JP2006020051A - Non-reversible circuit element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-reversible circuit element having a microminiature, and thin shape and a low loss. <P>SOLUTION: The non-reversible circuit element includes a permanent magnet, a ferrimagnetic material which applies a DC magnetic field with the permanent magnet, a plurality of center conductors arranged to the ferrimagnetic material, a matching capacitor connected to the center conductor, and a metal casing for constituting the magnetic circuit of the DC magnetic field by the permanent magnet. The metal casing is constituted so that a loop-like current which circulates around the center conductor may not arise on the metal casing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nonreciprocal circuit device generally used as an isolator, which is used in a mobile communication system such as a mobile phone.

Conventionally, non-reciprocal circuit elements such as isolators and circulators are one type of high-frequency components used in mobile phones and the like. In general, nonreciprocal circuit elements are used for the purpose of preventing damage to power amplifiers, etc., and have a function that increases the reverse loss in the reverse direction, although the insertion loss in the signal transmission direction is small. is there.

 FIG. 5 is an exploded perspective view showing the structure of the non-reciprocal circuit device described in Patent Document 1. As shown in FIG. This non-reciprocal circuit element is electrically insulated from each other and has a central conductor portion 120 in which three central conductors 104, 105, and 106 overlapped at a predetermined angular interval are arranged on a ferrite 103, and a DC magnetic field is applied to the ferrite 103. A permanent magnet 102 for application, capacitive elements 108, 109, and 110 and a terminating resistor 111 are disposed in a metal case constituted by an upper case 101 and a lower case 112 that also serve as a magnetic yoke. It is configured. Between the upper case 101 and the lower case 112, a resin-integrated lower case 107 in which a metal material is inserted into an insulator is provided. In the resin-integrated lower case 107, capacitive elements 108, 109, 110, and terminations are provided. The resistor 111 and the central conductor 120 are housed in the recesses 113b, 113c, 113d, and 113a. In addition, external terminals for connecting to the mounting substrate are formed on the two side surfaces of the opposing outer wall of the resin-integrated lower case 107. Of the external terminals, the external terminals 115b, 115c, 115e, and 115f are ground terminals connected to the ground of the mounting board. The external terminals 115a and 115b are input / output terminals that handle high-frequency signals, and are connected to terminal electrodes 116a and 116d formed in the resin-integrated lower case 107.

The resin-integrated lower case 107 uses a thin plate of a good electrical conductor such as copper or a copper alloy, and the thin plate is punched into a required shape by press molding or the like and bent to form a heat resistant liquid crystal polymer or the like. It is formed by injection molding together with a functional resin, punching is performed again, and unnecessary portions of the thin plate are removed. The end portions of the central conductors 104, 105, and 106 are formed in a band shape, and are solder-connected to the terminal electrodes 116a and 116d, one electrode of the capacitive elements 108, 109, and 110, and one electrode of the chip resistor 111. .

FIG. 6 is an equivalent circuit of a general non-reciprocal circuit element, and the conventional example shown in FIG. 5 is also an equivalent circuit. This equivalent circuit shows an isolator having an input port P1, an output port P2, and a termination port P3 and operating at a desired frequency (center frequency). In contrast to the non-reciprocal circuit element shown in FIG. 5, the inductances L1, L2, and L3 are formed of the ferrite 103 portion around which the central conductors 104, 105, and 106 are wound, and the capacitors C1, C2, C3, and the resistance R are , Capacitance elements 108, 109, and 110, and termination resistor 111, and input port P1 and output port P2 correspond to input / output terminals 115a and 115b.

FIG. 7 is an exploded perspective view showing the structure of the non-reciprocal circuit device described in Patent Document 2. As shown in FIG. This nonreciprocal circuit device is a two-port nonreciprocal circuit device. As shown in FIG. 7, the two-port isolator 1 is roughly composed of a metal case composed of a metal upper case 4 and a metal lower case 8, a permanent magnet 9, a ferrite 20, and center electrodes 21 and 22. The center electrode assembly 13 and the laminated substrate 30 are provided.

The metal upper case 4 has a substantially box shape and includes an upper part 4a and four side parts 4b. The metal lower case 8 includes left and right side portions 8b and a bottom portion 8a. In order to form a magnetic circuit, the metal upper case 4 and the metal lower case 8 are made of, for example, a material made of a ferromagnetic material such as soft iron, and Ag or Cu is plated on the surface thereof.

