JP2000021639A - Inductor, resonance circuit using the same, matching circuit, antenna circuit, and oscillation circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inductor, a resonance circuit using a inductor, matching circuit, and an active antenna circuit which has various functions despite its small-size and light-weight. SOLUTION: A closed magnetic circuit 1-1 with high magnetic permeability is wound with coils 1-2, 1-3, 1-4, and 1-5, and when a DC bias current is supplied to the 1st coil 1-2, the inductance of the 2nd coil 1-3 varies with the bias current. The quantity of variation in the inductance of the 2nd coil 1-3 depends upon the quantity of the current supplied to the 1st coil 1-2 and the variation in magnetic permeability. Furthermore, the range of the inductance can properly be set by properly setting the numbers of turns, current, and the ring size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductor used in a high-frequency radio, a satellite broadcast receiver, a high-frequency circuit such as a wireless LAN, etc. About.

[0002]

2. Description of the Related Art Recent progress in portable devices has been remarkable, and in particular, there has been a remarkable reduction in size and thickness of the portable devices as well as higher performance and functions. Alternatively, with respect to the shape of the portable device, since the portable device is carried around by a person, protrusion of an antenna or the like is disliked.

In order to reduce the size of portable equipment, not only the size and thickness of electronic components used in the high-frequency circuit portion but also the number of components must be reduced to reduce the number of components. Functionalization is required.

[0004] In the high-frequency component industry, small-sized dielectric block antennas have recently appeared in order to solve this kind of problem. However, this type of antenna has a narrow sensitivity band and when used close to the ear,
Due to the influence of the human body, the impedance of the high-frequency circuit changes subtly and hinders communication.

[0005] Further, in a normal high-frequency circuit, although components are selected so as to meet the overall performance, the characteristics of these electronic components vary. In actuality, trimming or the like is performed on a specific mounted component to match the characteristics so that the performance as a product can be exhibited. At present, the ratio of the time cost required for this adjustment to the product cost is at a level that cannot be ignored. Further, in the environment where the portable device is used, communication may not be possible at worst in the worst case due to the accumulation of temperature characteristics of each element in the portable device.

[0006] Specifically, as a portable device, a cellular phone, a PDA, and the like can be given. 8 for mobile phones and PDAs
A frequency such as a 00 MHz band, a 1.5 GHz band, a 1.9 GHz band, or the like is given. Devices using such a frequency band are generally called high-frequency devices.

[0007] Mobile phones are small, lightweight and low-priced.
It shows explosive extension. Inside these devices, capacitors, resistors, and even coils are arranged,
A transmission filter of a specific frequency band, an impedance matching circuit, a resonance circuit, an oscillator circuit, and the like are provided. In order to satisfy the demands for further miniaturization and higher functionality while maintaining high reliability, a single device may exhibit two or more functions (P
HS / PDC composite, 800MHz analog winding, etc.)
There is a growing demand for lighter and shorter parts.

[0008]

As described above, with the development of portable devices, electronic components constituting the portable devices are also required to have higher functions, and inductors, one of the electronic components, are required. Is the same.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is an inductor capable of realizing various functions while being small and lightweight, a resonance circuit using the inductor, and a matching circuit. A circuit, an antenna circuit, and an oscillation circuit are provided.

[0010]

To solve the above-mentioned conventional problems, an inductor according to the present invention comprises a magnetic circuit made of a magnetic material, and a plurality of winding coils wound around the magnetic circuit.

In one embodiment, the magnetic circuit includes at least one of a thick film magnetic material, a thin film magnetic material, and a bulk material.
It is formed using one.

[0012] In one embodiment, there is provided a bias means for supplying a bias current to at least one of the winding coils.

The inductor according to the present invention includes a first element having an inductance component and a second element constituting a bias coil surrounding the magnetic layer, and an electromagnetic field generated when current is supplied to the bias coil of the second element. The field is arranged so as to reach the first element having an inductance component.

A resonance circuit according to the present invention is a resonance circuit in which an inductance component and a capacitance component are connected in parallel or in series. The inductor according to the present invention is applied as the inductance component, A bias current is applied to at least one of the coils.

