JP2009290422A - Non-reciprocal circuit element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a non-reciprocal circuit element which suppresses an occurrence of waste and burr as much as possible in teardown when an electrical conducting material is arranged in a through-hole formed on a ferrite, and which has fewer possibilities of inducing short. <P>SOLUTION: A non-reciprocal circuit element includes a ferrite 32 to which a direct current magnetic field is applied by a permanent magnet, and a first center electrode 35 and a second center electrode 36 arranged on the ferrite 32. An electrical conducting material is arranged in a through-hole formed on an upper and a bottom portions of the ferrite 32 so as to pass through main surfaces 32a and 32b, and there are electrodes functioning as relaying electrodes 35a, 36b, 36d, 36f, 36h, 36j, 36l, and 36n of the first and the second center electrodes 35 and 36, and electrodes functioning as electrodes 35b, 35c, and 36p connecting to a terminal electrode on a circuit substrate. The relaying electrodes 36d, 36h, and 36l of the bottom portion are not exposed to a bottom surface 32d of the ferrite 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a nonreciprocal circuit device, and more particularly to a nonreciprocal circuit device such as an isolator or a circulator used in a microwave band.

  Conventionally, nonreciprocal circuit elements such as isolators and circulators have a characteristic of transmitting a signal only in a predetermined specific direction and not transmitting in a reverse direction. Utilizing this characteristic, for example, an isolator is used in a transmission circuit unit of a mobile communication device such as a car phone or a mobile phone.

  As a non-reciprocal circuit element of this type, in the 2-port type isolator described in Patent Document 1, the first center electrode and the second center electrode are electrically insulated from each other on two main surfaces of the ferrite that are positioned in parallel to each other. They are crossed. And the 1st and 2nd center electrode arrange | positioned at both main surfaces is electrically connected through the electrically conductive material with which the recessed part (through hole) provided in the upper and lower surfaces of the ferrite was filled, and on the lower surface of a ferrite A conductive material filled in a recess (through hole) provided so as to be exposed is connected to a terminal electrode provided on the surface of the circuit board.

By the way, in the nonreciprocal circuit element described in Patent Document 1, a through hole is formed in a mother ferrite substrate and filled with a conductive material to form an electrode for relay and connection, and then the through hole is overlapped with the mother magnet substrate. A hole (conductive material) is cut to be separated into elements including one ferrite. However, when cutting the conductive material, cutting scraps and burrs are generated, and there is a possibility that these contact with the adjacent conductive material and the terminal electrode on the circuit board to cause a short circuit.
International Publication No. 2007/046229 Pamphlet

  Accordingly, an object of the present invention is to provide a non-reciprocal circuit device that suppresses generation of debris and burrs as much as possible even when a conductive material is disposed in a through hole formed in ferrite, and has a low possibility of causing a short circuit. There is.

In order to achieve the above object, a non-reciprocal circuit device according to one aspect of the present invention comprises:
With permanent magnets,
A ferrite to which a DC magnetic field is applied by the permanent magnet;
A first center electrode and a second center electrode made of a conductor film disposed on two main surfaces of the ferrite that are located in parallel with each other and intersecting each other in an electrically insulated state;
A circuit board having terminal electrodes formed on the surface;
With
One end of the first center electrode is electrically connected to the input port, the other end is electrically connected to the output port, one end of the second center electrode is electrically connected to the output port, and the other end is connected to the ground port. Electrically connected,
The upper and lower portions of the ferrite have a through hole penetrating the main surface, and a conductive material is disposed in the through hole,
The conductive material arranged in the through-hole functions as a relay electrode that connects the first center electrode and the second center electrode provided on the main surface of the ferrite, and a terminal electrode formed on the circuit board. There are those that function as connecting electrodes to be connected,
The conductive material functioning as at least a relay electrode provided in the lower part of the ferrite is not exposed on the lower surface of the ferrite,
It is characterized by.

  When manufacturing a large number of non-reciprocal circuit elements, the mother ferrite substrate is cut into a predetermined unit size. In the non-reciprocal circuit element, since at least the conductive material functioning as a relay electrode provided under the ferrite is not exposed on the lower surface of the ferrite, the conductive material is not cut, and the cutting waste or There is no burrs.

  According to the present invention, since at least a conductive material functioning as a relay electrode provided in the lower portion of the ferrite does not generate cutting scraps or burrs, an inconvenient short circuit on the circuit board can be prevented.

