JP4582311B2 - Signal transmission line, electronic component, and method for manufacturing signal transmission line - Google Patents

Description

  The present invention relates to a signal transmission line, an electronic component, and a method for manufacturing a signal transmission line. More specifically, the present invention relates to a transmission line such as a strip line or a microstrip line, an electronic component such as a resonator, a filter, a coupler, or a duplexer using the transmission line as a part of a circuit element, and a manufacturing method thereof.

  As a transmission line used in a high frequency circuit, a coaxial line in which a conductor having a circular cross section is disposed around a signal line through a dielectric, and a signal line are integrally formed in the dielectric, and at least both surfaces of the dielectric A strip line having a ground plane formed thereon and a microstrip line having a signal line formed on one side of a dielectric and a ground plane formed on the other side are well known.

  Among these, the coaxial line is used in a resonator that requires relatively long transmission and sharp resonance characteristics because of its low loss. On the other hand, the strip line and the microstrip line can be easily manufactured in combination with other circuit elements and can be thinned, so that they are often used for circuits inside devices.

However, although the strip line and the microstrip line have the above-mentioned advantages, the current is concentrated at both ends of the line, and there is a disadvantage that the transmission loss due to the conductor resistance is relatively large. For this reason, there is no problem with short transmission inside the device, but there is a problem that it is not suitable for applications where a slight loss is not allowed, such as an input stage of a receiver or a resonator that requires sharp resonance.
JP-A-5-283911

  An object of the present invention is to reduce a transmission loss due to a conductor resistance, and a signal transmission line that can be sufficiently used even in an application where a slight loss is not allowed, such as an input stage of a receiver or a resonator that requires sharp resonance, and An electronic component using the same, and a manufacturing method therefor are also provided.

  In order to solve the above-described problem, a transmission line according to the present invention includes a dielectric substrate, a ground conductor, and a signal line. The ground conductor is provided on the dielectric substrate. The signal line is formed of a conductor film, is provided on the dielectric substrate, extends in parallel with the ground conductor, and the conductor width changes stepwise at both ends in the width direction.

  As described above, in the transmission line according to the present invention, the ground conductor is provided on the dielectric base, and the signal line is also provided on the dielectric base and extends in parallel with the ground conductor. It functions as a microstrip line.

  In the strip line or the microstrip line, the signal line is composed of a conductor film, and the conductor width changes stepwise at both ends in the width direction, so that current concentration at both ends of the line is avoided and current concentration is avoided. It is possible to avoid an increase in the conductor resistance due to, and an increase in transmission loss associated therewith. For this reason, it is possible to obtain a signal transmission line that is useful in applications that cannot tolerate a slight loss, such as an input stage of a receiver or a resonator that requires sharp resonance.

  As one specific aspect, the signal line can be formed by laminating a plurality of conductor films. In this case, the conductor film of each layer is configured such that the conductor width changes stepwise at both ends in the width direction.

  Of the plurality of conductor films, the outermost conductor film may have the maximum width, and the other conductor film may be laminated on one surface side of the outermost conductor film. In this case, it is possible to adopt a structure in which the outermost conductor film has a surface exposed to the outside and the other conductor film is embedded in the dielectric substrate.

  As another aspect, among the plurality of conductor films, the intermediate conductor film may have the maximum width, and the other conductor films may be laminated on both surfaces of the intermediate conductor film. In this case, the plurality of conductor films are preferably embedded in the dielectric substrate.

  The transmission line according to the present invention can itself be used independently, and can also be used as a circuit element of a high-frequency electronic component. Specific examples of the electronic component include a resonator, a filter, and a coupler. The transmission line is used as an inductance component inside these electronic components. And LC circuit is comprised with the capacitor component normally equipped in these electronic components.

  The present invention further discloses a method for manufacturing the above-described signal transmission line. In this manufacturing method, first, a composite sheet is manufactured by fitting a conductive piece cut from a conductive sheet into a slit formed in advance in a dielectric green sheet. In this case, multiple types of composite sheets are prepared in which the widths of the slits and the conductive pieces are varied stepwise.

  Next, a plurality of the composite sheets described above are laminated and fired so that the conductor width due to the overlapping of the conductive pieces changes stepwise at both ends in the width direction. By including the steps described above, the signal transmission line according to the present invention can be easily obtained. This manufacturing method can also be applied to manufacturing resonators, filters, couplers, and the like.

