WO2007049382A1

WO2007049382A1 - High-frequency module

Info

Publication number: WO2007049382A1
Application number: PCT/JP2006/312896
Authority: WO
Inventors: Yuya Dokai
Original assignee: Murata Manufacturing Co., Ltd.
Priority date: 2005-10-27
Filing date: 2006-06-28
Publication date: 2007-05-03

Abstract

A high-frequency module with a filter, which can be miniaturized, exhibits an adequate amount of out-of-band attenuation, and can effectively suppress the out-of-band spurious. In a high-frequency module (1), an RF circuit part is provided on a first substrate (2), a high-frequency element is mounted on a second substrate (3), a line connecting the high-frequency element and the RF circuit is provided with a transmission line (9) and a wiring line (17), the impedance of the transmission line (9) is made lower than the impedance of the wiring line (17), and the input impedance ZS11 when viewed from the side of the wiring line (17) of the transmission line (9) is made higher than the input impedance ZS22 when viewed from the side of the high-frequency element of the transmission line (9).

Description

Specification

High frequency module

Technical field

The present invention relates to a high-frequency module used in a high-frequency circuit such as a mobile phone, and more particularly to a high-frequency module that includes a high-frequency element and an RF circuit unit and is integrated.

Background art

In mobile communication devices and the like, it is desired to reduce the size of a high-frequency module including a high-frequency element and a high-frequency circuit portion connected to the high-frequency element. In order to achieve good frequency characteristics, various circuits in which a bandpass filter is connected to a high-frequency element have been proposed.

[0003] For example, Patent Document 1 below discloses an LC filter using a line connected to an antenna. FIG. 25 is a perspective view schematically showing the filter described in Patent Document 1. As shown in FIG.

[0004] In the filter 101, a plurality of dielectric substrates 102 to 106 are laminated via metal base plates 107 to L10. Each metal base plate 107-: In L10, slots 107a-l10a are formed substantially at the center. In the metal ground planes 107 to 109, via metal patches 111 to 113 are arranged in the slots 107a to 109a so as not to contact the metal ground planes 107 to 109. Then, the via hole electrode 114 is provided so as to penetrate the portion where the above-mentioned slots 107a to l10a are provided so as to penetrate the laminated body formed by laminating the dielectric substrates 102 to 106! ing. The via hole electrode 114 is electrically connected to the via metal patches 111 to 113. The upper end of the via-hole electrode 114 is electrically connected to the microstrip line 115. The microstrip line 115 is formed on the upper surface of the dielectric substrate 106 and is electrically connected to the antenna element.

On the other hand, the lower end of the via-hole electrode 114 is electrically connected to the microstrip line 116 on the lower surface of the dielectric substrate 102. The microstrip line 116 is electrically connected to the high frequency circuit part. Here, the via hole electrode 114, that is, the inductivity of the line, and the via metal patch 111.

To 113 and the metal base plate 107 to 109, respectively, and using the capacitance respectively, L

C filter is configured!

That is, the filter 101 is configured by using a line portion that connects an antenna and a high-frequency circuit to which the antenna is connected. Therefore, the high-frequency module including the filter can be downsized. It is possible to plan.

Patent Document 1: JP 2000-101377 A

Disclosure of the invention

[0008] In the filter described in Patent Document 1, as described above, a line electrically connecting an antenna and a circuit to which the antenna is connected is used as a coil, and the line and the ground potential are interposed between the line and the ground potential. The LC filter was formed by configuring the capacitor. However, with the configuration described in Patent Document 1, it is difficult to obtain a sufficient amount of attenuation because the L value of the coil connecting the capacitors cannot be increased, and spurious can be effectively suppressed. It was also difficult. In addition, in order to configure a capacitor, via metal patches 111 to 113 arranged at a predetermined interval from the metal ground plates 107 to 109 must be formed on the metal ground plates 107 to 109 with high accuracy. I helped. That is, in order to configure the filter, the slots 107a to 109a and the metal patches 111 to 113 must be formed with high precision.

[0009] An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to reduce the amount of attenuation that can be achieved simply by configuring an LC filter using a line portion formed by connecting a high-frequency element and a high-frequency circuit. It is an object of the present invention to provide a high-frequency module that can be reduced in size, can suppress spuriouses effectively, and can be easily manufactured.

