JPH05114828A - Surface acoustic wave device and communication device using the same - Google Patents

Abstract

PURPOSE:To reduce the size of the whole system and to eliminate the depen dency of peripheral circuits of the surface acoustic wave device such as inductors and capacitors on the system side by putting the peripheral circuits in the same package by utilizing the gap up to the top plate of the package. CONSTITUTION:In the example shown in a figure, four kinds of inductance are realized by a plane element substrate 102 and a plane element electrode 104, superposed on a surface acoustic wave device substrate 103, and put in the same package. Plane elements are high in precision, so no element is added for adjustment. Even when an adjustment, etc., needs to be made because of variance in the characteristics of the surface acoustic wave device which requires the four kinds of inductance as an electric phase shifter, the plane element inductors themselves can finely be adjusted in inductance at the wiring position at the time of the connections, so a countermeasure can be taken without increasing the number of components. Adjusting operation regarding an electric phase is therefore facilitated. Consequently, the dependency of the surface acoustic wave device upon the system decreases and the size is reducible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface acoustic wave device suitable for miniaturization and high density, and a communication device using the same.

[0002]

2. Description of the Related Art A surface acoustic wave device is used in combination with a matching element, an LC filter, or the like when it is actually used, or when the surface acoustic wave element uses a unidirectional electrode, a phase shift is performed. In many cases, an inductor or a capacitor is used in combination as a container.

The performance of the matching element of the surface acoustic wave device or the inductors and capacitors used in the electrical phase shifter has a great influence on the frequency characteristics of the entire device. Particularly in the case of the low-loss surface acoustic wave device, for example, TTE. Ripple due to (triple transit echo) is partly due to insufficient precision of the values of the above elements used for the matching element and the electric phase shifter.
When constructing an electrical phase shifter for use as a unidirectional electrode of a surface acoustic wave element, sufficient unidirectionality can be obtained unless the error in the values of the elements constituting it is within about 5%. Ripple occurs in the used band due to TTE caused by insufficient unidirectionality. Also in the case of matching elements, if the error of the elements that compose it is large,
The effect of suppressing TTE and the effect of improving the loss of the surface acoustic wave device are both small. However, conventional coils and capacitors, or chip-type inductors and capacitors that have been commercially available in the past, generally have a large error in the accuracy of their values, and the value of 10 to 2
The actual situation is that it is about 0%.

When a circuit that requires a desired performance is formed by using such a component having a relatively large error in the nominal value, a plurality of elements are used, a variable element is used, or a planar element is formed on a substrate. Measures were taken such as using an element with a small error (hereinafter referred to as a planar element) that was realized in. A conventional surface acoustic wave device using a combination of planar elements is provided, for example, in Japanese Patent Application Laid-Open No. 54-43443 on the side of a piezoelectric substrate of a surface acoustic wave device using a group type unidirectional electrode. A technique of inserting a phase shifter composed of an air-core inductor held on an insulating substrate is described in the third embodiment.
This is disclosed by FIG. This is to avoid the influence of environmental temperature change on the inductance value by using an air-core inductor.

[0005]

As described above, in the past,
When configuring a peripheral circuit used in combination with the surface acoustic wave device, such as an electric phase shifter, a matching element, an LC filter,
Since the values of the elements for L, C, and R that compose these circuits are not always accurate, it is necessary to take measures such as using a plurality of elements in combination, using a variable element, or using a planar element. Had to be forced.

However, when a plurality of elements are used, the peripheral circuit of the surface acoustic wave device becomes complicated. If these elements are mounted on the same substrate as the surface acoustic wave device, the chip size becomes large and the cost becomes high. In addition, when the variable type element is used, the volume of the variable type element itself is large, and even when the planar element is used, it is configured on the same substrate as the surface acoustic wave device, or is configured on the same plane for different types of substrates. At this time, there is a problem that miniaturization is very difficult because the area occupied by the substrate becomes large and the substrate becomes large in order to obtain a value required as an element.

The present invention solves the above-mentioned conventional problems and eliminates the complexity of the element structure caused by insufficient precision of the values of inductors, capacitors, etc. while maintaining the performance as a whole or better than before. An object of the present invention is to provide a surface acoustic wave device which is compact and has a high density, and which does not rely on a peripheral circuit for the system side utilizing the surface acoustic wave device.