The transmission line according to the present invention described above has the following effects.
(1) Transmission loss can be reduced by dispersing high-frequency current concentrated on both ends of the line.
(2) Therefore, the electronic device using the transmission line of the present invention has improved loss characteristics.
(3) When a resonator is formed using the signal transmission line of the present invention, the resonance characteristic becomes sharp, and it can be applied to an application where a larger resonator or a resonator using a coaxial line should be used.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

  FIG. 1 shows a cross-sectional view of a signal transmission line according to the present invention. The illustrated transmission line includes a dielectric substrate 1, a ground conductor 3, and a signal line 2. The dielectric substrate 1 can be a ceramic dielectric or an organic dielectric. The illustrated dielectric substrate 1 is formed into a plate shape or the like. The ground conductor 3 is provided on the dielectric substrate 1. In the figure, the grounding conductor 3 extends widely on one surface of the dielectric substrate 1.

  The signal line 2 is formed of a conductor film, is provided on the dielectric substrate 1, extends in parallel with the ground conductor 3, and the conductor width changes stepwise at both ends in the width direction. That is, when viewed in the film thickness direction, the conductor width changes stepwise like the widths W1, W2, and W3.

  As described above, in the transmission line according to the present invention, the ground conductor 3 is provided on the dielectric base 1, and the signal line 2 is also provided on the dielectric base 1, and extends in parallel with the ground conductor 3. Functions as a microstrip line.

  In the microstrip line, the signal line 2 is composed of a conductor film, and the conductor width changes stepwise at both ends in the width direction, such as the widths W1, W2, and W3. Concentration can be avoided, and increase in conductor resistance due to current concentration and accompanying increase in transmission loss can be avoided. For this reason, it is possible to obtain a signal transmission line that is useful in applications that cannot tolerate a slight loss, such as an input stage of a receiver or a resonator that requires sharp resonance.

  The illustrated signal line 2 is configured by laminating a plurality (three layers) of conductor films 21 to 23. The number of layers of the conductor films 21 to 23 is arbitrary. As for the conductor films 21 to 23 of each layer, the conductor width changes stepwise at both ends in the width direction as widths W1, W2, and W3 as the film thickness changes. In the illustrated embodiment, of the conductor films 21 to 23, the outermost conductor film 23 has the maximum width W3 (> W2> W1), and the other conductor films 21 and 22 are one surface of the outermost conductor film 23. Laminated on the side. The conductor films 21 to 23 are embedded in the dielectric substrate 1, and the outermost conductor film 23 has the same plane as the surface opposite to the surface on which the ground conductor 3 of the dielectric substrate 1 is provided. Configured and the surface is exposed to the outside.

  FIG. 2 is a sectional view showing another embodiment of the signal transmission line according to the present invention. In the figure, parts corresponding to the constituent parts appearing in FIG. In this embodiment, the outermost conductor film 23 is provided on the surface of the dielectric substrate 1 opposite to the surface on which the ground conductor 3 is provided, and the surface is exposed to the outside. Therefore, also in this embodiment, the ground conductor 3 is provided on the dielectric substrate 1 and the signal line 2 is also provided on the dielectric substrate 1 and extends in parallel with the ground conductor 3, so that it functions as a microstrip line. .

  FIG. 3 is a sectional view showing still another embodiment of the signal transmission line according to the present invention. In the figure, parts corresponding to the constituent parts appearing in FIG. In this embodiment, a plurality of (five layers) conductor films 21 to 25 are provided, and the intermediate conductor film 23 has the maximum width W3 (> W2> W1). The other conductor films 21, 22, 24 and 25 are laminated on both surfaces of the intermediate conductor film 23. These conductor films 21 to 25 are embedded in the dielectric substrate 1. Furthermore, ground conductors 31 and 32 are provided on both surfaces of the dielectric substrate 1 in the thickness direction. In this embodiment, the ground conductors 31 and 32 are provided on both surfaces in the thickness direction of the dielectric substrate 1, and the signal line 2 is provided so as to be buried substantially in the middle of the dielectric substrate 1 in the thickness direction. It functions as a strip line.

  In the case of the embodiment shown in FIGS. 2 and 3, the signal line 2 is formed of a conductor film, and the conductor width is stepwise like widths W1, W2, and W3 at both ends in the width direction. Therefore, current concentration at both ends of the line can be avoided, and increase in conductor resistance due to current concentration and accompanying increase in transmission loss can be avoided.

  Next, with reference to FIG.4 and FIG.5, the manufacturing method of the signal transmission line which concerns on this invention is demonstrated. In this manufacturing method, first, a slit formed in advance in a dielectric green sheet is formed as shown in steps A1 and A2 of FIG. Specifically, as shown in step A1, a dielectric paste is applied on the support so as to have a uniform thickness by a doctor blade method or the like, and dried to form the green sheet 101. The dielectric material to be used is not particularly limited as long as it is a general high-frequency dielectric having a high Q value and good temperature characteristics. However, in order to co-fire with the conductor forming the electrode, it is preferable that sintering is possible at the same temperature as the conductor material.

