JP5622781B2 - Directional coupler and wireless communication device - Google Patents

Description

  The present invention relates to a directional coupler and a wireless communication apparatus, and more particularly to a technique for realizing a directional coupler that can be used in a wide frequency band.

  A directional coupler (Directional Coupler / hereinafter simply referred to as “coupler”) that can extract a part of electric power propagating on a transmission line is transmitted by various wireless communication devices such as mobile phones and wireless LAN communication devices. It is an indispensable part in constructing a circuit.

  For example, the coupler constitutes adjusting means for controlling the transmission signal level to be constant, and this adjusting means includes a power amplifier (hereinafter referred to as “PA”) capable of controlling the gain and the transmission signal level. A coupler for detection and an automatic output control circuit (hereinafter referred to as “APC circuit”) are provided. The input transmission signal is amplified by the PA and then output through the coupler. The coupler outputs a monitor signal having a level corresponding to the level of the transmission signal output from the PA to the APC circuit. The APC circuit controls the gain of the PA so that the output of the PA becomes constant according to the level of the monitor signal (that is, the level of the transmission signal). The transmission output is stabilized by such feedback control of the PA.

  The coupler has a main line and a sub line arranged close to each other so as to be electromagnetically coupled. The main line for transmitting a transmission signal has an input port at one end and an output port at the other end. The sub-line for detecting the level of each has a coupling port at one end and an isolation port at the other end. A part of the transmission signal transmitted through the main line is taken out by the sub line, and is output to the APC circuit as a monitor signal through the coupling port.

  On the other hand, since communication frequency bands of mobile terminals typified by mobile phones and smartphones differ depending on countries and regions, communication devices that can use a plurality of frequency bands have been provided in recent years to flexibly cope with these frequency situations. Yes. For example, there are a dual band method that can use two frequency bands, a triple band method that can use three frequency bands, and a quad band method that can use four frequency bands.

  Specific frequency bands include, for example, one for a plurality of frequency bands such as GSM (Global System for Mobile Communications / registered trademark) 800, DCS (Digital Communication System), PCS (Personal Communication System), LTE (Long Term Evolution), etc. In order to be compatible with components, it is necessary to realize a coupler capable of obtaining stable characteristics over a wide band ranging from 700 to 2.7 GHz.

  Further, the following patent document discloses a technique for increasing the bandwidth of a coupler to cope with a plurality of communication channels.

JP 2007-194870 (Patent No. 4599302)

  By the way, the degree of coupling, which is the ratio of the power propagated through the main line as the transmission signal and the power taken out to the coupling port through the sub line, realizes highly accurate control of the transmission power (accurate feedback control of PA). It is desirable that the frequency characteristics be flat. In general, if the length of the main line and the sub line is set to about λ / 4 (quarter wavelength) of the used frequency band, the degree of coupling is flat in the frequency band. Can be obtained.

  However, the λ / 4 of the quasi-microwave band mainly used in mobile wireless devices such as mobile phones is several centimeters, and this is used as a coupler for mobile wireless devices such as mobile phones that need to be light and thin. Providing a long coupled line is difficult in terms of size. In addition, when a long coupled line of several centimeters or more is used, insertion loss increases, which causes an unfavorable situation for mobile radio equipment that shortens battery life. For this reason, a coupler with a coupling line shorter than λ / 4 in the operating frequency band is generally used, but the characteristics of such a coupling line vary depending on the frequency, and the degree of coupling tends to increase as the frequency increases. There is.

  Therefore, conventionally, when configuring a communication apparatus having a wide use frequency band as described above, it is necessary to provide a plurality of couplers. FIG. 34 is a block diagram showing an example of a transmission / reception unit of a mobile phone that can use a plurality of frequency bands. As shown in this figure, a conventional multiband mobile phone is provided corresponding to the use frequency band. The transmission circuits 301 and 401 are provided with couplers 311 and 411, respectively. In the figure, reference numeral 101 denotes an antenna, and 102 denotes a switch that distributes radio waves received through the antenna 101 to the reception circuits 103 and 104 and sends out transmission signals input from the transmission circuits 301 and 401 to the antenna 101, respectively. The switch 102 is configured by combining, for example, a diplexer or a high frequency switch.

  On the other hand, if a common coupler (for example, one) can be used in such a multiband communication device, the number of parts in the transmission circuit can be reduced, and the manufacturing cost of the device can be reduced. . In addition, the mobile communication device can be further reduced in size. Further, flattening the coupling degree of the coupler is preferable in terms of performing control of transmission power more easily and with less detection error.

  On the other hand, the invention described in the above-mentioned patent document is intended to increase the bandwidth of the coupler. However, in the present invention, circuit elements such as a capacitor serving as a low-pass filter are added to both ends of the sub-line, so that the number of parts (elements) constituting the coupler is increased and a plurality of circuit elements to be added are set. There is a problem that adjustment is complicated and difficult.

  Accordingly, an object of the present invention is to realize a small and low-profile coupler having good characteristics over a wide band with a simpler structure.