[0008]

In order to achieve the above object, the present invention is constituted by at least one element selected from an inductor, a capacitor and a resistor and is used by being electrically connected to a surface acoustic wave device. At least a part of the circuit is formed on the surface of the above-mentioned surface acoustic wave device by superimposing one or more substrates, each of which is formed of a highly precise element such as an inductor, a capacitor, and a resistor, which is formed in a plane. Decided to store them in the same package. Since the value error of the planar element is usually within about 5%, the circuit constructed by using the element is sufficiently practical. Although a planarly formed spiral metal pattern is used for the inductor, the present invention has a utilization target of about 100 MHz or more, and thus such a configuration is sufficient. Also, in most cases, the comb-teeth-shaped electrodes arranged opposite to each other are useful for the capacitor. As a circuit to be stored in the same package, a matching circuit for connecting the surface acoustic wave device in the package to another circuit outside the package, an electrical circuit for unidirectional electrodes of the surface acoustic wave device. It is practically convenient if a phase shifter, an LC filter or the like is selected. Since the piezoelectric substrate for the surface acoustic wave element is expensive, in practice L, C,
It is smaller in almost all cases than the substrate on which R is formed. When a small surface acoustic wave device substrate is overlaid on a relatively large substrate having L, C, and R formed in a plane, when wiring between terminals, especially in the case of an electrical phase shifter, etc. , Convenient. In addition, as described above, since the substrate of the surface acoustic wave device generally has a smaller area than the substrate in which L, C, and R are formed in a plane, a plurality of surface acoustic wave device substrates and their peripheral circuit substrates are formed. Can be stored in the same package, which can be very convenient. Further, the substrate on which L, C, and R are formed on a plane need not necessarily be a substrate having rigidity, and a flexible film substrate can be used to effectively utilize the internal volume of the package. However, as in the case of so-called TAB, there is no particular preference for a standard size film having holes on both sides. In addition, recently, when mounting the elements on the printed circuit board, a surface mount type element that requires only one side work is preferred, but a surface mount type package is used as the package used in the present invention. Of course, it doesn't matter.

[0009]

Conventionally, when the surface acoustic wave device is stored in a package, there is usually a gap of about 1 to 10 mm between the surface acoustic wave device and the top plate of the package. According to the present invention, since the peripheral circuit of the surface acoustic wave device can be incorporated in the same package by utilizing this gap, the peripheral circuit for using the surface acoustic wave device can be used as a system side using the surface acoustic wave device. It is much less necessary to prepare and install, and it is possible to achieve compactness and high density. Therefore, it is extremely effective for downsizing a communication device using the surface acoustic wave device as a filter or the like.

[0010]

1 (a) is a schematic side sectional view of a first embodiment of the present invention, and FIG. 1 (b) is a schematic top view of the same embodiment with the package removed. Reference numeral 101 is a printed circuit board, and 107 is a printed circuit board electrode formed on the printed circuit board 101. Reference numeral 102 denotes a planar element substrate on which an inductance element or a capacitance element incorporated in the same package as the surface acoustic wave device according to the present invention is formed, 104
Is a planar element electrode formed on the planar element substrate 102, 1
Reference numeral 03 is a surface acoustic wave device substrate, and reference numeral 106 is a surface acoustic wave device substrate electrode formed on the surface acoustic wave device substrate 103. Further, 105 is a package electrode, 110 is a package, 113 is a package pedestal, 108 is a metal wire, 109
Is an adhesive for fixing the substrates to each other or the substrate and the package pedestal, 111 is a solder, and 112 is a package terminal pin. The surface acoustic wave device of this embodiment has unidirectional electrodes and requires a total of four types of inductance as an electrical phase shifter. In this embodiment, the four types of inductances are realized by the planar element substrate 102 and the planar element electrode 104, and they are superposed on the surface acoustic wave device substrate 102 and stored in one package.

FIG. 2 is a schematic sectional view of a conventional surface acoustic wave device having the same performance as that of the first embodiment.
Reference numeral 1 is the electric phase shifter 102 and the planar element substrate 104.
Is an element (inductor or capacitor) corresponding to
Reference numeral 202 represents a terminal of the element 201. The surface acoustic wave device substrate 103 used in this conventional example is the same as that used in the first embodiment of the present invention. Therefore, four kinds of inductors are required as the electrical phase shifter of the unidirectional electrode. ,
These four inductors are constituted by variable coils that can be finely adjusted, and are mounted outside the package.

