JP2003110309A - Non-reciprocal circuit device and communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance and small non-reciprocal device and a communication device. SOLUTION: A non-reciprocal circuit device 1 is composed of a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, center electrodes 21 to 23 which are arranged on the ferrite as insulated from it and whose one ends are grounded, matching capacitor elements C1, C2, C13, and C23, a resistor element R, and a metal case. The one ends of the center electrodes 21 to 23 are made to serve as ports P1 to P3, and the other ends of the center electrodes 21 to 23 are electrically connected to a grounding terminal 16. The matching capacitor elements C1 and C2 are electrically connected to the ports P1 and P2 and the grounding terminal 16, respectively. The hot-side terminal electrode and grounding-side terminal electrode of the resistor element R are electrically connected to the port 3 and the grounding terminal 16, respectively. The matching capacitor element C13 is electrically connected to the ports P1 and P3, and the matching capacitor element C23 is electrically connected to the ports P2 and P3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonreciprocal circuit device such as an isolator or a circulator used in a microwave band, and a communication device.

[0002]

2. Description of the Related Art Conventionally, as a lumped-constant type isolator (non-reciprocal circuit element) adopted in a mobile communication device such as a mobile phone, a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, and a ferrite It is known that there are three center electrodes arranged in the center, matching capacitors electrically connected to the respective center electrodes, and a yoke that houses the permanent magnet, the ferrite, the center electrode, and the matching capacitors. .

Generally, those which are mass-produced form an electric equivalent circuit as shown in FIG. In FIG.
C1 to C3 are matching capacitor elements, R is a resistor element, 2
1 to 23 are center electrodes, 14 is an input terminal, 15 is an output terminal, and 16 is a ground terminal. In addition, P1-P
Reference numeral 3 denotes the end portions (port portions) of the center electrodes 21 to 23.

In this isolator 41, matching capacitor elements C1 to C3 are electrically connected in parallel to the respective center electrodes 21 to 23.

[0005]

However, in the isolator 41 having such a circuit configuration, it is necessary to use matching capacitor elements C1 to C3 having a large capacitance value. Therefore, the size of the matching capacitor elements C1 to C3 becomes large, and there is a problem that it is difficult to downsize the isolator 41.

In view of these problems, an isolator 42 as shown in FIG. 7 has been proposed. Isolator 4
2 electrically connects the center electrodes 21 to 23 with matching capacitor elements C12, C13, and C23. That is, the port portions P1 to P3 are electrically connected by the matching capacitor elements C12, C13, and C23.

The isolator 42 having such a circuit configuration has matching capacitor elements C12, C13, C.
23 has a capacitance of about 1/3 of the matching capacitor elements C1 to C3 of the isolator 41 shown in FIG.
It has the advantage of smaller size. Further, as shown in FIG. 8, an isolator 43 in which isolators 41 and 42 are combined is also proposed.

However, these isolators 42, 43
It was found that the insertion loss characteristics were poor and the frequency band in which sufficient isolation was obtained was narrow. Also,
The isolator 43 has a large number of matching capacitor elements,
It is disadvantageous in terms of cost and size.

Here, the relationship between the Q value of the matching capacitor elements C12, C13 and C23 of the isolator 42 shown in FIG. 7 and the insertion loss deterioration amount was measured. Figure 9 shows the measurement results.
Shown in. From FIG. 9, the insertion loss deterioration amount due to the matching capacitor element C12 inserted in series between the input terminal 14 and the output terminal 15 is the same as the matching capacitor elements C13 and C23.
It can be seen that the insertion loss deterioration amount is about 4 times. In other words, if the matching capacitor elements C12, C13, and C23 are formed of materials having the same Q value, the insertion loss deterioration amount due to the matching capacitor element C12 becomes about four times.

Therefore, in order to obtain a good insertion loss characteristic, the matching capacitor element C12, which is inserted in series between the input terminal 14 and the output terminal 15, is compared with other matching capacitor elements C13 and C23. It can be seen that it is desirable to adopt one having a high Q value or to dispose no matching capacitor element between the input terminal 14 and the output terminal 15.

Therefore, an object of the present invention is to provide a high-performance and small-sized nonreciprocal circuit device and a communication device.