In one embodiment, the resonance frequency is arbitrarily changed by using both the variation of the inductance component by the bias current and the variation of the capacitance component by applying a voltage to the capacitance component.

In one embodiment, a plurality of resonance frequencies are selectively set by changing the bias current.

The matching circuit of the present invention incorporates the inductor of the present invention in at least one of the impedances in order to match the input impedance and the output impedance.

The antenna circuit of the present invention is an array antenna in which a plurality of antenna elements are arranged, and the inductor of the present invention is incorporated in each input / output circuit for each of the antenna elements.

The oscillation circuit according to the present invention is an oscillation circuit including an inductance component and a capacitance component connected in parallel or in series, wherein the inductor according to the invention is applied as the inductance component, A bias current is applied to at least one of the winding coils.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the basic principle of the inductor of the present invention will be described.

When a conductor wire is wound around one side of a magnetic circuit made of a soft magnetic material or the like, and a current is applied to this, a magnetic field is generated according to Ampere's law. This magnetic field magnetizes the soft magnetic circuit in one direction.

H = N ・ I / 2πR (1) where N: number of windings of the conductor wire I: current of the conductor wire R: radius of the closed magnetic circuit Relationship between applied magnetic field H and magnetic susceptibility M Are linked by a magnetic permeability μ.

M = X _m μ ₀ H (2) μ = (1 + X _m ) μ ₀ (3) where X _m : magnetic susceptibility μ ₀ : vacuum permeability It suggests that the magnetic permeability of the soft magnetic material is changed by the current flowing through the coil wound around one side.

Since the magnetic permeability generally has nonlinearity, it can be considered as a function of the current (bias current) to be applied. If another conductor wire is wound around the closed magnetic circuit, the inductance of the coil can be handled as a function of the bias current.

Consider a case where two conductors are wound around a magnetic circuit as shown in FIG.

When a DC bias current I is applied to the coil 101-2, the magnetic permeability μ of the closed magnetic circuit made of a soft magnetic material changes,
Mutual inductance L ₂ of the coil 101-3 can be expressed as (4).

L ₂ = N ₁ N ₂ μ (I) S / 2πR (4) where R: radius of magnetic circuit S: cross-sectional area of magnetic circuit N ₁ , N ₂ : number of turns of coil I : Bias current flowing through coil 101-2 μ: Permeability What has been described here is that the inductance can be changed only by electrical adjustment using a magnetic ring (closed magnetic circuit) having a high permeability. Suggests.

By making good use of this effect,
The work which has been adjusted by mechanically cutting or shaving the coil spacing and the wiring pattern can be greatly improved.

In addition, it is possible to use even an element having a slight variation in characteristics without any particular difficulty.

That is, the inductor of the present invention includes a closed magnetic circuit made of a material having high magnetic permeability and a coil made of a conductor wire.
Alternatively, a form in which a bulk material or the like is mixed or formed using only a bulk material can be considered.In any case, a combination of a magnetic circuit and a coil is used. A multilayer lamination technique using dielectric ceramic green sheets or magnetic ceramic green sheets, including a printing method, is required.

(First Embodiment) FIG. 1 shows an inductor according to a first embodiment of the present invention. In FIG. 1, 1
-1 is a donut-shaped (ring-shaped) closed magnetic circuit having a cross-sectional area S and a radius R, which is made of a high-permeability magnetic material. 1-2 is a winding of N ₁ turns made of copper wire or the like to form a first coil. 1-3,1-
4,1-5, like the first coil 1-2, a winding of N ₁ turns of copper wire or the like. One closed magnetic circuit 1-
The number of coils wound around one is not limited to this embodiment.

The operating principle of the inductor 1 of the present embodiment is the same as the principle of the present invention described with reference to FIG. When a DC bias current _Ibias is applied to the first coil 1-2, the magnetomotive force induces the closed magnetic circuit 1-1 to generate a magnetic flux Φ directed in one axial direction. Since the magnetic flux Φ is generated according to the bias current _Ibias , the magnetic circuit 1-1 is in a state where a magnetic bias is applied to the entire magnetic circuit 1-1.