In the first embodiment, four kinds of inductances are realized by one planar element substrate 102 and its electrode 104, but there is no element added for adjustment because of the high precision of the planar element. In addition, even if adjustment due to variations in the characteristics of the surface acoustic wave device is necessary, since the inductance can be finely adjusted at the planar element inductor itself and the wiring position at the time of connection, it is possible to deal with it without increasing the number of parts. You can Therefore, the adjustment regarding the electrical phase can be simplified. Further, comparing the above-described conventional example with the first embodiment, the surface acoustic wave device of the first embodiment stores the element 201 mounted outside in the conventional surface acoustic wave device inside the package. Since it is not necessary to attach an electric phase shifter required for performing the function of the wave device to the outside of the package, the surface acoustic wave device is less dependent on the system. Further, since the element 201 is realized as a planar element and is housed inside the package, miniaturization is achieved. Since the surface acoustic wave device substrate 103 has a high insulating property, there is almost no influence of the electromagnetic field of the surface acoustic wave device due to the planar element, so that the surface acoustic wave device is placed on the planar element substrate 102 as in the first embodiment. Even with the structure in which the substrates 103 are stacked, the characteristics of the surface acoustic wave device are not deteriorated.

Further, the surface acoustic wave device shown in FIGS. 3 and 4 of JP-A-54-43443 can be miniaturized by applying the method of the present invention to form a hierarchical structure. It is the same as the conventional example shown in FIG. 2 can be miniaturized by the present invention as in the first embodiment shown in FIG.

FIG. 3 (a) is a schematic side sectional view of a third embodiment of the present invention, and FIG. 3 (b) is a schematic top view with the package removed. In the figure, 301 and 302 are planar element substrates incorporated in the same package as the surface acoustic wave device according to the present invention, and 303 and 304 are planar element substrate electrodes. The surface acoustic wave device used in this embodiment is the first 103 is the same as in the case of the embodiment. Therefore, four kinds of inductance are required as an electric phase shifter of a unidirectional electrode. On the other hand, a matching element is usually required for connecting the surface acoustic wave device and its external circuit. In this embodiment, four types of inductors necessary for an electric phase shifter are realized by one planar element substrate 302 and its electrode 304 and used for matching.
One kind of inductor is realized by another one of the planar element substrate 301 and its electrode 303, and it is stored in one package by being superposed on the surface acoustic wave device substrate. Also in the present embodiment, as in the first embodiment, the precision of the planar element is high, so that adjustment of the element is not necessary, the number of parts can be minimized, and the inductor which is conventionally mounted on the outside. Since the device is stored in the package, it is not necessary to add an element necessary for exhibiting the function of the device to the outside of the package, the dependency of the device on the system is reduced, and the miniaturization is achieved.

In the first and second embodiments, the electric phase shifter and the matching element for the unidirectional electrode are stored in the same package as the surface acoustic wave device, but the element to be stored can be realized by a planar element. If so, its type and use do not matter.

Further, in the above embodiment, only the inductor was used as the element realized by the planar element. However, as shown in FIGS. 4A and 4B, the electrode pattern 401 is used.
Since a capacitor and a resistance by the electrode pattern 402 can be realized by a planar element respectively, the type of the surface acoustic wave device can be stored in the same package as long as it is a planar element. is not. Further, the electrode patterns are not limited to those of the first and second embodiments and those shown in FIG. 4, and electrode patterns of other shapes may be used.

Furthermore, the number of planar element substrates to be superposed is not limited to one or two, and the number does not matter.

FIG. 5 is a block diagram showing the configuration of a third embodiment communication device of the present invention in which the surface acoustic wave device and the LC filter are housed in the same package and used. In the figure, 501 is an LC filter, and 502 is a surface acoustic wave device according to the present invention. In this embodiment, the LC filter 501 is connected in a plurality of stages in front of the surface acoustic wave device, but the characteristics as these filters do not have to be the same, and regarding the distinction between the front stage and the rear stage, and the number of stages thereof. There is no limit. By connecting an LC filter having an arbitrary characteristic that can be realized by a planar element to a surface acoustic wave device and storing the same in the same package, the surface acoustic wave device and the LC filter can be packaged in the package volume of the conventional surface acoustic wave device. And a multi-stage filter can be obtained, and the entire communication device can be downsized.

