JP2021010091A - Transmission circuit integrated microwave generation element - Google Patents

Abstract

To provide a transmission circuit integrated microwave generation element that can increase the output of microwaves without using an amplifier.SOLUTION: A transmission circuit integrated microwave generation element includes a ferromagnetic multilayer magnetoresistive sensor, and a lower stripline and an upper stripline for transmitting microwaves oscillated from the ferromagnetic multilayer magnetoresistive element, and the output impedance of the ferromagnetic multilayer magnetic resistance element is 500 Ω or more, and the impedances in the lower and upper strip lines are converted such that the output impedance of the transmission circuit integrated microwave generation element is 15% or less of the output impedance of the ferromagnetic multilayer magnetoresistive sensor, and the microwave oscillated from the ferromagnetic multilayer magnetic resistance element is transmitted by using the lower and upper strip lines.SELECTED DRAWING: None

Description

The present invention relates to a transmission circuit integrated microwave generator.

Electronic elements such as mobile phones and tablets are driven by a battery that is a DC power source, but an internal oscillator generates high-frequency electromagnetic waves of around 100 MHz to 200 GHz to perform high-speed wireless communication and the like. Communication technology using such high-frequency electromagnetic waves is particularly important in order to cope with the explosive increase in the amount of communication information accompanying the socialization of IoT (Internet of Things). As the speed of communication increases, miniaturization and high efficiency of oscillators for high-frequency electromagnetic waves have become important issues.

In recent years, as an oscillator for such high-frequency electromagnetic waves, a spin torque oscillator (STO: spin torque oscillator) has attracted attention because it can oscillate microwaves and is easily miniaturized. The spin torque oscillator is a microwave oscillating element that uses a magnetoresistive element (so-called MR element) as an oscillation source, and has a three-layer structure in which a magnetization free layer / spacer layer / magnetization fixed layer are laminated in this order as a basic structure. Then, when a DC current I is passed from the magnetized free layer of the magnetic resistance element to the magnetized fixed phase by a power source, the magnetization of the magnetized free layer exerts a spin torque from electrons whose spins are polarized by the magnetized fixed layer and the insulating layer. In response, it vibrates at the Lamore frequency (GHz band) of the magnetization free layer, and the angle θ formed by the magnetization of the magnetization free layer and the magnetization of the magnetization fixed layer changes with time. The spin valve magnetoresistive effect determined by such an angle θ changes with time, and the AC component of the voltage appears as a signal in the GHz band, so that microwaves appear.

Examples of the microwave generating element using such a magnetic resistance element include a ferromagnetic multilayer magnetic resistance element and the ferromagnetic multilayer magnetic resistance element in Japanese Patent Application Laid-Open No. 2006-295908 (Patent Document 1). A transmission circuit-integrated microwave generating element including a lower strip line and an upper strip line provided so as to sandwich the microwave is disclosed. However, the conventional microwave generation element integrated with a transmission circuit as described in Patent Document 1 has not yet been sufficient in terms of increasing the output of microwaves.

Japanese Unexamined Patent Publication No. 2006-295908

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a transmission circuit-integrated microwave generator capable of increasing the output of microwaves without using an amplifier. With the goal.

In order to achieve the above object, the present inventors first repeatedly studied conventional microwave generating elements, and obtained the following findings. That is, first, in general, in a ferromagnetic multilayer magnetoresistive sensor, in order to generate microwave oscillation due to spin torque, the magnitude of the DC current I depends on the structure of the ferromagnetic multilayer film and the surrounding magnetic field environment. The value must be equal to or greater than the threshold current Ic determined. Here, since the oscillation output P from the ferromagnetic multilayer film magnetoresistive element is proportional to the DC current I, the square value of the magnetic resistance ratio, the element resistance, etc., as the DC current I increases. Therefore, the oscillation output P becomes large (see equation (1) described later).

However, when using a ferromagnetic multilayer magnetoresistive element, if the element applied voltage V is actually increased in order to increase the DC current I, a spacer layer (for example, a spacer layer using MgO) is used. Therefore, it is necessary to limit the magnitude of the element applied voltage V to a range in which dielectric breakdown does not occur. Therefore, when a ferromagnetic multilayer magnetoresistive element is used, it is considered necessary to increase the output while suppressing dielectric breakdown of the spacer layer.

Here, as a method for increasing the output while suppressing such dielectric breakdown, for example, the film thickness of the spacer layer is increased to cause crystal defects in the spacer layer (insulating layer) and the insulating layer. It is conceivable to take a distance between the surface and the interface of the ferromagnetic layer. However, when the film thickness of the spacer layer is increased, the output impedance of the ferromagnetic multilayer magnetoresistive element increases exponentially with respect to the film thickness, and the impedance mismatch with the load side increases. Therefore, if the film thickness is simply increased, the transmission efficiency is rather lowered, and there arises a problem that the desired oscillation output cannot be obtained. Further, when the impedance mismatch with the load side is increased in this way and the temperature rises due to the power loss caused by the impedance mismatch (when heat is generated), the crystal magnetism of the magnetization free layer in the element is generated. Since the anisotropy is lowered, it is considered that there is a problem that the Larmor frequency (the oscillation frequency of the element) is lowered.

On the other hand, when driving a ferromagnetic multilayer magnetoresistive sensor at a low voltage that does not cause dielectric breakdown, the micro is emitted from the device by connecting to an amplifier in the microwave transmission line and amplifying the output with the subsequent amplifier. It is also possible to increase the output of the waves. However, since microwave amplifiers are usually large in length and width of about several tens of mm, small-sized ferromagnetic multilayer magnetoresistive elements are used when used in communication equipment and the like. However, there arises a problem that such equipment cannot be miniaturized. In this way, from the viewpoint of downsizing communication equipment, etc., the emergence of technology that can increase the output of microwaves without using an amplifier while using a ferromagnetic multilayer magnetoresistive element. Is desired.

In view of the problems of the prior art, the present inventors have conducted diligent research to achieve the above object, and as a result, the transmission circuit-integrated microwave generating element has been referred to as a ferromagnetic multilayer film magnetic resistance element. A lower strip line and an upper strip line for transmitting microwaves oscillated from the ferromagnetic multilayer magnetic resistance element are provided, and the output impedance of the ferromagnetic multilayer magnetic resistance element is set to 500Ω or more. In the lower part and the upper stripline, the output impedance of the microwave generation element integrated with the transmission circuit (the impedance of the microwave output side (load side) of the transmission circuit including the lower part and the upper stripline) is the said. By converting the impedance so that it becomes 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element, the microwave oscillated from the ferromagnetic multilayer magnetic resistance element is used in the lower and upper strip lines. As a result, it has been found that efficient transmission (propagation) is possible, and it is possible to increase the output of microwaves without using an amplifier, and the present invention has been completed.

That is, the transmission circuit-integrated microwave generating element of the present invention includes a ferromagnetic multilayer magnetoresistive element and a lower stripline and an upper stripline for transmitting microwaves oscillated from the ferromagnetic multilayer magnetoresistive element. It is a transmission circuit integrated microwave generator equipped with
The output impedance of the ferromagnetic multilayer magnetoresistive element is 500Ω or more, and
In the lower part and the upper strip line, impedance conversion is performed so that the output impedance of the microwave generation element integrated with the transmission circuit becomes 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element, and the strength is changed. It is characterized in that microwaves oscillated from a magnetic multilayer film magnetic resistance element are transmitted by using the lower portion and the upper strip line.

As described above, in the transmission circuit integrated microwave generating element of the present invention, the output impedance of the transmission circuit integrated microwave generating element (in the transmission circuit integrated microwave generating element) in the lower part and the upper strip line. Impedance on the load side when viewed from the ferromagnetic multilayer magnetic resistance element: Impedance on the output side of microwaves in the lower strip line and upper strip line) is the output impedance (500Ω or more) of the ferromagnetic multilayer magnetic resistance element. ) Is subjected to impedance conversion so that the impedance is 15% or less (Note that the ratio of the converted impedance (15% or less) to the output impedance of the ferromagnetic multilayer magnetic resistance element in such impedance conversion is determined. , Hereinafter, in some cases, simply referred to as "impedance conversion ratio"). Here, the configuration in which an element having an output impedance of 500 Ω or more is used as the ferromagnetic multilayer magnetic resistance element and the impedance on the load side is 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element is described above. Since it is clear that impedance mismatch (mismatch) occurs between the output of the ferromagnetic multilayer magnetic resistance element and the load connected to it, it cannot be recalled that it is actually designed and used based on the prior art. Further, even if a ferromagnetic multilayer magnetic resistance element having an output impedance of 500 Ω or more is simply used for a conventional transmission circuit, the impedance of a known external antenna is generally about 50 Ω or 75 Ω, so that the load side Due to the impedance mismatch with (for example, an external antenna), it is difficult to increase the output of microwaves. On the other hand, in the present invention, from the viewpoint of increasing the output of microwaves, in order to utilize a ferromagnetic multilayer magnetoresistive element having an output impedance of 500 Ω or more, the said in the lower part and the upper stripline. The impedance conversion ratio is set to 15% or less (note that such an impedance conversion ratio is more preferably 10% or less, further preferably 5% or less). Considering that the lower limit of the impedance conversion ratio is limited to the range in which the spacer layer of the ferromagnetic multilayer magnetoresistive sensor can be tunneled, the lower limit of the impedance conversion ratio of the ferromagnetic multilayer magnetoresistive sensor Although it can be appropriately changed according to the magnitude of the output impedance, it is conceivable to set it to about 0.001%, for example. Then, by performing impedance conversion in the lower portion and the upper strip line at the impedance conversion ratio as described above, a ferromagnetic multilayer film magnetic resistance element having an output impedance of 500 Ω or more (for example, several kΩ) was used. In this case, even when a known external antenna (general antenna or the like) having an impedance of about 50Ω or 75Ω is connected to the microwave generation element integrated with the transmission circuit, the generation of reflected waves is sufficiently suppressed. At the same time, it becomes possible to more efficiently transmit (propagate) the microwave oscillated from the ferromagnetic multilayer magnetic resistance element by using the lower portion and the upper strip line.

Further, in the transmission circuit integrated microwave generating element of the present invention, the output impedance of the ferromagnetic multilayer magnetoresistive element is 500Ω or more (more preferably 800Ω or more, still more preferably 1000Ω or more) from the viewpoint of increasing the output. (50 kΩ or less) is used. Regarding such a ferromagnetic multilayer magnetic resistance element, it is generally necessary to pass a current of several mA in order to obtain the current density required for driving the ferromagnetic multilayer magnetic resistance element. In addition, since the magnitude of the voltage used to drive the ferromagnetic multilayer magnetic resistance element is about 5V or less, the output is also taken into consideration from the viewpoint of achieving sufficiently high output even under such conditions. An element having an impedance of 500Ω or more (for example, an element having an output impedance of several kΩ) is used.