Due to the change in the magnetic flux Φ caused by the change in the bias current _Ibias , the magnetic circuit 1-1 having the cross-sectional area S becomes one of an unsaturated state, a saturated state, and an intermediate state between the unsaturated state and the saturated state. When viewed from the side of the second coil 1-3 that changes, the magnetic flux Φ of the magnetic circuit 1-1 has changed, and therefore, the inductance of the second coil 1-3 has changed.

In the inductor 1 of the present embodiment,
The following can be said.

1. The inductance of the second coil 1-3 is changed according to the amount of the bias current _Ibias supplied to the first coil 1-2.

2. First coil 1-2 and second coil 1-3
The product of the number of turns determines the capacity of the inductance.

3. The permeability μ generally depends on the applied magnetic field strength.

In other words, although the treatment depends on the magnetic field because of exhibiting the non-linear characteristic, the source of the magnetic field depends on the amount of the bias current _Ibias supplied to the first coil 1-2. This permeability μ can be regarded as a function of the current.

[0039] Accordingly, the inductance L ₂ of the second coil 1-3 is expressed by the following equation (5).

L ₂ = μ (I) N ₁ N ₂ S / 2πR (5) As described above, in the high-permeability closed magnetic circuit, a plurality of coils are wound and one of the first coils is wound. When a DC bias current flows through the second coil, the inductance of the other second coil changes according to the amount of the bias current. This second
The amount of change in the inductance of the coil depends on the amount of current flowing through the first coil and the amount of change in the magnetic permeability, and can be predicted based on the above equation (4). Further, the range of the inductance can be appropriately set by selecting the number of windings, the amount of current, and the ring size. In this embodiment,
Considering the amount of bias current and the number of windings, it is expected that there will be considerable latitude in the design.

(Second Embodiment) FIG. 2 shows an inductor according to a second embodiment of the present invention.

The inductor 2 of the second embodiment includes a closed magnetic circuit 2-1 made of a material having high magnetic permeability and one coil 2-
2 is provided. In the present embodiment, a bias current is supplied to the coil 2-2 to generate a magnetic flux.
It changes its own inductance. Therefore, FIG.
Although the bias current flows through the coil 2-2 itself, there is also an advantage that a simpler device structure can be obtained as compared with the embodiment shown in FIG.

FIG. 3 exemplifies a parallel resonance cycle of the coil 2-2 and the capacitor 2-3 of the inductor 2 shown in FIG. The resonant frequency of this parallel resonant circuit is
2 changes according to the change of the inductance L. As described above, when the magnitude of the bias current _Ibias of the coil 2-2 of the inductor 2 is changed, the inductance of the coil 2-2 changes. For this reason, the resonance frequency can be adjusted only by adjusting the bias current I _bias instead of the conventional adjustment of the coil interval or mechanical trimming.

FIG. 4 is a graph showing the relationship between the magnetic field and the magnetic flux density of a magnetic circuit made of a material having a high magnetic permeability.

If uniaxial anisotropy is given to the magnetic circuit,
Characteristics with extremely small hysteresis with respect to an applied magnetic field can be obtained. At this time, the applied magnetic field, which is generated by the bias current I _{bi the as,} a relation of the following equation (6).

H = NI _bias / 2πR (6) FIG. 5 is a graph showing the slope (differential system) of the tangent of the characteristic curve of the magnetic circuit shown in FIG. I have. As is clear from this graph,
It shows the maximum magnetic permeability near zero magnetic field, and decreases as the absolute value of the magnetic field increases.

(Third Embodiment) FIG. 6 shows a sectional structure of an inductor according to a third embodiment of the present invention. In the inductor 7 of the third embodiment, a first coil 7-2 and a second coil 7-
3 and a closed magnetic circuit 7-1 having high magnetic permeability is formed, and the first and second coils 7-2 and 7-3 surround the closed magnetic circuit 7-1.

