JP4192883B2 - Two-port nonreciprocal circuit device and communication device - Google Patents

Description

  The present invention relates to a two-port nonreciprocal circuit device, and more particularly to a two-port nonreciprocal circuit device such as an isolator used in a microwave band and a communication device.

  For example, as this type of two-port nonreciprocal circuit device, Patent Document 1 discloses a two-port isolator in which a center electrode assembly is horizontally disposed in a horizontal direction. In this center electrode assembly, a center electrode and an insulating film are formed by printing on one main surface of the ferrite, and a connection electrode is formed on the other main surface via the side surface of the ferrite at the end of the center electrode. Yes.

  In assembling this isolator, the center electrode assembly solders and connects the connection electrode formed on the other main surface of the ferrite to other components. In addition, the center electrode formed on one main surface of the ferrite is preferably made of a material having a high conductivity and a high Ag ratio in order to reduce insertion loss.

  By the way, in recent years, in order to reduce the size of the nonreciprocal circuit element, a structure in which the center electrode assembly is vertically arranged in the vertical direction has been considered. However, when the center electrode assembly is vertically arranged in the vertical direction, the solder comes into contact with the center electrode formed on one main surface of the ferrite. For this reason, the central electrode having a high Ag ratio has a problem that Ag erosion occurs during soldering, causing problems such as increased insertion loss and electrode cutting.

Patent Document 2 discloses a two-port isolator in which a center electrode assembly is vertically arranged on a multilayer substrate. However, the center electrode of Patent Document 2 is not formed by printing, but is obtained by winding an insulation-coated conductive wire around ferrite, and the above-described problem does not occur.
JP 2002-76711 A JP 2002-26615 A

  Accordingly, an object of the present invention is to provide a 2-port non-reciprocal circuit element having a structure in which a center electrode assembly is vertically arranged in a vertical direction, and a 2-port which does not cause Ag erosion of the center electrode formed on the main surface of ferrite. An object of the present invention is to provide a type nonreciprocal circuit device and a communication device.

In order to achieve the above object, a two-port nonreciprocal circuit device according to the present invention comprises a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, and two centers comprising a conductor film disposed on the ferrite. A two-port nonreciprocal circuit device comprising: an electrode; and a circuit board having a terminal electrode formed on a surface thereof,
The ferrite has a rectangular parallelepiped shape, and the two central electrodes mainly composed of Ag intersect with each other while being insulated from each other by the insulating film, and are formed on both main surfaces of the ferrite.
A connection electrode connected to the center electrode is formed on one side surface orthogonal to both main surfaces,
An insulating film is formed on both main surfaces of the ferrite so as to cover the entire surface of the center electrode,
Ferrite is placed on the circuit board on one side perpendicular to both main surfaces,
It is characterized by.

  With the above configuration, the center electrode formed on both main surfaces of the ferrite is covered with the insulating film and is not exposed. Therefore, when the ferrite is joined to the circuit board by the solder, the solder does not come into contact with the central electrodes formed on the two main surfaces of the ferrite even if the solder wraps around the two main surfaces of the ferrite. Ag erosion does not occur.

  In the two-port nonreciprocal circuit device according to the present invention, the insulating film may be formed on the entire surface of both main surfaces of the ferrite. In addition, by forming the connection electrode on the insulating film or around the main surface where the ferrite insulating film is not formed, a solder fillet is formed between the ferrite and the circuit board to increase the bonding strength between the two. And a structure in which Ag erosion of the center electrode does not occur is obtained.

  Further, the communication device according to the present invention includes the two-port nonreciprocal circuit element, and has excellent electrical characteristics and high reliability.

  According to the present invention, the center electrode formed on both main surfaces of the ferrite is covered with the insulating film and is not exposed. Therefore, when the ferrite is joined to the circuit board by the solder, the solder is the two main electrodes of the ferrite. Even if it goes around the surface, the solder does not come into contact with the center electrode formed on both main surfaces of the ferrite, and Ag biting of the center electrode does not occur. As a result, a non-reciprocal circuit element having stable characteristics can be obtained in which problems such as increased insertion loss due to Ag erosion and electrode disconnection do not occur.

  Embodiments of a two-port 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 7]
FIG. 1 is an external view of an embodiment of a two-port nonreciprocal circuit device according to the present invention, FIG. 2 is a plan view, and FIG. 3 is an exploded perspective view. This two-port isolator 1 is a lumped constant isolator, which is roughly a metal yoke 10, a circuit board 20, a center electrode assembly 30 including a ferrite 31, and a permanent magnet for applying a DC magnetic field to the ferrite 31. It is formed with magnets 41 and 41. FIG. 1 shows a state where the isolator 1 is mounted on a substrate 50.

  The yoke 10 is made of a ferromagnetic material such as soft iron, is silver-plated, and has a frame shape surrounding the center electrode assembly 30 and the permanent magnets 41 and 41 on the circuit board 20.

  As shown in FIG. 4, the center electrode assembly 30 is formed by forming a first center electrode 35 and a second center electrode 36 that are electrically insulated from each other on main surfaces 31 a and 31 b of the microwave ferrite 31. Here, the ferrite 31 has a rectangular parallelepiped shape having a first main surface 31a and a second main surface 31b that are parallel to each other, and the first main surface 31a and the second main surface 31b have a ratio of the short side dimension to the long side dimension. (Hereinafter referred to as the shape ratio) is 1: 1.5 to 5 and the first main surface 31a and the second main surface 31b are arranged on the circuit board 20 in a substantially vertical direction. In this specification, the surfaces in contact with the long sides of the main surfaces 31a and 31b are referred to as side surfaces 31c and 31d, and the surfaces in contact with the short sides are referred to as end surfaces 31e and 31f.

  The permanent magnets 41 and 41 are disposed on the circuit board 20 so as to apply a magnetic field in a substantially vertical direction to the main surfaces 31 a and 31 b of the ferrite 31.

  As shown in FIG. 4, the first center electrode 35 is formed to be inclined at a relatively small angle with respect to the long side from the lower left to the upper right in a state where the first central electrode 35 is branched into two on the first main surface 31 a of the ferrite 31. The second main surface 31b is formed so as to be inclined at a relatively small angle with respect to the long side at the lower left in a state where the second main surface 31b branches into two via the connection electrode 35a on 31c. .

  First, the second center electrode 36 is in a state in which the 0.5th turn 36a intersects the first center electrode 35 at a relatively large angle with respect to the long side from the lower right to the upper left on the first main surface 31a. The first turn 36c is inclined leftward at a relatively large angle with respect to the long side on the second main surface 31b via the connection electrode 36b on the side surface 31c. The first central electrode 35 is formed so as to intersect with the first central electrode 35. The lower end of the first turn 36c goes around the first main surface 31a via the connection electrode 36d on the side surface 31d, and the 1.5th turn 36e is parallel to the 0.5th turn 36a on the first main surface 31a. The first center electrode 35 is formed so as to intersect with the second main surface 31b via the connection electrode 36f on the side surface 31c. The second turn 36g is also formed on the second main surface 31b 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 side surface 31d.

  The second turn 36g of the second center electrode 36 is connected to the other end of the first center electrode 35 on the second main surface 31b.

  That is, the second center electrode 36 is wound around the ferrite 31 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 31a, 31b 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 board in which predetermined electrodes are formed on a plurality of dielectric sheets, laminated, and sintered. Inside the circuit board 20, as shown in FIG. 4, matching capacitors C1, C2 The termination resistor R is built in. Terminal electrodes 25a to 25f 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. 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. The connection point 21 a is connected to one end of the first center electrode 35 through a terminal electrode 25 b formed on the upper surface of the circuit board 20 and a connection electrode 35 b formed on the side surface 31 d of the ferrite 31.

  The other end of the first center electrode 35 is connected to the termination resistor R via a connection electrode 35 c formed on the side surface 31 d of the ferrite 31 and a terminal electrode 25 c formed on the upper surface of the circuit board 20. The other end 35d of the first center electrode 35 is a connection point between the matching capacitors C1 and C2 via the connection electrode 36h formed on the side surface 31d of the ferrite 31 and the terminal electrode 25d formed on the upper surface of the circuit board 20. 21b.

  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.

  The one end connection electrode 36i (formed on the side surface 31d of the ferrite 31) of the second center electrode 36 is connected to the connection point 21c of the matching capacitor C2 via the terminal electrode 25e formed on the upper surface of the circuit board 20. ing. The connection point 21 c is connected to an external connection terminal electrode 28 formed on the lower surface of the circuit board 20. The external connection electrode 28 functions as the ground port P3. The external connection electrode 28 is also connected to the yoke 10 via terminal electrodes 25 a and 25 f formed on the upper surface of the circuit board 20.

  The circuit board 20 and the yoke 10 are integrated by soldering via terminal electrodes 25a and 25f, and the center electrode assembly 30 has various connection electrodes on the side surface 31d of the ferrite 31 connected to the terminal electrodes 25b to 25b on the circuit board 20. 25e is soldered and integrated. The permanent magnets 41 and 41 are integrated with the inner wall of the yoke 10 with an adhesive.

  The joining of the center electrode assembly 30 and the circuit board 20 will be described in more detail. As shown in FIG. 6, on the main surfaces 31a and 31b of the ferrite 31, 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, various connection electrodes are formed on the upper side surface 31c and the lower side surface 31d of the ferrite 31 by a thick conductor film.

  The center electrodes 35 and 36 are formed on the main surfaces 31a and 31b of the ferrite 31 as a thick film by printing or transfer using an electrode film material having a high ratio of Ag as a main component. Alternatively, these electrode film materials and a photosensitive material may be mixed and formed into a predetermined shape using a processing technique such as photolithography or etching.

  The insulator films 37 and 38 are made of a sintered glass powder, an organic material film such as an epoxy resin, a combination of a glass cloth and an organic material film such as an epoxy resin, etc. A thick film is formed on the entire surface of 31a and 31b. Alternatively, these materials and a photosensitive material may be mixed and formed as a thick film on the entire main surfaces 31a and 31b of the ferrite 31 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 various connection electrodes are formed as a thick film by printing or transfer using a material in which glass is added to an electrode film material containing Ag as a main component. 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.

  When mass production of the center electrode assembly 30 is performed, the first center electrode 35 made of a conductor film, the insulator film 37, the second center electrode 36 made of a conductor film, the insulator film on the main surface of the ferrite mother substrate. 38 are laminated by a method such as thick film printing. Thereafter, the ferrite mother substrate with a thick film is cut into ferrite chips of a desired size by a method such as dicing. Thereafter, various connection electrodes are formed on the side surface of the ferrite chip by a method such as thick film printing.

  As shown in FIG. 6, various connection electrodes 35b, 35c, 36d, 36h, 36i formed on the lower surface 31d of the ferrite 31 are connected to terminal electrodes 25b-25e formed on the upper surface of the circuit board 20, for example, solder 23 Joined by.

  In the two-port isolator 1 configured as described above, the ferrite 31 has principal surfaces 31 a and 31 b arranged on the circuit board 20 in a substantially vertical direction, and the permanent magnets 41 and 41 are arranged on the principal surfaces 31 a and 31 b of the ferrite 31. On the other hand, since the magnetic field is arranged on the circuit board 20 so as to be applied to the main surfaces 31a and 31b in a substantially vertical direction, in other words, the ferrite 31 and the permanent magnets 41 and 41 are arranged on the circuit board 20 in the vertical direction. Therefore, even if the permanent magnets 41 and 41 are thickened in order to obtain a large magnetic field, the height does not increase regardless of the thickness, and downsizing is achieved.

  Since the central electrodes 35 and 36 formed on both main surfaces 31 a and 31 b of the ferrite 31 are covered with the insulator film 38 and are not exposed, the ferrite 31 is joined onto the circuit board 20 by the solder 23. At this time, even if the solder 23 wraps around both the main surfaces 31 a and 31 b of the ferrite 31, the solder 23 does not contact the center electrodes 35 and 36, and Ag biting of the center electrodes 35 and 36 does not occur. As a result, the two-port isolator 1 with stable characteristics is obtained, in which there are no problems such as increased insertion loss due to Ag erosion and electrode cutting.