[0012]

A non-reciprocal circuit device according to the present invention comprises: (a) a permanent magnet; (b) a ferrite to which a DC magnetic field is applied by the permanent magnet; and (c) the ferrite. First, second, and third parts that are arranged in an insulated state and have one end electrically connected to the ground
Center electrode, (d) a first matching capacitor element electrically connected between the other end of the first center electrode and ground, and (e) the other end of the second center electrode. A second matching capacitor element electrically connected between the
(F) a third matching capacitor element electrically connected between the other end of the first center electrode and the other end of the third center electrode, and (g) the second center electrode. A fourth matching capacitor element electrically connected between the other end of the third center electrode and the other end of the third center electrode; (h) the permanent magnet, the ferrite, the first center electrode, and A metal case that accommodates the second center electrode and the third center electrode is provided. It is preferable to further include a resistance element electrically connected between the other end of the third center electrode and the ground.

With the above structure, the third matching capacitor element and the fourth matching capacitor element are used to match the isolator of the nonreciprocal circuit element, so that the matching capacitor element having a small electrostatic capacitance is used. be able to.

Further, since the matching capacitor element is not electrically connected in series between the other end of the first center electrode and the other end of the second center electrode, the other end of the first center electrode is The insertion loss characteristic of the non-reciprocal circuit element from the portion to the other end of the second center electrode is not deteriorated, and the isolation characteristic can be broadened in band.

The first matching capacitor element and the second matching capacitor element
The matching capacitor element, the third matching capacitor element, and the fourth matching capacitor element are single-plate capacitors, and the first matching capacitor element and the third matching capacitor element overlap each other, and It is preferable that the second matching capacitor element and the fourth matching capacitor element overlap each other. As a result, the area occupied by the matching capacitor element is further reduced, and the nonreciprocal circuit element is downsized.

Further, since the communication device according to the present invention is provided with the nonreciprocal circuit element, the electrical characteristics are improved and the size is reduced.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a nonreciprocal circuit device and a communication device according to the present invention will be described below with reference to the accompanying drawings.

[First Embodiment, FIGS. 1 to 4] FIG. 1 is an exploded perspective view of an embodiment of a nonreciprocal circuit device according to the present invention. The non-reciprocal circuit device 1 is a lumped constant isolator. As shown in FIG. 1, a lumped constant isolator 1
Is roughly the center electrode assembly 13, the resin terminal case 3, the resistance element R, the first matching capacitor element C1, the second matching capacitor element C2, the third matching capacitor element C13, and the fourth matching capacitor element C2. A matching capacitor element C23, a rectangular permanent magnet 9, a metal upper case 4 and a metal lower case 8 are provided. The center electrode assembly 13 is generally first
Of the central electrode 21, the second central electrode 22, the third central electrode 23, and the ferrite 20.

In the center electrode assembly 13, three center electrodes 21 to 23 are arranged on the upper surface of a rectangular microwave ferrite 20 with an insulating sheet (not shown) interposed so as to intersect each other at approximately 120 degrees. ing. These center electrodes 21 to 2
3 makes the common ground electrode 25 of the center electrodes 21 to 23 on one end side abut on the lower surface of the ferrite 20, and the port portion on the other end side (the other end portion of the center electrodes 21 to 23) P
1 to P3 are derived horizontally. The common ground electrode 25 is
It substantially covers the lower surface of the ferrite 20. Center electrode 21-
23 and the ground electrode 25 are made of a conductive material and are integrally formed by punching out and bending a thin metal plate.

The lower metal case 8 has left and right side walls 8b and a bottom portion 8a. In addition, the metal upper case 4
Has a rectangular shape in plan view and has an upper portion 4a and four side walls 4b. The metal upper case 4 and the metal lower case 8 are formed by, for example, punching a plate material having a high magnetic permeability such as iron or silicon steel, bending it, and then plating it.

The resin terminal case 3 has a bottom portion 3a and four side portions 3b. A rectangular window portion 3c is formed at the center of the bottom portion 3a, and a window portion 3d for accommodating the matching capacitor elements C1 and C2 and the resistance element R is formed at the periphery of the window portion 3c. ing.