Although the number of the surface acoustic wave device substrates is one in each of the above embodiments, the number of substrates is not limited to one. FIG. 6 shows a schematic cross-sectional view of the surface acoustic wave device substrate portion of the fourth embodiment of the present invention. In this embodiment, a plurality of surface acoustic wave substrates are stacked and used. In the figure, 601 and 602 are both surface acoustic wave device substrates, and 603 is a surface acoustic wave device substrate 60.
1 is a surface acoustic wave device substrate electrode, 604 is a surface acoustic wave device substrate electrode formed on a surface acoustic wave device substrate 602, and 605 is a spacer for providing a gap between both surface acoustic wave device substrates. 606 is an adhesive. In this embodiment, the spacer 605 does not need to be separated from the adhesive 606, and the structure thereof does not matter as long as the substrate can be fixed and the space between the substrates can be maintained with one kind or plural kinds of materials. By adopting the structure of this embodiment, the surface acoustic wave device which has been conventionally stored in two packages can be stored in one package. The upper substrate does not have to be the surface acoustic wave device substrate, and may be a planar element substrate. Further, there is no limit to the number of substrates on the upper side. When the upper substrate is a planar element, it can be stored in one package, and in addition to confirming the characteristics of the surface acoustic wave device on the upper side, the planar element substrate or planar element to be used can be selected. It is possible to simplify adjustments such as possible.

FIG. 7 is a fifth embodiment of the present invention and is a schematic cross-sectional view of a surface acoustic wave device substrate and a planar element substrate housed in a single surface mount package. 701 in the figure
Is a printed board, 702 is a planar element substrate, 703 is a surface acoustic wave device substrate, 704 is a printed board electrode formed on the printed board 701, and 705 is a planar element board 702.
A planar element substrate electrode formed above, 706 a surface acoustic wave device substrate electrode formed on a surface acoustic wave device substrate 703, 707 a surface mount package top plate, 708 a surface mount package bottom plate, 709 a baking electrode, Reference numeral 710 is a metal wire, 711 is an adhesive, and 712 is solder. In this embodiment, regarding the surface acoustic wave device substrate and the planar element substrate which are housed in the surface mount package, the combinations shown in the above-mentioned first, second, third and fourth embodiments, and between the embodiments All combinations of can be applied.

FIG. 8 is a schematic cross-sectional view of a sixth embodiment of the present invention, in which the bottom substrate stored in the surface mount package is used as the bottom plate of the surface mount package. The board hierarchical structure has a higher density than that of the fifth embodiment, and the number of parts is reduced.

In FIG. 8, reference numeral 801 denotes a printed circuit board, and 8
Reference numeral 02 is a planar element substrate, 803 is a surface acoustic wave device substrate, 8
Reference numeral 04 is a printed circuit board electrode formed on the printed circuit board 801, 805 is a planar element substrate electrode formed on the planar element substrate 802, 806 is a surface acoustic wave device substrate electrode formed on the surface acoustic wave device substrate 803, Reference numeral 807 is a surface mount package top plate, 808 is a baking electrode, 809 is a metal wire, 810 is an adhesive, and 811 is solder.

As shown in the fifth and sixth embodiments, by using the surface mounting package and the technique of the present invention, the mounting density is greatly improved, and as a result, the device can be further downsized. In addition, the number of parts can be reduced, and
In the step of mounting the surface acoustic wave device, boring of the printed board is omitted, and the step is simplified.

FIG. 9 is a schematic sectional view of a surface acoustic wave device according to a seventh embodiment of the present invention, in which 901 is a surface acoustic wave device substrate, 902 is a film substrate, 903 is a surface acoustic wave device substrate electrode, and 904. Is a film substrate electrode, 905 is a spacer, and 906 is an insulating film. In this embodiment, a planar element is formed on a film substrate 902 with a film substrate electrode 904, an insulating film 906 is attached, and a spacer 90 is formed.
The surface acoustic wave device 901 and the electrode 903 thereof are pressure-bonded to each other via 5. As described in the fourth embodiment, the structure of the spacer 905 is not a problem as long as it can maintain the distance from the surface acoustic wave device substrate. Further, by forming the planar element electrode on the insulating film and disposing the insulating film on the surface acoustic wave device side, it is possible to prevent the influence of the planar element, and thus it is possible to further simplify the configuration as compared with the seventh embodiment. Further, the spacer 905 can be omitted depending on the characteristics of the film substrate 902 and the insulating film 906. According to the seventh embodiment, the connection between the surface acoustic wave device and the planar element substrate is ensured, the reliability is improved, and the package lid can be omitted.

FIG. 10 is a schematic sectional view of a planar element used in the eighth embodiment of the present invention. In the figure, 1001 is a film substrate, 1002 is a planar element substrate, 1003 is a film substrate electrode, and 1004 is a planar element substrate electrode. Is. When the inductor is formed of the planar element substrate, the Q value of the inductance may be low due to the insufficient film thickness of the substrate electrode. In order to make up for this, an electrode having the same pattern as that formed on the planar element substrate electrode is formed on the film substrate 1001 as a film substrate electrode 1003, and these are stuck together to compensate for the lack of film thickness. .. The method of this embodiment can be applied to all the first to seventh embodiments. Further, by adopting this configuration, it is possible to obtain the effect that the allowable amount of current increases.

