KR101009276B1 - Tunable filter with stable sliding structure - Google Patents

Abstract

PURPOSE: A tunable filter is provided to tune a band pass property by sliding a tuning element through a sliding member. CONSTITUTION: A tunable filter comprises a housing(300), a resonator(308), a cover(302) and a sliding member(304). A plurality of cavities are defined in a housing by partitions. The resonator is received at each cavity. The cover is combined with the housing. The sliding member is mounted on the cover and slides in a first direction. The sliding member is combined with the plurality of tuning elements.

Description

Tunable Filter with Stable Sliding Structure {Tunable Filter with Stable Sliding Structure}

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 by a sliding method.

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 required to change these characteristics.

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

Referring to FIG. 1, a conventional 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 penetrates the hole formed in the cover 106 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 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 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.

A thread is formed in the side of the tuning bolt 112 and the hole into which the tuning bolt is inserted, so that the distance between the resonator and the resonator may be adjusted by rotation, and tuning is performed 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.

In a conventional filter, 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.

Such a conventional filter could be tuned only at the time of initial manufacture, and it was difficult to tune it in use. In order to solve this problem, a tunable filter that can be tuned relatively easily by a sliding method has been proposed.

The slidable tunable filter includes a sliding member that is slidable between the resonators of the filter, and a tuning element of metal or dielectric material is attached to the lower portion of the sliding member, and then the sliding frequency of the sliding member allows the tunable filter to have the same resonant frequency and bandwidth. Tune the properties.

Such a sliding type tunable filter needs a guide structure for stable sliding.

In the present invention, to propose a sliding tunable filter capable of a stable sliding operation.

Other objects of the present invention may be derived by those skilled in the art through the following examples.

According to an aspect of the present invention, a plurality of cavities are defined by the partition walls in order to achieve the object as described above; A resonator accommodated in the cavity; A cover coupled to the upper portion of the housing; And a sliding member that is slidably placed in the first direction on the cover and to which a plurality of tuning elements are coupled, wherein the tuning element is inserted into the filter through a hole formed in the cover and positioned above the resonator. At least one guide hole is formed in the sliding member, and the cover has at least one guide protrusion protruding through the guide hole, and the side surface portion of the guide protrusion is opposed to the guide in a second direction perpendicular to the first direction. A tunable filter with a stable sliding structure in contact with the inner surface of the hole is provided.

The guide hole has a predetermined length in the first direction in consideration of the sliding range of the sliding member.

The tunable filter may further include at least one pressing member for pressing the sliding member at a predetermined pressure.

It is preferable that the said pressing member is a metal body of an elastic material.

The pressing member is coupled to the pressing member supporting portion protruding from the cover to press the sliding member.

The tunable filter further includes a motor accommodating part and a motor provided in the motor accommodating part, wherein the sliding member receives a driving force from the motor.

According to another aspect of the present invention, there is provided a housing comprising: a housing in which a plurality of cavities are defined by partitions; A resonator accommodated in the cavity; A cover coupled to the upper portion of the housing; And a sliding member movably placed on the cover, the sliding element being coupled to a plurality of tuning elements, wherein the tuning element is inserted into the filter through a hole formed in the cover and positioned above the resonator. One guide hole is formed, and the cover has at least one guide protrusion which protrudes through the guide hole, and the stable sliding structure of the sliding motion is guided in a first direction set by the contact of the guide protrusion and the guide hole. A tunable filter is provided.

The hole formed in the cover has a predetermined length in the first direction to allow the tuning element to slide.

The guide hole has a predetermined length in the first direction in consideration of the sliding range of the sliding member.

The guide protrusion has a cylindrical shape, and the diameter of the cross section of the guide protrusion corresponds to the distance between the inner surfaces of the guide hole facing in the second direction perpendicular to the first direction.

The present invention has the advantage that more stable sliding is possible in the tunable filter using a sliding method.

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

3 is an exploded perspective view of a tunable filter having a stable sliding structure according to an embodiment of the present invention.

Referring to FIG. 3, a tunable filter having a stable sliding structure according to an embodiment of the present invention includes a housing 300, a cover 302, a sliding member 304, a plurality of cavities 306, and a plurality of resonators 308. ), An input connector 310, an output connector 312, a motor accommodating part 314, and a motor 316.

The housing 300 protects components such as a resonator inside the filter and serves as a shield for electromagnetic waves. The housing 300 may be a housing in which a base is formed of aluminum and plated thereto. RF equipment such as filters and waveguides typically use silver plating with excellent electrical conductivity to minimize losses. In recent years, a plating method other than silver plating may be used to improve properties such as corrosion resistance, and a housing using such plating method may be used.

The cover 302 is coupled to the housing at the top of the housing, and may be coupled to the housing by, for example, bolting. The cover 302 is also made of metal. Another cover (not shown) for protecting the sliding member 304 and the like and electromagnetically shielding the inside of the filter may be combined and used on the top of the cover 302.

The cover 302 covers the filter part including the cavity and the resonator, but the motor accommodating part 314 is not covered by the cover.

