JP2006229213A - High-frequency device mounting board, communication equipment, and characteristic evaluation method for high-frequency device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-frequency device mounting board, communication equipment, and a characteristic evaluation method for the high-frequency device, in which an out-band attenuation characteristic in a highly miniaturized filter can be correctly measured/evaluated, each out-band attenuation characteristic and an isolation characteristic in a highly miniaturized duplexer can be correctly measured and evaluated with a transmission filter and a reception filter, and those characteristics can be excellently exhibited. <P>SOLUTION: On the surface of a circuit board whose rear face is covered by a rear face conductive layer 6, a terminal electrode 9 for mounting the high-frequency device 3 is formed, and a plurality of signal lines 2 for communicating between the high-frequency device 3 and an external circuit are formed. The terminal electrode 9 is arranged in the center section of the circuit board, and the signal lines 2 are radially extended from the terminal electrode 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a substrate on which a high-frequency device is mounted, and particularly suitable for mounting a high-frequency filter or a transmission / reception duplexer (hereinafter referred to as “duplexer”) which is a high-frequency device used in mobile communication equipment. The present invention relates to a mounting board.
The present invention also relates to a communication device on which the high-frequency device mounting substrate is mounted.
The present invention also relates to a method for evaluating characteristics of a high-frequency device mounted on the high-frequency device mounting substrate.

In recent years, high-frequency filters used in mobile communication devices such as mobile phones are small and light, have low loss in the passband, have a large attenuation outside the passband, and passband to passband. There is an increasing demand for a sharp change in characteristics toward the outside.
In addition, the duplexer that separates the signal on the transmission side frequency band (for example, relatively low frequency side) and the signal on the reception side frequency band (for example, relatively high frequency side) is also small and light, and is used for transmission within the duplexer. High frequency filters are required to have low loss in the transmission band and high attenuation in the reception band, and high frequency filters for reception are required to have low loss in the reception band and high attenuation in the transmission band. Further, in the duplexer, in order to prevent a transmission signal from leaking from the transmission terminal to the reception terminal, it is required that the isolation characteristic from the transmission terminal to the reception terminal is good. Further, as a duplexer, there is a demand for a smaller element in which a transmission high-frequency filter such as a low-frequency band side high-frequency filter and a reception high-frequency filter such as a high-frequency band side high-frequency filter are integrated.

Among them, conventionally, a duplexer using a dielectric has been used. However, the dielectric duplexer cannot be reduced in principle in the frequency band of the current communication standard.
Therefore, in recent years, attempts have been made to use a filter using a surface acoustic wave element for a duplexer. A surface acoustic wave element is usually configured by forming a plurality of excitation electrodes having comb-like electrodes on a piezoelectric substrate. The surface acoustic wave filter has been conventionally used as an interstage filter, but its power resistance is low when used as a duplexer. In recent years, however, this problem of power durability has been able to be solved by devising the electrode structure and electrode material of the excitation electrode, so that it is smaller than a dielectric duplexer and has good attenuation characteristics near the passband. Surface acoustic wave duplexers are beginning to appear.

  On the other hand, a technology for further downsizing the surface acoustic wave filter is also evolving. Conventionally, a surface acoustic wave device provided with an excitation electrode on a piezoelectric substrate is mounted in a recess of the package body, and the electrode pattern on the piezoelectric substrate and the terminal portion of the package are connected by wire bonding technology, and then the recess It is common to produce a surface acoustic wave filter by hermetically sealing with a cap or the like. In this case, it is possible to improve out-of-band attenuation characteristics and the like by effectively using the inductance component of the bonding wire.

In recent years, the CSP (Chip Size Package) technology has been actively used to further reduce the size of the package, and the surface acoustic wave device is flip-chip mounted on the circuit board, so that the conventional wire It has also been proposed to reduce the space and height required for bonding (see, for example, Patent Documents 1 and 2).
If a high-frequency device that does not satisfy the above requirements is used for communication equipment, unnecessary radio signals will be transmitted or received, and the quality of the received radio signals will be reduced, or interference to other radio communication equipment will occur. Or other problems may occur.

In addition, in order to evaluate the characteristics of high-frequency devices such as the above-mentioned high-frequency filters and duplexers, these high-frequency devices are mounted on an evaluation mounting board, and whether or not the desired characteristics are obtained is measured. Evaluation is done.
Since the measurement and evaluation must be performed accurately, the coaxial connector is usually used to connect the high-frequency device and the high-frequency device mounting board, or the high-frequency device mounting board and the coaxial cable connected to the measuring instrument. And the high-frequency device mounting substrate need to be firmly and securely joined using solder.

FIG. 22 shows a schematic perspective view of a general high-frequency device mounting substrate, a high-frequency device connected thereto, and a coaxial connector.
The high-frequency device mounting board is a circuit board 50 in which a plurality of insulator layers (not shown) are stacked and a ground conductor layer (not shown) is formed inside, and a necessary electric circuit is formed of a conductor. is there.

This electric circuit is for connecting a terminal electrode (not shown) for mounting the high-frequency device 41 to be evaluated, and a coaxial connector attached to connect a cable connected to the measuring instrument and the high-frequency device mounting substrate. The signal electrode 23 and the ground electrode 24, and the signal line 2 that connects the terminal electrode of the high-frequency device 41 and the signal electrode 23 are configured.
Further, a through hole 47 that penetrates the insulator layer of the circuit board 50 is provided, and a conductor layer is also provided on the inner surface of the through hole 47 so that the internal ground conductor layers are electrically connected to each other. The grounding effect may be increased by decreasing the height.

The coaxial connector usually includes a central conductor 44 for transmitting a signal, an outer peripheral conductor 45 surrounding and grounding the central conductor 44, and an insulating member for insulating them. The central conductor 44 is connected to the signal electrode 23 of the high-frequency device mounting substrate. In order to be able to do so, a shape protruding from the insulating member and having a thickness matching the width of the signal electrode 23 is used.
In order to assemble each member as shown in FIG. 22, first, cream solder is applied to the terminal electrode formed on the circuit board 50, and the high-frequency device 41 having the electrode provided at a position corresponding to the terminal electrode is formed thereon. After the high-frequency device mounting substrate and the high-frequency device 41 are connected by mounting and reflowing, the signal electrode 23 and the ground electrode 24, and the central conductor 44 and the outer peripheral conductor 45 of the coaxial connector are respectively connected to the thread solder and the soldering iron. Connect with solder.

Then, the coaxial connector is connected to the coaxial cable connected to the measuring instrument, and the characteristics of the high frequency device 41 are measured.
In order to remove the coaxial connector from the high-frequency device mounting substrate, it is necessary to heat the high-frequency device mounting substrate to a temperature at which the solder melts (200 ° C. to 300 ° C.) and to remove the high-frequency device 41 with tweezers or the like.
Japanese National Publication No.11-510666 Special Table 2002-504773

  At present, as a duplexer using a surface acoustic wave element, there is a smaller surface acoustic wave device in which a transmission filter, for example, a low frequency band side filter and a reception filter, for example, a high frequency band side filter are integrated. It is requested. In addition to a low insertion loss as a filter, higher attenuation characteristics are required for out-of-band attenuation characteristics. Furthermore, high isolation characteristics are required to prevent the transmission signal from leaking from the transmission terminal to the reception terminal.

Here, when the out-of-band attenuation characteristics of the transmission filter and the reception filter are deteriorated, an unnecessary wireless signal is transmitted or received, and the quality of the received wireless signal is reduced, Problems such as interference with other wireless communication devices may occur.
Therefore, in order to evaluate the characteristics of high-frequency devices such as surface acoustic wave filters and duplexers as described above, out-of-band attenuation characteristics and isolation characteristics in circuit boards that are actually used in mobile phones or the like equipped with such high-frequency devices. Therefore, these high frequency devices are mounted on a mounting substrate for evaluation, and it is measured and evaluated whether or not desired characteristics are obtained. The high-frequency device mounting substrate for that purpose is required not to affect the measurement / evaluation of desired characteristics so that the measurement / evaluation cannot be correctly performed due to the mounting substrate.

