JP4345691B2 - Non-reciprocal circuit device and communication device - Google Patents

Description

  The present invention relates to a nonreciprocal circuit element, and more particularly to a nonreciprocal circuit element such as an isolator or a circulator used in a microwave band, and a communication apparatus including the element.

  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.

  Conventionally, as a non-reciprocal circuit element, Patent Document 1 discloses that a ferrite / magnet assembly is formed by sandwiching a ferrite in which a central electrode is formed by an electrode film between two permanent magnets. A device vertically arranged in the vertical direction is disclosed.

  However, in this nonreciprocal circuit element, the terminal member is extended from the center electrode and connected to the terminal electrode on the circuit board, and it is difficult to stably and reliably mount the ferrite and the permanent magnet on the circuit board. It had the problem of being.

  On the other hand, when a ferrite and a permanent magnet are juxtaposed, a magnetic field generated from the permanent magnet is applied efficiently and uniformly to the ferrite to prevent a reduction in insertion loss as a nonreciprocal circuit element. It is preferable to match the centers of each other.

Patent Document 2 discloses a configuration in which the center of a ferrite in which a copper wire is routed as a center electrode is made to coincide with the center of a permanent magnet on a circuit board. However, this configuration has a problem in that a support base is provided on the circuit board and ferrite is placed on the support base, which increases the number of components and deteriorates the assemblability.
JP 2002-261513 A Japanese Patent Laid-Open No. 2002-198707

  Accordingly, an object of the present invention is to apply a magnetic field of a permanent magnet to a ferrite effectively without impairing assemblability with a simple configuration, and to mount the ferrite on a circuit board stably and reliably. An object of the present invention is to provide a nonreciprocal circuit element and a communication apparatus including the element.

In order to achieve the above object, a non-reciprocal circuit device according to the present invention comprises:
In a nonreciprocal circuit element comprising a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, a plurality of center electrodes arranged on the ferrite, and a circuit board on which a terminal electrode is formed on the surface,
A plurality of the central electrodes are formed on the main surface of the ferrite by a conductor film in a state where they are insulated from each other, and a relay electrode connected to the central electrode is formed by a conductive film on the upper surface orthogonal to the main surface. The connecting electrode connected to the center electrode is formed by a conductor film on the lower surface orthogonal to the main surface, and the connecting electrode is formed thicker than the relay electrode,
Both the ferrite and the permanent magnet have a rectangular parallelepiped shape, the main surface of the ferrite is smaller than the main surface of the permanent magnet, and each main surface on the circuit board is in a direction perpendicular to the surface of the circuit board. It is juxtaposed with the center of the main surface approximately aligned,
The connection electrode formed on the lower surface of the ferrite is electrically connected to the terminal electrode formed on the surface of the circuit board;
It is characterized by.

  In the nonreciprocal circuit device according to the present invention, since the ferrite and the permanent magnet are juxtaposed on the circuit board in a state where the centers of the respective principal surfaces are substantially coincident, the magnetic field is efficiently generated from the permanent magnet to the ferrite. It is applied substantially uniformly, and characteristics such as insertion loss are improved. And since the small size ferrite has a thick connection electrode on the bottom surface orthogonal to the main surface, when placing the large size permanent magnet and the circuit board side by side, a support base is provided, or the circuit board surface is provided. Without forming irregularities, the center positions (height positions) of the principal surfaces of each other can be aligned, and the connection electrodes can be electrically connected to the terminal electrodes on the circuit board by soldering or the like. In other words, the thickness of the connection electrode can absorb the size difference from the permanent magnet to ensure efficient application of the magnetic field, and the ferrite and the permanent magnet can be stably and reliably mounted on the circuit board.

  In the nonreciprocal circuit device according to the present invention, the connection electrode can be formed thick by printing or transferring a conductive film made of paste a plurality of times. The conductor film of the center electrode and the relay electrode can be formed by various methods such as printing, vapor deposition, sputtering, bonding, and plating.

  Furthermore, the ferrite is preferably sandwiched between two permanent magnets. A magnetic field can be applied to ferrite more efficiently and uniformly. In this case, it is preferable that a pair of permanent magnets having substantially the same shape are bonded to the opposing main surfaces of the ferrite and integrated with the ferrite. The production efficiency of the ferrite / magnet assembly is improved, and it can be efficiently mounted on the circuit board.

  In the nonreciprocal circuit device according to the present invention, the center electrode includes a first center electrode having one end electrically connected to the first input / output port and the other end electrically connected to the second input / output port. A second center electrode that intersects the first center electrode in an electrically insulated state and has one end electrically connected to the second input / output port and the other end electrically connected to the grounding third port. It is preferable to be configured. Thus, a small lumped constant isolator can be obtained. The circuit board may include a matching circuit element, which can further reduce the size of the nonreciprocal circuit element.

  In addition, the communication device according to the present invention includes the nonreciprocal circuit element, so that preferable electrical characteristics can be obtained and the device can be reduced in size and height.

  According to the present invention, a magnetic field is efficiently and substantially uniformly applied to the ferrite from the permanent magnet, characteristics such as insertion loss are improved, and the center position (height position) of each other's main surface can be easily obtained. ), And ferrite and permanent magnets can be stably and reliably mounted on the circuit board.

  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.

(See the main part of the present invention, FIGS. 10 to 12)
First, the main part of the non-reciprocal circuit device according to the present invention will be described. As shown in FIG. 10, the non-reciprocal circuit device according to the present invention has a ferrite 32 and a permanent magnet 41 placed vertically on a circuit board 20 (respective main surfaces 32a, 32b, 41a are arranged on the circuit board 20). The connection electrode 32x formed on the lower surface of the ferrite 32 is made thicker than the relay electrode 32y formed on the upper surface, and the center C1 of the ferrite 32 is made to coincide with the center C2 of the permanent magnet 41. It is in the point. The connection electrode 32x is connected to a terminal electrode (not shown) formed on the circuit board 20 by solder 23 or the like, and the lower surface of the permanent magnet 41 is joined to the circuit board 20 by an adhesive or the like. Further, both the ferrite 32 and the permanent magnet 41 have a rectangular parallelepiped shape, and the main surfaces 32 a and 32 b of the ferrite 32 are smaller than the main surface 41 a of the permanent magnet 41.

  FIG. 11 shows, as a comparative example, a case where the relay electrode 32y and the connection electrode 32x are formed as conductor films having the same thickness on the upper and lower surfaces of the ferrite 32, respectively. In this case, the center C1 of the small-sized ferrite 32 is inevitably lower than the center C2 of the permanent magnet 41, and a deviation amount ΔX is generated between the two.

  The insertion loss of the nonreciprocal circuit element is reduced by the shift amount ΔX. FIG. 12 shows the relationship between the deviation ΔX actually measured by the inventor and the insertion loss. As is apparent from this graph, the lowest loss is obtained when the centers C1 and C2 substantially coincide. In order to ensure a practical insertion loss, it is desirable that the shift amount ΔX be within ± 20%.

  In this data measurement, the ferrite 32 has a long side length of 2.0 mm, a short side length of 0.8 mm, and a thickness of 0.3 mm. The permanent magnet 41 has a long side length of 2.1 mm and a short side. The length is 1.0 mm, the thickness is 0.45 mm, and the ferrite 32 is sandwiched between the two magnets 41. In order to apply a magnetic field to the ferrite 32, it is also possible to place a permanent magnet opposite to only one main surface of the ferrite 32. However, arranging the pair of permanent magnets 41 so as to face both the main surfaces 32a and 32b of the ferrite 32 is more advantageous for the efficient and uniform application of the magnetic field.

(Non-reciprocal circuit device, see FIGS. 1 to 6)
Examples of the non-reciprocal circuit device according to the present invention will be described below. FIG. 1 is an exploded perspective view of a two-port isolator 1 according to an embodiment of the present invention. The two-port isolator 1 is a lumped constant isolator, which is generally a permanent metal for applying a DC magnetic field to the metal yoke 10, the circuit board 20, the center electrode assembly 31 including the ferrite 32, and the ferrite 32. It is formed with magnets 41 and 41.

  The yoke 10 is made of a ferromagnetic material such as soft iron, is silver-plated, and has a frame shape surrounding the central electrode assembly 31 and the permanent magnets 41 and 41 on the circuit board 20.

  A cap 15 made of an insulator (for example, resin or ceramic) is bonded to the upper surfaces of the ferrite 32 and the permanent magnets 41 and 41.

  As shown in FIG. 2, the center electrode assembly 31 is formed by forming a first center electrode 35 and a second center electrode 36 that are electrically insulated from each other on the main surfaces 32 a and 32 b of the microwave ferrite 32. 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, and the first main surface 32a and the second main surface 32b are arranged on the circuit board 20 in a substantially vertical direction. ing.

  The permanent magnets 41 and 41 are bonded to the main surfaces 32a and 32b so that a magnetic field is applied to the main surfaces 32a and 32b in a direction substantially perpendicular to the main surfaces 32a and 32b. 30 is formed. The configuration and manufacturing process of the ferrite / magnet assembly 30 will be described in detail below.

  As shown in FIG. 2, the first center electrode 35 is formed on the first main surface 32a of the ferrite 32 from the lower right and is inclined to the upper left at a relatively small angle with respect to the long side, and rises to the upper left. The connection electrode 35b formed on the lower surface 32d is formed so as to go around the second main surface 32b via the relay electrode 35a on the upper surface 32c and overlap the first main surface 32a in a transparent state on the second main surface 32b. It is connected to the.

  In the second center electrode 36, first, the 0.5th turn 36a intersects with the first center electrode 35 at a relatively large angle with respect to the long side from the substantially central portion of the lower side to the upper left on the first main surface 32a. The first turn 36c is inclined to the left on the second main surface 32b at a relatively large angle on the second main surface 32b via the relay electrode 36b on the upper surface 32c. It is formed so as to intersect with the electrode 35. The lower end of the first turn 36c wraps around the first main surface 32a via the connection electrode 36d on the lower surface 32d, and this 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. The second turn 36g is also formed on the second main surface 32b so as to intersect the first center electrode 35 in parallel with the first turn 36c, and is connected to the connection electrode 36h on the lower surface 32d.

That is, the second center electrode 36 is wound around the ferrite 32 in a spiral manner for two turns. Here, the number of turns is calculated by assuming that the state in which the center electrode 36 crosses the first or second main surface 32a, 32b once each is 0.5 turns. The crossing angle of the center electrodes 35 and 36 is set as necessary, and the input impedance and insertion loss are adjusted.

  The circuit board 20 is a laminated substrate obtained by forming predetermined electrodes on a plurality of dielectric sheets, laminating them, and sintering them. As shown in FIG. 3, matching capacitors C1, C2 , Cs1, Cs2, Cp1, Cp2 and a termination resistor R are incorporated. Terminal electrodes 25a to 25g 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 will be described with reference to the equivalent circuits of FIGS. The equivalent circuit of FIG. 4 shows a basic first circuit example in the non-reciprocal circuit device (2-port isolator 1) according to the present invention, and the equivalent circuit of FIG. 5 shows a second circuit example. FIG. 3 shows the configuration of the second circuit example.

  That is, the external connection terminal electrode 26 formed on the lower surface of the circuit board 20 functions as the input port P1, and this electrode 26 is connected to the connection point 21a between the matching capacitor C1 and the termination resistor R via the matching capacitor Cs1. It is connected. The connection point 21 a is connected to one end of the first center electrode 35 through a terminal electrode 25 a formed on the upper surface of the circuit board 20.

  The other end of the first center electrode 35 is connected to a termination resistor R and capacitors C1 and C2 via a connection electrode 35c formed on the lower surface 32d of the ferrite 32 and a terminal electrode 25b formed on the upper surface of the circuit board 20. Yes.

  On the other hand, the external connection terminal electrode 27 formed on the lower surface of the circuit board 20 functions as the output port P2, and this electrode 27 is connected to the connection point 21b of the capacitors C2 and C1 via the matching capacitor Cs2.

  One end connection electrode 36 i (formed on the lower surface 32 d of the ferrite 32) of the second center electrode 36 is connected to the connection point 21 b via a terminal electrode 25 c formed on the upper surface of the circuit board 20. The other end connection electrode 36 h of the second center electrode 36 is connected to an external connection terminal electrode 28 formed on the lower surface of the circuit board 20 via a terminal electrode 25 d formed on the upper surface of the circuit board 20. The external connection terminal electrode 28 functions as a ground port P3. The external connection terminal electrode 28 is also connected to the yoke 10 via terminal electrodes 25e and 25f formed on the upper surface of the circuit board 20.

  A grounded impedance adjusting capacitor Cp1 is connected to a connection point between the input port P1 and the capacitor Cs1. Similarly, a grounded impedance adjusting capacitor Cp2 is also connected to a connection point between the output port P2 and the capacitor Cs2.

