KR20050096709A - System for automatically tuning radio frequency filter and method thereof - Google Patents

Abstract

The present invention provides a system for automatically tuning an RF filter, comprising: a waveform analyzer for analyzing and outputting a waveform of an RF filter to be tuned, a tuning machine for loosening or tightening each tuning screw of the RF filter by a control signal, and a waveform analyzer It includes a system controller that receives a waveform output from the output and outputs a control signal to the tuning machine to a waveform matching the preset reference waveform, and filtering on the time domain required for the RF filter to automatically tune the RF filter. Storing the characteristic curve in advance, receiving the filtering characteristic waveform of the RF filter, comparing the characteristic curve with the pre-stored reference characteristic curve on the time domain of the received RF filtering characteristic waveform, and the time domain of the RF filter. Matches characteristic curves and reference characteristic curves It performs a process to tune the filter to the RF.

Description

RF filter automatic tuning system and its method {SYSTEM FOR AUTOMATICALLY TUNING RADIO FREQUENCY FILTER AND METHOD THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can be applied to a manufacturing process of RF filters, and more particularly, to a system and method for tuning RF filters.

RF filters (Dial filter, Cavity filter, Wave guide filter, etc.) have a kind of circuit structure for resonating high frequency, especially ultra high frequency. Resonant circuits by common coils and capacitors are not suitable for forming very high frequencies due to their large radiation losses. The RF filter forms a cavity of a metallic cylinder or cuboid surrounded by a conductor and has a dielectric (DR) or a metal rod therein so that only an electromagnetic field of a natural frequency exists so that resonance of an ultra high frequency wave can be prevented. It has a structure that makes it possible.

The RF filter has a low insertion loss and is advantageous for high output, so it is applied to almost all transmission / reception communication equipments such as mobile communication base stations, repeaters, broadcast repeaters, and satellite communication systems, and is also used for duplexers and bandpass filters. Are employed. Hereinafter, the configuration and operation of the RF filter will be described in detail with reference to the accompanying drawings.

FIG. 1A is an overall perspective view showing the structure of a general RF filter, FIG. 1B is a partially cutaway perspective view of FIG. 1A, and FIG. 1C is a cutaway perspective view along a dashed-dotted line B in FIG. 1A. 1A to 1C, the RF filter 100 first includes a housing 110 forming a body and a cover 160 coupled to an upper surface of the housing 110 to shield the inside thereof. The interior of the housing 110 is divided into a plurality of receiving spaces (six in the example of FIG. 1) by the diaphragm 130, each of the receiving space is a disk-shaped resonant rod formed with a hollow portion for resonating the desired frequency 120 (or dial) is mounted. Input and output connectors 111 and 113 for inputting and outputting wireless signals are installed on the side surface of the housing 110 (the same side in the example of FIG. 1A), and the disc-shaped resonator rods 120 provided in the accommodation spaces of the installed positions, respectively. And are connected by a combined copper wire 115. The diaphragm 130 has coupling windows 131, 132, 133, 134 and 135 which connect the receiving spaces in series from the receiving space to which the input connector 111 is connected to the receiving space to which the output connector 113 is connected. do.

When the disc-shaped resonator rods 120 are mounted in the respective accommodation spaces of the housing 110, the upper end of the housing 110 is sealed by the cover 160. As shown in FIG. 1A, the cover 160 and the housing 110 are mutually connected by screw 179 fastened to a screw fastening hole 169 and a fastening tab 180 formed in a plurality of appropriately corresponding positions, respectively. Can be combined. The disc-shaped resonator rod 120 has been described as being manufactured and mounted separately from the housing 110, but may be manufactured integrally with the housing 110.

The disc-shaped resonator rod 120 includes a resonator rod 121 extending from the bottom of the housing 110 (in this case, an alumina support for supporting the resonator rod 121 at the center may be provided), and an upper end of the resonator rod 121. It consists of a disk 122 extending in the radial direction along the outer circumferential surface. The resonance frequency is determined by the capacitance value and the inductance value formed between the capacitive component and the inductive component, that is, the housing 110, the diaphragm 130, the disc-shaped resonance rod 120, and the cover 160. In order to form the filtering characteristics required for the filter, the shape and size of the accommodation space of the housing 110, the shape, the material and the size of the disc-shaped resonator rod 120, etc. are appropriately designed.

