JP2002084104A - Communicating device, non-reversible circuit element and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a non-reversible circuit element that prevents deterioration in characteristics due to the deviation of the center frequency of a pas band to a low-frequency side caused by the decrease in the strength of a magnetic pole due to the heat history of a permanent magnet, and at the same time, is composed of minimum number of required parts. SOLUTION: In a resin case 1 having a leading terminal 9, a center conductor 5 electrically continuous to the leading terminal 9, a ferrite core 4 that approaches the center conductor 5, a resistor 8 that is connected to the center conductor 5, and a capacitor 7, are provided. In a metal case comprising upper and lower yokes 2 and 3, the permanent magnet 6 for applying a static magnetic field to the ferrite core 4 is arranged. In the permanent magnet 6, the strength of the magnetic pole is set, so that the center frequency is shifted toward the high-frequency side by a specific quantity in advance prior to heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-reciprocal circuit device such as an isolator and a circulator used in a microwave band and the like, a communication device including the same, and a method of manufacturing the non-reciprocal circuit device.

[0002]

2. Description of the Related Art As a nonreciprocal circuit element used mainly in a microwave band, a center conductor electrically connected to the input / output terminal is provided in a resin case having an input / output terminal and a ground terminal. Conventionally, a ferrite core close to the ferrite core and a matching element connected to the center conductor are arranged, and a permanent magnet that applies a static magnetic field to the ferrite core is arranged in a metal case including an upper yoke and a lower yoke. Used.

[0003]

However, such a conventional non-reciprocal circuit device has the following problems to be solved.

When manufacturing a non-reciprocal circuit device and when mounting the non-reciprocal circuit device on a circuit board, solder bonding may be used. In order to perform this solder joining, a step of melting the solder at a high temperature is essential. Therefore, heat is inevitably applied to each component of the non-reciprocal circuit device. However, the permanent magnet used in the non-reciprocal circuit element is heated, and thus, undergoes irreversible demagnetization (hereinafter, referred to as “thermal demagnetization”), and its characteristics are deteriorated.

Here, regarding the conventional non-reciprocal circuit device,
This will be described with reference to FIG.

FIG. 5 shows a conventional non-reciprocal circuit device.
FIGS. 5A and 5B are diagrams showing a change in characteristics due to a difference in the presence or absence of heating, wherein FIG. 5A is a reflection loss, FIG. 5B is an insertion loss, and FIG.

Table 1 shows two conventional non-reciprocal circuit devices.
The change of the characteristic value in GHz before and after heating is shown.

[0008]

[Table 1]

In the nonreciprocal circuit device, the strength of the magnetic pole of the permanent magnet decreases due to thermal demagnetization. As shown in FIG. 5, the center frequency of the reflection loss, insertion loss, and isolation characteristics is reduced before heating. Shifts to the low frequency side from the state. Further, as shown in Table 1, the characteristics of reflection loss, insertion loss, and isolation deteriorate.

[0010] To solve such a problem, Japanese Patent Application Laid-Open No. 8-213808 is disclosed.

In this non-reciprocal circuit device, a center conductor, a ferrite core, a capacitor substrate provided with a matching element, and a permanent magnet are arranged between an upper yoke and a lower yoke also serving as a case, and the permanent magnet is formed of SmCo · 2. Formed with a -17 series magnet,
The structure is such that the magnet is covered with a heat insulating material to prevent the central frequency from being shifted to the low frequency side due to the thermal demagnetization of the permanent magnet, thereby preventing the characteristics from deteriorating.

However, by using a heat insulating material,
The thickness of the non-reciprocal circuit element becomes thicker by the thickness of the heat insulating material, which is a problem when downsizing (reducing the height). In addition, the use of the heat insulating material increases the components of the non-reciprocal circuit device,
The price of the non-reciprocal circuit device increases. Sm for permanent magnet
When a rare earth magnet such as Co.2-17 is used, since the permanent magnet itself is a conductor, an eddy current is generated on the surface when the magnet is arranged at a position near the center conductor and coupled to a high-frequency electromagnetic field, A new problem arises in that the characteristics of the non-reciprocal circuit device deteriorate.

