KR20110068142A - Tunable filter enabling adjustment of tuning characteristic and tuning range - Google Patents

Abstract

PURPOSE: A tunable filter is provided to be adaptively used in various environments by enabling a user to control a tuning property and a tuning range. CONSTITUTION: A resonator(310) is received at a cavity(308). A sliding member(312a,312b) is installed on the upper side of the resonator. A control bolt is combined with the sliding member through a bolt hole. A thread is formed on the side of the control bolt. A tuning element(330) is combined with the lower side of the control bolt and is located on the upper side of the resonator. The bolt hole has a thread. A distance between the tuning element and the resonator is controlled by the rotation of the control bolt.

Description

Tunable Filter Enabling Adjustment of Tuning Characteristic and Tuning Range

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 used to vary 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 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 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 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.

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.

The tunable filter using the sliding method has an advantage in that the user can tune by merely moving the sliding member from side to side without having to rotate the bolt.

However, such a sliding type tunable filter has a problem in that the tuning range and the tuning degree according to the sliding are fixed, and thus cannot be adaptively used in various environments.

In order to solve the problems of the prior art as described above, the present invention is to propose a tunable filter that can be adjusted by the user without the tuning characteristics and tuning bandwidth fixed.

Another object of the present invention is to propose a tunable filter which can be adaptively used in various environments.

According to a preferred embodiment of the present invention to achieve the above object, at least one cavity therein is defined by the partition walls; At least one resonator received in the cavity; At least one sliding member installed above the resonator; At least one adjustment bolt coupled to the sliding member through a bolt hole coupled to the sliding member and having a thread formed on a side thereof; And at least one tuning element coupled to a lower portion of the adjusting bolt and positioned above the resonator, wherein a thread is formed in the bolt hole to adjust a distance between the tuning element and the resonator by rotation of the adjusting bolt. A tunable filter is provided.

The tunable filter may further include a sub cover coupled to an upper portion of the housing and on which the sliding member is placed.

The sub cover is formed with a hole through which the adjustment bolt passes.

A guide groove for guiding the sliding operation of the sliding member is formed in the sub cover.

The insertion depth of the adjustment bolt can be fixed by the nut.

When a plurality of resonators and a plurality of tuning elements are provided, the distances between each resonator and the tuning elements may be set differently in part.

According to another aspect of the invention, the housing is a plurality of cavities defined therein by the partition walls; At least one resonator received in the cavity; At least one sliding member installed above the resonator; At least one height adjustment member coupled to a lower portion of the sliding member; And a tuning element coupled to a lower end of the height adjusting member and positioned above the resonator, wherein a distance between the tuning element and the resonator is adjusted by the height adjusting member.

The present invention has the advantage that the tuning characteristics and tuning bandwidth can be adjusted by the user without being fixed and can be adaptively used in various environments.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate a thorough understanding of the present invention, the same reference numerals are used for the same means regardless of the number of the drawings.

3 is an exploded perspective view of a tunable filter capable of adjusting tuning characteristics and tuning range according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the slidable tunable filter to which the present invention is applied includes a housing 300, an input connector 302, an output connector 304, a main cover 306, a plurality of cavities 308, and a plurality of tunable filters. The resonator 310 may include a sliding member 312a and 312b, a sub cover 314, and a driver 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.

A plurality of partitions are formed inside the tunable filter, and the partitions define a cavity 308 in which the resonator 310 is accommodated together with the housing 300.

The number of cavities 308 and resonators 310 is associated with the order of the filter, and FIG. 3 shows an order of eight, i.e., eight resonators. The order of the filter is associated with skirt characteristics and insertion loss. At this time, the skirt characteristic and insertion loss have a trade off relationship. In other words, the higher the filter order, the higher the skirt characteristics, but the worse the insertion loss. Thus, the order of the filter (i.e. the number of cavities 308 and resonator 310) is determined by the skirt characteristics and the insertion loss required.

Some of the partition walls have coupling windows corresponding to the traveling directions of the RF signals (or frequency signals). The RF signal resonated by the cavity 308 and the resonator 310 proceeds to the next cavity through the coupling window.

The main cover 306 and the sub cover 314 may be coupled to the housing 300 at the upper portion of the housing 300, and may be coupled to the housing 300 by bolt coupling through a plurality of fastening holes. A guide groove 320 is formed in the sub cover 314 so that the sliding members 312a and 312b can be slidably.

The sliding members 312a and 312b are installed to be slidable in a direction perpendicular to the direction in which the resonator 310 stands, that is, in a horizontal direction. In this case, the sliding members 312a and 312b are positioned in the guide groove 320 formed on the sub cover 314.

The number of sliding members 312a and 312b may correspond to the number of resonator lines formed in the filter. 3 shows a filter having two resonator lines in which four resonators are distributed in each line, and the number of sliding members 312a and 312b is correspondingly two.