According to the present invention, an RF circuit unit, a high frequency element, and a line connecting the RF circuit unit and the high frequency element are provided, and the stray capacitance of the line force is connected to a ground potential. A high-frequency module in which the line is used as a low-pass filter, provided on a first substrate, the RF circuit unit provided on the first substrate, a second substrate, and a second substrate. The high-frequency element and the transmission line, one end connected to the high-frequency element, one end connected to the transmission line, and the other end to the R A wiring line connected to an F circuit, wherein the transmission line is provided on the second substrate, the impedance of the transmission line being lower than the impedance of the wiring line, and the transmission line An input impedance viewed from the wiring line side is set higher than an input impedance viewed from the high-frequency element side force of the transmission line. Preferably, a ratio of an input impedance viewed from the high frequency element side of the transmission line to an input impedance viewed from the wiring line side of the transmission line is 0.63 or less.

[0011] In a specific aspect of the high-frequency module according to the present invention, an input impedance of the wiring line viewed from the RF circuit side is set lower than an input impedance of the wiring line viewed from the transmission line side. .

[0012] In yet another specific aspect of the high-frequency module according to the present invention, the transmission line is a coplanar line.

[0013] In still another specific aspect of the high-frequency module according to the present invention, the transmission line is configured by a strip line, and a ground electrode is disposed above and below the portion where the strip line is provided. And

[0014] In still another specific aspect of the high-frequency module according to the present invention, the high-frequency element includes:

It is mounted on one main surface of the board 2 and in the center.

In still another specific aspect of the high-frequency module according to the present invention, the high-frequency element is

The transmission line is mounted at a position shifted from the center of the first substrate, and one end of the transmission line is connected to a portion where the high-frequency element is mounted.

In yet another specific aspect of the high-frequency module according to the present invention, the high-frequency element is an antenna element.

(The invention's effect)

In the high-frequency module according to the present invention, a high-frequency element is provided on the second substrate, an RF circuit unit is provided on the first substrate, and a line connecting the high-frequency element and the RF circuit The path includes a transmission line having one end connected to the high-frequency element, and a wiring line having one end connected to the transmission line and the other end connected to the RF circuit. The impedance of the transmission line is made lower than the impedance of the wiring line, and the input line seen from the wiring line side of the transmission line. Since the impedance is higher than the input impedance seen from the high-frequency element side of the transmission line, the LC filter is configured using L by the wiring line and the capacitance of the transmission line. Therefore, a bandpass filter composed of an LC filter can be configured using the high-frequency module line itself, and the miniaturization of the high-frequency module can be promoted.

[0018] As described above, the transmission force has a capacitive characteristic of the transmission line due to the inductivity of the wiring line and the input impedance viewed from the wiring line side of the transmission line higher than the input impedance viewed from the high-frequency element side force. Can be used to obtain a sufficiently large attenuation compared to a filter using a conventional line, and can effectively suppress spurious and obtain a good frequency characteristic. It becomes.

[0019] Since the electrode pattern and the patch for forming the capacitor are not required, the manufacturing force can be easily manufactured.

[0020] When the ratio of the input impedance viewed from the high-frequency element side of the transmission line to the input impedance viewed from the wiring line side of the transmission line is 0.63 or less, as will be apparent from the experimental example described below, A much larger out-of-band attenuation can be obtained.

[0021] In the present invention, when the input impedance force viewed from the RF circuit side of the wiring line is lower than the input impedance of the transmission line side force of the wiring line, the attenuation is further increased. be able to.

[0022] When the transmission line is a coplanar line, a planar coplanar line can be easily formed on the second substrate, and around the coplanar line on the main surface of the second substrate. A large ground pattern can be formed, whereby the characteristics of the high-frequency device can be further improved.

[0023] When the transmission line is provided with a strip line provided in the second substrate and the ground electrodes are arranged above and below the strip line, the strip line can be electromagnetically shielded by the ground. As a result, the filter characteristics can be further stabilized.