A sliding member 304 is disposed above the cover 302. The sliding member 304 is slidably placed on the cover and slides in the y direction in FIG. 3. At one end of the sliding member 304 placed above the cover 302, a coupling part 380 for coupling with the motor 316 provided in the motor accommodating part 314 is formed to be coupled with the motor, and to rotate the motor. Sliding along.

A plurality of tuning elements 350 are coupled to the sliding member, and the tuning elements 350 are inserted into the filter through holes (not shown in FIG. 3) formed in the cover 302. The tuning element 350 may be made of a metal material or may be made of a dielectric material. The tuning element 350 is slid corresponding to the sliding of the sliding member 304, and the band pass characteristic of the filter is tuned according to the sliding of the tuning element 350. The material of the sliding member is preferably a dielectric. The hole formed in the cover 302 has a predetermined length in consideration of the sliding range in the y direction, which is the sliding direction, to allow sliding of the tuning element.

A plurality of partitions 330 are formed inside the filter, and these partitions define the cavity 306 in which the resonators 308 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.

The input connector 310 is a connector through which an RF signal is input, and the output connector 312 is a connector through which a filtered RF signal is output.

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.

4 is a cross-sectional view of one cavity in the filter illustrated in FIG. 3.

Referring to FIG. 4, a tuning element 350 inserted into the filter is disposed above the resonator 308. In order for the tuning element 350 to be inserted into the filter, a hole 400 is formed in the cover 302. As described above, the hole 400 is formed to have a predetermined length in the sliding direction so that the tuning element is slidable, and the length of the hole 400 is set in consideration of the sliding range. Also, the number of tuning elements 350 corresponds to the number of resonators. The tuning element 350 is coupled to the sliding member 304 to be positioned above the resonator 308 provided in the filter.

When the tuning element 350 slides, tuning of the bandpass characteristic is performed while changing capacitance of the resonator.

When the tuning element 350 is made of a metal material, the capacitance changes as the cross-sectional area between the resonator and the tuning element changes as the position of the tuning element changes, thereby tuning the filter band pass characteristic.

When the tuning element 350 is made of a dielectric material, tuning of the band pass characteristic is performed while the dielectric constant affecting the capacitance is changed while the position of the tuning element 350 is changed.

Although not shown in FIGS. 3 and 4, a tuning bolt for tuning at the time of manufacturing the filter may be inserted into the filter in the cover 302, and the role of the tuning bolt inserted is the same as that of the conventional filter.

5 is a view showing a perspective view of a sliding member used in a tunable filter having a stable sliding structure according to an embodiment of the present invention, Figure 6 is a plan view of a 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.

5 to 7, a plurality of tuning elements 350 are coupled to the sliding member 304, and an installation interval of the tuning elements 350 corresponds to a distance of the resonator 308. In addition, since there are two resonator lines in the filter shown in FIG. 3, the tuning element 350 also includes two lines.

Guide holes 500, 502, 504, and 506 are formed in predetermined portions of the sliding member 304. 5 and 6 illustrate an example in which four guide holes are formed, but the number of guide holes may be appropriately selected by those skilled in the art.

The guide holes 500, 502, 504, and 506 are preferably formed at corner portions of the sliding member, but are not limited thereto.

5 to 7, the tuning element 350 is illustrated in the form of a disc, but the shape of the tuning element may be variously selected.

The tuning element 350 and the sliding member 304 may be coupled through bolting.

8 is a perspective view of a cover coupled state in a tunable filter having a stable sliding structure according to an embodiment of the present invention.

Referring to FIG. 8, a plurality of guide protrusions 800, 802, 804, and 806 are formed in the cover 302, and the guide protrusions 800, 802, 804, and 806 are guide holes 500, 502, 506, and 508. Protrude through).

The shape of the guide protrusions 800, 802, 804, 806 is preferably in the form of a general cylinder. The guide holes 500, 502, 504, 506 are in the form of long holes having a predetermined length in the sliding direction of the sliding member, and the length of the guide holes in the sliding direction is set in consideration of the sliding range.

The guide protrusions 800, 802, 804, 806 are preferably cylindrical in shape and the side portions of the guide protrusions 800, 802, 804, 806 contact the guide holes 500, 502, 504, 506. The side portion of the guide protrusion is in contact with the inner surface of the guide hole perpendicular to the sliding direction of the guide hole. That is, the diameter of the cross section of the guide protrusions 800, 802, 804, 806 corresponds to the length of the hole in the direction perpendicular to the sliding direction.

The guide protrusions 800, 802, 804, and 808 and the guide holes 500, 502, 504, and 506 are guide structures for preventing the sliding member 304 from moving in a direction other than the preset sliding direction during the sliding operation of the sliding member. It works as That is, in FIG. 8, the sliding member slides only in the y direction, and the sliding direction does not deviate from the other direction.

The guide structure using the guide protrusions 800, 802, 804, 808 and the sliding holes 304 formed in the guide protrusions 800, 802, 804, 808 from the cover 302 not only enables stable guiding, The miniaturized structure makes it possible to guide the sliding member.