The resin-made terminal case 3 has an input terminal 14,
The output terminal 15 and the ground terminal 16 are insert-molded. One end of each of the input terminal 14 and the output terminal 15 is exposed on the outer side surface of the resin-made terminal case 3, and the other end is exposed on the inner side surface of the resin-made terminal case 3 so that the input lead electrode 1
4a and an output extraction electrode 15a. Ground terminal 16
Has one end exposed to the outside surface of the resin terminal case 3 and the other end exposed to the inside of the window 3d of the resin terminal case 3 to serve as the ground lead electrode 16a.

In the resistance element R, a hot side terminal electrode and a ground side terminal electrode are formed on both ends of an insulating substrate by thick film printing or the like, and a resistor is arranged between them.

Matching capacitor elements C1, C2, C1
C3 and C23 are single plate capacitors in which capacitor electrodes are provided on the entire upper and lower surfaces.

The above-mentioned components are assembled as follows. First, the resin terminal case 3 is placed on the metal lower case 8. At this time, the bottom 8a of the metal lower case 8 is exposed in the window 3c, and the metal lower case 8 and the ground terminal 16 are electrically connected.

Next, the matching capacitor elements C1 and C2 and the resistance element R are housed in the window portion 3d of the resin terminal case 3. At this time, the capacitor electrodes on the lower surfaces of the matching capacitor elements C1 and C2 are electrically connected to the ground lead electrodes 16a of the ground terminal 16 exposed on the inner side surface of the resin terminal case 3. The ground side terminal electrode of the resistance element R is electrically connected to the ground lead electrode 16a of the ground terminal 16.

Next, matching capacitor elements C13 and C2
3 is placed on the upper surfaces of the matching capacitor elements C1 and C2. At this time, the capacitor electrodes on the lower surface of the matching capacitor elements C13 and C23 are matched to the matching capacitor elements C1 and C.
2 are electrically connected to the capacitor electrodes on the upper surface. In the first embodiment, the matching capacitor element C1
3 and C23 are arranged to overlap the matching capacitor elements C1 and C2 by about half.

Next, the center electrode assembly 13 is placed on the metal lower case 8. At this time, the ground electrode 25 formed on the lower surface of the ferrite 20 is electrically connected to the bottom portion 8a of the metal lower case 8 through the window portion 3c of the resin terminal case 3. The port P1 is electrically connected to the input extraction electrode 14a and the capacitor electrode on the upper surface of the matching capacitor element C1. The port portion P2 is electrically connected to the output extraction electrode 15a and the capacitor electrode on the upper surface of the matching capacitor element C2. The port portion P3 is electrically connected to the capacitor electrodes on the upper surfaces of the matching capacitor elements C13 and C23 and the hot-side terminal electrode of the resistor element R.

Then, the metal upper case 4 is mounted from above. At this time, the permanent magnet 9 is arranged below the upper portion 4a of the metallic upper case 4. The permanent magnet 9
It is arranged above the ferrite 20 of the center electrode assembly 13 and applies a DC magnetic field to the ferrite 20. Side wall 8b of metal lower case 8 and side wall 4b of metal upper case 4
Form a magnetic circuit by being electrically connected to form a magnetic circuit and also function as a yoke.

The matching capacitor elements C1, C2,
The connection of the capacitor electrodes C13 and C23, the terminal electrode of the resistance element R, the ground electrode 25, the ports P1 to P3, and the joining of the metal upper case 4 and the metal lower case 8 are performed by a method such as solder reflow. Be seen.

Thus, the isolator 1 shown in FIG. 2 is obtained. FIG. 3 is an electrical equivalent circuit diagram of the isolator 1 shown in FIG.

In the isolator 1 described above, as the matching capacitor elements C1, C2, C13, C23, matching capacitor elements having a small electrostatic capacity (about half that of the conventional one) can be used. Therefore, the matching capacitor element C1,
Since the sizes of C2, C13, and C23 can be reduced, the overall size of the isolator 1 can be reduced. Furthermore, matching capacitor elements C1 and C
2, C13 and C23 are composed of a single plate capacitor, and a part of the matching capacitor element C1 and the matching capacitor element C1.
3 and the matching capacitor element C23 partially overlaps with the matching capacitor element C23, the area occupied by the matching capacitor elements C1, C2, C13, and C23 in the isolator 1 is further increased. The size of the isolator 1 can be further reduced, and the size of the isolator 1 can be reduced. As a result, the number of matching capacitor elements is increased to four as compared with the conventional isolator 41 shown in FIG. 6, but the isolator 1 smaller than the conventional isolator 41 can be obtained.