[0024] When the high-frequency element is mounted in the center of the main surface of the second substrate, the second substrate is included. Therefore, the mechanical strength of the entire high-frequency module can be increased, and the module characteristics can be stabilized even in an environment such as an impact.

[0025] In the case where the high frequency element is arranged in a portion where the central force is shifted on the main surface of the second substrate, the transmission line connected to the high frequency element can be lengthened, whereby the transmission line and The L part of the line including the wiring line can be increased. Therefore, the amount of attenuation can be further increased, and spurious can be more effectively suppressed.

[0026] When the high-frequency element is an antenna element, the antenna element emits a strong radio wave. However, according to the present invention, the antenna element can be easily shielded from other components. Therefore, it is possible to obtain a high-frequency module with less interference between the antenna element and other components. Furthermore, it is preferable to arrange an antenna element at the center of the ground electrode because the antenna characteristics can be further improved.

Brief Description of Drawings

[0027] FIG. 1 is a partially cutaway perspective view showing a main part of a high-frequency module according to an embodiment of the present invention.

FIG. 2 is a front cross-sectional view of a high-frequency module according to an embodiment of the present invention.

FIG. 3 is a plan view of a second substrate in the high-frequency module according to one embodiment of the present invention.

FIG. 4 is a plan view for explaining a frame-like member provided on the first substrate in the high-frequency module of one embodiment of the present invention.

FIG. 5 is a diagram showing a transmission circuit of a filter configured in an embodiment of the present invention.

FIG. 6 is a schematic exploded perspective view for explaining a modification of the transmission line.

FIG. 7 is a schematic plan view of a second substrate for explaining another modification of the transmission line.

FIGS. 8 (a) and 8 (b) are diagrams showing the pass characteristics of a single wiring line in an experimental example of the high-frequency module of the embodiment and an enlarged view of the main part of the pass characteristics.

[FIG. 9] FIGS. 9 (a) and 9 (b) show the reflection characteristics S 11 and the reflection characteristics viewed from the transmission line side of the single RF circuit side wiring line of the high-frequency module in one embodiment of the present invention. Show 22 It is a figure.

[FIG. 10] FIGS. 10 (a) and 10 (b) show the reflection characteristic S11 as seen from the RF circuit side of the wiring line alone of the high-frequency module in one embodiment of the present invention and the reflection characteristic as seen from the transmission line side. It is a Smith chart which shows.

FIG. 11 is a schematic perspective view for explaining the specifications of a coplanar line.

[FIG. 12] FIGS. 12 (a) and 12 (b) are enlarged views showing the pass characteristic of the low-pass filter of the first experimental example and the main part of the pass characteristic.

FIGS. 13 (a) and 13 (b) are diagrams showing a reflection characteristic S11 viewed from the RF circuit side and a reflection characteristic S22 viewed from the antenna element side of the low-pass filter of the first experimental example.

[FIG. 14] FIGS. 14 (a) and 14 (b) are a Smith chart showing the reflection characteristics of the high-frequency module of the first experimental example, which also shows the RF circuit side force, and a Smith chart showing the reflection characteristics S22 seen from the antenna element side. It is a chart.

[FIG. 15] FIGS. 15 (a) and 15 (b) are enlarged views showing the pass characteristics of the coplanar line alone and the pass characteristics in the first experimental example.

[FIG. 16] FIGS. 16 (a) and 16 (b) show the reflection characteristics seen from the coplanar line alone wiring line side in the high frequency module of the first experimental example, and the reflection characteristics seen from the antenna element side side. It is a figure which shows S22.

[FIG. 17] FIG. 17 (a) is an impedance Smith chart of the reflection characteristic S11 seen from the wiring line side of the coplanar line alone in the high-frequency module of the first experimental example, and (B) is seen from the antenna element side. It is an impedance Smith chart of the reflection characteristic S22.

FIGS. 18 (a) and 18 (b) are enlarged views showing the pass characteristics of the high-frequency module of the second experimental example and the main parts of the pass characteristics.

[19] FIGS. 19 (a) and 19 (b) are diagrams showing the reflection characteristic S11 in which the RF circuit side force of the high-frequency module of the second experimental example is also seen and the reflection characteristic S22 in view from the antenna element side.

