cover, the frictional force of the sliding member when sliding can be minimized.

In addition, since the wing 520a has an elastic force, the lower part of the cover and the ground member maintain a stable contact state during the sliding operation even when contact is made for a small area.

8 shows the ground member having eight wings 520a formed therein, the size and number of the wings may vary according to the structure of the filter.

Meanwhile, referring to FIG. 9, a guide groove 900 corresponding to the sliding member is formed under the cover. When there are a plurality of sliding members, the guide groove 900 may be formed corresponding to each sliding member. The sliding member is inserted into the guide groove 900 to slide.

The guide groove 900 functions to guide the sliding member to move only in a predetermined sliding direction and not to move in another direction when the sliding member moves. In order to reduce the overall volume of the filter, the case where the guide means is formed in the groove is shown in FIG. 9, and the present invention is not limited to the guide being formed by the groove.

11 is a view showing the insertion state of the guide groove and the sliding member according to an embodiment of the present invention.

Referring to FIG. 11, the width of the guide groove 900 corresponds to the width of the sliding member 414 so that a suitable guide can be made, and the depth of the guide groove also corresponds to the thickness of the sliding member 414.

When there are a plurality of sliding members, the lower portion of the cover alternately repeats the region where the guide groove is formed and the region that is not formed. As shown in FIG. 11, the metal tuning element 430 coupled to the sliding member 414 is wider than the sliding member 414, whereby the metal tuning element 430 is formed with a guide groove in the cover. Not to cause friction with the area.

In order to prevent such friction, according to an embodiment of the present invention, a thin anti-friction groove 1100 is formed in a region where the guide groove is not formed in the lower portion of the cover corresponding to the position of the metal tuning element.

Since the anti-friction groove 1100 is to prevent friction between the metal tuning element 430 and the bottom of the cover, the anti-friction groove 1100 is preferably formed as thin as possible. In addition, the length of the anti-friction groove 1100 is set corresponding to the sliding range of the sliding member 414. As shown in FIG. 11, the anti-friction groove 1100 is formed long so that friction does not occur even when the sliding member 414 is slid.

12 is a cross-sectional view of one cavity of a tunable filter according to an embodiment of the present invention.

Referring to FIG. 12, one cavity is provided with a resonator 408. The resonator may be fixed to the bottom of the filter by screwing. As described above, although a disc shaped resonator is illustrated in FIG. 12, the shape of the resonator may be variously changed.

A sliding member 414 is placed on the resonator. The tuning bolt 404 penetrates through the long hole of the sliding member 414. Typically the tuning bolt is penetrated into the center of the resonator but in FIG. 12 it is penetrated from a position slightly to the right of the resonator.

As described above, the tuning bolt 404 is slightly penetrated to the right from the center of the resonator in consideration of the sliding range of the metal tuning element 430. If the metal tuning element 430 is slidable to the center position of the resonator, the tuning bolt may be a barrier, so that the tuning bolt is slightly biased to the right. If the sliding of the metal tuning element 430 is not a problem, the tuning bolt may pass through the center of the resonator.

In addition, as described above, the tuning bolt is not provided, and the tuning by the sliding member 414 alone is also possible. When the tuning bolts are provided together, the tuning bolts may be used only for initial tuning or may be used for tuning with the sliding member 414 after the initial setting.

As the sliding member 414 slides, the metal tuning element 430 coupled thereto also slides. As the metal tuning element moves, the range where the upper portion of the resonator and the metal tuning element overlap is changed, thereby changing the capacitance value whose cross-sectional area is a parameter.

In FIG. 12, when the sliding member is slid to the right, the cross-sectional area generating capacitance between the metal tuning element 430 and the resonator 408 will increase, thereby increasing the capacitance.

FIG. 13 illustrates a cross-sectional view of one cavity of a tunable filter according to another embodiment of the present invention. FIG.

Referring to FIG. 13, unlike the metal tuning element illustrated in FIGS. 4 to 12, the metal tuning element 430 of FIG. 13 has a shape in which a bottom surface of the metal tuning element 430 opposite to the resonator is tapered at an angle. In addition, the upper surface of the resonator is also tapered at a predetermined angle.

FIG. 13 illustrates a case in which the taper shapes of the metal tuning element and the resonator are the same, but the pattern shape may be changed. For example, the bottom surface of the metal tuning element may taper from top to bottom while the top surface of the resonator may taper from top to bottom. In addition, the angle of the taper may also be variously set. In addition, embodiments in which only the metal tuning element and the resonator are tapered will be included in the scope of the present invention.

Thus, the taper on the metal tuning element 430 and the resonator 408 is to ensure a wider tuning range. In the conventional tuning by the tuning bolt, the tuning range is determined by the distance that can be secured between the resonator and the tuning bolt, and when the filter having a low height is required, the tuning range is inevitably limited.

When a tunable filter using a sliding method is used in an embodiment of the present invention, it is possible to secure a wider tuning range than a conventional tuning bolt. However, when the shapes of the metal tuning element and the resonator are changed as shown in FIG. It can be secured.

In order to secure a wide tuning range, it is necessary to take a large amount of capacitance change. When a slope is formed in the metal tuning element 430 and the resonator 408 as shown in FIG. 13, the distance is changed as well as the cross-sectional area, thereby changing the capacitance amount more. This allows a wider tuning range.