  In response to the above requirements, when a conventional relatively large surface acoustic wave device is mounted on a high-frequency device mounting substrate, the terminals of the device to be evaluated are sufficiently separated from each other. Components caused by the mounting board did not become a problem, but when a recent highly downsized surface acoustic wave device is mounted on a conventional high-frequency device mounting board, the signal lines on the mounting board are reduced in size. Measurements are performed due to unnecessary electromagnetic coupling between the signal lines due to the close proximity of the surface wave device size, resulting in degradation of out-of-band attenuation and isolation characteristics. The problem of being done has arisen.

  The present invention has been devised in view of the problems in the prior art as described above, and its purpose is to accurately measure and evaluate the out-of-band attenuation characteristics of a highly miniaturized filter. In a miniaturized duplexer, the transmission filter and the reception filter can accurately measure and evaluate the out-of-band attenuation characteristics and the isolation characteristics accurately, and also exhibit these characteristics well. An object of the present invention is to provide a high-frequency device mounting substrate that can be used.

Also, in recent years, high-frequency devices have been reduced in size and weight, and as a result, the heat capacity of the device itself is reduced, and there is a problem that heat resistance deteriorates. When it is necessary to attach and detach, there is a demand to complete the attachment and detachment with a heating time shorter than the conventional work time.
Furthermore, not only when performing measurement / evaluation as described above, but also when mounting a high-frequency device mounting board in a communication device such as a base station or a terminal and actually operating it, the high-frequency device mounting board and other circuit components It is required that the coaxial connector for connecting the connector and the high-frequency device mounting substrate be firmly connected using solder. If the connection is weak, the certainty of conductivity is lost, and the reliability of the operation of the high-frequency device is lowered.

Accordingly, another object of the present invention is to provide a high-frequency device mounting substrate that can ensure a strong connection with a coaxial connector and that can be easily removed when removed.
Still another object of the present invention is to provide a method for evaluating the characteristics of a high-frequency device that can evaluate the characteristics of the high-frequency device mounted on the high-frequency device mounting substrate with high reliability.

  The high-frequency device mounting substrate of the present invention includes a circuit board having a conductor layer on the back surface or inside of an insulator layer, a plurality of terminal electrodes installed on the surface of the circuit board for mounting a high-frequency device, and the circuit A plurality of signal lines installed on a substrate and connected to the terminal electrodes, the signal lines extending radially from the terminal electrodes, and a straight line virtually extending any one signal line from the terminal electrodes; The straight line obtained by virtually extending another arbitrary signal line from the terminal electrode does not constitute the same straight line.

The two extension lines may intersect at one point or may be parallel to each other.
The terminal electrode may be disposed at an arbitrary position on the circuit board. For example, you may arrange | position in the center part.
According to this high-frequency device mounting substrate, the signal lines extending radially from the terminal electrodes can shorten the adjacent portions of the signal lines between adjacent signal lines. Can be reduced. Further, since the directions of the signal lines are deviated, there is an advantage that a signal that has propagated linearly through the signal line is difficult to propagate to other signal lines. In general, in a quasi-TEM wave that is a transmission mode of a microstrip line, when the extending directions of two signal lines constitute the same straight line, a signal is most easily propagated between the signal lines. In the case where the radially extending signal lines are not opposed to each other with the terminal electrode interposed therebetween, electromagnetic interference between the signal lines can be reduced, and unnecessary propagation can be suppressed.

Therefore, when the high frequency filter or duplexer is used as the high frequency device, the present invention can satisfactorily exhibit the out-of-band attenuation characteristics and the isolation characteristics.
A ground conductor layer is provided on both sides of the signal line on the surface of the circuit board, and a gap W between the signal line and the ground conductor layer is formed on the back surface or inside of the signal line and the insulator layer. It is preferable that it is larger than the space | interval t with the said conductor layer.

The space between the signal line and the ground conductor layer is half-filled with air and a dielectric with a higher dielectric constant than air, whereas the gap between the signal line and the conductor layer is a dielectric with a higher dielectric constant than air. be satisfied. For this reason, the electric field tends to concentrate between the signal line and the conductor layer.
Therefore, by making the distance between the signal line and the conductor layer narrower than the distance between the signal line and the ground conductor layer, the electromagnetic field generated around the signal line is reduced with the conductor layer on the back surface facing the signal line in particular. It can be confined in the insulating layer between.

Therefore, electromagnetic interference in the air between the signal lines installed on the surface of the mounting board can be reduced, and when a high frequency filter or duplexer is used as a high frequency device, their out-of-band attenuation and isolation characteristics are reduced. The influence on the measurement and the obstacle to the performance can be further improved.
When a plurality of through conductors that penetrate the circuit board and are electrically connected to the conductor layer formed on the back surface or inside of the insulator layer are formed, the through conductor and the back surface or internal conductor Since the ground conductor layers disposed on both sides of the signal line are electrically connected via the layers, a potential difference can be eliminated between the ground conductor layers. Therefore, since the ground potential of the ground conductor layer on the surface of the circuit board can be stabilized and interference between signal lines through the ground conductor layer can be reduced, when a high frequency filter or duplexer is used as a high frequency device. These out-of-band attenuation characteristics and isolation characteristics can be measured and evaluated more satisfactorily, or the characteristics can be exhibited.

  In addition, when the high frequency device is a piezoelectric filter, the signal line extending from the input terminal and the output terminal of the piezoelectric filter is configured as described above, so that the influence on the out-of-band attenuation characteristic of the piezoelectric filter is affected. This can be improved compared to the device mounting board. Moreover, excellent out-of-band attenuation characteristics can be maintained even when a highly miniaturized piezoelectric filter is used.

  In addition, when the high frequency device is a duplexer using a piezoelectric filter, electromagnetic coupling between signal lines extending from the transmission terminal, the antenna terminal, and the reception terminal of the duplexer can be suppressed. In addition, it is possible to realize a mounting substrate that has excellent out-of-band attenuation characteristics in each of the transmission high-frequency filter and the reception high-frequency filter of the duplexer and that can obtain high isolation characteristics. Moreover, excellent out-of-band attenuation characteristics and isolation characteristics can be maintained even when a highly miniaturized duplexer is used.

Note that the piezoelectric filter mounted on the high-frequency device mounting substrate of the present invention and the duplexer using the same are so-called FBAR (Film) using bulk waves even if they are elements using surface acoustic waves. An element using a Balk Acoustic Resonator may be used. The effect of the present invention is effective for all miniaturized high frequency filters and duplexers.
The high-frequency device mounting substrate of the present invention is also suitable for configuring a circuit module such as a circuit substrate that is actually used in mobile communication devices or the like, or a module substrate for integrating and reducing the RF part of communication devices. Can be used for

Furthermore, as will be described later, the high-frequency device mounting substrate of the present invention can be suitably used for measurement and evaluation of high-frequency devices.
Next, the high-frequency device mounting substrate of the present invention may have the following configuration (hereinafter referred to as configuration A) in addition to the above configuration.
That is, a circuit board having a conductor layer on the back surface or inside of the insulator layer, a terminal electrode for mounting a high-frequency device installed on the surface of the circuit board, the terminal installed on the surface of the circuit board, and the terminal A signal line connected to an electrode, and disposed at a peripheral portion of the surface of the circuit board; a signal electrode connected to the signal line and connected to a central conductor of a coaxial connector; and disposed at a peripheral portion of the surface of the circuit board; A ground electrode for connecting the outer peripheral conductor of the coaxial connector using solder, and in the ground electrode, a through hole penetrating the circuit board is formed in a region to which the solder adheres, A conductor layer is deposited on the inner surface of the through hole.

According to this high-frequency device mounting substrate, when the outer peripheral conductor of the coaxial connector is attached using solder, the solder flows into the through hole. As a result, the outer peripheral conductor of the coaxial connector can be firmly joined to the ground electrode of the circuit board.
Further, the internal ground conductor layer is connected to the ground potential of the measuring instrument in a state where the parasitic inductance is smaller than in the case where the through hole 47 is provided in the portion of the circuit board 50 close to the high frequency device 41 as in the conventional FIG. Therefore, the characteristics of the high frequency device can be measured more accurately.

