JP3161227B2 - High frequency circuit element using resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency circuit device which is basically composed of a resonator, such as a filter or a duplexer, used in a high-frequency signal processing device such as a communication system.

[0002]

2. Description of the Related Art In a high-frequency communication system, a high-frequency circuit element basically composed of a resonator such as a filter or a duplexer is an essential element. Particularly, in a mobile communication system or the like, a narrow band filter is required for effective use of a frequency band. Further, in a mobile communication base station, a communication satellite, and the like, there is a strong demand for a filter capable of withstanding a narrow band, low loss, small size, and withstanding large power.

[0003] High-frequency circuit elements such as resonator filters currently used include those using a dielectric resonator,
Those using a transmission line structure, those using a surface acoustic wave element, and the like have become mainstream. Among them, the one using the transmission line structure is small and can be applied to high frequencies in the microwave and millimeter wave ranges, and is a two-dimensional structure formed on a substrate. It is widely used because it can be easily combined with. Conventionally, as this type of resonator, a half-wavelength resonator using a transmission line has been most commonly used.
By connecting a plurality of two-wavelength resonators, a high-frequency circuit element such as a filter is formed.

On the other hand, by using a superconductor having zero DC resistance as a conductor of a high-frequency circuit using a transmission line, reduction in loss of the high-frequency circuit and improvement of high-frequency characteristics have been attempted. In the case of conventional metal-based superconductors, a very low temperature environment of about 10K was required. However, the discovery of high-temperature oxide superconductors has made it possible to use superconductivity at relatively high temperatures (about 77K). Transmission line devices using these high-temperature superconducting materials have been studied.

[0005]

Generally, various characteristics of a superconductor change with temperature, and therefore, the characteristics of a device using a superconductor also change with temperature. This means
The same applies to a transmission line type high frequency circuit element using a superconductor. Although these characteristic instabilities with respect to temperature vary to some extent, they also exist in conventional devices using a metal conductor. In particular, when handling large power in a high-frequency circuit using a superconductor,
It has been found that local heat generation becomes remarkable, causing characteristic changes and, in extreme cases, element destruction.

In order to solve the above-mentioned problems of the prior art, the present invention relates to a high-frequency circuit element which can be applied particularly to high power.
It is an object of the present invention to provide an element configuration having a temperature control mechanism for stabilizing the characteristics.

[0007]

In order to solve the above-mentioned problems, a basic structure of a high-frequency circuit device according to the present invention is a non-degenerate orthogonal structure made of an electric conductor formed on a substrate. A resonator having two dipole modes as resonance modes, a temperature adjusting mechanism for heating or cooling the substrate itself, a thermal conductor for thermally coupling them, and measuring the temperature of each component. It is provided with a temperature measuring means. Here, the term “two non-degenerate orthogonal dipole modes” will be described. In a disc-type resonator, a resonance mode in which positive and negative charges are distributed one by one around the disk is called a dipole mode,
This definition can be applied to a planar resonator having an arbitrary shape. When considering a two-dimensional shape, this arbitrary dipole mode can be decomposed into two independent dipole modes whose current directions are orthogonal to each other. If the resonator shape is a perfect circle, it is said that the orthogonal modes have the same resonance frequency (the same energy) and are degenerate. Generally, in the case of a resonator having an arbitrary shape, the energy is not degenerated because the frequencies of these independent modes are different. Considering an elliptical resonator as an example, two independent orthogonal dipole modes are oriented in the major axis and minor axis directions of the ellipse, respectively, and the resonance frequency is determined by the lengths of major axis and minor axis, respectively. You. The non-degenerate orthogonal 2 described in this specification
One dipole mode refers to such a resonance mode in an elliptical resonator, for example. However, the resonator shape is not limited to an elliptical shape, and two dipole modes that are not degenerate and orthogonal to each other can be considered for a resonator having an arbitrary shape.