The center electrode assembly 13 intersects two sets of first and second center electrodes 21 and 22 on the upper surface of the disk-shaped microwave ferrite 20 orthogonally with an insulating layer (not shown) interposed therebetween. Is arranged. The center electrodes 21 and 22 are composed of two lines. Both end portions 21a, 21b, 22a, 22b of the first center electrode 21 and the second center electrode 22 extend to the lower surface of the ferrite 20, and the end portions 21a-22b are separated from each other.

An input port 14, an output port 15, and a ground port 16 are provided at both ends of the multilayer substrate 30, respectively. The input port 14 is electrically connected to the capacitor electrode in the multilayer substrate, and the output port 15 is electrically connected to the capacitor electrode in the multilayer substrate. The earth port 16 is electrically connected to a ground electrode in the multilayer substrate. The multilayer substrate 30 has matching capacitors C1 and C2 and a resistor R therein.

The permanent magnet 9 is fixed to the ceiling of the metal upper case 4 with an adhesive. By electrically connecting the end portions 21 a to 22 b of the center electrodes 21 and 22 of the center electrode assembly 13 to the center electrode connection electrodes 51 to 54 formed on the surface of the multilayer substrate 30 with solder 80. The center electrode assembly 13 is mounted on the multilayer substrate 30. The center electrodes 21 and 22 and the center electrode connection electrodes 51 to 54 may be soldered efficiently to the laminated substrate 30 in the mother board state.

The multilayer substrate 30 is placed on the bottom portion 8a of the lower metal case 8, and the ground electrode disposed on the lower surface of the multilayer substrate 30 is connected and fixed to the bottom portion 8a with solder. Thereby, the earth port 16 is easily electrically connected to the bottom portion 8a. The metal lower case 8 and the metal upper case 4 constitute a metal case by joining the side portions 8b and 4b with solder or the like, and also function as a yoke. That is, the metal case forms a magnetic path that surrounds the permanent magnet 9, the center electrode assembly 13, and the laminated substrate 30. The permanent magnet 9 applies a DC magnetic field to the ferrite 20.

An electric equivalent circuit diagram of the two-port isolator 1 is shown in FIG. One end 21 a of the first center electrode 21 is electrically connected to the input port 14, and the other end 21 b is electrically connected to the output port 15. One end 22 a of the second center electrode 22 is electrically connected to the output port 15, and the other end 22 b is electrically connected to the ground port 16. The parallel RC circuit including the matching capacitor C1 and the resistor R is electrically connected between the input port 14 and the output port 15. The matching capacitor C <b> 2 is electrically connected between the output port 15 and the earth port 16.
Japanese Patent Laid-Open No. 11-205011 JP 2004-15430 A

As mobile phones become smaller and more multifunctional, nonreciprocal circuit elements are also strongly required to be smaller. The embodiment of Patent Document 1 discloses a non-reciprocal circuit element having an outer dimension of 5 mm × 5 mm × 2 mm, but at present, a small non-reciprocal circuit element having an outer dimension of 4 mm × 4 mm × 1.7 mm is disclosed. Non-reciprocal circuit elements having outer dimensions of 3.2 mm × 3.2 mm × 1.6 mm have also been proposed.
In such miniaturization, the 2-port isolator as shown in Patent Document 2 has a smaller number of parts than the conventional 3-port isolator, and is considered advantageous for miniaturization. Therefore, the present inventor tried to configure the two-port isolator in a very small size. However, there is a problem that the center frequency and the insertion loss characteristic cannot be obtained at a desired frequency.

Therefore, an object of the present invention is to provide a novel means for obtaining the center frequency and insertion loss characteristics at a desired frequency.

