KR20140020616A - Resonator and cavity filter and transmission line for use therewith - Google Patents

Abstract

The present invention relates to a resonating bar for a communication device in which a plurality of grooves having a predetermined depth and width in the vertical direction on the outer surface of the resonating bar. A resonator using the metal resonating bar and a cavity filter employing the same according to the present invention can achieve a high performance even with a light weight and a small size. For example, a Q value can be increased by 180-200% while maintaining the same size as a convention.

Description

Resonator rod and cavity filter and transmission line employing it {RESONATOR AND CAVITY FILTER AND TRANSMISSION LINE FOR USE THEREWITH}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio frequency (RF) filter used in a wireless communication system. More particularly, the present invention relates to an RF filter (cavity filter) having a cavity structure, a resonant rod that can be employed in a cavity filter, and the like.

An RF filter with a cavity structure forms a cavity, such as a metallic cylinder or a cuboid, surrounded by a conductor, and has a resonator composed of a dielectric resonator (DR) or a metallic resonator rod, so that only a natural frequency electromagnetic field exists. As a result, it has a structure that enables resonance of ultra-high frequency. Since the RF filter having such a cavity structure has a low insertion loss and is advantageous for high output, it is applied to almost all the transmitting and receiving communication equipments such as a mobile communication base station, a repeater, a broadcasting repeater, and a satellite communication system, and a duplexer, a bandpass ) Filters, and various forms and structures have been developed depending on the required filtering characteristics.

The cavity filter is disclosed in Korean Patent Application No. 2002-84938 (name: radio frequency filter having a dielectric with a high dielectric constant and a high selectivity value, applicant: K.M. W. Co., Ltd., inventor: Jong- : December 27, 2002) and Patent Application No. 2002-52351 (name: radio frequency filter having a spring nut, applicant: K. W. Co., Ltd., inventor: Jong Kyu Park et al., Filed on August 31, 2002) For example.

Referring to FIG. 1A, the cavity filter is generally provided with a DR or metallic resonator rod 14 in a cavity 13 formed by a cover 12 and a housing 11 made of a metal material such as aluminum. At this time, the tuning adjustment screw 15 is installed in the corresponding position of the upper portion of the resonator rod 14 is fastened to the screw hole of the cover 12. FIG. 1B shows the side (a) and the plane (b) of the structure related to the internal resonator rod 14 of FIG. 1A. For the convenience of illustration, only the resonator rod 14 and the cavity 13 are shown. The illustration is omitted for. In addition, in FIG. 1A, a filter structure having one cavity 13 is illustrated for convenience of description, but a cavity filter may have a multi-stage structure in which a plurality of cavities are connected. In this case, each of the cavities may be divided into a plurality of diaphragms (not shown) where coupling windows are formed, and a cover adjusting screw (not shown) is provided on the cover 2 at a position corresponding to each coupling window .

Such a cavity filter may be classified into a TEM (Transverse Electro Magnetic) mode using a metallic resonator rod, a TE (Transverse Electric) using a DR resonator rod, a TM (Transverse Magnetic) mode, and the like, according to the resonator structure. Among them, the resonator (TE or TM resonator) using the DR resonator rod has a much higher Q (Quality factor) characteristic than the resonator using the metallic resonator rod (TEM resonator), but the manufacturing cost is several times higher and a relatively large volume. This was a disadvantage because it is difficult to apply to small products.

Accordingly, in recent years, the demand for resonators using metallic resonator rods is increasing to meet the demand for light weight and miniaturization of communication products in which the cavity filters are installed. Remains. Moreover, the commonly used cavity filter is proportional in size and performance, so if the size is reduced, the Q characteristic is worsened at the same time, which limits the size.

Accordingly, an object of the present invention is to provide a resonator rod and a cavity filter employing the same so as to satisfy light weight, small size, and high performance in a resonator using a metallic resonator rod.

Another object of the present invention is to provide a cavity filter and a resonant rod thereof that can significantly improve the Q characteristic while maintaining the same size as before.

Another object of the present invention is to provide a TEM mode transmission line (especially a coaxial line) for reducing transmission loss on a conductor by using the same principle as that of the resonator.

The present invention to achieve the above object

In the resonator rod for a communication device, the outer surface of the resonator hole is characterized in that a plurality of grooves having a predetermined width and depth in the longitudinal direction.