  The circuit board 20 and the yoke 10 are soldered and integrated through terminal electrodes 25e and 25f, and the ferrite / magnet assembly 30 is connected to various connection electrodes 35b, 35c, 36d, 36h, and 36i on the lower surface 32d of the ferrite 32. Are soldered and integrated with the terminal electrodes 25a to 25d and 25g on the circuit board 20, and the lower surfaces 41d and 41d of the permanent magnets 41 and 41 are integrated with the adhesive 24 on the circuit board 20 ( (See FIG. 6). The terminal electrode 25g to which the connection electrode 36d is connected is a dummy electrode. FIG. 6 is a cross-sectional view taken along the line AA in FIG.

  In the two-port isolator 1 having the above configuration, the ferrite 32 in which the first and second center electrodes 35 and 36 are formed with the pair of permanent magnets 41 and 41 having the same shape facing each other is sandwiched. The surfaces 32a and 32b are smaller than the main surface 41a of the permanent magnet 41 (see FIG. 6), and as described in FIG. 10, the connection electrodes 32x (35b, 35c, 36d, 36h, 36i) are formed thick. Since the center C1 of the ferrite 32 and the center C2 of the permanent magnet 41 are arranged so as to substantially coincide with each other, the permanent magnet 41 generates a DC magnetic flux having a good parallelism and a uniform magnetic field is applied to the ferrite 32. The electrical characteristics such as the insertion loss of 1 are improved (see FIG. 12).

  The ferrite 32 has main surfaces 32 a and 32 b arranged on the circuit board 20 in a substantially vertical direction, and the permanent magnets 41 and 41 apply a magnetic field to the main surfaces 32 a and 32 b of the ferrite 32 in a substantially vertical direction. In other words, since the ferrite 32 and the permanent magnets 41 and 41 are vertically arranged on the circuit board 20 in order to obtain a large magnetic field, the permanent magnets are arranged on the circuit board 20. Even if the thickness of 41, 41 is increased, the height does not increase regardless of the thickness, and a reduction in size and height is achieved.

  Furthermore, as shown in the second circuit example (see FIG. 5), the connection point 21a between the first center electrode 35 and the capacitor C1 and the input port P1, and the connection point 21b between the center electrodes 35 and 36, Since only one matching capacitor Cs1, Cs2 is inserted between the output port P2 and the inductance of the center electrodes 35, 36 is set large to improve the electrical characteristics in a wide band, the device is connected to the isolator. The impedance (50Ω) can be matched. This effect can be achieved by simply inserting one of the matching capacitors Cs1 and Cs2.

  If a matching inductor is inserted between the connection point of the second center electrode 36 and the capacitor C2 and the ground port P3, a desired high frequency such as a second harmonic or a third harmonic can be suppressed. Further, an LC series circuit composed of an inductor and a capacitor may be inserted between the input port P1 and the ground and between the output port P2 and the ground. By providing such an LC series circuit, a desired high frequency such as a second harmonic or a third harmonic can be suppressed.

  Here, the ferrite / magnet assembly 30 will be described. As shown in FIG. 6, on the main surfaces 32a and 32b of the ferrite 32, a first center electrode 35 made of a conductor film, an insulator film 37, a second center electrode 36 made of a conductor film, and an insulator film 38 are formed. It is a membrane. Further, relay electrodes 35a, 36b, and 36f are formed of a conductor film on the upper surface 32c of the ferrite 32, and connection electrodes 35b, 35c, 36d, 36h, and 36i are formed of a conductor film on the lower surface 32d.

  The center electrodes 35 and 36 are formed on the main surfaces 32a and 32b of the ferrite 32 with an electrode film material made of silver, copper, gold or an alloy thereof, or a conductor composite material made of a conductive powder such as gold or silver and an epoxy resin (paste or adhesive). It is formed as a thin film by printing or transfer using an electrode film material such as an agent. Alternatively, the electrode film material and the photosensitive material may be mixed and formed into a predetermined shape using a processing technique such as photolithography or etching.

  One or more conductor films and insulator films 37 and 38 of the center electrodes 35 and 36 are provided as necessary, and in some cases, different layers are formed via holes (via holes) formed in the insulator films 37 and 38. You may connect conductor films.

  The relay electrodes 35a, 36b, and 36f are electrode films such as an electrode film material made of silver, copper, gold or an alloy thereof, or a conductor composite material (paste or adhesive) made of conductor powder such as gold or silver and epoxy resin. The material is formed as a thick film by printing or transferring. Alternatively, the electrode film material and the photosensitive material may be mixed and formed into a predetermined shape using a processing technique such as photolithography or etching.

  The connection electrodes 35b, 35c, 36d, 36h, and 36i are electrode film materials made of silver, copper, gold or an alloy thereof, or conductor composite materials (paste or adhesive) made of conductor powder such as gold or silver and epoxy resin. The electrode film material such as is formed thicker than the relay electrodes 35a, 36b, and 36f by repeating printing and transfer a plurality of times.

  Further, the relay electrodes 35a, 36b, and 36f may be formed by dry plating that is a thin film forming technique, and the connection electrodes 35b, 35c, 36d, 36h, and 36i may be formed by printing and baking that is a thick film forming technique. .

  Permanent magnets 41 and 41 are bonded to the main surfaces 32 a and 32 b of the ferrite 32 through an adhesive layer 42. A double-sided PSA sheet may be used in place of the adhesive layer 42.

  As shown in FIG. 6, the connection electrodes 35b, 35c, 36d, 36h, 36i formed on the lower surface 32d of the ferrite 32 are joined to the terminal electrodes 25a-25d, 25g formed on the upper surface of the circuit board 20 by the bonding material 23 (for example, , Solder). Further, the lower surface 41 d of the permanent magnet 41 is bonded onto the circuit board 20 with the adhesive 24. As the adhesive 24, a thermosetting one-component or two-component epoxy adhesive is suitable.

  In this isolator 1, since the rectangular parallelepiped ferrite 32 is used, the joint surface with the circuit board 20 becomes planar, and various connection electrodes are formed on the lower surface 32d. Connection with the terminal electrodes 25a to 25d and 25g formed on the substrate 20 is surely and easily performed. Further, the various connection electrodes need only be formed on one surface, and the manufacturing process is simplified.

  The ferrite 32 is soldered with terminal electrodes 25a to 25d and 25g formed on the circuit board 20 with various connection electrodes formed on the lower surface 32d, and the lower surfaces 41d of the permanent magnets 41 and 41 are connected to the circuit board 20 respectively. Is bonded to the surface of the substrate directly or via a terminal electrode with an adhesive 24, that is, by using both soldering and bonding for bonding the ferrite / magnet assembly 30 and the circuit board 20. It will be certain.

If only the soldering is performed, when the isolator 1 is mounted on the substrate of the communication device by reflow soldering, the solder in this portion melts and the position of the ferrite / magnet assembly 30 is shifted, resulting in failure or deterioration of characteristics. Cause. If the thermosetting adhesive 24 is used in combination, such failure and characteristic deterioration can be prevented in advance. Further, even when the permanent magnet 41 and the ferrite 32 are detached, the permanent magnet 41 is adhered on the circuit board 20, so that a predetermined electrical constant is maintained and a highly reliable nonreciprocal circuit element is obtained. be able to.

  In addition to soldering as described above, various connection electrodes formed on the lower surface 32d of the ferrite 32 are joined to the terminal electrodes 25a to 25d and 25g formed on the upper surface of the circuit board 20 by a sintered film electrode material. , Soldering or bumping bumps such as gold by increasing the temperature using ultrasonic waves, or curing a conductive composite material (paste or adhesive) composed of conductive powder such as gold or silver and epoxy resin Or the like can be employed.

  Here, in the ferrite-magnet assembly 30, a dimensional difference α is provided between the lower surface 32d of the ferrite 32 and the lower surface 41d of the permanent magnet 41 (see FIG. 6). Due to the existence of this dimensional difference α, the thicknesses of various connection electrodes, the thickness of the bonding material 23 such as solder bonded to the connection electrodes, and the thicknesses of the terminal electrodes 25a to 25d and 25g formed on the circuit board 20 The thickness of the adhesive 24 of the permanent magnet 41 is substantially flush with the surface of the circuit board 20. As a result, the ferrite / magnet assembly 30 can be mounted on the circuit board 20 in an accurate and reliable state without tilting.

  In addition, since the ferrite 32 on which the center electrodes 35 and 36 are formed is accurately fixed to a predetermined portion of the permanent magnet 41 by adhesion, a stable isolator with almost no magnetic loss can be manufactured. In particular, when an adhesive sheet is used for bonding the permanent magnet 41 and the ferrite 32, the positional relationship between the ferrite 32 and the permanent magnet 41 can be integrated with a preferable parallelism due to the stability of the thickness of the adhesive layer. .

  The distance between the opposing surfaces of the pair of permanent magnets 41 and 41 is also determined by the thickness of the adhesive layer 42 and the thickness of the ferrite 32, and the magnetic circuit can be formed with the desired constant and stably (with little variation). it can. As a result, stable mass production of the isolator is possible and is inexpensive.

  In addition, since the center electrode assembly 31 and the pair of permanent magnets 41 and 41 are integrated by the adhesive layer 42, the center electrode assembly 31 is mechanically stable and becomes a robust isolator that is not deformed or damaged by vibration or impact. Such an isolator is most suitable for a portable communication device.

  Further, since the center electrodes 35 and 36 are formed of the conductor film on the main surfaces 32a and 32b of the ferrite 32, the isolator having a uniform electrical characteristic can be mass-produced stably with high accuracy in shape. Can do. In addition to this, the insulator films 37 and 38 are also formed by sintering glass powder, so that the main surfaces 32a and 32b of the ferrite 32 are flattened compared to the case where the center electrode made of a metal plate is used. It can be set as a favorable shape. As a result, the positional relationship between the ferrite 32 and the pair of permanent magnets 41 and 41 can be integrated with high parallelism.

  Also, various relay and connection electrodes are provided on the upper surface 32c and the lower surface 32d of the ferrite 32, and the electrode films on the main surfaces 32a and 32b of the ferrite 32 are connected to the relay and connection electrodes and formed on the lower surface 32d. The connection electrodes thus formed are joined to face terminal electrodes 25 a to 25 d and 25 g formed on the upper surface of the circuit board 20. As a result, the center electrodes 35 and 36 arranged on the ferrite 32 can be easily and reliably soldered to the matching circuit elements in the circuit board 20 and the input / output external connection terminal electrodes 26, 27 and 28. Can be connected to.

In such a connection, the conductor film portions on the main surfaces 32a and 32b of the ferrite 32 of the center electrodes 35 and 36 are not soldered, so that there is no risk of solder erosion. Therefore, the material used for the conductor film portion has a very low glass frit content (1
(0% or less) Silver powder or the like can be used. Since such a material has an electrical conductivity close to that of pure silver, an isolator with extremely low input loss can be obtained.

  As the material and means for joining the various connection electrodes on the lower surface 32d of the ferrite 32 to the terminal electrodes 25a to 25d, 25g on the circuit board 20, soldering is the easiest, and the electrical conductivity of the joint is good and reliable. High nature. When the thermosetting adhesive layer 42 is used in advance in the ferrite / magnet assembly 30, the adhesive layer 42 can be completely cured (cured) by solder reflow.

  In this embodiment, the circuit board 20 is a multilayer dielectric board. As a result, a circuit network such as a capacitor and an inductor can be built inside, and the miniaturization and thinning of the isolator can be achieved, and the connection between the circuit elements is performed within the substrate, so that improvement in reliability is expected. it can. Of course, the circuit board 20 does not necessarily have to be a multilayer, and may be a single layer, and a matching capacitor or the like may be externally attached as a chip type.

  Further, on the lower surface of the circuit board 20, external connection terminal electrodes 26, 27, and 28 for mounting the isolator 1 on a printed circuit board of a communication device are provided. As a result, the number of electrical joints is reduced, so that high reliability can be obtained with low loss. In addition, it is not necessary to provide another terminal component, and the lower surface position of the circuit board 20 becomes the terminal surface, so that the height can be reduced and the cost can be reduced.

(Refer to FIG. 7 and FIG. 8 for a method of manufacturing a ferrite / magnet assembly)
Next, a manufacturing method of the ferrite / magnet assembly 30 will be described. In manufacturing the ferrite / magnet assembly 30, first, the center electrode assembly 31 is manufactured, and an adhesive sheet 42 is provided on almost the entire surface as shown in FIG. 7 (may be an adhesive layer). A large number of (minimum 2 columns × 2 rows) center electrode assemblies 31 are sandwiched between a large area of the mother magnet substrates 411 and 412 to manufacture a mother substrate 413 (see FIG. 8). Thereafter, the mother substrate 413 is cut into a predetermined size, and a ferrite magnet assembly 30 is obtained in which one unit of the central electrode assembly 31 is sandwiched between the pair of permanent magnets 41 and 41.