As described above, after the disc-shaped resonator rods 120 are mounted in the respective accommodation spaces of the housing 110, the cover 160 and the housing 110 are combined to produce the RF filter 100. Perform the operation of correcting the error portion caused by the error occurred in the error and the manufacturing part. To this end, a plurality of tuning screws 170 and 175 are fastened to a screw hole (not shown) to adjust the resonance and coupling characteristics of the RF filter 100 in the upper cover 160 of the RF filter 100. do.

The tuning screws 170 and 175 are fastened to a position corresponding to the disc-shaped resonator rod 120 to be used to adjust the resonance characteristics of the resonance tuning screw 170 and the coupling windows 131 to 135. And may be divided into a coupling tuning screw 175 used to adjust coupling characteristics. Tightening or loosening the tuning screws 170 and 175 adjusts the corresponding resonance characteristics (ie, center frequency) and coupling characteristics (ie, frequency band).

Tightening or loosening the tuning screws as described above is made by a skilled worker by hand. The operator checks the output waveform of the RF filter (filtering characteristic waveform in the frequency domain) with a separate waveform analyzer while tightening or loosening the appropriate tuning screw among the plurality of tuning screws. In this case, since the variance of the corresponding adjusting part affects the other parts when adjusting each tuning screw, tuning the filtering characteristics of the whole RF filter by adjusting a plurality of tuning screws is highly dependent on the intuition of the operator. It required a lot of experience. Moreover, the operator manually adjusted the tuning screws, which made the characteristics of each product uneven and required a lot of work time. The human resources required for the tuning of the RF filter and the large amount of time required for the tuning operation contributed to increasing the manufacturing cost of the RF filter and lowering the yield.

Accordingly, an object of the present invention is to provide an automatic tuning system and method for automatically tuning the RF filter and improving the yield of the RF filter.

Another object of the present invention is to provide an automatic tuning system and method for automatically tuning RF filters and allowing the characteristics of each product to be uniform.

In order to achieve the above object, a feature of the present invention is a system for automatically tuning an RF filter, the waveform analyzer for analyzing and outputting the waveform of the RF filter to be tuned, and each tuning screw of the RF filter by a control signal And a system controller for receiving the waveform output from the waveform analyzer and outputting the control signal to the tuning machine to output a waveform matching the preset reference waveform.

According to another aspect of the present invention, there is provided a method for automatically tuning an RF filter, the method comprising: storing a filtering characteristic curve in a time domain required for the RF filter, receiving a filtering characteristic waveform of the RF filter to be tuned; And comparing the characteristic curve and the pre-stored reference characteristic curve on the time domain of the received RF filtering characteristic waveform, and tuning the RF filter to match the characteristic curve and the reference characteristic curve on the time domain of the RF filter. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, specific details of the structure and tuning process of the RF filter are shown, which are provided to help a more general understanding of the present invention, and these specific details may be modified or changed within the scope of the present invention. It will be obvious to those of ordinary skill in the art.

Figure 2a is a schematic overall block diagram of the RF filter automatic tuning system according to an embodiment of the present invention, Figure 2b is a schematic perspective view showing the structure of the tuning machine 240 of Figure 2a for convenience of description The shape is somewhat exaggerated. First, referring to FIG. 2A, the RF filter automatic tuning system according to the present invention includes a waveform analyzer 220 for analyzing and outputting a waveform of the RF filter 400 to be tuned, and each of the RF filters 400 by a control signal. A system for outputting a control signal to the tuning machine 240 so that the tuning machine 240 to loosen or tighten the tuning screw, and the waveform output from the waveform analyzer 220 to receive a waveform matching the preset reference waveform. Controller 210. In the example shown in FIG. 2A, a switch box 230 that appropriately switches a signal path of an appropriate input / output connector of an RF filter 400 to be tuned under the control of the system controller 210 and provides the corresponding input / output signal to the waveform analyzer 220. And a printer 250 for printing the waveform analyzed by the waveform analyzer 250 is shown.