  In order to solve the problems and achieve the object, a coupler (directional coupler) according to the present invention includes a main line capable of transmitting a high-frequency signal, an input port for inputting the high-frequency signal to the main line, and the main An output port for outputting the high-frequency signal from a line; a sub-line for extracting a part of the high-frequency signal by electromagnetic coupling with the main line; a coupling port provided at one end of the sub-line; A coupler provided on a laminated substrate having a plurality of conductor layers laminated via an insulating layer with an isolation port provided at the other end of the sub line, wherein the sub line is longer than the main line, The main line is disposed on the first conductor layer of the multilayer substrate, and a first sub line portion that is a part of the sub line is disposed on the second conductor layer below the first conductor layer. One end of the line portion is connected to the coupling port and the Connected to one of the isolation ports, a second sub-line portion that is another part of the sub-line is disposed on the third conductor layer above the first conductor layer, and the second sub-line portion One end is connected to the other of the coupling port and the isolation port, and the other end of the first sub-line and the other end of the second sub-line are connected by an interlayer connection conductor (for example, via hole) When a line portion that is electrically connected and performs electromagnetic field coupling between the main line and the sub-line is referred to as a “coupled portion”, and a line portion that does not perform the electromagnetic field coupling is referred to as a “non-coupled portion”, At least a part of the line and a part of the first subline part are arranged so as to be close to each other, and at least a part of the main line and a part of the second subline part are close to each other By arranging the main line, the first A coupling portion is formed at each of the one end portion of the line portion and the one end portion of the second sub-line portion, and the sub-portion extends between the coupling portion of the first sub-line portion and the coupling portion of the second sub-line portion. The middle part of the line was defined as a non-coupled part.

  Further, in such a coupler, as a preferable aspect for forming the coupling portion, at least a part of the main line, a part of the first sub-line part, and a part of the second sub-line part are seen from a plane. It arrange | positions so that it may overlap sometimes, and, thereby, the said coupling | bond part is each made into the main line, the one end part of a 1st subline part, and the one end part of a 2nd subline part.

  In the coupler of the present invention, the sub line is divided into two upper and lower conductor layers with the main line as the center, and both ends of the sub line, that is, one end of the first sub line part disposed below the main line. And the main line and the sub-line are electromagnetically coupled so that the main line is sandwiched between one end of the second sub-line part disposed above the main line. The sub-line can be sufficiently long and the length of the sub-line can be increased. By adjusting the length of the sub-line, the coupling curve (frequency characteristic curve of the coupling degree) can be flattened. A coupler that can be used in a wide frequency band can be realized.

  In particular, as a preferred aspect of the present invention, when the wavelength corresponding to the set frequency higher than the lower end frequency of the used frequency band is λ and n is a positive integer, the sub-line is substantially {(λ / 4) Xn}. According to such an aspect, (1) higher frequency than the upper end frequency of the used frequency band, or (2) higher than the lower end frequency of the used frequency band and less than or equal to the upper end frequency of the used frequency band (that is, excluding the lower end frequency) By forming an attenuation pole due to resonance at a predetermined frequency position (set frequency) within the frequency band), the frequency fluctuation of the coupling degree (the tendency to increase as the frequency increases) is suppressed, and the coupling degree can be achieved over a wide band. A coupler having good flat characteristics can be realized.

  In the coupler of the present invention, it is preferable that the length of the first sub line portion and the length of the second sub line portion are substantially equal. Even if the length of the sub-line becomes long, the sub-line is divided into two layers with good balance in half, so that the sub-line is efficiently arranged in the laminated substrate, and the small size and low profile with good characteristics are achieved. This is to realize.

  In the coupler of the present invention, the ground electrode (hereinafter referred to as “intermediate ground”) is interposed between the non-coupled portion of the first sub-line portion and the non-coupled portion of the second sub-line portion in the stacking direction of the multilayer substrate. May be provided). According to such a structure, it is possible to prevent interference between the sub-line portions arranged above and below. The intermediate ground is preferably provided in the same conductor layer (first conductor layer) as the main line from the viewpoint of reducing the number of laminated layers and reducing the height of the coupler.

  As for the coupling part, the main line has the same function as the intermediate ground. That is, in the present invention, since the main line is interposed between the coupling part of the first sub-line part and the coupling part of the second sub-line part, the main line performs coupling with the sub-line and at the same time This also serves to block interference between the sub-line portions.

  In the present invention, a ground electrode (hereinafter referred to as “upper ground”) may be further provided above the third conductor layer so as to cover the uncoupled portion of the second sub line portion. Similarly, a ground electrode (hereinafter referred to as “lower ground”) may be provided below the second conductor layer so as to cover the uncoupled portion of the first sub-line portion.

  If the ground electrodes are provided on the upper and lower surfaces of the coupler main body portion (from the first conductor layer to the third conductor layer) in which the main line and the sub line are arranged in this way, when the coupler is mounted, other mounting parts, etc. The expected good characteristics can be obtained even after mounting. The upper ground and the lower ground overlap with the coupling portion of the main line, the coupling portion of the first sub-line portion, and the coupling portion of the second sub-line portion when viewed from a plane in order to avoid the influence on the coupling portion. It is preferable to arrange so as not to occur.

  Further, the upper ground and the lower ground not only have the above-described function of eliminating the influence of surroundings after mounting, but also a function of adjusting the degree of coupling. Specifically, in the present invention, in particular, in an aspect in which the sub-line has a length of (λ / 4) × n, the sub-line is external (surrounding) using electric power transmitted in the sub-line as electromagnetic waves. It is thought that it also functions as an antenna that radiates to). On the other hand, the upper ground and the lower ground arranged so as to cover the sub line serve to suppress the radiation from the sub line. Therefore, if the distance between the ground and the sub-line (the distance between the upper ground and the second sub-line part in the stacking direction or the distance between the lower ground and the first sub-line part) is adjusted, the radiation is emitted from the sub-line. The amount of electric power can be changed, and the degree of coupling can be adjusted. For example, in the third embodiment to be described later, by reducing the distance between the upper ground and the second sub line portion from the first embodiment, the power radiated from the sub line to the outside is suppressed and the attenuation of the coupling degree is adjusted. did.

  Typically, the uncoupled portion of the first subline portion and the uncoupled portion of the second subline portion are each formed in a spiral shape so as to draw a spiral. This is because the sub-line longer than the main line is arranged in the laminated substrate with good space efficiency.