On the other hand, in Patent Document 1, it is preferable that the desired range of the resistance value of the magnetoresistive element is 1Ω to 1kΩ, and that the resistance value of the element is 1Ω or more and 10kΩ or less in terms of the DC resistance value. It is stated to that effect. However, regarding the resistance value of such a magnetoresistive sensor, paragraph [0021] of the same document states, "In order to minimize the loss due to the impedance mismatch at the junction between the magnetoresistive sensor and the microwave transmission circuit, the magnetoresistive sensor. It is desirable to match the resistance value of the element with the impedance value of the microwave transmission circuit. " As described above, in Patent Document 1, the technique of matching the resistance value of the magnetoresistive element with the impedance value of the microwave transmission circuit is merely specified, and the magnetoresistive element having an output impedance of 500Ω or more is defined. From the viewpoint of impedance matching when used, the technical idea of converting impedance so that the impedance conversion ratio is 15% or less in the transmission circuit (lower strip line and upper strip line) is disclosed. Not.

As described above, in the transmission circuit integrated microwave generating element of the present invention, while the output impedance of the ferromagnetic multilayer film magnetic resistance element is 500Ω or more, the lower part and the upper part have the above impedance conversion ratio. Since impedance conversion is performed using the strip line, the lower and upper strip lines match the impedance between the output impedance of the microwave generator with integrated transmission circuit and the impedance on the load side (external antenna, etc.). This makes it possible to efficiently transmit (propagate) microwaves to the load side via the lower part and the upper strip line, and oscillates (outputs) microwaves to the outside with high output. It is possible to do. In the present invention, since impedance conversion is performed using the lower portion and the upper strip line at the impedance conversion ratio as described above, the impedance is oscillated from a ferromagnetic multilayer film magnetic resistance element having an output impedance of 500 Ω or more. High-power microwaves are transmitted to the load side via the lower and upper strip lines at a ratio such that the transmission efficiency is 40% or more (more preferably 60% or more, further preferably 80% or more). (Propagation) is also possible (Note that the transmission efficiency referred to here can be measured using a vector network analyzer (commonly known as "VNA": for example, a trade name "E5071C" manufactured by Keyence) as a measuring device). Among the S-parameters, the value obtained by squaring the peak value of S21 using the value of S21 (formula: [transmission efficiency] = (S21 peak) ² is calculated) is adopted). ..

As described above, in the present invention, while using an element having an output impedance of 500Ω or more as the ferromagnetic multilayer film magnetic resistance element, the transmission circuit (the lower part and the upper strip) is used according to the magnitude of the impedance on the load side. In the line), impedance conversion is performed at the ratio as described above to match the output impedance and the load impedance. Therefore, according to the present invention, it is not necessary to use a separate amplifier to increase the output, and a ferromagnetic multilayer magnetic resistance element (element having an output impedance of 500Ω or more) having a sufficiently high output impedance is used for microwaves. Since it is possible to increase the output of the wave, it is possible to efficiently increase the output of the microwave and reduce the size of the oscillating device incorporating the microwave generation element integrated with the transmission circuit. Therefore, for example, when the transmission circuit integrated microwave generator of the present invention is used for a communication device or the like, it is possible to increase the output of the microwave while reducing the size of the communication device and perform communication. It is useful for speeding up and downsizing. In the present invention, the "microwave" means an electromagnetic wave having a frequency of 300 MHz to 300 GHz.

Further, in such a transmission circuit integrated microwave generating element of the present invention, at least one of the lower portion and the upper strip line has a microwave frequency output from the ferromagnetic multilayer magnetic resistance element. On the other hand, it is more preferable that the anti-resonant first transmission line and the resonating second transmission line are combined so as to magnetically resonate with respect to the frequency of the microwave. In this way, the first transmission line that is anti-resonant with respect to the frequency of the microwave output from the ferromagnetic multilayer magnetic resistance element and the second transmission line that resonates with respect to the microwave of the predetermined frequency are provided. By combining and performing power transmission by magnetic resonance, the first transmission line and the second transmission line are used like resonators (the first transmission line is a parallel resonator (first resonator), the second is a second. The transmission line can be used as a series resonator (second resonator) to enable transmission of AC signals, and the constituent requirements of the resonator, specifically parallel resonance, series resonance, and their constituents. It is possible to convert the impedance according to the ratio of the resonance to the capacitance. Therefore, high-output microwaves can be extracted more efficiently without using a resonator (impedance converter) or an amplifier separately. In the conventional microwave generation element integrated with a transmission circuit, the output signal to be taken out is a superposition of an AC component and a DC component, whereas as described above, the microwave is generated by using magnetic resonance. When outputting, since the first transmission line and the second transmission line are not directly electrically connected, it is possible to extract and output only the AC component, and in this respect as well, microwaves can be output more efficiently. It can be taken out. Further, the "frequency of the microwave output from the ferromagnetic multilayer magnetic resistance element" relating to the anti-resonance and resonance of the first transmission line and the second transmission line is the microwave generation element integrated with the transmission circuit of the present invention. It is the frequency of the microwave intended to be output to the outside by (the Ramore frequency of the magnetization free layer (the oscillation frequency of the element) of the ferromagnetic multilayer magnetic resistance element, and the ferromagnetic multilayer magnetism depending on the purpose. The desired frequency can be obtained by changing the design of the resistance element and the external magnetic field). Here, it is considered that the microwave output from the ferromagnetic multilayer magnetic resistance element has a small proportion of frequency components different from the basically target oscillation frequency (Lamore frequency of the free-magnetized layer) due to its design. Therefore, the frequency with the highest intensity in the frequency band of the microwave oscillated from the ferromagnetic multilayer magnetic resistance element is determined as "the frequency of the microwave output from the ferromagnetic multilayer magnetic resistance element". May be good.

Further, in the transmission circuit integrated microwave generation element of the present invention, as described above, at least one of the lower portion and the upper strip line is a first transmission line that is anti-resonant with respect to the microwave frequency. In the case where the second transmission line that resonates with respect to the frequency of the microwave is used in combination so as to magnetically resonate, for example, between the first transmission line and the second transmission line. By adjusting the distance, the impedance conversion ratio can be changed. Therefore, when the first transmission line and the second transmission line are used as described above, for example, the design of the distance between the first transmission line and the second transmission line may be appropriately changed. This makes it possible to match the output impedance of the ferromagnetic multilayer magnetoresistive element with the impedance on the load side.

According to the present invention, it is possible to provide a microwave generation element integrated with a transmission circuit capable of increasing the output of microwaves without using an amplifier.

It is a schematic top view which shows typically one preferable embodiment of the transmission circuit integrated microwave generation element of this invention from the top surface side. It is sectional drawing which shows typically the AA'cross section of the transmission circuit integrated microwave generation element of the embodiment shown in FIG. It is sectional drawing which shows typically the BB'cross section of the microwave generation element integrated with the transmission circuit of embodiment shown in FIG. It is sectional drawing which shows typically the CC'cross section of the transmission circuit integrated microwave generation element of the embodiment shown in FIG. It is an enlarged perspective view which shows typically the ferromagnetic multilayer film magnetoresistive element shown in FIG. FIG. 5 is a top view schematically showing an enlarged portion of only a portion of a first transmission line and a second transmission line included in the transmission circuit integrated microwave generator of the embodiment shown in FIG. 1. It is a schematic diagram of a preferred embodiment of a microwave oscillator including the transmission circuit integrated microwave generator of the embodiment shown in FIG. 1. It is a drawing which shows one preferable embodiment of the flowchart of the design of a transmission line (strip line). FIG. 6 is a schematic diagram schematically showing the relationship between the first transmission line and the second transmission line in a preferred embodiment of the upper stripline (an embodiment having a linear first transmission line and a linear second transmission line). is there. It is a schematic diagram which shows typically the relationship between the 1st transmission line and the 2nd transmission line in the preferable embodiment of the upper strip line (the embodiment of the configuration in which the 2nd transmission line is parallelized). A model schematically showing the relationship between the first transmission line and the second transmission line in a preferred embodiment of the upper strip line (an embodiment in which the first transmission line and the second transmission line are each formed into a polygonal line shape). It is a figure. It is a schematic diagram schematically showing a preferable embodiment of a transmission line having the same shape as the upper strip line and the lower strip line. It is a schematic diagram conceptually showing the relationship between the upper strip line and the lower strip line in a preferred embodiment of a transmission line having a partially short-circuited configuration. It is a top view which shows typically the upper strip line of the measurement sample (however, excluding measurement samples (A) and (B)) used in various measurements performed in Example 1. FIG. 6 is a graph showing the relationship between the distance (gap) between the first transmission line and the second transmission line when the output impedance is 50Ω, and the input impedance [unit: Ω], which was measured in the first embodiment. 6 is a graph showing the relationship between the line widths of the first transmission line and the second transmission line when the output impedance is 50Ω and the input impedance [unit: Ω] measured in the first embodiment. It is a top view which shows typically the upper strip line of the measurement sample (A). It is a top view which shows typically the upper strip line of the measurement sample (B). It is a graph which shows the relationship between the frequency of the microwave used for measurement, the impedance of the measurement sample (A), and the impedance of the measurement sample (B). It is a graph which shows the relationship between the frequency of the microwave input to the element (measurement sample (X) and (Y)) at the time of measurement, and the transmission efficiency of each measurement sample.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description and drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a schematic top view schematically showing a preferred embodiment of the transmission circuit integrated microwave generator of the present invention from the top side. FIG. 2 is a cross-sectional view schematically showing an AA'cross section of the transmission circuit integrated microwave generator of the embodiment shown in FIG. Further, FIG. 3 is a cross-sectional view schematically showing a BB'cross section of the transmission circuit integrated microwave generator of the embodiment shown in FIG. Further, FIG. 4 is a cross-sectional view schematically showing a CC'cross section of the transmission circuit integrated microwave generator of the embodiment shown in FIG. Further, FIG. 5 is a perspective view schematically showing the ferromagnetic multilayer film magnetoresistive element shown in FIG. 2.

The transmission circuit-integrated microwave generating element 1 (hereinafter, for convenience, sometimes simply referred to as “microwave generating element 1”) of the embodiment shown in FIGS. 1 to 4 is a ferromagnetic multilayer film magnetic resistance element 10 (hereinafter, for convenience). , In some cases simply referred to as "magnetic resistance element 10"), the input side upper electrode (input side electrode) 11, the first transmission line (input side transmission line) 12, and the second transmission line (output side transmission line). ) 13, the output side upper electrode 14, the insulating layer 15, the input side lower electrode (ground electrode) 16A, the output side lower electrode (ground electrode) 16B, the lower strip line 17, and the substrate 18. To be equipped. Further, in the transmission circuit integrated microwave generating element 1 of the present embodiment, a pair of electrodes including an upper electrode (input side electrode) 11 on the input side and a lower electrode (ground electrode) 16A on the input side makes the device stronger. It is configured so that the magnetic multilayer film magnetoresistive element 10 can be energized. In the element 1 of the present embodiment, the ferromagnetic multilayer film magnetoresistive element 10 is arranged on the lower strip line (ground plane) 17, and the lower strip line 17 is on the input side as shown in FIGS. 1 to 4. Since it is connected to the lower electrode (ground electrode) 16A of the above, for example, the upper electrode (input side electrode) 11 on the input side and the lower electrode (ground electrode) 16A on the input side are electrically connected to the power supply. As a result, it is possible to energize the ferromagnetic multilayer film magnetoresistive element 10.