  The effect of attaching the coaxial connector in the high-frequency device mounting substrate of the present invention as described above to the high-frequency device mounting substrate is that the coaxial connector and the high-frequency device mounting substrate are temporarily connected, and the coaxial connector is removed after the measurement. Of course, this is also effective when connecting a so-called main board that requires a permanent connection and a connector that connects the main board and an external circuit.

Further, as will be described later, when removing the coaxial connector from the high-frequency device mounting substrate, it is effective when repair is necessary in the connection between the main board and the connector that require permanent connection.
The circuit board is a laminated board in which a plurality of insulator layers are laminated, an internal conductor layer is formed therein, and the conductor layer formed on the inner surface of the through hole is connected to the internal conductor layer. May be.

Further, a second ground electrode is formed at a portion corresponding to the ground electrode on the back surface of the circuit board, and the second ground electrode is interposed through the conductor layer formed on the inner surface of the through hole. It is preferable to be connected to the ground electrode.
In this structure, since the solder continuously exists through the through hole to the second ground electrode, the coaxial connector can be connected more firmly. At the same time, when soldering, the heat of the soldering iron quickly passes from the solder existing on one surface (for example, the front surface) to the solder existing on the other surface (for example, the back surface) through the solder in the through hole. Therefore, the solder on both sides can be melted at the same time, and the amount of solder on both sides is equalized through the through holes.

  Also, when removing the coaxial connector, the solder on both sides can be melted at the same time, so that the removal operation can be completed easily in a short time. Therefore, the mounted high frequency device can be removed without deteriorating its characteristics. Further, they can be reused without damaging the coaxial connector or the high-frequency device mounting substrate by heat.

In the case where a plurality of the through holes are arranged in a portion of the ground electrode along the outer periphery of the circuit board, the electrical connection of the outer peripheral conductor of the coaxial connector to be connected by solder-the conductor layer in the through hole-the inner layer conductor Since the target path can be made the shortest, the parasitic inductance caused by the conductor layer in the through hole can be made the smallest.
When the through hole is further arranged at a portion of the ground electrode opposite to the signal line from the outer periphery of the circuit board toward the central portion, the following effects are obtained.

  In conventional high-frequency device mounting boards, if the amount of solder is increased in order to achieve a strong joint when connecting the coaxial connector, the signal electrode and the ground electrode that are placed close to each other may be short-circuited via the solder. According to the high-frequency device mounting substrate of the present invention, when the through hole is further arranged from the outer periphery of the circuit board toward the central portion at a portion opposite to the signal line of the ground electrode, When soldering, the excessive solder with respect to the ground electrode on the front surface flows to the second ground electrode on the back surface through the further disposed through hole, so that the shape of the solder is slightly opposite to the signal line of the ground electrode. Become. For this reason, it is possible to make it difficult for the solder to be used to flow to the signal electrode side, so that it is possible to effectively prevent the signal electrode and the ground electrode from being short-circuited via the solder.

When the surface ground conductor layer formed along the signal line is connected to the surface of the circuit board to the ground electrode, the surface ground conductor layer is grounded with the smallest parasitic inductance. Since it can be connected to an electrode, the potential of the grounded electrode among the signal terminals of the high-frequency device can be made closer to the ground potential of the measuring instrument.
In the method for evaluating characteristics of a high-frequency device according to the present invention, the high-frequency device is mounted on a high-frequency device mounting substrate in which signal lines extend radially from the terminal electrodes, and a measurement wiring is connected to the high-frequency device mounting substrate. This is a method for inspecting characteristics of the high-frequency device mounted on a device mounting board. In this method, since the signal lines extend radially from the terminal electrodes of the high-frequency device mounting substrate, the electromagnetic coupling between the signal lines is reduced, and the characteristics of the high-frequency device can be accurately measured.

  In the method for evaluating the characteristics of the high-frequency device according to the present invention, when a high-frequency device mounting substrate having the configuration A is used, a coaxial connector is securely connected to the high-frequency device mounting substrate, and the characteristics evaluation of the high-frequency device is performed. In addition, it is possible to easily remove the high-frequency device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings described below, the same parts and the same parts are denoted by the same reference numerals.
1 and 2 show an example of the high-frequency device mounting substrate of the present invention. FIG. 1 is a plan view showing a state in which a duplexer 3 as a high frequency device is mounted on a high frequency device mounting substrate 1. FIG. 2 is a plan view showing only the high-frequency device mounting substrate 1 on which the duplexer 3 is not mounted.

The high-frequency device mounting substrate 1 is composed of a circuit board including an insulator layer 7. The duplexer 3 is mounted on the surface of the insulator layer 7. The duplexer 3 includes at least a transmission high-frequency filter and a reception high-frequency filter (both not shown).
A plurality of terminal electrodes 9 to be connected to the duplexer 3 are installed on the surface of the insulator layer 7 of the circuit board corresponding to the electrode arrangement of the duplexer 3.

A surface ground conductor layer 4 and a plurality of signal lines 2 a to 2 c (collectively referred to as “signal lines 2”) are provided on the surface of the insulator layer 7 of the circuit board.
Each signal line 2 is connected to a predetermined terminal electrode 9 and extends radially from the terminal electrode 9.
The surface ground conductor layer 4 is connected to another predetermined terminal electrode 9.
Thus, the terminal electrode 9 includes one connected to each signal line 2 and one connected to the surface ground conductor layer 4.

The back surface of the insulator layer 7 is covered with a back conductor layer 6 (see FIG. 3).
As shown in FIGS. 1 and 2, the ground conductor layers 4 are disposed on both sides of the signal lines 2 that extend radially. These surface ground conductor layers 4 are installed on both surfaces of the signal line 2 on the surface of the insulator layer 7 with gaps W provided. This gap W is made wider than the interval t (see FIG. 3) between the signal line 2 and the back conductor layer 6.

  A plurality of through conductors 5 are arranged along the side of the surface ground conductor layer 4 close to the signal line 2. These through conductors 5 are for connecting the surface ground conductor layer 4 and the back conductor layer 6 of the insulator layer 7. Such a through conductor 5 may be a so-called through-hole conductor in which a conductor is deposited on the inner wall of a through-hole provided in the insulator layer 7, or a so-called via conductor in which the inside of the through-hole is filled with a conductor. Good.

FIG. 3 is a cross-sectional view of the main part taken along the line AA ′ of FIG.
As shown in FIG. 3, the back conductor layer 6 of the insulator layer 7 is electrically connected to the surface ground conductor layer 4 on the surface of the insulator layer 7 by the through conductor 5. The back conductor layer 6 is grounded by being connected to the grounding outer conductor of the connector with solder at the connector mounting portion on the end face of the high-frequency device mounting substrate 1 for connecting the signal line 2 to an external measuring device or the like, As a result, the ground potential of the surface ground conductor layer 4 is stabilized.

In the embodiment shown in FIGS. 1 to 3, the terminal electrode 9 is arranged at the center of the insulator layer (circuit board) 7 as shown in FIG. 2, and the signal line 2 is radiated from the terminal electrode 9. Since the length of the adjacent portion between the signal lines 2 can be shortened, electromagnetic interference between the signal lines can be reduced.
In particular, as shown in FIGS. 1 and 2, the radially extending signal lines 2 are arranged with the terminal electrode 9 therebetween. That is, the terminal electrode 9 is disposed so as to terminate the radially extending signal line 2. At the same time, a straight line virtually extending one arbitrary signal line 2 from the terminal electrode 9 and a straight line virtually extending another arbitrary signal line 2 from the other terminal electrode 9 are: The same straight line is not configured.

For this reason, since the signal propagating linearly through the signal line is less likely to be coupled to other signal lines, it is possible to suppress electromagnetic interference between the signal lines, thereby providing excellent out-of-band attenuation characteristics and isolation. The characteristics can be maintained.
Further, although the surface ground conductor layer 4 is provided on both sides of the signal line 2, air and a dielectric (for example, glass epoxy resin; relative dielectric constant 4.7) are formed between the signal line 2 and the surface ground conductor layer 4. In contrast, the space between the signal line 2 and the back conductor layer 6 is all filled with a dielectric. For this reason, the electric field tends to concentrate between the signal line 2 and the back conductor layer 6.