  In the coupler of the present invention, as a preferred arrangement form of the main line and the sub line, when viewed from the plane, the main line coupling part, the first sub line part coupling part and the second sub line part coupling part are Arranged along one side edge of the multilayer substrate, the interlayer connection conductor is arranged at the center of the multilayer substrate, and the uncoupled portion of the first sub-line portion is connected to the multilayer substrate from the one side edge of the multilayer substrate. It is formed in a spiral shape so as to draw a spiral toward the center, and the uncoupled portion of the second sub line portion is directed from the center portion of the multilayer substrate toward one side edge of the multilayer substrate and the spiral of the first sub line portion. Form a spiral to draw a spiral in the same rotational direction.

  According to such an aspect, in addition to being able to arrange the main and sub lines efficiently, the transmission directions of the signals respectively flowing through the first sub line part and the second sub line part, which are arranged so as to overlap the upper and lower layers, are the same direction. Therefore, it is possible to prevent a situation in which the two sub-line portions interfere with each other and interfere with each other.

  Further, for the first sub-line portion and the second sub-line portion, the line widths of these non-coupled portions may be made smaller than the line width of the coupled portions. In the present invention, the uncoupled portion of the sub-line is longer than the coupled portion.However, if the coupled portion has a large line width and the uncoupled portion is thin in this way, sufficient coupling with the main line is achieved. A long sub-line (non-coupled portion) can be accommodated in a small area while ensuring.

  A radio communication apparatus according to the present invention is capable of generating transmission signals of two or more frequency bands, and includes a power amplifier that amplifies these transmission signals and an automatic output control circuit that controls the output of the power amplifier. A circuit, a reception circuit capable of processing a reception signal of the two or more frequency bands, an antenna that transmits and receives the transmission signal and the reception signal, and the antenna is connected between the transmission circuit and the reception circuit, A switch for transmitting a reception signal received through the antenna to the reception circuit and a transmission signal output from the transmission circuit to the antenna, and detecting a level of the transmission signal output from the power amplifier And a coupler for outputting the detection signal to the automatic output control circuit, and an output of the power amplifier based on the detection signal input from the coupler A radio communication apparatus for controlling, using any of the coupler according to the present invention as the coupler, in which the coupler is connected between the switch and the antenna.

  As described above, the conventional multiband wireless communication apparatus has to include a coupler for each frequency band. However, according to the coupler of the present invention, the degree of coupling can be flattened in a wide band. As described above, the number of components can be reduced to one (common to a plurality of use frequency bands), the number of components can be reduced, the manufacturing cost can be reduced, and the communication device can be downsized. I can do it.

  The wireless communication device referred to in the present invention is typically a mobile terminal device such as a mobile phone, a smartphone, a PDA (Personal Digital Assistants) or a tablet computer having a wireless communication function, but is not limited thereto. In addition, various communication devices capable of wireless communication, such as a wireless LAN communication device and a Bluetooth (registered trademark) standard communication device, are included.

  According to the present invention, it is possible to realize a small and low-profile coupler having a good characteristic over a wide band with a simple structure without adding circuit elements.

  Other objects, features, and advantages of the present invention will become apparent from the following description of embodiments of the present invention described with reference to the drawings. In addition, in each figure, the same code | symbol shows the same or an equivalent part.

