JP4329079B2 - 2-port nonreciprocal circuit device - Google Patents

Description

  The present invention relates to a two-port nonreciprocal circuit device used in a high-frequency wireless communication device such as a mobile phone.

  Miniaturization is strongly demanded in the portable radio communication equipment market represented by mobile phones, and miniaturization is inevitably required for parts used in radio communication equipment. A lumped-constant nonreciprocal circuit element used in a high-frequency circuit such as a wireless communication device is no exception. Conventionally, in a lumped-constant nonreciprocal circuit element, the height tends to be higher than that of an electronic circuit component arranged in the periphery due to a structure in which metal cases, permanent magnets, and microwave magnetic bodies are stacked. For this reason, in the design of portable wireless communication devices, it is required to unify the height with the peripheral parts, and among the miniaturization, particularly low height is strongly demanded.

Among these nonreciprocal circuit elements, a structure called a 2-port nonreciprocal circuit element is proposed in Patent Document 1. FIG. 6 shows a circuit diagram thereof. As a feature of this structure, good reflection loss and insertion loss can be obtained over a wide band. FIG. 7 shows a magnetic rotor composed of a center electrode and a microwave magnetic material. The center electrodes intersect with each other on the top surface of the microwave magnetic body, and at least a part of the end of the center electrode reaches the bottom surface of the microwave magnetic body along the side surface of the microwave magnetic body. As can be seen from FIG. 6, one of the structural features of this two-port nonreciprocal circuit device is that there is a central conductor that is not grounded at either end . Therefore, this magnetic rotor cannot be arranged directly on the metal case at the ground potential, and it is necessary to insulate the center electrode end from the metal case by some method.

JP 2004-15430 A Japanese Patent Laid-Open No. 10-41706

  In such a two-port non-reciprocal circuit device structure, if a ceramic laminate having a plurality of matching capacitors built therein is used for miniaturization, the conventional structure has difficulty. For example, as described in Patent Document 2, in a structure in which a hole is formed in a ceramic laminate in accordance with a microwave magnetic body, an electrode serving as a common node portion cannot be disposed below the garnet. This is because if a common node is placed below the garnet, it will contact the metal case and short circuit.

  Further, as described in Patent Document 1, there is also a method of arranging a microwave magnetic body on a ceramic laminate. However, in such a structure, a certain thickness is required to maintain the mechanical strength so that the ceramic laminate is not broken. Therefore, it becomes disadvantageous when the height is lowered.

  An object of the present invention is to overcome the above-described problems and to make the two-port nonreciprocal circuit device have a low profile while maintaining good performance.

A two-port nonreciprocal circuit device according to the present invention includes a ceramic laminate including two central conductors, a microwave magnetic body, a permanent magnet, an insulating sheet, and a plurality of matching capacitors. Is provided so as to intersect with the upper surface of the microwave magnetic body, and at least a part of an ungrounded electrode connected to one end of the central conductor is disposed below the microwave magnetic body, and the ceramic The laminated body is arranged on a side of the microwave magnetic body on the insulating sheet.
As described above, the ceramic laminate is disposed on the insulating sheet to the side of the microwave magnetic body, so that the thickness of the ceramic laminate does not affect the overall dimensions of the non-reciprocal circuit element even if the ceramic laminate is thickened. Therefore, it is easy to reduce the height.

In the two-port nonreciprocal circuit device of the present invention, the insulating sheet is preferably formed with flexibility.
Thus, by giving flexibility to the insulating sheet, it is possible to absorb the twist of the substrate on which the nonreciprocal circuit element is mounted, and to avoid problems such as cracking and chipping.

In the two-port nonreciprocal circuit device of the present invention, a connection line is formed on the surface of the insulating sheet, and electrical connection between the ceramic laminate and the central conductor is ensured by the line.
Thus, by forming the connection line on the surface of the insulating sheet, the electrical connection between the ceramic laminate and the central conductor can be secured stably and without an increase in an extra wiring process.

In the two-port nonreciprocal circuit device of the present invention, the insulating sheet may have through holes that electrically connect both surfaces thereof.
Thus, by providing the through hole for connecting both surfaces of the insulating sheet, it is possible to easily connect one end of the central conductor to an external circuit.
Furthermore, it is preferable that the two-port nonreciprocal circuit device includes a metal case, and a stabilization line electrically connected to the metal case is formed on the lower surface of the insulating sheet.