The first and second coils 7-2 and 7-3 are made of a dielectric material 7-6 such as SiO ₂ having a thickness of 5 μm or more in order to prevent leakage of lines of magnetic force of the closed magnetic circuit 7-1.
Is trying to separate. Further, by the dielectric layer 7-5,
The first and second coils 7-2 and 7-3 are protected.

The structure of the inductor 7 according to the present embodiment can be realized by a ceramic green process or by using a photo etching technique in combination with the process. Since most of the manufacturing processes of the inductor 7 can be handled by the printing technology, the capital investment is relatively inexpensive. Further, since the size of the substrate can be easily increased, it is excellent in batch processing.

FIG. 7 shows an equivalent circuit of the inductor 7 of FIG. Here, a closed magnetic circuit 7-1, a first coil 7-2 for generating a magnetic field, and a second coil 7-3 used as a variable inductor are shown.

(Fourth Embodiment) FIG. 8 shows an inductor according to a fourth embodiment of the present invention. The inductor 8 of the fourth embodiment is particularly intended for use at high frequencies. In the high frequency range, wiring is well known,
It is expressed by inductance, capacitance, parallel conductance and DC resistance.

In the inductor 8 of the present embodiment,
A spiral first coil 8-2 is printed on the ceramic substrate 8-4. High permeability magnetic material substrate 8-1
Similarly, a second coil 8-3 is formed in a meandering pattern by patterning. These substrates 8-4 and 8-1 are attached as shown in the figure.

The manufacturing process of the inductor 8 uses not only the ceramic green process but also a photo-etch process.

When a bias current is applied to the first coil 8-2 in such a configuration in which the substrates 8-4 and 8-1 are bonded to each other, a magnetic field is generated, and a magnetic flux is induced in the magnetic substrate 8-1. The magnetic flux changes the inductance of the second coil 8-3.

FIG. 9 shows a parallel resonance circuit to which the inductor 8 of FIG. 8 is applied. In this parallel resonance circuit, a capacitor 8-5 is connected in parallel to the second coil 8-3.

The DC bias current I flows through the first coil 8-2.
When flow _bias, in response to the bias current I _{bi the as,} flux of high permeability magnetic material substrate 8-1 more permeability μ changes, the inductance of the second coil 8-3 along with this And the resonance frequency changes.

By arranging some of such parallel resonance circuits in parallel, various filters can be formed. By adjusting the resonance frequency of each parallel resonance circuit by the respective bias current, a desired filter can be obtained. Filter characteristics can be obtained.

FIG. 10 shows a series resonance circuit to which the inductor 8 of FIG. 8 is applied. In this series resonance circuit, a capacitor 8-5 is connected in series to the second coil 8-3. Also in this case, if the DC bias current _Ibias flowing through the first coil 8-2 is appropriately changed, the second coil 8
The inductance of -3 changes, and the resonance frequency changes.

FIG. 11 shows a matching circuit to which the inductor 8 of FIG. 8 is applied. This matching circuit is for matching the impedance of the strip line 11-1 for transmitting a signal.

In FIG. 11, a strip line 11-
The first coil 8-3 of the inductor 8 is inserted in 1. The input side of the second coil 8-3 is grounded via the capacitor 11-2.

In the matching circuit having such a configuration, when the load 11-3 of the resistor R is connected to the output side of the second coil 8-3, the matching of the input impedance Z _{in with} the output impedance is broken, and the reflected power is reduced. This causes a problem that the power loss increases. Particularly, in a high-frequency device, there is a problem that the matching of the input impedance Z _{in with} the output impedance is broken due to the influence of a person who uses the portable device, and in severe cases, communication becomes impossible.

When the matching of the input / output impedance is broken, the DC bias current I is supplied to the first coil 8-2.
By flowing _bias , the magnetic flux of the high-permeability magnetic material substrate 8-1,
Further, the magnetic permeability μ is changed, the inductance of the second coil 8-3 is changed, and the input impedance Z _in is changed to match the input / output impedance.

FIG. 12 shows another matching circuit to which the inductor 8 of FIG. 8 is applied. This matching circuit differs from the matching circuit of FIG. 11 in that the output side of the second coil 8-3 is grounded via a capacitor 11-2. To match.

