JPS62245705A - Ferromagnetic resonator - Google Patents

Abstract

PURPOSE:To strengthen the coupling between a line and a ferromagnetic thin film without changing the thickness of a dielectric in use, the dielectric constant and the arrangement of line by selecting a larger characteristic impedance of an input line at the input terminal and decreasing the characteristic impedance smaller at the coupling part with the ferromagnetic thin film. CONSTITUTION:The ferromagnetic thin film 15 receiving a magnetic field perpendicularly at film face and the input line 13 coupled with the thin film 15 are provided, and the input line 13 has the 1st characteristic impedance at an input terminal 13B and has the 2nd characteristic impedance smaller than the 1st characteristic impedance at the coupling part 13 with the film 15. The characteristic impedance of the input line 13 is selected to be larger at the input terminal and to be smaller at the coupling part with the film 15. Thus, the coupling between the input line 13 and the thin film 15 is strengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ferromagnetic resonance apparatus using a ferromagnetic thin film in which a magnetic field is applied perpendicularly to the crotch.

[Summary of the invention]

The present invention relates to a ferromagnetic resonance device, in which an input line is coupled to a ferromagnetic thin film to which a magnetic field is applied perpendicularly to the magnetic field. By having a second characteristic impedance smaller than the first characteristic impedance at the coupling part with the line, the coupling between the line and the ferromagnetic thin film is strengthened without changing the thickness of the dielectric used, the dielectric constant, or the arrangement of the line. By doing so, it is possible to reduce insertion loss and expand its 3 dB bandwidth.

[Conventional technology]

Hitherto, a mass-producible thinned YIG filter (ferromagnetic resonance device) using a YIG thin film and a strip line has been proposed (for example, Japanese Patent Laid-Open No. 103403/1983). An example of a conventional ferromagnetic thin film filter to be compared with the present invention will be explained with reference to FIG. FIG. 7A is a plan view of this filter, and FIG. 7B is a sectional view taken along the line bb. This is a one stage filter. (11) is a quartz substrate as a dielectric substrate, the back surface of which is grounded and conductive.
iii (12) is coated on the entire surface. An output side microstrip line (conductive J't#) (14) is deposited on the center of the surface of this quartz substrate (11), and its negative end is extended and the ground conductive 1+# (1
2) is connected (shorted). (14a) is the shorted end of this output side microstrip line (14).

(17) is a GGC; (gadolinium gallium garnet) plate, one of which is mainly grown by the liquid phase epitaxial method, and the YIGHM is grown by the liquid phase epitaxial method. 15), and this YIG)i film (15) is placed in close contact with the vicinity of the short-circuited end (14a) on the output side microstrip line (14). An input end microstrip line (13) is formed on the main upper side of this GGC plate (17) in the h direction, facing the YIG thin II (15) and intersecting with the output side microstrip line (14). , one end of which is extended and connected (short-circuited) to the ground conductive layer (12).

(13a) is the input end microstrip line (13)
At the short-circuited end of , near this end (13a), yrc thin 19! (15) are made to face each other.

The input and output side microstrip lines (1: (
) and (14) both have a characteristic impedance of 50Ω.
Taking into consideration the interposition of each line (13), (14) and the ground conductor between w4 (12) and (11) and GC:Gi (17), the width of the valley is Selected.

Also, input and output side microstrip line (13)
, (14) are each equipped with a connector (not shown), and the microstrip line (13) on the input and output sides is connected via these connectors.

(14) is connected to an external circuit.

As shown in FIGS. 8 and 9, the opposing permanent magnets in the magnetic yoke Y of the magnetic device are /1 (19).

(20) Insert the filter shown in Figure 7 within the gap CP between
Arrange it as shown in the figure, Y I G8 test (15), due to its ferrimagnetic resonance, on the film surface! By applying a uniform bias direct current magnetic field at 1E, a fixed filter device of °C1 can be obtained. Also, as shown in Fig. 1θ, there are permanent magnets 1 (I'll) in the magnetic yoke Y,
(20) and an electromagnet (19B) that can vary the generated magnetic field.
), (20B) by placing the filter shown in FIG. 7 in the gap GP of the magnetic device, a narrow band jS ro J-variant filter device can be obtained.

When such an N-crotch ylG filter is used in the microwave band, the Q is quotient, the resonance frequency does not depend on the volume of the YIG@magnetic material, and the resonance frequency can be varied over a wide band by varying the strength of the bias magnetic field. Can be varied linearly, and YIG
Since photolithography technology can be used to form the I model, mass production is high, there is little variation in characteristics, and fM
It has the advantage of having 61 sub-adjustments and being inexpensive.

[Problem that the invention seeks to solve]

By the way, in such a conventional ferromagnetic resonance device, input and output lines (input and output side microstrip lines (
13) The characteristic impedance of (14) is outside!
In consideration of impedance matching with 'fB [1111ffi, it was set to a relatively large value of, for example, 50Ω.

Therefore, in a conventional ferromagnetic resonance device, each line (13)
, (14) and the ferromagnetic thin film (15) becomes weak, resulting in an increase in insertion loss.