Further, in the microwave generation element 1 integrated with the transmission circuit, the first transmission line (input side transmission line) 12 and the second transmission line (output side transmission line) 13 are provided by the insulating layer 15 provided on the lower strip line 17. The upper strip line and the lower strip line (ground plane) 17 are electrically insulated from each other. Further, the insulating layer 15 is a layer formed on the lower strip line 17 so as to surround the periphery of the magnetoresistive element 10. Further, the second transmission line (output side transmission line) 13 is connected to the output side upper electrode 14, and the lower strip line 17 is connected to the output side lower electrode (ground electrode) 16B. The output side upper electrode 14 and the output side lower electrode (ground electrode) 16B form a pair of electrodes on the load side (output side).

The ferromagnetic multilayer film magnetoresistive element 10 used in such a transmission circuit-integrated microwave generating element 1 includes a magnetization free layer 10A, a spacer layer 10B, and a magnetization fixed phase 10C as a basic structure. .. As described above, the magnetoresistive element 10 having the ferromagnetic multilayer film has a three-layer structure of a magnetization free layer 10A / spacer layer 10B / magnetization fixed layer 10C as a basic structure. In such a magnetoresistive element 10, when a current is applied to the element 10, the direction of magnetization of the magnetization free layer 10A changes, and as a result, the resistance value of the element 10 changes. That is, for example, when a case where a DC current is applied to the ferromagnetic multilayer film of the magnetic resistance element 10 by a power source is examined, the magnetization in the magnetic free layer vibrates due to the spin transfer effect between the magnetic free layer 10A and the magnetization fixed layer 10B. However, the angle θ formed by the magnetization of the free magnetized layer and the magnetism of the fixed magnetized layer changes from moment to moment. With the change of the angle θ at this time, the low resistance value (element resistance) of the element 10 changes from moment to moment mainly due to the spin valve magnetoresistive effect. Such a phenomenon in which the element resistance changes from moment to moment is called "magnetic resistance". Along with such a change in element resistance, an AC component of voltage appears from the element, and a microwave signal can be obtained by extracting the AC component. As such a magnetoresistive element 10, a known ferromagnetic multilayer film magnetoresistive element using the so-called tunnel magnetic resistance (TMR) effect (for example, the magnetoresistive element described in International Publication No. 2011/039843, JP-A-2006 -The magnetoresistive element described in Japanese Patent Application Laid-Open No. -295908, etc.) can be appropriately used.

Further, in such a magnetoresistive element 10, the magnetization free layer 10A and the magnetization fixed phase 10C are both layers made of a ferromagnetic material. As the magnetization free layer 10A and the magnetization fixed phase 10C, those made of a ferromagnetic material used in a known ferromagnetic multilayer magnetoresistive sensor can be appropriately used. Examples of such a ferromagnet include a ferromagnet and a ferrimagnet. Here, the ferromagnetic substance refers to a substance having the property that the spin directions of all the substances are aligned in one direction in a certain macroscopic size (magnetic domain). Examples of such a ferromagnetic material include magnetic metals such as iron, cobalt and nickel, iron-cobalt and iron-nickel alloys. Further, in a ferrimagnetic substance, the spins of the substance are composed of a plurality of components (sub-lattices), and the spin directions of the respective components are antiparallel in a certain magnetic domain, but their sizes are not uniform. Therefore, it refers to a substance that has the property of generating finite magnetization in the whole substance.

The material of the magnetization free layer 10A and the magnetization stationary phase 10C is not particularly limited, but is made of Co, Ni, Fe or an alloy containing them (for example, cobalt-iron, cobalt-iron-boron). Is preferable. The magnetization free layer 10A is composed of a multilayer film in which a ferromagnetic film and a non-magnetic film are laminated (for example, a laminate of a film made of Fe and a film made of Cr, a film made of Co, and Cu. A laminate of films) may be appropriately used. When a ferrimagnetic material is used in the magnetization free layer 10A or the like, a known ferrimagnetic material such as ferrite or iron garnet may be appropriately used.

In the magnetoresistive element 10, the ratio of causing resonance vibration of magnetization does not have to be the entire magnetization free layer 10A (100%). For example, if 70 to 80% of the magnetization free layer 10A resonates, the state of magnetization can be changed macroscopically, so that sufficient performance can be obtained for oscillating microwaves.

Further, the spacer layer 10B is an intermediate layer between the magnetization free layer 10A and the magnetization fixed phase 10C in the element 10. Such a spacer layer 10B is preferably a layer made of MgO (magnesium oxide) or AlO (aluminum oxide), and has a large magneto-resistance (MR) ratio, so that a higher output can be obtained. Therefore, it is particularly preferable that the layer is made of MgO. As described above, when the magnetoresistive element 10 includes the spacer layer 10B made of MgO, the element 10 can be a tunnel magnetoresistive element having MgO as a tunnel barrier. When a tunnel magnetoresistive element having such an MgO tunnel barrier is used as the magnetoresistive element 10, spin-dependent tunnel conduction can be utilized, and the element has a high MR (magnetic resistance) ratio. It is also possible to increase the oscillation efficiency of 10.

The height (thickness) H of the magnetoresistive element 10 is preferably 10 to 100 nm. Further, when the height H is less than the lower limit, the magnetization tends to be insufficient, while when the height H exceeds the upper limit, the MR ratio tends to be small.

Further, in such a magnetoresistive element 10, the thickness (height) T of the spacer layer 10B is preferably 1 to 2.5 nm (more preferably 1.4 to 1.6 nm). If the thickness T is less than the lower limit, if the input voltage to the element 10 is increased in an attempt to increase the output, dielectric breakdown tends to occur and the element tends to be damaged. On the other hand, if the thickness exceeds the upper limit, the impedance increases. The voltage required to energize the current is several tens of kV or more, and the drive voltage of the element tends to deviate from the practical voltage range normally used in various devices.

In the magnetoresistive element 10, the resistance value (output impedance) of the element 10 can be freely set by adjusting the thickness (height) T of the spacer layer 10B, and the thickness can be made thicker. The output impedance can be made larger. For example, when the spacer layer 10B is a layer made of MgO, when the thickness T changes from 1 nm to 1.4 nm, the output impedance Z changes from about 50 Ω to about 1000 Ω. Here, the output P of the microwave oscillated from the ferromagnetic multilayer film magnetoresistive element 10 increases with the magnitude of the output impedance Z of the element 10. The relationship between the output P and the output impedance Z of the element 10 is based on the following equation (1):

(Note that P indicates the output of the microwave, I indicates the magnitude of the current, η indicates the spin torque polarization rate, MR'indicates the magnetic resistance ratio of the element 10, and θ indicates the magnetization of the magnetization free layer. The angle formed by the magnetization of the magnetized fixed layer is indicated, θ ₀ indicates the angle formed by the magnetization of the magnetized free layer when not energized and the magnetization of the magnetized fixed layer, and Δθ indicates that the magnetization of the magnetized free layer receives spin torque. The angle of aging movement around the angle of θ ₀ is indicated, and R (θ ₀ ) indicates the output impedance Z (resistance value of the spacer layer) of the element 10.)
Can be represented by. Therefore, for example, even when only the change in the magnitude of the output impedance Z (R (θ ₀ )) of the magnetoresistive element 10 is considered, the thickness T is changed from 1 nm to 1.4 nm as described above. When the output impedance Z of the element is changed from about 50Ω to about 1000Ω, the magnitude of the output impedance Z (R (θ ₀ )) becomes about 20 times. Therefore, the output P is calculated from the above formula. It becomes about 100 times, and the output P of the microwave from the magnetoresistive element 10 can be sufficiently increased. When a high-power ferromagnetic multilayer magnetic resistance element with a large element resistance is used in a conventional microwave generation element with an integrated transmission circuit, it is transmitted to the load side due to an impedance mismatch with the load side. The efficiency became low, and the output from the ferromagnetic multilayer magnetoresistive element could not be sufficiently transmitted to the load side. However, in the present invention, even when a high-output ferromagnetic multilayer magnetic resistance element having a large element resistance is used, the output impedance of the transmission circuit integrated microwave generator and the impedance on the load side are set in the strip line. In order to match (match), the output impedance of the transmission circuit integrated microwave generator is 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element (the impedance conversion ratio of 15% or less is ferromagnetic multilayer magnetism). Depending on the relationship between the output impedance of the resistance element and the impedance on the load side, the impedance may be 10% or less, 5% or less in some cases, or even 1% or less). Therefore, it is possible to efficiently transmit microwaves to the load side, and by using a high-output ferromagnetic multilayer magnetic resistance element with a large element resistance, the transmission circuit is integrated without using an amplifier. It is possible to efficiently increase the output of the microwave generating element.

In the present invention, from the viewpoint of increasing the output, the ferromagnetic multilayer film magnetoresistive element 10 has a ferromagnetic multilayer with an output impedance of 500 Ω or more (more preferably 800 Ω or more, further preferably 1000 Ω or more, most preferably 5000 Ω or more). A membrane magnetoresistive element is used. The upper limit of the output impedance of the ferromagnetic multilayer magnetic resistance element 10 is not particularly limited, but the output impedance is preferably 50 kΩ or less. If the output impedance is less than the lower limit, the output of the microwave from the element 10 becomes low and it becomes difficult to increase the output, or dielectric breakdown tends to occur and the element tends to be damaged. If it exceeds, the voltage required to energize the current becomes several tens of kV or more due to the increase in impedance, and the drive voltage of the element tends to deviate from the practical voltage range normally used in various devices.

Further, as such a magnetoresistive element 10, the ratio of the maximum resistance value to the minimum resistance value (MR ratio [(maximum resistance value) / (minimum resistance value)]), which changes depending on the magnetic field, is It is preferably 200% or more, and more preferably 500 to 2000%. If such an MR ratio is less than the lower limit, the output tends to be small.

