JP4360045B2 - Multilayer directional coupler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stacked directional coupler, and more particularly to a stacked directional coupler used for wireless communication equipment such as a mobile phone.
[0002]
[Prior art]
A directional coupler using a transmission line having an electrical length corresponding to a quarter wavelength has been conventionally used in high-frequency equipment. A laminated directional coupler is also widely used in small wireless communication devices such as mobile phones because of its small size.
[0003]
By the way, in recent years, there has been proposed a dual-band mobile phone capable of making calls in two frequency bands with one mobile phone terminal. A multilayer directional coupler used in this dual-band mobile phone terminal is known from JP-A-11-261313. As shown in FIG. 6, this directional coupler includes dielectric sheets 2 b and 2 d provided with main lines 3 and 5 on the surface, a dielectric sheet 2 c provided with sub-lines 4 on the surface, and a ground electrode 6. , 7 are provided with dielectric sheets 2a, 2e and the like provided on the surface. The main lines 3 and 5 are formed so as to face the sub lines 4 with the sheets 2b and 2c interposed therebetween. Therefore, the main line 3 and the sub line 4 and the main line 5 and the sub line 4 are electromagnetically coupled to constitute a coupler.
[0004]
[Problems to be solved by the invention]
However, the conventional laminated directional coupler 1 has poor isolation between the main lines 3 and 5 because the two main lines 3 and 5 are electromagnetically coupled to the common part of the sub-line 4 respectively. There was a problem.
[0005]
The main line 3 is set to an electrical length corresponding to a quarter wavelength of one of the two used center frequencies, and the main line 5 corresponds to a quarter wavelength of the other used center frequency. Set to electrical length. That is, the main lines 3 and 5 are set to optimum electric lengths, and have different electric lengths. However, since the secondary line 4 is shared, the electrical length of the secondary line 4 is adjusted to the longer electrical length of the main lines 3 and 5. Accordingly, there is a problem in that the isolation characteristics and electromagnetic coupling characteristics cannot be individually optimized for each of the two frequency bands of the dual-band mobile phone terminal.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a stacked directional coupler that can optimize electrical characteristics independently for each frequency band and has excellent isolation between main lines.
[0007]
[Means and Actions for Solving the Problems]
In order to achieve the above object, a laminated directional coupler according to the present invention is provided.
(A) a main line through which high-frequency signals having different frequencies are transmitted;
(B) two or more coupled line portions that are electromagnetically coupled to the two or more main lines, respectively , and one sub-line having a via-hole conductor connecting the two or more coupled line portions ;
And the ground electrode facing the front Kifukusen path (c),
(D) comprising a dielectric layer disposed between the main line, the sub line, and the ground electrode,
(E) The main line, the sub line, the ground electrode, and the dielectric layer are stacked to form a stacked body, and the coupling line portion of the sub line is provided in the stacking direction of the stacked body. Juxtaposed across the dielectric layer ,
(F) An electrodeless portion where the ground electrode is not provided is formed around the via-hole conductor ,
It is characterized by.
Further, each of the two or more coupled line portions may be provided between the two or more main lines and the ground electrode in the stacking direction of the stacked body.
[0008]
With the above configuration, the sub-line is configured with a plurality of coupled line portions, and each of these coupled line portions is electromagnetically coupled to the main line independently. That is, since the plurality of main lines are electromagnetically coupled to different parts of the sub-lines, the isolation between the main lines is improved. Furthermore, the electrical length and the like can be set for each coupled line portion of the sub line.
[0009]
Before mentioned the laminated type directional coupler, interchanged main line and the sub-line, and two or more sub-line, may be provided and one of the main line having two or more binding line section.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a laminated directional coupler according to the present invention will be described below with reference to the accompanying drawings. In each embodiment, the same parts and the same parts are denoted by the same reference numerals.
[0011]
[First Embodiment, FIGS. 1 to 3]
As shown in FIG. 1, the laminated directional coupler 11 includes dielectric sheets 12d and 12h having main lines 14 and 15 provided on the surface thereof, and coupling line portions 13a and 13b of the sub line 13 provided on the surface thereof, respectively. The dielectric sheets 12e, 12g, and the dielectric sheets 12b, 12f, 12j having ground electrodes 18, 19, 20 provided on the surface thereof, respectively. As a material of the dielectric sheets 12a to 12j, a resin such as epoxy or a ceramic dielectric is used. In the first embodiment, as a material for the dielectric sheets 12a to 12j, a dielectric ceramic powder that is kneaded with a binder and then formed into a sheet shape is used. The sheet thickness of each dielectric sheet 12a-12j is set to a predetermined dimension. That is, the sheets 12b, 12d, 12g, and 12i are set thicker than the other sheets 12a, 12c, 12e, 12f, 12h, and 12j. At this time, the thickness of the sheets 12b, 12d, 12g, and 12i may be secured by stacking a plurality of sheets having the same sheet thickness as the other sheets 12a or the like, or secured by using one thick sheet. Also good.