Specifically, for example, when the isolator 1 shown in FIG. 3 is used in the frequency band of 900 MHz, the capacitances of the matching capacitor elements C1, C2, C13 and C23 are C1 = 4.4 (pF) and C2, respectively. = 4.4 (pF),
C13 = 4.1 (pF) and C23 = 4.1 (pF), and the capacitance of the matching capacitor element of the entire isolator 1 becomes 17.0 (pF). On the other hand, when the conventional isolator 41 shown in FIG. 6 is used in the frequency band of 900 MHz, the capacitances of the matching capacitor elements C1, C2 and C3 are C1 = 9.2 (pF) and C2 = 9.2 (pF), respectively.
C3 = 17.3 (pF) and the conventional isolator 4
The capacitance of the matching capacitor element as a whole is 35.7 (p
F). That is, it can be seen that the isolator 1 needs only about half the capacitance of the entire matching capacitor element as compared with the conventional isolator 41. That is, when the matching capacitor elements C1, C2, C13, C23 are formed under the same material and thickness conditions, the volume of the matching capacitor elements C1, C2, C13, C23 in the isolator 1 is the same as that of the conventional isolator 41. Capacitor element C
The volume of the isolator 1 can be reduced because the volume is about half the volume of 1 to C3.

Further, the isolator 1 has a port portion P1.
A matching capacitor element is not electrically connected in series between the port and the port P2. In other words, the isolator 1
Omits the matching capacitor element C12 of the isolator 42 shown in FIG. 7 to insulate between the port portion P1 and the port portion P2. Therefore, the port P of the isolator 1
Since the Q value between 1 and the port P2 becomes very large,
The insertion loss deterioration amount of the isolator 1 is reduced (see FIG. 9), and the isolation characteristic can be broadened.

Here, the electrical equivalent circuit diagram of the isolator 1 (see FIG. 3) and the electrical equivalent circuit diagram of the conventional isolator 41 (see FIG. 6) are compared. Matching capacitor elements C13 and C23 in the isolator 1 and the isolator 4
The matching capacitor element C3 in 1 has a port portion P3.
The same effect is obtained in that the matching of is changed. Therefore, a test body (an isolator in which the matching capacitor element C12 is omitted in FIG. 8) is manufactured, and the capacitance values of the matching capacitor elements C1, C2, C3, C13, and C23 are continuously changed to obtain isolator characteristics and matching. Check the total capacitance of the capacitor element for use. Table 1 shows the matching capacitor elements C3, C13, C2 of each test body.
3, the capacitance of C1 and C2 and the resistance value of the resistance element R are shown.

[0036]

[Table 1]

Here, the meaning that the capacitance of the matching capacitor elements C13 and C23 of the test sample No1 is 0 means that the matching capacitor elements C13 and C23 are omitted, and the same electrical equivalent as the isolator 41 shown in FIG. It means a circuit. In addition, the meaning that the capacitance of the matching capacitor element C3 of the test body No6 is 0 means that the matching capacitor element C3
Is omitted, which means that the electrical equivalent circuit is the same as that of the isolator 1 shown in FIG. Further, the capacitance of the matching capacitor element C means the matching capacitor element C.
It means the total value of the capacitances of 3, C13, C23, C1 and C2 (the capacitance of the entire matching capacitor element).

Table 1 shows the isolator characteristics of each of the test pieces No. 1 to No. 6. It can be seen from Table 1 that the smaller the capacitance of the matching capacitor element C3, the wider the 15 dB isolation bandwidth. It is also understood that the smaller the capacitance of the matching capacitor element C3, the smaller the capacitance of all the matching capacitor elements. That is, the size of the isolator can be reduced. Therefore, the test body N
Matching capacitor element C, like an o6 isolator
It can be seen that the isolator 1 can be downsized and a wide isolation band can be realized by omitting 3 and adopting a structure using the matching capacitor elements C13 and C23. That is, since the matching capacitor element is not electrically connected in series between the port portion P1 and the port portion P2, the insertion loss characteristic of the isolator 1 is not deteriorated and the isolation characteristic can be broadened. it can. Therefore, the high-performance isolator 1 can be obtained.

