KR101115323B1 - Band rejection filter and band rejection filter circuit by the same - Google Patents

Abstract

PURPOSE: A band rejection filter and a band rejection filter circuit by the same are provided to implement easy minute control of coupling by controlling the coupling between a transmission line and a resonator. CONSTITUTION: A housing(110) has a barrier rip(150) with a plurality of hollows(140). A housing cover(120) covers open one side of the housing. A resonator(160) is installed in the one side of hollow. A transmits line(130) maintains the interval from the resonator. A tuning bolt(170) changes the coupling between resonator and the transmits line.

Description

Band Rejection Filter and Band Rejection Filter Circuit By It {Band Rejection Filter And Band Rejection Filter Circuit By The Same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a band rejection filter (BRF). More particularly, the present invention relates to a band reject filter that easily adjusts capacitance and frequency characteristics formed between a resonator and a transmission line, and a band reject filter circuit. .

A typical high frequency filter forms a plurality of cavities in a metal housing surrounded by a conductor, and includes a dielectric resonator or a metal resonator inside each cavity to form an electromagnetic field of a specific frequency, thereby enabling ultra high frequency resonance. It has a structure

The high frequency filter using such a resonator is largely classified into a band pass filter (BPF) and a band stop filter according to the filtering characteristics of the frequency band. The band stop filter is classified into a band stop filter (BSF).

A band reject filter is a filter that blocks a specific frequency band among many frequencies and passes the remaining frequency band. Such band rejection filters are currently researched and developed in an effort to improve and control the filtering characteristics thereof, and various technologies have been disclosed.

For example, the band reject filter disclosed in Korean Patent Publication No. 10-0992089 (Notice date: November 05, 2010) is for electrically coupling the signal input terminal and the signal output terminal for coupling with the resonator in the housing. The transmission line is installed to be located above the resonator. Therefore, the band reject filter effectively suppresses the generation of various parasitic resonance modes, has a wide pass band, can be implemented in a smaller size, and can easily tune the filtering characteristics.

However, such band-stop filters generally have to adjust the bandwidth, that is, the distance between the resonator and the housing, the distance between the resonator and the housing cover, and / or the distance between the resonator and the transmission line, in order to adjust the capacitance, the capacitance and the frequency. Therefore, the conventional band reject filter has to rework the component in response to such a characteristic change, which makes it difficult to increase the manufacturing cost and tune the coupling.

It is an object of the present invention to provide a band reject filter and thereby a band reject filter circuit, in which the amount of coupling between a transmission line and a resonator is easily adjusted.

It is another object of the present invention to provide a band reject filter and a band reject filter circuit for arranging transmission lines on the resonator side.

It is still another object of the present invention to provide a band reject filter and thereby a band reject filter circuit which is easy to tune in frequency and can reduce manufacturing costs.

To achieve the above objects, the band reject filter of the present invention is characterized by arranging the transmission line on the side of the resonator. Such a band stop filter is easy to fine-tune the amount of coupling formed by the transmission line and the resonator in response to the frequency characteristic change by adjusting the distance between the resonator and the housing cover by the tuning bolt.

According to an aspect of the present invention, a bandstop filter includes: a housing having one surface open, an input port and an output port provided at both sides thereof, and a plurality of partition walls provided therein to form a plurality of cavities at regular intervals; A housing cover covering the open one side of the housing; A resonator installed at one side of each of the cavities; A transmission line connecting between the input port and the output port inside the housing and disposed on side surfaces of the resonators to maintain a constant distance from the resonator; A plurality of tuning bolts installed on the housing cover to be disposed above each of the resonators, and varying an amount of coupling between the resonator and the transmission line by adjusting a distance between the housing cover and the resonator. .

In one embodiment, the partition wall; A portion disposed between the cavities and the portion where the resonator is installed is cut off, and a portion where the transmission line is installed is formed with a window open.

In another embodiment, the transmission line; A coaxial line installed in the window to electrically connect the input port and the output port to the inside of the housing; A plurality of capacitive conductors are provided on the coaxial line so as to be disposed at positions opposite to each of the resonators, and an outer circumferential surface thereof is spaced apart from the side surface of the resonator by a predetermined distance.

In this embodiment, the capacitive conductor comprises; It extends from the central axis of the coaxial line is provided in a shape having a larger diameter than the coaxial line.

According to another feature of the invention, there is provided a band stop filter circuit comprising a variable capacitor formed by a resonator and a transmission line. The band stop filter circuit of the present invention can finely adjust the capacitance between the resonator and the housing cover by the tuning bolt, thereby finely adjusting the capacitance of the variable capacitor.