  Embodiments of a nonreciprocal circuit device according to the present invention will be described below with reference to the accompanying drawings.

(Refer 1st Example and FIGS. 1-5)
FIG. 1 shows an exploded perspective view of a 2-port isolator which is a first embodiment of a nonreciprocal circuit device according to the present invention. This two-port isolator is a lumped constant isolator, and generally includes a circuit board 20 and a ferrite magnet element 30 including a ferrite 32 and a pair of permanent magnets 41.

  As shown in FIG. 2, the ferrite 32 is provided with a first center electrode 35 and a second center electrode 36 which are electrically insulated from each other by insulating materials 34A and 34B on the front and back main surfaces 32a and 32b. Yes. Here, the ferrite 32 has a rectangular parallelepiped shape having a first main surface 32a and a second main surface 32b parallel to each other.

  Further, the permanent magnet 41 opposes the main surfaces 32a and 32b so as to apply a magnetic field to the ferrite 32 in a direction perpendicular to the main surfaces 32a and 32b, for example, an epoxy-based adhesive 42 (see FIG. 1). To form a ferrite / magnet element 30. The main surface of the permanent magnet 41 has the same dimensions as the main surfaces 32a and 32b of the ferrite 32, and is disposed with the main surfaces facing each other so that their external shapes match.

  The first center electrode 35 is formed of a conductor film. That is, as shown in FIG. 2, the first center electrode 35 is formed on the first main surface 32a of the ferrite 32 so as to rise from the lower right and incline at the upper left at a relatively small angle with respect to the long side. It rises in the direction and enters the second main surface 32b via the relay electrode 35a on the upper surface 32c. On the second main surface 32b, the first center electrode 35 is formed so as to substantially overlap the first main surface 32a in a see-through state, and one end thereof is connected to the connection electrode 35b formed on the lower surface 32d. The other end of the first center electrode 35 is connected to a connection electrode 35c formed on the lower surface 32d. Thus, the first center electrode 35 is wound around the ferrite 32 for one turn. The first center electrode 35 and the second center electrode 36 intersect with each other in a state where insulating materials 34A and 34B are formed therebetween and insulated from each other. The crossing angle of the center electrodes 35 and 36 is set as necessary, and input impedance and insertion loss are adjusted.

  The second center electrode 36 is formed of a conductor film. In the second center electrode 36, first, the 0.5th turn 36a is inclined at a relatively large angle with respect to the long side from the lower right to the upper left on the first main surface 32a and intersects the first center electrode 35. The first turn 36c is formed in a state of intersecting the first central electrode 35 substantially perpendicularly on the second main surface 32b via the relay electrode 36b on the upper surface 32c. ing. The lower end of the first turn 36c goes around the first main surface 32a via the relay electrode 36d on the lower surface 32d, and the 1.5th turn 36e is parallel to the 0.5th turn 36a on the first main surface 32a. The first central electrode 35 is formed so as to intersect with the second main surface 32b via the relay electrode 36f on the upper surface 32c. Similarly, the second turn 36g, the relay electrode 36h, the 2.5th turn 36i, the relay electrode 36j, the third turn 36k, the relay electrode 36l, the 3.5th turn 36m, the relay electrode 36n, the fourth turn The eyes 36o are formed on the surface of the ferrite 32, respectively. Further, both ends of the second center electrode 36 are connected to connection electrodes 35c and 36p formed on the lower surface 32d, respectively. The connection electrode 35 c is shared as a connection electrode at each end of the first center electrode 35 and the second center electrode 36.

  Further, as shown in FIG. 3, the connection electrodes 35b, 35c, 36p and the relay electrodes 35a, 36b, 36d, 36f, 36h, 36j, 36l, 36n are through holes 37a formed in the upper and lower surfaces 32c, 32d. , 37b, 37c are formed by applying or filling an electrode conductor. In addition, through holes 38a and 38b are formed on the upper and lower surfaces 32c and 32d in parallel with various electrodes, and dummy electrodes 39a, 39b and 39c are formed. This type of electrode is formed by forming a through hole in the mother ferrite substrate in advance, filling the through hole with an electrode conductor, and then cutting at a position where the through hole is divided. Various electrodes may be formed as conductor films in the through holes. In the case of manufacturing by a multi-cavity technique, cutting may be performed in a state where a permanent magnet is also laminated on the mother ferrite substrate via an adhesive.

