JPH09270605A - Resonator and yig device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the resonator whose parasitic resonance is suppressed with improved uniformity of a high frequency magnetic field generated by a coupling coil. SOLUTION: Coupling coils 12a, 12b are formed by winding a gold wire whose diameter is 50μm to be a form of a semi-circle whose diameter is 0.9mm by a half turn and they are arranged coaxially apart by L=0.45mm opposite to each other. An Yttrium Iron Garnet(YIG) element 4 is placed in the middle between the coupling coils 12a, 12b on an axial line and is the same as a conventional element (0.5mmϕ).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonator used in a YIG (yttrium iron garnet) device that constitutes an oscillator or a filter in a microwave frequency band.

[0002]

2. Description of the Related Art YIG devices are yttrium, iron,
This is a device for a tunable resonator / oscillator in the microwave band, which utilizes the characteristics of Garnet's three-metal ferrimagnetic resonance having a very high Q.

FIG. 7 is a cross-sectional view of a conventional YIG device,
FIG. 8 (1) is a plan view of the resonator portion, FIG. 8 (2) is a side view of the resonator portion, and FIG. 9 is 3.8 to 4.2 GH of this resonator.
It is a figure which shows the reflection characteristic in z.

As shown in FIG. 7, in the YIG device, the open surface of the upper portion of the pot-shaped magnetic core 1 having the central axis 2 is covered with a plate-shaped magnetic core 3, and the tip surface of the central axis 2 and the plate-shaped magnetic core 3 are covered. The YIG element 4 is arranged between the magnetic core 3 and the magnetic core 3. YIG
The element 4 is attached to one end of the support rod 5 parallel to the inner surface of the plate-shaped magnetic core 3. The other end of the support rod 5 is fixed to the inner surface of the plate-shaped magnetic core 3 with a fixture 6.

A hybrid integrated circuit board 7 is also fixed to the inner surface of the plate-shaped magnetic core 3. On the hybrid integrated circuit board 7,
A semi-circular (0.9 mmφ) coupling coil 8 is attached so that the YIG element 4 (0.5 mmφ) is located at the center (FIG. 8).

When constructing an oscillator, although not shown, an oscillation circuit having a YIG element 4 as a resonator is formed, and an amplifier of the oscillation output is formed on the hybrid integrated circuit board 7 for use. .

A coil 9 is formed around the central axis 2, and a DC voltage is applied to the coil 9 from a power supply terminal 10 to
A magnetic field can be applied to the YIG element 4 by passing a current therethrough. By applying this magnetic field, the YIG element 4 resonates and can be made to act as an oscillator.
Then, the oscillation output is output to the outside from the coaxial connector 11 attached to the plate-shaped magnetic core 3. YIG element 4
Since the resonance frequency of is proportional to the strength of the magnetic field, a desired resonance frequency can be obtained by controlling the current flowing through the coil 9.

The YIG device is mainly used for local oscillators and filters of spectrum analyzers and network analyzers, and is an important component that influences the performance of these measuring instruments. Therefore, in order to improve their performance, the characteristics of YIG devices have been improved.

[0009]

The resonance characteristics of the YIG device are determined by the YIG element 4 and the coupling coil 8 which form the resonator. That is, when the crystal lattice of the YIG element 4 is defective, is not a perfect sphere, or the high frequency magnetic field generated by the coupling coil 8 is not uniform, Y
The precession motion of the spins inside the IG element 4 becomes non-uniform, which appears as deterioration of RF characteristics such as deterioration of Q, generation of spurious, generation of parasitic resonance (FIG. 9). In order to prevent this, it is conceivable to complete the growth of the YIG element 4 crystal and the processing into a sphere. However, it is very difficult to manufacture the YIG element 4 of higher quality than at present. Therefore, by devising the coupling coil 8 side,
It is desired to prevent deterioration of RF characteristics.

Further, in recent measurement applications such as digital communication, there is a demand for analyzing a short-time spectrum such as a burst-like signal, and there is an increasing need for frequency sweeping of the YIG device at a higher speed.
Conventionally, the space between the pot-shaped magnetic core 1 and the plate-shaped magnetic core 3 has been made narrower. By reducing the number of windings of the coil 9 for generating the same magnetic field and reducing the inductance, high-speed frequency sweeping is possible. Usually, the resonator (YIG element 4, coupling coil 8), the hybrid integrated circuit board 7 and the like must be mounted in this space, and therefore the resonator itself must be miniaturized in order to narrow the space. However, it is very difficult to reduce the size of the currently used resonator further than the current one in order to maintain the characteristics.