It will be apparent to those skilled in the art that the sliding member 3, which is illustrated in FIG. 3, in which two sliding members 312a and 312b exist independently, may be implemented in an integrated structure.

The tuning element 330 is coupled to the lower portion of the sliding members 312a and 312b. The tuning element 330 is coupled with the sliding members 312a and 312b through the adjustment bolt 700, and the adjustment bolt 700 penetrates into the filter through the hole 322 formed in the sub cover 314. The tuning element 330 may be formed of a metal material or a dielectric material. Meanwhile, the material of the sliding members 312a and 312b is preferably a dielectric material.

The tuning element 330 is coupled to the lower portion of the sliding members 312a and 312b in correspondence with the resonator 310, and a corresponding tuning element is provided for each resonator. There are four resonators under each of the sliding members 312a and 312b, and thus four tuning elements are coupled to each of the sliding members 312a and 312b. In addition, the distance of the tuning elements to be coupled corresponds to the installation distance of the resonator 310.

The position of the coupled tuning element 330 is also variable corresponding to the sliding of the sliding members 312a and 312b. The tuning element 330 forms capacitance by interaction with the resonator 310, and when the position of the tuning element 330 is changed, the capacitance is changed.

The capacitance is determined by the distance and the cross-sectional area between the two metal bodies. As the position of the tuning element of the metal is changed, the cross-sectional area between the resonator and the tuning element is changed. Accordingly, the capacitance can be varied and the filter can be tuned. .

Although not shown in FIG. 3, a tuning bolt for tuning at the time of manufacture of a filter may be inserted into the filter from the sub cover 314, and the role of the inserted tuning bolt is the same as that of a conventional filter.

4 and 5 illustrate a coupling relationship between the sliding members 312a and 312b and the driving unit 316 according to an embodiment of the present invention.

The motor 500 provides a rotational force, and the rotational force of the motor 500 is provided to the gear unit 502.

The gear unit 502 converts the rotational motion of the motor 500 into the horizontal motion, and the intermediate member 504 is coupled to the gear part 502 and the sliding members 312a and 312b so that the horizontal movement force is applied to the sliding member 312a, 312b) to slide the sliding members 312a and 312b.

At this time, the intermediate member 504 is formed with a screw hole (not shown) for coupling the gear portion 502 and a coupling hole 510 for coupling with the sliding members 312a and 312b. A screw thread is formed in the coupling hole 510 so that the intermediate member 504 and the sliding members 312a and 312b may be coupled to each other by screwing. Of course, the coupling method is not limited to screw coupling, and various coupling methods may be used. In addition, one end of the sliding member (312a, 312b) is coupled to the intermediate member 504, the other end is not fixed. This is for free sliding.

In FIGS. 3, 4, and 5, the gear unit 502 converts the rotational motion of the motor into the horizontal motion and is transmitted to the sliding members 312a and 312b. However, this is only an example, and the motor 500 may be used. Various driving mechanisms known in the art may be used if it is possible to convert the rotational motion of to horizontal motion.

FIG. 6 is a diagram illustrating a concept in which a frequency characteristic is tuned according to sliding of a tuning element in a tunable filter according to an embodiment of the present invention.

Referring to FIG. 6, as the sliding members 312a and 312b slide, the tuning element 330 coupled thereto also slides. As the tuning element 330 moves, the range where the upper portion of the resonator 310 and the tuning element 330 overlap is changed, and thus the capacitance value whose cross-sectional area is a parameter is changed.

In FIGS. 4 and 5, the resonator 310 has a disk shape, and the tuning element 330 has a disk shape. However, in one embodiment, the resonator 310 and the tuning element 330 have various shapes. Can be implemented.

In the tunable filter of the present invention operating as described above, the tuning element 330 is installed in a structure capable of adjusting the distance to the resonator. In the conventional tunable filter, the position of the tuning element is fixed, and the tuning characteristics and tuning according to sliding The range is also fixed: the user may require larger or smaller tuning extents as needed and may require larger or smaller tuning ranges. It could not meet the needs of such users.

In the present invention, the tunable filter adopts a structure that can adjust the distance between the tuning element and the resonator so that the user can change the tuning characteristics and tuning range. Hereinafter, a structure in which the tuning element and the resonator distance can be adjusted will be described with reference to FIGS. 7 and 8.

7 is a diagram illustrating a perspective view of a sliding member in a tunable filter according to an embodiment of the present invention, and FIG. 8 is a cross-sectional view of the sliding member in a tunable filter according to an embodiment of the present invention.

7 and 8, the tuning element 330 is coupled with the sliding member 312 via an adjustment bolt 700 threaded to its side. The adjusting bolt 700 passes through the bolt hole 702 formed in the sliding member, and the bolt hole 702 is formed with a thread.

The tuning element 330 is coupled to the bottom of the adjustment bolt 700 through the sliding member.