  FIG. 8 shows the process. First, in step 1, the adhesive sheet 42 with the separator 415 is applied to the mother magnet substrate 411. In step 2, the adhesive sheet 42 is fixed on the mother magnet substrate 411. At this time, it is necessary to prevent air from entering between the adhesive sheet 42 and the mother magnet substrate 411. It is preferable to adhere the adhesive sheet 42 to the mother magnet substrate 411 with a squeegee or a roller. In addition, when the temperature of the adhesive sheet 42 and / or the mother magnet substrate 411 is raised to about 60 to 150 ° C. at the time of the close contact, the adhesiveness of the adhesive sheet 42 increases, and the adhesiveness to the mother magnet substrate 411 increases. However, it is necessary to appropriately manage the temperature and the heating time so that the thermosetting of the adhesive sheet 42 does not proceed.

  Next, in step 3, the separator 415 is peeled off, and only the adhesive sheet 42 is left on the mother magnet substrate 411. Further, in step 4, the center electrode assembly 31 is attached in a matrix on the mother magnet substrate 411 with the adhesive sheet 42. The center electrode assembly 31 may be attached individually. However, the center electrode assembly 31 is attached in advance in a matrix to another adhesive tape or mount, and is then put on the adhesive sheet 42 of the mother magnet substrate 411 all at once. It may be pasted.

  Next, in step 5, the adhesive sheet 42 is attached to the other mother magnet substrate 412. In step 6, this mother magnet substrate 412 is attached to the center electrode assembly 31 on the mother magnet substrate 411 via the adhesive sheet 42. Paste on top. Thereafter, in step 7, pressure is applied from above and below the mother magnet substrates 411 and 412 to heat them, and the adhesive sheet 42 is cured to obtain the mother substrate 413.

  Next, in step 8, the mother substrate 413 is pasted on the dicing tape 416. You may employ | adopt the method of temporarily sticking to the base plate for cutting using the foaming tape and adhesive tape which lose adhesiveness by heating, the tape which peels by washing | cleaning with a solvent, and the wax softened by temperature rising. This type of tape or base plate is for chucking (fixing) the mother substrate 413 on a dicer dicing table.

  Next, in step 9, the mother substrate 413 is cut with a dicer to obtain a unit ferrite / magnet assembly 30.

  By passing through the above process, the ferrite magnet assembly 30 which sandwiched the center electrode assembly 31 including the rectangular parallelepiped ferrite 32 with the same size permanent magnets 41 and 41 can be manufactured with high accuracy and high production efficiency. This is also effective for reducing costs. The function and effect of such a ferrite / magnet assembly 30 has been described above.

  In particular, since the mother magnet substrates 411 and 412 having a large area are used, the inclination of the magnet 41 is eliminated as compared with the case where the individual permanent magnet 41 and the ferrite 32 are bonded, and the parallelism between the permanent magnet 41 and the ferrite 32 is increased. Rise. Thus, the parallelism and uniformity of the bias magnetic field applied to the ferrite 32 is ensured, and electrical characteristics such as insertion loss are not deteriorated. Further, since there is no fear of positional deviation of the ferrite 32, it is possible not only to eliminate individual differences but also to obtain a highly reliable isolator with little aging / aging change.

(Other assembly methods)
The ferrite 32 and the permanent magnet 41 are not integrally assembled, and may be separately mounted on the circuit board 20. That is, after applying a solder paste and an adhesive to a predetermined position on the circuit board 20, the ferrite 32 (center electrode assembly 31) and the permanent magnet 41 are arranged by an automatic mounter. According to the automatic mounter, the ferrite 32 and the permanent magnet 41 can be accurately positioned and arranged in the horizontal direction. Further, in the vertical direction (height direction), the ferrite 32 and the permanent magnet 41 are mounted so that the centers thereof are substantially the same depending on the thickness of the connection electrode on the mounting surface side.