The present invention also provides various types of heat conductors or various types of heat conductors that are optimal for various applications in order to efficiently transmit the heat of the temperature adjusting mechanism to the resonator, or to efficiently remove the temperature of the resonator. Provides a heat exchange function that fits the body. Examples of the heat conductor include a solid having a high heat conductivity, a metal foil, at least one of Au, Ag, Pt, Pd, Cu, and Al, or a metal foil of an alloy of these materials and exhibiting electrical conductivity. It is a paste-like substance, gas or liquid, or helium gas.

Further, various temperature measuring methods are provided for efficiently performing temperature measurement and feeding back the result to a temperature controller. These are methods for measuring the change in resistance of a conductor or superconductor directly formed on a substrate as various temperature measurement means, and a method of contacting a substrate or a heat conductor and contacting each other. This is a method of measuring a thermoelectromotive force generated at a contact point of a thermocouple made of a different conductive material formed by the method described above.

[0010] The above-mentioned resonators have a transmission line type in mind in consideration of miniaturization. Therefore, the structure of the resonator is a microstrip line structure, a strip line structure, a coplanar waveguide structure, or the like.

[0011]

According to the structure of the high-frequency circuit element of the present invention,
The element characteristics can be stabilized by controlling the temperature by the temperature adjusting mechanism to keep the environmental temperature of the element constant. The cause stabilization is confirmed in the element characteristics can not leave the realm of estimation, believed order to REDUCE local heat generation by the temperature control, the stable operation of the high frequency device, locally controlled temperature control Seems to be effective.

When controlling the temperature, the temperature can be efficiently adjusted by using a material having a high thermal conductivity as the heat conductor. In addition, by providing a feedback circuit that measures the temperature of each component and controls the temperature of the temperature adjustment mechanism according to the result, it is possible to keep the temperature of the high-frequency circuit element constant following rapid temperature changes. I found it. This is effective in stabilizing the element characteristics to electrical noise or sudden thermal noise signals are both input. A structure using a superconductor as the material of the resonator is effective in reducing the loss of high-frequency characteristics. However, in order to stabilize the characteristics of the resonator, it is necessary to increase the temperature stability at low temperatures (fluctuations). Is important), and in this regard, the usefulness of the temperature adjustment mechanism, the temperature sensor, and the feedback circuit was remarkable.

Further, in order to efficiently transfer the heat of the temperature adjusting mechanism to the resonator or to remove the temperature of the resonator efficiently, if a solid having a high thermal conductivity is used as the heat conductor, it is efficient. In addition to controlling the temperature, the heat conductor itself can be used as a package for high-frequency circuit elements, and it has been found to be a practical configuration. In particular, brass casting, C
By processing a block of u, Al, etc. to form a package that covers the entire high-frequency circuit element, by contacting the temperature adjustment mechanism to keep the temperature constant, element characteristics can be stabilized and radiation loss of the high-frequency circuit element can be reduced. I found what I could do.
At this time, it has been found that coating the whole package with Au or an alloy containing Au is effective in reducing high-frequency loss. In particular, Cu, brass casting containing Cu, and the like have a large heat capacity in both thermal conductivity, suppress a temperature change to sudden thermal noise, and are inexpensive and easy to process, so that they are practical.

Further, a substrate on which a resonator is formed, a heat conductor,
Or metal foil between temperature control mechanisms, at least A
It has been found that, if a metal foil of one of u, Ag, Pt, Pd, Cu, and Al is used, or a metal foil of an alloy of these materials is interposed and a thermal conductor is used, the contact area increases and thermal bonding can be improved. Was. The metal foil also made good electrical contact with the electrical ground plane of the resonator structure, which was effective in stabilizing element characteristics. This is the same when a paste-like substance having electrical conductivity is used as a heat conductor, but in the case of an electrically conductive paste, the contact area is further increased and the heat conduction is improved by being better. . Also, the contact area was large and useful for making good electrical contact between the ground plane of the device (package) and the ground plane of the resonator. Furthermore, it has been found that the response during temperature control can be accelerated by conducting heat conduction by refluxing a gas or liquid. In particular, it has been found that a high-frequency circuit element using a superconductor requires cooling, but the use of helium gas enables good temperature control without liquefaction or solidification even at a low temperature. Since the high-frequency current flows on the surface of the resonator due to the skin effect, a large amount of heat is generated on the surface of the resonator. It has been found that effective temperature control is possible by spraying or refluxing helium gas or another fluid on the resonator surface.