  Next, after passing through necessary processes such as a drying process, a slit S is formed in the green sheet 101 as shown in Step A2.

  On the other hand, as shown in Step B1, the conductive sheet 200 is formed by applying an electrode paste on a support and drying it in a process separate from Steps A1 and A2.

  The conductive material contained in the electrode paste is not particularly limited as long as it is a general high-frequency material, but preferably has a shrinkage behavior similar to that of the dielectric sheet. For example, if a dielectric that can be fired at about 900 ° C. is used, a metal having high conductivity such as Ag, Au, Cu, or Ag—Pd can be used.

  Next, as shown in step B <b> 2, the conductive piece 201 having the same shape as the slit S is cut out from the conductive sheet 200. Then, as shown in Step C, a conductive sheet 201 cut from the conductive sheet 200 is fitted into the slit S of the green sheet 101 obtained in Step A2, and a composite sheet is manufactured. In this case, multiple types of composite sheets are prepared in which the widths of the slits S and the conductive pieces 201 are changed stepwise.

  Next, as shown in FIG. 5, the composite widths 101 to 103 obtained through the above-described manufacturing steps are stepwise at the both ends in the width direction of the conductor width due to the overlapping of the conductive pieces 201 to 203. Laminated and fired in a changing relationship. The composite sheets 101 to 103 are laminated on one surface of the dielectric substrate 100 to which the ground conductor 300 is previously attached.

  According to the steps described above, the signal transmission line according to the present invention can be easily obtained. The construction method may not be a construction method using a green sheet, but may be printing or a multilayer substrate made of resin.

  The transmission line according to the present invention can be used independently, and can also be used as a circuit element of a high-frequency electronic component. Specific examples of the electronic component include a resonator, a filter, a coupler, and the like. The transmission line is used as an inductance component inside these electronic components. And LC circuit is comprised with the capacitor component normally equipped in these electronic components.

  6 is an exploded perspective view showing an example of the electronic component according to the present invention, FIG. 7 is an external perspective view of the electronic component shown in FIG. 6, and FIG. 8 is an equivalent electric circuit of the electronic component shown in FIGS. FIG. This electronic component is used as a filter. First, referring to FIG. 6, a dielectric layer 112 having signal transmission lines 211 and 212, a dielectric layer 113 having signal transmission lines 213 and 214, a signal transmission, on the dielectric layer 111 on which the ground conductor 31 is formed. A dielectric layer 114 having lines 215 and 216, a dielectric layer 115 having signal transmission lines 217 and 218, and a dielectric layer 116 having signal transmission lines 219 and 220 are sequentially laminated.

  The signal transmission lines 211 and 212, the signal transmission lines 213 and 214, the signal transmission lines 215 and 216, the signal transmission lines 217 and 218, and the signal transmission lines 219 and 220 constitute the inductor components L1 and L2 in FIG. The intermediate signal transmission lines 215 and 216 have the maximum width. The signal transmission lines 211 and 212, the signal transmission lines 213 and 214, the signal transmission lines 217 and 218, and the signal transmission lines 219 and 220 have a signal transmission line 215 such that the conductor width changes stepwise at both ends in the width direction. 216 are sequentially laminated on both surfaces of 216 to form a single signal transmission line. Therefore, current concentration at both ends of the line can be avoided, and increase in conductor resistance due to current concentration and accompanying increase in transmission loss can be avoided.

  On the dielectric layer 116, a dielectric layer 117 having an attenuation pole forming conductor 227, a dielectric layer 118 having capacitor electrodes 228 and 229, a dielectric layer 119 having capacitor electrodes 230 and 231 and a ground conductor 32 are provided. The dielectric layer 120 and further the protective layer 121 are sequentially stacked in this order.

  The signal transmission lines 219 and 220 provided in the dielectric layer 116 are electrically connected to the capacitor electrodes 230 and 231 provided in the dielectric layer 119 through via holes 221 to 226.

  One ends of the capacitor electrodes 228 and 229 are connected to the input / output terminals T1 and T2 (see FIGS. 7 and 8), respectively, and the ground conductors 31 and 32 are connected to the ground terminals GND1 and GND2. Thereby, a filter having the circuit configuration shown in FIG. 8 is obtained.

  However, the signal transmission line according to the present invention is not only applied to the filters shown in FIGS. 5 to 7, but can be widely applied to filters, couplers, resonators, duplexers, and the like having other configurations. It is.

  Next, specific examples of the present invention will be described.