Since the adjustment bolt 700 is coupled to the sliding member through the threaded bolt hole 702, it is possible to adjust the insertion depth into the lower portion of the sliding member by rotation. When the insertion depth of the adjustment bolt 700 under the sliding member is adjusted by rotation, the adjustment bolt 700 is fixed by the nut 710.

According to the present invention, the distance from the resonator of the tuning element 300 coupled to the adjusting bolt 700 is varied by varying the insertion depth of the adjusting bolt 700 by the rotation of the adjusting bolt 700.

7 and 8, by adjusting the adjustment bolt 700, the first tuning element 330a and the fourth tuning element 330d are connected to the second tuning element 330b and the third tuning element 330c. The case is shown relatively above.

9 is a view showing a state in which the position of the tuning element is changed by the position adjustment structure of the tuning element of the present invention.

In Fig. 9, (a) is an initial state, and (b) shows a state where the position of the tuning element is changed by the adjustment bolt. As shown in FIG. 9, it is possible to insert the adjustment bolt deeper below the tuning element by the rotation of the adjustment bolt so that the distance between the resonator and the tuning element is closer.

As such, the tuning characteristic and the tuning range can be adjusted by the structure capable of adjusting the distance between the tuning element and the resonator. Capacitance is a function of area, but is also a function of permittivity and distance, so that when the distance between the tuning element and the resonator varies, the capacitance can be changed and the tuning characteristics and tuning range according to the sliding can be adjusted.

7 and 8, a plurality of first guide members 800 may be coupled to one side of the sliding member 312, and a plurality of second guide members 810 may be disposed on the upper side of the sliding member 312. ) May be combined. The first guide member 800 and the second guide member 810 are combined to limit unnecessary movement of the sliding member 312.

That is, the sliding member 312 should be slid only in the length (vertical) direction, and the vertical movement or the horizontal movement should be removed when sliding. To this end, the first guide member 800 and the second guide member 810 remove unnecessary movement in the vertical direction or the horizontal direction, and allow the sliding member to slide only in a predetermined direction.

That is, the first guide member 800 and the second guide member 810 function to guide sliding so that the sliding member 312 slidably slides in the guide groove formed on the sub cover. In this case, the first guide member 800 and the second guide member 810 are made of an elastic material, and preferably may be implemented as a leaf spring.

Although FIG. 4 illustrates that the first guide member 800 is coupled to only one side, the first guide member 800 may be coupled to both sides of the sliding member.

In addition, although the sliding member is described as sliding on the guide groove formed in the sub cover in FIG. 4, the sliding member may be directly installed between the main cover and the resonator to slide. In this case, the sub cover, the first guide member, and the second guide member may not be provided.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art to which the present invention pertains, various modifications and variations are possible. Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

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 capable of adjusting tuning characteristics and tuning range according to an exemplary embodiment of the present invention.

4 and 5 illustrate a coupling relationship between the sliding members 312a and 312b and the driving unit 316 according to an embodiment of the present invention.

6 is a view illustrating a concept in which a frequency characteristic is tuned according to sliding of a tuning element in a tunable filter according to an embodiment of the present invention.

7 is a perspective view of a sliding member in a tunable filter according to an embodiment of the present invention.

8 is a cross-sectional view of a sliding member in a tunable filter according to an embodiment of the present invention.

9 is a view showing a state in which the position of the tuning element is changed by the position adjustment structure of the tuning element of the present invention.

Claims (7)

A housing in which at least one cavity is defined by the partitions; At least one resonator received in the cavity; At least one sliding member installed above the resonator; At least one adjustment bolt coupled to the sliding member through a bolt hole coupled to the sliding member and having a thread formed on a side thereof; And At least one tuning element coupled to a lower portion of the adjustment bolt and positioned above the resonator, The bolt hole is formed with a screw thread is tunable filter, characterized in that the distance between the tuning element and the resonator is adjusted by the rotation of the adjustment bolt. The method of claim 1, A tunable filter coupled to the housing and further comprising a sub cover on which the sliding member is placed. The method of claim 2, The sub-cover is a tunable filter, characterized in that the hole for the adjustment bolt is formed. The method of claim 3, wherein The sub-cover is provided with a guide groove for guiding the sliding operation of the sliding member. The method of claim 1, The insertion depth of the adjustment bolt is tunable filter, characterized in that fixed by a nut. The method of claim 1, Tunable filter, characterized in that the distance between each resonator and the tuning element is set partially different when a plurality of resonators and a plurality of tuning elements are provided. A housing in which a plurality of cavities are defined therein by partitions; At least one resonator received in the cavity; At least one sliding member installed above the resonator; At least one height adjustment member coupled to a lower portion of the sliding member; A tuning element coupled to a lower end of the height adjustment member and positioned above the resonator, And the distance between the tuning element and the resonator is adjusted by the height adjustment member.

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