In the RF filter autotuning system having the same configuration, the system controller 210 stores the filtering characteristic data in advance on the time domain read from the RF filter 400 to be tuned by the waveform analyzer 220. golden filter) 's filtering characteristics data. In this comparison, the system controller 210 operates the tuning machine 240 by a tuning algorithm which is preset such that the filtering characteristic data on the time domain of the RF filter 400 matches the filtering characteristic data of the golden filter. 400 to perform a tuning operation.

Hereinafter, the configuration and operation of the RF filter automatic tuning system will be described in more detail. First, the system controller 210 may be configured as a personal computer, and may be manufactured using a 'Pentium3' 500MHz equivalent model or more. The system controller 210 communicates with the waveform analyzer 220, the switch box 2230 and the tuning machine 240 and controls the tuning machine 240 to tune the RF filter 400 in accordance with aspects of the present invention. The program is preinstalled. In the example of FIG. 2A, the system controller 210 communicates with the switch box 230 and the tuning machine 240 in an RS-232C communication method, where a 9-pin D-sub connector is connected. The switch box 230 and the tuning machine 240 are controlled through the COM1 and COM2 communication ports. In addition, the system controller 210 may be connected to the waveform analyzer 220 by a general purpose interface bus (GPIB) cable, and stably communicates through the parallel port.

The waveform analyzer 220 may be configured with Agilent Technologies' 8753ES equivalent or more, and has a function (option 010 mode) for analyzing the output signal of the RF filter 400 in the time domain.

Referring to FIG. 2B, the tuning machine 240 may move on the coordinates according to the control signal of the system controller 210 and move to the position of the tuning screw of the RF filter 400 to be tuned. 242, a motion controller including a portion of the tool 244 for turning the tuning screw of the RF filter 400 clockwise or counterclockwise, a base plate 246 for fixing the RF filter 400, and the like. Mechanical structure and the like. At this time, the tuning screw of the RF filter 400 has a structure of a polygonal (preferably hexagonal) groove, not a general screw structure, as shown in an enlarged circle shown by a dashed line in FIG. 2B. In addition, the tool 244 of the tuning machine 240 is provided with a polygonal (hexagonal) wrench 245 inserted in a form that is properly coupled to the polygonal (hexagonal) groove of the tuning screw of the RF filter 400 as described above. By rotating the hexagon wrench 245 clockwise or counterclockwise, the corresponding tuning screw rotates clockwise or counterclockwise. Referring to the enlarged bar in another circle indicated by a dashed line in Figure 2b, it can be seen that the polygonal wrench 245 is a hexagonal structure.

Each of the RF filters 400 to be tuned above is fixedly seated by a vacuum pad 247 or the like at a precise position preset in the base plate 246 of the tuning machine 240. And information about each RF filter 400 seated at this position, in particular information about the position of each tuning screw is stored in advance in the system controller 210 shown in Figure 2a, the system controller 210 The tuning machine 240 is controlled based on the information on the position of the tuning screw.

2A and 2B, an RF filter autotuning system according to a feature of the present invention may be configured. In addition to the above configuration, the system controller 210, the switch box 230, the waveform analyzer 220 and A power supply unit (not shown) for supplying operation power to the tuning machine 240 may be further provided. In the RF filter automatic tuning system, the system controller 210 controls the tuning machine 240 to find the hexagonal groove positions of the respective tuning screws in the RF filter 400 to be tuned by the tuning machine 240 in an appropriately set order. The hex wrench 245 of the tool 244 is inserted into the hexagonal groove of the found tuning screw. Thereafter, the system controller 210 controls the tool 244 of the tuning machine 240 to rotate clockwise or counterclockwise to tighten or loosen the corresponding tuning screw, so that the characteristic waveform of the RF filter 400 currently being tuned. Match the characteristic waveform of this pre-stored golden filter. Through this process, the tuning of the RF filter 400 is performed. After such tuning, the operator inspects the electrical characteristics of the RF filter 400 in the frequency domain through the waveform analyzer 220 and finishes the product adjusting process. do. Hereinafter, a tuning operation of an RF filter automatic tuning system according to a feature of the present invention having the configuration as described above will be described in detail with reference to the accompanying drawings.