20] FIG. 20 (a) is a diagram showing an impedance Smith chart of the reflection characteristic S11 in which the RF circuit side force of the high-frequency module of the second experimental example is also seen, and (b) is an antenna element of the high-frequency module. FIG. 10 is a diagram showing an impedance Smith chart of reflection characteristics S22 as seen from the side. FIGS. 21 (a) and 21 (b) are enlarged views showing a pass characteristic of a coplanar line alone and a main part of the pass characteristic in the high frequency module of the second experimental example.

[FIG. 22] FIGS. 22 (a) and 22 (b) show the reflection characteristics seen from the coplanar line alone wiring line side in the high-frequency module of the second experimental example and the reflection characteristics seen from the antenna element side side. It is a figure which shows S22.

[FIG. 23] FIG. 23 (a) is a diagram showing an impedance Smith chart showing the reflection characteristic S11 as seen from the wiring line side of the coplanar line alone in the high-frequency module of the second experimental example, and FIG. It is a figure which shows the impedance Smith chart of the reflective characteristic seen from the antenna element side of this coplanar line.

[FIG. 24] FIG. 24 shows the input impedance as seen from the antenna element side of the transmission line relative to the input impedance ratio Z of the transmission line in the high-frequency module of the present invention.

S11

FIG. 6 is a diagram showing the relationship between the ratio z / z of the impedance z and the attenuation.

S22 S22 S11

FIG. 25 is a schematic perspective view showing an example of a conventional filter.

Explanation of symbols

1 ... High frequency module

2 ··· First board

3 ··· Second substrate

3Α ···· Second board

4, 5 ... Bare chip IC

6, 7… Electronic component elements

8 ... Ground electrode

8a ... Opening

8A ... Ground electrode

9 ... Coplana Line

9a, 9b… End

10 ... Through hole electrode

11 ... Antenna element

12… Conductive connection member 13 ··· Frame member

14… Conductive connection member

15 ... Through hole electrode

16… Resin coating layer

21 ... Ground electrode

21a… Opening

22 ... Stripline

23, 24 ... Ground electrode

31 ... Coplana Line

A: Antenna element mounting area

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

FIG. 2 is a front sectional view of the high-frequency module according to one embodiment of the present invention.

The high frequency module 1 has a structure in which a first substrate 2 and a second substrate 3 are laminated.

[0032] In the present embodiment, the first substrate 2 is composed of a low-temperature fired ceramic multilayer substrate. Bare chip ICs 4 and 5 as high-frequency elements are mounted on the upper surface of the first substrate 2. In addition, other electronic component elements 6, 7 and the like are surface-mounted on the lower surface of the first substrate 2. The bare chip ICs 4 and 5 and the electronic component elements 6 and 7 are electrically connected by wiring provided on the first substrate 2, thereby forming an RF circuit.

On the other hand, the second substrate 3 is made of synthetic resin in the present embodiment. As the synthetic resin, an appropriate synthetic resin such as polyimide, epoxy, and glass epoxy can be used. The second substrate 3 may be made of a material other than synthetic resin, for example, ceramics.

FIG. 3 is a plan view of the second substrate 3. On the upper surface of the second substrate 3, an antenna element is mounted as a high-frequency element in a region surrounded by an alternate long and short dash line A at the center. On the upper surface of the second substrate 3, the ground electrode 8 is formed on almost the entire surface. The ground electrode 8 has an L-shaped opening 8a. In this opening 8a, a copier as a transmission line is formed. Narrain 9 is provided. One end 9a of the coplanar line 9 as a transmission line is electrically connected to the antenna element, and the other end 9b is a through-hole electrode penetrating through the second substrate 3 as shown in FIG. 10 is electrically connected to one end. The lower end of the through-hole electrode 10 reaches the lower surface of the second substrate 3. The ground electrode 8A is also formed on the lower surface of the second substrate 3 in the most part.

As shown in FIG. 2, the antenna element 11 uses a suitable antenna element such as a dielectric antenna for the antenna element 11 mounted on the upper surface of the second substrate 3. be able to.

[0036] In this embodiment, the coplanar line 9 constituting and transmitting the transmission line is a wiring line including the through hole electrode 10 and the conductive connection member 12 connected to the lower end of the through hole electrode 10. , Connected to the RF circuit described above.

