JP3807562B2 - Method and apparatus for adjusting high frequency filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus suitable for adjusting a high frequency filter for selecting a signal of a target frequency used in a high frequency wireless communication device or the like and blocking a signal of an unnecessary frequency to a characteristic as designed.
[0002]
[Prior art]
In order to obtain the characteristics of a filter for selecting a high-frequency signal as designed, the tolerance of each circuit element is usually extremely small. For this reason, the manufacture of the conventional filter uses a means for assembling after adjusting individual parts to a predetermined value, or using parts obtained by processing a highly uniform material with high precision, or after assembling the filter. Individual component adjustments have been made to match the frequency characteristics to the desired characteristics.
[0003]
However, in recent years, there has been a strong demand for miniaturization and high-frequency radio communication equipment, and the miniaturization of filters has been demanded. For this reason, a capacitor or coil is composed of a printed film circuit and a plurality of resonance circuits are integrated, or a plurality of through holes are formed in a dielectric ceramic, a conductor electrode is formed inside, and one end of the through hole is formed. Have been put into practical use, and a high-frequency filter having a configuration in which a plurality of resonance parts equivalently having a quarter wavelength are connected in series has been put to practical use.
[0004]
[Problems to be solved by the invention]
However, since these small high frequency filters are integrated with each circuit element, it is difficult to separate and adjust a plurality of resonating parts, and the pass characteristics of the entire filter are compared with the target characteristics. There were many adjustments.
[0005]
However, in this case, since a plurality of resonating parts are coupled, there is no method for directly confirming which resonating part each peak on the pass characteristic is derived from. Also, if the resonance frequency of one resonance part is changed, the resonance frequency of the other resonance part that is coupled also changes, and the resonance frequency changes even if the degree of coupling between the resonance parts is changed. there were.
[0006]
Furthermore, even if each adjustment location is changed individually, multiple elements (passband characteristics, stopband characteristics, pass flatness, etc.) of the overall frequency pass characteristics change, so predicting the mutual effects of each adjustment element There are problems such as the necessity of adjustment and the absence of a numerical standard for individually determining the optimum point of each adjustment element. In order to obtain the target characteristics, a high degree of skill is required.
[0007]
Japanese Patent Laid-Open No. 7-76910 describes a method of simultaneously adjusting the resonance frequency and the coupling capacitance by deleting one electrode conductor. However, it is necessary to predict the change rate and distribution ratio of a plurality of elements. It is necessary to perform complicated calculations without a clear numerical index every measurement, and there is no change in that skill is required for measurement and adjustment. In practice, trial production and computer simulation are repeated many times for each production lot, and the product shape and electrode shape are corrected by machining, or the mold for molding is changed, thereby changing the variation caused by raw materials and processes. It was customary to correct and reduce the amount of adjustment.
[0008]
The technique disclosed in Japanese Patent Laid-Open No. 7-288410 is an example of machining. However, even in that case, it is necessary to make adjustment while confirming the frequency pass characteristic of the filter, and the skill is still necessary. Further, since a metal grinding tool is usually used for electrode trimming, characteristic measurement cannot be performed during trimming, and the trimming and characteristic measurement are alternately performed. The adjustment work is not a simple flow, and it is a work of going back and forth while looking at the balance of the overall frequency pass characteristics, so the efficiency does not increase and automation is difficult.
[0009]
As another problem, since the means for measuring the characteristics is substantially limited to the method performed through the input / output terminals of the high frequency filter, the adjustment procedure is extremely complicated when the adjustment work area overlaps with the input / output terminals. It will be something. In JP-A-7-202511, a dummy measurement electrode is provided to avoid this problem. However, if the dummy electrode is connected to or close to the shielding ground conductor after the filter is adjusted, the adjustment is shifted. In this prior art, means for covering the dummy electrode with the insulating tape is disclosed. However, if the insulating film is covered with the insulating tape, floating coupling or signal leakage occurs through the dummy electrode and the insulating tape. In addition, there is a problem that the housing must be moved away from the position where the dummy electrode is located, and the size of the device is greatly reduced.
[0010]
As an attempt to separate and adjust each resonance part, Japanese Patent Application Laid-Open No. 7-336110 discloses that an adjacent resonance part is short-circuited to a ground potential by a mutual interference prevention short-circuit plate to adjust the resonance frequency of each resonance part. A method has been proposed. In this method, troublesome trials, simulations, and machining work in advance can be omitted. However, even with this method, it is impossible to measure and adjust the coupling between the resonating parts and the coupling between the resonating part and the input / output terminals, and the fluctuation of the coupling degree causes the fluctuation of the resonance frequency after removing the interference prevention short-circuit plate. In the end, it was reflected as it was, and eventually adjustment of the conventional method was necessary.
[0011]
An object of the present invention is to provide a high-frequency filter having a structure in which a plurality of resonance parts are connected in cascade, without considering mutual interference, the resonance frequency of each resonance part, which is an individual adjustment element, the degree of coupling between the resonance parts, To provide an adjustment method and an adjustment device capable of individually measuring and adjusting the degree of coupling with input / output terminals.
[0012]
Another object of the present invention is to obtain a high frequency filter having a desired frequency characteristic by simply adjusting each index to a predetermined value in a high frequency filter having a structure in which a plurality of resonance parts are connected in cascade. It is providing the adjustment method and adjustment apparatus which can be performed.
[0013]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention adjusts the coupling capacitance between two adjacent resonating units that are selected and effective when adjusting a high-frequency filter having a structure in which a plurality of resonating units are connected in cascade to a target characteristic. To do. Next, after the step, the resonance frequency of each resonance unit is adjusted.
[0014]
That is, as the first step, the coupling amount between the resonance parts is adjusted. Adjustment of the coupling capacitance is performed by trimming the electrodes formed between the resonating parts using the transmission null frequency as an index. When the coupling capacitance is changed, the resonance frequency changes with the transmission null frequency, but is ignored at this stage.
[0015]
In the next step, the resonance frequency of each resonance unit is adjusted. The resonance frequency is adjusted by changing the ground load capacity of the resonance part. This adjustment changes the resonant frequency, but does not change the transmitted null frequency at all. Therefore, the two indexes of the transmission null frequency and the resonance frequency are adjusted independently.
[0016]
According to this adjustment means, it is possible to individually adjust the resonance frequency of each resonance part, which is an individual adjustment element, the degree of coupling between the resonance parts, and the degree of coupling between the resonance part and the input / output terminals without considering mutual interference. . In addition, a high frequency filter having a desired frequency characteristic can be obtained simply by adjusting each index to a predetermined value.
[0017]
Other objects, configurations, and advantages of the present invention will be described in more detail with reference to the accompanying drawings. The accompanying drawings do not imply any limitation.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an external perspective view of a high frequency filter to which the present invention is applied, and FIG. 2 is a cross-sectional view of the high frequency filter shown in FIG.
[0019]
The illustrated high-frequency filter is configured by sharing the dielectric ceramic 10 and cascading the four resonating parts 31 to 34 on the dielectric ceramic 10. The resonating portions 31 to 34 form through holes in the common dielectric ceramic 10 at intervals, and form metallized conductors on the inner peripheral surface of the through holes 310 to 340 and the outer peripheral surface of the dielectric ceramic 10. Is made up of. Of the both end faces where the through-holes are opened, one end face is an open end, and the other end face is a short-circuit end covered with the external conductor 20. This structure is well known to those skilled in the art.
[0020]
The through-hole 310 is unfolded on the open end side, and electrodes 311 to 314 are provided for adjustment in the unfolded portion. Similarly, the through hole 320 is also unfolded on the open end side, and electrodes 321 to 324 are provided in the unfolded portion. The through hole 330 is also unfolded on the open end side, and electrodes 331 to 334 are provided in the unfolded portion. Similarly, the through hole 340 is unrolled on the open end side, and electrodes 341 to 344 are provided in the unfolded portion.