Meanwhile, each of the guide protrusions 800, 802, 804, and 806 has a head portion 830 having a relatively larger diameter than the guide protrusions in addition to the body portion 832 contacting the guide hole. The head portion 830 may play a role in maintaining the sliding member 304 in contact with the cover.

A plurality of pressing members 850 and 852 may be provided to keep the sliding member 304 placed on the cover in contact with the cover. The pressing members 850 and 852 are made of an elastic metal, and press the sliding members at a predetermined pressure to keep the sliding members in contact with the cover.

The pressing members 850 and 852 press the sliding member 304 with an appropriate pressure so as not to be greatly affected by the sliding operation of the sliding member 304. The urging members 850 and 852 of the elastic body are coupled to the urging member supporters 860 and 862 to apply pressure to the sliding member 304 at a predetermined height. The pressing member supporters 860 and 862 are in the form of protruding structures and the pressing member is coupled to the pressing member supporters 860 and 862 by means of bolting or the like.

9 is a cross-sectional view of a coupling structure of a sliding member and a motor according to an embodiment of the present invention.

Referring to FIG. 9, according to one embodiment of the present invention, a motor 316 is used in which the rotating shaft 900 slides in correspondence with the rotation of the motor. The sliding direction and the sliding range of the rotating shaft 900 is changed according to the rotation direction and the degree of rotation of the motor, the vertical member 902 is coupled to the rotating shaft 900, the vertical member 902 is coupled to the sliding member 304 do. The sliding motion of the rotating shaft 900 is transmitted to the sliding member 304 through the vertical member 902 to perform the sliding operation of the sliding member.

9 is only an embodiment of the present invention, it will be apparent to those skilled in the art that various types of sliding structures, such as a structure using a motor and a worm gear, as well as the structure of FIG. 9 can be used.

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

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

3 is an exploded perspective view of a tunable filter having a stable sliding structure according to an embodiment of the present invention.

FIG. 4 shows a cross-sectional view of one cavity in the filter shown in FIG. 3. FIG.

5 is a perspective view of a sliding member used in the tunable filter having a stable sliding structure according to an embodiment of the present invention.

6 is a 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 perspective view of a state in which a cover is coupled in a tunable filter having a stable sliding structure according to an embodiment of the present invention;

9 is a cross-sectional view of a coupling structure of a sliding member and a motor according to an embodiment of the present invention.

Claims (13)

A housing in which a plurality of cavities are defined by partitions; A resonator accommodated in the cavity; A cover coupled to the upper portion of the housing; And A sliding member slidably placed in the first direction on the cover and to which a plurality of tuning elements are coupled; The tuning element is inserted into the filter through a hole formed in the cover and positioned on the resonator, at least one guide hole is formed in the sliding member, and the cover includes at least one guide protrusion protruding through the guide hole. And a side surface portion of the guide protrusion is in contact with an inner surface of the guide hole facing in a second direction perpendicular to the first direction. The method of claim 1, The tunable filter having a stable sliding structure, wherein the guide hole has a predetermined length in the first direction in consideration of a sliding range of the sliding member. The method of claim 1, And at least one pressing member for pressing the sliding member to a predetermined pressure. The method of claim 3, The pressing member is a tunable filter having a stable sliding structure, characterized in that the metal body of elastic material. The method of claim 4, wherein The pressing member is coupled to the pressing member supporting portion protruding from the cover tunable filter having a stable sliding structure, characterized in that for pressing the sliding member. The method of claim 1, And a motor provided in the motor accommodating part and the motor accommodating part, wherein the sliding member receives a driving force from the motor. A housing in which a plurality of cavities are defined by partitions; A resonator accommodated in the cavity; A cover coupled to the upper portion of the housing; And A sliding member disposed movably on the cover, to which a plurality of tuning elements are coupled; The tuning element is inserted into the filter through a hole formed in the cover and positioned on the resonator, at least one guide hole is formed in the sliding member, and the cover includes at least one guide protrusion protruding through the guide hole. And a slidable filter having a stable sliding structure, the sliding movement of which is guided in a first predetermined direction by contact between the guide protrusion and the guide hole. The method of claim 7, wherein And a hole formed in the cover has a predetermined length in the first direction to allow the tuning element to slide. The method of claim 7, wherein The tunable filter having a stable sliding structure, wherein the guide hole has a predetermined length in the first direction in consideration of a sliding range of the sliding member. 10. The method of claim 9, The guide protrusion has a cylindrical shape, and the diameter of the cross section of the guide protrusion corresponds to the distance between the inner surface of the guide hole facing in the second direction perpendicular to the first direction, the tunable filter having a stable sliding structure. . The method of claim 7, wherein And at least one pressing member for pressing the sliding member to a predetermined pressure. The method of claim 11, The pressing member is a tunable filter having a stable sliding structure, characterized in that the metal body of elastic material. The method of claim 12, The pressing member is coupled to the pressing member supporting portion protruding from the cover tunable filter having a stable sliding structure, characterized in that for pressing the sliding member.

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