FIG. 4 is a plan view for explaining a portion where the conductive connection member 12 is provided. Here, a rectangular frame-shaped frame member 13 is fixed on the first substrate 2. Has been. The rectangular frame-shaped frame member 13 is made of an appropriate synthetic resin such as polyimide. The conductive connection member 12 is embedded so as to penetrate the lower surface from the upper surface of the frame-shaped member 13.

Further, at least one conductive connecting member 12 connects the antenna element 11 and the RF circuit described above, and the force frame member 13 constituting a part of the wiring line through which a signal flows is provided with a duller. A plurality of conductive connection members 14 connected to the ground potential are also provided. The upper end of the conductive connection member 14 is connected to a through-hole electrode 15 provided on the second substrate 3, and the through-hole electrode 15 is electrically connected to the ground electrode 8 provided on the second substrate 3. Connected.

[0039] The lower end of the conductive connection member 14 is electrically connected to the ground potential of the RF circuit.

In the present embodiment, the second substrate 3 side and the RF circuit on the first substrate 2 side are electrically connected by the conductive connection members 12 and 14 provided on the frame member 13. ing.

[0041] A resin coating layer 16 is provided so as to cover the bare chips IC4, 5 (see FIG. 2).

By providing the resin coating layer 16, the bare chip ICs 4 and 5 are sealed with the resin so that the environmental resistance is improved. [0042] Further, since the plurality of conductive connecting members 14 surround the high-frequency circuit portion including the bare chips IC4 and 5, it is possible to suppress deterioration of characteristics due to the electromagnetic field of the antenna element 11 side force. Has been.

[0043] The high-frequency module 1 of the present embodiment is characterized in that the wiring line is provided on the second substrate 3 and includes the coplanar line 9 as the transmission line, the through-hole electrode 10, and the conductive connecting member 12 Thus, a low-pass filter is configured. This will be described more specifically with reference to FIG. 1 and FIG.

FIG. 1 is a partially cutaway perspective view showing an enlarged main part of the high-frequency module of the present embodiment. Here, the antenna element 11 is omitted and a conductive connecting member 12 is provided. Enlarge the end of the side and show it partially! /

[0045] One end 9a of the coplanar line 9 is actually arranged at substantially the center of the substrate 3, and the antenna element 11 is mounted in the center.

In the present embodiment, the above-described through-hole electrode 10 is connected to the other end 9b of the coplanar line 9, and the conductive connecting member 12 is electrically connected to the lower end of the through-hole electrode 10, The through-hole electrode 10 and the conductive connecting member 12 constitute a wiring line 17. The wiring line 17 is connected to the RF circuit of the first substrate 2. The LC filter is composed of the inductivity of the wiring line 17, ie, the L component, and the capacitance of the coplanar line 9, ie, the C component. In this case, the impedance of the coplanar line 9, which is the transmission line, is lower than the impedance of the wiring line, and the input impedance viewed from the wiring line 17 side of the coplanar line is greater than the input impedance viewed from the antenna element 11 side force of the coplanar line 9. As a result, a low-pass filter having good band characteristics and sufficient out-of-band attenuation is configured. That is, as shown in FIG. 5, a low-pass filter composed of an LC filter is configured by the L portion by the wiring line and the C portion by the portion where the coplanar line 9 is provided.

In the present embodiment, a transmission line is configured by the coplanar line 9! However, the transmission line in the present invention can be variously modified. For example, in the modification shown in FIG. 6, a ground electrode 21 is provided in the second substrate 3A at an intermediate height position, and an L-shaped opening 21a is formed in the ground electrode 21. Yes. And the opening 21a Inside, a strip line 22 is arranged. The stripline 22 constitutes the transmission line. In addition, ground electrodes 23 and 24 are arranged above and below the portions constituting the ground electrode 21 and the strip line 22, respectively.

[0048] One end of the strip line 22 passes through an opening (not shown) provided in the ground electrode 23 and is electrically connected to a through-hole electrode electrically connected to the antenna element. . Further, the other end of the strip line 22 is electrically connected to the RF circuit by a through-hole electrode passing through an opening provided in the ground electrode 24.