A first aspect of the present invention is a permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, and a matching capacitor connected to the center conductor And a metal case for constituting a magnetic circuit of a DC magnetic field by the permanent magnet, and the metal case does not generate a loop current around the central conductor on the metal case. This is a non-reciprocal circuit device configured.
According to a second aspect of the present invention, there is provided a permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, and a matching capacitor connected to the center conductor And a metal case for constituting a DC magnetic field magnetic circuit by the permanent magnet, wherein the metal case is substantially in the same direction as the direction of the center conductor connected to the ground electrode among the center conductors. The non-reciprocal circuit device is configured so that a loop current that circulates is not generated on the metal case.
According to a third aspect of the present invention, there is provided a permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, and a matching capacitor connected to the center conductor And a metal case for constituting a DC magnetic field magnetic circuit by the permanent magnet, wherein the metal case is configured by combining a plurality of case members, and at least one case among the case members This is a non-reciprocal circuit element in which members are joined by an insulating material and conductivity between the case members is hindered.
According to a fourth aspect of the present invention, there is provided a permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, and a matching capacitor connected to the center conductor And a metal case for constituting a magnetic circuit of a DC magnetic field by the permanent magnet, the metal case is divided into an upper case and a lower case, and the lower case has at least a pair of opposing side wall portions. And the side wall portion is combined with the upper case, and one of the pair of opposing side wall portions is electrically connected to the upper case, and the other side wall portion is electrically connected to the upper case. This is a non-reciprocal circuit device configured to prevent electrical conduction.

In the present invention, as the central conductor, one end is electrically connected to the input terminal, the other end is electrically connected to the output terminal, and one end is electrically connected to the output terminal, Preferably, the other end has a second central conductor electrically connected to the ground terminal. Further, the side wall portion soldered to the upper case of the lower case is on the other end side of the second central conductor, and the side wall portion not soldered to the upper case of the lower case is the second side conductor. It is preferable that it is on the one end side of the central conductor. Further, the configuration in which the loop current does not occur on the metal case is sufficient if the loop current does not flow in a DC manner.

According to the present invention, desired characteristics can be obtained at a desired frequency, and in particular, an ultra-compact and thin non-reciprocal circuit element that has a low loss can be provided.

FIG. 1 is an explanatory view showing the structure of a non-reciprocal circuit device (Example 1) according to the present invention. The non-reciprocal circuit device according to the present invention includes a ferrimagnetic body 210 and first and second center conductors 221 and 222 that are disposed close to the ferrimagnetic body 210 and intersect each other in an electrically insulated state. A resin-integrated lower case 280 formed with a central conductor 220, a multilayer substrate 250 that forms a matching capacitor for the first and second central conductors, and an input terminal and an output terminal that are electrically connected to the multilayer substrate 250. And a permanent magnet 240 that supplies a DC magnetic field to the ferrimagnetic body 210 and an upper case 270 that houses the permanent magnet 240 and forms a magnetic circuit.

In order to form a magnetic circuit, the upper case 270 shown in FIG. 1 is formed of a material made of a ferromagnetic material such as soft iron, and the surface thereof is plated with silver or copper. Further, the upper case 270 functions as a magnetic yoke together with a metal plate insert-molded in the resin-integrated lower case 280. That is, the upper case and the metal plate of the resin-integrated lower case form a magnetic path (magnetic circuit) that surrounds the permanent magnet 240, the center electrode assembly 230, and the laminated substrate 250.
Further, since the upper case 270 is made of metal, it has a function as an external case that forms a magnetic circuit and accommodates and holds other components.
Further, the surface of the upper case 270 is a metal or alloy containing at least one of silver, copper, gold, and aluminum, and has an electrical resistivity of 5.5 μΩcm or less, preferably 3.0 μΩcm, more preferably 1.8 μΩcm or less. It is preferable to form a highly conductive metal film. The thickness of the metal film is 0.5 to 25 μm, preferably 0.5 to 10 μm, and more preferably 1 to 8 μm. The magnetic yoke also functions as a ground, but with this configuration, the metal film serves as a path to the ground terminal for high-frequency current, thereby improving the transmission efficiency of high-frequency signals and suppressing mutual interference with the outside. Loss can be reduced.

The resin-integrated lower case 280 shown in FIG. 1 has a conductive thin plate of about 0.1 mm, and includes an input external electrode IN, an output external electrode OUT, and a ground terminal GND using the conductive thin plate by insert molding. Is. The laminated substrate 250 is accommodated in the cavity of the resin-integrated lower case 280, and the ground electrode GND, the input external electrode IN, and the output external electrode OUT of the multilayer substrate 250 are connected to the input external electrode IN of the resin-integrated lower case 280. The output external electrode OUT and the ground electrode GND are electrically connected by soldering.