An object of the present invention is to provide a resonator in which the high-frequency magnetic field generated by the coupling coil has good uniformity and parasitic resonance is suppressed.

Another object of the present invention is to provide a small resonator while maintaining the performance equivalent to that of a conventional coupling coil.

[0013]

In the resonator of the present invention, two coupling coils having the same shape are coaxially opposed to each other with a certain distance.

According to the present invention, the coupling coil of the resonator portion of the YIG device is arranged such that two loops are coaxially opposed to each other, rather than the conventional simple loop. By doing this, the homogeneity of the high frequency magnetic field generated by the coupling coil is improved, and the parasitic resonance of the resonator is suppressed,
Thereby, the deterioration of the RF characteristics of the YIG device can be prevented.

Since this modification only changes the structure of the coupling coil portion, the conventional components can be used as they are, and can be easily used in the current YIG device. Therefore, it is possible to easily improve the performance of the conventional spectrum analyzer and the like.

In the resonator of the present invention, a part of the two coupling coils is embedded in the cutout portion of the substrate.

Therefore, it is possible to downsize the resonator itself while maintaining the performance equivalent to that of the conventional coupling coil. As a result, the gap between the magnetic cores can be made narrower, and a compact YIG device capable of high-speed frequency sweep can be manufactured. This YIG
By mounting the device on a spectrum analyzer or the like, the frequency can be swept at a higher speed for spectrum analysis, so that the device can be applied to applications such as recent digital wireless communication devices. In addition, the downsizing of the YIG device has the advantage that the downsizing of the measuring instrument and the reduction of power consumption can be realized at the same time.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a plan view and a side view of a resonator portion of a YIG device resonator according to a first embodiment of the present invention.

In this embodiment, coupling coils 12a and 12b are used.
Is a gold wire with a diameter of 50 μm processed into a half-circle with a diameter of 0.9 mm into ½ turns, and is coaxially separated by L = 0.45 mm from each other so that the homogeneity of the high frequency magnetic field is the best. It is arranged facing each other. The YIG element 4 is located at an intermediate point on the axes of the coupling coils 12a and 12b and is the same as the conventional one (0.5 mmφ).

FIG. 2 shows coupling coils 12a and 1 having a radius of 1 mm.
2b is a diagram showing a magnetic field distribution generated on the central axis thereof. FIG. The vertical axis represents the relative magnetic field strength when the magnetic field strength when L = 0 is 1, the horizontal axis represents the coordinates on the central axes of the coupling coils 12a and 12b, and 0 represents the coupling coils 12a and 12b.
Corresponds to the center point between. In FIG. 2, the positions 1 of the coupling coils 12a and 12b are 0, ± 0.2 mm, and ± 0.4, respectively.
mm, ± 0.6 mm, ± 0.8 mm, ± 1.0 mm, ±
The magnetic field distribution is shown for the case of 0.5 mm.

From the center point, the coupling coils 12a and 12b are +
When arranged at the points of 0.5 mm and -0.5 mm, the homogeneity of the magnetic field becomes the best. When the coupling coils 12a and 12b are brought close to each other from a position of ± 0.5 mm, the magnetic field distribution becomes mountainous, and when the interval is 0, the magnetic field homogeneity becomes the worst. In addition, the coupling coils 12a and 12b are ± 0.5 m
When moving away from the position of m, the magnetic field distribution forms a valley at the center.

In the above, an example in which the dimensions are specifically increased is shown, but the uniformity is not limited to this example. It has been found that when the radii of the coupling coils 12a and 12b are D, and the two coupling coils 12a and 12b are arranged at a distance D, the homogeneity of the magnetic field is maximized.

According to this embodiment, the high frequency magnetic field can be made more uniform than the conventional one, and as a result, parasitic resonance can be suppressed as shown in FIG.

FIG. 3 is a diagram showing the reflection characteristics of the resonator for the YIG device of this embodiment at 3.8 to 4.2 GHz.

Almost no distortion is seen in the reflection characteristics (FIG. 9) of the conventional resonator for YIG device. In the case of an oscillator, distortion of the reflection characteristic appears as parasitic oscillation, and it can be seen that the parasitic resonance is suppressed by the absence of distortion.

4 (1) and 4 (2) are a plan view and a side view of a resonator portion of a resonator for a YIG device according to a second embodiment of the present invention.