[0012]
The main line 14 has a spiral shape, and one end of the main line 14 is electrically connected to the extraction electrode 16 through a via hole 25 provided in the sheet 12c. The main line 15 has a spiral shape, and one end of the main line 15 is electrically connected to the extraction electrode 17 through a via hole 25 provided in the sheet 12h. The main lines 14 and 15 each have an electrical length corresponding to a quarter wavelength of the used center frequency. The sub line 13 has spiral coupled line parts 13a and 13b. The coupled line portions 13a and 13b are electrically connected in series via via holes 25 provided in the sheets 12e and 12f, respectively.
[0013]
The shielding ground electrodes 18, 19, and 20 are provided on substantially the entire surfaces of the sheets 12b, 12f, and 12j, respectively. These shielding ground electrodes 18 to 20 are arranged at a predetermined distance from the coupled line portions 13a and 13b of the main lines 14 and 15 and the sub line 13 in consideration of the characteristics of the directional coupler. Is preferred. However, one of the ground electrodes 18 and 20 may not be provided. The main lines 14 and 15, the sub line 13, and the shielding electrodes 18 to 20 are formed by a method such as a sputtering method, a vapor deposition method, a printing method, and a photolithography method, and are made of a material such as Ag-Pd, Ag, Pd, or Cu. Consists of.
[0014]
The sheets 12a to 12j are stacked and integrally fired to form a rectangular laminate 30 as shown in FIG. Eight external electrodes 31 to 36, G1, and G2 are formed on the laminate 30. These external electrodes 31 to 36, G1, and G2 are formed by a method such as a sputtering method, a vapor deposition method, a coating method, and a printing method, and are made of a material such as Ag—Pd, Ag, Pd, Cu, or Cu alloy.
[0015]
External electrodes 31 and 32 formed on the front and back side surfaces of the laminate 30 are electrically connected to the extraction electrode 16 and the main line 14, respectively, and function as external terminals of the main line 14. The external electrodes 33 and 34 are electrically connected to the extraction electrode 17 and the main line 15, respectively, and function as external terminals of the main line 15. The external electrodes G1 and G2 are electrically connected to the ground electrodes 18 to 20 and function as ground terminals. The external electrodes 35 and 36 formed on the left and right end faces of the multilayer body 30 are electrically connected to the coupled line portions 13 a and 13 b of the sub line 13, respectively, and function as external terminals of the sub line 13. FIG. 3 shows an electrical equivalent circuit diagram of the laminated directional coupler 11.
[0016]
In the directional coupler 11 having the above configuration, the coupled line portion 13a of the sub line 13 and the main line 14 are disposed between the shield ground electrodes 18 and 19 to form a stripline structure. The coupled line portion 13b and the main line 15 are also disposed between the shield ground electrodes 19 and 20, and have a stripline structure. And the coupling line part 13a of the main line 14 and the subline 13 is formed so that it may oppose on both sides of the sheet | seat 12d. Therefore, the spiral pattern of the main line 14 and the spiral pattern of the coupled line portion 13a substantially overlap each other in plan view, and the coupler 1 is configured by electromagnetic coupling (line coupling) at the opposed portions. Similarly, the spiral pattern of the main line 15 and the spiral pattern of the coupled line portion 13b substantially overlap each other in plan view, and the coupler 2 is configured by electromagnetic coupling (line coupling) at the opposed portions.
[0017]
Here, when adjusting the electrical characteristics of the directional coupler 11, the thicknesses of the dielectric sheets 12d and 12g, the line widths or the number of turns of the coupling line portions 13a and 13b of the sub line 13 and the main lines 14 and 15 are changed. Thus, the electromagnetic coupling between the main line 14 and the coupled line portion 13a and the electromagnetic coupling between the main line 15 and the coupled line portion 13b are adjusted.
[0018]
Further, in the first embodiment, a shield ground electrode 19 is provided between the coupled line portions 13a and 13b to prevent electromagnetic coupling between the couplers 1 and 2. The shield ground electrode 19 has an electrodeless portion 19 a formed around the via hole 25.
