JP2003017906A - Irreversible circuit device and communication unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized irreversible circuit device in which the external electrode provided on the printed circuit board can surely be connected to a measurement electrode and a mount side electrode and to provide a communication unit. SOLUTION: The irreversible circuit device 1 mainly comprises a metal-made case 5, an internal electric component contained in the metal-made case 5 and the printed circuit board 40 or the like. The internal electric component comprises a permanent magnet, a ferrite to which the permanent magnet applies a direct-current magnetic field, a center electrode assembly comprising a plurality of center electrodes arranged in the ferrite, a matching capacitor element and a resistive element or the like. The thickness of an earthing purpose external electrode 55 or the like formed to a lower side 40b of the printed circuit board 40 is selected to be 0.02 mm or more and 0.1 mm or below.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-reciprocal circuit device and a communication device.

[0002]

2. Description of the Related Art Generally, in a mobile communication device such as a mobile phone, there is a strong demand for price and high quality in view of its application, and accordingly, in a lumped constant type isolator (non-reciprocal circuit device). Also, low price and high quality are required.

As such a lumped-constant type isolator, there is known one formed by mounting an internal electrical component housed in a metal case on a circuit board. External electrodes are formed on the bottom surface of the circuit board, and are connected to, for example, mounting-side electrodes of a mounting board for a communication device. Since the external electrodes have almost no thickness, the bottom surface of the circuit board is substantially flat.

The internal electrical parts of this isolator include a permanent magnet, a center electrode assembly including a ferrite to which a DC magnetic field is applied by the permanent magnet, and a plurality of center electrodes arranged on the ferrite. These internal electrical components are soldered to the electrical circuit pattern on the circuit board. The metal case not only functions as a case for the isolator, but also as a magnetic yoke.

[0005]

However, the circuit board may be warped by the heat applied when soldering the internal electric components to the circuit board. Even when such an isolator is placed on the inspection device, the external electrode of the isolator may float from the measurement electrode of the inspection device due to the warp of the circuit board generated during soldering. That is, there is a problem that the electrical measurement of the isolator cannot be performed accurately.

Further, a resist pattern is formed around the mounting side electrode of the mounting substrate on which the isolator is mounted. This resist pattern has the effect of preventing solder flow and the effect of improving the positioning accuracy of the isolator by the self-alignment effect. However, when the isolator is placed on the resist pattern of the mounting substrate, the external electrode of the isolator may float above the mounting side electrode of the mounting substrate due to the film thickness of the resist pattern. In this case, a solder joint defect between the external electrode of the isolator and the electrode of the mounting substrate is likely to occur.

In order to solve the above-mentioned problems, it is conceivable to increase the thickness of the external electrode of the isolator so as to suppress the influence of the warp of the circuit board or to make the structure cross the resist pattern. There is a new problem that the mounting height of the isolator becomes large only by increasing the thickness of the isolator.

Therefore, an object of the present invention is to provide a small non-reciprocal circuit device and a communication device in which the external electrodes provided on the circuit board can be reliably connected to the measuring electrodes and the mounting side electrodes.

[0009]

To achieve the above object, the nonreciprocal circuit device according to the present invention comprises (a) a permanent magnet and (b) a ferrite to which a direct current magnetic field is applied by the permanent magnet. A center electrode assembly composed of a plurality of center electrodes arranged on the ferrite; and (c) a metal case for housing the permanent magnet and the center electrode assembly.
(D) a circuit board for mounting the center electrode assembly, which is combined with the metal case, and (e) mounts the center electrode assembly on a first main surface of the circuit board, On the surface of the second main surface facing the first main surface, 0.
An external electrode having a thickness of 02 mm or more and 0.1 mm or less is provided.

With the above structure, the thickness of the external electrode formed on the second main surface of the circuit board is 0.02 mm or more and 0.1 m or more.
Since it is less than or equal to m, 0.02 m is provided between the mounting substrate on which the non-reciprocal circuit device is mounted and the circuit board of the non-reciprocal circuit device.
A gap of m or more and 0.1 mm or less is formed. Therefore, if
Even if the circuit board of the non-reciprocal circuit element is warped by the solder heat, the external electrodes of the isolator will not float above the mounting side electrodes of the mounting board.