Incidentally, in addition to the terminals 14, 15 and 16 of the isolator 1 shown in FIG. 1, a terminal 17 is newly provided to electrically connect the port portion P3 to the terminal 17, and
By omitting the resistance element R, the circulator 2
(See FIG. 4) is obtained. At this time, the terminal 14 serves as a transmission terminal, the terminal 15 serves as an antenna terminal, and the terminal 1
Reference numeral 7 is a receiving terminal. Since the circulator 2 uses the matching capacitor elements C1, C2, C13 and C23 described above, the same effect of miniaturization as the isolator 1 described above can be obtained.

Further, in this circulator 2, the signal passing direction is defined by the transmitting terminal 14-antenna terminal 15
Between the antenna terminal 15 and the receiving terminal 17, and between the transmitting terminal 14 and the receiving terminal 17. Transmitting terminal 1 having no matching capacitor element among these three directions
The insertion loss characteristics do not deteriorate between the 4-antenna terminals 15,
In addition, the characteristic that the isolation is in a wide band can be obtained.

Therefore, as shown in FIG. 4, by mounting the circulator 2 on the mobile phone (communication device) 100, the call waiting time of the mobile phone 100 can be extended. Here, FIG. 4 is a block diagram of an electric circuit of the RF portion of the mobile phone 100. In FIG. 4, 102 is an antenna element, 112 is a transmitting side amplifier, 113 is a transmitting side low pass filter, 115 is a receiving side amplifier, 116 is a receiving side inter-stage band pass filter, and 117 is a changeover switch.

In general, a mobile phone is required to extend the standby time of the phone (the time during which continuous reception is possible). However, if the loss of the components of the transmission system is large, the power (battery) of the mobile phone is consumed so much that the standby time of the mobile phone becomes short. Therefore, the circulator 2 described above is installed in the mobile phone 1
No. 00, the transmission radio wave (signal) passes in the direction, that is, from the transmission terminal 14 to the antenna terminal 15
It is possible to reduce the insertion loss in the direction of. Therefore, it is possible to provide the mobile phone 100 that is small in size and has a long phone standby time.

[Second Embodiment, FIG. 5] In the present second embodiment, an embodiment of a communication device will be described taking a mobile phone as an example.

FIG. 5 is an electric circuit block diagram of the RF portion of the mobile phone 120. 5, 122 is an antenna element, 123 is a duplexer, 131 is a transmission side isolator, 132 is a transmission side amplifier, 133 is a transmission side interstage bandpass filter, 134 is a transmission side mixer, 135 is a reception side amplifier, 136 is Bandpass filter for receiving side interstage, 1
37 is a receiving side mixer, 138 is a voltage controlled oscillator (VC
O) and 139 are local band pass filters.

Here, the lumped constant isolator 1 of the first embodiment can be used as the transmission side isolator 131. By mounting this isolator 1, a small-sized and high-performance mobile phone can be realized.

[Other Embodiments] The present invention is not limited to the above-described embodiments, but can be modified into various configurations within the scope of the gist of the present invention. For example, the detailed structure of the metal upper case 4, the metal lower case 8, the resin terminal case 3, the ferrite 20, the permanent magnet 9, etc., which are the components of the isolator 1, is arbitrary. In particular, the center electrodes 21 to 2 of the center electrode assembly 13 shown in the first embodiment.
3 may be formed by punching and bending a thin metal plate, and may be formed by winding a center electrode made of a metal wire (for example, copper) around the ferrite 20. As a result, the center electrodes 21 to 23 need to be formed by punching or etching a thin metal plate, but in the case of a metal wire rod, there is no need to form them, so the forming cost of the center electrodes 21 to 23 is suppressed. be able to. The center electrodes 21 to 23 can also be formed by etching a metal thin plate and then bending it, or by forming a pattern electrode on a substrate (dielectric substrate, magnetic substrate, laminated substrate, etc.). You can Further, the shape of the center electrode assembly 13 is not limited to a rectangular shape, but may be a disc shape, a deformed angular shape, or the like.