Preferably, the plurality of grooves are formed at equal intervals or at equal intervals.

Preferably, the plurality of grooves are each equal in width to each other.

Preferably, the plurality of grooves are composed of a plurality of types of grooves having depth differences from each other.

As described above, the resonator using the metallic resonant rod and the cavity filter employing the same according to the present invention can satisfy the high performance even though it is light and small, and, for example, maintains the same size as the conventional Q value of 180 to 200. Up to% can be improved.

In addition, according to the present invention, the transmission line using the same principle as the structure of the resonator can reduce the transmission loss on the conductor.

1A is an exploded perspective view of a part of a typical cavity filter
FIG. 1B is a side and top view of the internal resonator rod related structure of FIG. 1A
Figure 2a is a partially exploded perspective view of the cavity filter according to the first embodiment of the present invention
FIG. 2B is a side and top view of the internal resonance rod related structure of FIG. 2A
3 to 6 are side and plan views of a structure related to internal resonance rods of the cavity filters according to the second to fifth embodiments of the present invention.
7 is a side and a plan view of a structure related to internal resonance rods of a cavity filter according to a modification of the present invention;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be appreciated that those skilled in the art will readily observe that certain changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims. To those of ordinary skill in the art.

Figure 2a is a partially exploded perspective view of the cavity filter according to a first embodiment of the present invention, Figure 2b is a side (a) and a planar view (b) of the internal resonator rod related structure of Figure 2a, for convenience of illustration In FIG. 2B, only the resonance rod 24 and the cavity 23 are illustrated, and the rest of the structure is omitted. 2A and 2B, the cavity filter according to the first exemplary embodiment of the present invention has a cavity 23 formed by a cover 12 and a housing 11, which are usually made of a metal material such as aluminum, as in the related art. And, the cavity 23 is provided with a resonant rod 24 formed of a metallic cylindrical or cylindrical form. At this time, the tuning adjustment screw 15 is installed in the corresponding position of the upper portion of the resonator rod 24 is fastened to the screw hole of the cover 12.

In FIG. 2A and FIG. 2B, a filter structure having one cavity 23 is illustrated for convenience of description, but a cavity filter may have a multi-stage structure in which a plurality of cavities are connected. In this case, each cavity may be divided into a plurality of diaphragms (not shown) in which the coupling windows are formed, and the coupling adjusting screws (not shown) may be provided in the cover 12 at positions corresponding to the respective coupling windows. Can be.

In this structure, the outer surface of the resonator rod 24 is provided with a plurality of grooves 26 (eight in the example of FIGS. 2A and 2B) with a predetermined width and depth long in the longitudinal direction in accordance with the features of the present invention. As shown in FIG. 2B, the eight grooves 26 are formed at equal intervals from each other. The width of the plurality of grooves 26 is relatively narrow so that the high frequency signal of the cavity filter may be transmitted in a non-contact coupling manner in the air gap formed by the groove 26.

The structure according to the first embodiment of the present invention as shown in FIGS. 2A and 2B has a high Q value even when the structure has the same size as compared with the conventional structures shown in FIGS. 1A and 1B. In certain design conditions, for example, when the size (diameter x height) of the resonator rods 13 and 24 is 50x55 mm, the Q value can be improved by about 110%.

As described above, the resonator rod 24 in which the groove 26 is formed in accordance with the characteristics of the present invention may have superior Q characteristics as compared with the conventional art, on the surface of the resonator rod through which the signal is transmitted. This is due to the signal being transmitted in a non-contact coupling manner which is substantially free of conduction losses on the conductor.

Figure 3 shows the side (a) and planar (b) structure of the internal resonance rod-related structure of the cavity filter according to the second embodiment of the present invention. The structure according to the second embodiment of the present invention shown in FIG. 3 is compared with the first embodiment shown in FIGS. 2A and 2B, and 24 grooves (not shown) are formed in the resonance rod 34 provided in the cavity 33. The only difference is that 36) is formed. The structure according to the second embodiment can be improved by about 119% Q compared with the conventional structures shown in FIGS. 1A and 1B.

