RU66612U1 - MICROWAVE ELEMENT ON EPITAXIAL STRUCTURE - Google Patents

Abstract

The claimed utility model “Microwave Element on Enitaxial Structure” relates to the field of microwave technology and can be used to create spin-wave devices (devices on magnetostatic spin waves - MSW): delay lines, resonator filters, limiters of small and large power levels and other devices carrying out information processing in the microwave range using thin magnetic films.

The microwave element contains a substrate, on one side of which a yttrium ferrogranate (YIG) film is applied and converters, and differs in that the YIG film is made with a thickness reduced along its edges, and the substrate itself is made of ceramic microwave material, the temperature coefficient of expansion of which must lie within 0.98 TCR _firing <TCR _n <1.02 TCR _firing , where TCR _firing is the coefficient of linear expansion of the YIG film material, and TCR _n is the same for the ceramic substrate.

Due to the simplicity and low cost of the device, the element can find application in mobile communications, digital television and other areas of microwave technology.

Description

The inventive utility model relates to the field of microwave technology and can be used to create spin-wave devices (devices on magpitostatic spin waves - MSW): delay lines, filters and resonators, power level limiters and other devices that implement the processing of microwave information using thin magnetic films, for example, films of iron-yttrium ferrogranate (YIG).

The main requirements that apply to the elements under consideration are the performance of a single-mode operation mode, the simplicity of providing a single-mode operation, and the stability of parameters when changing external influences.

A device is known on the MSV (autos Certificate No. 1737702) used in devices for delaying and processing signals on a microwave in single crystal ferromagnetic epitaxial YIG films.

The device comprises a gallium-gadolinium garnet substrate, a YIG film and converters and absorbers placed on its surface.

This device has two drawbacks that limit its practical application.

The first - thermal stabilization of the device is not provided.

The second is the difficulty of obtaining a single-mode propagation regime for MSWs. Because of the technology for producing absorbers, as it requires a strictly controlled mode of diffusion doping of the YIG film, which in turn leads to a small percentage of suitable products.

In the copyright certificate No. 1688319 “Microwave - an element on an epitaxial ferrite structure” it is proposed to eliminate one of the above disadvantages - the absence

thermal stability by thermobimetallic plate on the other side of a single-crystal gallium-gadolinium substrate.

However, the introduction of such a plate not only complicates the design, but, most importantly, violates the condition for a single-mode operation, which changes due to changes in the waveguide structure of the element.

The closest analogue is the invention "Thermostable liner on an epitaxial ferrite structure for microwave devices" (certificate of autopsy No. 1762350), which we took as a prototype.

In the device, a YIG film is placed on the surface of a dielectric substrate of gallium-gadolinium garnet, on the opposite side of which a plate of dielectric material - quartz glass is rigidly fixed - the temperature coefficient of which is less than the temperature coefficient of expansion of the substrate.

This device is much simpler than the previous analogue and allows you to get closer to single-mode mode during the propagation of MSW.

The disadvantages of this device are: the presence of an adhesive layer between a single crystal substrate and a dielectric quartz plate and their predetermined flat thickness. Both of these factors together lead to the fact that it is impossible to provide the necessary and sufficient value of thermal compaction in advance, and the adhesive technology does not allow achieving the required repeatability of thermal stabilization from sample to sample.

The purpose of the claimed utility model is to simplify the design of the microwave element on the epitaxial structure while reducing its cost and, as a result, increasing the field of application of the element.

This goal is achieved by the fact that the epitaxial film of yttrium ferrogranate deposited on a substrate is made with a decrease in the thickness of the film along its edges, and the substrate itself is made of ceramic microwave material, the temperature coefficient

the expansion of which should lie within the limits of 0.98 TCR _firing <TCR _n <1,02 TCR _firing , where the GCR _firing is the coefficient of linear expansion of the YIG film material, and TKP _n is the same for the ceramic substrate.

The proposed model is illustrated by:

Figure 1, which shows the design of the proposed microwave element;

Figure 2, which illustrates the effect of the formation of a single-mode mode of operation of the element;

Figure 3, which illustrates the effect of temperature stabilization.