Further, it is preferable that the external electrode has a divided through hole provided on the side surface of the circuit board. Here, the divided through hole means a through hole having a shape obtained by dividing the through hole in its axial direction. For example, this includes a through hole having a semicircular cross section formed by dividing a through hole having a circular cross section into two in the axial direction. As a result, when the nonreciprocal circuit device is solder-mounted on the mounting substrate, solder fillets are formed in the divided through holes, and the solder joint strength is improved.

Since the communication device according to the present invention includes the non-reciprocal circuit device having the above-mentioned characteristics, it can have excellent electric characteristics.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION 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. In each embodiment, the same parts and the same parts are designated by the same reference numerals, and duplicated description will be omitted.

[First Embodiment, FIGS. 1 to 6] FIG. 1 is an exploded perspective view of an embodiment of a nonreciprocal circuit device according to the present invention. As shown in FIG. 1, the isolator 1 is roughly composed of a metal case 5, an internal electric component 8, a circuit board 40 and the like. The internal electric component 8 is roughly composed of two permanent magnets 9, a center electrode assembly 13, and matching capacitor elements C1 to C1.
It is composed of C4, a resistance element R, and a ground plate 30.

The metal case 5 has an upper wall 5a and four side walls 5b. The metal case 5 is formed by punching and bending a metal plate.

The two permanent magnets 9 each have a substantially rectangular shape and are arranged so that a DC magnetic field is formed from one permanent magnet 9 to the other permanent magnet 9.

The circuit board 40 is a substantially rectangular board.
Three divided through-holes 46 are formed on each of the side surfaces 40c in the long side direction of the circuit board 40.
One divided through hole 46 is formed in c. The divided through hole 46 is formed, for example, as follows. When manufacturing the circuit board 40, the circuit board 40
After forming a through hole having a circular cross section on the outer shape cutting line, the circular through hole is divided into two in the axial direction at the same time as the outer cutting of the circuit board 40 to form a divided through hole 46 having a semicircular cross section. To do.

An input electrode pattern 43, an output electrode pattern 44 and a ground electrode pattern 45 are formed on the upper surface 40a of the circuit board 40. These electrode patterns 43 to 45 are electrically connected to the external electrodes 53 to 55 provided on the edge portion of the circuit board 40. That is, the input electrode pattern 43 is electrically connected to the input external electrode 53, the output electrode pattern 44 is electrically connected to the output external electrode 54, and the ground electrode pattern 45 is connected to the ground external electrode 55. It is electrically connected. Each of the external electrodes 53 to 55 has a divided through hole 46, and extends through the divided through hole 46 to the lower surface 40b of the circuit board 40 as shown in FIG.

The external electrodes 53 to 55 are set to be slightly wider than the width of the divided through hole 46. When the isolator 1 is mounted on the mounting substrate, a solder fillet is formed in the divided through hole 46, and the solder joint strength can be improved.

The external electrodes 53 to 55 are coated with silver. As a result, the solder wettability between the external electrodes 53 to 55 and the mounting-side electrodes of the mounting substrate is improved, soldering defects can be reduced, and the solder joint strength can be improved. In addition to silver, it may be coated with gold, tin or solder.

The external electrode 5 formed on the lower surface 40b
The thickness Z2 of 3 to 55 (see FIG. 4) is, for the reason described later,
It is set to 0.02 mm or more and 0.1 mm or less. Book first
In the embodiment, the thickness of each of the external electrodes 53 to 55 is set to about 0.1 mm.

As shown in FIG. 1, the matching capacitor elements C1 to C4 have connecting capacitor electrodes on the upper and lower surfaces.

The resistance element R has a rectangular parallelepiped shape, and has connection electrodes on its left and right sides. This resistance element R is
The thickness is set to be substantially the same as that of the matching capacitor elements C1 to C4.