(Fifth Embodiment) FIG. 13 shows a fifth embodiment of the present invention.
1 shows an inductor of an embodiment.

In the inductor 13 according to the fifth embodiment, a spiral first coil 13-2 similar to that shown in FIG. 8 is formed on a ceramic substrate 13-6, and a magnetic ceramic layer having a high magnetic permeability is formed thereon. 13-10 is formed and sintered, and then a meandering second coil 13-3 is formed. A signal input terminal 13-1 and a signal output terminal 13-4 are formed on a ceramic substrate 13-6, and a second coil 13-3 is inserted between the signal input terminal 13-1 and the signal output terminal 13-4. ing. A dielectric thin film 13-7 is sandwiched between the signal output terminal 13-4 and the conductive layer 13-9 to form a capacitor 13-
5, and one electrode of the capacitor 13-5 is connected to a ground metal plate 13-8 on the back surface of the ceramic substrate 13-6 via a through hole. The output side of the second coil 13-3 is connected to the signal output terminal 13-4 and the capacitor 13
Grounded through -5. 13-11 is SiO ₂ , A
This is an insulating film made of a material having a low dielectric constant such as l ₂ O ₃ .

The inductor 13 according to the fifth embodiment is different from the inductor 13 shown in FIG.
12 can be applied to the circuit of FIG. 12, and the capacitor 11-2 of FIG. 12 corresponds to the capacitor 13-5 of FIG.

(Sixth Embodiment) FIG. 14 shows a sixth embodiment of the present invention.
1 shows an inductor of an embodiment.

In the inductor 14 of the sixth embodiment, a spiral first coil 14-2 similar to that of FIG. 8 is formed on a ceramic substrate 14-6, and a magnetic ceramic layer having a high magnetic permeability is formed thereon. 14-10 is formed and sintered, and then a meandering second coil 14-3 is formed. A signal input terminal 14-1 and a signal output terminal 14-4 are formed on a ceramic substrate 14-6, and a second coil 14-3 is inserted between the signal input terminal 14-1 and the signal output terminal 14-4. ing. The dielectric thin film 14-7 is interposed between the signal input terminal 14-1 and the conductive layer 14-9 to form the capacitor 1
4-5 are formed, and one electrode of the capacitor 14-5 is connected to a ground metal plate 14-8 on the back surface of the ceramic substrate 14-6 via a through hole. Second coil 14-
3 is grounded via a signal output terminal 14-4 and a capacitor 14-5. 14-11 is Si
This is an insulating film made of a material having a low dielectric constant such as O ₂ and Al ₂ O ₃ .

The inductor 14 of the sixth embodiment is similar to that of FIG.
11 can be applied to the circuit of FIG. 11, and the capacitor 11-2 of FIG. 11 corresponds to the capacitor 14-5 of FIG.

FIG. 15 shows a patch-type antenna. 14 to the capacitor 14−
5, the inductor 14A is formed, a patch pattern 15-9 serving as an antenna is formed on the ceramic substrate 14-6, and the patch pattern 15-9 is connected to the second coil 14 via the signal output terminal 14-4. -3.

Also in such a configuration, when the matching of the input / output impedance is broken, the DC bias current _Ibias is supplied to the first coil 14-2, and the high permeability magnetic layer 14
The input / output impedance can be matched by changing the magnetic flux of −10, the magnetic permeability μ, the inductance of the second coil 14-3, and the input impedance Z _in .

Further, since it is possible to tune to a band having a different frequency, for example, tuning in the 1.5 GHz band and 1.9 GHz band, and correspondence to the analog / digital winding system in the 800 MHz band are performed by one circuit. Can be done.

FIG. 16 shows a patch antenna to which the inductor 14 of FIG. 15 is applied. Here, a patch array antenna 16 composed of a plurality of patch patterns 16-9 serving as antennas is formed on a ceramic substrate 14-6, and corresponding to each patch pattern 16-9, FIG.
Are provided.

The patch array antenna 16 having such a configuration
In the case where a signal having the same phase is input to each patch pattern 16-9 via each inductor 14A, the wavefront of the radio wave emitted from each patch pattern 16-9 has the same phase, Therefore, it has directivity in the vertical direction.