In particular, when the gap W between the signal line 2 and the surface ground conductor layer 4 is made wider than the distance t between the signal line 2 and the back conductor layer 6, the concentration of the electric field becomes more remarkable.
Therefore, since it is possible to suppress the spread of the electromagnetic field distribution generated around the signal line, it is difficult for the signal to leak into the air and interfere with the adjacent signal line 2. Therefore, interference between adjacent signal lines 2 can be satisfactorily suppressed, and excellent out-of-band attenuation characteristics and isolation characteristics can be maintained.

  Specifically, an 800 MHz band duplexer 3 is arranged with a signal line 2 having a width of 0.13 mm on an insulator layer 7 having a thickness t = 0.1 mm, and a gap of W = 1 mm between the signal line 2 and the signal line 2. When the duplexer 3 is mounted on the high-frequency device mounting substrate 1 provided with the surface ground conductor layer 4 and the characteristics are evaluated, the isolation characteristic of the transmission band becomes −70 dB. When the ratio of the thickness t of the insulating layer 7 and the gap W between the signal line 2 and the surface ground conductor layer 4 is 1: 1, it becomes −60 dB. When these are compared, the isolation characteristic is improved by about 10 dB by setting the ratio of the thickness t of the insulator layer 7 to the gap W between the signal line 2 and the surface ground conductor layer 4 to 1:10.

  Further, since the plurality of through conductors 5 electrically connected to the back surface conductor layer 6 are connected to the ground conductor layer 4 disposed on both sides of the signal line 2, the front surface ground conductor layers 4 are connected to each other through the through conductors. 5 and the back conductor layer 6 are electrically connected. Therefore, the surface ground conductor layers 4 on both sides of the signal line 2 have the same potential, and a potential difference between the surface ground conductor layers 4 can be eliminated, and the ground potential of the surface ground conductor layer 4 can be stabilized. Therefore, interference between the signal lines 2 via the surface ground conductor layer 4 can be reduced, and the characteristics of the high-frequency device 3 can be improved.

Specifically, by arranging via conductors having a diameter of 0.3 mm as the through conductors 5 at intervals of 0.7 mm along the side of the surface ground conductor layer 4 on the signal line side, the via conductors 5 are more isolated than the case without the through conductors 5. About 5 dB.
According to the high-frequency device mounting substrate 1 as described above, when the high-frequency device 3 is a duplexer, it can be obtained without deteriorating out-of-band attenuation characteristics and isolation characteristics of the transmission high-frequency filter and the reception high-frequency filter of the duplexer 3. You can get the characteristics.

Therefore, when used as a high-frequency module, the function of the high-frequency device mounting substrate can be improved by exhibiting the characteristics of the high-frequency device such as the duplexer 3 as desired.
Further, when the high-frequency device 3 is a piezoelectric filter, the ground potential of the surface ground conductor layer 4 is stabilized, whereby interference between the signal lines 2 via the surface ground conductor layer 4 can be reduced. The attenuation characteristic can be maintained well.

The number of signal lines 2 and the installation angle are not limited to those shown in FIGS.
In FIG. 1 and FIG. 2, three signal lines 2 are arranged at an equal angle. However, for example, as shown in FIG. 4, four signal lines 2 may be arranged radially. The angle between the signal lines 2 is not necessarily equal.
In the case of FIG. 4, a straight line obtained by virtually extending one arbitrary signal line 2 from the terminal electrode 9 and a straight line obtained by virtually extending another arbitrary signal line 2 from the terminal electrode 9 Cross at one point.

Further, as shown in FIG. 5, the signal lines 2 may be arranged radially and in parallel. In this case, a straight line obtained by virtually extending any one signal line 2 from the terminal electrode 9 and a straight line obtained by virtually extending another arbitrary signal line 2 from the terminal electrode 9 are parallel to each other. It has become.
Even in the case of FIG. 4 and FIG. 5, similarly to the configuration of FIG. 1 and FIG. 2, the signal that has propagated linearly through the signal line becomes difficult to be coupled to other signal lines. Interference can be suppressed, whereby excellent out-of-band attenuation characteristics and isolation characteristics can be maintained.

FIG. 6 is a cross-sectional view of a principal part of another structural example of the high-frequency device mounting substrate of the present invention. As a comparative example, the structure of the high-frequency device mounting substrate is shown in FIG.
Since the planar shapes of these high-frequency device mounting substrates are the same as those in FIGS. 1 and 2, the plan views are omitted.
6 is a cross-sectional view of a main part cut along a line BB ′ in FIG. 1, and FIG. 7 is a cross-sectional view of a main part cut at the same position. In FIG. 6, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

In the embodiment example of the present invention shown in FIG. 6, the high-frequency device mounting substrate 1 'is a back conductor covering the back of the signal line 2 (not shown), the surface ground conductor layer 4, the insulator layer 7b, and the insulator layer 7b. The multilayer circuit board includes a layer 6b, an insulator layer 7a laminated on the insulator layer 7b with the back conductor layer 6b interposed therebetween, and a back conductor layer 6a covering the back surface of the insulator layer 7a.
As a numerical example, the insulator layer 7a has a thickness of 1 mm and the insulator layer 7b has a thickness of 0.1 mm. By providing the insulator layer 7a, the strength of the high-frequency device mounting substrate 1 'can be increased. it can. Furthermore, another circuit can be formed on the back conductor layer 6a.

If an insulating layer is further provided and the conductor layer has a multilayer structure, circuits can be further integrated. By this integration, a circuit board used for mobile communication equipment such as a mobile phone can be reduced in size.
As in FIG. 6, the high-frequency device mounting substrate 10 shown in FIG. 7 includes a ground conductor layer 14, an insulator layer 17 b, a conductor layer 16 b that covers the back surface of the insulator layer 17 b patterned in a predetermined pattern shape, and a conductor layer This is a multilayer circuit board comprising an insulating layer 17a laminated on an insulating layer 17b with 16b interposed therebetween, and a conductor layer 16a covering the back surface of the insulating layer 17a.

  In the high-frequency device mounting substrate of FIG. 7, when a conductor layer is provided in the region 18 immediately below the terminal electrode 19 on which the high-frequency device 3 such as a duplexer is mounted, parasitic capacitance is generated between the terminal electrode 19 and the conductor layer. If the parasitic capacitance is generated in this way, the characteristic impedance of the terminal electrode 19 part deviates from 50Ω, and signal reflection occurs and the characteristic deteriorates. Therefore, the conductor is connected to the region 18 immediately below the terminal electrode 19. The layer is not provided.

For this purpose, the conductor layer 16b covering the back surface of the insulator layer 17b on which the high-frequency device 3 is mounted is patterned by providing a non-formed region in the conductor layer 16b corresponding to the region 18 as shown in FIG. (By this patterning, the region 18 which is a region where the conductor layer 16b is not formed may be filled with an insulator 17c).
However, by providing a non-formation region in the conductor layer 16b near the terminal electrode 19 for the purpose of preventing the occurrence of parasitic capacitance in this way, the electric field distribution in the vicinity of the terminal electrode 19 is reduced when the high-frequency device 3 is operated. It penetrates deeply into the insulator layer 17a through the non-formation region of 16b and couples with the conductor layer 16a in the region 18, and a part of the electromagnetic field passes through another non-formation region of the adjacent conductor layer 16b to another terminal. This caused feedthrough in which a signal leaked to the electrode 19.