For the frames 281a and 281b of the resin-integrated lower case 280, a metal material, for example, a JIS: PB material having a thickness of about 0.15 mm is used, and a silver plating having a thickness of 2 to 4 μm is formed on the copper base plating 1 to 3 μm. Applied to improve high frequency characteristics. The frames 281a and 281b are connected on the lower side and have a so-called U-shape, and together with the upper case, form a magnetic path that surrounds the permanent magnet 240, the central electrode assembly 230, and the multilayer substrate 250. The case is made up. The frames 281a and 281b, the input external electrode IN, and the output external electrode OUT are each electrically insulated from the resin base 282 and insert-molded. The frames 281a and 281b and the ground electrode GND are formed of the same metal plate and connected to each other.

FIG. 2 shows a perspective view of the first embodiment in which the upper case 270 is combined with the resin-integrated lower case 280. In the first embodiment, the positions of the frames 281a and 281b of the resin-integrated lower case 280 are accurately matched by the notches 271a to 271d formed at the four corners of the upper case 270. Then, the mating surface 270a of one side wall (frame 281a) of the lower case and the upper case 270 is soldered, and the other side wall (frame 281b) of the lower case and the upper case 270 are mated on the opposite surface side. The surface is fixed not by soldering but by an adhesive. This adhesive is insulative, and the upper case and the lower case are not electrically connected on the bonded side.

In the nonreciprocal circuit device according to the first embodiment, a matching capacitor is built in the multilayer substrate 250. However, since it is not ready to configure a capacitor with a precise capacitance value in the multilayer substrate 250, the matching capacitor formed in advance on the multilayer substrate 250 is made smaller than the design value, and the capacitance value of the completed multilayer substrate 250 is reduced. After the confirmation, the insufficient capacitance value is corrected by the chip capacitors 261 and 262.
As another method for adjusting the capacitance value, a method of trimming an electrode pattern or the like formed on the laminated substrate 250 and finely adjusting the capacitance value can be used.
Of course, if adjustment is not necessary, it may be configured only by a matching capacitor formed on the multilayer substrate 250.

In the center conductor assembly 230 of the first embodiment, two sets of first and second center conductors 221 and 222 are orthogonal to the surface of a rectangular ferrimagnetic body 210 with an insulating layer (not shown) interposed therebetween. Are arranged so that they intersect.
One end portions 221 a and 222 a of the first central conductor 221 and the second central conductor 222 are open ends on the side surfaces of the ferrimagnetic body 210, and the other end portions are integrally extended to the lower surface of the ferrimagnetic body 210. Yes. One end 221a of the first center conductor 221 is electrically connected to the input terminal IN, and the other end is electrically connected to the output terminal OUT.

Each of the first and second center conductors 221 and 222 can be composed of different conductors. However, when the first and second center conductors 221 and 222 are integrally formed of a copper plate or the like, the assemblability is improved. In the first embodiment, the first and second center conductors 221 and 222 are integrally formed of an L-shaped copper plate, the first center conductor 21 is formed of three parallel conductors, and the second center conductor 222 is formed. Is formed of one conductor. As a result, it has been found from the Smith chart that the inductance for the high-frequency current in the through direction is reduced to reduce the insertion loss, and the reflection loss is reduced by relatively increasing the inductance in the reverse direction.
The central conductor 220 has a copper plate thickness of 30 μm, and a semi-glossy silver plating of 1 to 4 μm is applied to reduce the loss due to the skin effect at high frequencies, and the total thickness is 35 μm.

In the present invention, the ferrimagnetic material 210 may be disk-shaped, but if the rectangular ferrimagnetic material 210 shown in Example 1 is used, the volume of the ferrimagnetic material can be increased. The circuit element characteristics can be utilized to the maximum. By making the permanent magnet 240 rectangular, the magnetic flux density of the permanent magnet 240 can be effectively utilized up to the end.
That is, as shown in the first embodiment, by using a rectangular ferrimagnetic body 210, the length of the central conductors 221 and 222 wound around the ferrimagnetic body 210 can be increased as much as possible. The inductances 221 and 222 can be increased, and can be applied to lower frequencies. In addition, the rectangular ferrimagnetic body 210 can reduce the dead space at the time of mounting as compared with the disk-shaped ferrimagnetic body, and thus can be made more compact.