Further, the ferromagnetic multilayer film magnetoresistive element 10 having a three-layer structure of a magnetization free layer 10A / spacer layer 10B / magnetization fixed layer 10C has an upper electrode (input side electrode) 11 on the input side and a lower electrode (ground electrode). It is electrically connected to 16A. Here, the upper electrode (input side electrode) 11 on the input side is in contact with the magnetization free layer 10A. On the other hand, the lower electrode (ground electrode) 16A is electrically connected to the magnetization fixing layer 10C via the lower strip line (ground plane) 17. As described above, in the present embodiment, the lower strip line (ground plane) 17 also functions as a part of the lower electrode of the magnetic multilayer film magnetoresistive element 10. Therefore, by electrically connecting the upper electrode 11 on the input side and the lower electrode (ground electrode) 16A on the input side to a DC power source, a DC current can be applied to the ferromagnetic multilayer magnetic resistance element 10. it can. As described above, in the present embodiment, the upper electrode 11 on the input side and the lower electrode (ground electrode) 16A on the input side function as a pair of electrodes of the magnetoresistive element 10.

Further, in the microwave generating element 1 of the present embodiment, the microwave generated from the ferromagnetic multilayer magnetoresistive element 10 can be transmitted via the upper electrode 11 on the input side so that the upper electrode on the input side can be transmitted. The first transmission line (input side transmission line) 12 is connected to 11. Then, in the microwave generating element 1 of the present embodiment, the upper strip line is formed by the first transmission line (input side transmission line) 12 and the second transmission line (output side transmission line) 13. As described above, since the upper strip line composed of the first transmission line 12 and the second transmission line 13 and the lower strip line 17 are connected to the ferromagnetic multilayer magnetoresistive element 10 directly or via an electrode. The upper strip line and the lower strip line (ground plane) 17 make it possible to transmit microwaves oscillated from the ferromagnetic multilayer magnetoresistive element 10.

Further, the second transmission line 13 of such an upper strip line is connected to the upper electrode 14 on the output side, while the lower strip line 17 is connected to the lower electrode (ground electrode) 16B on the output side. , The microwave transmitted via the upper strip line and the lower strip line (ground plane) 17 can be taken out to the outside (load side). As shown in FIGS. 1 to 4, the lower strip line 17 of the present embodiment is basically shaped to cover one surface of the insulating layer 15 except for a part of the input side.

Materials for forming such an electrode 11, a first transmission line 12, a second transmission line 13, an electrode 14, an electrode 16A, an electrode 16B, and a lower strip line (ground plane) 17 are not particularly limited and are known. Can be appropriately used, and examples thereof include gold, copper, platinum, titanium, aluminum, chromium, and iron. Since the Q value of the resonance characteristics of the first transmission line 12 and the second transmission line 13 affects the efficiency of the microwave transmission line, the materials of the first transmission line 12 and the second transmission line 13 are used. It is more preferable to use a material having as little electrical resistance as possible (for example, gold, copper, aluminum can be exemplified as suitable).

Further, the upper strip line composed of the first transmission line 12 and the second transmission line 13 and the lower strip line 17 are electrically insulated by the insulating layer 15. The material for forming such an insulating layer 15 is not particularly limited, and a material having a low dielectric loss tangent (tan δ) value (more preferably, a material having a dielectric loss tangent (tan δ) value of 0.01 or less in the GHz band). Can be preferably used. As a material for forming such an insulating layer 15, for example, alumina, silica, a fluororesin, a glass fiber resin, and yttrium iron garnet (YIG) can be preferably used from the viewpoint of dielectric loss tangent (tan δ). When the insulating layer 15 is formed in the vicinity of the ferromagnetic multilayer magnetic resistance element 10 by using a material made of a magnetic material, the magnetization in the magnetic material and the magnetization in the ferromagnetic multilayer film interact with each other and a loss occurs. When a magnetic material is used when forming the insulating layer 15, the portion of the insulating layer 15 in the vicinity of the ferromagnetic multilayer film magnetic resistance element 10 may be made of a material other than the magnetic material. It is preferable (that is, when YIG is used as one of the materials of the insulating layer 15, the portion in the vicinity of the ferromagnetic multilayer film magnetic resistance element 10 of the insulating layer 15 is made of a material other than YIG, and the exception portion thereof. Is preferably composed of YIG).

Further, such an insulating layer 15 preferably has a relative permittivity ε _r of 2 to 10, and more preferably 3 to 5. If the relative permittivity is less than the lower limit, the element size tends to increase, while if it exceeds the upper limit, the dielectric loss tangent (tan δ) tends to increase and the loss tends to increase.

Further, it is preferable that the thickness of such an insulating layer 15 matches the thickness H of the ferromagnetic multilayer magnetoresistive element 10 (STO).

Further, in the microwave generating element 1 of the present embodiment, in the upper strip line and the lower strip line 17 composed of the first transmission line 12 and the second transmission line 13, the output impedance of the microwave generating element 1 is set to a ferromagnetic multilayer. From the viewpoint of performing impedance conversion so that the impedance is 15% or less of the output impedance of the membrane magnetic resistance element 10, the first transmission line 12 is set to the frequency of the microwave output from the ferromagnetic multilayer magnetic resistance element 10. On the other hand, the first transmission line 12 and the second transmission line are used as anti-resonant transmission lines, and the second transmission line 13 is used as a transmission line that resonates with respect to the frequency of the microwave output from the ferromagnetic multilayer film magnetic resistance element 10. 13 is combined so as to magnetically resonate. Here, in order to explain the relationship between the first transmission line 12 and the second transmission line 13, only the portions of the first transmission line 12 and the second transmission line 13 formed on the insulating layer 15 are enlarged and schematically. The top view shown in FIG. 6 is shown in FIG.

In the microwave generating element 1 of the present embodiment, as shown in FIGS. 1 and 6, the first transmission line 12 and the second transmission line 13 are arranged in parallel and separated from each other (in a non-contact state). Moreover, all the end portions that are not in contact with the electrodes are released. Such a first transmission line 12 has a ferromagnetic multilayer film L1 in order to make the transmission line anti-resonant with respect to the frequency of the microwave output from the ferromagnetic multilayer magnetoresistive element 10. It is preferable that the wavelength is half the wavelength (λ / 2) of the microwave oscillated from the magnetoresistive sensor 10. Further, in order to make the second transmission line 13 a transmission line that resonates with respect to the frequency of the microwave output from the ferromagnetic multilayer magnetoresistive element 10, the electric length L2 is set from the ferromagnetic multilayer magnetoresistive element 10. It is preferable that the wavelength is one-fourth (λ / 4) of the wavelength of the oscillated microwave. With respect to the electric length (line length) L1 of the first transmission line 12 and the electric length (line length) L2 of the second transmission line 13, the effective relative permittivity ε _{e of the} microwave transmission circuit is set to be strong. When the wavelength of the microwave oscillated from the magnetic multilayer film magnetic resistance element 10 is λ, the following equations:

When the condition described in the above is satisfied, it may be determined that the electric length L1 is "half the wavelength of the microwave (λ / 2)", and the electric length L2 is "of the microwave". It may be determined that the wavelength is one-fourth of the wavelength (λ / 4). As described in such equations (2) and (3), the electrical length (line length) of the microstrip line is basically a wavelength corresponding to the effective permittivity of the microwave generation element integrated with the transmission circuit. It is preferable that the length is multiplied by the shortening rate. Here, the wavelength shortening rate is expressed by the formula:

It is a value obtained by. Further, in the effective relative permittivity ε _e , assuming that the widths of the first transmission line 12 and the second transmission line 13 are both W, the thickness of the insulating layer 15 is h, and the relative permittivity of the insulating layer 15 is ε _r. , The following formula:

Can be calculated by calculating.

From this point of view, it is preferable that the electric length L1 of the first transmission line 12 satisfies the condition described in the above formula (2), and the electric length L2 of the second transmission line 13 is described in the above formula (3). It is preferable to satisfy the above conditions. Further, in the transmission circuit integrated microwave generating element 1, the electric length (line length) L1 of the first transmission line 12 is described in the above formula (2) by using the calculation formulas (2) to (6). It is preferable to design so as to satisfy the conditions and to design the electric length (line length) L2 of the second transmission line 13 so as to satisfy the conditions described in the above formula (3).

The line width W (line width of the microstrip line) of the first transmission line 12 and the second transmission line 13 is not particularly limited, and can be appropriately set to an arbitrary size depending on the application and the like, and each is 10 μm to 1 mm. It is preferably 0.1 to 0.5 mm, and more preferably 0.1 to 0.5 mm. If the line width W is less than the lower limit, the Q value tends to decrease. Since the element size increases as the line width W increases, it is preferable to increase the line width W within the range of the target size according to the application and the like.

Further, the thickness of the first transmission line 12 and the thickness of the second transmission line 13 are each preferably thicker than the skin depth due to the skin effect, and more preferably twice or more thicker than the skin depth due to the skin effect. .. For example, when the skin depth due to the skin effect at a wavelength of 1 GHz is 5 μm and the microwave of the wavelength 1 GHz is transmitted, the thickness of the transmission lines 12 and 13 is more preferably 10 μm or more, respectively. ..

Further, the distance (gap) D between the first transmission line 12 and the second transmission line 13 is set so that the impedance conversion ratio (conversion rate) in the upper strip line and the lower strip line becomes a desired conversion rate. It is preferable to design in consideration of the line width and thickness of the one transmission line 12 and the second transmission line 13. The reason why the impedance conversion rate changes according to the distance D between the first transmission line 12 and the second transmission line 13 is that the coupling coefficient k of the magnetic resonance between the two transmission lines 12 and 13 becomes the distance D. This is because it changes accordingly.

In addition, such magnetic resonance between the first transmission line 12 and the second transmission line 13 is an even mode (even mode) from the viewpoint of further reducing the leakage of electromagnetic waves and improving the microwave output more efficiently. It is preferable that the Even Mode) is in a bound state. The "even mode" referred to here refers to a coupling mode in which an electric wall is formed. Further, as described above, when the first transmission line 12 and the second transmission line 13 are magnetically resonated to perform impedance conversion on the strip line and output microwaves, the ferromagnetic multilayer film magnetic resistance element 10 is used. Even when the output impedance Z of the above is increased to 500Ω or more, the impedance on the load side can be matched with the impedance, and high-output microwaves can be extracted more efficiently without using an amplifier or the like. ..

Further, the microwave generating element 1 of the present embodiment is formed on the substrate 18 as shown in FIG. The substrate 18 is not particularly limited, and a known substrate can be appropriately used. For example, a silicon substrate, a silicon substrate with a thermal oxide film, an oxide substrate (magnesium oxide, sapphire, alumina, etc.), a plastic substrate, a polyimide substrate, etc. Etc. can be used as appropriate.