FIG. 1 is a circuit diagram conceptually showing the coupler according to the first embodiment of the present invention. FIG. 2A is a plan view showing a first layer (conductor layer) of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2B is a plan view showing a first insulating layer of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2C is a plan view showing a second layer (conductor layer) of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2D is a plan view showing a second insulating layer of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2E is a plan view showing a third layer (conductor layer) of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2F is a plan view showing a third insulating layer of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2G is a plan view showing a fourth layer (conductor layer) of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2H is a plan view showing a fourth insulating layer of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2I is a plan view showing a fifth layer (conductor layer) of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2J is a plan view showing a fifth insulating layer of the multilayer substrate constituting the coupler according to the first embodiment. FIG. 2K is a plan view showing a sixth layer (conductor layer) of the multilayer substrate constituting the coupler according to the first embodiment (the back side of the substrate is shown in a transparent state). FIG. 3 is a diagram showing frequency characteristics of the coupling degree of the coupler according to the first embodiment. FIG. 4 is a diagram showing frequency characteristics of isolation of the coupler according to the first embodiment. FIG. 5 is a diagram showing the directional frequency characteristics of the coupler according to the first embodiment. FIG. 6 is a diagram showing frequency characteristics of insertion loss of the coupler according to the first embodiment. FIG. 7 is a diagram showing frequency characteristics of VSWR (Voltage Standing Wave Ratio) at the input port of the coupler according to the first embodiment. FIG. 8 is a diagram showing VSWR (frequency characteristics of VSWR viewed from the coupling port) of the sub-line of the coupler according to the first embodiment. FIG. 9A is a plan view showing a first layer (conductor layer) of the multilayer substrate constituting the coupler according to the second embodiment of the present invention. FIG. 9B is a plan view showing a first insulating layer of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9C is a plan view showing a second layer (conductor layer) of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9D is a plan view showing a second insulating layer of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9E is a plan view showing a third layer (conductor layer) of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9F is a plan view showing a third insulating layer of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9G is a plan view showing a fourth layer (conductor layer) of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9H is a plan view showing a fourth insulating layer of the multilayer substrate constituting the coupler according to the second embodiment. FIG. 9I is a plan view showing the fifth layer (conductor layer) of the multilayer substrate constituting the coupler according to the second embodiment (the back side of the substrate is shown in a transparent state). FIG. 10 is a diagram showing frequency characteristics of the coupling degree of the coupler according to the second embodiment. FIG. 11 is a diagram showing the frequency characteristics of isolation of the coupler according to the second embodiment. FIG. 12 is a diagram showing the directional frequency characteristics of the coupler according to the second embodiment. FIG. 13 is a diagram showing frequency characteristics of insertion loss of the coupler according to the second embodiment. FIG. 14 is a diagram showing the frequency characteristics of VSWR at the input port of the coupler according to the second embodiment. FIG. 15 is a diagram showing VSWR (frequency characteristics of VSWR viewed from the coupling port) of the sub-line of the coupler according to the second embodiment. FIG. 16 is a diagram showing the frequency characteristics of the coupling degree of the coupler according to the third embodiment of the present invention. FIG. 17 is a diagram showing the frequency characteristics of the insertion loss of the coupler according to the third embodiment. FIG. 18 is a diagram showing the frequency characteristics of VSWR at the input port of the coupler according to the third embodiment. FIG. 19 is a diagram showing VSWR (frequency characteristics of VSWR viewed from the coupling port) of the sub-line of the coupler according to the third embodiment. FIG. 20A is a plan view showing a first layer (conductor layer) of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20B is a plan view showing a first insulating layer of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20C is a plan view showing a second layer (conductor layer) of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20D is a plan view showing a second insulating layer of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20E is a plan view showing a third layer (conductor layer) of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20F is a plan view showing a third insulating layer of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20G is a plan view showing a fourth layer (conductor layer) of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20H is a plan view showing a fourth insulating layer of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20I is a plan view showing a fifth layer (conductor layer) of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20J is a plan view showing a fifth insulating layer of the multilayer substrate constituting the coupler according to the fourth embodiment. FIG. 20K is a plan view showing the sixth layer (conductor layer) of the multilayer substrate constituting the coupler according to the fourth embodiment (the back side of the substrate is shown in a transparent state). FIG. 21 is a diagram showing frequency characteristics of the coupling degree of the coupler according to the fourth embodiment. FIG. 22 is a diagram showing isolation frequency characteristics of the coupler according to the fourth embodiment. FIG. 23 is a diagram showing the directional frequency characteristics of the coupler according to the fourth embodiment. FIG. 24 is a diagram showing frequency characteristics of insertion loss of the coupler according to the fourth embodiment. FIG. 25 is a diagram showing the frequency characteristics of VSWR at the input port of the coupler according to the fourth embodiment. FIG. 26 is a diagram showing VSWR (frequency characteristics of VSWR viewed from the coupling port) of the sub-line of the coupler according to the fourth embodiment. FIG. 27 is a block diagram illustrating a configuration example of a multiband mobile phone including the coupler according to the present invention. FIG. 28A is a plan view showing the first layer (conductor layer) of the multilayer substrate constituting the coupler according to the comparative example. FIG. 28B is a plan view showing a first insulating layer of the multilayer substrate constituting the coupler according to the comparative example. FIG. 28C is a plan view showing a second layer (conductor layer) of the multilayer substrate constituting the coupler according to the comparative example. FIG. 28D is a plan view showing a second insulating layer of the multilayer substrate constituting the coupler according to the comparative example. FIG. 28E is a plan view showing a third layer (conductor layer) of the multilayer substrate constituting the coupler according to the comparative example (the back side of the substrate is shown in a transparent state). FIG. 29 is a diagram showing frequency characteristics of the coupling degree of the coupler according to the comparative example. FIG. 30 is a diagram showing isolation frequency characteristics of the coupler according to the comparative example. FIG. 31 is a diagram showing the frequency characteristics of the directionality of the coupler according to the comparative example. FIG. 32 is a diagram showing frequency characteristics of insertion loss of the coupler according to the comparative example. FIG. 33 is a diagram showing the frequency characteristics of VSWR at the input port of the coupler according to the comparative example. FIG. 34 is a block diagram illustrating a configuration example of a conventional multiband mobile phone.

[First Embodiment]
As shown in FIG. 1, the coupler 11 according to the first embodiment of the present invention includes a main line 12 that transmits high-frequency power and a sub-line 13 that extracts a part of the high-frequency power transmitted through the main line 12. The main line 12 and the sub line 13 are arranged close to each other, and both lines 12 and 13 are electromagnetically coupled. The main line 12 has an input port P1 at one end and an output port P2 at the other end, and the sub line 13 has a coupling port P3 at one end and an isolation port P4 at the other end.

  The sub-line 13 includes a first sub-line part 13 a and a second sub-line part 13 b that are arranged in different conductor layers and are electrically connected to each other through a via hole (hereinafter referred to as “via”) V 1. Coupling that performs electromagnetic field coupling with the main line 12 (main line coupling portion 22) at one end and the other end, that is, one end of the first sub-line portion 13a and one end of the second sub-line portion 13b. The parts 23a and 24a are formed, respectively. The length of the sub line 13 is longer than that of the main line 12 and has a length that causes resonance at a predetermined frequency (set frequency). Details are as follows.

  The coupler 11 of the present embodiment has a use frequency band of 700 MHz (lower end frequency) to 2.7 GHz (upper end frequency), and a position close to the high frequency side (frequency region higher than the upper end frequency) of this use frequency band (this embodiment). In this case, a resonance point is generated in the vicinity of 3.2 GHz to flatten the coupling within the used frequency band.

  3 to 8 show the frequency characteristics of the coupler of this embodiment. FIG. 3 shows the degree of coupling, and FIG. 8 shows the VSWR (voltage standing wave ratio) of the sub line 13 viewed from the coupling port P3 side. Each is shown. As shown in these figures, in order to generate an attenuation pole due to resonance of the subline 13 at the set frequency 3.2 GHz on the high frequency side of the use frequency band 700 MHz to 2.7 GHz, the length of the subline 13 is set to It has a length that causes resonance at a frequency of 3.2 GHz (for example, a wavelength corresponding to the frequency of 3.2 GHz is λ, and n is a positive integer, a length of (λ / 4) × n).

  The main line 12 may be shorter than the length of the sub-line 13 and may have a length capable of electromagnetic field coupling with the sub-line 13 (the coupling portion 22 can be formed). In addition, the use frequency band is an example, and may be various in addition to these in the present invention. The position (set frequency) at which the resonance point is formed is also the value of the use frequency band (lower end). Various values other than the above may be taken depending on the frequency value and the upper frequency), the bandwidth of the used frequency band, the required specifications, and the like.