14 is a cross-sectional view of a cavity of one of the tunable filters according to another embodiment of the present invention.

Referring to FIG. 14, a taper is formed in the shape of a truncated cone on the resonator. When the taper is formed in such a structure, the taper may be more easily formed, thereby reducing the manufacturing cost.

The structure shown in FIG. 14 is also a structure for maximizing a tuning range, and resonators and metal tuning elements having various structures using the structures of FIGS. 13 and 14 may be included in the scope of the present invention.

FIG. 15 shows a change in capacitance when using a tapered metal tuning element and a resonator and when using a flat metal tuning element and a resonator, and FIG. 16 shows a flat tuning when using a tapered metal tuning element and a resonator. It is a figure which shows the resonant frequency change when using an element and a resonator.

Referring to FIG. 15, when the taper-formed metal tuning element and the resonator are used, it can be confirmed that the capacitance change rate is large. Referring to FIG. 16, the resonant frequency change rate also corresponds to the capacitance change rate. If you use a resonator, you can see that it is larger.

17 and 18 are views illustrating a coupling relationship between a sliding member and a driving unit sliding the sliding member according to an embodiment of the present invention.

Referring to FIG. 17, the driving unit includes a motor 1700, a screw 1702 coupled to the motor, and an intermediate member 1704 coupled to the screw 1702.

Motor 1700 provides rotational force, and rotational force of motor 1700 is provided to screw 1702. The screw 1702 converts the rotational movement of the motor 1700 into a horizontal movement. The intermediate member 1704 is formed with a screw hole for coupling the screw 1702, the intermediate member 1704 moves in the horizontal direction of the left and right corresponding to the rotation of the screw 1702.

A coupling hole 1706 is formed at the upper portion of the intermediate member 1704 to engage the sliding member 414. The coupling hole 1706 formed on the upper portion of the intermediate member corresponds to the coupling hole formed at one end of the sliding member, and two holes are formed with threads so that the intermediate member 1704 and the sliding member 414 are formed by screwing. Can be combined. Of course, the coupling method is not limited to screw coupling, and various coupling methods may be used.

 One end of the sliding member 414 is engaged with the intermediate member 1704 but the other end is not fixed for free sliding. For example, referring to FIG. 4, the other end of the sliding member 414 may span the jaw 450 formed in the filter, wherein the jaw is preferably formed in consideration of the sliding range of the sliding member 414. .

The driving unit as described above may be built in the filter, or may be provided outside. When provided on the outside, a part of the sliding member may protrude to the outside and be coupled with the intermediate member of the driving unit.

1 is a view showing the structure of a conventional tunable filter.

2 is a cross-sectional view of one cavity in a conventional tunable filter.

3 is a view for explaining the principle that tuning is performed by the rotation of the tuning bolt.

4 is an exploded perspective view of a frequency tunable filter according to an embodiment of the present invention.

5 is a perspective view of a sliding member according to an embodiment of the present invention.

6 is a bottom plan view of the sliding member according to an embodiment of the present invention.

7 is a cross-sectional view of the sliding member according to an embodiment of the present invention.

8 is a top plan view of the sliding member according to an embodiment of the present invention.

9 and 10 are views showing a contact state of the cover and the ground member according to an embodiment of the present invention.

11 is a view showing the insertion state of the guide groove and the sliding member according to an embodiment of the present invention.

12 is a cross-sectional view of a cavity of one of the tunable filters according to an embodiment of the present invention.

13 is a cross-sectional view of a cavity of one of the tunable filters according to another embodiment of the present invention.

14 is a cross-sectional view of a cavity of one of the tunable filters according to another embodiment of the present invention.

FIG. 15 shows capacitance changes when using a tapered metal tuning element and a resonator and when using a flat metal tuning element and a resonator. FIG.

FIG. 16 is a diagram showing a change in resonant frequency when using a tapered metal tuning element and a resonator and when using a flat tuning element and a resonator. FIG.

17 and 18 are views illustrating a coupling relationship between a sliding member and a driving unit sliding the sliding member according to an embodiment of the present invention.

Claims (8)

As a tunable filter using the sliding of the sliding member, A resonator housed in a plurality of cavities; And A metal tuning element coupled to the lower portion of the sliding member corresponding to the resonator and provided on the resonator, And at least one of an upper portion of the resonator and a lower portion of the tuning element is formed with a taper. The method of claim 1, And a taper direction formed below the metal tuning element and a taper direction formed above the resonator. The method of claim 1, And a taper direction formed below the metal tuning element and a taper direction formed above the resonator. The method of claim 1, And the taper angle for at least some of the plurality of metal tuning elements is different when the metal tuning elements are plural. The method of claim 1, And when the plurality of resonators is provided, the taper angles of at least some of the plurality of resonators are different. The method of claim 1, The top of the resonator is a frequency tunable filter is tapered to form a truncated cone. The method of claim 1, And a grounding member for providing a ground voltage to the metal tuning element at an upper portion of the sliding member, wherein the grounding member is electrically coupled with the metal tuning element. The method of claim 9, And the grounding member is in electrical contact with the cover of the filter.

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