3A and 3B are flowcharts illustrating an RF filter autotuning process according to an embodiment of the present invention, and FIG. 4 is an exemplary structural diagram of an RF filter 400 in which autotuning is performed according to an embodiment of the present invention. First, referring to FIG. 4, referring to the structure of an example RF filter 400 in which a tuning operation is performed, the RF filter 400 includes six disc-shaped resonator rods 420 (or dials) arranged in six series. Each has a structure installed in the receiving space. In addition, the first and second connectors 411 and 413 are installed outside the receiving space at both ends of the RF filter 400 (ie, the outside of the housing), and the disc-shaped resonator rods 420 provided in the receiving space at the corresponding installed positions, respectively. ) Is connected by a combined copper wire. A plurality of tuning screws 170 and 175 are installed on the upper cover of the RF filter 400, and the tuning screws 170 and 175 are respectively resonant tuning screws fastened to positions corresponding to the disc type resonant rods 420. 170 and a coupling tuning screw 175 fastened to a position corresponding to the coupling window provided between each receiving space. In the example shown in FIG. 4, there are six resonance tuning screws 170 and five coupling tuning screws 175. On the other hand, in the circle indicated by the dotted line of Figure 4 is shown that the hexagonal groove is provided on the top of the tuning screw (170, 175).

In an embodiment of the present invention, three receiving space portions connected in series on the first connector 411 side with respect to the center point ('LA' point) of the RF filter 400 and the second connector 413 The filtering characteristics are analyzed by dividing the three receiving space portions connected in series at the side, and each portion divided into the first and second connectors 411 and 413 will be referred to as S11 stage and S22 stage, respectively. In step S11, the 'ga' point coupled to the first connector 411, and the point 'I', 'da', which correspond to the point where the tuning screws 170 and 175 are installed, that is, the coupling window sequentially; Wave analysis and tuning are performed at the 'la' point and '1', '2', and '3' points respectively corresponding to the disc-shaped resonator rods 420 sequentially. Similarly, in step S22, the 'A' point coupled to the second connector 413 and the 'B' and 'C' points corresponding to the points where the respective tuning screws 170 and 175 are installed, that is, the points corresponding to the coupling window sequentially. Waveform analysis and tuning is performed at points 'I', 'II', and 'III', which are points corresponding to the disc resonant rods 420 in sequence.

In FIG. 5, the filtering characteristic required for the RF filter 400, that is, the filtering characteristic curve of the golden filter is illustrated. In FIG. 5 (a) and (b), the filtering characteristic at the S11 stage and the S22 stage in the time domain is illustrated. Curves are shown respectively. Data on the filtering characteristics of the golden filter is previously provided and stored in the system controller 210 as described above. As shown in (a) and (b) of FIG. 5, it can be seen that in S11 and S22, the respective points sequentially correspond to the ridges and valleys of the filtering characteristic curve on the time domain. That is, the points A, B, C, and D of steps S11 and 1, 2, and 3 correspond to the floor and the valley of the filtering characteristic curve of FIG. Point C and points I, II, and III correspond to the ridges and valleys of the filtering characteristic curve of FIG. Accordingly, the filtering characteristic curves of the RF filters 400 to be tuned are compared with the characteristic curves shown in FIGS. 5A and 5B, and the tuning screws 170 of the corresponding points are matched with each characteristic point. 175) to tighten or loosen, so that the characteristic curve as a whole is consistent. As such, by analyzing the filtering characteristic curve of the RF filter 400 in the time domain, accurate tuning is possible for each tuning point of each tuning screw 170 and 175.

3A and 3B, an RF filter autotuning process according to an embodiment of the present invention includes a first tuning process 310 (step 310), which primarily tunes the RF filter 400 according to a predetermined step. After the tuning process (310 process) checks the state of the S11 stage and the S22 stage in the frequency domain to determine the normal and bad state of the first check process (320 process) and the first progressive process (320 process) judged as a result After the second tuning process (330 process), the second tuning process (330 process), the final tuning process after the second tuning process (330 process) and the final tuning process Thereafter, the process checks the state of the S11 and S22 stages in the frequency domain to determine the normal and bad state (step 350).