In this example, a gold wire having a diameter of 50 μm was processed into a circle having a diameter of 0.7 mm by winding 1.5 turns.
The individual coupling coils 13a and 13b are coaxially opposed to each other at a distance of L = 0.35 mm so that the homogeneity of the magnetic field is maximized. The YIG element 4 is located at the midpoint on the two axes. The YIG element 4 is the same as the conventional one (0.5 mm). As a result, while using the YIG element 4 having the same diameter as the conventional resonator, the diameter of the resonator is changed from the conventional 0.9 mm in FIG.
This means that the size can be reduced to 7 mm. Further, in the case of this embodiment, the height can be further suppressed by cutting the hybrid integrated circuit board 7 and embedding the lower side of the coil in the hybrid integrated circuit board 7 as shown in FIG. 4B. The substantial height of the resonator is about half that of the conventional one. As described above, since the height of the resonator can be suppressed, the interval between the magnetic cores 1 and 3 can be narrowed and the frequency sweep speed can be tripled as compared with the conventional one. Also, the volume of the coil 9 could be reduced to 1/5 of the conventional volume.

In FIG. 5, the radius of the coupling coils 13a and 13b is 0.8 mm, and the point where the magnetic field is most uniform is l = ±.
The magnetic field distribution when arranged at 0.4 mm is shown.
The other line is the data of FIG. 5 (coupling coil with a radius of 1 mm). It can be seen that although the magnetic field is narrowed by the downsizing, the magnetic field has a sufficient magnetic field homogeneity as compared with the conventional one.

Therefore, even if the diameter of the loop of the conventional coupling coil is made smaller, the homogeneity of the high-frequency magnetic field is improved, so that the same performance as the conventional one can be exhibited.

FIG. 6 shows the resonator of 3.8 to 4.2 GH.
It is a figure which shows the reflection characteristic of z. It can be seen that the characteristics are almost the same as those of the conventional resonator (FIG. 9). When actually oscillating, the conventional resonator oscillates in the band of 3.5 GHz to 8.3 GHz, but in this resonator,
It oscillated at 8.9 GHz and no deterioration in performance was observed.

In the above embodiments, the shape of the coupling coil is semicircular or circular, but it is not limited to this. Also, the resonator of the present invention can be used in devices other than YIG devices.

[0033]

As described above, the present invention has the following effects. (1) According to the first aspect of the present invention, by using two coupling coils facing each other, the high frequency magnetic field applied to the YIG element can be made uniform, thereby reducing parasitic resonance. (2) According to the invention of claim 2, the gap of the magnetic circuit (interval between the magnetic cores) is made smaller than the conventional one by embedding a part of the two coupling coils facing each other in the notch of the substrate. The resonator can be made compact.

[Brief description of drawings]

FIG. 1 is a plan view and a side view of a resonator portion of a resonator for a YIG device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of the coupling coils 12a and 12 in the first embodiment.
3B is a graph showing a magnetic field distribution generated on the central axis thereof.

FIG. 3 is a diagram of a resonator for a YIG device according to the first embodiment.
It is a figure which shows the reflection characteristic in 8-4.2 GHz.

FIG. 4 is a plan view and a side view of a resonance portion of a YIG device resonator according to a second embodiment of the present invention.

FIG. 5: Coupling coils 13a, 13 in the second embodiment
FIG. 7B is a diagram showing a magnetic field distribution generated on the central axis of the magnetic field.

FIG. 6 is a diagram of the YIG device resonator according to the second embodiment.
It is a figure which shows the reflection characteristic in 8-4.2 GHz.

FIG. 7 is a cross-sectional view of a conventional resonator for a YIG device.

8 is a front view and a side view of a resonator portion of the YIG device resonator of FIG. 7. FIG.

9 is a schematic diagram of a resonator for a YIG device of FIG.
It is a figure which shows the reflection characteristic in 2 GHz.

[Explanation of symbols]

 1 Vase-shaped magnetic core 2 Central axis 3 Plate-shaped magnetic core 4 YIG element 5 Support rod 6 Fixture 7 Hybrid integrated circuit board 8 Coupling coil 9 Coil 10 Power supply terminal 11 Coaxial connector 12a, 12b Coupling coil 13a, 13b Coupling coil

Claims (3)

[Claims] 1. A resonator, wherein two coupling coils having the same shape are coaxially opposed to each other with a certain distance therebetween. 2. The resonator according to claim 1, wherein a part of the two coupling coils is embedded in a cutout portion of the substrate. 3. A YIG device having the resonator according to claim 1.