[0021]
The electrode 313 of the resonance unit 31 is an electrode 321 of the resonance unit 32, the electrode 323 of the resonance unit 32 is an electrode 331 of the resonance unit 33, and the electrode 333 of the resonance unit 33 is an electrode 341 of the resonance unit 34, and a dielectric ceramic. It faces through 10 thin parts. The electrodes 311 and 312 of the resonance unit 31, the electrodes 322 and 324 of the resonance unit 32, the electrodes 332 and 334 of the resonance unit 33, and the electrodes 342 and 343 of the resonance unit 34 are external grounds formed on the outer peripheral surface of the dielectric ceramic 10. The conductor 20 is opposed to the dielectric ceramic 10 through a thin portion.
[0022]
An input / output terminal 21 and an input / output terminal 22 are provided on one side of the dielectric ceramic 10. The input / output terminal 21 is provided on a side portion of the resonance unit 31 and faces the electrode 314 applied to the unfolded portion of the resonance unit 31. The input / output terminal 22 is provided on the side of the resonance part 34 and faces the electrode 344 provided on the unfolded part of the resonance part 34. Around the input / output terminal 21 and the input / output terminal 22, gaps G1 and G2 that are electrically insulated from the external ground conductor 20 are provided. The input / output terminal 21 and the input / output terminal 22 are reversible with respect to input / output.
[0023]
FIG. 3 is an equivalent circuit diagram of the high-frequency filter shown in FIGS. In the figure, the capacitance Cin is an input / output coupling capacitance, the capacitances C12, C23 and C34 are coupling capacitances between the resonance parts, the capacitances C01 to C04 are ground load capacitances, and the capacitance Cout is an input / output coupling capacitance. The input / output coupling capacitance Cin is generated between the input / output terminal 21 and the electrode 314 of the resonance unit 31. The coupling capacitance C12 is between the electrode 313 of the resonance unit 31 and the electrode 321 of the resonance unit 32, the coupling capacitance C23 is between the electrode 323 of the resonance unit 32 and the electrode 331 of the resonance unit 33, and the coupling capacitance C34 is resonance. It occurs between the electrode 333 of the part 33 and the electrode 341 of the resonance part 34, respectively. The input / output coupling capacitance Cout is generated between the input / output terminal 22 and the electrode 344 of the resonance unit 34.
[0024]
The ground load capacitance C01 is generated between the electrodes 311 and 312 of the resonance unit 31 and the external ground conductor 20, and the ground load capacitance C02 is generated between the electrodes 322 and 324 of the resonance unit 32 and the external ground conductor 20. The ground load capacitance C03 is generated between the electrodes 332 and 334 of the resonance unit 33 and the external ground conductor 20, and the ground load capacitance C04 is generated between the electrodes 342 and 343 of the resonance unit 34 and the external ground conductor 20. .
[0025]
FIG. 4 is a more detailed equivalent circuit diagram of the high-frequency filter shown in FIGS. The resonating units 31 to 34 are expressed as parallel circuits of inductor components L1 to L4 and capacitor components C11 to C44. The ground load capacitors C01 to C04 are connected in series to the LC parallel circuit described above. A symbol M is a mutual inductive coupling coefficient between the resonance parts.
[0026]
As described above, in this type of high-frequency filter, the electrodes 311, 312, 322, and 324 that generate the ground load capacitances C01 to C04 facing the external ground conductor 20 are provided on the open ends of the resonating units 31 to 34. 332, 334, 342, 343, input / output coupling capacitance between the electrodes 313, 321, 323, 331, 333, 341 and the input / output terminals 21, 22 that generate coupling capacitances C 12 to C 34 between the adjacent resonance parts. There are input / output electrodes 314 and 344 that generate Cin and Cout. In the present invention, these capacitor electrodes are trimmed and removed to adjust the target characteristics.
[0027]
FIG. 5 is a diagram showing a measurement method according to the present invention, and FIG. 6 is a diagram showing the measurement method shown in FIG. First, two resonance parts 32 and 33 are selected from four resonance parts 31 to 34 connected in cascade. The other resonating parts 31, 34 adjacent to the two resonating parts 32, 33 are short-circuited to the high frequency ground potential to act as shield electrodes. Thereby, the influence of the resonance parts 31 and 34 is prevented, and the two resonance parts 32 and 33 to be adjusted are selected. As the short-circuit means, a short-circuit pin composed of a metal member such as a metal pin can be used.
[0028]
The first high-frequency probe 61 is loosely coupled to the first resonating unit 32 out of the two resonating units 32 and 33, and the second high-frequency probe 11 is tightly coupled to the second resonating unit 33. Hereinafter, the first high-frequency probe 61 is referred to as a loosely coupled probe 61, and the second high-frequency probe 11 is referred to as a tightly coupled probe 11. Here, loose coupling means the coupling that can transmit a minute high-frequency power without affecting the operation of the resonance part and maintaining a substantially no-load state. Specifically, it is in a contactless and close position. Coupling by placing a probe or coupling through an insulator having a low dielectric constant corresponds to this. The tight coupling means a strong coupling in which the load effect due to the coupling with the resonance part affects the operation. The high-frequency ground potential means a potential having the same effect as that of ground with respect to a high frequency, and includes a potential on which a direct current or a low-frequency signal is carried. Hereinafter, it is referred to as ground potential for short.
[0029]
FIG. 7 shows the reflection characteristic of the tightly coupled probe 11 obtained in the measurement state of FIGS. 5 and 6, and FIG. 8 also shows the transfer characteristic from the tightly coupled probe 11 to the loosely coupled probe 61. Similar transfer characteristics can be obtained even if the transmission direction is reversed.
[0030]
One resonance frequency fr can be read from the reflection characteristic of FIG. 7, and the frequency fa of one peak P1 and one valley V1 (transmission null) can be read from the transfer characteristic of FIG. As shown in the figure, the resonance frequency fr and the transmission peak frequency fp are substantially the same. The loosely coupled probe 61 needs to be in an electric field detection mode with a high impedance at the tip. No transmission null was observed in the loop coil type magnetic field detection mode.
[0031]
In the adjustment, the coupling amount C23 between the resonating parts 32-33 is adjusted in the state shown in FIGS. The coupling capacitance C23 is adjusted by trimming the electrode 323 or 331 formed between the resonance portions 32-33.
[0032]
FIG. 9 is a diagram showing changes in the resonance frequency and the transmission null frequency when the coupling capacitance C23 between the resonance portions 32-33 is changed. As shown in FIG. 9, when the coupling capacitance C23 is changed, the transmission null frequency is changed along with the resonance frequency. However, at this stage, the change in the transmission null frequency due to the change in the coupling capacitance C23 is ignored.
[0033]
Next, the resonance frequency of the resonance unit 32 is adjusted. The resonance frequency is adjusted by changing the ground load capacitance C02 of the resonance unit 32. This adjustment changes the resonant frequency, but does not change the transmitted null frequency at all. FIG. 10 is a diagram illustrating changes in the resonance frequency and the transmission null frequency of the resonance unit 32 when the ground load capacitance C02 is changed.
[0034]
On the other hand, even if the ground load capacitance C03 of the resonance unit 33 is changed, the resonance frequency of the resonance unit 32 hardly changes and the transmission null frequency does not change at all. FIG. 11 is a diagram illustrating changes in the resonance frequency and the transmission null frequency of the resonance unit 32 when the ground load capacitance C03 is changed. Therefore, for the resonance unit 32, the resonance frequency and the transmission null frequency after obtaining the adjustment step are index frequencies. The linearity of these index frequencies with respect to the capacity change amount is maintained in a wide range.
[0035]
In order to adjust the resonance frequency and the transmission null frequency of the resonance unit 33, the positions of the loosely coupled probe 61 and the tightly coupled probe 11 are interchanged in FIGS. 5 and 6, and the same adjustment steps as the resonance unit 32 are executed. .