On the other hand, various temperature sensors are brought into mechanical contact with a substrate or a heat conductor to measure the temperature, so that the temperature is measured efficiently and in a simple manner, and the result is fed back to the temperature controller. I found that I could do it. In particular, when a method of measuring a temperature by measuring a change in resistance value of a conductor or a superconductor directly in contact with a substrate and measuring the temperature is used, thermal contact with the substrate is good, and accuracy is high. I found that I could measure temperature. At this time, it has been found that a conductor on which a high-frequency circuit element is formed can be used as a resistor as it is, and that it can be formed simultaneously with patterning of the high-frequency circuit element, thereby providing a simple but highly accurate temperature measurement method. In addition, when a method of forming a thermocouple made of different conductive materials in contact with a substrate or a heat conductor and being formed in contact with each other and measuring a thermoelectromotive force generated at the contact is used, good thermal contact is obtained. And the fact that the thermocouple itself generates little heat does not affect the characteristics of the small high-frequency circuit element. In addition, this thermocouple structure allows conductors used for various ground planes to be used as one electrode,
It has also been found that it can be formed relatively easily.

Further, together with a temperature sensor on the same substrate,
When the temperature controller is formed directly and the substrate is made of a heat conductor, good temperature control is possible while the configuration is simple,
It was found to be practically effective.

Since the above resonators have a transmission line type in mind in consideration of miniaturization, the structure of the resonator is any one of a microstrip line structure, a strip line structure, and a coplanar waveguide structure. It is advantageous. In particular, the strip line provides a high-performance high-frequency circuit element because the radiation loss can be suppressed low. Further, the microstrip line type provides a practical high-frequency circuit element because only one substrate is required.

[0018]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

FIG. 1 is a conceptual diagram showing one embodiment of the invention according to the present invention. As shown in FIG. 1, in the present invention, a high-frequency circuit 1, a temperature controller 2 for adjusting the temperature of the high-frequency circuit,
The thermal conductor 3 is responsible for thermal coupling between the high-frequency circuit and the temperature controller. Further, in some cases, it is constituted by a temperature measuring means of each part and a feedback circuit 5 for feeding back the result to a temperature controller. An object of the present invention is to adjust or keep the temperature of a high-frequency circuit constant, and the structure of the high-frequency circuit, the operation type of the temperature controller, and the like may be any. On the other hand, the present invention clarifies the effectiveness when a superconductor is used in a high-frequency circuit. That is, when the superconductor is cooled to a certain temperature, the effect is more exhibited.

Embodiment 1 FIG. 2 is a sectional view of a high-frequency circuit and a heat conductor. The resonator 12 and the input / output terminals 13 are formed of a thin film of an electric conductor (for example, an Au thin film or a superconducting thin film) on a substrate 11, and a ground electrode 14 is provided on the back surface of the substrate 11. Further, a substrate having the ground electrode 14 provided on the substrate 11 and the rear surface was also arranged so as to face each other, and a transmission line type high frequency circuit having a strip line structure was obtained. This high-frequency circuit was installed in a package 21 made of Cu. This package is entirely plated with Au. This package 21 is installed in contact with the temperature controller, and serves as a heat conductor for thermally coupling the high-frequency circuit and the temperature controller. The above portions correspond to portions 1 and 3 in FIG.