4 shows the side (a) and planar (b) structures of the internal resonant rod-related structure of the cavity filter according to the third embodiment of the present invention. The structure according to the third embodiment of the present invention shown in FIG. 4 is different only in that 72 grooves 36 are formed in the resonance rod 44 provided in the cavity 43. The structure according to the third embodiment can be improved by about 150% Q compared with the conventional structures shown in FIGS. 1A and 1B.

FIG. 5 shows the side (a) and planar (b) structures of the internal resonance bar related structure of the cavity filter according to the fourth embodiment of the present invention. In the structure according to the fourth embodiment of the present invention illustrated in FIG. 5, 144 grooves 56 are formed in the resonator rod 54 provided in the cavity 53. The structure according to the fourth embodiment can be improved by about 180% compared to the conventional structure.

6 shows the side (a) and planar (b) structures of the internal resonance bar related structure of the cavity filter according to the fifth embodiment of the present invention. In the structure according to the fifth embodiment of the present invention illustrated in FIG. 6, two kinds of grooves 66-1 and 66-2 having different depths from each other are formed in the resonance rod 64 provided in the cavity 63. It has a structure of 16 pieces each. That is, the groove 66-1 having the first depth and the groove 66-2 having the second depth having a different depth are alternately formed. The structure according to the fifth embodiment can be improved by about 120% Q compared with the conventional structure.

Looking at the plurality of embodiments of the present invention, it can be seen that the Q value of the resonator is improved according to the number and shape of the grooves formed in the resonator rod.

In addition, the more densely formed grooves are formed in the resonator rod, the resonator rod becomes similar to a shape in which a thin plate (corresponding to the remaining portion in which the groove is not formed) is radially attached to the side surface as if it is formed vertically long. The narrower and thinner the plate structure is, the better the width of the groove and the thickness of the plate structure are designed.

As described above, a resonator rod and a cavity filter employing the same may be configured, and in the above description of the present invention, a specific embodiment has been described, but various modifications do not depart from the scope of the present invention. It can be done without. For example, the number and shape of the grooves formed in the resonance rod may be variously designed in addition to those mentioned in the above embodiments.

In addition, in the above embodiments, the plurality of grooves have been described as being formed long from the top to the bottom over the entire height of the resonator rod. In addition, the plurality of grooves may be formed only in the upper portion of the resonator rod.

In addition, in the above embodiments, a plurality of grooves have been described as having a uniform interval as a whole on the outer surface of the resonator rod, the interval between the plurality of grooves may be formed irregularly, or a plurality of grooves are partially in the resonator rod It may also be formed only at sites, for example half sites, or 3/4, 1/3 sites. In FIG. 7, an example in which the plurality of grooves are formed only at a third portion of the resonance rod is shown. In addition, the resonator rod has been described as having a cylindrical or cylindrical shape, but in addition, the resonator rod may have a square pillar shape or at least a portion of the irregular shape.

In addition, the structure of the resonator described above is a resonator using a TEM mode, which can be regarded as a kind of TEM mode coaxial line structure, and can be applied to a transmission line with the same structure. In this case, the resonator rod serves as an inner center conductor, and a plurality of grooves having a predetermined width and depth are formed on the outer surface of the inner center conductor in the longitudinal direction of the inner center conductor. Outside the inner center conductor, an insulator, an outer conductor, an outer sheath, and the like can be formed, similarly to the structure of a conventional coaxial line.

Claims (7)

In the resonance rod for a communication device,
Resonator rod, characterized in that formed on the outer surface of the resonant hole a plurality of grooves of a predetermined width and depth in the longitudinal direction.
The method of claim 1,
The plurality of grooves are resonance bars, characterized in that formed at equal intervals or boiling intervals.
3. The method of claim 2,
Resonance rods, characterized in that the plurality of grooves each width is equal to the interval between each other.
The method of claim 1,
The plurality of grooves,
Resonator rod, characterized in that composed of a plurality of grooves having a depth difference from each other.
The method of claim 1,
The plurality of grooves,
Resonator rods, characterized in that formed on a portion of the outer surface of the resonator rods.
The cavity filter which employ | adopted the resonance rod in any one of Claims 1-5.
In the transmission line,
An insulator and an outer sheath are formed outside the inner center conductor and the inner center conductor,
Transmission lines, characterized in that the outer surface of the inner center conductor is formed with a plurality of grooves of a predetermined width and depth in the longitudinal direction of the inner center conductor.

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