In the first tuning process 310, the tuning operation of the resonance portion of the S11 stage is performed in step 312, and the tuning operation of the resonance portion of the S22 stage is performed in step 314. The tuning operation of the resonant portion is performed by the filtering characteristic curves of the pre-set golden filter and the filtering characteristic curves of the corresponding RF filter 400 to be matched with points 1, 2, and 3 of S11 stages, and I, II, and III of stages S22. Each resonance tuning screw 170 at the point consists of tightening or loosening sequentially. Thereafter, in step 316, a tuning operation of the coupling part of step S11 is performed, and in step 318, a tuning operation of the coupling part of step S22 is performed. The tuning operation of the coupling portion is filtering tuning of the B, C, S, and C points of the S11 stage so that the filtering characteristic curve of the golden filter matches the filtering characteristic curve of the RF filter 400 to be tuned. This is accomplished by tightening or loosening the screws 175 sequentially.

This tuning operation will be described in more detail with reference to FIGS. 6A, 6B and 6C. 6A, 6B, and 6C show characteristic curves of the RF filter 400 to be tuned. In each of FIGS. 6A, 6B and 6C, (a) has characteristic curves in the frequency domain, and (b) and (c) show time curves. The characteristic curves at the S11 and S22 stages are shown on the domain. Also, the characteristic curves shown by solid lines in (a), (b), and (c) of FIGS. 6A, 6B, and 6C are filtering characteristic curves of the golden filter, and the characteristic curves represented by dotted lines are characteristic of the RF filter 400 to be tuned. It is a curve.

First, a characteristic curve of the RF filter 400 which is not tuned is shown in 6a. As shown, the characteristic curve of the RF filter 400 which is not tuned is substantially inconsistent with the filtering characteristic curve of the golden filter. Can be. In such a state, if steps 312 and 314 are performed to tune the resonant portions of the S11 stage and the S22 stage so that the mismatched portions with the characteristic curve coincide, the characteristic curve of the RF filter 400 is preferably shown in FIG. 6B. As shown in FIG.

FIG. 6B illustrates a characteristic curve of the RF filter 400 in which the resonance portion is tuned. As shown in FIGS. 6B and 6C, the characteristic waveforms are coincident in the floor portion, and FIG. 6B. It can be seen that the characteristic curve of the RF filter 400 tuning on the frequency domain shown by dotted lines in (a) is more similar to the characteristic curve of the golden filter than the state shown in FIG. 6A.

FIG. 6C illustrates a characteristic curve of the RF filter 400 in which the coupling portions of the S11 stage and the S22 stage are tuned by performing the steps 316 and 318 after tuning the resonance portion. As shown in (b) and (c) of FIG. 6C, it can be seen that the characteristic waveforms coincide in both the ridge and valley portions, and thus the characteristic in the frequency domain as shown in (a) of FIG. 6C. It can be seen that the curves are almost identical.

Referring again to FIGS. 3A and 3B, after performing the first tuning step 310 as described above, the first check process 320 is performed to check normal and bad states by checking the states of the S11 and S22 stages in the frequency domain. Process), of course, by checking the coincidence state of the characteristic curve of the RF filter 400 tuning with the golden filter on the frequency domain, it is determined whether the normal and bad. The second tuning process (step 330), which is performed when it is determined that the first check process (320 process) is determined to be defective, first performs the tuning operation of the resonance and coupling portions of the S11 stage in step 332, and then 334. In step S22, the tuning operation of the resonance and coupling parts of the step S22 is performed. In the tuning operation in steps 332 and 334, as shown in FIG. Tighten or loosen the tuning screws 170 and 175 at the points in the order of I-II-B-III-CB-I-II-III.

Thereafter, in step 336, the resonance and coupling portions of the S11 stage are retuned, and in step 338, the resonance and coupling portions of the S22 stage are retuned. In the tuning operation in steps 336 and 338, as shown in FIG. 3B, in the order of 1-na-2-da-3-la-1-2-3 points in step S11, and I- in step S22. Tighten or loosen the tuning screws 170 and 175 at the points in the order of points B-II-C-III-I-II-III.

After the second tuning process 330, the final tuning process 340 is performed. First, in step 342, tighten the tuning screws 170 and 175 of the corresponding points in the order of 1-2-3 points of the S11 stage. The resonant part is then tuned and then the resonant part is tuned in step 348 by tightening or loosening the tuning screws 170 and 175 at the corresponding point in the order of the point I-II-III of step S22.