On the other hand, the high-frequency device mounting substrate 1 'shown in FIG. 6 improves on this problem. According to FIG. 6, the back conductor layer 6 b covering the back surface of the insulator layer 7 b on which the high frequency device 3 is mounted is not applied to the portion corresponding to the region 8 immediately below the terminal electrode 9 as shown in FIG. 6. Patterning is not performed so as to provide a formation region.
Even when the non-formation region is not provided in the back conductor layer 6b as described above, since the size of the terminal electrode 9 itself is small in the extremely miniaturized high-frequency device 3, the generated parasitic capacitance is very small. Can be ignored. Therefore, parasitic capacitance is not generated between the back conductor layer 6b and the terminal electrode 9, and signal reflection does not occur due to impedance discontinuity.

Further, by not providing a non-forming region corresponding to the region 8 immediately below the terminal electrode 9 in the back surface conductor layer 6b, the electric field distribution in the vicinity of the terminal electrode 9 is insulated through the back surface conductor layer 6b during the operation of the high frequency device 3. The body layer 7a is prevented from entering deeply, and it is possible to suppress the occurrence of feedthrough due to coupling with the back conductor layer 6a.
When the high-frequency device 3 is a piezoelectric filter, according to the simulation result, in the structure of the high-frequency device mounting substrate shown in FIG. 7, a non-formation region is formed in the conductor layer 16 b corresponding to the region 18 near the terminal electrode 19. By providing, the isolation characteristic between the terminal electrodes 19 was -76.5 dB.

In the structure of the present invention shown in FIG. 6, the non-formation region is not provided in the back surface conductor layer 6b corresponding to the region 8 immediately below the terminal electrode 9, so that the high frequency device 3 is a piezoelectric filter. It can be seen that the isolation characteristic between the terminal electrodes 9 is −80.4 dB, and the influence on the isolation characteristic is remarkably improved.
Thus, according to the high frequency device mounting substrate of the present invention, when the high frequency device 3 to be mounted is a piezoelectric filter or a duplexer using a piezoelectric filter, the isolation characteristics between the terminal electrodes 9 are impaired. There will be no such thing.

Moreover, since the occurrence of feedthrough can be suppressed, the out-of-band attenuation characteristic can be maintained well.
Further, when the high-frequency device 3 is a duplexer, it is possible to suppress the occurrence of feedthrough. Therefore, both the transmission high-frequency filter and the reception high-frequency filter can maintain the out-of-band attenuation characteristics satisfactorily. It is possible to maintain good isolation characteristics by suppressing signal leakage from the terminal to the receiving terminal.

FIG. 8 is a plan view showing another example of the high-frequency device mounting substrate of the present invention. FIG. 9 is a cross-sectional view of the main part taken along the line CC ′ of FIG.
The high-frequency device mounting substrate 1 has a terminal electrode 9 on which a high-frequency device is mounted at the center of the surface of the circuit board 30 having a structure in which insulator layers 32, 39, and 41 and ground conductor layers 33 and 40 are laminated. Provided. An electronic component 60 such as a resistor, a capacitor, or an integrated circuit is mounted on the surface of the circuit board 30.

A signal electrode 23 to which a central conductor (not shown) of the coaxial connector is connected, and a ground electrode 24 to which an outer peripheral conductor (not shown) of the coaxial connector is connected by solder to the periphery of the surface of the circuit board 30 Is formed.
The terminal electrodes 9 and the signal electrodes 23 are connected by signal lines 2 that extend radially from the center of the circuit board 30.

Here, a through hole (through hole) 25 is formed along the outer periphery of the circuit board 30 at a portion of the ground electrode 24 on the outer peripheral side of the circuit board 30.
As shown in FIG. 9, a conductor layer 27 is attached to the inner surface of the through hole 25. The conductor layer 27 electrically connects the ground electrode 24 and the ground conductor layers 33 and 40.
In addition, a predetermined terminal to be grounded among the terminal electrodes 9 is connected to a ground conductor layer 33 immediately below the terminal electrode 9 via a via conductor (not shown) filled with a conductor.

When measuring the characteristics of a high-frequency device (not shown) using the high-frequency device mounting substrate 1 of the present invention, first, cream solder or the like is applied to the terminal electrode 9 and this corresponds to the high-frequency device. A terminal (not shown) is brought into contact and heated above the melting temperature of the cream solder. Thus, the high frequency device is mounted on the high frequency device mounting substrate 1.
Next, a coaxial connector (not shown) is joined to the signal electrode 23 and the outer peripheral conductor of the coaxial connector to the ground electrode 24 using solder and a soldering iron.

At that time, due to the presence of the through hole 25, the molten solder flows from the ground electrode 24 into the through hole 25 and enters the through hole 25. In this way, solder is continuously formed from the inside of the through hole 25 to the outer peripheral conductor 45 (see FIG. 22) of the coaxial connector.
For this reason, the strong connection between the high-frequency device mounting substrate 1 and the coaxial connector can be ensured. Therefore, even when a physical load is applied from a cable or the like connected during measurement, the probability that the central conductor of the coaxial connector and the signal electrode 23 are disconnected can be extremely reduced.

  In addition, the outer peripheral conductor of the coaxial connector and the ground conductor layers 33 and 40 are located in the position closest to the ground electrode of the measuring instrument via the ground electrode 24 and the conductor layer 27 in the through hole 25 in the high-frequency device mounting substrate 1. Since the connection can be made, the parasitic inductance due to the physical distance between the ground electrode of the measuring instrument and the ground conductor layers 33 and 40 can be reduced, and therefore the characteristics of the high-frequency device can be measured more accurately. it can.

Next, still another example of the embodiment of the present invention will be described.
In this example, the plan view of the high-frequency device mounting substrate 1 is the same as that of FIG. 8, but the second ground electrode 28 is provided on the back surface of the circuit board 30 facing the ground electrode 24.
In FIG. 10, the top view of the back surface of the high frequency device mounting substrate 1 of this example is shown. Further, FIG. 11 shows a cross-sectional view of the main part of this example cut along the line CC ′ of FIG. The difference between FIG. 11 and FIG. 9 is that in FIG. 11, the second ground electrode 28 is provided on the back surface of the high-frequency device mounting substrate 1.

The second ground electrode 28 is electrically connected to the ground electrode 24 on the surface and the ground conductor layers 33 and 40 inside through the conductor layer 27 on the inner surface of the through hole 25.
FIG. 12 shows a cross-sectional view of the main part taken along the line DD ′ of FIG. 8 when the high-frequency device mounting substrate 1 of this example and the coaxial connector are joined by solder.
As shown in FIG. 12, solder 36 is continuously present from the back surface side of the high-frequency device mounting substrate 1 to the outer peripheral conductor on the front surface side through the through hole 25 with respect to the outer peripheral conductor (not shown) of the coaxial connector. Therefore, the ground electrode 24 of the high-frequency device mounting substrate 1 and the outer peripheral conductor of the coaxial connector can be connected more firmly.

  Further, when the ground electrode 24 and the outer peripheral conductor of the coaxial connector are connected by the solder 36, the heat of the soldering iron is transferred from the solder 36 existing on one surface to the other surface via the solder 36 in the through hole 25. Since it quickly propagates to the existing solder 36, the solder 36 on both sides can be melted simultaneously. As a result, the amount of solder on both sides is equalized, so that the stress and load applied to the central conductor 44 of the coaxial connector and the signal electrode 23 of the high-frequency device mounting substrate 1 can be reduced.

  Also, when removing the coaxial connector, the solder 36 on both sides can be melted at the same time, so that the removal operation can be completed easily in a short time. Therefore, the mounted high frequency device can be removed without deteriorating its characteristics. Moreover, these can be reused without damaging the coaxial connector or the high-frequency device mounting substrate 1.

  Further, the outer peripheral conductor of the coaxial connector is grounded at a position closest to the ground electrode of the measuring instrument via the ground electrode 24, the second ground electrode 28 and the conductor layer 27 in the through hole 25 in the high-frequency device mounting substrate 1. Since the conductor layer 33 can be connected, the parasitic inductance caused by the physical distance between the ground electrode of the measuring instrument and the ground conductor layer 33 can be reduced. Therefore, the characteristics of the high-frequency device can be measured more accurately. What can be done is the same as in the above embodiment.