An object of the present invention is to prevent a phenomenon in which the center frequency of a pass band is shifted to a lower frequency side, which is caused by thermal demagnetization of a permanent magnet, and the characteristic is degraded, and is constituted by minimum necessary parts. And a communication device provided with the same.

[0014]

SUMMARY OF THE INVENTION The present invention provides a center conductor,
A ferrite core, and a permanent magnet that applies a static magnetic field to the ferrite core, so that the frequency at which the reflection loss is minimized before heating is shifted by a predetermined amount to a higher frequency side than the frequency at which the reflection loss is minimized after heating. Alternatively, the strength of the magnetic pole is set so that the frequency at which the isolation becomes maximum before heating is shifted by a predetermined amount to a frequency higher than the frequency at which the isolation becomes maximum after heating. Accordingly, the predetermined amount of frequency shift occurs due to heating when the irreversible circuit element is mounted on a circuit board of a communication device or the like in a manufacturing process of the communication device, and a desired irreversible circuit characteristic appears. I do.

Further, according to the present invention, the permanent magnet is constituted by a ferrite magnet.

The present invention also provides a difference between a frequency at which reflection loss is minimized before heating and a frequency at which reflection loss is minimized after heating, or a frequency at which isolation is maximized before heating and an isolation is maximized after heating. The intensity of the magnetic pole is set so that the difference from the frequency becomes within the range of more than 0% and less than 2% of the center frequency of the pass band.

Further, the present invention manufactures a non-reciprocal circuit device including a step of heating at least the permanent magnet after determining the strength of the magnetic pole of the permanent magnet. in this way,
By performing thermal demagnetization in advance in the manufacturing process of the non-reciprocal circuit,
Even if the non-reciprocal circuit element is heated when the communication device is mounted on the circuit board in the manufacturing process of the communication device, or if the non-reciprocal circuit element generates heat when the communication device is actually used, the heat is reduced. There is no change in the characteristics of the nonreciprocal circuit device due to magnetism.

Further, according to the present invention, a non-reciprocal circuit device is manufactured by setting the heating temperature in the heating step to 85 ° C. or higher.

Further, according to the present invention, a communication device is provided with the non-reciprocal circuit device.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An isolator according to a first embodiment will be described with reference to FIGS.

FIG. 1 is an exploded perspective view of the isolator. As shown in FIG. 1, in a resin case 1 having a lead terminal 9, a center conductor 5 electrically connected to the lead terminal 9, a ferrite core 4 close to the center conductor 5, and a termination connected to the center conductor 5. The upper yoke 2 and the lower yoke 3 are provided with a resistor 8 as a resistor and a capacitor 7 as a matching element.
A permanent magnet 6 for applying a static magnetic field to the ferrite core 4 is disposed in a metal case composed of the following. The permanent magnet 6
The strength of the magnetic pole is set in advance so that the center frequency is shifted to the high frequency side by a predetermined amount.

FIG. 2 shows the change in characteristics before and after heating the isolator at 240 ° C. FIG. 2A shows reflection loss, FIG. 2B shows insertion loss, and FIG. 2C shows frequency characteristics of isolation. FIG.

Table 2 shows changes in characteristic values of the isolator at 2 GHz before and after heating.

[0024]

[Table 2]

Thus, by heating the isolator,
The optimum frequencies of the reflection loss, the insertion loss, and the isolation are shifted toward the lower frequency side by a predetermined amount. This is because the strength of the magnetic pole is reduced by a predetermined amount due to the thermal demagnetization of the permanent magnet. Therefore, as a result of the shift of the predetermined amount, the strength of the magnetic pole is adjusted so that the reflection loss, the insertion loss, and the isolation are optimized at the predetermined frequency before heating so that the optimum characteristics are obtained at the operating frequency. Determine.

By performing this setting, as shown in FIG. 2, the center frequency shifts by a predetermined amount to the lower frequency side due to the influence of heating due to mounting on a circuit board or the like, and the optimum frequency is used in the 2 GHz band which is the operating frequency. Reflection loss, insertion loss and isolation can be obtained.