(Embodiment 2) FIG. 3 shows a microstrip line structure which does not use a substrate opposed to FIG. The ground plane 14 is adhered to the package 21 by the conductive paste 26. Package 21 is also C
The heat conductor is made of u and is in contact with the temperature controller. Also,
A gas or liquid that is refluxed or convected is injected into the space inside the package to form another heat conductor. This configuration was effective when the superconductor was used as a resonator. That is, although it is necessary to cool the resonator in order to obtain a superconducting state, an Au-plated Cu package serving as a heat sink having a large heat capacity was brought into contact with the cooler. When operating near the temperature of liquid helium, the cooled helium gas is returned to the substrate surface (resonator surface) to perform stable temperature control and quick temperature control. When using at the temperature of liquid nitrogen, an inert gas such as helium gas or argon gas cooled to the temperature of liquid nitrogen, liquid nitrogen itself, or a freon-based organic solvent that does not solidify at the temperature of liquid nitrogen is applied to the substrate surface. Refluxed.

(Embodiment 3) FIG. 4 is a cross-sectional view when a heat conductor is a metal foil or a paste-like substance. Increasing the contact area between the substrate 11 on which the high-frequency circuit element 12 is formed and the thermal conductor 2 by inserting a metal foil or a paste-like substance between the ground plane 14 and the temperature controller 2 as the thermal conductor 3 And efficient temperature control was possible. Further, in the case of the figure, a microstrip line type high-frequency circuit having a ground plane 14 provided on the back surface of the substrate is described. However, together with the ground plane 14, the surface of the temperature controller 2, the metal foil as the heat conductor 3, Alternatively, by using a paste-like substance as a good electric conductor, the ambient potential and the ground potential can be easily made the same, which is practically effective.

(Embodiment 4) FIG. 5 shows a microstrip line structure which does not use a substrate facing a strip line type high frequency circuit element, and has a sensor for measuring the temperature of the high frequency circuit element (plan view). ). The resonator has an elliptical shape, and the temperature sensor is a thin-film resistor 15 formed on a substrate on which the resonator has been formed. The temperature is determined from the change in the resistance value of the resistor 15. The result of the temperature measurement is monitored externally, and in some cases, the output of the temperature regulator is controlled by a feedback circuit. The resistor 15 may be formed on a substrate such as a Pt thin film sensor, a carbon thin film sensor, or an oxide thin film. Needless to say, the high-frequency circuit may be of a stripline type or a coplanar type.

(Embodiment 5) FIG. 6 shows another embodiment of a method for measuring the temperature of a high-frequency circuit element. High frequency circuit element 12
A ground plane 14 is provided on the back surface of the substrate 11, and the ground plane is used as one electrode of a thermocouple, and another material is brought into contact therewith. The structure is such that the temperature of the high-frequency circuit element 12 is measured by the electromotive force of the thermocouple 16. Normally, the ground plane 14 uses a material having good electric conductivity, for example, Au, Cu, a superconductor, or the like. A thermocouple can be easily formed by contacting a different conductive material in contact with these materials. In general, a thermocouple used at a low temperature is an AuFe-chromel thermocouple. However, an AuFe alloy was used for a part of the ground plane, and the temperature could be easily measured only by contacting a chromel electrode. Even if a thermocouple is similarly formed on the heat conductor to control the temperature of the heat conductor, the temperature of the high-frequency circuit element can be similarly controlled.