  On the other hand, even if the sub-line 13 is longer than that of a conventional general coupler as described above, according to the present invention, the pattern shape of the main line 12 and the sub-line 13 and the arrangement on the multilayer substrate are devised as follows. By doing so, it is possible to realize a small and low-profile coupler without causing an increase in the size of the coupler (an increase in planar shape or an increase in the number of stacked layers).

  2A to 2K show each layer of the multilayer substrate constituting the coupler according to the present embodiment. The coupler according to the present embodiment has a rectangular planar shape including a plurality of conductor layers (hereinafter referred to as a multilayer substrate). The main line, the sub line, each port, and each ground described above are arranged in the internal wiring layer (conductor layer) of the substrate (sometimes simply referred to as “substrate”). 2A to 2K show the layers of the substrate in order from the upper layer (substrate front side) to the lower layer (substrate rear side). Of these drawings, FIGS. 2A, 2C, 2E, 2G, 2I and 2K show conductor layers (first to sixth layers) in which conductor patterns are arranged, and FIG. An insulating layer (referred to as a “first insulating layer”) between the first layer and the second layer is shown. Similarly, FIG. 2D shows an insulating layer (second insulating layer) between the second layer and the third layer, and FIG. 2F shows an insulating layer (third insulating layer) between the third layer and the fourth layer. 2H shows an insulating layer (fourth insulating layer) between the fourth layer and the fifth layer, and FIG. 2J shows an insulating layer (fifth insulating layer) between the fifth layer and the sixth layer. It is shown. The same applies to later-described embodiments (FIGS. 9A to 9I) and comparative examples (FIGS. 21A to 21E).

  In the coupler of the present embodiment, as shown in FIG. 2E, the main line 12, the input port P1, the output port P2, and the intermediate ground G1 are provided in the third layer of the substrate. The input port P1 is arranged at the upper left corner of the third layer when viewed from the plane, and the output port P2 is arranged at the upper right corner. The main line 12 includes an intermediate portion 22 that extends linearly along one side edge of the substrate (in parallel with the one side edge), and an input port that extends between one end of the intermediate portion 22 and the input port P1. A connection end to P1 and a connection end to the output port P2 extending between the other end of the intermediate portion 22 and the output port P2.

  The intermediate portion 22 of the main line 12 is a coupling portion that performs electromagnetic field coupling with the sub-line 13. Specifically, the intermediate portion 22 is connected to the connection end 23a to the coupling port P3 of the fourth sub-line portion 13a of the fourth layer and the isolation port of the second sub-line portion 13b of the second layer, which will be described later. It arrange | positions so that it may overlap with the connection end part 24a when it sees from a plane, and, thereby, the both ends of the main line 12 and the subline 13 are electromagnetically coupled.

  A ground electrode (intermediate ground) G1 is disposed at the center of the third layer surrounded by the input / output ports P1 and P2 and the main line 12. The intermediate ground G1 is interposed between a non-coupling portion 23b of the first sub-line portion 13a described later and a non-coupling portion 24b of the second sub-line portion 13b.

  As shown in FIG. 2G, the coupling port P3 and the first sub line portion 13a are arranged in the fourth layer. The coupling port P3 is disposed at the lower left corner of the fourth layer, and extends along one side edge of the substrate from one end to the other end of the substrate on which the coupling port P3 is disposed (in parallel with the one side edge). The first sub-line portion 13a is extended in a straight line, and the straight line portion (the connection end portion 23a to the coupling port P3) is viewed from the plane with the intermediate portion 22 of the main line 12 arranged in the third layer. It is set as the coupling | bond part 23a by arrange | positioning so that it may overlap sometimes.

  In the fourth layer, the first sub-line portion 13a that is not coupled to the main line 12 is wound by spirally winding the first sub-line portion 13a toward the center of the substrate following the coupling portion 23a. A coupling portion 23b is formed. A via V1 extending through the third insulating layer and the second insulating layer and extending to the second layer is provided in the center of the substrate, and the first sub line portion 13a (non-connecting portion) opposite to the coupling portion 23a is provided in the via V1. The ends of the coupling part 23b) are connected. The uncoupled portion 23b of the first sub-line portion 13a has a narrower line width than the coupled portion 23a (the same applies to the second sub-line portion 13b described below). This is because it is possible to accommodate the long sub-line 13 with a smaller area. Also, from the viewpoint of the same space efficiency, the first sub-line portion 13a and the second sub-line portion 13b have substantially the same length, and the long sub-line 13 is equally divided into two layers (fourth layer and second layer). Arranged.

  As shown in FIG. 2C, the isolation port P4 and the second sub line portion 13b are arranged in the second layer. The isolation port P4 is disposed at the lower right corner of the second layer. Contrary to the first sub-line portion 13a of the fourth layer, the other end of the substrate on which the isolation port P4 is disposed is connected to one end of the substrate. The second sub-line portion 13b is formed so as to extend linearly along one side edge portion (in parallel with the one side edge) of the directing substrate, and the straight line portion (connection end to the isolation port P4) The portion 24a) is arranged so as to overlap with the intermediate portion 22 of the main line 12 arranged in the third layer when viewed from the plane, thereby forming the coupling portion 24a.

  On the other hand, from the via V1 extending from the fourth layer to the second layer arranged in the center of the second layer, the second so as to gradually spread outward toward the coupling portion 24a of the second subline portion 13b. By winding the sub line portion 13b in a spiral shape, a non-coupled portion 24b of the second sub line portion 13b that is not coupled to the main line 12 is formed. The uncoupled portion 24b of the second sub line portion 13b continues to the coupled portion 24a at one side edge of the substrate.