Here, with reference to FIG. 7, a method that can be suitably adopted when a microwave is output from the transmission circuit-integrated microwave generating element 1 to the outside will be briefly described. Note that FIG. 7 is a schematic diagram schematically showing a preferred embodiment of a microwave oscillator (oscillator) including the transmission circuit-integrated microwave generating element 1. In such an oscillator, one end of the transmission circuit-integrated microwave generating element 1 is electrically connected to the DC power supply 20, and the other end is connected to the filter 30. Further, the filter 30 is connected to an antenna 40 (external antenna) for transmitting microwaves. In such an oscillator, the upper electrode 11 on the input side and the lower electrode 16A on the input side of the microwave generation element 1 integrated with the transmission circuit are electrically connected to the DC power supply 20, and the transmission circuit is transmitted from the DC power supply 20. It is possible to energize the ferromagnetic multilayer magnetic resistance element 10 in the integrated microwave generating element 1. Further, in such an oscillator, the output-side upper electrode 14 and the output-side lower electrode 16B of the transmission circuit-integrated microwave generating element 1 are connected to the input port of the filter 30, and the transmission circuit-integrated microwave is connected. The output-side upper electrode 14 and the output-side lower electrode 16B of the generating element 1 are connected to the antenna (load side) 40 via a filter.

The DC power supply 20 is not particularly limited, and a known one can be appropriately used. However, even when an element having a high output impedance is used as the ferromagnetic multilayer magnetoresistive element 10, a current can be applied. Moreover, from the viewpoint of applying a high current to increase the output, it is preferable to use a power supply having a voltage of 0.1 to 10 V. Further, the magnitude of the current I energized from the DC power supply 20 is preferably set to about 1 mA to 10 mA from the viewpoint of increasing the output.

Further, the filter 30 is not particularly limited, and a known filter can be appropriately used. For example, a general bandpass filter may be used. Further, the antenna 40 is not particularly limited, and an external antenna having a known configuration capable of outputting microwaves oscillated from the ferromagnetic multilayer magnetoresistive element 10 to the outside can be appropriately used. Such an antenna 40 may be, for example, a patch antenna or the like.

In such an oscillator, the output impedance of the ferromagnetic multilayer film magnetic resistance element 10 in the transmission circuit integrated microwave generating element 1 is 500Ω or more, but the output impedance of the element 10 is the load side antenna 40. Even if it is larger than the impedance of, as described above, in the lower and upper strip lines (microstrip lines) of the transmission circuit integrated microwave generating element 1, the output impedance of the transmission circuit integrated microwave generating element 1 (above). The output impedance of the second transmission line 13 of the element 1 of the embodiment) is converted into an impedance of 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element, and is connected to the load side antenna 40. Since it is possible to match the impedances between them, the output impedance of the ferromagnetic multilayer film magnetic resistance element 10 is set to 500Ω or more, and the microwave output from the element 10 is sufficiently high. The final microwave output can be improved, and the microwave can be oscillated at a sufficiently high output. In the present invention, the ferromagnetic multilayer magnetic resistance element 10 having a sufficiently high element resistance such that the output impedance is 500Ω or more (for example, 1000Ω or the like) is used, but it is assumed that the antenna 40 on the load side is used. Even when the impedance is as small as 50Ω, for example, in the transmission circuit integrated microwave generator 1 of the above embodiment, the distance D between the first transmission line 12 and the second transmission line 13 is appropriately adjusted. Since the impedance conversion ratio can be adjusted as appropriate, the impedances on the input side and load side should be matched by designing the first and second transmission lines, and high-output microwaves should be oscillated efficiently. Can be done. As a result, the output P of the microwave oscillated from the element 10 can be made sufficiently large (see the above equation (1)), and as a result, the output is very high from the microwave generating element 1 integrated with the transmission circuit. It is possible to oscillate microwaves with.

Next, the design flow of the transmission line (strip line) in the transmission circuit integrated microwave generation element 1 will be briefly described with reference to FIG.

In order to design such a transmission line (strip line), first, in step S1, the strength to be used for the microwave generation element 1 integrated with the transmission circuit is determined based on the target microwave frequency, output size, and the like. The type (design, etc.) of the magnetic multilayer film magnetoresistive element 10 is determined. For the design of such a ferromagnetic multilayer magnetoresistive element 10, the relationship between the thickness and output of the layer 10B and the output impedance and magnetism are determined in advance according to the material (for example, MgO) of the spacer layer 10B to be used. The relationship between the output of the microwave from the resistance element 10 and the like may be clarified, and the conditions (magnitude of output impedance, etc.) of the element 10 to be used may be determined so that a desired output can be obtained.

Next, in step S2, information such as the frequency of the microwave oscillated from the ferromagnetic multilayer magnetic resistance element 10 used and the relative permittivity and thickness of the insulating layer (insulating substrate) 15 for forming the transmission line is obtained. Based on this, the electric length L1 of the first transmission line 12 and the electric length L2 of the second transmission line 13 are determined so that magnetic resonance can be efficiently performed on the first transmission line 12 and the second transmission line 13. .. That is, in step S2, the electrical lengths L1 and L2 are determined so as to have appropriate lengths according to the design of the element 10 and the like in consideration of the relationships shown in the above equations (2) to (6). .. Next, in step S3, with respect to the first transmission line 12 and the second transmission line 13, the lines of the first transmission line 12 and the second transmission line 13 are set so that the Q value becomes a sufficient value in consideration of the transmission efficiency. Determine the width. When considering the relationships shown in the above equations (2) to (6) in step S2, steps S2 and S3 may be performed at the same time because the information of the line width W is used.

Next, in step S4, the size of the distance (gap) between the first transmission line 12 and the second transmission line 13 is large according to the magnitude of the output impedance of the ferromagnetic multilayer magnetoresistive element 10 and the impedance on the load side. To determine. By determining the design of the first transmission line 12 and the second transmission line 13 in this way, the first transmission line 12 and the second transmission line 13 are used as the upper strip line, and the upper strip line and the above-mentioned upper strip line are used. Even when the output impedance of the ferromagnetic multilayer film magnetic resistance element 10 to be used has a large value by performing impedance conversion on the lower strip line 17 of the above, microwaves having a target frequency and output according to the element 10 are used. Can be output.

The method for manufacturing such a transmission circuit-integrated microwave generator is not particularly limited, except that the upper stripline and the lower stripline are designed so as to enable the above-mentioned conditions of the present invention to be satisfied. May be appropriately produced by using a known method (a known method for producing a ferromagnetic multilayer magnetoresistive element, a known method for producing an insulating layer, a known method for producing a stripline, etc.). For example, a CVD method, a sputtering method, or the like may be appropriately used for film formation of each layer such as an insulating layer or a lower strip line, and a photolithography method, an etching method, or the like may be appropriately used in combination for patterning electrodes and transmission lines. You may.

As described above, a preferred embodiment of the transmission circuit integrated microwave generator of the present invention, a method suitable for its use, and the like (a method that can be suitably adopted when a microwave is output from the device to the outside, etc.) ) Have been described with reference to FIGS. 1 to 7, but the transmission circuit-integrated microwave generator of the present invention, its usage, and the like are not limited to those of the above-described embodiment.

For example, in the transmission circuit integrated microwave generator of the above embodiment, the upper strip line is formed by the first transmission line 12 and the second transmission line 13, and the first transmission line 12 and the second transmission line 13 However, as shown in FIGS. 1 and 6, the wiring is linear and parallel to each other. However, in the transmission circuit integrated microwave generator of the present invention, the first upper strip line is used. When the transmission line 12 and the second transmission line 13 are used, the configuration of the upper strip line is not limited to that of the above embodiment, and for example, one of the first transmission line 12 and the second transmission line 13 is used. Alternatively, the wiring may be configured in which both are parallelized. The "parallel wiring" referred to here will be briefly described with reference to FIGS. 9 and 10. FIG. 9 is a drawing schematically showing the relationship between the linear first transmission line 12 and the linear second transmission line 13 (the transmission line shown in FIG. 1 is simplified and schematically represented. is there). Here, the port (terminal) P1 in FIG. 9 conceptually shows the connection point (end) with the electrode portion of the magnetoresistive element 10 on the input side, and the port (terminal) P2 is the upper electrode 14 on the output side. The connection point (end) of is conceptually shown. On the other hand, FIG. 10 is a schematic diagram schematically showing the relationship between the first transmission line 12 and the second transmission line 13 when the second transmission line 13 is arranged in parallel (P1 and P2 are FIGS. 9). Is synonymous with). In the embodiment shown in FIG. 10, the second transmission line 13 is a parallel wiring. As shown in FIG. 10, at least a part of each of the parallelized lines of the second transmission line 13 is wired in parallel with the first transmission line 12. From the viewpoint of magnetic resonance. When the wiring is parallelized in this way, the coupling coefficient of magnetic resonance can be further improved, and the microwave transmission efficiency tends to be further improved. Therefore, from the viewpoint of microwave transmission efficiency, it can be said that it is preferable to parallelize the first transmission line 12 and / or the second transmission line 13. Further, even when the first transmission line 12 and / or the second transmission line 13 are parallelized, they are parallelized from the viewpoint of efficiently magnetically resonating the first transmission line 12 and the second transmission line 13. The electrical length from the open end of each line of the second transmission line to the connection point (end) with the electrode portion may satisfy the conditions described in the above equations (2) and (3), respectively. preferable.

Further, in the transmission circuit integrated microwave generator of the above embodiment, the first transmission line 12 and the second transmission line 13 constituting the upper strip line are linear, but the transmission of the present invention When the first transmission line 12 and the second transmission line 13 are used as the upper strip lines in the circuit-integrated microwave generator, the shapes of these transmission lines are not particularly limited to the above shapes, for example. As described above (as shown in FIG. 10), at least one of the first transmission line 12 and the second transmission line 13 may be arranged in parallel, and further, the first transmission line 12 and the second transmission line 12 may be arranged in parallel. Each of 13 may have a curved shape or a broken line shape. Note that FIG. 11 schematically shows the relationship between the first transmission line 12 and the second transmission line 13 when the first transmission line 12 and the second transmission line 13 have a polygonal line shape, respectively. As shown in FIG. 11, even when the shapes of the first transmission line 12 and the second transmission line 13 are not linear, the first transmission line 12 and the second transmission line 13 are efficiently magnetically resonated. Even in such a shape, the output impedance of the transmission circuit-integrated microwave generating element is 15% of the output impedance of the ferromagnetic multilayer magnetic resistance element in the lower and upper strip lines. Impedance conversion is possible so that the impedance is as follows. Further, even when the shapes of the first transmission line 12 and the second transmission line 13 are not linear, the viewpoint of efficiently magnetically resonating between the first transmission line 12 and the second transmission line 13. From one end (for example, ports P1 or P2 in FIGS. 10 and 11) to the other end (open end) of each transmission line (in the case of parallelization, each line) It is preferable that the conditions described in the above formulas (2) and (3) are satisfied. Further, it is desirable that the open end of the first transmission line 12 is aligned with the start point (port P2) of the second transmission line. As described above, the first transmission line 12 and the second transmission line 13 can be used by appropriately changing their shapes and the like as long as they have a configuration capable of magnetically resonating them.