[0036]
By going through the adjustment process, the two indexes of the transmission null frequency and the resonance frequency are adjusted independently in each of the resonance units 32 and 33.
[0037]
According to this adjustment means, the resonance frequency of each of the resonance units 32 and 33, which are individual adjustment elements, and the degree of coupling between the resonance units 32 and 33 are individually adjusted without considering mutual interference between the resonance units 32 and 33. obtain. In addition, it is possible to provide a basic technique for obtaining a high-frequency filter having a target frequency characteristic only by adjusting each index to a predetermined value.
[0038]
As an actual measurement example, FIGS. 12 and 13 show the transfer characteristics when the ground load capacitance C02 of the resonance unit 33 is changed with the same configuration as in FIGS. FIG. 12 shows the transfer characteristic before adjusting the ground load capacity C02, and FIG. 13 shows the transfer characteristic after adjustment. The transmission null frequency does not change before and after adjustment.
[0039]
Note that even when both the tightly coupled probe 11 and the loosely coupled probe 61 are tightly coupled, the transmission null frequency can be measured and shows the same behavior as above, but the resonant frequencies of the two resonating parts are observed. Thus, there are problems such as inseparability and increased influence of errors due to direct coupling between the tightly coupled probe 11 and the loosely coupled probe 61. If both the tightly coupled probe 11 and the loosely coupled probe 61 are loosely coupled, the signal intensity is weakened and the transmitted null frequency is buried in noise, which cannot be measured.
[0040]
As described above, the operation in the two simplified models as the resonance parts 32 and 33 can be explained as follows when the resonance part 32 is considered as a center.
[0041]
(A) In the measured resonance frequency, the resonance of the resonance part 32 is observed independently. The load of the resonance unit 32 is only the loosely coupled probe 61. The loosely coupled probe 61 is substantially almost unloaded and has a small power loss. On the other hand, since the resonance part 33 is directly loaded with the tightly coupled probe 11, the power loss is large. For this reason, the resonance of the resonance part 33 becomes shallow, and as a result, only the resonance of the resonance part 32 is observed. Further, when the difference in load impedance is large as described above, the interference of the resonance frequency becomes small.
[0042]
(B) The change in the ground load capacitance C03 of the resonance unit 33 coupled to the tightly coupled probe 11 does not affect the resonance frequency or the transmission null frequency measured in the resonance unit 32.
[0043]
(C) The transmission null does not actually have a substance to block the signal, and the signal cancels at a frequency at which the capacitive coupling between the two resonating parts 32-33 and the magnetic inductive coupling are equal, This is a phenomenon in which no signal is apparently transmitted. Probing with magnetic coupling does not cancel. If the coupling state between the resonating parts 32 and 33 is kept constant, even if the ground load capacitance C03 of the resonating part 33 changes and the resonance frequency changes, the transmission null frequency of the resonating part 32 is not affected.
[0044]
(D) These phenomena can be seen in both the distributed constant circuit and the lumped constant circuit if the high-frequency filter has the same configuration.
[0045]
Even when three or more effective resonance parts exist in a coupled state, if the above measurement is performed, individual adjustment capacitors can be adjusted independently using the transmission null frequency and the resonance frequency as indices.
[0046]
Next, an adjustment method will be described with reference to FIGS. In the figure, an arrow display indicates an adjustment target, and a T-shaped display indicates adjusted. The high-frequency filters shown in these drawings are those shown in FIGS. 1 to 4, and reference numerals not shown in FIGS. 14 to 21 are supplemented by FIGS. 1 to 4.
[0047]
In FIG. 14, the loosely coupled probe 61 is coupled to the resonating unit 31 at the leftmost end (in the drawing) of the resonating units 31 to 34, and the tightly coupled probe 11 is coupled to the adjacent resonating unit 32. The resonance unit 33 is short-circuited to the ground potential by the short-circuit pin 52. As a result, the electrode 331 (see FIGS. 1 and 2) of the resonance unit 33 acts as a shield conductor, so that the resonance units 33 and 34 are electrically disconnected from the resonance units 31 and 32. In this state, the transfer characteristic between the tightly coupled probe 11 and the loosely coupled probe 61 is measured, the transmitted null frequency is obtained, the electrode 313 is trimmed so that this index becomes a predetermined value, and the coupling capacitance C12 is adjusted. . At this time, the resonance frequency also changes at the same time, but is ignored at this stage. As a result, the coupling capacitance C12 is set to the target value.
[0048]
In FIG. 15, the input / output terminal 21 is opened to electrically disconnect the input / output coupling capacitor Cin. From the reflection characteristics of the tightly coupled probe 11, the resonance frequency of the resonance unit 31 is obtained, and the electrode 311 or 312 is trimmed so that the index becomes a predetermined value, and the ground load capacitance C01 is adjusted. Since the transmission null frequency does not change at this stage, the two indexes of the transmission null frequency and the resonance frequency are adjusted independently.
[0049]
In FIG. 16, the input / output terminal 21 is short-circuited to the ground potential by the short-circuit pin 51. Since the input / output coupling capacitance Cin is added in parallel to the ground load capacitance C01, the resonance frequency changes. The electrode 314 is trimmed so that the resonance frequency becomes a second predetermined value, and the input / output coupling capacitance Cin is adjusted.
[0050]
Through the adjustment process, the coupling capacitance C12, the ground load capacitance C01, and the input capacitance Cin are adjusted.
[0051]
In FIG. 17, the tightly coupled probe 11, the loosely coupled probe 61, and the short-circuit pins 51 and 52 are moved by one pitch in the arrangement direction of the resonance units 31 to 34. The resonance part 34 is short-circuited to the ground by the short-circuit pin 52. The tightly coupled probe 11 and the loosely coupled probe 61 are coupled to the resonance unit 33 and the resonance unit 32, respectively. Further, the resonance part 31 is short-circuited to the ground with the short-circuit pin 51. In this state, the coupling capacitance C23 is adjusted using the transmission null frequency as an index, as described with reference to FIG. The coupling capacitor C23 is adjusted by trimming the electrode 323 of the resonance unit 32 or the electrode 331 of the resonance unit 33.
[0052]
Next, in FIG. 18, the ground load capacity C02 is adjusted using the resonance frequency as an index. Actually, since the coupling capacitance C12 is added in parallel with the ground load capacitance C02, the resonance frequency is displaced from the original value by that amount. However, since the coupling capacitance C12 has been adjusted at this stage, If a predetermined resonance frequency including the above is set, there is no problem. The ground load capacitance C02 is adjusted by trimming the electrode 322 or 324 of the resonance unit 32.
[0053]
Next, in FIG. 19, the tightly coupled probe 11, the loosely coupled probe 61, and the short-circuit pins 51 and 52 are moved by one pitch in the arrangement direction of the resonating units 31 to 34. Adjust C03. However, in this case, since there is no resonance part to be separated outside the resonance part 34, only the resonance part 32 is short-circuited to the ground. The coupling capacitance C34 is adjusted by trimming the electrode 333 of the resonance unit 33 or the electrode 341 of the resonance unit 34. The ground load capacitance C03 is adjusted by trimming the electrode 332 or 334 of the resonance unit 33.
[0054]
Next, in FIG. 20, the input / output terminal 22 is opened, and the input / output coupling capacitor Cout is electrically disconnected. The tightly coupled probe 11 is coupled to the resonance unit 33, and the resonance unit 32 is short-circuited to the ground by the short-circuit pin 51. In this state, the ground load capacity C04 is adjusted using the resonance frequency as an index. The ground load capacitance C04 is adjusted by trimming the electrode 342 or 343.
[0055]
Next, in FIG. 21, the input / output terminal 22 is short-circuited to the ground potential by the short-circuit pin 52. Since the input / output coupling capacitance Cout is added in parallel to the ground load capacitance C04, the resonance frequency changes. The input / output coupling capacitance Cout is adjusted so that the resonance frequency becomes the second predetermined value. The input / output coupling capacitance Cout is adjusted by trimming the electrode 344.
[0056]
Through the above procedure, trimming of all the adjustment electrodes is completed, and transmission characteristics as shown in FIG. 22 can be obtained by connecting impedance matched transmission lines to the input / output terminals 21 and 22. can get. What is important is to adjust the coupling capacitance prior to the resonance frequency using the transmission null frequency as an index. Conversely, independent adjustment is not possible.
[0057]
Note that a loosely coupled probe is not used for measuring the resonance frequency, but it is not necessary to remove it. This is because resonance is not affected by the definition of loose coupling. In this description, the loosely coupled probe is arranged on the side where the resonance frequency is measured. However, if the transmission null frequency and the resonance frequency are not measured simultaneously, the probe can be disconnected at the time of measuring the resonance frequency. Further, if the condition that can prevent direct coupling between the probes is satisfied, two probes can be tightly coupled, and the measurement signal-to-noise ratio can be improved.
[0058]
Opening / short-circuiting of the input / output terminals 21 and 22 is irrelevant to the measurement except at the specified stage. The metal member for short-circuiting the resonance part to the ground is not limited to the pin shape, and a deformed member such as a leaf spring shape or a block shape can be used if the floating inductance is sufficiently small.
[0059]
In the above description, the number of the resonance parts is four. However, the present invention can be applied to all cases where the number of the resonance parts is two or more. Thus, the adjustment of the coupling capacitance between the resonance parts, the adjustment of the ground load capacitance with the input / output terminal open, and the adjustment of the input / output coupling capacitance with the input / output terminal shorted to the ground may be sequentially performed.
[0060]
Further, the shape of the input / output terminals 21 and 22 is not limited, and a configuration in which the input / output terminals are mounted after adjustment of a single filter as disclosed in JP-A-7-202511 can be applied. In this case, adjust the coupling capacitance between the resonance parts and the resonance frequency without attaching the input / output terminals, and then connect the input / output terminals with the ground short-circuited, and input / output using the displacement of the resonance frequency as an index. Adjust the bond. A dummy electrode for checking the filter characteristics during adjustment is not necessary.
[0061]
As another modification of the present invention, the coupling capacitor electrode trimming and the ground load capacitor electrode trimming can be separated into separate steps. In this case as well, the step of adjusting the coupling capacitance between all the resonance parts using the transmission null frequency between the two probes as an index, the step of adjusting the ground load capacitance using the resonance frequency as an index, and the input / output coupling capacitance It carries out in order of the process to adjust. In addition, when the steps are separated in this way, there is no restriction on the adjustment order of the resonance part arrangement, and adjustment can be performed from any resonance part.
[0062]
In the description so far, the example of the shape in which the electrodes of the coupling capacity and the ground load capacity between the resonance parts are separated is used, but as described in JP-A-7-76910, the open end of the resonance part is used. The present invention can be applied even when the electrode has a cylindrical shape and the coupling capacity and the ground load capacity are not separated. If the trimming sensitivity for each of the trimming positions of the two indices of transmission null frequency and resonance frequency is obtained in advance, the trimming position and the required trimming amount can be predicted by the computer from the displacement of each measured index from the target value. If trimming is started based on this prediction, and dynamic correction is performed while measuring during trimming, two elements can be adjusted simultaneously by one trimming.
[0063]
Any specific adjustment means can be used as long as it satisfies the above-described factors, and both inductive and capacitive coupling can be adjusted for adjusting the degree of coupling. However, in general, when comparing the manufacturing accuracy of magnetic inductive elements (inductance) and capacitive elements (capacitance) in high-frequency filters with a small integrated structure and LC filters with printed films, inductance is a macro such as element shape or conductor pattern shape. On the other hand, the capacitance is determined by factors such as the thickness of the dielectric film or the thinned portion of the dielectric, the dielectric constant distribution, and the like, and the accuracy is usually lower than the macro shape accuracy. For this reason, variation in capacitance is often the cause of characteristic variation, and it is desirable to adjust the capacitance. To change the capacitance, there are a method of changing the electrode area and a method of moving the electrode metal, both of which can be adopted in the present invention. When trimming to remove the electrode conductor to change the electrode area, using an electrically conductive grinding tool makes it impossible to measure the transmitted null frequency and resonance frequency during the grinding operation. Adjustment and measurement can be performed at the same time by using an electrically non-conductive material for the tool in contact or by removing the electrode (trimming) in such a way that other metals do not contact the electrode by means such as sandblasting or laser beam. Therefore, it is advantageous for determining the adjustment end point.
[0064]
Further, the input / output terminals 21 and 22 are not indispensable when adjusting the coupling degree or the resonance frequency. When adjusting the degree of coupling with the terminal, the terminal is simply grounded, and it is not necessary to pass a high-frequency signal. This increases the degree of freedom in selecting the terminal structure and adjustment method.
[0065]
If a measurement electrode that is capacitively coupled to all the resonance parts is provided so that a tightly coupled probe and a loosely coupled probe can be applied from a position away from the trimming work area, the degree of freedom in the trimming process is increased and workability is improved. This electrode can be used for the input / output terminals 21 and 22. When the resonance frequency is adjusted, the measurement electrode coupled to the adjusted resonance part is short-circuited to the ground. Therefore, the electrodes not used for the input / output terminals 21 and 22 are short-circuited to the ground after the adjustment, and are used as a part of the ground shield conductor. Thereby, stray coupling and signal leakage due to the measurement electrode can be prevented. However, it is desirable that the conductor to be short-circuited to the ground should avoid a position straddling between the resonance parts. Otherwise, a high-frequency current is generated across the resonance portion in the external ground conductor, and the degree of coupling changes. In addition, when the measurement electrodes of the adjacent resonance parts are on the same side surface of the filter, direct coupling between the probes becomes a problem. Therefore, it is desirable to provide the measurement electrodes alternately on the two side surfaces.
[0066]
Generally, probes with a characteristic impedance of 50Ω can be used as the probe to be tightly coupled to the resonance part. However, the load is too heavy as it is, and the adjacent resonance part is affected and the assumption of no load is lost. When the resonance frequency cannot be obtained correctly, it is desirable to insert an impedance element such as a resistor, a capacitor or a coil in series near the probe tip, thereby increasing the driving impedance. Excessive reflection due to the insertion impedance element can be corrected on the measuring instrument side. However, when the driving impedance exceeds 800Ω, the measurement signal is attenuated and mutual interference at the resonance frequency is recognized.
[0067]
Next, a measurement apparatus suitable for carrying out the adjustment method according to the present invention will be described with reference to specific examples.
[0068]
A. Example 1
The present invention is applied to a high-frequency filter having two resonance parts. FIG. 23 is a perspective view of the high-frequency filter used in Example 1, and FIG. 24 is a cross-sectional view of the high-frequency filter shown in FIG. The illustrated high-frequency filter includes two resonating units 31 and 32. Most of the outer surface of the dielectric ceramic 10 is covered with an outer conductor 20 that is at ground potential. In each of the two resonating portions 31 and 32, the dielectric ceramic 10 is thinned on the open end side to generate a ground load capacity and a coupling capacity.
[0069]
The input / output terminal 21 is coupled to the resonance part 31 and the input / output terminal 22 is coupled to the resonance part 32 via a thin part of the dielectric ceramic 10.
FIG. 25 shows a measuring device for the high-frequency filter shown in FIGS. In the figure, the shield plate 40 provided with the trimming window 41 is movable in the directions of arrows X1 and X2, and the trimming window 41 can be positioned on the open ends of the resonance portions 31 and 32.
[0070]
Probes 71 and 72 and short-circuit pins 51 and 52 are opposed to the input / output terminal 21 and the input / output terminal 22. The probes 71 and 72 and the short pins 51 and 52 are driven in the directions of the arrows X1 and X2. A tightly coupled probe is in contact with the input / output terminal 21 or the input / output terminal 22, and a loosely coupled probe is in contact with the input / output terminal 21 or 22 without contact. The shield plate 40 is connected to the ground potential.
[0071]
The trimming operation is performed by inserting a rotating grindstone 91 as an electrically non-conductive cutting tool through the trimming window 41 on the open ends of the resonance portions 31 and 32. The rotating grindstone 91 rotates in the direction of the arrow a1. About the said high frequency filter, the predicted value of the resonant frequency or the transmission null frequency was calculated | required by computer simulation.
[0072]
Next, when adjusting the frequency of the high-frequency filter using the adjusting device described above, as shown in FIG. 26, the trimming window 41 is placed on the resonating unit 31, and the probe 71 is loosely coupled to the input / output terminal 21, A probe 72 is tightly coupled to the input / output terminal 22. Therefore, the probe 71 functions as a loosely coupled probe and the probe 72 functions as a tightly coupled probe. The short-circuit pins 51 and 52 are disconnected from the input / output terminal 21 and the input / output terminal 22, and the electrode 313 is trimmed while monitoring the transmission frequency characteristics between the two probes 71 and 72, and the transmission null frequency is set. Set to a predetermined value. The trimming operation was performed by inserting a rotating grindstone 91 through the trimming window 41 on the open ends of the resonance portions 31 and 32. FIG. 27 shows an electrical circuit diagram in this case. By this trimming operation, the coupling capacitance C12 between the resonance portions 31 and 32 is adjusted.
[0073]
Next, the electrode 312 or 314 of the resonating unit 31 is trimmed while monitoring the reflection frequency characteristics of the probe 72 constituting the tightly coupled probe while the input / output terminal 21 is electrically opened, and the ground of the resonating unit 31 is grounded. The load capacity C01 is adjusted. Thereby, the resonance frequency of the resonance part 31 is adjusted to a predetermined value. The probes 71 and 72 and the short-circuit pins 51 and 52 may be at the positions shown in FIG. FIG. 28 shows an electric circuit diagram in this adjustment step.
[0074]
Next, as shown in FIG. 29, the input / output terminal 21 is short-circuited to the ground potential by moving the short-circuit pin 51 in the direction of the arrow X <b> 1, and the electrode 311 facing the input / output terminal 21 of the resonance unit 31. To trim. Thus, the input / output coupling capacitance Cin generated between the input / output terminal 21 and the electrode 311 is adjusted, and the resonance frequency is adjusted to the second predetermined value. FIG. 30 shows an electric circuit diagram in this adjustment step.
[0075]
Next, as shown in FIG. 31, the shorting pin 51 is moved in the direction of the arrow X2 to retract from the high frequency filter, and the probe 72 that has been tightly coupled is moved in the direction of the arrow X1 to retract from the high frequency filter. . Further, the shield plate 40 is moved in the direction of the arrow X1, and the trimming window 41 is placed on the resonance part 32. Further, the probe 71 is moved in the direction of the arrow X1 to be tightly coupled to the input / output terminal 21. Then, with the input / output terminal 22 in an open state, while monitoring the reflection frequency characteristics of the probe 71 that is closely coupled, the electrode 322 (or 324) of the resonance unit 32 is trimmed to adjust the resonance frequency to a predetermined value. FIG. 32 shows an electric circuit diagram in this adjustment step.
[0076]
Next, as shown in FIG. 33, the shorting pin 52 is moved in the direction of the arrow X2 to contact the input / output terminal 22, thereby short-circuiting the input / output terminal 22 to the ground potential. In this state, the electrode 323 facing the input / output terminal 22 of the resonance unit 32 is trimmed to adjust the resonance frequency to the second predetermined value. FIG. 34 shows an electric circuit diagram in this adjustment step.
[0077]
It should be noted that even when both probes 71 and 72 are tightly coupled when adjusting the coupling degree, there is no direct coupling between the probes in this embodiment, so there was no problem, but the above procedure with little movement of the apparatus was used. Do.
[0078]
Although adjustment is possible even if an electrically conductive material made of cemented carbide is used for the cutting tool 91, alternating work of measurement and grinding is forced. Measurement and adjustment can be performed in parallel even with sandblasting and electrode grinding trimming with a laser beam, improving work speed. The pass characteristics of the filter after adjustment showed very good agreement with the design prediction.
[0079]
B. Example 2
35 is a perspective view of a high-frequency filter to which the present invention is applied, and FIG. 36 is a cross-sectional view of the high-frequency filter shown in FIG. The illustrated high-frequency filter is configured by sharing the dielectric ceramic 10 and cascading the eight resonating parts 31 to 38 on the dielectric ceramic 10. The structure of the resonance parts 31 to 38 is not different from the high-frequency filter shown in FIGS. 1 and 2 in the basic configuration. The difference is that the resonance parts 31 to 34 and the resonance parts 35 to 38 have different shapes of through holes appearing on the open end face, and the resonance parts 31 and 38 located at both ends and the resonance part 34 located in the middle. Are provided with input / output terminals 21, 24 and 28, and accordingly, a high frequency filter constituted by the resonance parts 31 to 34 and a filter constituted by the resonance parts 35 to 38 are provided. It can be considered as an integrated structure.
[0080]
37 is a diagram showing an adjustment device suitable for adjusting the high-frequency filter shown in FIGS. 35 and 36, and FIG. 38 is a partial plan view of the adjustment device shown in FIG.
[0081]
As shown in FIG. 37 and FIG. 38, loosely coupled probes 61-67 are arranged at positions that are close to each other but do not overlap with the trimming electrodes, corresponding to each of the resonating units 31-38. FIG. 38 shows loosely coupled probes 61 to 65 among them. However, since the corresponding loosely coupled probe is not necessary for the resonance part having the last adjustment order, it is not arranged. A plurality of loosely coupled probes are installed, but can be switched by a high-frequency switch, and only one is used at a time. No influence was observed due to the presence of a loosely coupled probe that was not used.
[0082]
Each input / output terminal 21, 24, 28 is provided with movable short-circuit pins 71, 72, 73 (the short-circuit pin 73 is not shown), and the input / output terminals 21, 24, 28 are open and external conductors (ground potential). The short circuit to) is switched.
[0083]
A shield plate 40 having an adjustment trimming window 41 is prepared, and a grounding short-circuit pin 51 is provided at a position corresponding to the arrangement pitch of the resonance portions 31 to 38 on one side of the window 41, and the opposite side is densely provided. The coupling probe 11 and the grounding short-circuit pin 52 are provided at the resonance portion arrangement pitch. The ground short-circuit pin 51, the tightly coupled probe 11, and the ground short-circuit pin 52 are guided from the upper surface to the lower surface side of the shield plate 40 through holes provided in the shield plate 40. At this time, the outer sheath shield and the short-circuit pin of the probe are brought into contact with the shield plate 40 and grounded. The ground short-circuit pin 51, the tightly coupled probe 11 and the ground short-circuit pin 52 are supported by a spring 45 and can be moved in the vertical direction by a spring action.
[0084]
When the driving impedance of the tightly coupled probe 11 is 50Ω, the resonance Q is lowered and the resonance becomes shallow. Therefore, a 1 pF capacitor is inserted in series near the tip of the probe so that the driving impedance is about 200Ω in the measurement band. Increased measurement accuracy of resonance frequency. The same effect was obtained by inserting a 100Ω resistor. The probe set is positioned so that the trimming window 41 is just over the open end of the resonance part to be adjusted. Positioning can be performed for each resonance part, and in this state, the shield plate 40 is connected to the ground potential. The position of the probe and the short-circuit pin can be reversed only for the last resonance part of the resonance part array.
[0085]
The predicted values of the resonance frequency and transmission null frequency of the high frequency filter shown in FIG. 35 were obtained by computer simulation.
[0086]
The method for adjusting the high frequency filter is basically executed according to the method shown in FIGS. First, as shown in FIGS. 39 and 40, an unadjusted high-frequency filter is set in the adjustment device, the probe set is placed on the first resonance unit 31, and the tightly coupled probe 11 is brought into contact with the resonance unit 32. . The resonance part 33 was short-circuited to the shield plate 40 by the short-circuit pin 52. The loosely coupled probe 62 is set to “selection valid”, and in this state, an electrically non-conductive rotating grindstone 91 is inserted from the trimming window 41, and the electrode 313 of the resonance unit 31 is trimmed until the transmission null frequency becomes a predetermined value. The input / output terminal 21 is left open. This trimming process corresponds to FIG.
[0087]
Next, as shown in FIGS. 41 and 42, the electrode 312 was trimmed until the resonance frequency reached the first predetermined value. This trimming process corresponds to FIG.
[0088]
Next, as shown in FIGS. 43 and 44, the input / output terminal 21 is grounded by the input / output short-circuit pin 51, and the electrode 314 facing the input / output terminal 21 is connected until the resonance frequency reaches the second predetermined value. Trimmed. This trimming process corresponds to FIG.
[0089]
Next, as shown in FIGS. 45 and 46, the short-circuit of the input / output terminal 21 by the short-circuit pin 71 is released, the probe set is set in the next resonance unit 32, the short-circuit pin 51 is resonated in the resonance unit 31, and The tightly coupled probe 11 is brought into contact with the part 33 and the shorting pin 52 is brought into contact with the resonating part 34 to trim the electrode 323. This trimming process corresponds to FIG.
[0090]
Hereinafter, the adjustment proceeds as described in FIGS. In the resonance part having no input / output terminal, adjustment to the second resonance frequency is omitted. In the last resonance unit 38, the arrangement direction of the probe and the ground short-circuit pin is reversed, and then the electrode 382 (see FIGS. 35 and 36) and the electrode 384 facing the input / output terminal 28 are trimmed.
[0091]
The input / output terminals 21, 24, and 28 and the input / output short-circuit pins 71 and 72 do not extend in the direction of the adjacent resonance part, and the path of the short-circuit current is in the vertical direction (parallel to the resonance part). If this condition is not satisfied, the coupling degree varies when the input / output terminals 21, 24, 28 and the input / output short-circuit pins 71, 72 are operated, causing an error.
The pass characteristics of the filter after adjustment showed very good agreement with the design prediction.
[0092]
C. Example 3
47 is a partial cross-sectional view showing another embodiment of the adjusting device according to the present invention, and FIG. 48 is a partially broken plan view of the adjusting device shown in FIG. The high frequency filter shown in FIGS. 35 and 36 is used. This high frequency filter was placed on a linear motion stage 100, moved linearly in the vertical direction Y (see FIG. 48), and the shield plate 40 on the open end was fixed.
[0093]
A trimming window 41 is opened in the shield plate 40, and tightly coupled probes 11 and 12 and ground short pins 51, 52, and 53 are arranged on both sides thereof. The grounding short-circuit pins 51 to 53 were led to the high frequency filter through holes (not shown) provided in the shield plate 40. The tightly coupled probes 11 and 12 and the grounding short-circuit pins 51 to 53 were driven in the vertical direction (in FIG. 47) by the air cylinders 81 to 85. The air cylinders 81 to 85 were driven according to a program set in advance by a computer. The loosely coupled probe 61 was fixed outside the trimming work area on the lower side of the trimming window 41. The two tightly coupled probes 11 and 12 were switched by a high frequency switch (not shown). One short-circuit pin 71 for short-circuiting the input / output terminals 21, 24, and 28 is provided, and this short-circuit pin 71 is also driven by computer programming. Although not shown in the figure, a circuit for detecting the presence or absence of the high-frequency filter by the conduction of the external conductor 20 is included.
[0094]
In the adjustment, as shown in FIGS. 49 and 50, the high-frequency filter is moved by the linear motion stage 100, the first resonance part 31 is placed under the trimming window 41, and the tightly coupled probe 12 is set to “valid”. The second resonance portion 32 is brought into contact. The grounding short-circuit pin 53 is brought into contact with the third resonating unit 33. Then, while monitoring the transmission null frequency from the tightly coupled probe 12 to the loosely coupled probe 61, an electrically non-conductive rotating grindstone 91 is inserted from the trimming window 41, and the coupling capacitance electrode is used until the transmitted null frequency reaches a predetermined value. 313 was trimmed.
[0095]
Next, as shown in FIGS. 51 and 52, the electrode 312 of the ground load capacitance was trimmed until the resonance frequency became the first predetermined value while the input / output terminal 21 was left open.
[0096]
Further, as shown in FIGS. 53 and 54, the input / output terminal 21 is grounded by the short-circuit pin 71, and in this state, the electrode 312 is trimmed until the resonance frequency becomes the second predetermined value.
[0097]
Next, after the adjustment of the first resonance unit 31 is completed, the tightly coupled probes 11 and 12 and the short-circuit pins 51 to 53 are raised, and the input / output terminal 21 and the short-circuit pin 71 are released. Then, as shown in FIGS. 55 and 56, the high frequency filter was moved by the linear motion stage 100, and the resonance part 32 was placed under the trimming window 41.
[0098]
The shorting pin 52 was applied to the adjusted resonance part 31, and the rotating grindstone 91 was applied to the resonance part 32 to be adjusted located under the trimming window 41. The tightly coupled probe 12 is brought into contact with the resonating part 33, and the shorting pin 53 is brought into contact with the next resonating part 34. In this state, trimming adjustment of the coupling amount and the resonance frequency similar to those described above was performed. Adjustments were made in the same manner. Adjustment to the second resonance frequency is omitted in the resonance part having no input / output terminal. In addition, when the resonance unit 37 immediately before the last one is an adjustment target, the short-circuit pin 53 is not used because there is no resonance unit corresponding to the short-circuit pin 53.
[0099]
This operation is repeated, and when the last resonating portion 38 comes under the trimming window 41, the short-circuit pin 51 in the reverse direction is brought into contact with the resonating portion 36, and the tightly coupled probe 11 is made effective to be brought into contact with the resonating portion 37. Similarly, the resonance frequency and input / output coupling were adjusted.
[0100]
The pass characteristics of the filter after adjustment showed very good agreement with the design prediction. In this embodiment, it is assumed that the arrangement intervals of the resonating parts are substantially equal. However, if the arrangement intervals of the resonating parts are not uniform, the positions of the shorting pins and the tightly coupled probes can be designed to be variable by a program. It is possible to cope with.
[0101]
D. Example 4
57 is a perspective view showing another embodiment of the high frequency filter to which the adjusting method according to the present invention is applied, and FIG. 58 is a plan view of the high frequency filter shown in FIG. The illustrated high frequency filter includes measurement electrodes 21 to 28 that are capacitively coupled to all the resonance units 31 to 38. Other configurations are the same as those of the high-frequency filter shown in FIGS.
[0102]
59 and 60 show an adjusting device suitable for adjusting the high-frequency filter shown in FIGS. 57 and 58. In the adjustment apparatus shown in the figure, the high frequency filter is placed on the linear motion stage 100 and linearly moved in the lateral direction, and the shield plate 40 on the open end is fixed. A trimming window 41 is opened in the shield plate 40, and grounding short pins 51, 52, 53 are provided. The grounding short-circuit pins 51 to 53 are moved up and down by air cylinders 81, 82, and 83 driven according to a computer program or the like. Loosely coupled probes 61 and 62 and terminal grounding short-circuit pins 71 and 72 are arranged at positions corresponding to the measurement electrodes of the high-frequency filter on both lower side surfaces of the trimming window 41. Further, the tightly coupled probes 11, 12, and 13 are arranged at positions corresponding to the measurement electrodes of the adjacent resonance parts. Both loosely coupled probes and tightly coupled probes can be switched with a high-frequency switch. The tips of the loosely coupled probes 61 and 62 are covered with insulators 611 and 621.
[0103]
The first resonance part 31 is placed under the trimming window 41, the loosely coupled probe 62 is connected to the measurement electrode 21 of the resonance part 31, the tightly coupled probe 12 is connected to the measurement electrode 22 of the resonance part 32, and the resonance part 33 is grounded. Shorting pins 53 were respectively applied. The trimming adjustment was performed in the same procedure as in Example 3 below. However, the probe enabled the side with the electrode, and did not enable the probe on the same side at the same time, and the electrode not used as the input / output terminal was short-circuited to the ground potential by the electrode terminal ground short-circuit pin when adjusting the resonance frequency.
[0104]
After the adjustment, as shown in FIG. 61, the short-circuit conductors 92, 93, 95, 96, and 97 are not shown for the electrodes 22, 23, 25, 26, and 27 that are not used as input / output terminals (92, 95, and 97 are not shown). Was printed and permanently shorted to the outer conductor. The short-circuit conductor was provided at a position not straddling the adjacent resonance part. The pass characteristics of the filter after short-circuit conductor printing showed a very good agreement with the design prediction. When a short-circuit conductor was printed at a position extending in the direction of the adjacent resonance part to create a current path in the lateral direction, the flatness of the pass band in the filter pass characteristics deteriorated and the stop band frequency was also shifted.
[0105]
E. Example 5
It is also possible to implement a configuration in which the insulating material at the tip of the loosely coupled probe of the apparatus of Example 4 is removed to enable tight coupling, and the SN ratio of measurement can be improved. This is because direct coupling between the probes is prevented, and the measurement electrode is grounded at the resonance frequency measurement stage, and unnecessary probes in contact with the electrodes are electrically disconnected. However, the unnecessary probe is actually pulled apart only when measuring the resonance frequency of the resonance part coupled to the input / output terminal. The result was the same as in Example 4, but the trimming speed was increased because the measurement of the transmitted null frequency was stabilized.
[0106]
F. Comparative example
For comparison, the first trial lot of the high frequency filter was subjected to the adjustment method of the present invention and the conventional adjustment method of adjusting while measuring the pass characteristics of the filter.
[0107]
In the method of the present invention, the trimming grinding amount of some of the resonance portions was slightly larger, but adjustment was possible without any particular problem, and the defect rate at the adjustment stage was 1% or less. On the other hand, in the sample that tried the conventional adjustment method, the deviation from the target characteristics was large, and there was a part where the magnitude relationship of the resonance frequency in the unadjusted state was reversed from the design, so it was judged that adjustment was impossible and lot out . It was only two weeks after a precise measurement of product shrinkage distribution and dielectric constant was performed, and this data was subjected to computer simulation. After the mold was corrected using the results, the prototype was completed again two weeks later. The defect rate at the adjustment stage of the conventional method for the second trial lot was 15%.
[0108]
In the embodiments, the dielectric filter has been described as an object, but the present system can be applied regardless of the lumped constant, the distributed constant, and the number of resonance stages as long as the configuration is similar to the equivalent circuit of FIG.
[0109]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(A) In a high-frequency filter having a structure in which a plurality of resonance parts are connected in cascade, without considering mutual interference, the resonance frequency of each resonance part, which is an individual adjustment element, the degree of coupling between resonance parts, the resonance part and input / output terminals It is possible to provide an adjustment method and an adjustment device capable of individually measuring and adjusting the degree of coupling with the.
(B) In a high-frequency filter having a structure in which a plurality of resonance parts are connected in cascade, an adjustment method capable of obtaining a high-frequency filter having a desired frequency characteristic only by adjusting each index to a predetermined value; An adjustment device can be provided.
(C) For this reason, skill is not required for the adjustment work, and the trouble of adjusting a plurality of locations little by little while driving to target characteristics while predicting mutual interference is also eliminated. Furthermore, since the probe is only loosely coupled to the resonance part to be actually adjusted, if the probe is arranged so that it does not overlap the work area for adjustment, the measurement work and the adjustment work can proceed simultaneously. It becomes possible. Thus, an adjustment method is provided in which the adjustment work is made efficient and automation is easy.
[0110]
As other effects, the adjustable range is greatly expanded as compared with the conventional adjustment method, so that it is possible to eliminate the labor of prior trial manufacture and correction of the manufacturing process and to improve the product yield.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a high frequency filter to which the present invention is applied.
FIG. 2 is a cross-sectional view of the high frequency filter shown in FIG.
3 is an equivalent circuit diagram of the high frequency filter shown in FIGS. 1 and 2. FIG.
4 is a more detailed equivalent circuit diagram of the high-frequency filter shown in FIGS. 1 and 2. FIG.
FIG. 5 is a diagram showing a measurement method according to the present invention.
6 is a diagram showing the measurement method shown in FIG. 5 in a further electrical form. FIG.
7 is a diagram showing the reflection characteristics of a tightly coupled probe obtained in the measurement state of FIGS. 5 and 6. FIG.
8 is a diagram showing transfer characteristics from a tightly coupled probe to a loosely coupled probe in the measurement state of FIGS. 5 and 6. FIG.
FIG. 9 is a diagram showing changes in the resonance frequency and the transmission null frequency when the coupling capacitance between the resonance parts is changed. .
FIG. 10 is a diagram showing changes in the resonance frequency and the transmission null frequency of the resonance unit when the ground load capacity is changed.
FIG. 11 is a diagram showing changes in the resonance frequency and transmission null frequency of another resonance unit when the ground load capacity is changed.
FIG. 12 is measurement data showing transfer characteristics before adjusting the ground load capacity.
FIG. 13 is measurement data showing transfer characteristics after adjusting the ground load capacity.
FIG. 14 is a diagram illustrating an adjustment method according to the present invention.
FIG. 15 is a diagram for explaining an adjustment step after that shown in FIG. 14;
FIG. 16 is a diagram for explaining an adjustment step after that shown in FIG. 15;
FIG. 17 is a diagram for explaining an adjustment step after that shown in FIG. 16;
FIG. 18 is a diagram for explaining an adjustment step after that shown in FIG. 17;
FIG. 19 is a diagram illustrating an adjustment step after that shown in FIG. 18;
FIG. 20 is a diagram for explaining an adjustment step after that shown in FIG. 19;
FIG. 21 is a diagram for explaining an adjustment step after that shown in FIG. 20;
FIG. 22 is a diagram showing transfer characteristics of a high-frequency filter obtained by applying the adjustment method according to the present invention.
FIG. 23 is a perspective view of a high-frequency filter used in Example 1 of the adjustment method according to the present invention.
24 is a cross-sectional view of the high frequency filter shown in FIG.
25 is a partial cross-sectional view showing a measuring device for the high frequency filter shown in FIGS. 23 and 24. FIG.
26 is a partial cross-sectional view showing an adjustment method using the measuring apparatus shown in FIG. 25. FIG.
FIG. 27 is a diagram showing the adjustment step shown in FIG. 26 as an electric circuit.
FIG. 28 is a diagram showing an adjustment step after the adjustment step shown in FIG. 27 as an electric circuit.
29 is a partial cross-sectional view showing an adjustment step after the adjustment step shown in FIGS. 26 to 28. FIG.
30 is a diagram showing the adjustment step shown in FIG. 29 as an electric circuit.
31 is a partial cross-sectional view showing an adjustment step after the adjustment step shown in FIGS. 29 and 30. FIG.
32 is a diagram showing the adjustment step shown in FIG. 31 as an electric circuit.
33 is a partial cross-sectional view showing an adjustment step after the adjustment step shown in FIGS. 31 and 32. FIG.
FIG. 34 is a diagram showing the adjustment step shown in FIG. 33 as an electric circuit.
FIG. 35 is a perspective view of a high frequency filter to which the present invention is applied.
36 is a cross-sectional view of the high frequency filter shown in FIG. 35. FIG.
37 is a diagram showing an adjustment device suitable for adjusting the high-frequency filter shown in FIGS. 35 and 36. FIG.