In order to solve this problem, dielectric base number (11) and GGC
The thickness of the plate (17) is reduced to increase the electric flux density of the electric field and the magnetic flux density of the magnetic field from the output line (14) to the ground conductive layer (12), thereby increasing the output line (14) and the ferromagnetic thin II (15) may be considered, but for input line II (13), the ferromagnetic Wl film (
15) is located on the side where magnetic flux is not concentrated, and the coupling becomes weaker on the contrary.

Addressing these points, the present invention provides a method for forming lines and ferromagnetic 81 without changing the thickness, dielectric constant, or arrangement of the dielectric used.
This paper attempts to propose a ferromagnetic resonance device that can increase the insertion loss and its 3 dB bandwidth by strengthening the coupling between the two.

(Means for Solving the Problems) The ferromagnetic resonance device according to the present invention includes a ferromagnetic thin 1iJ (15) to which a magnetic field is applied perpendicular to the film surface, and a ferromagnetic thin
I! (15), and this input line (13) is connected to its input end (13B).
), and has a second characteristic impedance smaller than the first characteristic impedance at the coupling part (12C) with the ferromagnetic component 1'E (15). It is.

[Effect]

According to the present invention, the characteristic impedance of the input line (13) is large at the input end, and the ferromagnetic component FJ (
15) is selected to be small, so that the coupling between the input line (13) and the ferromagnetic H sliding door Hs) is strengthened.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIGS. 1, 2, and 3. This is a two-stage filter. (11) is a dielectric substrate; this quartz substrate (0,3
m+-thickness), and a ground conductive layer 1-(12) is deposited on the entire surface of the back surface. Input and output side microstrip lines (conductive layers) (13 ), (14)
are deposited and each end facing away from the housing is open. (13A) and (14A) are the open ends of the microstrip lines (13) and (14), respectively.

(17) is a GGG (gadolinium gallium garnet) plate (0.4 mm thick), on which a YIG thin film grown by the liquid phase epitaxial method is grown using photolithography, and the thickness is 15μ steel. is 1.5m-
A disk-shaped YIG thin film (15), (16) is formed, and each YIG thin film (15), (16) is connected to an input and output side microstrip line (13).

The upper open ends (138) and (14^) of (14) are placed in close contact at a distance of a characteristic described later.

On the other main surface of this GGG plate (17), a YIG thin film (
A connecting microstrip line (18) is formed so as to face the microstrip lines 15) and (16) and intersect the input and output side microstrip lines (13) and (14), and both ends thereof are open. (18A).

(18B) are both open ends of the microstrip line (18).

Then, connect the input and output side microstrip lines (1
3) Input and output terminals (13B) of (14).

The characteristic impedance of (14B) is set to 50Ω, for example, and the coupling part (13B) with YIC thin crotch C15) and (16)
c) Set the characteristic impedance of (14G) to 30Ω.

In this case, input and output microstrip lines (
13) The characteristic impedance of the portion (7.5 mm) from the edge of the dielectric substrate (11) in (14) to the edge of GGG & (17) is from the edge of dielectric substrate (11) to GGG
For example, from 50Ω to 30Ω as you go to the edge of (17)
Input and output side microstrip lines (13), (14) and ground ring so that Ω gradually decreases?
T! #p, 'f! between jtf(12)! t1 body board (11
), the width of each part is set to 0.64 to 1.
Set it to 36+w+w and make both sides tapered. In addition, input and output side microstrip lines (1
3) Input and output microstrip lines (13) so that the characteristic impedance of the portion spanning between both edges of GGG & (17) in (14) is constant, for example, 30Ω.

(14) and the dielectric substrate (11) between the ground conductive layer (12)
), the width is set to a constant @ (1,021
m11). In addition, the dielectric base & (11) and GGG between the connecting microstrip line (18) and the ground conductive layer (12) are arranged so that the characteristic impedance of the connecting microstrip line (18) is constant at 50Q.
Considering the intervention of the plate (17), its width is set to a constant width of 0.7
Set to 9++-.

Then, the filters shown in FIGS. 1, 2, and 3 are
Gap C of the magnetic device in Figures 8 and 9 or Figure 1θ
Placed inside P, YIG thin 151! (15).

(16), due to its ferrimagnetic resonance, is subjected to a uniform bias DC magnetic field perpendicular to its installation surface to obtain a fixed or variable filter device. Here, the bandpass center frequency is, for example, 13.0 GIlz.

Then, the input and output side microstrip lines (1
3) , (1,1)! I, the physical length of the part facing J) is the transmission wavelength 1'a of the signal in the passband, λ.
An integer multiple of approximately 1/2 of , in this case, λ/2 is selected.

Historically, in this example, the microstrip line 13) (1
4) and (]8) each open end (138), (148)
and the physical length from the center of circular YIG thin films (15) and (16) of (18^) and (18B), respectively)
a.

b, c, and d are all selected to be odd multiples of approximately 1/4 of the propagation wavelength λ of the signal in the passband, here λ/4.