In the two-port nonreciprocal circuit device of the present invention, the intersection angle between the first center conductor and the second center conductor may be 95 degrees or more and 113 degrees or less.
In this way, by making the angle between the first center conductor and the second center conductor to be 95 degrees or more and 113 degrees or less, the impedance mismatch caused by the stray capacitance between the common node and the metal case is improved, It is possible to maintain good matching conditions.

The two-port nonreciprocal circuit device of the present invention may have a structure in which a grounding connection pad is provided on the upper surface of the ceramic laminate, and one end of the second central conductor is connected to the connection pad.
Thus, by providing a grounding connection pad on the upper surface of the ceramic laminate, and connecting one end of one of the center conductors to the connection pad, the second center conductor can be effectively applied to the microwave magnetic body. The number of turns can be increased and the electrical characteristics can be improved.

  According to the two-port nonreciprocal circuit device of the present invention, it is possible to achieve a low profile while having the characteristics of wideband reflection loss and insertion loss.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an exploded perspective view showing a first embodiment of a two-port nonreciprocal circuit device according to the present invention. FIG. 2 shows the back side of the insulating sheet used in the first embodiment shown in FIG. FIG. 3 is a perspective view after assembly of the first embodiment. However, the upper metal case is omitted in order to display the inside.

  In the figure, reference numeral 1 denotes a metal case that also serves as a magnetic yoke for forming a closed magnetic circuit, and the surface thereof is silver-plated to reduce loss. Reference numeral 2 is an insulating sheet using a polyimide resin, and a copper foil (about 5 μm) is pasted on the upper surface and then etched to connect the center electrode end, the input / output terminal, and the lower electrode of the ceramic laminate. The connecting lines 3a and 3b are formed.

  Insulation sheet 2 uses a thin film with a thickness of 25 μm to reduce the height of the non-reciprocal circuit element, and has both insulation and flexibility. In addition, in order to suppress dielectric loss due to high frequencies, the dielectric loss tangent is It is necessary to use a small material. In this embodiment, polyimide is used as such a material. In addition, as shown in FIG. 2, a stabilization line 3c is formed on the lower surface of the insulating sheet to stabilize the size of the stray capacitance that the connection lines 3a and 3b inevitably form with the metal case 1. Has been. The stabilization line 3c is electrically connected to the metal case 1 by solder or the like.

  By providing the stabilization line 3c in this way, the connection lines 3a and 3b do not form a stray capacitance directly with the metal case 1, and a stray capacitance is formed with the stabilization line 3c. Will come to be. Therefore, even if a gap is formed between the insulating sheet 2 and the metal case 1, the stray capacitance of the connection lines 3a and 3b is not greatly changed, and stable characteristics can be obtained.

4a provided on the insulation sheet 2, 4b, 4c are through holes, 4a, 4b is provided for connecting the connection terminals 11a, 11 b of the external circuit connection line 3a, the 3b, the through hole 4c is It is provided to connect the metal case 1 and the electrode 3d. The electrode 3d is further connected to a ground electrode provided for supplying a ground potential to the lower part of the ceramic laminate.

Reference numeral 5 denotes a microwave magnetic material, and here, a garnet material having a saturation magnetization of 0.09 T, a diameter of 1.6 mm, and a thickness of 0.3 mm was used. 6a and 6 b is a central conductor, by etching the copper foil of 35μm thickness, in the present example is formed so as to be perpendicular while insulating microwave magnetic material 5 top bent mechanically. Reference numeral 7 denotes a ceramic laminate, in which an electrode is formed on a dielectric layer, and this is laminated to incorporate a capacitor for impedance matching. Reference numeral 8 denotes a dummy resistance element for using this embodiment as an isolator. Reference numeral 9 denotes a permanent magnet for applying a DC magnetic field. An upper metal case 10 also serves as a magnetic yoke.

The center conductor 6a is bent along the side surface from the upper surface of the microwave magnetic body 5, one end of the center conductor 6a is connected to the connection line 3a, and the other end is connected to the connection line 3b. The center conductor 6b is also bent along the side surface from the upper surface of the microwave magnetic body 5, and one end of the center conductor 6b is connected to the connection line 3b. The other end of the center conductor 6b is connected to the ground electrode 12 which is a connection pad provided on the upper surface of the ceramic laminate. The ground electrode 12 is further connected to the electrode 3d on the insulating sheet through a through hole in the ceramic laminate and is grounded.
FIG. 3 shows a perspective view of the structure in which the members are arranged and assembled as described above. The permanent magnet and the metal case (upper) are omitted so that the internal structure can be confirmed. Thus, since the ceramic laminate 7 is arranged side by side on the microwave magnetic body 5, the other end of the center conductor 6 b extends to the ground electrode 12 having substantially the same height, and can be easily connected. It has a structure.

  Table 1 shows the high frequency characteristics of the non-reciprocal circuit device configured as described above.

  Next, FIG. 4 shows a perspective view of a second embodiment of the two-port nonreciprocal circuit device according to the present invention. In the first embodiment, it is considered that the impedance may not be matched because the current deviates from the ideal state due to the stray capacitance of the connection lines 3a and 3b. The inventors estimated and studied that the effect of the stray capacitance can be canceled by setting the crossing angle of the center electrodes to be larger than 90 degrees. The result is shown in FIG. 5 as a change in insertion loss when the crossing angle is changed. From the figure, in order to make the insertion loss 0.4 dB or less, the crossing angle needs to be 95 degrees or more and 113 degrees or less. In the present embodiment of FIG. 4, the angle at which the first central conductor 6a and the second central conductor 6b intersect is 105 degrees.

  Table 2 shows the reflection and insertion loss according to this example. From this, it can be confirmed that the peak frequency of the insertion loss and the peak frequency of the reflection loss coincide, and the insertion loss is effective.

  The lumped constant type isolator of the present invention can be used for high-frequency wireless communication devices such as mobile phones and mobile terminals.

It is a disassembled perspective view of one Example which shows the 2 port type nonreciprocal circuit device by this invention. It is the figure which showed the lower surface of the insulating sheet used for one Example of the 2 port type nonreciprocal circuit device by this invention. It is a perspective view after the assembly of one Example of the 2 port type nonreciprocal circuit device by this invention. It is the figure which showed the microwave magnetic body and center conductor part by 2nd Example by this invention. In the two-port nonreciprocal circuit device according to the present invention, it is a diagram showing the influence of the crossing angle between the central conductors on the insertion loss. It is a circuit diagram of a 2 port type nonreciprocal circuit device. It is the figure which showed the microwave magnetic body and center conductor part of the conventional 2 port type nonreciprocal circuit device.

Explanation of symbols

1: Metal case (bottom)
2: Insulation sheet
3a, 3b, 3c, 3d: Copper-plated electrode
4a, 4b, 4c: Through hole 5: Microwave magnet
6a, 6b: Center conductor 7: Ceramic laminate 8: Resistance element 9: Permanent magnet 10: Metal case (top)
11a, 11b: Connection terminal with external circuit 12: Ground electrode

Claims (7)

Two central conductors, a microwave magnetic body, a permanent magnet, an insulating sheet, and a ceramic laminate containing a plurality of matching capacitors are provided, and the central conductor intersects the upper surface of the microwave magnetic body. A two-port non-reciprocal circuit device, wherein at least a part of an ungrounded electrode provided and connected to one end of the central conductor is disposed below the microwave magnetic body,
The two-port nonreciprocal circuit device, wherein the ceramic laminate is disposed on a side of the microwave magnetic body on the insulating sheet. The two-port nonreciprocal circuit device according to claim 1, wherein the insulating sheet has flexibility. 3. The two-port nonreciprocal circuit device according to claim 1, wherein a connection line is formed on a surface of the insulating sheet, and electrical connection between the ceramic laminate and the central conductor is secured by the line. A two-port non-reciprocal circuit device characterized by comprising: The two-port nonreciprocal circuit device according to any one of claims 1 to 3, wherein the insulating sheet has through holes that electrically connect both surfaces thereof. . 5. The two-port nonreciprocal circuit device according to claim 1, wherein the two-port nonreciprocal circuit device includes a metal case, and the lower surface of the insulating sheet is electrically connected to the metal case. A two-port nonreciprocal circuit device characterized in that a stabilized line is formed. 6. The two-port nonreciprocal circuit device according to claim 1, wherein an intersection angle between the first center conductor and the second center conductor is 95 degrees or more and 113 degrees or less. A two-port nonreciprocal circuit device. The two-port nonreciprocal circuit device according to any one of claims 1 to 6, wherein a grounding connection pad is provided on the upper surface of the ceramic laminate, and one end of the central conductor is for the connection. A two-port nonreciprocal circuit device characterized by being connected to a pad.