In the case of an isolator, the terminating resistor generates heat and the permanent magnet is heated by the reflected power.
In anticipation of the thermal demagnetization due to this heating, if the frequency at which the reflection loss is minimized or the isolation is maximized is shifted by a predetermined amount toward the high frequency side, it is possible to prevent a change in frequency characteristics due to the heat generated by the terminating resistor. .

Further, even when the shift of the center frequency due to heating during mounting or use does not reach a predetermined amount, the effect of thermal demagnetization can be reduced.

Further, by using the ferrite magnet as the permanent magnet 6, there is no deterioration of the characteristic value due to the eddy current loss due to the use of the rare earth magnet.

As shown in FIG. 2 and Table 2, when a ferrite magnet is used, the frequency shift is about 1% of the center frequency of the pass band. Therefore, if the amount of deviation of the center frequency before and after heating is set to 2% or more, even if thermal demagnetization occurs, a deviation of 1% or more will occur, and the characteristics will be degraded.

Therefore, when the deviation of the center frequency before and after heating is set to about 1% using a ferrite magnet as the permanent magnet,
The deviation amount of the center frequency before and after heating is set to be larger than 0% and within 2%.

In an ideal non-reciprocal circuit device, the amount of change in frequency between reflection loss and isolation before and after heating is the same, but the amount of change in reflection loss is usually larger than that in isolation. large. Therefore, the shift amount of the center frequency is set depending on which of the reflection loss and the isolation is prioritized. For example, if the reflection loss has a stricter standard with respect to the actual characteristics, the deviation amount is set so that the reflection loss is minimized by thermal demagnetization.

Next, a method of manufacturing the isolator according to the second embodiment will be described with reference to FIG.

FIG. 3 shows a flow chart of the manufacturing process of the isolator.

As shown in FIG. 3, in the manufacturing process of the isolator, after assembling the components, the strength of the magnetic pole is adjusted in consideration of the shift of the center frequency to the lower frequency side due to heating, and thereafter, This is a series of flows in which the isolator is heated (killed) and a characteristic test is performed.

Once the isolator is heated up to a predetermined temperature and is thermally demagnetized to change its characteristics, the thermal demagnetization does not occur again even if the temperature is raised again to the above temperature. Does not change.

Accordingly, by providing the manufacturing process with a step of heating to a temperature applied when the isolator is mounted on the circuit board, or to a temperature applied to the magnet after actually being used, the mounting of the isolator or Prevents changes in properties due to heat during use.

Specifically, when the isolator is to be mounted on a circuit board by soldering, about 240
Heat to ° C.

In the case of mounting by screwing or the like instead of soldering, a change in characteristics due to heating is prevented by raising the temperature to the upper limit of the environmental temperature in which the isolator is used. That is, in a mobile communication device in which the isolator is often used, the upper-limit temperature of use is 8
Since it is 5 ° C., it is heated at 85 ° C. or more. Further, the heating is performed at a temperature equal to or higher than the heat generation temperature of the terminating resistor due to the reflected power.

Next, the configuration of the communication device according to the third embodiment will be described with reference to FIG. In FIG. 4, ANT is a transmitting / receiving antenna, DPX is a duplexer, BPFa, BP
Fb is a band pass filter, AMPa, AMPb, respectively.
Is an amplifier circuit, MIXa and MIXb are mixers, OSC is an oscillator, SYN is a frequency synthesizer, and ISO is an isolator.

MIXa represents the input IF signal and SYN
, The BPFa passes only the transmission frequency band of the mixed output signal from the MIXa, the AMPa amplifies the power, and the isolator ISO
And ANT via DPX. The isolator ISO blocks a reflected signal from DPX or the like to AMPa, thereby preventing generation of distortion in AMPa. AMPb is D
The received signal extracted from the PX is amplified. BPFb is A
Only the reception frequency band of the reception signal output from MPb is passed. MIXb mixes the frequency signal output from the SYN with the received signal to produce an intermediate frequency signal I.
Output F.

The isolator ISO shown in FIG.
An isolator having the above-described structure and a manufacturing method is used. As described above, by using an isolator that has a small insertion loss, a small size, a low profile, and a light weight, a communication device such as a mobile phone or the like that has high power efficiency as a whole and is thin and lightweight can be obtained.

[0043]

According to the present invention, the frequency at which the reflection loss is minimized before heating is shifted to a higher frequency side by a predetermined amount than the frequency at which the reflection loss is minimized after heating, or the frequency is minimized before heating. By setting the strength of the magnetic poles of the permanent magnet so that the frequency at which the maximum of the isolation is shifted by a predetermined amount to a higher frequency side than the frequency at which the isolation becomes the highest after the heating, the low frequency of the center frequency due to the heating is set. The shift to the side can be corrected, and predetermined electrical characteristics can be imparted by heating during mounting by soldering to a circuit board or heating during use. Further, even if a predetermined amount of shift of the center frequency does not occur due to the thermal demagnetization, deterioration of the characteristics due to the thermal demagnetization can be reduced.

Further, according to the present invention, a component such as a heat insulating material for preventing the influence of thermal demagnetization is not required, and a non-reciprocal circuit device can be formed at a small size and at low cost.

Further, according to the present invention, by using a ferrite magnet as the permanent magnet, it is possible to prevent deterioration of characteristics due to eddy current loss on the magnet surface.

Further, according to the present invention, a change in characteristics due to heating during mounting can be prevented by performing thermal demagnetization in advance in a heating step when manufacturing a non-reciprocal circuit device.

According to the present invention, even in the case where the solder joint is not used, a change in characteristics due to heating can be prevented by adding a step of heating at a use upper limit temperature of a device equipped with a non-reciprocal circuit device. be able to.

Further, according to the present invention, when the non-reciprocal circuit element is an isolator, it is possible to prevent a change in characteristics due to heat generation of the terminating resistor due to reflected power.

Further, according to the present invention, the communication device including the non-reciprocal circuit element can prevent the characteristics from changing due to heat generation and heating in the use environment, and maintain excellent communication characteristics.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a change in characteristics before and after heating the non-reciprocal circuit device at 240 ° C.

FIG. 3 is a flowchart of a manufacturing process of the non-reciprocal circuit device.

FIG. 4 is a block diagram of a communication device according to a third embodiment;

FIG. 5 is a diagram showing a change in characteristics before and after heating a conventional non-reciprocal circuit device at 240 ° C.

[Explanation of symbols]

 1-resin case 2-upper yoke 3-lower yoke 4-ferrite core 5-center conductor 6-permanent magnet 7-capacitor 8-resistor 9-lead terminal

Claims (7)

[Claims] 1. A non-reciprocal circuit device comprising a center conductor, a ferrite core adjacent to the center conductor, and a permanent magnet for applying a static magnetic field to the ferrite core, wherein a strength of a magnetic pole of the permanent magnet is determined. The frequency at which the reflection loss is minimized before heating is shifted by a predetermined amount from the frequency at which the reflection loss is minimized after heating, or the frequency at which the isolation becomes maximum before heating is changed to the maximum isolation after heating. A non-reciprocal circuit element which is shifted in advance by a predetermined amount from the frequency to be obtained. 2. The non-reciprocal circuit device according to claim 1, wherein the permanent magnet is a ferrite magnet. 3. The nonreciprocal circuit device according to claim 2, wherein the predetermined amount is in a range of more than 0% and less than 2% of a center frequency of a pass band. 4. A method for manufacturing a non-reciprocal circuit device, comprising: a center conductor, a ferrite core adjacent to the center conductor, and a permanent magnet for applying a static magnetic field to the ferrite core, wherein a magnetic pole of the permanent magnet is provided. A method for manufacturing a non-reciprocal circuit device, comprising a step of heating at least the permanent magnet after determining the strength. 5. A heating temperature in the heating step is 85.
The method for producing a non-reciprocal circuit device according to claim 4, wherein the temperature is not less than ° C. 6. A non-reciprocal circuit device manufactured by the method according to claim 4. Description: 7. A communication device comprising the non-reciprocal circuit device according to claim 1.