The ground plate 30 has a rectangular parallelepiped shape. The ground plate 30 is made of a copper plate or the like and has electrical conductivity. This ground plate 30 is used for the matching capacitor element C1.
The thickness is set to be approximately the same as C4.

The center electrode assembly 13 intersects the substantially rectangular microwave ferrite 20 and two conducting wires (for example, copper wire and silver wire) coated with an insulator so that the intersecting angle becomes approximately 90 degrees. The center electrodes 21 and 22 are formed by winding the ferrite 20 around the surface of the ferrite 20.

The above components are assembled as follows. On the circuit board 40, the matching capacitor elements C1 to C4, the ground plate 30 and the resistance element R are placed,
It is mounted by a method such as soldering. At this time, the connecting capacitor electrodes on the lower surfaces of the matching capacitor elements C1 and C2 are input to the ground electrode pattern 45 formed on the upper surface 40a of the circuit board 40, and the connecting capacitor electrodes on the lower surface of the matching capacitor element C3 are input. Electrode pattern 43
Further, the connecting capacitor electrodes on the lower surface of the matching capacitor element C4 are electrically connected to the output electrode patterns 44 by a method such as soldering.

The resistance element R is placed on the non-electrode pattern portion 49 of the circuit board 40. That is, the ground electrode pattern 45 and the resistance element R are in an electrically non-contact state.

Next, the center electrode assembly 13 is placed on the matching capacitor elements C1 to C4, the resistance element R, and the ground plate 30 and mounted by a method such as soldering. At this time, one end of the center electrode 21 has a matching capacitor element C1,
It is electrically connected to the connection capacitor electrode on the upper surface of C3 and one connection electrode of the resistance element R. One end of the center electrode 22 is electrically connected to the connection capacitor electrodes on the upper surfaces of the matching capacitor elements C2 and C4 and the connection electrode at the other end of the resistance element R. The other ends of the center electrodes 21 and 22 are electrically connected to the ground plate 30. As a result, the center electrode assembly 13 is fixed to the elements C1 to C4, R and the ground plate 30.

Next, the two permanent magnets 9 are placed. The center electrode assembly 13 is disposed between the two permanent magnets 9, and a DC magnetic field is applied by the two permanent magnets 9. Since the elements C1 to C4 and R and the ground plate 30 have substantially the same thickness, the upper surfaces of the elements C1 to C4 and R and the ground plate 30 are substantially parallel to the circuit board 40. Make up. Therefore, the ferrite 20 of the center electrode assembly 13 mounted on the same surface can be arranged substantially perpendicular to the circuit board 40.

Further, the metal case 5 is covered and bonded to the ground electrode pattern 45 of the circuit board 40 or the ground external electrode 55 by soldering. Thus, as shown in FIGS. 3 and 4, length 3.2 × width 2.5 × height 2.0 m
m isolators 1 are formed. FIG. 5 is an electrical equivalent circuit diagram of the isolator 1 shown in FIGS. 3 and 4.

By the way, in FIG. 4, the thickness of the external electrodes 53 to 55 formed on the lower surface 40b of the circuit board 40 (in other words, from the surface of the external electrodes 53 to 55 to the circuit board 4).
If only the thickness Z2 of the step to the lower surface 40b of 0) is thickened, the mounting height h of the isolator 1 becomes high and the isolator 1 becomes large. Therefore, the external electrodes 53-5
It is considered that the thickness of the body of the isolator 1 (in other words, the dimension from the lower surface 40b of the circuit board 40 to the upper wall 5a of the metal case 5) Z1 is reduced by an amount corresponding to the increased thickness of 5.

Therefore, the height h of the isolator 1 is set to 2.0.
With the thickness maintained at mm, various thicknesses Z2 of the external electrodes 53 to 55 and the thickness Z1 of the main body of the isolator 1 were manufactured and the insertion loss was examined. In addition, each of the isolators 1 was designated as the test body Nos. 1 to 4. The results are shown in Table 1.