[0049] When a transmission line having a structure in which the upper and lower sides of the stripline 22 are sandwiched between the ground electrodes 23 and 24 is used, the stripline 22 is sufficiently electromagnetically shielded, so that the filter characteristics are more stable. And can suppress spurious more effectively

In the modification shown in FIG. 7, the antenna element is mounted at a position where the central force on the upper surface of the second substrate 3 is also shifted, more specifically, near the end of the second substrate 3. It is structured as follows. In FIG. 7, the area where the antenna element is mounted is indicated by a one-dot chain line A. Therefore, the length of the coplanar line 31 as a transmission line connected to the antenna element can be increased by forming a meandering shape as shown in the figure. Therefore, the length of the transmission line is lengthened, and as a result, the L portion of the entire transmission line is increased, so that the attenuation can be further increased.

[0051] Thus, the form of the transmission line in the present invention is not limited to the above-described embodiment, and various modifications can be made.

In the present invention, the wiring line connecting the transmission line and the RF circuit also has various through-hole electrodes other than the structure using the conductive connecting member 12 embedded in the frame-shaped member 13 described above. Conductor lines can be used.

[0053] Even if V is shifted, in this embodiment, the impedance of the coplanar line 9 constituting the transmission line is set lower than the impedance of the wiring line 17, and the transmission line is constituted. Since the input impedance viewed from the wiring line side of the coplanar line 9 is higher than the input impedance viewed from the antenna element side force, sufficient attenuation and good spurious suppression characteristics can be realized. This is shown in Figs. 8 to 23. This will be described more specifically with reference to FIG.

[0054] In the following experimental example, a low-pass filter having a center frequency of 5.8 GHz is configured.

FIGS. 8 (a) and 8 (b) are diagrams showing the transmission characteristics of the wiring line 17 alone and the transmission characteristics showing an enlarged main part in the above embodiment. (a) and (b) show the reflection characteristic S 11 on the RF circuit side of the wiring line 17 and the reflection characteristic S22 on the coplanar line 9 side, and FIGS. 10 (a) and (b) show the reflection characteristic S 11 and It is a Smith chart drawn based on S22.

[0056] The impedance on the RF circuit side of the wiring line 17 obtained from FIGS. 9 (a), 9 (b) and 10 (a), 10 (b) is about 145 Ω as shown in Table 1 below. Yes, the input impedance in terms of the coplanar line side force is about 158 Ω.

[0057] [Table 1]

[0058] The characteristics shown in FIGS. 8 (a) to 10 (b) are the results when the wiring line 17 is manufactured with the following specifications.

Through-hole electrode 10 ··· Thickness φ θ. 3mm, length 1. Omm

Conductive connection member 12… Thickness φ θ. 15mm, length 1. Omm

[0059] Fig. 12 (a) to Fig. 14 (b) show the characteristics of an embodiment in which a coplanar line having the following specifications is connected to the wiring line 17 having the above characteristics.

[0060] That is, the coplanar line 9 has the following specifications. Note that the dimensions T, G, V, L, and H in the following specifications are as follows: L: Length of the coplanar line, W: Width dimension of the coplanar line, G: Ground facing the coplanar line Horizontal direction between electrodes T: Thickness of electrode (fixed at 20 / zm), H: Vertical distance between ground electrodes (fixed at 0.4 mm), C3: Through-hole electrode 10 And stray capacitance at the connection between the coplanar line 9 and C4: stray capacitance at the connection between the coplanar line and the antenna feed terminal. Specifically, L = 3.99 mm, W = 0.2 mm, G = 0.98 mm, C3 = 0.38 pF and C 4 = 0.50 pF. [0061] FIG. 12 (a) shows the pass characteristics of the above embodiment having the coplanar line and the wiring line designed as described above, and FIG.

[0062] As is clear from Figs. 12 (a) and (b), 2f = 11.6G for the center frequency f = 5.8GHz.

0 0

It can be seen that about 25 dB attenuation is secured at Hz and 3f = 17.4 GHz.

0

FIGS. 13A and 13B show the reflection characteristic SI 1 viewed from the RF circuit side and the reflection characteristic S 22 viewed from the antenna element side of the above embodiment. FIGS. 14A and 14B show impedance Smith charts obtained based on the reflection characteristics S11 and S22.

[0064] As is apparent from FIGS. 12 (a) and 12 (b), a large attenuation can be secured on the higher frequency side than the center frequency, and thus a low-pass filter having a sufficiently large out-of-band attenuation is realized. I can tell you.

[0065] FIGS. 15 (a) and 15 (b) show the pass characteristics of the coplanar line 9 alone in the above embodiment and the pass characteristics shown by enlarging the main part thereof. Also, the reflection characteristic S11 seen from the wiring line side of the coplanar line 9 and the reflection characteristic S22 seen from the antenna element side are shown in FIGS. 16 (a) and 16 (b). FIGS. 17 (a) and 17 (b) are Smith charts drawn based on the reflection characteristics Sl l and S22.

[0066] The impedance in the coplanar line 9 obtained from FIGS. 16 (a) to 17 (b) is as shown in Table 2 below.

[0067] [Table 2]

That is, the impedance on the wiring line side of the coplanar line 9 is about 132 Ω, and the input impedance on the antenna element side is about 95 Ω.

Therefore, in the present embodiment, the impedance of the coplanar line 9 is made lower than the impedance of the wiring line 17 side shown in Table 1 described above, thereby further reducing the impedance of the coplanar line 9 to the antenna element side. By making the input impedance on the wiring line side higher than the input impedance of the line, it is confirmed that a large attenuation is secured as described above. Karu. This is due to the effect that a low-pass filter is formed by the inductivity of the wiring line 17 and the capacitance of the coplanar line 9.

[0070] Next, in the coplanar line, L = 3.10 mm, W = 0.2 mm, G = l. OOmm, C3 = 0.66 pF, and C4 = 0.89 pF In the same manner, a high frequency module was constructed. Figure 18 (a) shows the pass characteristics in this case, and Fig. 18 (b) shows an enlarged view of the main parts of the pass characteristics. As is clear from Fig. 18 (a) and (b), 2f = 11.6 GHz

0

And at 3f = 17.4GHz, the attenuation is about 35dB, which is larger than the above experimental example.

0

It is powerful to be.

In this case, FIG. 19A shows the reflection characteristic S11 in which the RF circuit side force is also seen, and FIG. 19B shows the reflection characteristic S22 in which the antenna element side force is also seen. Figures 20 (a) and 20 (b) show impedance Smith charts for the reflection characteristics Sl l and S22 drawn based on Figs. 19 (a) and 19 (b), respectively.

[0072] FIG. 21 (a) shows the single passage characteristic of the coplanar line 9 in this second experimental example, and FIG. 22 (a) and 22 (b) show the reflection characteristic S11 as seen from the wiring line side of the coplanar line 9 and the reflection characteristic S22 as seen from the antenna element side. Further, FIGS. 23 (a) and 23 (b) are impedance Smith charts drawn based on the reflection characteristics S11 and S22 of the coplanar line alone.

[0073] When the impedance is obtained from FIGS. 22 (a) and 22 (b) and FIGS. 23 (a) and 23 (b), it is as shown in Table 3 below.

[0074] [Table 3]

That is, in the second experimental example, the input impedance on the wiring line side of the coplanar line portion is about 124.4 Ω, the input impedance on the antenna element side is about 58.6 Ω, and this impedance ratio Ζ / Ζ is 58. 6/124. 4 = 0. 471, the wiring line side

S22 S11

The impedance of is becoming very large.

[0076] In the second experimental example, the impedance of the wiring line is the same as that of the first experiment described above. Similar to the example, the input impedance on the RF circuit side is 145 Ω, and the input impedance on the coplanar line side is 158 Ω. Therefore, in the second experimental example, the impedance of the coplanar line is less than the impedance of the wiring line 17. Is also low.

[0077] As is clear from the first and second experimental examples, the impedance of the coplanar line is made lower than the impedance of the wiring line, and the input impedance 見 viewed from the wiring line side of the coplanar line is Input impedance seen from the antenna element side Ζ

By making Sll S22 higher, in other words, by making Ζ smaller than Ζ

S22 S11

It can be seen that out-of-band attenuation can be obtained and spurious can be effectively suppressed.

[0078] In this case, in the experimental example 2, compared with the experimental example 1, the impedance ratio Ζ / Ζ force,

S22 and S11, and accordingly, the attenuation is further increased. According to the experiments of the present inventor, a copy of the input impedance ζ as seen from the wiring line side of the coplanar line

S11

The above-mentioned input which is the ratio of the input impedance

S22

If the impedance ratio Ζ / Ζ is 0.63 or less, the out-of-band attenuation is more effectively suppressed.

S22 S11

It has been confirmed that That is, as shown in FIG. 24 and Table 4 below, when the impedance ratio is changed, the out-of-band attenuation changes as shown. On the other hand, the standard for the spurious emission strength is the standard value specified in ARIB STD-75: 2.5 W or less, 2.5, u W = 26.0206 dBm. Therefore, when the impedance it is 0.63 or less, an out-of-band attenuation of 27 dB or more can be obtained, so that the above standard can be satisfied. Therefore, since the filter for suppressing spurious can be deleted, the high-frequency module can be further reduced in size. Therefore, it can be seen that it is desirable to set the impedance ratio Z / Z to 0.63 or less.

S22 S11

[0079] [Table 4]

[0080] It should be noted that the Z and Z values are controlled by the length of the coplanar line.

Sll S22

This can be done by adjusting each value such as stray capacitance. That is, for example, Z / Z can be controlled by configuring the transmission line and controlling the above dimensions and area of the coplanar line 9 or the thickness of the conductor constituting the coplanar line 9.

S22 S11

. More specifically, the impedance ratio can be increased by increasing the stray capacitance by increasing the line length, and the impedance ratio can be decreased by increasing the stray capacitance by decreasing the line length. Can do. In other words, Z / Z can be used for various transmission line structures.

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By changing, it can be easily controlled. Of course, depending on the situation, it can be controlled by other parameters such as the width of the coplanar line and the distance to the ground electrode.

[0081] In the present invention, the high-frequency element is not limited to an antenna element, and an antenna matting element, switch element, power amplifier, low noise amplifier, transmitting RF or IC, receiving RF or IC, or the like may be used. Oh ,.

Claims

The scope of the claims

[1] An RF circuit section, a high-frequency element, and a line connecting the RF circuit section and the high-frequency element, and connecting the stray capacitance of the line force to a ground potential allows the line to be connected to a single path. Used as a filter! /

A first substrate;

The RF circuit portion provided on the first substrate;

A second substrate;

The high-frequency element provided on the second substrate;

The transmission line comprising the transmission line, one end connected to the high-frequency element and the transmission line, one end connected to the transmission line, and the other end connected to the RF circuit,

The transmission line is provided on the second substrate, the impedance of the transmission line is made lower than the impedance of the wiring line, and the input impedance viewed from the wiring line side of the transmission line is the high frequency of the transmission line. A high-frequency module characterized by being higher than the input impedance seen from the element side.

[2] The high frequency device according to claim 1, wherein a ratio of an input impedance viewed from the high frequency element side of the transmission line to an input impedance viewed from the wiring line side of the transmission line is 0.63 or less. module.

[3] The high frequency module according to claim 1 or 2, wherein an input impedance of the wiring line viewed from the RF circuit side force is set lower than an input impedance of the wiring line viewed from the transmission line side.

[4] The high frequency module according to any one of claims 1 to 3, wherein the transmission line is a coplanar line.

[5] The transmission line according to any one of claims 1 to 3, wherein the transmission line is a strip line provided in the second substrate, and a ground electrode is disposed above and below the strip line. High frequency module.

[6] The high-frequency module according to any one of claims 1 to 4, wherein the high-frequency element is mounted in the center of the main surface of the second substrate.

[7] The high-frequency element is mounted on a portion of the main surface of the second substrate that is shifted in central force, and one end of the transmission line is connected to the portion on which the high-frequency element is mounted. Item 7. The high-frequency module according to any one of items 1 to 6.

8. The high frequency module according to any one of claims 1 to 7, wherein the high frequency element is an antenna element.