FIG. 11 is a ninth embodiment of the present invention, and is a system block diagram when the apparatus of the second embodiment is used as an intermediate filter of a digital mobile radio apparatus. The digital mobile radio apparatus according to the present embodiment has a transmitter that modulates and transmits a transmission signal, an antenna, a receiver that receives a signal input from the antenna, and a clock unit. The transmission unit has a GMSK modulator 24, a mixer 25, an amplifier 26 and an RF filter 27, and has a transmission / reception changeover switch 3
RF filter 2 to which antenna 39 is connected via 8
8, an amplifier 29, an RF filter 30, a mixer 31, an amplifier 32, a filter device 33 of the present invention, an amplifier 34, a mixer 35, an amplifier 36, and an A / D converter 37. The clock unit has a system time base 40, an up converter PLL synthesizer 42, and a down converter PLL synthesizer 41. Since the surface acoustic wave device of the present invention is small, there is an effect that the entire system can be downsized.

[0027]

As described above, according to the present invention, the adjustment of the surface acoustic wave device, which has conventionally been complicated due to the accuracy of the element, can be simplified by using the plane element, and it can be installed as an external element. By storing the inductor and the capacitor that were previously installed together in the package that houses the surface acoustic wave device substrate, the same performance is maintained as before, but the package is compact and highly densified and is attached to the outside of the package. It is possible to provide a surface acoustic wave device that does not require any parts. Further, according to the present invention, it is possible to provide a communication device in which the entire system is downsized.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a surface acoustic wave device according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a surface acoustic wave device according to a conventional technique.

FIG. 3 is a diagram schematically showing a surface acoustic wave device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing an electrode pattern example of a planar element such as a capacitor and a resistor used in the present invention.

FIG. 5 is a block diagram showing a configuration of a communication device according to a third exemplary embodiment of the present invention.

FIG. 6 is a schematic sectional view of a substrate portion of a surface acoustic wave device according to a fourth embodiment of the present invention.

FIG. 7 is a schematic sectional view of a fifth embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view of a sixth embodiment with a higher density than that of the fifth embodiment.

FIG. 9 is a schematic sectional view of a surface acoustic wave device according to a seventh embodiment of the present invention using a film substrate.

FIG. 10 is a schematic cross-sectional view of a planar element portion of an eighth embodiment of the present invention in which a planar element substrate and a film substrate are used in an overlapping manner.

FIG. 11 is a system block diagram of a communication device using the surface acoustic wave device of the second embodiment as an intermediate filter of a digital mobile radio device.

[Explanation of symbols]

101 ... Printed circuit board, 102, 301, 302 ... Planar element substrate, 103, 601, 602, 703, 803 ... Surface acoustic wave device board, 902, 1001 ... Film board.

Claims (9)

[Claims] 1. At least a part of a circuit, which is composed of one or more kinds of elements among an inductor, a capacitor, and a resistor, and is electrically connected to a surface acoustic wave device, is planarly formed on a substrate. Elements such as inductors, capacitors and resistors are formed on one or more substrates, and one or more of such substrates are stacked on or under the substrate of the surface acoustic wave device and stored in the same package. A surface acoustic wave device characterized in that 2. An inductor formed planarly on a substrate,
The circuit configured by elements such as a capacitor and a resistor is used as a matching element for a surface acoustic wave device in the same package with respect to other circuits outside the package. Surface acoustic wave device. 3. A surface acoustic wave device having a unidirectional electrode, wherein a circuit constituted by elements such as an inductor, a capacitor, and a resistor formed in a plane on a substrate is provided with an electric circuit for the unidirectional electrode. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave device is used as a dynamic phase shifter. 4. An inductor formed planarly on a substrate housed in the same package as the substrate of the surface acoustic wave device,
2. The surface acoustic wave device according to claim 1, wherein a circuit composed of elements such as capacitors and resistors functions as an LC filter. 5. The surface acoustic wave device according to claim 1, wherein the upper substrate has a smaller area than the lower substrate. 6. A surface acoustic wave device in which two or more surface acoustic wave device substrates are housed in the same package. 7. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave device is housed in a surface mount type package. 8. The circuit according to claim 1, wherein a circuit composed of flat inductors, capacitors, resistors, and other elements is mounted on a thin flexible substrate. The surface acoustic wave device according to item 1. 9. A communication device using the surface acoustic wave device according to claim 1. Description: