JP4473147B2 - Phase line and duplexer - Google Patents

Description

  The present invention relates to a phase line for impedance matching and a duplexer using the phase line.

  A duplexer is mainly used in a radio communication system such as a CDMA (Code Division Multiple Access) mobile phone. In a CDMA wireless system, transmission and reception are performed simultaneously using a single antenna, so a demultiplexer is required to separate the transmission signal and the reception signal and prevent the signals from affecting each other. (For example, refer to Patent Document 1). FIG. 5 shows a general configuration of a duplexer mounted on a mobile phone.

  As shown in FIG. 5, the duplexer is received by the antenna 4 and the transmission filter 1, which is a bandpass filter having a center frequency f <b> 1 that passes only a transmission signal from a transmission circuit (not shown) and supplies the signal to the antenna 4. The reception filter 2 is a band pass filter having a center frequency f2 (f1 ≠ f2) that passes only a predetermined reception signal among the high-frequency signals, and is provided between the antenna 4 and the input terminal of the reception filter 2. And a branching circuit 3 for impedance matching. The transmission circuit generates a high-frequency transmission signal based on the audio signal or data signal to be transmitted, and outputs it to the transmission filter 1. The reception circuit demodulates the reception signal output from the reception filter 2 and extracts an audio signal, a data signal, and the like.

  As the transmission filter 1 and the reception filter 2, a SAW (Surface Acoustic Wave) filter or a BAW (Bulk Acoustic Wave) filter using a piezoelectric thin film is used. The branching circuit 3 prevents characteristic deterioration due to mutual interference between the transmission filter 1 and the reception filter 2. A phase line having an electrical length of about λ / 4 (λ is the wavelength of an electromagnetic wave used in a mobile phone) is frequently used in the branching circuit 3. The phase line is formed of a strip line and is mounted on the ceramic package together with the transmission filter 1 and the reception filter 2.

  FIG. 6 is a cross-sectional view showing a configuration of a conventional phase line (strip line). The phase line is obtained by providing a signal conductor 103 in a dielectric 102 sandwiched between GND conductors 101. Since the characteristic impedance of the phase line is usually 50Ω, the dielectric constant and thickness of the dielectric 102 and the width of the signal conductor 103 are designed so that the characteristic impedance of the phase line is 50Ω.

  As mobile phones become smaller and thinner, duplexers are also required to be smaller and thinner. The element having the largest volume among the elements constituting the branching filter is the branching circuit 3. In order to operate the phase line as the branching circuit 3, it is necessary to set the electrical length of the phase line to λ / 4 as described above. For example, the quarter wavelength of the 800 MHz electromagnetic wave in vacuum is approximately 94 mm. If this electric length of 94 mm is to be realized by using the dielectric 102 having a relative dielectric constant of 7, a line length of 35 mm is required. In order to shorten the line length, it is sufficient to use the dielectric 102 having a large relative dielectric constant. However, if the relative dielectric constant is increased, the thickness of the dielectric 102 for setting the characteristic impedance to 50Ω is increased, and the thickness is reduced. Contrary to the request.

By reducing the width of the signal conductor 103, the characteristic impedance of the phase line can be set to 50Ω without changing the thickness of the dielectric 102. However, because the line width that can be processed by the signal conductor 103 is limited, Not practical. Further, when the distance between the phase lines is reduced and the area occupied by the phase line is reduced, the impedance is lowered due to the coupling between the lines, and the characteristic impedance is deviated from 50Ω. Moreover, although the area can be reduced by overlapping two phase lines shown in FIG. 6 on the top and bottom, there is a problem that the thickness of the phase line increases.
Thus, it has been proposed to reduce the size of the phase line by arranging three layers of signal conductors between the GND conductors (see, for example, Patent Document 2).

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
JP-A-10-126213 JP 2002-176337 A

According to the phase line disclosed in Patent Document 2, it is possible to reduce the size, but there is a problem that the insertion loss (insertion loss) is large.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a small-sized phase line with a small insertion loss and a duplexer using the phase line.

The phase line of the present invention has a plurality of signal conductors separated from each other by the dielectric and electrically connected in series inside a dielectric sandwiched between two layers of GND conductors. The signal conductors of the layers have the same shape in plan view, and the horizontal positions of the signal conductors of the plurality of layers are the same.
Further, in one configuration example of the phase line of the present invention, a plurality of unit structures each including the dielectric and the plurality of layers of signal conductors are stacked between the two layers of GND conductors, and each unit structure is interposed between the unit structures. The two layers of GND conductors are separated by another GND conductor, and signal conductors of each unit structure are electrically connected in series.
In one configuration example of the phase line of the present invention, the signal conductors of the plurality of layers are two layers.

The present invention also provides a transmission filter that passes only a transmission signal from a transmission circuit and supplies the signal to an antenna, and passes only a predetermined reception signal among high-frequency signals received by the antenna and supplies the reception circuit to the reception circuit In a duplexer comprising a receiving filter and an impedance matching phase line provided between the antenna and the input terminal of the receiving filter, the phase line is sandwiched between two layers of GND conductors. A plurality of signal conductors separated from each other by the dielectric and electrically connected in series are provided inside the dielectric, and the signal conductors of the plurality of layers have the same shape in plan view, and The position of the signal conductor in the horizontal direction is the same.
Further, in one configuration example of the duplexer of the present invention, the phase line is formed by laminating a plurality of unit structures composed of the dielectric and the plurality of signal conductors between the two GND conductors, Each unit structure is separated by a GND conductor different from the two layers of GND conductors, and signal conductors of each unit structure are electrically connected in series.
In one configuration example of the duplexer of the present invention, the signal conductors of the plurality of layers are two layers.

  According to the present invention, by providing a plurality of layers of signal conductors inside a dielectric sandwiched between two layers of GND conductors, a phase line can be used as compared with the conventional structure in which the signal conductors between the GND conductors are one layer. The duplexer using the phase line can be miniaturized. Further, by making the signal conductors of the plurality of layers have the same shape in plan view and making the positions in the horizontal direction of the signal conductors of the plurality of layers the same, an increase in insertion loss due to the phase line can be suppressed. Further, in the present invention, the line length can be increased without reducing the horizontal distance between the lines, so that impedance reduction due to coupling between lines can be avoided. In addition, since the distance between the lines is large, a large number of via holes can be formed between the lines, so that an unnecessary inductance component between the two GND conductors can be reduced. Furthermore, in the present invention, by making the signal conductors of the plurality of layers have the same shape in plan view, it is possible to obtain an effect that the formation of each signal conductor layer is facilitated when the phase line is manufactured.

  Further, in the present invention, the line length per unit structure can be shortened by laminating a plurality of unit structures composed of a dielectric and a plurality of layers of signal conductors between two layers of GND conductors. Can be significantly reduced.

  In the present invention, the characteristic impedance of the phase line can be easily adjusted by using two signal conductors provided inside the dielectric sandwiched between two layers of GND conductors.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A is a plan view showing a schematic configuration of a duplexer package (hereinafter referred to as PKG) according to a first embodiment of the present invention, and FIG. 1B is a diagram of FIG. It is an AA line sectional view of a waver. Also in the present embodiment, the configuration as a duplexer is as shown in FIG.

FIG. 2A shows a perspective view of the GND conductor 11a of the duplexer in FIG. 1A from above, FIG. 2B shows a perspective view of the signal conductor 13a from above, and shows the signal conductor 13b. FIG. 2C shows a view seen through from above, and FIG. 2D shows a view seen through the GND conductor 11b from above.
The surface shown in FIG. 1A is a chip die-bonding surface, and the transmitting filter 1 and the receiving filter 2 are mounted on the chip die-bonding surface, and suitable for the pads 15 and 16 and other pads by wires or bumps (not shown). Connected to.

  The phase line (demultiplexing circuit 3) used in the duplexer of the present embodiment is separated from each other by the dielectric 12 inside the dielectric 12 sandwiched between the two layers of the GND conductors 11a and 11b, and is electrically The signal conductors 13a and 13b connected in series to each other are provided, the signal conductors 13a and 13b in the plurality of layers have the same shape in plan view, and the horizontal direction of the signal conductors 13a and 13b (direction parallel to the paper surface in FIG. 2) ) In the same position. In FIG. 1, 14 is a dielectric formed on the GND conductor 11a, and 15 and 16 are chip connection pads formed on the dielectric 14 and made of a conductor.

  As shown in FIGS. 1B, 2B, and 2C, one end of each of the signal conductors 13a and 13b is connected to each other by a via hole 17, and the other end of the signal conductor 13a is padded by a via hole 18. 15 and the other end of the signal conductor 13 b is connected to the pad 16 by a via hole 19. The pad 15 is connected to an input terminal of the reception filter 2, and the pad 16 is connected to an antenna (not shown) and an output terminal of the transmission filter 1. The GND conductors 11 a and 11 b are connected to each other by a via hole 20.

  In the duplexer PKG as described above, the layers from the GND conductor 11b to the pads 15 and 16 are sequentially stacked and then fired, and then the transmitting filter 1 and the receiving filter 2 are mounted on the chip die bond surface. Is produced.

As the dielectrics 12 and 14 serving as the base material of the PKG, a low-temperature fired ceramic (LTCC) having a relative dielectric constant of 9.6 is used, and a conductor material constituting the GND conductors 11a and 11b, the signal conductors 13a and 13b, and the pads 15 and 16 Cu was used.
In this embodiment, an 800 MHz band CDMA duplexer is assumed, and the reference frequency for defining the electrical length of the phase line is 880 MHz. The thickness t1 of the dielectric 12 between the GND conductor 11a and the signal conductor 13a, the thickness t2 of the dielectric 12 between the signal conductors 13a and 13b, so that the characteristic impedance of the phase line is 50Ω. The thickness t3 of the dielectric 12 between the signal conductor 13b and the GND conductor 11b was 150 μm, and the width of the signal conductors 13a and 13b was 75 μm.

  In the present embodiment, considering that the relative permittivity of the dielectric 12 is 9.6, the line length (total length of the signal conductors 13a and 13b) is set so that the electrical length is λ / 4. It is set to 27.5 mm. Further, in order to prevent coupling between the lines, the horizontal distances (D in FIGS. 2B and 2C) between the lines of the signal conductors 13a and 13b are arranged sufficiently separated.

  The inventor has confirmed through simulation that it is difficult to adjust the characteristic impedance of the phase line when the signal conductor has three layers as disclosed in Patent Document 2. For this reason, in the phase line disclosed in Patent Document 2, the characteristic impedance is adjusted by changing the shape of the signal conductor for each layer. However, if the shape of the signal conductor is changed for each layer, there is a problem that insertion loss (insertion loss) due to the phase line increases.

  Therefore, in the present embodiment, the signal conductors in the plurality of layers have the same shape in plan view, and the horizontal positions of the signal conductors in the plurality of layers are the same. Thereby, in this Embodiment, the increase in insertion loss can be suppressed. In this embodiment, the signal conductor has two layers 13a and 13b. It was confirmed by simulation that it is easy to adjust the characteristic impedance of the phase line to 50Ω by using two signal conductors. Parameters related to the characteristic impedance of the phase line are the relative permittivity of the dielectrics 12, 14, the thickness t1, t2, t3 of the permittivity 12, the width of the signal conductors 13a, 13b, and the signal conductors 13a, 13b. And the line length.

  In this embodiment, by providing two layers of signal conductors inside a dielectric sandwiched between two layers of GND conductors, the structure is almost the same as that of the conventional structure in which the signal conductor between the GND conductors is one layer. Using a dielectric having a thickness, a double line length can be formed in the same area. In other words, in the conventional structure in which the signal conductor between the GND conductors is a single layer, the configuration shown in FIG. 6 is laminated as shown in FIG. There is a need.

  In FIG. 3, 101a, 101b and 101c are GND conductors, 102a, 102b and 104 are dielectrics, 103a and 103b are signal conductors, 105 and 106 are pads for chip connection, and 107 is one end of signal conductors 103a and 103b. 108 is a via hole that connects the other end of the signal conductor 103a and the pad 105, 109 is a via hole that connects the other end of the signal conductor 103b and the pad 106, and 120 is a connection between the GND conductors 101a, 101b, and 101c. It is a via hole. Comparing FIG. 1B and FIG. 3, the thickness from the top surface of the dielectric 14 to the GND conductor 11b in FIG. 1B is the same as the thickness from the top surface of the dielectric 104 to the GND conductor 101b in FIG. It is almost the same. Therefore, in this embodiment, the phase line can be reduced in size as compared with the conventional structure in which the signal conductor between the GND conductors is a single layer, and the duplexer using the phase line can be reduced in size. .

  In the present embodiment, the signal conductors in the plurality of layers have the same shape in plan view (precisely, since the positions of the via holes 18 and 19 are different), and the horizontal positions of the signal conductors in the plurality of layers are the same. By doing so, an increase in insertion loss can be suppressed as compared with the phase line disclosed in Patent Document 2, and the characteristic impedance of the phase line can be easily adjusted by using two signal conductors. be able to. In the present embodiment, the line length can be increased without reducing the horizontal distance D between the lines, so that impedance reduction due to coupling between lines can be avoided. In addition, since the distance D between the lines is large, a large number of via holes 20 can be formed between the lines, so that unnecessary inductance components between the GND conductors 11a and 11b can be reduced. Furthermore, in the present embodiment, by making the signal conductors of the plurality of layers have the same shape in plan view, it is possible to obtain an effect that each signal conductor layer can be easily formed when the phase line is manufactured.

  In this embodiment, LTCC is used as the base material (dielectric bodies 12 and 14) of the PKG incorporating the phase line. However, the present invention is not limited to this, and alumina or resin may be used. Further, although Cu is used as a conductor material constituting the GND conductors 11a and 11b, the signal conductors 13a and 13b, and the pads 15 and 16, tungsten, Ag, or the like may be used. These conductors may be subjected to a surface treatment such as NiAu plating for preventing oxidation. Further, the thickness of the dielectric 12 and the signal conductors 13a and 13b, the width of the signal conductors 13a and 13b, the line length, etc. may be set according to the relative dielectric constant of the base material used, the frequency used and the required characteristics. It is not limited to the value of.