[0019]
In this directional coupler 11, the sub-line 13 has two coupled line portions 13 a and 13 b, and these two coupled line portions 13 a and 13 b are electromagnetically coupled to the main lines 14 and 15 independently. Therefore, the isolation between the main lines 14 and 15 can be improved. Furthermore, since the electrical length can be set for each of the coupled line portions 13a and 13b in accordance with the main lines 14 and 15 having different electrical lengths, the isolation characteristics, the electromagnetic coupling characteristics, etc. can be individually set for each of the two used frequency bands. Can be optimized. Further, since the coupled line portions 13a and 13b of the sub-line 13 are juxtaposed with the dielectric sheets 12e and 12f sandwiched in the stacking direction of the laminate 30, the two coupled line portions 13a and 13b are disposed on the same dielectric sheet. The size of the directional coupler 11 can be reduced to about ½ compared to the case where the two are juxtaposed.
[0020]
Next, a case where this directional coupler 11 is used in a transmission circuit unit of a dual band mobile phone terminal will be described with reference to FIG. Usually, the transmission of a high frequency (microwave) signal does not simultaneously transmit signals corresponding to two systems to be used (for example, 900 MHz band and 1800 MHz band), and the two couplers 1 and 2 operate simultaneously. There is nothing.
[0021]
The high-frequency transmission signal transmitted from the modulation circuit unit is amplified by the transmission power amplifier 41, supplied to the antenna 43 through the directional coupler 11 and the branching filter 42, and radiated from the antenna 43 into the air. The One end of the sub line 13 of the directional coupler 11 is terminated with a resistor R, and the other end is electrically connected to the automatic gain control circuit 44. The sub line 13 couples the main line 14 (or 15) to a transmission signal transmitted from the transmission power amplifier 41 toward the branching filter 42, and outputs proportional to it (several tens to several minutes of the transmission signal). 1) is taken out and supplied to the automatic gain control circuit 44. The automatic gain control circuit 44 monitors the output extracted from the sub line 13 and controls the gain of the transmission power amplifier 41. Furthermore, if the directional coupler 11 is used, circuits such as the automatic gain control circuit 44 and the transmission power amplifier 41 can be shared, which is effective for high-density mounting.
[0022]
[Second Embodiment, FIGS. 4 and 5]
An eddy current is generated in the ground electrode facing the transmission line (main line or sub line) by the magnetic field of the transmission line. The loss due to this eddy current degrades the Q of the directional coupler. Therefore, in the second embodiment, a directional coupler capable of preventing the deterioration of Q due to this eddy current loss will be described.
[0023]
As shown in FIGS. 4 and 5, the stacked directional coupler 51 of the second embodiment is the same as the directional coupler 11 of the first embodiment except that the shielding ground electrode and the ground external electrode are omitted. It is the same thing. Therefore, the eddy current loss generated in the ground electrode due to the magnetic fields of the main lines 14 and 15 and the sub line 13 can be reduced. As a result, the Q of the directional coupler 51 is improved and insertion loss can be suppressed. The shield ground electrode may be formed only on one of the dielectric sheets 12b, 12f, or 12j.
[0024]
[Other Embodiments]
The laminated directional coupler according to the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist thereof. For example, in the directional couplers 11 and 51 of the first and second embodiments, the main line and the sub line are interchanged, and two or more sub lines and one main line having two or more coupled line parts You may use as a directional coupler provided with. Specifically, in the directional couplers 11 and 51 of the first and second embodiments, the spiral patterns 14 and 15 are used as sub-lines, and the spiral patterns 13a and 13b are used as the coupled line portions of the main lines, respectively. May be.
[0025]
Moreover, the shapes of the main line and the sub line are arbitrary, and may be meandering or linear in addition to the spiral shape. Further, the main line and the sub line do not necessarily have to be set to a length of ¼ wavelength, and the line width does not have to be set to the same dimension for all the lines. Furthermore, the number of couplers built in the laminated directional coupler according to the present invention is arbitrary two or more.
[0026]
Further, the main line and the sub line are not limited to a strip line structure disposed between two ground electrodes, but are a so-called microstrip line structure in which only one ground electrode is placed with a dielectric layer in between. May be. Further, the electromagnetic coupling between the main line and the sub line is not limited to the line coupling. When a plurality of spiral line patterns are connected in series via via holes to form a main line and a sub line having a multilayer structure, the main line and the sub line are coil-coupled.