(Specific Examples) In order to better understand the present invention, specific examples will be described. FIG. 7 shows the configuration of the high-frequency circuit device manufactured in this example. The resonator 12 is an elliptical conductor plate, the diameter is about 7 mm, and the gap between the long axis / short axis ratio and the input / output coupling is set so that the bandwidth is about 2%. First, a high-temperature oxide superconductor having a thickness of 1 μm was formed on both surfaces of a substrate 11 made of lanthanum alumina single crystal. The high-temperature oxide superconductor is generally referred to as an Hg-based superconductor, and is mainly composed of HgBa ₂ CuO _x
A thin film called (1201 phase) was used. This thin film is 9
A superconducting transition occurred at 0K or higher. Thereafter, an Au thin film having a thickness of 1 μm is formed on one side by a vacuum deposition method, and the superconductor and the Au thin film are formed.
The ground plane 14 was made of a thin film. The elliptical conductor was then patterned in a superconducting thin film on the surface opposite the ground plane by photolithography and argon ion beam etching techniques. A on the surface of Cu package 21
u, and a substrate 11 having a resonator formed therein is installed thereon. Further, a superconducting thin film (1201 phase H
gBa ₂ CuO _x ) and a substrate on which an Au thin film is formed.
A high frequency circuit element composed of a strip line type resonator was constructed. Although there are some gaps in the figure, the substrates are actually overlapped. Package 21 and installation surface 14
The space is adhered with a conductive paste 26 (in this case, Ag paste is used) to ensure thermal conductivity and electrical grounding. Further, an AuFe-chromel thermocouple was brought into contact with the package 21 to measure the thermoelectromotive force and monitor the temperature. The entire package was cooled by a refrigerator capable of electrically controlling a small output, and a control signal corresponding to the thermoelectromotive force was fed back to the refrigerator to adjust the temperature. With respect to the input power dependence of the insertion loss in the case of this high-frequency circuit element, it was confirmed that the insertion loss did not change even at a power of 32.1 dBm (1 W or more). It was also confirmed that the characteristics of the high-frequency circuit element could be adjusted by slightly adjusting the relative position of the opposing substrates.

[0026]

The characteristics of a high-frequency device, particularly a device using a superconductor, change due to temperature fluctuations. When a large amount of power is applied, heat is generated due to high-frequency loss, and the temperature rises. These problems become remarkable when handling a signal with a large power and become a problem. However, as described in this specification, the high-frequency circuit element of the present invention includes a temperature control mechanism and has a function of keeping the temperature constant,
There is an effect of suppressing this characteristic change (fluctuation). This exhibited a remarkable effect in a high-frequency device using a superconductor.
In addition, the use of a good heat conductor has the effect of increasing the temperature controllability. Especially when using conductive paste,
It also has the function of taking the ground plane potential simultaneously with the function of the heat conductor,
High practical effect. Further, the use of a thin-film temperature sensor is advantageous for integration on the substrate on which the resonator is manufactured, and has the effect of increasing the temperature measurement accuracy. In addition, the thermocouple-type temperature measuring means hardly generates heat at the time of measurement, can be easily formed, and has a high practical effect.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a temperature-controlled high-frequency circuit element according to the present invention.

FIG. 2 is a cross-sectional view of a strip line type high frequency circuit device according to a first embodiment of the present invention.

FIG. 3 is a sectional view of a microstrip line type high-frequency circuit device according to a second embodiment of the present invention;

FIG. 4 is a sectional view showing a microstrip line type high-frequency circuit device according to a third embodiment of the present invention.

FIG. 5 is a plan view showing an example of a temperature monitoring method according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view showing another example of the temperature monitoring method in the fifth embodiment according to the present invention.

FIG. 7 is a sectional view showing a specific example of the high-frequency circuit element according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High frequency circuit element 2 Temperature controller 3 Thermal conductor 4 Temperature measuring means 5 Feedback circuit 11 Substrate 12 Resonator 13 Input / output terminal 14 Ground plane 15 Resistor 16 Thermocouple 21 Package 26 Conductive paste

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kentaro Seto 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (US, A) US Patent 3,796,970 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01P 7/08 ZAA G05D 23/19 H01P 1/208 ZAA

Claims (3)

(57) [Claims] 1. A temperature measuring means, a temperature adjusting mechanism, a resonator having two non-degenerate orthogonal dipole modes as resonance modes formed of an electric conductor formed on a substrate, and the temperature adjusting mechanism. And a thermal conductor that thermally couples the substrate or the electrical conductor to the components , and the thermal conductor is a metal foil, an electrical conductor.
A high-frequency circuit element, which is a paste, a liquid, or a gas . 2. The metal foil serving as a heat conductor includes at least one of Au, Ag, Pt, Pd, Cu, and Al, or is made of an alloy of these materials. 2. The high-frequency circuit element according to 1 . 3. A high-frequency circuit device according to claim 1, wherein the thermal conductor is characterized in that it is a helium gas.