The ferrimagnetic material 210 of Example 1 is a ferrite having a garnet structure, and YIG (yttrium, iron, garnet) or the like is used. Further, it is possible to use YIG in which part of Y is replaced with Gd, Ca, V, etc. and part of Fe is replaced with Al, Ga, or the like. It is not limited to YIG, and any magnetic material can be used as long as it is a material that functions as a non-reciprocal circuit element with respect to a DC magnetic field from the permanent magnet 240.

The center conductor assembly 230 of the first embodiment has a shape in which the ferrimagnetic body 210 is wrapped with a first center conductor 221 and a second center conductor 222 that are electrically insulated from each other. By receiving a DC magnetic field from the permanent magnet 240, it functions as an inductance, and has inherent inductances Lin and Lout, respectively.

The permanent magnet 240 according to the first embodiment causes the first central conductor 221 and the second central conductor 222 to function as specific inductances Lin and Lout by applying a DC magnetic field to the central conductor assembly 230.

As the permanent magnet 240, a ferrite magnet (SrO · nFe 2 O 3) is the cheapest and has good compatibility with the ferrimagnetic material 210. More preferably, a part of Sr and / or Ba is substituted with an R element (R element is at least one kind of rare earth element including Y), and a part of Fe is replaced with an M element (M element is Co, Mn, A ferrite magnet having a magnetoplumbite type crystal structure substituted with at least one selected from the group consisting of Ni and Zn is better. Compared to a conventional ferrite magnet (SrO.nFe2O3), it has a higher magnetic flux density, so that the lumped constant type nonreciprocal circuit device can be made smaller and thinner.

FIG. 3 is an explanatory diagram showing a laminated structure of the laminated substrate 250 shown in the first embodiment. The multilayer substrate 250 is composed of six layers of dielectric sheets S1 to S6. Electrode patterns are printed on the dielectric sheets S1 to S6 with a conductive paste, and each layer of the dielectric sheets S1 to S6 is electrically connected via via holes Vhg1 to Vhg6, Vhi1 to Vhi6, Vho1 to Vho6 filled with the conductive paste. Connected to. The via holes Vhg1 to Vhg6 are via holes for electrically connecting the ground electrode pattern to the ground terminal GND. The via holes Vhi1 to Vhi6 are via holes for electrically connecting the ground electrode pattern to the input external electrode IN. The via holes Vho1 to Vho6 are via holes for electrically connecting the ground electrode pattern to the output external electrode OUT.

The function of the electrode pattern will be described for each layer of the dielectric sheets S1 to S6.
An electrode 251 for adjusting the capacitor Cf in the equivalent circuit of FIG. 4 is formed on the dielectric sheet S1. The capacitor Cf can be adjusted by trimming the electrode 251. The electrode 252 is an electrode for adjusting the capacitor Ci.
An electrode 253 for forming the capacitor Cf is formed on the dielectric sheet S2, and the capacitor Cf is formed between the electrode 251 of the dielectric sheet S1 and the electrode 255 of the dielectric sheet S3. In addition, an electrode 254 for forming the capacitor Ci is formed, and the capacitor Ci is formed between the electrode 252 of the dielectric sheet S1.
An electrode 255 is formed on the dielectric sheet S3, and a capacitor Cf is formed between the electrode 253 of the dielectric sheet S2.
An electrode 256 is formed on the dielectric sheet S4, and a capacitor Ci is formed between the electrode 255 of the dielectric sheet S3 and the electrode 257 of the dielectric sheet S5.
An electrode 257 is formed on the dielectric sheet S5, and a capacitor Ci is formed between the electrode 256 of the dielectric sheet S4 and a capacitor Cf is formed between the electrode 258 of the dielectric sheet S6.
An electrode 258 is formed on the dielectric sheet S6, and a capacitor Cf is formed between the electrode 257 of the dielectric sheet S5. The electrode 259 constitutes the inductance L of the equivalent circuit shown in FIG.
The above dielectric sheets S1 to S6 are electrically connected by via holes Vhg1 to Vhg6, Vhi1 to Vhi6, Vho1 to Vho6, and form an equivalent circuit shown in FIG.

  3 is a perspective view of the multilayer substrate 250 as viewed from the back side, and the input external terminal IN and the output external terminal OUT are arranged with the ground electrode GND interposed therebetween.