After the final tuning process (340), the secondary check process (350 process is performed to check the state of the S11 and S22 stages in the frequency domain to determine the normal and bad state, if it is determined that the bad 2 The second tuning process (330 process) and the last tuning process (process 340) may be repeatedly performed to tune again.

As described above, the configuration and operation of the RF filter automatic tuning system according to an embodiment of the present invention can be made. Meanwhile, the above-described description of the present invention has been described with respect to specific embodiments, but various modifications are not departing from the scope of the present invention. It can be done without. Therefore, the scope of the present invention should not be defined by the described embodiments, but by the claims and equivalents of the claims.

As described above, the automatic RF filter tuning method according to the present invention can automatically tune the RF filter, saving human resources and improving work time, thereby reducing the manufacturing cost of the RF filter.

In addition, since the product produced by the RF filter autotuning method according to the present invention exhibits the same uniform characteristics as the duplicated product, it is possible to produce a large amount of products having the same characteristics by producing a golden filter in a minimum optimal state.

And according to the conventional method, it is difficult to increase the production capacity in the short time because the training and experience of manufacturing human resources is required, but the automatic RF filter tuning method according to the present invention is manufactured only by increasing the equipment (tuning machine, controller, waveform analyzer, etc.) The production capacity can be increased in a short time.

1A is an overall perspective view showing an exemplary structure of a general RF filter, FIG. 1B is a partially cutaway perspective view of FIG. 1A, and FIG. 1C is a cutaway perspective view according to a dashed-dotted line B in FIG. 1A.

Figure 2a is a schematic overall block diagram of an RF filter automatic tuning system according to an embodiment of the present invention

Figure 2b is a schematic perspective view showing the structure of the tuning machine of Figure 2a

3A and 3B are flowcharts of an RF filter autotuning process according to an embodiment of the present invention.

4 is an exemplary structural diagram of an RF filter in which an automatic tuning operation is performed according to an embodiment of the present invention.

5 is a graph showing a filtering characteristic curve required for the RF filter of FIG.

6A, 6B, and 6C are graphs illustrating a filtering characteristic curve according to an automatic tuning operation according to an embodiment of the present invention in the RF filter of FIG.

Claims (6)

In a system for automatically tuning RF filters, A waveform analyzer that analyzes and outputs the waveform of the RF filter to be tuned; A tuning machine for loosening or tightening each tuning screw of the RF filter by a control signal, And a system controller for receiving the waveform output from the waveform analyzer and outputting the control signal to the tuning machine such that a waveform matching the preset reference waveform is output. The method of claim 1, And a switch box for switching a signal path of an input / output connector of the RF filter under the control of the system controller to provide a corresponding input / output signal to the waveform analyzer. The tuning machine of claim 1, wherein the tuning machine moves on coordinates according to the control signal of the system controller and moves to a position of a tuning screw of the RF filter. And a motion controller comprising a tool portion for rotating the screw clockwise or counterclockwise, a base plate for securing the RF filter and an instrument structure.  According to claim 3, The tuning screw of the RF filter has a structure of a polygonal groove in the upper portion, the tool portion of the tuning machine is provided with a polygonal wrench inserted in the form coupled to the polygonal groove of the tuning screw, the polygon And rotate the tuning screw by rotating a wrench. In a method for automatically tuning RF filters, Pre-storing the filtering characteristic curve on the time domain required for the RF filter; Receiving a filtering characteristic waveform of the RF filter to be tuned, Comparing the characteristic curve with the pre-stored reference characteristic curve on the time domain of the received RF filtering characteristic waveform; Tuning the RF filter to match the characteristic curve in the time domain of the RF filter with a pre-stored reference characteristic curve. The method of claim 5, Tuning the RF filter to match the characteristic curve on the time domain of the RF filter with a preset reference characteristic curve is characterized by the characteristic on the time domain of the RF filter in the RF filter so that the valleys and the floors of both characteristic curves coincide. A method of loosening or tightening the tuning screws installed at each point affecting the valleys and floors of the curve.