  The direction in which the second sub line portion 13b is wound (the direction of rotation from the via V1 connected to the first sub line portion 13a toward the coupling portion 24a) is the direction of rotation of the first sub line portion 13a (the coupling portion). 23a to the via V1 connected to the second sub line portion 13b), and the same direction (counterclockwise in this example). The uncoupled portion 23b of the first sub-line portion 13a and the uncoupled portion 24b of the second sub-line portion 13b are substantially overlapped when viewed from the plane, but by aligning the direction of winding the line in this way, 2 It is possible to prevent the sub-line portions 13a and 13b arranged in layers from interfering with each other (inhibiting signal transmission with each other). In the present embodiment, in order to prevent such interference between the sub-line portions 13a and 13b (non-coupled portions 23b and 24b), the uncoupled portion 23b of the first sub-line portion 13a and the second sub-line portion 13b An intermediate ground G1 is provided in the third layer so as to be interposed between the non-coupling portion 24b.

  Furthermore, in the coupler according to the present embodiment, as shown in FIG. 2A, a ground electrode (upper ground) G2 extending over substantially the entire surface of the conductor layer is provided in the first layer. The upper ground G2 prevents the coupler 11 according to the present embodiment from being affected by other components and members arranged close to each other at the time of mounting, and the coupling portions 22, 23a, 24a when viewed from above. It is formed so as to cover the non-coupling portions 23b and 24b of the sub-line 13 while avoiding (indicated by symbol A in FIG. 2A). Similarly, as shown in FIG. 2I, the fifth layer is provided with a ground electrode (lower ground) G3 extending over substantially the entire surface of the conductor layer. Similarly to the upper ground G2, the lower ground G3 covers the uncoupled portions 23b and 24b of the sub-line 13 while avoiding the coupled portions 22, 23a and 24a (indicated by reference numeral A in FIG. 2I) when viewed from above. It is formed.

  As shown in FIG. 2K, the sixth layer includes terminals T1, T2, T3, T4, and TG for external connection. That is, the external connection terminals T1 to T4 are arranged so as to correspond to the arrangement positions of the ports P1 to P4 (at positions immediately below the P1 to P4), and via vias V penetrating the substrate substantially vertically. These external connection terminals T1, T2, T3 and T4 are connected to the input port P1, output port P2, coupling port P3 and isolation port P4, respectively.

  Further, the external connection terminals TG provided at both side edges of the center of the sixth layer are terminals for ground electrodes (upper ground G2, intermediate ground G1, lower ground G3). These ground terminals TG and the fifth layer The lower ground G3 is connected via the via V. The intermediate ground G1 of the third layer is formed by the fifth layer by a via V provided in the center of the substrate so as to vertically penetrate the third insulating layer, the fourth layer, and the fourth insulating layer (FIGS. 2F to 2H). The lower ground G3 is connected to the ground terminal TG via the lower ground G3. Further, the upper ground G2 of the first layer is formed by a third layer by a via V provided in the center of the substrate so as to vertically penetrate the first insulating layer, the second layer, and the second insulating layer (FIGS. 2B to 2D). Is connected to the ground terminal TG via the intermediate ground G1 and the lower ground G3.

[Comparative Example]
28A to 28E show a coupler having a conventional structure as a comparison with the present embodiment. As shown in these drawings, in this coupler, a main line 52 is disposed on the first layer of the multilayer substrate, and a sub line 53 is disposed on the second layer, and the intermediate portions 62 and 63 of the main line 52 and the sub line 53 are disposed. Are combined by forming a pattern so as to overlap when viewed from the plane.

  29 to 33 show the frequency characteristics of the coupler according to the comparative example. As is clear from these figures, the minimum value of the coupling degree in the used frequency band of 700 MHz to 2.7 GHz is 25 at 700 MHz. .79 dB and the maximum value is 14.31 dB at 2.7 GHz. Therefore, the variation width Δ of the coupling degree is 11.48 dB, which satisfies the standard of 6 dB or less, which is a generally required variation width. I can't do that at all.

  On the other hand, according to the coupler of the above embodiment, as shown in FIGS. 3 to 8, the minimum value of the coupling degree within the use frequency band (700 MHz to 2.7 GHz) is 25.55 dB at 700 MHz, the maximum value. Is 21.51 dB at 1.8 GHz, and the fluctuation range Δ of the coupling degree is 4.04 dB, which satisfies the standard of 6 dB or less, which is a generally required fluctuation range. In addition, this increases the degree of coupling in the used frequency band (700 MHz to 2.7 GHz) by forming the attenuation pole by resonating the sub-line near 3.2 GHz, and the degree of coupling is suppressed in the used frequency band. This is because it has been flattened.

  As described above, according to the coupler of the present embodiment, the sub-line has a length that causes resonance, and a resonance point (attenuation pole of the degree of coupling) is generated at a position near the high frequency side of the used frequency band. It is possible to flatten the coupling degree by suppressing the fluctuation of the coupling degree in the frequency band.

  In addition to the required specification S1 (FIG. 3) for the coupling degree, these required specifications S2, S3, and S4 related to other directivity (FIG. 5), insertion loss (FIG. 6), and VSWR (FIG. 7) are also shown. Can be fully satisfied.

[Second Embodiment]
As shown in FIGS. 9A to 9I, the coupler according to the second embodiment of the present invention is one in which both ends of the sub-line are coupled to the main line in the same manner as the coupler of the first embodiment. Unlike the first embodiment, the main line 12 is formed to be linearly short.

  Specifically, the main line 12 is arranged along the edge of the substrate so that the input port P1 arranged at the upper left corner of the third layer and the output port P2 arranged at the upper right corner are connected in a straight line. Part 22 was formed. Since the other structure is the same as that of the first embodiment, the same reference numerals are given to the corresponding parts, and redundant description is omitted.