Historically, input and output side microstrip lines (13
), (14) is substantially equal to the center-to-center distance of the conical ytc book jQ(15), (16), here 2.2 mva'J is the propagation wavelength λ of the signal in the passband. Approximately 1/2 or more (preferably approximately λ/4 or less), here approximately λ/4 is selected. In this case, both YIG
? As long as direct bonding between the i-films (15) and (1B) does not occur, it is preferable that the distance c be small.

Next, the operation of such a filter will be explained. When a high frequency signal with a propagation wavelength λ is supplied to the input side microstrip line (13), the high frequency signal is transmitted to the open end (13A) of the input side microstrip line (13).
), but at the open end, the voltage is maximum, the current is minimum (':@''), and the magnetic field is minimum (zero).On the other hand, the length from the open end (13A) to the YIG thin film (15) is the note selected as described above, Y I G 'A'ine
(15) (D center (17, position 4; 1: Conversely, the voltage is minimum (zero), current is maximum, and magnetic field is maximum. Therefore, at the center position of this YIG thin N' (15), the microstrip line (13) and Y I G WIifllP
(15), the sieve frequency coupling rate due to the magnetic field becomes maximum, and the degree of capacitive coupling due to the voltage between the input side microstrip line (13) and the connecting microstrip line (18) becomes minimum, and the Each time Regijin is collected.

Also, when a picture frequency signal with a wavelength different from λ is supplied to the input end microstrip line (13), the input end microstrip line (13), the Y I G Q crotch (15) and the connecting micro strip 1-Lip line (18
), both have a certain value of magnetic coupling and capacitive coupling, so no isolation is required.

If a bias DC magnetic field perpendicular to the thin film is applied to YIG thin film (15), ferrimagnetic resonance will occur at a certain frequency, and when this frequency is isolated, this frequency will be changed to the bandpass center frequency. A bandpass filter is obtained. The same can be said of the relationship between the microstrip line (1B), the Y I GB film (16), and the output microstrip line (14).

The frequency characteristics of the insertion loss and reflection loss of the filter of this example were as shown in FIG. In this case, the bandpass center frequency is 13,0 GHz, and the minimum ii 1 person m loss is 2
4 (dB, hti person loss of 3 dB4: f bandwidth is 2
5M Ilz.

The maximum return loss is 20 dB.

According to this magnetic resonance device X (filter), the number of dielectrics used is 1! By strengthening the coupling between the line and the ferromagnetic thin film without changing the dielectric constant, dielectric constant, or line arrangement, the insertion loss and its 3 dB bandwidth can be increased, and the passband center frequency can be increased by several dB. It is possible to achieve a surface frequency higher than Gllz, increase the degree of freedom, and facilitate manufacturing.

Incidentally, in the filters of Figs. 1 to 3, as shown in Fig. 5, the input and output side micros I-IJ tube line (13), <14) and the connecting microphone "J strip line (]8) are connected. All characteristic impedances are 50
For comparison, the frequency characteristics of insertion tm loss and reflection FLJ loss when Ω is constant are shown in FIG. In this case, the bandpass center frequency is 13.0 Glly+, the minimum insertion loss is 4 dB, the 3 dB bandwidth of the insertion loss is 10 MHz, and the maximum return loss is 13 dB, and the characteristics are inferior to those in FIG. 4.

I understand that

In addition, input and output side microstrip line <13)
, For the characteristic impedance (for example, 50Ω) of the input end and output end of (14), the input side microstrip life (13) (DY I C'n film (15) Tonneau coupling part or this and the output side microstrip line (
14) YIG Thin 1! ! The characteristic impedance of the coupling portion with (1[3) or (and) the connecting microstrip line (18) can be set low (for example, 20 to 25Q).

Further, the filter that can be used in the present invention is one-stage or multiple-stage filter with r+f function.

〔Effect of the invention〕

According to the present invention, the thickness of the dielectric used, the force of
Obtaining a ferromagnetic resonance device capable of increasing ζ, hli input FtJ loss and its 3 dB bandwidth by strengthening the coupling between the line and the ferromagnetic thin film without changing the rfL rate and line arrangement. be able to.

[Brief explanation of drawings]

FIG. 1 is a plan view of one embodiment of the present invention, and FIG. 2 is a plan view of the first and third embodiments of the present invention.
The figures are cross-sectional views on the ■-■ line and on the m-ni edge line, respectively.
Fig. 4 is a characteristic curve diagram of the embodiment, Fig. 5 is a top view of the reference example, Fig. 6 is a characteristic curve diagram of the reference example, Fig. 7 is a diagram of the conventional example, and Fig. 8 , 9, and 10 are cross-sectional views of each side of the magnetic device. (11) is treated as a dielectric material, and (12) is treated as a ground conductive j-1 (1
3) is the input microstrip line, (14) is the output microstrip line, and (15). (16) is YI G'Xl'XI, (17) is GGG, and (18) is a connecting microstrip line.

Claims (1)

[Claims] A ferromagnetic thin film to which a magnetic field is applied perpendicular to the film surface, and an input line coupled to the ferromagnetic thin film, the input line having a first characteristic impedance at its input end, and the ferromagnetic A ferromagnetic resonance device characterized by having a second characteristic impedance smaller than the first characteristic impedance at a coupling portion with the thin film.