On the other hand, for example, each inductor 1
4A, the amount of bias current of the first coil 14-2 is sequentially changed from left to right in the drawing, and each inductor 14A
, The phase of the radio wave emitted from each patch pattern 16-9 can be changed, and the radio waves emitted from each patch pattern 16-9 interfere with each other to achieve variable directivity. Can be provided. That is, the first coil 14- of each inductor 14A
By controlling the amount of bias current of No. 2, the radio wave emission direction can be freely changed.
Further, if the patch array antenna 16 is divided into two, directivity in two directions can be given at the same time, the radio wave emission direction can be electrically scanned, and a tracking function can be given.

Here, the patch patterns are arranged in a line in a row. However, if the patch patterns are appropriately distributed on a two-dimensional plane or if the patch patterns are not in contact with each other, They may be arranged three-dimensionally.

(Seventh Embodiment) FIG. 17 shows a seventh embodiment of the present invention.
1 shows an inductor of an embodiment. In the inductor 17 of the seventh embodiment, a spiral first coil 17-2 is printed on a ceramic substrate (not shown). On the high-permeability magnetic material substrate 17-1, the second coil 17-3 is patterned in a meandering
One capacitor 17-5 is arranged. Two capacitors 17-5 are connected in series, and each capacitor 17-5 is connected in parallel to the second coil 17-3. The ceramic substrate and the high-permeability magnetic material substrate 17-1 are bonded together as shown in the figure.

When a bias current is applied to the first coil 17-2 in such a configuration in which the substrates are bonded to each other, a magnetic field is generated, and a magnetic flux is induced in the magnetic substrate 17-1. The inductance of the coil 17-3 changes.

FIG. 18 shows a voltage-controlled oscillator circuit to which the inductor 17 of FIG. 17 is applied.

In this voltage controlled oscillator circuit, each capacitor 17-5 is connected in parallel to the second coil 17-3 to form a resonance circuit. As mentioned earlier,
When a bias current flows through the first coil 17-2, the inductance of the second coil 17-3 changes, so that the resonance frequency of the resonance circuit changes, and accordingly, the oscillation frequency of the voltage-controlled oscillator circuit changes. Also change.

[0081]

As is apparent from the above description, while the characteristics of the high-frequency circuit have been mechanically adjusted in the past, the present invention reduces the inductance of the inductor by purely electrical control. Since the adjustment can be performed, the man-hour can be reduced, and at the same time, the reliability of the product is improved.

Further, according to the present invention, the inductance of the inductor can be electrically changed, an adjustable coil which has not been provided conventionally can be provided, and a new device can be provided.

If a resonance circuit comprising the inductor and the coil of the present invention is formed and this resonance circuit is incorporated in a resonance circuit or a filter, the resonance frequency can be adjusted or the filter characteristics can be adjusted by the bias current. Becomes This means that there is no problem with either the lumped constant circuit or the distributed constant circuit. Achieving impedance matching in a strip line that can be handled by a distributed constant circuit is an important issue in a high-frequency circuit. By applying the inductor of the present invention to a matching circuit, impedance matching can be achieved only by electrical processing, and failure can be prevented. Further, as a basic configuration, when a resonance circuit is configured by combining an inductance component and a capacitance component, the resonance frequency can be changed. From this point of view, since the transmission band is freely controlled, it can be said that the electric length of the electric signal to be handled (the electric length of the electric signal in the conductor) is changed. When the inductor of the present invention is used for an array antenna, it can be activated. Further, the directivity of the antenna can be adjusted. As described above, the application of the inductor of the present invention is very wide. Naturally, the use of the inductor in combination with the variable capacitance capacitor gives a further margin to the circuit design.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an inductor according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing an inductor according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of parallel resonance of the inductor and the capacitor shown in FIG. 2;

FIG. 4 is a graph showing a relationship between a magnetic field and a magnetic flux density of a closed magnetic circuit made of a material having a high magnetic permeability.

5 is a graph showing a slope (differential system) of a tangent of a characteristic curve of the closed magnetic circuit shown in FIG.