Further, although the crossing angle of each of the center electrodes 21 to 23 is described as 120 degrees, it is not limited to this and may be in the range of 110 to 140 degrees. Further, the metal case has been described as being composed of the metal upper case 4 and the metal lower case 8, but the metal case is not limited to this and may be divided into three or more. Further, the shape of the permanent magnet 9 may be, for example, a rectangular shape with rounded corners, a circular shape, or a deformed angular shape other than the rectangular shape.

The present invention can be applied to various non-reciprocal circuit devices in addition to the isolator and the circulator.

[0049]

As is apparent from the above description, according to the present invention, the nonreciprocal circuit element is used as a third matching capacitor element and a fourth matching capacitor element for matching with a small capacitance. A capacitor element can be used. Therefore, the non-reciprocal circuit device and the communication device can be downsized.

In the non-reciprocal circuit device, the matching capacitor device is not electrically connected in series between the other end of the first center electrode and the other end of the second center electrode. The insertion loss characteristic of the circuit element does not deteriorate, and the isolation characteristic can have a wide band. Therefore, a high-performance non-reciprocal circuit device and a communication device can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a non-reciprocal circuit device according to the present invention.

2 is an external perspective view of the nonreciprocal circuit device shown in FIG. 1 after completion of assembly.

3 is an electrical equivalent circuit diagram of the nonreciprocal circuit device shown in FIG.

4 is an electric circuit block diagram of a communication device in which a modification of the nonreciprocal circuit device shown in FIG. 2 is mounted.

FIG. 5 is an electric circuit block diagram of a communication device according to the present invention.

FIG. 6 is an electrical equivalent circuit diagram of a conventional non-reciprocal circuit device.

FIG. 7 is an electrical equivalent circuit diagram of another conventional non-reciprocal circuit device.

FIG. 8 is an electrical equivalent circuit diagram of still another conventional non-reciprocal circuit device.

9 is a graph showing the relationship between the insertion loss deterioration amount and the Q value of the nonreciprocal circuit device shown in FIG.

[Explanation of symbols]

1. Lumped constant isolator (non-reciprocal circuit element) 2 ... Circulator (non-reciprocal circuit element) 4 Metal upper case (metal case) 8 ... Metal lower case (metal case) 9 ... Permanent magnet 13 ... Center electrode assembly 20 ... Microwave ferrite 21 ... First center electrode 22 ... Second center electrode 23 ... Third center electrode 100, 120 ... Mobile phone (communication device) C1 ... First matching capacitor element C2 ... Second matching capacitor element C13 ... Third matching capacitor element C23 ... Fourth matching capacitor element P1 ... Port (the other end of the first center electrode) P2 ... Port (the other end of the second center electrode) P3 ... Port (the other end of the third center electrode)

Claims (4)

[Claims] 1. A permanent magnet, a ferrite to which a direct-current magnetic field is applied by the permanent magnet, and first, second, and second ends that are arranged in an insulated state with respect to the ferrite and electrically connect one end of each to ground. A third center electrode, a first matching capacitor element electrically connected between the other end of the first center electrode and the ground, and between the other end of the second center electrode and the ground. A second matching capacitor element electrically connected, and a third matching capacitor electrically connected between the other end of the first center electrode and the other end of the third center electrode. An element, a fourth matching capacitor element electrically connected between the other end of the second center electrode and the other end of the third center electrode, the permanent magnet, the ferrite, and the fourth One center electrode, the second center electrode, and the third center Non-reciprocal circuit element characterized by comprising: a metal case for accommodating the pole, the. 2. The first matching capacitor element, the second matching capacitor element, the third matching capacitor element, and the fourth matching capacitor element are single plate capacitors, and 2. The matching capacitor element of 3 and the third matching capacitor element overlap each other, and the second matching capacitor element and the fourth matching capacitor element overlap each other. The nonreciprocal circuit device described in 1. 3. The nonreciprocal circuit device according to claim 1, further comprising a resistance element electrically connected between the other end of the third center electrode and the ground. . 4. A communication apparatus comprising the nonreciprocal circuit device according to claim 1. Description: