JPH0313113A - Magnetostatic wave device - Google Patents

Abstract

PURPOSE:To enlarge the range of a frequency, which can be tuned, by widening the width of an input/output electrode gradually toward a tip in a lengthwise direction. CONSTITUTION:An input electrode 1 and an output electrode 2 are provided to be arranged closely to the surface of a magnetic film 4. The input and output electrode 1 and 2 are connected to the respective tips of microstrip lines 10 and 20 and formed so that the width can be widened gradually toward the tip of each electrode part. Because the electrode itself is equipped with various frequency characteristic corresponding to the width of the electrode and a magnetic wave device composed of the electrode is also equipped with a low value over the wide frequency range for inserting loss at the time of resonating the magnetostatic wave device whose tunable frequency range extended to the high frequency band is obtained.

Description

[Detailed Description of the Invention] [Summary] Regarding the element structure of a magnetostatic wave device, for the purpose of widening the tunable frequency range of a magnetostatic wave device, especially a magnetostatic wave filter, a magnetic film and a magnetic film surface that are close to each other are used. an input electrode and an output electrode arranged so as to
In a magnetostatic wave device comprising at least an external magnetic field applying means, the input electrode and the output electrode are connected to respective tips of two microstrip lines, and
A magnetostatic wave device is constructed by forming the width of each electrode portion to become wider as it approaches the tip.

[Industrial Field of Application] The present invention relates to element configurations used in magnetostatic wave devices, such as microwave band filters, resonators, delay lines, etc., and particularly to electrode shapes.

In recent years, with the increase in the capacity and speed of data transmission, G
Development of H2 band filters, resonators, delay lines, etc. is progressing.

Magnetostatic wave devices that apply the magnetic resonance of magnetic materials have good characteristics in the GHz band, and can be controlled over a wide range of frequencies by changing the externally applied magnetic field.

It has the characteristic that the delay time etc. change. These characteristics are useful in the design of electronic circuits in high frequency bands, and new applications are opening up, and there is a growing demand for improved characteristics.

[Conventional technology]

A so-called YIG filter, which is a magnetostatic wave device that uses the magnetic resonance characteristics of yttrium-iron-garnet (YIG) spheres and can significantly change the resonant frequency by changing the externally applied magnetic field, has been known. However, this device had drawbacks such as being difficult to process the YIG ball, assembling and adjusting the device, and being expensive.

In contrast, recently, many magnetostatic wave devices, which are solid-state elements with a thin film structure that are more compact, easier to manufacture, and highly reliable, have been proposed.

Figure 6 shows a typical example of such a thing.
FIG. 2 is an exploded perspective view of a conventional magnetostatic wave device.

In the figure, 40 is a substrate for a magnetic film, for example, gadolinium gallium garnet (GGG), 4 is a magnetic film,
For example, YIG with low magnetic loss is formed on the GGG substrate 40 by liquid phase epitaxial (LPE) method.
It is a membrane. 6 is a brass block that constitutes the base of the device and is used as a ground. 5 is an alumina ceramic substrate, 10' and 20' are microstrip lines forming power supply lines to the input and output electrodes. 6 1' and 2' are input electrodes and output electrodes, which are microstrip lines 10' and 20, respectively. ' are arranged in parallel at a certain distance apart, and the width of each electrode is constant as shown in the figure.

3 is a glass spacer, and a magnetic film 4 and input/output electrodes 1' and 2' are stacked with this glass spacer 3 in between to form an element. Note that the glass spacer 3 is not always necessary, and in some cases, the input/output electrodes 1゛, 2° may be connected to the magnetic film 4.
It may also be configured by bringing them into close contact with each other.

Further, an arrow H0C in the figure indicates an external DC applied magnetic field, which is constructed so that a variable magnetic field can be applied as required by a permanent magnet or an electromagnet (not shown).

Note that ) Ioc is applied parallel to the magnetic film 4 and perpendicular to the traveling direction of the magnetostatic wave. The so-called MSSW (Ma
gnetic 5tatic 5urface Wav
e) mode (surface wave mode).

FIG. 5 is a diagram showing the frequency characteristics of a magnetostatic wave filter. For example, when an externally applied magnetic field H1,c is applied to the configuration shown in FIG.
This figure shows the resonance characteristics when changing in the range of 0.93 to 2.61 kOe. The resonance frequency is Ho. It is variable, and changes at a rate of about 2.8 MFlz10e.

Insertion loss can be obtained in the frequency range of 5 dB or less, but it is not constant over the entire frequency range, and
That is, there is a direction in which the insertion loss becomes large in the low frequency region and in the region where I(DC is large, that is, the high frequency region).

The measurements were carried out in accordance with the usual method using a network analyzer with the microstrip line 10' as the input end and the 20' microstrip line as the output end.

[Problem to be solved by the invention]

FIG. 4 is a frequency characteristic diagram of insertion loss during resonance in a conventional example, where the vertical axis represents insertion loss and the horizontal axis represents frequency.

In the figure, ■ indicates an input/output electrode with a length of 1° and 2° of 4 mm and a width of 0.
．． In the case of 36mm, ■ also has a length of 4mm.

If the width is 2mm, ■ also has a length of 4mm and a width of 3mm.
This is the case of mm. ) Inc 0, 93kOe to 4
The resonance characteristics were measured by changing up to kOe, and the insertion loss at each center frequency was plotted.

That is, in the above conventional example, the smaller the input/output electrode width, the lower the region of insertion loss is on the low frequency side, and the larger the input/output electrode width, the lower the region of insertion loss tends to shift toward the higher frequency side. In all cases, the insertion loss increases rapidly between 10 and 11 GHz.

Moreover, as the input/output electrode width increases, the rise of insertion loss on the low frequency side also shifts toward the high frequency side, so in the end,
As the width of the input/output electrodes increases, there is a problem in that the region with low insertion loss becomes narrower, and a solution to this problem is needed.

[Means to solve the problem]

The above problem is solved in a magnetostatic wave device that includes at least a magnetic film 4, a manual electrode l and an output electrode 2 arranged close to the surface of the magnetic film 4, and external magnetic field applying means.
The input electrode 1 and the output electrode 2 are connected to the respective tips of the microstrip lines 10 and 20, and the width becomes wider as it approaches the tip of each electrode portion. be able to.

[Effect]

In the magnetostatic wave device of the present invention, the width of the input/output electrode is made wider toward the tip in the length direction, so that the electrode itself has various frequency characteristics corresponding to the electrode width. Magnetostatic wave devices also have wide frequency characteristics.

〔Example] FIG. 1 is a perspective view of an apparatus according to an embodiment of the present invention.

In the figure, 40 is a magnetic film substrate, for example, 0.5 m thick.
A mirror-finished GGG single crystal plate having a (111) plane of m, 4 is a magnetic film, for example, formed on the GGG substrate 40 by a liquid phase epitaxial (LPE) method and having a thickness with small magnetic loss. It is a 20 μm YIG film. 5 is a brass block with a thickness of 5 mm and a size of 1010 x 20.
It forms the base of the device and is used as a ground. 5 has a thickness of 0.4 mm and a size of 1010 x 20
Alumina ceramic substrates, 10 and 20 have a width of 0.3
A 50Ω microstrip line made of Au with a thickness of 6mm and 8μm forms the feeder line to the input/output electrodes, and in order to make it, for example, Au is coated with a thickness of 50Ωm on the alumina ceramic substrate 5. After vapor deposition and photoetching to form a microstrip line pattern, Au plating is performed to form a predetermined thickness.

1 and 2 are input electrodes and output electrodes, which are connected to the tips of microstrip lines 10 and 20, respectively;
The long sides of the opposing electrodes are arranged in parallel with a distance of 6 m apart, the length of the electrode part is 4 mm, the width of the connection part with the microstrip line is 0.36 mm, and the widest tip part The width is 3 mm, and the oblique side is a straight line. The electrode material is Au, which is the same as the microstrip line, and has a thickness of 8 μm, and is formed at the same time as the microstrip lines 10 and 20 by the same process.