The band rejection filter circuit of the present invention according to this aspect comprises a plurality of LC parallel resonant circuits formed by a transmission line disposed on the side of the plurality of resonators and electrically connecting the input port and the output port, and connected in series with each other; ; A plurality of LC series resonant circuits each formed between the LC parallel resonant circuits adjacent by each of the resonators; And a variable capacitor formed by the resonator and the transmission line disposed at one side of the transmission line, and variable in capacitance between the transmission line and the resonator by a plurality of tuning bolts corresponding to each of the resonators.

In one embodiment, the variable capacitor; The capacitance is roughly adjusted by at least one of the spacing between the housing and the resonator, and the dielectric constant, cross-sectional area and spacing between the transmission line and the resonator, and by the tuning bolt at the spacing between the resonator and the housing cover. Finely controlled by

As described above, in the band reject filter of the present invention, fine adjustment of the coupling amount is easy by arranging the transmission line on the side of the resonator and adjusting the coupling amount between the transmission line and the resonator by means of tuning bolts.

Therefore, the band reject filter of the present invention does not need to rework components according to the change in frequency characteristics, thereby reducing manufacturing costs.

1 is an exploded perspective view showing the configuration of a band reject filter according to the present invention;
FIG. 2 is a plan view showing the configuration of the band reject filter shown in FIG. 1; FIG.
FIG. 3 is a side view showing the configuration of the band reject filter shown in FIG. 1; FIG.
4 is a circuit diagram showing the configuration of the band reject filter shown in FIG. 1; And
5 is a waveform diagram illustrating frequency characteristics of the band reject filter shown in FIG. 1.

The embodiments of the present invention can be modified into various forms and the scope of the present invention should not be interpreted as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and the like of the components in the drawings are exaggerated in order to emphasize a clearer explanation.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5.

1 is an exploded perspective view showing the configuration of a band reject filter according to the present invention, FIG. 2 is a plan view of the band reject filter shown in FIG. 1, and FIG. 3 is a side view of FIG. 1.

1 to 3, the band reject filter 100 of the present invention includes a housing 110, a housing cover 120, and a transmission line 130. In addition, the band reject filter 100 includes a plurality of cavities 150 formed in the housing 110 and a plurality of resonators 160 installed in each of the cavities 140. The housing cover 120 is provided with a plurality of tuning bolts 170. The transmission line 130 is installed at the side of the resonator 160 in the housing 110. In addition, the housing 110, the housing cover 120, the transmission line 130, and the resonator 160 may be formed of a metal material, for example, aluminum, copper, and iron.

The band rejection filter 100 of the present invention includes a gap between the resonator 160 and the housing 110 (d2 of FIG. 2), between the resonator 160 and the housing cover 120, in order to adjust capacitance and frequency characteristics. By adjusting the interval d3 and the interval d1 between the resonator 160 and the transmission line 130, the manufacturing cost according to the frequency characteristic change is reduced, and the coupling tuning is easy.

Specifically, the housing 110 is provided with a metal material having a rectangular parallelepiped shape in which one surface (for example, an upper surface) is open. The housing 110 is provided with an input port 112 and an output port 114 for transmitting signals on both sides. Specifically, each of the input port 112 and the output port 114 is mounted from the outside of the housing 10 to the inside. The input port 112 and the output port 114 are electrically connected by a transmission line 130 for signal transmission inside the housing 110.

The housing 110 is formed with a plurality of cavities 140 partitioned at regular intervals from the input port 112 toward the output port 114. The cavities 140 are partitioned by the partition wall 150, and each of the cavities 140 is provided with a rod-shaped resonator 160 vertically from the lower side of the housing 110 to the upper direction. In addition, the housing 110 is provided with a plurality of coupling grooves 116 on the upper surface. The coupling groove 116 may be further provided on the upper surface of the partition wall 150.

The resonator 160 may be made of a metal material, and a plurality of resonators 160 may be provided, for example, about 8 to 15 pieces. In the initial design, as shown in FIG. 2, the resonator 160 calculates a rough coupling value through simulation, and correspondingly, the distance d3 between the housing 110 and the resonator 160 is constant. It is fixed and installed.

In the partition wall 150, a window 152 is formed to partially open the adjacent cavity 140. That is, the partition wall 150 is disposed between the cavities 140 to block the portion where the resonator 160 is installed and the window 152 is formed to open the portion where the transmission line 130 is installed.