Next, still another example of the embodiment of the present invention will be described.
13A and 13B are plan views of the surface of the high-frequency device mounting substrate 1 of this example.
In this example of FIG. 13A, a through hole 25 is formed in a portion of the surface of the high-frequency device mounting substrate 1 on the outer peripheral side of the circuit board 30 of the ground electrode 24, and at a portion of the ground electrode 24 opposite to the signal line 3. Further, a through hole 25 ′ is arranged from the outer periphery of the circuit board 30 toward the center.

In this example of FIG. 13B, the through hole 25 is not formed, and instead, a through hole 25 ′ is arranged from the outer periphery of the circuit board 30 toward the central portion at a portion opposite to the signal line 3 of the ground electrode 24. did.
FIG. 14 is a cross-sectional view of an essential part taken along line EE ′ of FIGS. 13A and 13B when a coaxial connector is connected to the high-frequency device mounting substrate 1 with solder 36.
Furthermore, FIG. 15 shows a cross-sectional view of the main part similar to FIG. 14 in the case where the through hole 25 ′ is not provided as a comparative example.

When the through hole 25 ′ is not provided for the ground electrode 24, the distribution of the solder 36 existing on the upper surface of the ground electrode 24 and the upper surface of the signal electrode 23 is shown in FIG. Therefore, if the amount of solder is large, the solder may be short-circuited.
On the other hand, in the case of this example, the solder 36 flows into the through hole 25 ′ as shown in FIG. 14, so that the solder 36 existing on the upper surface of the ground electrode 24 is moved away from the signal electrode 23 slightly. Can be distributed as follows. Therefore, it is possible to make it difficult to short-circuit the signal electrode 23 and the ground electrode 24 via the solder 36.

Here, the case where there is no second ground electrode 28 on the back surface is shown, but the second ground electrode 28 may be provided on the back surface of the high-frequency device mounting substrate 1 as in the examples shown in FIGS. I do not care.
Note that the surface ground conductor layer 4 may be provided along the signal line 2 on the surface of the circuit board 30 described so far with reference to FIGS.

FIG. 16 is a plan view of the surface of the high-frequency device mounting substrate 1 of this example in which the surface ground conductor layer 4 and the ground electrode 24 are connected.
With such a configuration, the surface ground conductor layer 4 can be connected to the ground electrode of the measuring instrument with the smallest parasitic inductance. Therefore, of the signal terminals of the high-frequency device, The potential can be brought close to the ground potential of the measuring instrument with a smaller parasitic inductance.

The high-frequency device mounting substrate 1 of the present invention can be applied to communication equipment.
That is, the high-frequency device mounting substrate 1 of the present invention can be used in a communication device including one or both of a receiving circuit and a transmitting circuit.
The transmission circuit is, for example, a circuit that places a transmission signal on a carrier frequency with a mixer, attenuates an unnecessary signal with a bandpass filter, then amplifies the transmission signal with a power amplifier, and transmits it from an antenna through a duplexer. is there.

The receiving circuit receives the received signal with an antenna, amplifies the received signal that has passed through the duplexer with a low noise amplifier, then attenuates an unnecessary signal with a bandpass filter, and separates the signal from the carrier frequency with a mixer. A circuit for extracting a signal.
By mounting the duplexer or band-pass filter on the high-frequency device mounting substrate 1 of the present invention and incorporating the duplexer or the band-pass filter into the communication device, a communication device having excellent characteristics on which the high-frequency device mounting substrate 1 of the present invention is mounted can be realized.

Next, a method for evaluating a high frequency device using the high frequency device mounting substrate 1 will be described.
The high-frequency device mounting substrate 1 is used for the purpose of performing non-defective product determination in the characteristic inspection process of the high-frequency device mass production process and for the purpose of evaluating the characteristics of the developed product.
Specifically, in the case of a duplexer using a piezoelectric filter as a high-frequency device, a large number of piezoelectric filters are collectively formed on a wafer made of a piezoelectric material, and then the piezoelectric filter is cut into individual pieces. Then, each piezoelectric filter is flip-chip mounted on a predetermined circuit board in a flip-chip manner to obtain a duplexer, and the obtained duplexer is mounted on the high-frequency device mounting board 1 to determine non-defective products. Since the duplexer cannot be bonded to the high frequency device mounting substrate 1 with solder in the characteristic inspection process for determining the non-defective product, the connection between the duplexer and the high frequency device mounting substrate 1 is a terminal electrode on the high frequency device mounting substrate 1. This is done via a contact pin or the like. In this case, in order to stably measure the characteristics, the high frequency device mounting substrate 1 is fixed on a base such as brass or aluminum together with a jig for fixing the contact pin and a guide for fixing the mounting position of the duplexer, and the upper part of the duplexer. By pressing with a more constant pressure, the connection with the contact pin is made constant.

  In this state, as described above, the coaxial cable is connected to the signal electrode 23 and the ground electrode 24 of the high-frequency device mounting substrate 1 by soldering, and the characteristics of the high-frequency device are evaluated.

<Example 1>
FR-4 (glass epoxy resin) was used as a material for the insulator layer (circuit board) of the high-frequency device mounting board.
A grounding conductor layer was formed in a single layer on the surface of the circuit board, and an insulating layer having a thickness of 0.1 mm and a conductor layer covering the back surface were alternately repeated three times on the back side of the circuit board.

The width of the signal line arranged on the surface of the circuit board was 0.13 mm, the thickness was 0.06 mm, and the gap W between the signal line and the ground conductor layer installed on both sides thereof was 1 mm. The signal lines are arranged so as to extend radially from the center of the circuit board as shown in FIGS.
The conductor layer covering the back surface of each insulator layer covers the entire back surface of the insulator layer.

Installed on the surface by providing via conductors that penetrate the first to third layers of the insulator layer at a constant interval of 0.7 mm at a position 0.5 mm from the side along the signal line side of the ground conductor layer The ground potential of the ground conductor layer was stabilized. The characteristic impedance of the signal line was designed to be 50Ω.
In the embodiment of the high-frequency device mounting substrate of the present invention having such a structure, an ultra-small 800 MHz band duplexer having a size of a surface facing the mounting substrate of 2.5 mm × 2.0 mm is mounted, and the measurement wiring is mounted on the signal line. As a result, the isolation characteristics were measured.

Further, as a comparative example, the same applies to a high-frequency device mounting substrate in which the conductor layer on the back surface of the first insulator layer immediately below the duplexer mounting position is patterned in the region near the terminal electrode and the non-conductive layer formation region. Measurements were made. FIG. 17 is a graph showing the measurement results of the isolation characteristics.
In FIG. 17, the horizontal axis represents frequency (Frequency, unit: MHz), and the vertical axis represents isolation (Isolation, unit: dB).

The solid characteristic curve indicates the result of the comparative example, and the broken characteristic curve indicates the result of the example of the present invention.
As can be seen from the graph shown in FIG. 17, the transmission band (824 to 849 MHz) is obtained by covering the region immediately below the duplexer mounting position with a conductor layer formed on the back surface of the insulator layer as in the embodiment of the present invention. The isolation characteristics at 10 nm were greatly improved to about 10 dB.
<Example 2>
A high-frequency device mounting substrate 1 having the structure shown in FIG. 16 was produced.

The signal line 2 extends radially from the terminal electrode 9, and the structure of the region F to which the coaxial connector is connected is as shown in FIG.
FIG. 18 is an enlarged view of a region F indicated by a broken line in FIG. The number and position of the through holes 25 are as shown in FIG.
In addition, there are three portions including the region F as shown in FIG. 16 to which the coaxial connector is connected, but all of them have the shape shown in FIG.

FIG. 19 shows an enlarged view of the back surface of the portion corresponding to FIG. A second ground electrode 28 opposed to the two ground electrodes 24 on the surface of the circuit board 30 was formed as a series. In FIG. 19, 4 ′ indicates a ground conductor layer formed on the back surface of the circuit board 30.
The cross-sectional view of the main part of the circuit board 30 is the same as FIG.
As a material of the insulator layers 32, 39, and 41 of the circuit board 30, FR-4 (glass epoxy resin) is used as the ground conductor layers 33 and 40, the ground electrode 24, the second ground electrode 28, and the back surface ground conductor layer. Copper was used as the 4 'material.