The thickness Z2 of the external electrode of test body No. 1
= 0 mm means that the external electrodes 53 to 55 are embedded in the circuit board 40 and the apparent thickness Z2 of the external electrodes is set to 0 mm.

[0034]

[Table 1]

For the reasons described in Table 1 and later, the test sample No.
It can be seen that it is preferable to set the thickness Z2 of the external electrodes 53 to 55 to 0.02 mm or more and 0.10 mm or less as in the isolator 1 of No. 2. Hereinafter, the reason will be described from the viewpoint of electrical characteristics and mounting conditions.

First, the electrical characteristics of the isolator 1, that is, the insertion loss will be described. In Table 1, the thickness Z2 of the external electrodes 53 to 55 of the test bodies No. 1 and 2 is 0 mm to
In the isolator 1 having a length of 0.10 mm, an increase in insertion loss was not recognized, and the insertion loss was smaller than the test bodies Nos. 3 and 4 (the insertion loss was constant at 2.11 dB).

On the other hand, the external electrodes 53-
The isolator 1 having the thickness Z2 of 55 of 0.15 mm to 0.2 mm has an increased insertion loss (2.13 dB to 2.15 d).
B) was recognized. While keeping the height h of the isolator 1 constant, the external electrodes 53- formed on the lower surface 40b.
When the thickness Z2 of 55 is increased, the thickness Z1 of the main body of the isolator 1 is decreased, and the circuit board 40 approaches the upper wall 5a side. That is, the ferrite 20 is the upper wall 5 of the metal case 5.
Approach a. It is considered that, as a result, the electromagnetic field coupling between the center electrodes 21 and 22 via the ferrite 20 weakened, and the insertion loss of the isolator 1 increased. From the above results, regarding the electrical characteristics, the external electrodes 53 to 5
It can be seen that the isolator 1 having the thickness Z2 of 5 of 0.1 mm or less is good.

Next, the mounting conditions for surely mounting the isolator 1 on the mounting substrate will be described. The thickness of the resist pattern formed on the mounting substrate is 0.01
It is about mm to 0.02 mm. Considering the thickness of this resist pattern, the thickness Z2 of the external electrodes 53 to 55 is 0.
01 mm or more is required. Further, the circuit board 40 mounts the matching capacitor elements C1 to C4 and the resistance element R,
It slightly warps due to the solder heat generated when soldering. Therefore, in order to ensure the reliability of the solder bonding between the mounting substrate and the external electrodes 53 to 55, the thickness Z2 of the external electrodes 53 to 55 is set.
Needs to be set to 0.02 mm or more.

Therefore, for the above reason, the isolator 1
Shows that it is preferable to set the thickness Z2 of the external electrodes 53 to 55 in the range of 0.02 mm or more and 0.1 mm or less. As a result, the external electrodes 53 to 55 of the isolator 1 are
Is solved from the measurement electrode of the inspection device, the external electrodes 53 to 55 provided on the circuit board 40 can be reliably connected to the mounting board, and the size is small and the insertion loss is small. The isolator 1 can be obtained.

[Second Embodiment, FIG. 6] As shown in FIG. 6, in the isolator 2 of the second embodiment, a circuit board 50 is formed by using a ceramic multilayer board.

A ground electrode pattern 45 and connection electrode patterns 51 and 52 are formed on the upper surface 50a of the circuit board 50. An input external electrode 53, an output external electrode 54, and a ground external electrode 55, each having a divided through hole 46, are provided on the edge of the circuit board 50. The circuit board 50 is internally provided with a matching capacitor element C1.
To C4 and a resistance element R are formed, and they are electrically connected to each other through the via holes and the internal circuit pattern provided in the circuit board 50 together with the electrode patterns 45, 51 and 52. Connection electrode patterns 51, 52
Are connected to one ends of the center electrodes 21 and 22, and the ground electrode pattern 45 is connected to the other ends of the center electrodes 21 and 22.

The isolator 2 has the same effects as the isolator 1 shown in the first embodiment. Further, the matching capacitor element C1 is provided inside the circuit board 50.
Since C4 to C4 and the resistance element R are formed, the number of solder joints can be reduced and the production cost of the isolator 2 can be reduced as compared with the isolator 1.

[Third Embodiment, FIG. 7] In the third embodiment,
A mobile phone will be described as an example of the communication device according to the present invention.

FIG. 7 is an electric circuit block diagram of the RF portion of the mobile phone 120. In FIG. 7, reference numeral 122 is an antenna element, 123 is a duplexer, 124 and 126 are transmission side power amplifiers, 125 is a transmission side interstage bandpass filter, 127 is a transmission side mixer, 128 is a reception side low noise amplifier, and 129 is reception. Bandpass filter for side stage, 130
Is a receiving side mixer, 131 is an isolator, 132 is a voltage controlled oscillator (VCO), and 133 is a local band pass filter.

Here, as the isolator 131, the isolators 1 and 2 of the first and second embodiments can be used. By mounting the isolators 1 and 2, it is possible to realize a low-cost and highly reliable mobile phone.

[Other Embodiments] The present invention is not limited to the above-described embodiments, but can be modified into various configurations within the scope of the gist of the present invention. For example, the center electrode is not limited to a conductor wire (having a substantially circular cross section), but may be a metal foil (having a flat cross section). The shape of the center electrode assembly is not limited to the rectangular shape,
The shape of the cylinder and the shape of the deformed corner are arbitrary. Further, the shape of the permanent magnet may be circular, triangular with rounded corners, or the like, instead of being rectangular.

In addition to the isolator, the present invention can be applied to various non-reciprocal circuit devices such as circulators.

[0048]

As is apparent from the above description, according to the present invention, the thickness of the external electrode formed on the second main surface of the circuit board is 0.02 mm or more and 0.1 mm or less. A gap of 0.02 mm or more and 0.1 mm or less is formed between the mounting board on which the circuit element is mounted and the circuit board of the nonreciprocal circuit element. Therefore, the external electrodes of the circuit board can be reliably brought into contact with the mounting-side electrodes of the mounting board. Further, since the non-reciprocal circuit device has a low loss, a measurement error is likely to cause a problem. However, according to the present invention, since the insertion loss is not deteriorated, the measurement with a small error can be performed.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a non-reciprocal circuit device according to the present invention.

FIG. 2 is a bottom view of the circuit board shown in FIG.

3 is an external view of the nonreciprocal circuit device shown in FIG. 1 after completion of assembly.

4 is a side view of the non-reciprocal circuit device shown in FIG.

5 is an electrical equivalent circuit diagram of the non-reciprocal circuit device shown in FIG.

FIG. 6 is an exploded perspective view showing a second embodiment of a non-reciprocal circuit device according to the present invention.

FIG. 7 is a block diagram showing an embodiment of a communication device according to the present invention.

[Explanation of symbols]

1, 2 ... Isolator (non-reciprocal circuit element) 5 ... Metal case 9 ... Permanent magnet 13 ... Center electrode assembly 20 ... Microwave ferrite 21, 22 ... Center electrode 30 ... Ground plate 40, 50 ... Circuit board 40b ... bottom surface 40c ... side surface 46 ... Dividing through hole 53-55 ... External electrodes 120 ... Mobile phone (communication device)

Claims (3)

[Claims] 1. A center electrode assembly comprising a permanent magnet, a ferrite to which a DC magnetic field is applied by the permanent magnet, and a plurality of center electrodes arranged on the ferrite, the permanent magnet and the center electrode assembly. And a circuit board for mounting the center electrode assembly, which is combined with the metal case, and the center electrode assembly is mounted on a first main surface of the circuit board. In addition, an external electrode having a thickness of 0.02 mm or more and 0.1 mm or less is provided on the surface of the second main surface facing the first main surface. 2. The nonreciprocal circuit device according to claim 1, wherein the external electrode has a divided through hole provided on a side surface of the circuit board. 3. A communication device comprising the non-reciprocal circuit device according to claim 1.