38 is a partial plan view of the adjusting device shown in FIG. 37. FIG.
FIG. 39 is a partial cross-sectional view showing steps of adjusting the high-frequency filter shown in FIGS. 35 and 36 using the adjustment device shown in FIGS. 37 and 38;
40 is a view of the adjustment device shown in FIG. 39 as viewed from the upper surface side.
41 is a partial cross-sectional view showing an adjustment step after the adjustment step of FIGS. 39 and 40. FIG.
42 is a view of the adjusting device shown in FIG. 41 as viewed from the upper surface side.
43 is a partial cross-sectional view showing an adjustment step after the adjustment step of FIGS. 41 and 42. FIG.
44 is a view of the adjustment device shown in FIG. 43 as viewed from the upper surface side.
45 is a partial cross-sectional view showing an adjustment step after the adjustment step of FIGS. 43 and 44. FIG.
46 is a view of the adjusting device shown in FIG. 45 as viewed from the upper surface side.
47 is a partial cross-sectional view showing another example of an adjusting device suitable for adjusting the high-frequency filter shown in FIGS. 35 and 36. FIG.
48 is a partial plan view of the adjusting device shown in FIG. 47. FIG.
49 is a diagram showing adjustment steps using the adjustment device shown in FIGS. 47 and 48. FIG.
50 is a partial plan view of the adjusting device shown in FIG. 49 as seen from the upper surface side.
51 is a partial cross-sectional view showing an adjustment step after the adjustment step shown in FIG. 49. FIG.
52 is a partial plan view of the adjusting device shown in FIG. 51 as viewed from the upper surface side.
53 is a partial cross-sectional view showing an adjustment step after the adjustment step shown in FIGS. 51 and 52. FIG.
54 is a partial plan view of the adjusting device shown in FIG. 53 as viewed from the upper surface side.
FIG. 55 is a partial cross-sectional view showing an adjustment step after the adjustment step shown in FIGS. 53 and 54;
56 is a partial plan view of the adjustment device shown in FIG. 55 as viewed from the upper surface side.
FIG. 57 is a perspective view showing another example of a high-frequency filter to which the present invention is applied.
58 is a plan view of the high frequency filter shown in FIG. 57. FIG.
59 is a partial cross-sectional view of an adjusting device suitable for adjusting the high frequency filter shown in FIG. 58. FIG.
60 is a plan view of the adjusting device shown in FIG. 59 as viewed from the upper surface side.
61 is a perspective view showing a high-frequency filter obtained by adjusting the high-frequency filter shown in FIGS. 57 and 58 with the adjusting device shown in FIGS. 59 and 60 and then providing a short-circuit conductor. FIG. .
[Explanation of symbols]
10 Dielectric ceramic
11 Tightly coupled probes
21, 22 I / O terminals
31-38 Resonance part
40 Shield plate
41 Trimming window
51-53 Shorting pin
61-62 Loosely coupled probe
71, 72 I / O short-circuit pin
C12, C23, C34 coupling capacity
Cin, Cout I / O coupling capacity
C01, C02, C03, C04 Ground load capacity

Claims (10)

A method for adjusting a high-frequency filter in which two or more resonance parts are connected in cascade,
Adjusting the coupling capacitance between two selected adjacent resonators;
After the step, adjusting the resonance frequency of each resonance unit,
Furthermore,
After adjusting the amount of coupling between the first resonance unit connected to the input terminal and its adjacent resonance unit, the step of adjusting the resonance frequency of the first resonance unit with the input terminal opened or not mounted When,
Next, the input terminal is coupled to the first resonance unit in a state where the input terminal is short-circuited to the ground equivalent potential at a high frequency, and in this state, the coupling amount between the input terminal and the first resonance unit is adjusted. Including steps,
Adjustment method of the high frequency filter. A method for adjusting a high-frequency filter in which two or more resonance parts are connected in cascade,
Adjusting the coupling capacitance between two selected adjacent resonators;
After the step, adjusting the resonance frequency of each resonance unit,
Furthermore,
After adjusting the amount of coupling between the last resonance part connected to the output terminal and its adjacent resonance part, the output terminal is opened or not attached, and the resonance frequency of the last resonance part is adjusted. And steps to
Next, in a state where the output terminal is short-circuited to the ground equivalent potential in terms of high frequency, the output terminal is coupled to the last resonance unit, and in this state, the coupling amount between the output terminal and the last resonance unit is adjusted. Including steps,
Adjustment method of the high frequency filter. A method for adjusting a high-frequency filter in which two or more resonance parts are connected in cascade,
Adjusting the coupling capacitance between two selected adjacent resonators;
After the step, adjusting the resonance frequency of each resonance unit,
Furthermore,
The method for preparing a high-frequency filter includes a step of obtaining an adjustment index, wherein the step includes coupling a high-frequency probe to each of two adjacently coupled resonance parts, and measuring a transmission null frequency between the two high-frequency probes. And this as the adjustment index,
Adjustment method of the high frequency filter. A method for adjusting a high-frequency filter according to claim 3,
The first resonance part for which the resonance frequency is to be obtained is substantially in a no-load state, a high-frequency probe is tightly coupled to the second resonance part that is adjacently coupled to the first resonance part, and signal reflection characteristics of the high-frequency probe Including a step of obtaining a resonance frequency from
High-frequency filter adjustment device. A method for adjusting a high-frequency filter according to claim 4,
One of the two high-frequency probes is loosely coupled to the resonance unit or electrically disconnected.
Adjustment method of the high frequency filter. An adjusting device used for adjusting a high frequency filter in which two or more resonance parts are connected in cascade,
Means for adjusting the coupling capacitance between two selected adjacent resonators;
Means for adjusting the resonance frequency of each resonance part after adjusting the coupling capacitance,
Furthermore,
After adjusting the amount of coupling between the first resonance unit connected to the input terminal and the adjacent resonance unit, the input terminal is opened or not mounted, and the resonance frequency of the first resonance unit is adjusted. Means,
The input terminal is coupled to the first resonance unit in a state where the input terminal is short-circuited to a ground equivalent potential at a high frequency, and in this state, means for adjusting a coupling amount between the input terminal and the first resonance unit is provided. Including,
Adjustment device. An adjusting device used for adjusting a high frequency filter in which two or more resonance parts are connected in cascade,
Means for adjusting the coupling capacitance between two selected adjacent resonators;
Means for adjusting the resonance frequency of each resonance part after adjusting the coupling capacitance,
Furthermore,
After adjusting the amount of coupling between the last resonance unit connected to the output terminal and its adjacent resonance unit, the output terminal is opened or not mounted, and the resonance frequency of the last resonance unit is adjusted. Means,
The output terminal is coupled to the last resonance unit in a state where the output terminal is short-circuited to the ground equivalent potential at a high frequency, and in this state, means for adjusting a coupling amount between the output terminal and the last resonance unit is provided. Including,
Adjustment device. An adjusting device used for adjusting a high frequency filter in which two or more resonance parts are connected in cascade,
Means for adjusting the coupling capacitance between two selected adjacent resonators;
Means for adjusting the resonance frequency of each resonance part after adjusting the coupling capacitance,
Furthermore,
The adjusting device includes at least two high-frequency probes, and couples the high-frequency probe to each of two adjacently coupled resonating units, measures a transmission null frequency between the two high-frequency probes, and adjusts this As an indicator,
Adjustment device. The adjustment device according to claim 8, comprising:
The first resonance part for which the resonance frequency is to be obtained is substantially in a no-load state, a high-frequency probe is tightly coupled to the second resonance part that is adjacently coupled to the first resonance part, and signal reflection characteristics of the high-frequency probe Including means for determining more resonant frequency,
Adjustment device. The adjustment device according to claim 9, comprising:
One of the two high-frequency probes has a structure that is loosely coupled to the resonance part or electrically detachable.
Adjustment device.

Images