The thickness of the insulator layer 32 and the insulator layer 41 is 0.1 mm, respectively, and the thickness of the insulator layer 39 is 1 mm. Moreover, the thickness of the ground conductor layer 33 and the ground conductor layer 40 is 0.035 mm, respectively. The thicknesses of the ground electrode 24 and the second ground electrode 28 are each 0.06 mm. The width of the signal line 2 on the surface of the circuit board 30 is 0.13 mm, the width w ₁ of the signal electrode 23 to which the central conductor 44 of the coaxial connector is connected is 0.6 mm, the lateral width w ₂ of the ground electrode 24 is 5 mm, The gap w ₃ with the ground electrode 24 was 0.85 mm.

The characteristic impedance of the signal line 2 was designed to be 50Ω. The vertical width w ₄ of the ground electrode 24 was 3 mm. The width w ₅ of the second ground electrode 28 on the back surface of the circuit board 30 was 13 mm, and the width w ₆ was 3 mm. Further, a through hole 25 having a radius of 0.3 mm that penetrates the circuit board 30 and the second ground electrode 28 on the back surface of the circuit board 30 is formed on the ground electrode 24 by 0.6 mm from the inside of the ground electrode 24, and the outer periphery of the ground electrode 24. Six pieces were provided at intervals of 0.8 mm from a position of 0.3 mm from the portion (the outer peripheral side of the circuit board 30). Each through hole 25 is provided with a conductor layer 27 made of copper on the inner surface, and grounding of the front surface ground conductor layer 4 connected to the ground electrode 24 and the back surface ground conductor layer 4 ′ connected to the second ground electrode 28. The potential was stabilized.

Further, as a comparative example, a high frequency device mounting substrate was manufactured in which all the designs except for not providing the through hole 25 were the same as those in the above example.
About the examples and comparative examples of the present invention thus produced, each mounted with a high-frequency device and attached with a coaxial connector, then measured the high-frequency characteristics via the signal line 2, and then removed the coaxial connector, The high frequency characteristics were measured again.

The measurement at this time was performed by bringing a high-frequency probe (product name: Picoprobe 40A-GS-600-DP) directly into contact with the terminal electrode of the high-frequency device.
As the high frequency device, an 800 MHz band duplexer using a small high frequency filter having a size of a surface connected to the terminal electrode 9 of 2.5 mm × 2.0 mm and a height of 0.6 mm was used.

First, cream solder was applied to the terminal electrode 9 for both the example and the comparative example, and this high frequency device was mounted. Then, the cream solder was melted using a hot plate, and the terminal of the high-frequency device and the terminal electrode 9 were connected.
Next, a coaxial connector was attached. For both the example and the comparative example, thread solder (Sn—Cu—Ag: melting point 217 ° C.) is melted to the signal electrode 23, the ground electrode 24, and the second ground electrode 28 using a soldering iron, and high frequency A coaxial connector was attached to the device mounting board 1.

When the comparative example is used, even if heat is applied to the thread solder for the same time, the amount of melting is not constant, and the solder between the ground electrode 24 and the second ground electrode 28 cannot flow directly. It has been very difficult to make the amount of solder between 24 and the ground electrode 8 uniform.
On the other hand, in the embodiment, when the solder 36 of the signal electrode 23 and the ground electrode 24 is melted using a soldering iron, the solder 36 on the second ground electrode 28 is also heated through the through hole 25. Therefore, the solder 36 on the second ground electrode 28 can be melted at the same time, and since the melted solder 36 flows through the through hole 25, the ground electrode 24 and the second ground electrode Thus, it was possible to eliminate the deviation of the solder amount with respect to 28.

Next, the coaxial connector connected to the high frequency device mounting substrate 1 and the measuring device were connected by a cable, and the high frequency characteristics of the high frequency device were measured.
During this measurement, in the comparative example, there was one in which the coaxial connector was disconnected due to the force applied by the cable connecting the coaxial connector and the measuring device, but in the example, as shown in FIG. On the other hand, the solder 36 can be continuously present from the second ground electrode 28 side on the back surface of the high-frequency device mounting substrate 1 through the through hole 25 to the outer peripheral conductor on the surface ground electrode 24 side. The high frequency device mounting substrate 1 and the coaxial connector could be connected to each other, and the coaxial connector was never detached.

Next, the coaxial connector was removed from the high frequency device mounting substrate 1.
In the case of the comparative example, in order to remove the coaxial connector, first, the solder of the second ground electrode 28 is removed using a solder sucker (manufacturer: manufactured by Hakko Co., Ltd., product name: solder removal station 24V474). And the high-frequency device mounting substrate 1 are held in a state in which only the solder on the signal electrode 23 and the ground electrode 24 is held, and then the solder between the signal electrode 23 and the ground electrode 24 is melted to mount the coaxial connector on the high-frequency device. It was removed from the substrate 1.

On the other hand, in the case of the embodiment, when the solder 36 of the signal electrode 23 and the ground electrode 24 is melted using a soldering iron, the solder 36 on the second ground electrode 28 through the through hole 25. In addition, since heat is conducted, the solder 36 on the second ground electrode 28 can be melted at the same time. For this reason, the coaxial connector was able to be removed very easily in a short time as compared with the comparative example.
In this way, the embodiment does not require the use of a solder sucker as compared with the comparative example, and by simply applying heat to the solder 36 on one side using a soldering iron, the solder 36 on the other side is melted to form a coaxial connector. And the time during which heat is applied to the high-frequency device mounting substrate 1 and the high-frequency device can be extremely shortened.

Next, the high frequency device was removed. Both the example and the comparative example were placed on a hot plate and heated to melt the cream solder, and the high frequency device was removed using tweezers.
Thereafter, the high frequency characteristics of the removed high frequency device were measured. As a result, when the high-frequency device mounting substrate 1 of the example of the present invention was used, there was no high-frequency device whose characteristics deteriorated before and after the above series of operations, but when the high-frequency device mounting substrate of the comparative example was used. High-frequency devices with deteriorated high-frequency characteristics were generated by heat applied during installation and removal of the coaxial connector.
<Example 3>
The plan view of the surface of the high-frequency device mounting substrate 1 is the same as that of the first embodiment, but as shown in the enlarged view of FIG. 20, the through hole located at the end of the ground electrode 24 opposite to the signal electrode 23 The difference is that two through-holes 25 ′ having the same dimensions as the through-holes 25 are provided from 25 A toward the central part from the outer peripheral part of the circuit board 30.

In the second embodiment, as shown in FIG. 15, the distribution of the solder 36 existing on the upper surface of the ground electrode 24 and the upper surface of the signal electrode 23 is close due to the surface tension of the solder 36. There was a case where a short circuit occurred via the solder 36.
As in this embodiment, by providing the through hole 25 'in the ground electrode 24, the solder 36 flows into the through hole 25' as shown in FIG. 14, so that the solder 36 existing above the ground electrode 24 is replaced with the signal electrode. Therefore, the signal electrode 23 and the ground electrode 24 were not short-circuited via the solder 36.

In addition, this invention is not limited to the above embodiment and an Example, A various change may be added in the range which does not deviate from the summary of this invention.
For example, the material of the insulator layer of the circuit board is not limited to the materials listed in the following examples, but is mainly composed of organic materials such as tetrafluoroethylene and BT resin, ceramics such as alumina, or alumina as a main component. Inorganic materials such as glass ceramics may be used.

Further, the number of laminated conductor layers covering the insulator layer and the back surface of the insulator layer may be arbitrary. In the above example, the ground conductor layer 28 is further provided on the back side in addition to the ground conductor layer 33. However, the ground conductor layer 28 may be omitted.
Moreover, although the shape of the through hole 25 is shown as a circle in FIG. 8 and the like, the shape may be arbitrary. In addition, the position of the through hole 25 is also provided in a region slightly entering the center side from the outer periphery of the circuit board 30 toward the center, but the through hole is formed in the outer periphery of the circuit board 30 so as to open in the length direction. Then, the conductor layer 27 is attached to the inner surface of the circuit board 30 so as to connect the ground electrode 24, the ground conductor layers 33 and 40, and the second ground electrode 28 through the outer peripheral side surface of the circuit board 30. It may be.