3 is a glass spacer, which is used to suppress spurious on the high frequency side of the filter characteristics; in this example, a glass plate with a thickness of 200 μm is used, and it is inserted into the magnetic film 4 with the glass spacer 3 in between. The output electrodes 1.2 are stacked to form a device.

Note that the glass spacer 3 is not necessarily required, and the input/output electrodes 1 and 2 may be configured in close contact with the magnetic film 4 depending on the case.

Further, the arrow HIlIC in the figure indicates an external DC applied magnetic field, and the knee is configured so that a variable magnetic field can be applied as necessary by a permanent magnet or an electromagnet (not shown).

Note that HDC is applied parallel to the magnetic film 4 and perpendicular to the direction of propagation of the magnetostatic wave. The case of the so-called MSSW mode (surface wave mode) is shown.

FIG. 2 is a diagram showing an example of the input/output electrode pattern of the present invention, and the example (part 1) in FIG. The hypotenuse is made up of straight lines. On the other hand, in the embodiment (part 2) shown in FIG. 12(b), the electrode arrangement is the same as that in the embodiment (part 1), but the oblique side is curved, for example, changed exponentially. Of course, the shape of the curve is not limited to exponential, and may be any other curve, as long as it becomes wider toward the tip of the electrode and the frequency characteristics of insertion loss at the resonant frequency become wider. good.

Also, in all of the above embodiments, the wider end of the input/output electrode is arranged diagonally, but ha! 'Similar effects can be obtained by symmetrical arrangement such that they are on the same line.

FIG. 3 is a frequency characteristic diagram of the insertion loss at resonance of the embodiment "Jl" of the present invention, which is the measurement result of the embodiment device explained in detail in FIG. 1. The device mode is MS mode,
The resonance characteristics were measured while changing the externally applied magnetic field HDe from 0.93 kOe to 5 kOe, and the insertion loss at each center frequency was plotted.

The measurement was carried out according to the usual method using a network analyzer with the microstrip line 10 as the input end and the microstrip line 20 as the output end.

As can be seen from the figure, the insertion loss is 7 dB or less over a wide frequency range from 7 to 13 GHz, which is a significant improvement compared to the conventional example shown in Figure 4.
A magnetostatic wave device with extended tuning range to high frequency bands was obtained.

〔Effect of the invention〕

As described above, according to the present invention, the width of the input/output electrode is made wider toward the tip in the length direction, and the electrode itself has various frequency characteristics corresponding to the electrode width.
Since the magnetostatic wave device constructed thereby also has a low insertion loss during resonance over a wide frequency range, it greatly contributes to improving the performance and quality of the magnetostatic wave device in the GHz band.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the device of the present invention, Fig. 2 is a diagram showing an embodiment of the input/output electrode pattern of the present invention, and Fig. 3 is the frequency characteristic of insertion loss at resonance of the embodiment of the device of the present invention. 4 is a frequency characteristic diagram of insertion loss at resonance in a conventional example, FIG. 5 is a diagram showing frequency characteristics of a magnetostatic wave filter, and FIG. 6 is an exploded perspective view of a conventional magnetostatic wave device. In the figure, 1 is a manual electrode, 2 is an output electrode, 3 is a glass spacer, 4 is a magnetic film, 5 is an alumina substrate, 6 is a brass block, 10.20 is a microstrip line, and 40 is a magnetic film substrate. 5. Perspective view of an embodiment of the device of the present invention.10.
Figure 62- Meeting 7! ,, Umii0 Σ

Claims (1)

[Scope of Claims] A static device comprising at least a magnetic film (4), an input electrode (1) and an output electrode (2) disposed close to the surface of the magnetic film (4), and external magnetic field applying means. In the magnetic wave device, the input electrode (1) and the output electrode (2) are connected to the respective tips of the microstrip lines (10) and (20), and the width thereof increases as it approaches the tip of each electrode portion. A magnetostatic wave device characterized by being formed to have the following characteristics.