  Furthermore, since there is no possibility of Ag erosion, silver powder or the like having an extremely low glass frit content (10% or less) can be used as the material used for the center electrodes 35 and 36. Since such a material has an electrical conductivity close to that of pure silver, an isolator with extremely low input loss can be obtained.

  In the two-port isolator 1, as shown in FIG. 7, various connection electrodes 35 b, 35 c, 36 d, 36 h, 36 i provided on the mounting surface side of the ferrite 31 with respect to the circuit board 20 are connected to the ferrite 31. By forming so as to wrap around the insulator film 38 on the main surfaces 31a, 31b side, a solder fillet 23a is formed between the center electrode assembly 30 and the circuit board 20 to increase the joint strength between them, and A structure in which Ag erosion of the center electrodes 35 and 36 does not occur is obtained.

  In the first embodiment described above, the insulator films 37 and 38 are formed on the entire main surfaces 31 a and 31 b of the ferrite 31. However, it is not always necessary to form the entire surface of the main surfaces 31a and 31b, as long as at least the entire surfaces of the center electrodes 35 and 36 are covered. In this case, a part of the connection electrodes 35b, 35c, 36d, 36h, 36i shown in FIG. 7 is formed so as to wrap around the main surface portion of the ferrite 31 where the insulator films 37, 38 are not formed. Also good.

[Second Embodiment, FIG. 8]
Next, a mobile phone will be described as an example of the communication device according to the present invention.

  FIG. 8 is an electric circuit block diagram of the RF portion of the mobile phone 220. In FIG. 8, 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 of the first embodiment can be used as the transmission-side isolator 231. By mounting the isolator 1, it is possible to realize a highly reliable mobile phone with excellent electrical characteristics.

[Other embodiments]
The two-port 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.

  Further, although the ferrite has a rectangular parallelepiped shape, the corner may be polished by barrel polishing or the like.

The perspective view which shows one Example of the 2 port type nonreciprocal circuit device based on this invention. The top view of the 2 port type nonreciprocal circuit device shown in FIG. FIG. 2 is an exploded perspective view of the two-port nonreciprocal circuit device shown in FIG. 1. The disassembled perspective view which shows the principal part of the 2 port type nonreciprocal circuit device shown in FIG. FIG. 2 is an equivalent circuit diagram of the two-port nonreciprocal circuit device shown in FIG. 1. Sectional drawing which shows the joining state of a center electrode assembly and a circuit board. Sectional drawing which shows another joining state of a center electrode assembly and a circuit board. The block diagram which shows one Example of the communication apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 2 port type isolator 20 ... Circuit board 30 ... Center electrode assembly 31 ... Ferrite 31a, 31b ... Main surface 31c, 31d ... Side surface 35 ... 1st center electrode 36 ... 2nd center electrode 37, 38 ... Insulator film 220 …mobile phone

Claims (4)

A 2-port comprising a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, two central electrodes made of a conductor film disposed on the ferrite, and a circuit board having terminal electrodes formed on the surface Type non-reciprocal circuit element,
The ferrite has a rectangular parallelepiped shape, and the two center electrodes mainly composed of Ag intersect with each other while being insulated from each other by an insulating film, and are formed on both main surfaces of the ferrite.
A connection electrode connected to the center electrode is formed on one side surface orthogonal to the two main surfaces,
Insulating films are formed on both main surfaces of the ferrite so as to cover the entire surface of the center electrode,
The ferrite is placed on the circuit board on one side surface orthogonal to both main surfaces;
A two-port nonreciprocal circuit device characterized by the above.   The two-port nonreciprocal circuit device, wherein the insulating film is formed on the entire surface of both main surfaces of the ferrite.   3. The two-port type non-contact type according to claim 1, wherein the connection electrode is formed so as to wrap around the insulating film or a main surface portion on which the ferrite insulating film is not formed. Reversible circuit element.   A communication apparatus comprising the two-port nonreciprocal circuit device according to any one of claims 1 to 3.

Images