The material of the multilayer substrate 250 will be described. As the material composition of the ceramic used for the dielectric sheets S1 to S6 in the production of the multilayer substrate 250 substrate, any low-temperature sintered ceramic material that can be co-fired with a conductor paste such as silver, so-called LTCC ceramic, can be used.
More preferably, when Al, Si, Sr, and Ti as main components are converted into Al2O3, SiO2, SrO, and TiO2, respectively, 10 to 60 wt% in terms of Al2O3, 25 to 60 wt% in terms of SiO2, and 7 in terms of SrO. 5 to 50 wt%, 20 wt% or less (including 0) in terms of TiO 2, and at least one of the group of Bi, Na, K, and Co as Bi 2 O 3 equivalent to the main component 100 wt% 0.1 to 5 wt% in terms of Na2O, 0.1 to 5 wt% in terms of K2O, 0.1 to 5 wt% in terms of CoO, and Cu, Mn, Ag At least one of them contains 0.01 to 5 wt% in terms of CuO, 0.01 to 5 wt% in terms of MnO2, 0.01 to 5 wt% of Ag, and other inevitable impurities. The mixture was calcined at 700 ° C. to 850 ° C., a dielectric ceramic composition comprising finely divided particles having an average particle diameter of 0.6~2μm by pulverizing it.
Accordingly, the multilayer substrate 250 can be integrally sintered using a metal material having high conductivity such as silver, copper, or gold as the internal electrode. As a result, it is possible to configure a non-reciprocal circuit device with extremely low loss by using an internal electrode that uses a high Q value of a dielectric material and suppresses loss due to electric resistance.

A method for manufacturing the multilayer substrate 250 will be described.
The laminated substrate 250 is manufactured by a normal LTCC (Low Temperature Cofiring) method in which an electrode pattern is printed on a dielectric green sheet with a conductive paste, and the via hole is filled with the conductive paste and then laminated. it can.
More preferably, according to the constrained firing method, a small laminated substrate with a small firing strain can be obtained. That is, after firing by sandwiching the top and bottom of a shrinkage suppression sheet that suppresses firing shrinkage in the substrate plane direction (XY direction) of the laminated substrate without firing under the firing conditions of the laminated substrate (especially at a firing temperature of 1000 ° C. or less). The multilayer substrate 250 can be obtained by removing the shrinkage suppression sheet.
As the material of the shrinkage suppression sheet, alumina powder, a mixed material of alumina powder and stabilized zirconia powder, or the like can be used.

The chip capacitors 261 and 262 of Example 1 will be described. As the chip capacitors 261 and 262, commercially available chip capacitors whose capacitance values of about 1 to 3 pF are accurately managed can be used, and the insertion loss frequency and the isolation frequency can be adjusted to the design values with high accuracy. .

FIG. 4 is an equivalent circuit diagram of the first embodiment. This equivalent circuit diagram will be described. A resistor R serving as a termination resistor is connected between the input terminal In corresponding to the input external electrode IN and the output terminal Out corresponding to the output external electrode OUT, and the nonreciprocal circuit functions as an isolator. The resistor R is mounted with a normal chip resistor. A capacitor Ci that controls the isolation frequency is connected between the input terminal In and the output terminal Out. Further, an inductance Lin formed by application of a DC magnetic field of the permanent magnet 240 between the first central conductor 221 and the ferrimagnetic material 210 is also connected. On the output terminal Out side of the inductance Lin, an inductance Lout formed by application of a DC magnetic field of the permanent magnet 240 with the second central conductor 222 and the ferrimagnetic body 210 is connected. In many cases, the other end of the inductance Lout is directly connected to the ground. In the embodiment shown in FIG. 2, the other end of the inductance Lout is connected to the inductance Lout by providing the dielectric sheet S6 with the electrode 259 that forms the inductance L. It is grounded via Thereby, the attenuation pole for attenuating the harmonics (2f, 3f) of 2 times and 3 times can be adjusted. A capacitor Cf is connected between the output terminal Out and the ground. Thereby, the insertion loss frequency is controlled.

According to Example 1, an ultra-small isolator of 3.2 mm × 3.2 mm × 1.5 mm (height) could be configured. The frequency used is 830 to 840 MHz.