  10 to 15 show the frequency characteristics of the coupler according to this embodiment. As is clear from these figures, this embodiment can also provide better characteristics than the comparative example. . Further, according to the present embodiment in which the main line 12 is shorter than the first embodiment, the insertion loss can be suppressed to a low level.

[Third Embodiment]
In the coupler according to the third embodiment of the present invention, as shown in FIG. 16, the resonance point of the sub-line is positioned within the use frequency band (in the range larger than the lower end frequency and lower than the upper end frequency). Specifically, this coupler has a usable frequency band of 700 MHz to 3.5 GHz, and an attenuation pole due to resonance of the sub line is formed in the vicinity of 2.9 GHz.

  The shape and arrangement of the main line and the sub line are the same as those in the first embodiment (FIGS. 2A to 2K), but the thickness of the first insulating layer is reduced (in the first embodiment, 5 μm). The distance between the first-layer ground electrode (upper ground) G2 and the second-layer second sub-line portion 13b was reduced. By bringing the upper ground G2 closer to the sub line 13 (second sub line part 13b) in this way, radiation from the sub line 13 that also functions as an antenna is suppressed as described above, and the attenuation at the resonance point is reduced. This makes it possible to reduce the fluctuation range of the coupling degree within the use frequency band (to 6 dB or less). Note that the same result can be obtained even if the lower ground G3 is brought closer to the first sub line portion 13a (or both the upper ground G2 and the lower ground G3 are brought closer to the sub line 13).

  FIGS. 17 to 19 show the insertion loss of the coupler according to the present embodiment, the VSWR at the input port, and the VSWR of the sub line as viewed from the coupling port.

  As described above, in the present invention, the attenuation pole due to the resonance of the sub-line 13 may be formed in the use frequency band (in the range larger than the lower end frequency and lower than the upper end frequency).

[Fourth Embodiment]
As shown in FIGS. 20A to 20K, the coupler according to the fourth embodiment of the present invention is obtained by coupling both end portions 23a and 24a of the sub-line 13 to the main line 12 like the coupler of the first embodiment. However, unlike the first embodiment, the coupling portion 22 of the main line 12 and the coupling portions 23a and 24a of the sub-line 13 do not overlap when viewed from a plane.

  Specifically, the coupling portion 23a (FIG. 20G) of the fourth layer sub-line is located obliquely below the coupling portion 22 (FIG. 20E) of the main line, and the coupling portion 24a (FIG. 20A) of the second layer sub-line. 20G) is located obliquely above the coupling portion 22 (FIG. 20E) of the main line, so that the coupling portion 22 of the main line and the coupling portions 23a and 24a of the sub lines are viewed from the plane when viewed from the plane. Although they do not sometimes overlap, they are arranged at positions close to each other (when viewed from a plane, the edges of both coupling portions are in contact with each other).

  FIGS. 21 to 26 show the frequency characteristics of the coupler according to this embodiment. As is clear from these figures, this embodiment can also provide better characteristics than the comparative example. . As described above, in the present invention, both the lines 12 and 13 can be arranged without arranging the coupling part 22 of the main line and the both end parts 23a and 24a of the sub line so as to be completely overlapped as in the first embodiment. By arranging them close to each other, they can be combined to obtain good characteristics.

  Note that in the fourth embodiment, the two contact portions (the main line connection portion 22 and the sub-line connection portions 23a and 24a) have a positional relationship in which the edges contact each other when viewed from the plane. When the part is viewed from a plane, it does not completely overlap as in the first embodiment, but it can be arranged so that a part in the width direction overlaps. The arrangement may be such that there is a gap between the two coupling portions (away from the fourth embodiment), and these structures are also included in the scope of the present invention.

  According to each of the above embodiments, the degree of coupling can be flattened over a wide band, and therefore the number of couplers disposed in a multiband wireless communication apparatus can be reduced.

  For example, when considering the construction of a dual-band mobile phone that can use two communication frequency bands of 800 MHz band and 2 GHz band, the coupling degree greatly varies between the 800 MHz band and the 2 GHz band. Therefore, it was necessary to provide two couplers adjusted so that the degree of coupling was almost equal in each frequency band (800 MHz band and 2 GHz band) in the transmission circuit of each frequency band (see FIG. 34). According to the present embodiment, since the degree of coupling can be flattened over both frequency bands (800 MHz band and 2 GHz band), it is only necessary to provide one common coupler, and the number of components is reduced and the transmission circuit is simplified. Can be

  Specifically, as shown in FIG. 27, according to the present invention, one coupler 11 may be provided between the antenna 101 and the switch 102, and the transmission circuit 201 is simplified as compared with the conventional case (FIG. 34). I can do it. The PA 202 is one that can be used over both frequency bands, and the monitor signal (a signal corresponding to the level of the transmission signal) obtained by the coupler 11 is input to the APC circuit 203. The APC circuit 203 The gain of the PA 202 is controlled so that the output of the PA 202 becomes constant according to the level of the signal (that is, the level of the transmission signal). The switch 102 has a function of distributing radio waves received through the antenna 101 to the receiving circuits 103 and 104 and sending out a transmission signal input from the transmission circuit 201 to the antenna 101. For example, the switch 102 is configured by combining a diplexer and a high-frequency switch. Just do it.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it is obvious to those skilled in the art that various modifications can be made within the scope of the claims. is there.