Further, in the transmission circuit integrated microwave generator of the above embodiment, the upper strip line is composed of the first transmission line 12 and the second transmission line 13, and the lower strip line is a flat one (ground plane). However, the structures of the upper stripline and the lower stripline are not limited to the above-described form, and in the transmission circuit integrated microwave generator of the present invention, the transmission circuit is used in the lower part and the upper stripline. The structure may be such that the output impedance of the integrated microwave generating element can be impedance-converted so as to be 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element, for example, the lower strip line. May consist of a first transmission line 12 and a second transmission line 13.

Further, in the transmission circuit integrated microwave generator of the above embodiment, the lower strip line is used as a flat line (ground plane), and the upper part including the first transmission line 12 and the second transmission line 13 is used. The structure of the strip line and that of the lower strip line are different, but in the transmission circuit integrated microwave generator of the present invention, the structures of the upper strip line and the lower strip line are limited to the above-mentioned form. Instead, for example, as shown in FIG. 12, the upper strip line and the lower strip line may have the same shape and may be used like a so-called dipole antenna. In FIG. 12, reference numeral 12 indicates a first transmission line of the upper strip line, reference numeral 13 indicates a second transmission line of the upper strip line, and reference numeral P1 indicates a connection point with the upper electrode portion of the magnetic resistance element 10. (Port (terminal)) is conceptually shown, and reference numeral P2 conceptually indicates a connection point (port (terminal)) with the upper electrode 14 on the output side. Further, in FIG. 12, reference numeral 12'indicates a transmission line on the input side of the lower strip line, reference numeral 13'indicates a transmission line on the output side of the lower strip line, and reference numeral P3 is an electrode on the lower side of the magnetic resistance element 10. The connection point (port (terminal)) with the portion is conceptually shown, and the reference numeral P4 conceptually indicates the connection point (port (terminal)) with the lower electrode (ground electrode) 16B on the output side. Each transmission line forming the upper strip line and the lower strip line shown in FIG. 12 is wired so as to be in a mirror image state via an insulating layer. In this way, even when the upper strip line and the lower strip line are used as in the so-called dipole antenna, the design of the first transmission line and the second transmission line is appropriate as in the above embodiment. Therefore, in the lower strip line and the upper strip line, impedance conversion is performed so that the output impedance of the microwave generation element integrated with the transmission circuit becomes an impedance of 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element. It is possible to make it.

As described above, in the transmission circuit integrated microwave generating element of the present invention, the output impedance of the transmission circuit integrated microwave generating element is the output of the ferromagnetic multilayer film magnetic resistance element in the lower part and the upper strip line. If it is possible to perform impedance conversion so that the impedance is 15% or less of the impedance, either one of the lower and upper strip lines, or both of them, is the ferromagnetic multilayer film magnetic resistance. The first transmission line that is anti-resonant with respect to the frequency of the microwave output from the element and the second transmission line that resonates with respect to the frequency of the microwave may be combined so as to magnetically resonate.

Further, in the transmission circuit-integrated microwave generating element of the above embodiment, both the first transmission line 12 and the second transmission line 13 are in an open state at the end (termination). When the first transmission line 12 and the second transmission line 13 are used as upper strip lines in the transmission circuit integrated microwave generating element of the present invention, the end portion of the first transmission line 12 and the end portion of the second transmission line 13. The states of may be independently open or short-circuited. This point will be briefly described with reference to FIG. FIG. 13 is a schematic diagram conceptually showing the relationship between the upper strip line and the lower strip line (ground plane). Although the insulating layer is not shown in FIG. 13 so that the relationship between the upper strip line and the lower strip line can be easily understood, the upper strip line and the lower strip line are in the form shown in FIGS. 1 to 4. Similar to the one, it is formed separately on both sides of the insulating layer (insulating substrate). Here, in the embodiment shown in FIG. 13, the first transmission line 12 and the lower strip line (ground plane) 17 are short-circuited at the end (terminating portion) on the opposite side of the first transmission line 12 from the port P1. (Note that in FIG. 13, the dotted line with the reference numeral S is a conceptual representation of the short-circuited state). Such a short-circuited state is easily formed, for example, by forming a via hole at the terminal portion of the first transmission line 12 of the insulating layer existing between the upper strip line and the lower strip line (ground plane). It is possible to do. On the other hand, in FIG. 13, the end portion (termination portion) of the second transmission line 13 on the opposite side to the port P2 is in an open state. As described above, in the upper strip line and the lower strip line (ground plane) of the embodiment shown in FIG. 13, the end portion of the first transmission line 12 is short-circuited and the end portion of the second transmission line 13 is open. It has become. Regarding the short-circuited and opened states at the end portions of the first transmission line 12 and the second transmission line 13, the output impedance of the transmission circuit-integrated microwave generator in the lower strip line and the upper strip line is described above. If it is possible to convert the impedance so that the impedance is 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element, any part of the terminal other than P1 and P2 is open or short-circuited. You may. That is, the short-circuited and opened states of the first transmission line 12 and the second transmission line 13 forming the upper strip line other than P1 and P2 are described in the following (I) to (IV):
(I) Both the terminal portion of the first transmission line 12 and the terminal portion of the second transmission line 13 are open (see FIG. 1);
(II) The end of the first transmission line 12 is open and the end of the second transmission line 13 is short-circuited;
(III) The end of the first transmission line 12 is short-circuited and the end of the second transmission line 13 is open (see FIG. 13).
(IV) Both the end of the first transmission line 12 and the end of the second transmission line 13 are short-circuited;
It may be in any of the above states.

The short-circuit and open states at the ends of the first transmission line 12 and the second transmission line 13 forming the upper strip line are the states of (I) above (both the first transmission line 12 and the second transmission line 13). Is in the open state), as described above (as described in the embodiment shown in FIG. 1 above) from the viewpoint of more efficiently resonating the first transmission line 12 and the second transmission line 13 to cause magnetic resonance. In), it is preferable that the electric length of the first transmission line 12 is half the wavelength (λ / 2) of the wavelength of the microwave oscillated from the ferromagnetic multilayer film magnetic resistance element 10, and the second It is preferable that the electric length of the transmission line 13 is one-fourth the wavelength (λ / 4) of the wavelength of the microwave oscillated from the ferromagnetic multilayer magnetic resistance element 10. The relationship between the short-circuited and open states (states (I) to (IV) above) of the terminal portions of the first transmission line 12 and the second transmission line 13 and the suitable electrical length of each transmission line is shown. Shown in 1. Note that λ in the table indicates the wavelength of the microwave to be transmitted.

In this way, in the short-circuit and open states shown in (I) to (IV) above, the electrical lengths of the first transmission line 12 and the second transmission line 13 forming the upper strip line are shown in the table, respectively. It is preferable to have an electric length as shown in 1, and when such a condition is satisfied, it becomes possible to more efficiently resonate the first transmission line 12 and the second transmission line 13 to cause magnetic resonance. In the upper strip line, impedance conversion can be performed so that the impedance is 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element. As described above, in the present invention, the electric length is appropriately set according to the short-circuited and opened states (states (I) to (IV) above) of the terminal portions of the first transmission line 12 and the second transmission line 13. As a result, at least one of the lower and upper strip lines resonates or anti-resonates with respect to the frequency of the microwave output from the ferromagnetic multilayer magnetic resistance element, and the strong. The magnetic multilayer film may be combined so as to magnetically resonate with a resonance or anti-resonant second transmission line with respect to the frequency of the microwave output from the magnetic resistance element. As described above, in the present invention, the first transmission line 12 is separated from each other (not directly electrically conducted) at at least one of the lower portion and the upper strip line depending on the state of the terminal portion and the like. And the second transmission line 13 may be combined so as to magnetically resonate.

Further, in the transmission circuit integrated microwave generating element of the above embodiment, as the ferromagnetic multilayer film magnetic resistance element, the magnetic resistance element in which the magnetizing free layer 10A / spacer layer 10B / magnetizing fixing layer 10C is laminated in this order from above. Although No. 10 is used, the configuration of the ferromagnetic multilayer magnetic resistance element that can be used in the present invention is not limited to that of the above embodiment, and for example, the vertical positions of the magnetized free layer and the magnetized fixed layer are not limited to those of the above embodiment. May be reversed, and other layers that can be used for the ferromagnetic multilayer magnetic resistance element (for example, the extraction electrode layer directly formed on the element itself, the magnetization direction of the magnetization fixing layer are retained. A support layer for supporting the magnetism, a support layer for adjusting the magnetization direction of the free magnetizing layer, a capping layer, etc.) may be appropriately laminated. For example, the element 10 itself may be designed to have a laminated structure of an upper electrode / a magnetization free layer 10A / a spacer layer 10B / a magnetization fixing layer 10C / a lower electrode.

Further, in the embodiment shown in FIG. 7, a filter or the like is connected to the transmission circuit integrated microwave generating element 1 to output microwaves, but the transmission circuit integrated microwave generating element of the present invention is used. The method of outputting microwaves is not limited to this, and for example, it may be output without using a filter. Further, in the transmission circuit integrated microwave generation element of the present invention, other components (antenna, etc.) do not necessarily have to be used in order to output microwaves by using the microwave generation element, for example, the upper strip line and the upper strip line. A strip line (microstrip line) composed of a lower strip line may output microwaves to the outside so as to function as an antenna. As described above, the transmission circuit-integrated microwave generator of the present invention can be configured to be usable as a microwave oscillator using a known ferromagnetic multilayer magnetoresistive sensor, depending on the application. Depending on the situation, other components (antenna, filter, etc.) may be used as appropriate.

Further, in the transmission circuit integrated microwave generator of the above embodiment in which the upper strip line is composed of the first transmission line and the second transmission line, the lengths L1 and L2 from the connection portion with the electrode to the open end are used. Although the preferable electric length of the transmission line is described, the configuration of the upper strip line and the like is not limited to that shown in the above embodiment, and for example, the first transmission line and the second transmission line are used. Even in the case of this, as in the embodiment shown in FIG. 14 (see Example 1 described later), the wiring not involved in magnetic resonance (the portion indicated by reference numeral 13L) is further coupled to the second transmission line 13. It may be combined with other transmission lines as appropriate, such as in such a configuration. In this case, the part involved in magnetic resonance (transmission line indicated by reference numeral 13 or code 12: the "part involved in magnetic resonance" here means to cause magnetic resonance in the transmission line. It is preferable that the electrical length of (referring to the required portion) is designed so as to satisfy the above-mentioned electrical lengths L1 and L2. As described above, even when the upper strip line includes the first transmission line and the second transmission line, the configuration of the upper strip line is not limited to that shown in FIGS. 1 and 6, and the present invention is not limited to that shown. The design can be appropriately changed, for example, by appropriately using a connection line (wiring having a different thickness, etc.) between the electrode and the first and / or second transmission lines, as long as the effect of the above is not impaired.

As described above, the transmission circuit-integrated microwave generating element of the present invention includes a ferromagnetic multilayer magnetic resistance element and a lower strip for transmitting microwaves oscillated from the ferromagnetic multilayer magnetic resistance element. A transmission circuit-integrated microwave generating element including a line and an upper strip line, the output impedance of the ferromagnetic multilayer magnetic resistance element is 500Ω or more, and the transmission circuit in the lower and upper strip lines. Microwaves oscillated from the ferromagnetic multilayer magnetic resistance element by impedance conversion so that the output impedance of the integrated microwave generator is 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element. Is transmitted using the lower part and the upper strip line, and the specific shape, design, and the like thereof are not limited to those of the above embodiment.

Such a transmission circuit-integrated microwave generating element of the present invention utilizes a ferromagnetic multilayer magnetic resistance element having an output impedance of 500Ω or more (more preferably, a ferromagnetic multilayer magnetic resistance element having an output impedance of 1000Ω or more). Even in such a case, it is possible to perform impedance conversion in the lower portion and the upper strip line to transmit (propagate) the microwave using the lower portion and the upper strip line. Therefore, according to the present invention, it is possible to improve the output of the microwave oscillated from the microwave generation element integrated with the transmission circuit by increasing the output P of the microwave from the ferromagnetic multilayer magnetic resistance element. is there. The transmission circuit-integrated microwave generating element of the present invention integrates a minute ferromagnetic multilayer magnetoresistive element and a microwave transmission circuit, without using an amplifier or the like. Since it is possible to improve the output, it is also possible to increase the output and reduce the size of the communication device by using this. As described above, the microwave generation element integrated with the transmission circuit of the present invention can increase the output of microwaves without using an amplifier. Therefore, for example, a mobile phone, wireless communication, or an in-vehicle device. It can be suitably used for a microwave oscillator or the like used in radar, satellite broadcasting, or the like.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Example 1)
[Considerations for designing transmission lines (1)]
As described above, when the first transmission line 12 and the second transmission line 13 as shown in FIG. 6 are used, the electrical length L1 of the first transmission line 12 satisfies the equation (2) and the second transmission line 13 It is preferable to design so that the electric length L2 satisfies the above formula (3). Therefore, for example, as described later, on one surface of an insulating substrate (material: glass fiber resin) having a relative permittivity ε _r of 3.55 and a thickness of 0.5 mm, a length of about 100 mm and a width of W The first transmission line 12 made of copper satisfying the conditions of 0.3 mm and a thickness of 20 μm, and the second transmission line 13 made of copper satisfying the conditions of a length of about 50 mm, a width W of 0.3 mm and a thickness of 20 μm. A case where a copper thin film satisfying the condition of a thickness of 20 μm is formed on one surface of the other surface of the insulating substrate is calculated based on the above equations (2) and (3). When the first transmission line 12 and the second transmission line 13 satisfying the above conditions are combined, the microwave that can be transmitted most efficiently by these transmission lines is a microwave having a frequency of 873 MHz (λ is 343 mm). You can see that it becomes a wave. That is, if the frequency of the target microwave is 873 MHz, theoretically, the first transmission line 12 satisfying the conditions of a length of about 100 mm, a width W of 0.3 mm, and a thickness of 20 μm has an electric length L1. It can be determined that the wavelength satisfies the above equation (2) (half the wavelength of the microwave (λ / 2)), the length is about 50 mm, and the width W is 0.3 mm. The second transmission line 13 satisfying the condition of the thickness of 20 μm is determined to have an electric length L2 satisfying the above equation (3) (one-fourth wavelength (λ / 4) of the microwave wavelength). it can. As is clear from such considerations, the electrical lengths L1 and L2 of the transmission line can be determined using the above equations (2) and (3) from the data such as the target frequency magnitude and the relative permittivity of the substrate. It can be designed, and conversely, the optimum frequency for transmission on the transmission line is calculated using the above equations (2) and (3) from data such as the characteristics of the transmission line and the permittivity of the substrate. It is also possible to do. In addition, it is also possible to appropriately consider the optimum design according to the purpose, taking into consideration the items (2) to (3) to be examined for the design of the transmission line, which will be described later.

[Considerations for designing transmission lines (2)]
In order to design the optimum transmission line for the target microwave, six measurement samples as schematically shown in FIG. 14 are formed (note that the first transmission line 12 and each measurement sample are formed. Using a vector network analyzer (commonly known as "VNA": trade name "E5071C" manufactured by Keyence Co., Ltd.), the first transmission line 12 and the first transmission line 12 and the second transmission line 12 The relationship between the distance (gap) D between the two transmission lines 13 and the optimum value [unit: Ω] of the port impedance on the microwave input side (port P1 side) was measured. Since the relationship between the first transmission line 12 and the second transmission line 13 in the measurement sample as shown in FIG. 14 is conceptually the same as that shown in FIG. 6, the same applies hereinafter to FIG. Use the code of.

First, an insulating substrate (material: glass fiber resin) having a thickness of 0.5 mm and a specific dielectric constant of 3.55 is used, and a first transmission line having a form as shown in FIG. 14 is formed on one surface of the substrate. By forming the 12 and the second transmission line 13 using copper as a material, an upper strip line composed of the first transmission line 12 and the second transmission line 13 is formed on one surface of the substrate, and the other side of the substrate is formed. A lower strip line (ground plane) made of copper having a thickness of 20 μm is formed on one surface over the entire surface, and a distance (gap) D between the first transmission line 12 and the second transmission line 13 is formed. Six measurement samples were formed, which differed only in the size of. Here, in the six measurement samples manufactured, the first transmission line 12 and the second transmission line 13 have a large distance D between the closest lines between the first transmission line 12 and the second transmission line 13. They were arranged in parallel so that the distances were 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm, respectively (the closest line portion was made parallel). .. In each measurement sample, reference numeral P1 indicates an input side port connected to the first transmission line 12, and reference numeral P2 indicates an output side (load side) port connected to the second transmission line 13. The portion of the code 13L is a connection line (connection portion to the port P2) connecting the second transmission line 13 and the port P2, and has a different line width from the portion of the second transmission line 13 to be magnetically resonated (a portion). The transmission line was formed so as to be a portion corresponding to the upper electrode 14 in FIG. Further, such a connection line 13L is a connection line having an impedance of 50Ω (this is because the distance (gap) D between the first transmission line 12 and the second transmission line 13 is short, so that the first transmission is carried out as it is. Since it is difficult to connect the connector of the vector network analyzer (VNA) to the part of port P2 without contacting the line 12, the connection has an impedance that matches the port impedance (50Ω) of the port P2 to which it is connected. It was used to connect the wires and draw out the connection point between the port P2 and the second transmission line 13. The impedance value of 50Ω is the impedance of the port P2 connected to the vector network analyzer at the time of measurement. Since it is 50Ω, it is combined with it. Hereinafter, such a connection line 13L will be referred to as a “50Ω connection line 13L”). Here, the line width of each of the first transmission line 12 and the second transmission line 13 is 0.3 mm, and the thickness of each line is 20 μm. Further, the first transmission line 12 has a length X from the port P1 to the open end of about 100 mm (theoretically, a half wavelength length (λ / 2) of a microwave having a wavelength of 343 mm). It is a transmission line having the electrical length (length L2 calculated by the above equation (2)): see the above consideration (1)). Further, the second transmission line 13 (the portion excluding the connection portion 13L) has a length Y from the connection point with the connection line 13L to the open end of about 50 mm (theoretically, a microwave having a wavelength of 343 mm). A transmission line having an electrical length of a quarter wavelength length (λ / 4) (length L2 calculated by equation (3) above: see item (1) above). The 50Ω connecting wire 13L connected to the port P2 has a width of 1.0 mm, a thickness of 20 μm, and a length Z of 10 mm (material: copper).

Next, using each of the six measurement samples, a vector network analyzer (commonly known as "VNA": trade name "E5071C" manufactured by Keyence Co., Ltd.) was used for the measurement samples, and the frequency: 0.1 GHz to By inputting a high frequency of 1.5 GHz and using the port impedance conversion function to obtain the port impedance on the port P1 side where the peak of the value of S21 of the S parameter measured by the vector network analyzer is the highest, the first The relationship between the distance (gap) between the transmission line 12 and the second transmission line 13 and the optimum value [unit: Ω] of the port impedance Z on the microwave input side (port P1 side) was measured. At the time of measurement, the impedance on the port P2 side of the vector network analyzer was set to 50Ω. The obtained results are shown in FIG.

From the results shown in FIG. 15, in a system in which the line width W and the thickness of the first transmission line 12 and the second transmission line 13 are fixed, the output impedance is set to 50Ω by changing the size of the distance (gap) D. It was found that the optimum value of the port impedance Z on the input side (port P1 side) of the microwave can be changed. Based on these facts, the distance (gap) D between the first transmission line 12 and the second transmission line 13 depends on the magnitude of the output impedance of the ferromagnetic multilayer magnetic resistance element and the magnitude of the impedance on the load side. It is possible to adjust the coupling coefficient of magnetic resonance by changing the magnitude of, and it is also possible to easily match the output impedance of the ferromagnetic multilayer magnetic resistance element with the impedance impedance on the load side. I understand. Further, from such a result, according to the design of the transmission line to be used, the distance (gap) D between the first transmission line 12 and the second transmission line 13 and the micro when the output impedance is set to 50Ω are obtained in advance. It can be seen that it is possible to design a circuit according to the target frequency and output by finding the relationship with the optimum value of the port impedance on the input side of the wave.

[Considerations for designing transmission lines (3)]
Apart from the above consideration (2), six measurement samples as shown in FIG. 14 were formed (measurement samples had different line widths W), and a vector network analyzer (commonly known as "VNA": Keyence). The line width of the first transmission line 12 and the second transmission line 13 and the port impedance of the microwave input side (port P1 side) when the output impedance is 50Ω, using the product name “E5071C” manufactured by the company). The relationship with Z [unit: Ω] was measured (the relationship between the first transmission line 12 and the second transmission line 13 in the measurement sample as shown in FIG. 14 is conceptually shown in FIG. Since it is the same as that of the above, the same reference numerals as those in FIG. 6 are used below). In such a measurement, the distance (gap) D is fixed at 0.4 mm, and the line width W of the first transmission line 12 and the second transmission line 13 is used as the measurement sample instead of the distance (gap) D. The configuration is the same as that of the measurement sample used in the measurement of the above examination item (2), except that each is set to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, and 0.6 mm, respectively. Measurement samples (6 pieces) were produced. Then, except that the measurement samples (6 pieces) are used, the microwave input side (similar to the method adopted when the optimum value of the port impedance Z is measured in the measurement of the above examination item (2)) The optimum value of the port impedance Z on the port P1 side) was measured. The obtained results are shown in FIG.