(Communication device, see FIG. 9)
Next, a mobile phone will be described as an example of the communication device according to the present invention. 9 is an electric circuit block diagram of the RF portion of the mobile phone 220, in which 222 is an antenna element, 223 is a duplexer, 231 is a transmission side isolator, 232 is a transmission side amplifier, 233 is a band pass filter for transmission side stages, 234 Is a transmission side mixer, 235 is a reception side amplifier, 236 is a reception side interstage band pass filter, 237 is a reception side mixer, 238 is a voltage controlled oscillator (VCO), and 239 is a local band pass filter.

  Here, the two-port isolator 1 can be used as the transmission-side isolator 231. By mounting the isolator 1, preferable electrical characteristics can be obtained, which contributes to a reduction in the size and height of the mobile phone.

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

  For example, if the N pole and S pole of the permanent magnets 41 and 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. The shape of the center electrode is also arbitrary, and at least one of the center electrodes may be branched into two.

It is a disassembled perspective view which shows one Example of the nonreciprocal circuit device (2 port type isolator) based on this invention. It is a perspective view which shows the center electrode assembly of the said 2 port type isolator. It is a block diagram which shows the circuit structure in the circuit board of the said 2 port type isolator. FIG. 4 is an equivalent circuit diagram illustrating a first circuit example of the two-port isolator. FIG. 4 is an equivalent circuit diagram showing a second circuit example of the two-port isolator. FIG. 3 is an elevation view schematically showing a configuration of a ferrite / magnet assembly of the two-port isolator. It is a perspective view which shows an example of the manufacturing method of the said ferrite magnet assembly. It is explanatory drawing which shows the said manufacturing method in order of a process. It is a block diagram which shows one Example of the communication apparatus which concerns on this invention. It is explanatory drawing which shows the principal part of this invention. It is explanatory drawing which shows a comparative example. It is a graph which shows the relationship between the shift | offset | difference amount of a mutual center of a ferrite and a permanent magnet, and insertion loss.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 2 port type isolator 20 ... Circuit board 25a-25g ... Terminal electrode 30 ... Ferrite magnet assembly 31 ... Center electrode assembly 32 ... Ferrite 32a, 32b ... Main surface 32c ... Upper surface 32d ... Lower surface 35 ... 1st center electrode 36 ... 2nd center electrode 35a. 36b, 36f ... Relay electrode 35b, 35c, 36d, 36h, 36i ... Connection electrode 41 ... Permanent magnet 220 ... Mobile phone P1 ... Input port P2 ... Output port P3 ... Ground port

Claims (7)

In a nonreciprocal circuit element comprising a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, a plurality of center electrodes arranged on the ferrite, and a circuit board on which a terminal electrode is formed on the surface,
A plurality of the central electrodes are formed on the main surface of the ferrite by a conductor film in a state where they are insulated from each other, and a relay electrode connected to the central electrode is formed by a conductive film on the upper surface orthogonal to the main surface. The connecting electrode connected to the center electrode is formed by a conductor film on the lower surface orthogonal to the main surface, and the connecting electrode is formed thicker than the relay electrode,
Both the ferrite and the permanent magnet have a rectangular parallelepiped shape, the main surface of the ferrite is smaller than the main surface of the permanent magnet, and each main surface on the circuit board is in a direction perpendicular to the surface of the circuit board. It is juxtaposed with the center of the main surface approximately aligned,
The connection electrode formed on the lower surface of the ferrite is electrically connected to the terminal electrode formed on the surface of the circuit board;
A nonreciprocal circuit device characterized by the above.   The nonreciprocal circuit device according to claim 1, wherein the connection electrode is formed by printing or transferring a conductor film a plurality of times.   The nonreciprocal circuit device according to claim 1, wherein the ferrite is sandwiched between two permanent magnets.   4. The nonreciprocal circuit device according to claim 3, wherein a pair of substantially permanent magnets are bonded to the opposing main surfaces of the ferrite so as to be integrated with the ferrite.   The center electrode has a first center electrode having one end electrically connected to the first input / output port and the other end electrically connected to the second input / output port, and an electrically insulated state from the first center electrode And a second center electrode having one end electrically connected to the second input / output port and the other end electrically connected to the grounding third port. The nonreciprocal circuit device according to any one of claims 1 to 4.   6. The nonreciprocal circuit device according to claim 1, wherein a matching circuit device is built in the circuit board.   A communication apparatus comprising the nonreciprocal circuit device according to claim 1.

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