  As a sample of the example, a chip type filter having the configuration shown in FIGS. 6 and 7 was produced by the sheet method shown in FIGS. 4 and 5. The shape of the obtained filter is 2.0 mm × 1.2 mm × 1.0 mm, and the dielectric used has a dielectric constant εr = 6. The dielectric used is a dielectric sheet with alumina, barium, and silica as the main components and a dielectric constant εr = 6. The dielectric is removed only from the portion corresponding to the transmission line, and the conductor sheet is removed on the trace. After that, a hole for a via hole was drilled as necessary in the same manner as a normal sheet, and a conductor was applied and laminated. Ag was used as the conductive material for forming the via hole, each conductor, and the electrode. Each of the green sheets forming the transmission line has a thickness of 40 μm.

  In the comparative example, the conductive pattern other than the transmission line is slightly changed in shape so that the band and the center frequency are the same, but the structure is the same as that of the example except for the transmission line portion.

  FIG. 9 shows the electrical characteristics of the examples and comparative examples. In FIG. 9, the horizontal axis represents frequency (GHz), and the vertical axis represents attenuation (dB). A curve L1 indicates the characteristics of the example, and a curve L2 indicates the characteristics of the comparative example.

  As is apparent from the comparison between the characteristics L1 and the characteristics L2, in the example, the insertion loss is improved by about 0.06 dB compared to the comparative example.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

It is sectional drawing of the signal transmission line which concerns on this invention. It is sectional drawing which shows another Example of the signal transmission line which concerns on this invention. It is sectional drawing which shows another Example of the signal transmission line which concerns on this invention. It is a figure explaining the manufacturing method of the signal transmission line concerning the present invention. It is a figure which shows the process after the process shown in FIG. It is a disassembled perspective view which shows an example of the electronic component which concerns on this invention. It is an external appearance perspective view of the electronic component shown in FIG. FIG. 8 is an equivalent electric circuit diagram of the electronic component shown in FIGS. 6 and 7. It is a figure which shows the frequency-insertion loss characteristic data of a filter.

Explanation of symbols

1 Dielectric substrate
2 Signal lines 21-23 Conductive film
3 Grounding conductor

Claims (3)

An electronic component including an inductance component and a capacitor component,
The inductance component includes a dielectric substrate and a signal line,
The signal line is configured by laminating a plurality of conductor films, provided on the dielectric substrate,
The plurality of conductor films, at both ends in the width direction, the conductor width changes stepwise as the film thickness changes,
The capacitor component has a capacitor electrode provided on a dielectric substrate, and constitutes an LC circuit together with an inductance component,
The dielectric substrate provided with the capacitor electrode is laminated on the dielectric substrate constituting the inductance component,
Further, one end of the signal line in the length direction is led out to an end face of the dielectric substrate and connected to a ground terminal, and the other end in the length direction is connected to the capacitor electrode by a via hole passing through the dielectric substrate. It is connected,
Electronic components. An electronic component including an inductance component and a capacitor component,
The inductance component includes a dielectric substrate and a signal line,
The signal line is configured by laminating a plurality of conductor films, provided on the dielectric substrate,
The plurality of conductor films, at both ends in the width direction, the conductor width changes stepwise as the film thickness changes,
Of the plurality of conductor films, the outermost conductor film has a maximum width when viewed in the stacking direction,
The capacitor component has a capacitor electrode provided on a dielectric substrate, and constitutes an LC circuit together with an inductance component,
The dielectric substrate provided with the capacitor electrode is laminated on the dielectric substrate constituting the inductance component,
Further, one end of the signal line in the length direction is led out to the end face of the dielectric substrate and connected to the ground terminal, and the other end in the length direction is connected to the capacitor electrode by a via hole passing through the dielectric substrate. It is connected,
Electronic components. An electronic component including an inductance component and a capacitor component,
The inductance component includes a dielectric substrate and a signal line,
The signal line is configured by laminating a plurality of conductor films, provided on the dielectric substrate,
The plurality of conductor films, at both ends in the width direction, the conductor width changes stepwise as the film thickness changes,
Among the plurality of conductor films, an intermediate conductor film has a maximum width when viewed in the stacking direction, and the other conductor films are stacked on both surfaces of the intermediate conductor film,
The capacitor component has a capacitor electrode provided on a dielectric substrate, and constitutes an LC circuit together with an inductance component,
The dielectric substrate provided with the capacitor electrode is laminated on the dielectric substrate constituting the inductance component,
Further, one end of the signal line in the length direction is led out to an end face of the dielectric substrate and connected to a ground terminal, and the other end in the length direction is connected to the capacitor electrode by a via hole passing through the dielectric substrate. It is connected,
Electronic components.

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