The housing cover 120 is provided with a plurality of tuning bolts 170 at positions corresponding to each of the resonators 160. Each tuning bolt 170 fine tunes the gap between the housing cover 120 and the resonator 160. In addition, the housing cover 120 has a plurality of coupling holes 122 formed at positions corresponding to each of the coupling grooves 116 formed on the upper surface of the housing 110. Therefore, the housing 110 and the housing cover 120 are coupled by the coupling groove 116 of the housing 110, the coupling hole 122 of the housing cover 120, and the coupling screw 124.

In addition, the transmission line 130 may be formed of, for example, a metal material and disposed on the side of the resonator 160 in the housing 110. To this end, the transmission line 130 is fixed and installed in the window 152 formed on the partition wall 150. In this case, as shown in FIG. 2, the transmission line 130 has an interval d1 between the transmission line 130 and the resonator 160 in response to the rough coupling value calculated through the simulation in the initial design. Is fixed to the window 152 to keep it constant. The window 152 here has a width W greater than the diameter D of the transmission line 130.

The transmission line 130 includes a coaxial line 132 electrically connecting the input port 112 and the output port 114, and a capacitive conductor 134 having an outer circumferential surface disposed on the side of the resonator 160. . Coaxial line 132 is connected at both ends to input port 112 and output port 114 to transmit a signal from input port 112 to output port 114. The capacitive conductor 134 is provided on the coaxial line 132 where the resonator 160 is disposed. The capacitive conductor 134 extends outward from the central axis of the coaxial line 132 and is provided in a cylindrical or cylindrical shape having a diameter larger than that of the coaxial line 132.

Coaxial line 132 is located on window 152 of partition 150, and capacitive conductor 134 is disposed at a position corresponding to the side of resonator 160. Therefore, the coaxial line 130 is moved left and right inside the window 152 of the partition wall 150 to adjust the coupling value according to the initial design. In the transmission line 130, the input port 112 and the output port 114 are fixed to both sides of the housing 110 such that the distance d1 between the capacitive conductor 134 and the resonator 160 is fixed.

As described above, the band reject filter 100 of the present invention adjusts by varying the amount of coupling between the transmission line 130 and the resonator 160 in order to adjust the desired bandwidth (band width). To this end, in the initial design, the band reject filter 100 schematically adjusts the distance d2 between the resonator 160 and the housing 110 and the distance d1 between the resonator 160 and the transmission line 130. By finely adjusting the distance d3 between the resonator 160 and the housing cover 110 by the tuning bolt 170, the capacitance formed between the transmission line 130 and the resonator 160 is variably adjusted.

4 is a circuit diagram showing the configuration of the band reject filter according to the present invention, and FIG. 5 is a waveform diagram showing the frequency characteristics of the band reject filter according to the present invention. Here, the circuit diagram is formed by the components of the band reject filter according to the embodiment shown in FIG. 1 and will be described in detail using these components. In this embodiment, a circuit configuration (hereinafter referred to as a 'band stop filter circuit') is described using a band stop filter including five resonators, but the circuit configuration can be changed and modified in various ways according to the number of resonators. .

Referring to FIG. 4, the band reject filter circuit 100 includes an input and an output having an impedance of, for example, 50 Ohms at both ends of the transmission line 130 connected between the input port 112 and the output port 114. Form terminations (Term1, Term2). The band stop filter circuit 100 includes a plurality of LC parallel resonant circuits 130a to 130e formed by the transmission line 130. The band reject filter circuit 100 also includes a plurality of LC series resonant circuits 160a to 160d formed by each of the plurality of resonators 160. In addition, the band suppression filter circuit 100 is formed by the transmission line 130 and the respective resonators 160, and the plurality of variable capacitors VC1 to VC4 whose capacitance is adjusted by fine adjustment of each tuning bolt 170. Include them.

In this embodiment, band reject filter circuit 100 includes first to fifth LC parallel resonant circuits 130a to 130e formed by transmission line 130 between input and output terminations Term1 and Term2. . One inductor L1 to L5 and one capacitor C1 to C5 are connected in parallel to each of the first to fifth LC resonant circuits 130a to 130e.

First to fourth LC series resonant circuits 160a to 160d are formed between adjacent LC parallel resonant circuits among the first to fifth LC parallel resonant circuits 130a to 130e, respectively. That is, a first LC series resonant circuit 160a is formed between the first and second LC parallel resonant circuits 130a and 130b, and a first LC second resonant circuit 130b and 130c is formed between the first and second LC parallel resonant circuits 130a and 130b. A two LC series resonant circuit 160b is formed, a third LC series resonant circuit 160c is formed between the third and fourth LC parallel resonant circuits 130c, 130d, and a fourth and fifth LC parallel A fourth LC series resonant circuit 160d is formed between the resonant circuits 130d and 130e. One inductor L6 to L9 and one capacitor C6 to C9 are connected in series to each of the first to fourth LC series resonant circuits 160a to 160d. The inductors L6 to L9 are connected to the variable capacitors VC1 to VC4, and the capacitors C6 to C9 are grounded.