FIG. 6 is a cross-sectional view illustrating a structure of an inductor according to a third embodiment of the present invention.

FIG. 7 is a circuit diagram showing an equivalent circuit of the inductor of FIG. 6;

FIG. 8 is an exploded perspective view showing an inductor according to a fourth embodiment of the present invention.

FIG. 9 is a circuit diagram showing a parallel resonance circuit to which the inductor of FIG. 8 is applied.

FIG. 10 is a circuit diagram showing a series resonance circuit to which the inductor of FIG. 8 is applied.

FIG. 11 is a circuit diagram showing a matching circuit to which the inductor of FIG. 8 is applied.

FIG. 12 is a circuit diagram showing another matching circuit to which the inductor of FIG. 8 is applied.

FIG. 13 is a sectional view showing an inductor according to a fifth embodiment of the present invention.

FIG. 14 is a sectional view showing an inductor according to a sixth embodiment of the present invention.

FIG. 15 is a sectional view showing a patch antenna to which the inductor of FIG. 14 is applied.

16 is a perspective view showing a state where a plurality of the patch antennas of FIG. 15 are arranged.

FIG. 17 is a perspective view showing an inductor according to a seventh embodiment of the present invention.

18 is a circuit diagram showing a voltage controlled oscillator circuit to which the inductor of FIG. 17 is applied.

FIG. 19 is a view used to explain the principle of the inductor of the present invention.

[Explanation of symbols]

1,2,7,8,13,14,17 Inductor 1-1,2-1,7-1,8-1,13-1,14-
1,17-1 Closed magnetic circuit 1-2,2-2,7-2,8-2,13-2,14-
2, 17-2 First coil 1-3, 2-3, 7-3, 8-3, 13-3, 14-
3,17-3 2nd coil

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 5E070 AA05 AA20 AB01 BA12 BA14 BA20 CB03 CB12 CB13 CB20 DB08 EA01 MM02 5J021 AA02 AA05 AA09 AB06 CA03 CA06 DB03 EA04 FA06 FA32 GA02 HA01 HA02 HA03 HA05 HA10 5J02 CA0419 DA03 DA04 DA21 DA26 DA29 GA03 KA01 5J081 AA02 BB01 BB06 CC22 CC24 CC42 DD02 EE02 FF04 GG07 JJ02 KK02 KK11 KK22 LL02 MM01 MM06 MM09

Claims (10)

[Claims] 1. An inductor, comprising: a magnetic circuit made of a magnetic material; and a plurality of winding coils wound around the magnetic circuit. 2. The inductor according to claim 1, wherein the magnetic circuit is formed using at least one of a thick film magnetic material, a thin film magnetic material, and a bulk material. 3. At least one of said winding coils
A bias means for flowing a bias current to each of the first and second bias currents.
The inductor according to 1. 4. An electromagnetic field generated when a first element having an inductance component and a second element forming a bias coil surrounding a magnetic layer are supplied to the bias coil of the second element. And an inductor arranged to reach the first element. 5. A resonance circuit in which an inductance component and a capacitance component are connected in parallel or in series, wherein the inductor according to claim 1 is applied as the inductance component. A resonance circuit for supplying a bias current to at least one of the resonance circuits; 6. The resonance circuit according to claim 5, wherein the resonance frequency is arbitrarily changed by using both the variation of the inductance component by the bias current and the variation of the capacitance component by applying a voltage to the capacitance component. 7. The resonance circuit according to claim 5, wherein a plurality of resonance frequencies are selectively set by changing the bias current. 8. A matching circuit in which the inductor according to claim 1 is incorporated in at least one of the impedances so as to match the input impedance and the output impedance. 9. An antenna circuit in which a plurality of antenna elements are arranged, wherein an input / output circuit for each of the antenna elements includes:
An antenna circuit incorporating each of the inductors according to claim 1. 10. An oscillating circuit including an inductance component and a capacitance component connected in parallel or in series, wherein the inductor according to claim 1 is applied as the inductance component. An oscillation circuit that supplies a bias current to at least one of the circuits.