11, 311, 411 Coupler 12, 52 Main line 13, 53 Sub line 13a First sub line part 13b Second sub line part 22, 62 Coupling part (intermediate part of main line)
23a coupling part (connection end to coupling port)
23b Non-coupling part 24a Coupling part (connection end to isolation port)
24b Non-coupling part 63 Coupling part (intermediate part of sub line)
DESCRIPTION OF SYMBOLS 101 Antenna 102 Switch 103,104 Reception circuit 201,301,401 Transmission circuit 202,302,402 PA (power amplifier)
203, 303, 403 APC circuit (automatic output control circuit)
G1 Intermediate ground G2 Upper ground G3 Lower ground P1 Input port P2 Output port P3 Coupling port P4 Isolation port S1, S2, S3, S4, S5 Required specifications T1, T2, T3, T4, TG External connection terminal V, V1 Via hole

Claims (13)

A main line capable of transmitting high-frequency signals;
An input port for inputting the high-frequency signal to the main line;
An output port for outputting the high-frequency signal from the main line;
A sub-line for extracting a part of the high-frequency signal by electromagnetic coupling with the main line;
A coupling port provided at one end of the sub-line;
An isolation port provided at the other end of the sub-line,
A directional coupler provided in a laminated substrate having a plurality of conductor layers laminated via an insulating layer,
The sub line is longer than the main line,
The main line is disposed on the first conductor layer of the multilayer substrate,
In the second conductor layer below the first conductor layer, a first sub line portion that is a part of the sub line is disposed,
One end of the first subline portion is connected to one of the coupling port and the isolation port,
A second sub line portion that is another part of the sub line is disposed on the third conductor layer above the first conductor layer,
One end of the second subline portion is connected to the other of the coupling port and the isolation port,
The other end portion of the first sub-line portion and the other end portion of the second sub-line portion are electrically connected by an interlayer connection conductor,
When the line part that performs electromagnetic field coupling between the main line and the sub line is referred to as a coupling part, and the line part that does not perform the electromagnetic field coupling is referred to as a non-coupling part,
At least a part of the main line and a part of the first sub-line part are arranged so as to be close to each other, and at least a part of the main line and a part of the second sub-line part are close to each other While disposing the main line, one end portion of the first sub-line portion and one end portion of the second sub-line portion, respectively, a coupling portion is formed,
An intermediate portion of the sub-line extending between the coupling portion of the first sub-line portion and the coupling portion of the second sub-line portion is a non-coupling portion,
When the wavelength corresponding to the set frequency higher than the lower end frequency of the used frequency band is λ and n is a positive integer,
The sub-line has a length of approximately {(λ / 4) × n},
The Thereby, the upper frequency of use higher than the lower end frequency of the frequency band the frequency band used hereinafter, or form a resonance point at a position of the set frequency of the high frequency side than the upper frequency of the frequency band used A directional coupler characterized by flattening the degree of coupling in the operating frequency band. By disposing at least a part of the main line, a part of the first sub-line part, and a part of the second sub-line part when viewed from a plane, the main line, The directional coupler according to claim 1, wherein the coupling portion is formed at one end portion of the first sub-line portion and one end portion of the second sub-line portion, respectively. The directional coupler according to claim 1 or 2, wherein a length of the first sub line portion and a length of the second sub line portion are substantially equal. An intermediate ground which is a ground electrode disposed so as to be interposed between a non-coupling portion of the first sub-line portion and a non-coupling portion of the second sub-line portion in the stacking direction of the multilayer substrate. The directional coupler according to any one of 1 to 3. The directional coupler according to claim 4, wherein the intermediate ground is provided in the first conductor layer. The directional coupler according to any one of claims 1 to 5, further comprising an upper ground that is a ground electrode disposed above the third conductor layer so as to cover a non-coupled portion of the second sub-line portion. . The said upper ground is formed so that it may not overlap with the coupling | bond part of the said main line, the coupling | bond part of a 1st subline part, and the coupling | bond part of a 2nd subline part, when it sees from a plane. Directional coupler. The directional coupler according to claim 1, further comprising a lower ground that is a ground electrode disposed below the second conductor layer so as to cover a non-coupled portion of the first sub-line portion. . The said lower ground is formed so that it may not overlap with the coupling | bond part of the said main line, the coupling | bond part of a 1st subline part, and the coupling | bond part of a 2nd subline part, when it sees from a plane. Directional coupler. The directional coupling according to any one of claims 1 to 9, wherein the uncoupled portion of the first subline portion and the uncoupled portion of the second subline portion are each formed in a spiral shape so as to draw a spiral. vessel. When viewed from the plane,
While arranging the coupling part of the main line, the coupling part of the first sub-line part and the coupling part of the second sub-line part along one side edge of the multilayer substrate,
The interlayer connection conductor is disposed in the center of the multilayer substrate,
A non-coupling portion of the first sub line portion is formed in a spiral shape so as to draw a spiral from one side edge portion of the multilayer substrate toward the center portion of the multilayer substrate,
The uncoupled portion of the second sub-line portion is drawn in a spiral in the same rotational direction as the spiral of the first sub-line portion from the center portion of the multilayer substrate toward one side edge portion of the multilayer substrate. The directional coupler according to any one of claims 1 to 10, wherein the directional coupler is formed in a spiral shape. The directional coupler according to any one of claims 1 to 11, wherein the first sub-line portion and the second sub-line portion have a line width of the non-coupling portion smaller than that of the coupling portion. A transmission circuit capable of generating transmission signals of two or more frequency bands, and including a power amplifier for amplifying the transmission signals and an automatic output control circuit for controlling the output of the power amplifier;
A receiving circuit capable of processing received signals in the two or more frequency bands;
An antenna for transmitting and receiving the transmission signal and the reception signal;
Transmission between the antenna and the transmission circuit and the reception circuit, and transmission of a reception signal received through the antenna to the reception circuit and transmission of a transmission signal output from the transmission circuit to the antenna Switch to do,
A directional coupler that detects a level of a transmission signal output from the power amplifier and outputs the detection signal to the automatic output control circuit;
A wireless communication device that controls an output of the power amplifier based on the detection signal input from the directional coupler,
The wireless communication apparatus according to claim 1, wherein the directional coupler is connected between the antenna and the switch and is the directional coupler according to claim 1.

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