  By the way, in the first embodiment, the through holes 37a and 38a provided on the upper surface 32c of the ferrite 32 are located on the cut lines of the multiple pieces, and the conductive material disposed in these through holes is exposed on the upper surface 32c. Yes. Through holes 38b and 37b provided on the lower surface 32d of the ferrite 32 are also located on the cut line, and the conductive material disposed in these through holes is exposed on the lower surface 32d. On the other hand, the through holes 37c provided in the lower portion of the ferrite 32 are located inside the cut lines, and the conductive material disposed in these through holes is not exposed to the lower surface 32d.

  The lower surface 32d of the ferrite 32 is a mounting surface to the circuit board 20, and the connection electrodes 35b, 35c, and 36p are soldered to the terminal electrodes 25a, 25b, and 25c on the circuit board 20 as described below. . On the other hand, the conductive materials that are not exposed on the lower surface 32d are relay electrodes 36d, 36h, and 36l, and need not be electrically connected to the terminal electrodes of the circuit board 20. That is, the relay electrodes 36d, 36h, and 36l are not necessarily exposed to the lower surface 32d. Since the relay electrodes 36d, 36h, and 36l filled in the through hole 37c are not cut, there is no generation of cutting scraps and burrs, and an inadvertent short circuit with a nearby conductive material is prevented. The

  As the permanent magnet 41, a strontium-based, barium-based, or lanthanum-cobalt-based ferrite magnet is usually used. As the adhesive 42 for adhering the permanent magnet 41 and the ferrite 32, it is optimal to use a one-component thermosetting epoxy adhesive.

  The circuit board 20 is a laminated board obtained by forming predetermined electrodes on a plurality of dielectric sheets, laminating them, and sintering them. As shown in FIGS. , Matching capacitors C1, C2, Cs1, Cs2, Cp1, Cp2 and a terminating resistor R are incorporated. Terminal electrodes 25a, 25b, and 25c are formed on the upper surface, and external connection terminal electrodes 26, 27, and 28 are formed on the lower surface, respectively.

  The connection relationship between these matching circuit elements and the first and second center electrodes 35 and 36 is, for example, as shown in FIG. 4 as a first circuit example and FIG. 5 as a second circuit example. Here, the connection relationship will be described based on the first circuit example shown in FIG.

  The external connection terminal electrode 26 formed on the lower surface of the circuit board 20 functions as the input port P1, and this terminal electrode 26 is connected to the matching capacitor C1 and the termination resistor R. The electrode 26 is connected to one end of the first center electrode 35 via a terminal electrode 25 a formed on the upper surface of the circuit board 20 and a connection electrode 35 b formed on the lower surface 32 d of the ferrite 32.

  The other end of the first center electrode 35 and one end of the second center electrode 36 are connected to a termination resistor R via a connection electrode 35 c formed on the lower surface 32 d of the ferrite 32 and a terminal electrode 25 b formed on the upper surface of the circuit board 20. And connected to capacitors C 1 and C 2 and to an external connection terminal electrode 27 formed on the lower surface of the circuit board 20. This electrode 27 functions as the output port P2.

  The other end of the second center electrode 36 is formed on the lower surface of the capacitor C2 and the circuit board 20 via the connection electrode 36p formed on the lower surface 32d of the ferrite 32 and the terminal electrode 25c formed on the upper surface of the circuit board 20. The external connection terminal electrode 28 is connected. This electrode 28 functions as a ground port P3.

  In the second circuit example shown in FIG. 5, capacitors Cs1 and Cp1 are connected to the input port P1 side, and capacitors Cs2 and Cp2 are connected to the output port P2 side. These capacitors are used for impedance adjustment. ing.

  The ferrite magnet element 30 is placed on the circuit board 20, and the connection electrodes 35b, 35c, 36p on the lower surface 32d of the ferrite 32 are connected to the terminal electrodes 25a, 25b, 25c on the circuit board 20 by reflow soldering or the like. Integrated.

  In the two-port isolator having the above configuration, one end of the first center electrode 35 is connected to the input port P1, the other end is connected to the output port P2, and one end of the second center electrode 36 is connected to the output port P2. Since the other end is connected to the ground port P3, a two-port lumped constant isolator with low insertion loss can be obtained. Further, during operation, a large high-frequency current flows through the second center electrode 36 and almost no high-frequency current flows through the first center electrode 35.