The configuration is the same as that of the first embodiment, and the mating surface 270a of one side wall (frame 281a) of the lower case and the upper case 270, and the other side wall (frame 281b) of the lower case facing the opposite side Example 2 in which both of the mating surfaces with the upper case 270 are fixed by an adhesive without soldering, the mating surface 270a between one side wall (frame 281a) of the lower case and the upper case 270, and the facing surfaces thereof. Comparative Example 1 was prepared in which both the other side wall (frame 281b) of the lower case on the surface side and the mating surface of the upper case 270 were soldered.

The respective characteristic diagrams of Example 1, Example 2 and Comparative Example 1 are shown in FIGS. 9 shows the first embodiment, FIG. 10 shows the second embodiment, and FIG. 11 shows the first comparative example, and shows the insertion loss, isolation, return loss (IN), and return loss (OUT), respectively.
Table 1 shows numerical values corresponding to FIGS.

As shown in FIGS. 9 to 11 and Table 1, in Examples 1 and 2 of the present invention, good results are obtained at a target frequency of 830 to 840 MHz. On the other hand, in the comparative example, the insertion loss characteristic is particularly deteriorated, the peak frequency is shifted, and the shift of the peak frequency and the characteristic value are deteriorated in other characteristics. From this result, it can be seen that the structure of the present invention can provide a non-reciprocal circuit device that matches the target frequency and has low loss.

  In Examples 1 and 2, almost the same good characteristics are obtained, but in the case of Example 1, the upper case is in a state connected to the ground electrode and is not easily affected by the outside at the time of mounting or the like. Conceivable. Therefore, the structure of Example 1 (the structure in which the upper case is connected to the ground electrode) is considered preferable to the structure in which the upper case of Example 2 is not connected to the ground electrode.

With the structure of FIG. 1, the function and effect of the present invention will be described. The conventional case structure is divided into an upper case and a lower case in the same manner as in FIG. 1, and the joint portions of the upper case and the lower case are soldered. That is, the joining structure of the conventional case was the same as that of the comparative example. However, in the case of this comparative example, as shown above, desired characteristics could not be obtained at the target frequency. Considering this factor, the overall size and thickness have been reduced, and the center conductor and the case are very close to each other, and an induced electromotive force is generated in the case due to the current flowing through the center conductor. It becomes easier, and it is thought that the influence of this induced electromotive force appears. In Example 1, the distance between the center conductor and the upper case is about 0.43 mm.

The influence of the induced electromotive force generated in this case will be described with reference to FIG. When a current 301 flows through the center conductor 222, an induced electromotive force 302 is generated in the case by the generated high-frequency magnetic field. The induced electromotive force 302 causes an induced current (a loop current that circulates around the center conductor) 304 to flow in the case, and the high-frequency magnetic field 303 generated by the induced current 304 weakens the high-frequency magnetic field of the center conductor 222. It is considered that the inductance Lout of 222 is reduced, the characteristic shifts to the high frequency side, and the loss increases.

Accordingly, it is considered that the influence on the central conductor 222 can be eliminated or reduced by adopting a structure in which the induced current (loop current that circulates so as to surround the central conductor) 304 does not occur, and the present invention has been achieved. It is a thing.
That is, in Example 1, the upper case and the lower case are connected at two locations (two side surfaces), but on the one hand, they are conductive by soldering, but on the other hand they are fixed by the adhesive, so they are conductive. The induction current (the loop current that circulates so as to surround the central conductor) 304 is not generated (the structure in which the loop current does not flow in a direct current). Further, in the second embodiment, the upper case and the lower case are joined only by the adhesive, so that the induced current (loop current that circulates so as to surround the central conductor) 304 is not generated. Thus, desired characteristics can be obtained at a desired frequency, and an ultra-small and thin non-reciprocal circuit device can be configured.

Examples of the present invention are not limited to Examples 1 and 2, and various configurations are conceivable. That is, it is only necessary that the induced current (loop current that circulates around the central conductor) 304 does not flow or can hardly flow.

  For example, a slit is formed in the metal frame so that the induced current does not flow or does not flow easily in the resin-integrated lower case, such as the resin-integrated lower case shown in the perspective view and the sectional view in FIG. May be. A slit 283 is provided in the frame (lower part) 281c of the resin-integrated lower case, and the slit 283 is preferably filled with resin so as to be continuous with the resin base 282. As a result, even when the frames (side walls) 281a and 281b are electrically cut and the mating surfaces 270a and 270b with the upper case 270 are connected by soldering, the induced current does not flow or does not flow easily. It becomes.