Further, the characteristic impedance of the signal line is not limited to 50Ω, and may be matched to the characteristic impedance of the system using the high frequency device.
In the above description, the signal lines are arranged on the surface of the high-frequency device mounting substrate. However, as shown in FIG. 21, some of the signal lines are arranged in the insulator layer. It doesn't matter. In this case, since the signal lines are not opposed to each other in the thickness direction by providing the signal lines in different layers, it is possible to further improve the isolation characteristics between the signal lines. The influence on the characteristics can be further reduced, or the characteristics can be exhibited better.

Further, in the figure used for the description, there is shown a case where there are three terminals (a set of the signal electrode 23 and the ground electrode 24) to which the high-frequency device mounting substrate 1 and the coaxial connector are connected. It may be arbitrary according to the number of terminals.
Moreover, you may protect the part which does not need to contact solder among the surfaces of the high frequency device mounting substrate 1 with a soldering resist etc. By doing so, it is possible to make the solder exist only in a portion where the solder is desired to be in contact, and it is possible to prevent the conductors such as the signal line 2 from being short-circuited through the extra solder.

Furthermore, the high-frequency device is not limited to a piezoelectric filter or a duplexer, and can be applied to all high-frequency devices used in high-frequency signal processing applications such as mobile communication devices, wireless LAN, and ETC.
Further, the scope of the present invention extends to a configuration in which the configurations described in the claims are arbitrarily combined.

It is a top view which shows the state which mounted the high frequency device on the high frequency device mounting board | substrate of this invention. It is a top view of the high frequency device mounting substrate of the present invention. It is principal part sectional drawing cut | disconnected by the A-A 'line | wire of FIG. It is a top view of the high frequency device mounting substrate of the present invention in which the number of signal lines and the installation angle are changed. It is a top view of the high frequency device mounting board of the present invention which changed the number of signal lines 2 and the installation angle. FIG. 6 is a cross-sectional view of the main part taken along line B-B ′ of FIG. 1. It is principal part sectional drawing of the high frequency device mounting board | substrate which concerns on a comparative example. It is a top view which shows the other example of the high frequency device mounting board | substrate of this invention. It is principal part sectional drawing cut | disconnected by the C-C 'line | wire of FIG. 3 is a back view of a high-frequency device mounting substrate having a second ground electrode 28. FIG. FIG. 9 is a cross-sectional view of a main part of a high-frequency device mounting substrate having a second ground electrode 28 cut along line C-C ′ in FIG. 8. FIG. 9 is a cross-sectional view of a principal part taken along line D-D ′ of FIG. 8 when the high-frequency device mounting substrate and the coaxial connector are connected by solder. It is a top view of the surface which shows the other example of the high frequency device mounting substrate of this invention. It is a top view of the surface which shows the other example of the high frequency device mounting substrate of this invention. It is principal part sectional drawing which cut | disconnected the high frequency device mounting board | substrate shown to FIG. 13A by the E-E 'line | wire. It is principal part sectional drawing of the high frequency device mounting board | substrate of a comparative example. It is a top view of the surface which shows the other example of the high frequency device mounting substrate of this invention. It is the graph which compared the isolation characteristic in the Example and comparative example of this invention. It is an enlarged view of the area | region F in FIG. FIG. 6 is an enlarged view of the back surface of a region F. 10 is an enlarged view showing another structure in the region F. FIG. It is sectional drawing which shows the high frequency device mounting substrate of this invention which formed the signal wire | line in the circuit board. It is a schematic perspective view which shows a common high frequency device mounting board | substrate, the high frequency device connected to it, and a coaxial connector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High frequency device mounting substrate 2, 2a-2c Signal line 3 Duplexer 4 Surface grounding conductor layer 5 Through conductor 6 Back surface conductor layer 7 Insulator layer 8, 18 Area | region 9 Terminal electrode 10 High frequency device mounting substrate 14 Grounding conductor layer 16a, 16b Conductor Layers 17a, 17b Insulator layer 23 Signal electrode 24 Ground electrode 25 Through hole 27 Conductor layer 28 Ground electrode 30 Circuit boards 32, 39, 41 Insulator layer 33, 40 Ground conductor layer 36 Solder 44 Central conductor 60 Electronic component

Claims (17)

A circuit board having a conductor layer on the back surface or inside of the insulator layer;
A plurality of terminal electrodes installed on the surface of the circuit board for mounting a high-frequency device;
A plurality of signal lines installed on the circuit board and connected to the terminal electrodes;
The signal line extends radially from the terminal electrode, and a straight line obtained by virtually extending any one signal line from the terminal electrode and another arbitrary signal line virtually extending from the terminal electrode. A high-frequency device mounting board in which the extended straight line does not form the same straight line.   The high frequency device mounting substrate according to claim 1, wherein the two extension lines intersect at one point.   The high frequency device mounting substrate according to claim 1, wherein the two extension lines are parallel to each other.   The high-frequency device mounting substrate according to any one of claims 1 to 3, wherein the terminal electrode is disposed in a central portion of the circuit board. A ground conductor layer is installed on both sides of the signal line on the surface of the circuit board,
The distance W between the signal line and the ground conductor layer is larger than the distance t between the signal line and the conductor layer formed on the back surface or inside the insulator layer. The high-frequency device mounting substrate according to the above.   The said grounding conductor layer is connected with the several through-conductor which penetrates the said circuit board and is electrically connected with the said conductor layer formed in the back surface or the inside of the said insulator layer. High frequency device mounting board.   The high-frequency device mounting substrate according to claim 1, wherein the high-frequency device is a piezoelectric filter.   The high-frequency device mounting substrate according to claim 1, wherein the high-frequency device is a duplexer.   A communication device on which the high-frequency device mounting substrate according to any one of claims 1 to 8 is mounted. A signal electrode disposed in a peripheral portion of the surface of the circuit board, connected to the signal line, and connected to a central conductor of a coaxial connector;
A ground electrode disposed on the periphery of the surface of the circuit board, and connected to the outer peripheral conductor of the coaxial connector using solder;
In the ground electrode, a through-hole penetrating the circuit board is formed in a region where the solder adheres,
The high-frequency device mounting substrate according to any one of claims 1 to 8, wherein a conductor layer is attached to an inner surface of the through hole.   The circuit board is a laminated board in which a plurality of insulator layers are laminated, an inner conductor layer is formed therein, and a conductor layer formed on an inner surface of the through hole is connected to the inner conductor layer. The high-frequency device mounting substrate according to claim 10.   A second ground electrode is formed on the back surface of the circuit board corresponding to the ground electrode, and the second ground electrode is connected to the circuit via the conductor layer formed on the inner surface of the through hole. The high-frequency device mounting substrate according to claim 10 or 11, which is connected to the ground electrode on the surface of the substrate.   The high-frequency device mounting substrate according to any one of claims 10 to 12, wherein a plurality of the through holes are arranged in a portion of the ground electrode along a periphery of the circuit board.   The high-frequency device mounting substrate according to claim 13, wherein the through-hole is further disposed from a periphery of the circuit board toward a central portion at a portion of the ground electrode opposite to the signal line.   The high-frequency device mounting according to any one of claims 10 to 14, wherein the through hole is disposed from a periphery of the circuit board toward a central portion at a portion of the ground electrode opposite to the signal line. substrate.   The high-frequency device mounting board according to claim 10, wherein a surface ground conductor layer formed along the signal line is connected to the surface of the circuit board to the ground electrode. A method for evaluating characteristics of a high-frequency device mounted on a high-frequency device mounting substrate,
Mounting the high-frequency device on the high-frequency device mounting substrate according to any one of claims 1 to 16;
Connecting the measurement wiring to the high-frequency device mounting substrate;
A characteristic evaluation method for a high-frequency device, including a characteristic inspection step for performing a characteristic inspection of the high-frequency device mounted on the high-frequency device mounting substrate.

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