  Further, since the ferrite 32 and the pair of permanent magnets 41 are integrated with the adhesive 42, the ferrite / magnet element 30 is mechanically stable and becomes a robust isolator that is not deformed or damaged by vibration or impact.

(Refer to the second embodiment, FIG. 6)
FIG. 6 shows the main part (ferrite 32) of the second embodiment of the nonreciprocal circuit device according to the present invention. In the ferrite 32, through holes 37 a and 38 a provided in the upper portion thereof are located on the inner side of the multiple cut lines. Since the conductive material disposed in these through holes is not cut and is not exposed to the upper surface 32c, a short circuit with a nearby conductive material or the like is prevented in advance. The remaining structure of the second embodiment is the same as that of the first embodiment.

(Refer to the third embodiment, FIG. 7)
The principal part (ferrite 32) of the third embodiment of the nonreciprocal circuit device according to the present invention is shown in FIG. The ferrite 32 is provided with through holes 38b and 37b provided at the end of the lower surface 32d inside the end surfaces 32e and 32f of the ferrite 32. Therefore, the conductive material arranged in these through holes is not exposed to the end faces 32e and 32f, and is not cut by the end faces 32e and 32f. Prevented in advance.

(Other examples)
The non-reciprocal circuit device according to the present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the gist thereof.

  For example, if the N pole and S pole of the permanent magnet 41 are reversed, the input port P1 and the output port P2 are switched. In the above embodiment, the matching circuit elements are all built in the circuit board. However, a chip type inductor or capacitor may be externally attached to the circuit board.

  Further, the shapes of the first and second center electrodes 35 and 36 can be variously changed. For example, the first center electrode 35 may be branched into two on the main surfaces 32a and 32b. Moreover, the 2nd center electrode 36 should just be wound 1 turn or more.

1 is an exploded perspective view showing a first embodiment of a non-reciprocal circuit device (2-port isolator) according to the present invention. It is a disassembled perspective view which shows the ferrite with a center electrode. It is a perspective view which shows a ferrite. It is an equivalent circuit diagram showing a first circuit example of a 2-port isolator. It is an equivalent circuit diagram showing a second circuit example of a 2-port isolator. It is a perspective view which shows the ferrite of the nonreciprocal circuit device based on this invention. It is a perspective view which shows the ferrite of the nonreciprocal circuit device based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Circuit board 30 ... Ferrite magnet element 32 ... Ferrite 35 ... 1st center electrode 36 ... 2nd center electrode 35b, 35c, 36p ... Connection electrode (conductive material)
35a, 36b, 36d, 36f, 36h, 36j, 36l, 36n ... Relay electrode (conductive material)
37a, 37b, 37c, 38a, 38b ... through hole 41 ... permanent magnet P1 ... input port P2 ... output port P3 ... ground port

Claims (5)

With permanent magnets,
A ferrite to which a DC magnetic field is applied by the permanent magnet;
A first center electrode and a second center electrode made of a conductor film disposed on two main surfaces of the ferrite that are located in parallel with each other and intersecting each other in an electrically insulated state;
A circuit board having terminal electrodes formed on the surface;
With
One end of the first center electrode is electrically connected to the input port, the other end is electrically connected to the output port, one end of the second center electrode is electrically connected to the output port, and the other end is connected to the ground port. Electrically connected,
The upper and lower portions of the ferrite have a through hole penetrating the main surface, and a conductive material is disposed in the through hole,
The conductive material arranged in the through-hole functions as a relay electrode that connects the first center electrode and the second center electrode provided on the main surface of the ferrite, and a terminal electrode formed on the circuit board. There are things that function as connecting electrodes to be connected,
The conductive material functioning as at least a relay electrode provided in the lower part of the ferrite is not exposed on the lower surface of the ferrite,
A nonreciprocal circuit device characterized by the above.   2. The nonreciprocal circuit device according to claim 1, wherein a conductive material functioning as a relay electrode provided on an upper portion of the ferrite is not exposed on an upper surface of the ferrite. 3.   3. The nonreciprocal circuit device according to claim 1, wherein the conductive material provided at the lower end of the ferrite is not exposed on the end face of the ferrite. 4.   4. The nonreciprocal circuit device according to claim 1, wherein the permanent magnet is fixed to both main surfaces of the ferrite to constitute a ferrite magnet element.   5. The nonreciprocal circuit device according to claim 4, wherein the ferrite-magnet device is configured such that both main surfaces of ferrite are arranged perpendicular to the surface of the circuit board on the circuit board.

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