[0027]
Moreover, although the said embodiment demonstrated the case of the individual product as an example, in the case of mass production, the mother board | substrate provided with the directional coupler for several pieces is manufactured, and it cuts out to desired size and is set as a product. be able to. Further, in the above-described embodiment, the dielectric sheets on which the conductors are formed are stacked and then fired integrally. However, the present invention is not necessarily limited to this. A sheet fired in advance may be used. Moreover, you may manufacture a directional coupler by the manufacturing method demonstrated below. A paste-like dielectric material is applied by means of printing or the like to form a dielectric layer, and then a paste-like conductor material is applied to the surface of the dielectric layer to form an arbitrary conductor. Next, a paste-like dielectric material is applied over the conductor. In this way, a directional coupler having a laminated structure can be obtained by successively applying in layers.
[0028]
【The invention's effect】
As is apparent from the above description, according to the present invention, the sub-line is constituted by a plurality of coupled line portions, and each of these coupled line portions is electromagnetically coupled independently to the main line. That is, since the plurality of main lines are electromagnetically coupled to different portions of the sub lines, the isolation between the main lines can be improved. Furthermore, the electrical length and the like can be set for each coupled line portion of the sub line. Therefore, the electrical characteristics can be individually optimized for each of the used frequency bands. Furthermore, since the coupled line portion of the sub line is juxtaposed with the dielectric layer sandwiched in the stacking direction of the laminate, the directionality is compared with the case where two coupled line portions are juxtaposed on the same dielectric layer. The size of the coupler can be reduced to about ½.
[0029]
Further, by omitting the ground electrode facing the transmission line of the main line and the sub line, the eddy current loss generated in the ground electrode due to the magnetic field of the transmission line can be reduced, and the Q of the directional coupler is improved. Insertion loss can be suppressed. Furthermore, in the laminated directional coupler, the degree of freedom in designing communication equipment is increased by including two or more sub-lines and one main line having two or more coupled line portions.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a first embodiment of a laminated directional coupler according to the present invention.
2 is an external perspective view of the stacked directional coupler shown in FIG. 1. FIG.
3 is an electrical block diagram showing a transmission circuit unit of a dual-band mobile phone terminal using the stacked directional coupler shown in FIG. 1. FIG.
FIG. 4 is an exploded perspective view showing a second embodiment of the laminated directional coupler according to the present invention.
5 is an external perspective view of the stacked directional coupler shown in FIG. 4. FIG.
FIG. 6 is an exploded perspective view showing a conventional laminated directional coupler.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11, 51 ... Laminated type directional coupler 12a-12j ... Dielectric sheet 13 ... Sub line 13a, 13b ... Coupling line part 14, 15 ... Main line 18-20 ... Ground electrode 30 ... Laminated body

Claims (4)

Two or more main lines for transmitting high-frequency signals of different frequencies;
Two or more coupled line portions that are electromagnetically coupled to the two or more main lines, respectively , and one sub-line having a via-hole conductor connecting the two or more coupled line portions ;
And the ground electrode facing the front Kifukusen path,
A dielectric layer disposed between the main line, the sub line, and the ground electrode,
The main line, the sub line, the ground electrode, and the dielectric layer are stacked to form a stacked body, and the coupling line portion of the sub line is provided with the ground electrode in the stacking direction of the stacked body. Juxtaposing the body layer ,
Around the via hole conductor is formed an electrodeless portion where the ground electrode is not provided ,
A laminated directional coupler characterized by the above. Each of the two or more coupled line portions is provided between the two or more main lines and the ground electrode in the stacking direction of the stacked body;
The laminated directional coupler according to claim 1. Two or more sub-lines that transmit high-frequency signals of different frequencies;
Two or more coupled line portions that are electromagnetically coupled to the two or more sub-lines, respectively , and one main line having via-hole conductors connecting the two or more coupled line portions ;
And a ground electrode opposed to the main line path,
A dielectric layer disposed between the main line, the sub line, and the ground electrode,
The main line, the sub line, the ground electrode, and the dielectric layer are stacked to form a stacked body, and the coupled line portion of the main line is provided with the ground electrode in the stacking direction of the stacked body. Juxtaposing the body layer ,
Around the via hole conductor is formed an electrodeless portion where the ground electrode is not provided ,
A laminated directional coupler characterized by the above. Each of the two or more coupled line portions is provided between the two or more sub-lines and the ground electrode in the stacking direction of the stacked body;
The laminated directional coupler according to claim 3.

Images