  As another structure, it can also be realized by interposing a magnetic material having high insulation, for example, soft ferrite, at the joint between the upper case and the resin-integrated lower case. FIG. 14 is a perspective view of a non-reciprocal circuit device using this structure, and FIG. 15 is an exploded perspective view thereof. Magnetic materials 290a and 290b having a relatively large specific resistance, such as Ni—Zn ferrite and Mn—Zn ferrite, are disposed on the surface end of the resin case frame (lower part) 281c. A structure in which the bent tip portions 276a and 276b of the upper case 275 are joined and incorporated to exhibit the insulating property, the induced current does not flow or does not flow without providing a magnetic gap, and an internal magnetic field is maintained. I was able to.

It is a disassembled perspective view of one Example of the nonreciprocal circuit device based on this invention. It is a perspective view of one Example of the nonreciprocal circuit device based on this invention. It is a figure which shows one Example of the laminated substrate used for the nonreciprocal circuit device based on this invention. It is an equivalent circuit diagram with respect to one Example of the nonreciprocal circuit device based on this invention. It is a disassembled perspective view of a 1st prior art example. It is an equivalent circuit diagram of a first conventional example. It is a disassembled perspective view of a 2nd prior art example. It is an equivalent circuit diagram of a second conventional example. 2 is a characteristic diagram of Example 1. FIG. FIG. 6 is a characteristic diagram of Example 2. It is a characteristic view of a comparative example. It is explanatory drawing of an effect | action of this invention. It is the perspective view and sectional drawing of the resin integrated lower case used for the nonreciprocal circuit device based on the other Example of this invention. It is a perspective view of the nonreciprocal circuit device according to another embodiment of the present invention. It is a disassembled perspective view of the non-reciprocal circuit device according to another embodiment of the present invention.

Explanation of symbols

210 Ferrimagnetic body 220 Center conductor 221 First center conductor 222 Second center conductor 230 Center conductor assembly 240 Permanent magnet 250 Multilayer substrate 261, 262 Chip capacitor 270, 275 Upper case 280 Resin integrated lower case 281a, 281b Frame (Side wall)
281c frame (bottom)
282 Resin base 283 Slit 290 Highly insulating magnetic material 301 Current 302 Inductive electromotive force 303 High frequency magnetic field 304 Inductive current (a loop current that circulates around the central conductor)

Claims (5)

A permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, a matching capacitor connected to the center conductor, and a DC by the permanent magnet It has a metal case for configuring the magnetic circuit of the magnetic field,
The non-reciprocal circuit device, wherein the metal case is configured such that a loop current that circulates around the central conductor does not occur on the metal case. A permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, a matching capacitor connected to the center conductor, and a DC by the permanent magnet It has a metal case for configuring the magnetic circuit of the magnetic field,
The metal case is configured such that a loop current that circulates in substantially the same direction as the center conductor connected to the ground electrode among the center conductors does not occur on the metal case. A nonreciprocal circuit device characterized by the above. A permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, a matching capacitor connected to the center conductor, and a DC by the permanent magnet It has a metal case for configuring the magnetic circuit of the magnetic field,
The metal case is configured by combining a plurality of case members, and among the case members, at least one case member is joined by an insulating material, and conductivity between the case members is hindered. A non-reciprocal circuit device characterized by comprising: A permanent magnet, a ferrimagnetic body to which a DC magnetic field is applied by the permanent magnet, a plurality of center conductors disposed on the ferrimagnetic body, a matching capacitor connected to the center conductor, and a DC by the permanent magnet It has a metal case for configuring the magnetic circuit of the magnetic field,
The metal case is divided into an upper case and a lower case, and the lower case has at least a pair of opposed side wall portions, and is combined with the upper case by the side wall portions, and the pair of opposed side walls. The non-reciprocal circuit device is characterized in that one of the side walls is electrically connected to the upper case, and the other side wall is not electrically connected to the upper case. As the center conductor, one end is electrically connected to the input terminal, the other end is electrically connected to the output terminal, one end is electrically connected to the output terminal, and the other end is grounded. The nonreciprocal circuit device according to claim 1, further comprising a second central conductor electrically connected to the terminal.

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