[Second Embodiment]
FIG. 4 is a sectional view showing a schematic configuration of the PKG of the duplexer according to the second embodiment of the present invention. The same configurations as those in FIGS. 1 and 2 are denoted by the same reference numerals. A plurality of unit structures composed of the dielectric and the plurality of layers of signal conductors described in the first embodiment may be stacked between the GND conductors 11a and 11b. In the example of FIG. 4, two unit structures are stacked.

  The unit structure composed of the dielectric 12a and the signal conductors 13a and 13b and the unit structure composed of the dielectric 12b and the signal conductors 13c and 13d are separated by the GND conductor 11c. Similarly to the first embodiment, one end of each of the signal conductors 13 a and 13 b is connected to each other by a via hole 17, and one end of each of the signal conductors 13 c and 13 d is connected to each other by a via hole 21. Although not shown in FIG. 4, the other end of the signal conductor 13b and the other end of the signal conductor 13c, the other end of the signal conductor 13a and the pad 15, and the other end of the signal conductor 13d and the pad 16 are provided. The GND conductors 11a, 11b, and 11c are connected to each other by via holes (not shown).

Thereby, in this Embodiment, since the line length per unit structure can be shortened instead of thickening PKG, the area of PKG can be reduced significantly.
The signal conductors 13a and 13b (or 13c and 13d) in one unit structure need to have the same horizontal position, but the signal conductors in the horizontal direction are different between different unit structures. May be off.
In the first and second embodiments, the GND conductor of each layer is configured by a single plate. However, the present invention is not limited to this, and the GND conductor of each layer may be divided into a plurality of parts. . If a plurality of GND conductors in the same layer are connected to each other externally, the configuration is equivalent to that of a single plate.

  The present invention can be applied to a phase line for impedance matching and a duplexer using the phase line.

1A and 1B are a plan view and a cross-sectional view showing a schematic configuration of a duplexer package according to a first embodiment of the present invention. FIG. 1A is a perspective view of the upper layer GND conductor of FIG. 1 from above, FIG. 2B is a perspective view of the upper signal conductor, FIG. 1C is a perspective view of the lower signal conductor from above, and FIG. It is the figure (D) which saw through the GND conductor of the lower layer from the top. It is sectional drawing when the signal conductor between GND conductors implement | achieves the phase line of the same characteristic as the phase line of FIG. 1 by the structure of one layer. It is sectional drawing which shows schematic structure of the package of the duplexer used as the 2nd Embodiment of this invention. It is a block diagram which shows the general structure of a splitter. It is sectional drawing which shows the structure of the conventional phase track.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transmission filter, 2 ... Reception filter, 3 ... Demultiplexing circuit, 11a, 11b, 11c ... GND conductor, 12, 12a, 12b, 14 ... Dielectric, 13a, 13b, 13c, 13d ... Signal conductor, 15 , 16 ... pads, 17, 18, 19, 20, 21 ... via holes.

Claims (6)

In a dielectric sandwiched between two layers of GND conductors, a plurality of signal conductors separated from each other by the dielectric and electrically connected in series,
The phase line, wherein the signal conductors of the plurality of layers have the same shape in plan view, and the horizontal positions of the signal conductors of the plurality of layers are the same. The phase line according to claim 1,
A plurality of unit structures composed of the dielectric and the plurality of layers of signal conductors are stacked between the two layers of GND conductors, and each unit structure is separated by a GND conductor different from the two layers of GND conductors. A phase line characterized in that the signal conductors of each unit structure are separated and electrically connected in series. In the phase line according to claim 1 or 2,
2. The phase line according to claim 1, wherein the signal conductors of the plurality of layers are two layers. A transmission filter that passes only a transmission signal from the transmission circuit and supplies the antenna to the antenna; a reception filter that passes only a predetermined reception signal among the high-frequency signals received by the antenna and supplies the reception circuit; and In the duplexer consisting of an impedance matching phase line provided between the antenna and the input terminal of the reception filter,
The phase line includes a plurality of signal conductors separated from each other by the dielectric and electrically connected in series inside a dielectric sandwiched between two layers of GND conductors. A duplexer, wherein the signal conductors have the same shape in plan view, and the signal conductors in the plurality of layers have the same horizontal position. The duplexer according to claim 4, wherein
The phase line is formed by laminating a plurality of unit structures composed of the dielectric and the signal conductors of the plurality of layers between the two layers of GND conductors, and between the unit structures, the two layers of GND conductors. A duplexer that is separated by another GND conductor and in which the signal conductors of each unit structure are electrically connected in series. The duplexer according to claim 4 or 5,
The duplexer is characterized in that the signal conductors of the plurality of layers are two layers.

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