Each of the first to fourth variable capacitors VC1 to VC4 is formed between the first to fifth LC parallel resonant circuits 130a to 130e and the first to fourth LC series resonant circuits 160a to 160d. do.

At this time, the capacitance of each of the first to fourth variable capacitors VC1 to VC4 is the dielectric constant between the transmission line 130 and the resonator 160, the cross-sectional area and the distance between the transmission line 130 and the resonator 160 ( The capacitance is finely adjusted by adjusting the distance d3 between the housing cover 120 and the resonator 160 by the tuning bolt 170.

In the band rejection filter circuit 100 of the present invention, as shown in FIG. 5, the S parameter representing the reflection coefficient S11 and the transmission coefficient S21 blocks a frequency band of about 0.9 to 1.0 GHz. To this end, the band stop filter 100 arranges the transmission line 130 on the side of the resonator 160 and uses the tuning bolt 170 to adjust the distance d2 between the resonator 160 and the housing cover 120. By fine adjustment, the capacitance formed by the transmission line 130 and the resonator 160 is adjusted.

Therefore, the bandwidth to be blocked by the band stop filter circuit 100 of the present invention is controlled by the tuning bolt 170 to adjust the amount of coupling between the transmission line 130 and the resonator 160, thereby finely adjusting the amount of coupling. This is easy, and there is no need to rework the components of the band reject filter 100 according to the frequency characteristic change.

In the above, the configuration and operation of the band stop filter according to the present invention is shown in accordance with the detailed description and drawings, which are merely described by way of example, and various changes and modifications may be made without departing from the spirit of the present invention. It is possible.

100: band stop filter 110: housing
112: input port 114: output port
120: housing cover 130: transmission line
132: coaxial line 134: capacitive conductor
140: cavity 150: bulkhead
152: window 160: resonator
170: tuning bolt

Claims (6)

For the band reject filter:
A housing having one side open, an input port and an output port provided at both sides thereof, and having a plurality of partition walls provided therein, the plurality of partitions forming a plurality of cavities at regular intervals;
A housing cover covering the open one side of the housing;
A resonator installed at one side of each of the cavities;
A transmission line connecting between the input port and the output port inside the housing and disposed on side surfaces of the resonators to maintain a constant distance from the resonator;
A plurality of tuning bolts installed on the housing cover to be disposed above each of the resonators, and varying an amount of coupling between the resonator and the transmission line by adjusting a distance between the housing cover and the resonator. Band reject filter, characterized in that. The method of claim 1,
The partition wall;
And a portion of the cavity disposed between the cavities is cut off, and a portion of the transmission line is formed with a window formed to open. The method of claim 2,
The transmission line;
A coaxial line installed in the window to electrically connect the input port and the output port to the inside of the housing;
And a plurality of capacitive conductors disposed on the coaxial line so as to be disposed at positions opposite to each of the resonators, and having an outer circumferential surface spaced apart from the side surface of the resonator by a predetermined distance. The method of claim 3, wherein
The capacitive conductor;
And a band stop filter extending from a central axis of the coaxial line and having a diameter larger than that of the coaxial line. In the band reject filter circuit formed by the band reject filter according to any one of claims 1 to 4,
A plurality of LC parallel resonant circuits, each of which is formed by the transmission line, one inductor and one capacitor connected in parallel with each other, and the plurality connected in series with each other;
A plurality of LC series resonant circuits each formed by each of the resonators, each formed between adjacent LC parallel resonant circuits, each of which inductor and one capacitor are connected in series;
The resonator disposed on one side of the transmission line is formed between the LC parallel resonant circuit and the LC series resonant circuit by the transmission line, and the transmission line and the each of the tuning bolts corresponding to the resonators respectively. And a plurality of variable capacitors of which the capacitance between the resonators is variable adjusted. The method of claim 5, wherein
The variable capacitor;
The capacitance is roughly adjusted by at least one of the spacing between the housing and the resonator, and the dielectric constant, cross-sectional area and spacing between the transmission line and the resonator, and by the tuning bolt at the spacing between the resonator and the housing cover. Band suppression filter circuit, characterized in that finely adjusted by.

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