In the proposed device (Figure 1) depicted

1) - YIG film

2) - A section of a film with a reduced thickness

3) - The electromagnetic wave converter in the MSW

4) - Substrate made of ceramic microwave material

5) - Metal grounding surface

6) - The direction of the magnetizing field H

7) - A section of a film with a reduced thickness

8) - MSV to electromagnetic wave converter

In the process of manufacturing a microwave element, the substrate (4) was selected from a ceramic microwave material, for example, corundum with or without additives, 0.5 mm thick and the choice of other sizes depending on the application in specific MSW devices; the temperature coefficient of expansion of the substrate should lie within 0.98 TCR _firing <TKR _n <1.02 TKR _firing .

Sections (2) and (7) with a reduced thickness of the YIG film are formed during epitaxy in a single technological process.

The device operates as follows.

The transducer (3) excites a magnetostatic wave - MSW in the YIG film (1), the MSW propagates in the film (1), and in the transducer (8) the MSW excites an electromagnetic wave for all subsequent processing.

In the YIG film (1), in a single technological cycle, sections of the film (2) and (7) are formed with a reduced thickness compared to the film (1).

Sections (2) and (7) have dispersion dependences that differ from the rest of the film (1). As a result of this, the MSW attenuates the inhomogeneous types of waves, and the main wave acquires a single-mode propagation mode while increasing the spectral range. As the temperature in the YIG film changes, the effective anisotropy fields change; at the same time, because the temperature coefficients of the substrate and the YIG film are different, changes in the elastic deformations of the substrate compensate for the effective anisotropy fields of the YIG film and lead to stabilization of temperature changes (for example, the frequency drift of the element).

Figure 2 illustrates the effect of the formation of a single-mode mode of operation of the element.

Where (a) is a single-mode mode, the characteristic has a smooth frequency dependence;

(b) - multimode mode, the characteristic has a rugged frequency dependence due to other modes;

Figure 3 illustrates the effect of temperature stabilization, where

(1) - the temperature dependence of the frequency drift with thermal compensation when using ceramic microwave material with the characteristics of the "temperature coefficient of expansion of the TCR, corresponding to the above state, as a substrate;

(2) - frequency drift without thermal compensation.

The technical result in the implementation of the proposed utility model is:

1. In ensuring regulated and predetermined thermal stabilization due to the choice of limits for TCR. The experimental data (Table 1) are given for an extended range of TCR values within the selected limits. The criterion is the change in the frequency of the device ΔF (figure 2), while the allowable value of ΔF should not exceed the value of the bandwidth, in our case 10 MHz. The initial value of the TCR of the film is taken equal to α = 12 * 10 ^-6 1 / deg.

Table 1 TCR relates. 0.96 0.97 0.98 0.99 one 1.01 1,02 1,03 ΔF, MHz 19 eleven 5 2 0 four 8 13

2. With the exception of a single-crystal material from gallium-gadolinium garnet as a substrate for a cheap (an order of magnitude) polycrystalline ceramic microwave; material with a wide and variable range of TCR;

3. In the application of a simple technology for epitaxy of YIG film with a reduced film thickness at the edges;

4. In the creation of a microwave element for devices on the MSW, which has wide functional capabilities due to the implementation of a single-mode (significantly reducing interference) mode and thermostable operation of the device while simplifying and cheapening its design.

5. These circumstances expand the scope of application of the microwave element in devices of widespread use (for example, cellular communications, digital television and other areas of microwave technology).

Claims (1)

A microwave element on an epitaxial structure, containing a substrate on one side of which a film of yttrium iron garnet (YIG) is deposited and converters, characterized in that the YIG film is made with a reduced thickness along its edges, and the substrate itself is made of ceramic microwave material, the temperature coefficient of which must lie to the range of 0.98 TCR _jig <TCR _n <1,02 TCR _jig , where TCR _jig is the temperature coefficient of expansion of the YIG material, and TKRp is the temperature coefficient of expansion of the substrate material.