From the results shown in FIG. 16, in a system in which the distance D between the first transmission line 12 and the second transmission line 13 and the thickness of each line are fixed, the size of the line width W of the first transmission line 12 and the second transmission line 13 is large. It was found that by changing the value, it is possible to change the optimum value of the port impedance Z on the input side (port P1 side) of the microwave when the output impedance is 50Ω. Based on these facts, the first transmission line 12 and the first transmission line 12 and the size of the distance (gap) D are taken into consideration according to the size of the output impedance of the ferromagnetic multilayer magnetic resistance element and the size of the impedance on the load side. It can also be seen that by changing the magnitude of the line width W between the second transmission lines 13, it is possible to match the output impedance of the ferromagnetic multilayer magnetic resistance element with the impedance impedance on the load side. Further, from such a result, the target frequency is obtained by obtaining the relationship between the line width W of the first transmission line 12 and the second transmission line 13 and the impedance in advance according to the design of the transmission line to be used. It can be seen that it is also possible to design the circuit according to the output.

Further, by appropriately using the data shown in FIGS. 15 and 16, for example, in the design flow shown in FIG. 8 described above, the target frequency, output, magnitude of impedance on the load side, etc. It becomes possible to form the first transmission line 12 and the second transmission line 13 of an appropriately designed design according to the above, and such measurement can be performed according to the material to be used (for example, the material of the insulating substrate or the transmission line). It can be seen that it is possible to design a more efficient transmission circuit by performing it appropriately. When the optimum value of the port impedance on the input side of the microwave and the magnitude of the output impedance of the ferromagnetic multilayer magnetoresistive element are matched, the ferromagnetic multilayer magnetoresistive element can be efficiently output. It is clear that it will be possible.

[Considerations for designing transmission lines (4)]
As shown in FIG. 17, a transmission line having the same design as the first transmission line 12 manufactured in the measurement sample used in the measurement of the above examination item (2) has a thickness of 0.5 mm and a relative permittivity of 3. A lower strip line (ground plane) made of copper having a thickness of 20 μm is formed on one surface of an insulating substrate (material: glass fiber resin) of .55 and has a thickness of 20 μm on the other surface of the substrate. It was formed and used as a measurement sample (A). Then, the impedance characteristic of the transmission line is measured using such a measurement sample (A), and the S parameter S11 is measured using a vector network analyzer (trade name "E5071C" manufactured by Keyence Co., Ltd.), and this is used as the impedance. Obtained by conversion. The measurement was performed in the frequency range of 0.1 GHz to 1.5 GHz. In this way, the impedance characteristics of the first transmission line 12 were obtained.

Further, as shown in FIG. 18, a transmission line having the same design as the second transmission line 13 manufactured in the measurement sample used in the measurement of the above examination item (2) has a thickness of 0.5 mm and a relative permittivity. A lower strip line made of copper having a thickness of 20 μm formed on one surface of an insulating substrate (insulating layer) made of glass fiber resin having a thickness of 3.55 and having a thickness of 20 μm on the other surface of the substrate. A ground plane) was formed and used as a measurement sample (B). Then, using such a measurement sample (B), the impedance characteristic of the transmission line is measured by using a vector network analyzer (trade name "E5071C" manufactured by Keyence Co., Ltd.) to measure the S-parameter S11, and this is used as the impedance. Obtained by converting to. The measurement was performed in the frequency range of 0.1 GHz to 1.5 GHz. In this way, the impedance characteristics of the second transmission line 13 were obtained.

Results obtained by these measurements (impedance characteristics of transmission lines formed in the measurement samples (A) and (B), respectively: a graph showing the relationship between the impedance and frequency of the transmission lines formed in each measurement sample. ), The measurement result in the frequency range of 0.1 GHz to 1.1 GHz is shown in FIG.

From the results shown in FIG. 19, when the microwave frequency is at about 0.8 GHz (about 800 MHz), the measurement of the first transmission line 12 formed on the measurement sample (A) (the above-mentioned examination item (2)). The first transmission line 12 formed on the measurement sample used) is a so-called anti-resonant transmission line, and the transmission line formed on the measurement sample (B) (the above-mentioned examination item (2). ) Has the same configuration as the second transmission line 13 formed on the measurement sample used in the measurement of), it can be seen that it is a so-called resonance transmission line. Assuming that the specific dielectric constant of the insulating substrate does not change even under the measurement environment at the time of measuring the impedance characteristics, theoretically, when the microwave frequency is 873 MHz, the first length is about 100 mm. It can be determined that the transmission line 12 has an electric length L1 satisfying the above equation (2) (half the wavelength of the microwave (λ / 2)), and has a length of about 50 mm. It can be determined that the second transmission line 13 has an electric length L2 satisfying the above equation (3) (one-fourth wavelength (λ / 4) of the microwave wavelength) (the above-mentioned examination item (1)). See). However, in the actual measurement, from the results shown in FIG. 19, the measurement samples (A) and (B) have a peak near about 800 MHz, and the frequency is slightly different from the frequency of 873 MHz. I understand. It is considered that such a wavelength shift is caused by a change in the specific dielectric constant of the insulating substrate or the like depending on the measurement environment (humidity, temperature, etc.) (Note that the specific dielectric constant of the insulating substrate is described above). Numerical value: 3.55 is a catalog value), under the above-mentioned measurement environment of impedance characteristics, the length: about the wavelength of the wavelength at the peak position (position of about 800 MHz) shown in FIG. The electric length L1 of the first transmission line 12 of 100 mm is an anti-resonant transmission line (satisfying the above equation (2): half the wavelength of the microwave (λ / 2)) and has a length. S: The electric length L2 of the second transmission line 13 of about 50 mm becomes a resonance transmission line (satisfying the above equation (3): one-fourth wavelength (λ / 4) of the wavelength of the microwave). It is thought that there is. From these results, it can be seen that it is possible to measure the data according to the usage environment and design the optimum frequency and the electrical length of the transmission line. That is, based on such data, it is possible to design a transmission line when the target microwave frequency is set to about 800 MHz when used under the same conditions as the measurement environment. ..

[Measurement of transmission efficiency]
Among the measurement samples formed in the above examination item (2) based on the above examination items (2) to (4), the measurement sample having a distance D of 0.3 mm (hereinafter, for convenience, simply "for measurement" in some cases. Using the port impedance conversion function of a vector network analyzer (trade name "E5071C" manufactured by Keyence Co., Ltd.) using a sample (X), the port impedance of port P1 is set to 800Ω and the impedance of port P2 is set to 800Ω. A microwave with a frequency of 0.1 GHz to 1.5 GHz was input from the port P1 to the port P2 with 50 Ω, and the transmission efficiency of the microwave was obtained. In this way, the transmission efficiency of the measurement sample (X) was measured. Among the results of such measurements, FIG. 20 shows the measurement results in the frequency range of 0.5 GHz to 1.2 GHz. As the transmission efficiency referred to here, the value of S21 of the S parameter measured by the vector network analyzer is used, and the peak value of S21 is squared (formula: [transmission efficiency] = (S21 peak) ² ). The value obtained (by calculating) was adopted.

For comparison with the measurement sample (X), the measurement sample connected from the connection point with the port P1 to the connection point of the connection line 13L of the port P2 with a continuous transmission line ( Measurement sample (X) described above, except that the measurement sample (hereinafter, for convenience, simply referred to as "measurement sample (Y)") in which the upper strip line consisting of one transmission line is formed is used. In the same manner as the method for measuring the transmission efficiency of the measurement sample (Y), the transmission efficiency of the microwave when the microwave is input from the port P1 to the port P2 of the measurement sample (Y) is in the frequency range of 0.1 GHz to 1.5 GHz. I asked for it. Among the results of such measurements, FIG. 20 shows the measurement results in the frequency range of 0.5 GHz to 1.2 GHz.

As is clear from the results shown in FIG. 20, in the measurement sample (X), the value of the transmission efficiency when a microwave having a frequency of about 0.8 GHz (about 800 MHz) is incident is 81%. In contrast to the extremely high value, in the measurement sample (Y), the transmission efficiency value is about 30% at any frequency in the range of 0.5 GHz to 1.2 GHz. It was. From these results, in the measurement sample (X), when the microwave having a frequency of about 0.8 GHz is transmitted, the first transmission line 12 and the second transmission line 13 magnetically resonate (coupling), and the first is The upper strip line consisting of the first transmission line 12 and the second transmission line 13 and the lower strip line convert the impedance in the direction in which the impedance of port 1 becomes smaller by 800Ω, and as a result of approaching the load of port 2 to 50Ω, each It is considered that the impedance of the port was matched and the microwave was transmitted efficiently. On the other hand, in the measurement sample (Y), since the impedance conversion was not performed, a mismatch (mismatch) occurred between the impedance of 800Ω of the port 1 and the impedance of 50Ω of the port 2. It is probable that the transmission efficiency was as low as 30% at any frequency in the range of 5 GHz to 1.2 GHz.

Considering this point with reference to the result shown in FIG. 19, the measurement is performed when the target microwave frequency is considered to be about 0.8 GHz as described above from the result shown in FIG. It is clear that the transmission line of the sample (A) for measurement (having the same configuration as the first transmission line 12 of the sample (X) for measurement) is a so-called anti-resonant transmission line, while the sample for measurement (X) It is clear that the transmission line of B) (having the same configuration as the second transmission line 13 of the measurement sample (X)) is a so-called resonant transmission line. In the measurement sample (X), the line widths of the first transmission line 12 and the second transmission line 13 are each 0.3 mm, the distance (gap) between them is 0.3 mm, and the vector network. The optimum value of the port impedance at which the peak of the S parameter measured by the analyzer is the highest is about 800Ω as shown in FIG.

Taking these points into consideration, the measurement sample (X) is composed of a first transmission line 12 and a second transmission line 13 when transmitting a microwave having a frequency of about 0.8 GHz. In the upper strip line and the lower strip line, 15% or less (actually, about 6% (50Ω / 800Ω) of the impedance on the high frequency input side (port impedance on the port P1 side: 800Ω) can be calculated and obtained. It is clear that impedance conversion is performed between the input side (port P1 side) and the output side (port P2 side) of the microwave so that the impedance becomes (possible)). Based on these results, in the measurement sample (X), the first transmission line 12 and the second transmission line 13 each have a frequency of about 0.8 GHz (about 800 MHz) with respect to microwaves. It is clear that it functions like a parallel resonator (first resonator), a series resonator (second resonator), which causes impedance conversion in the lower and upper strip lines and ports. Since it became possible to match the impedance of P1 with the impedance of port P2, the transmission efficiency for microwaves having a frequency of about 0.8 GHz was significantly improved as compared with the measurement sample (Y). Conceivable.

Based on the various measurement results as described above, the upper strip line consisting of the first transmission line 12 and the second transmission line 13 formed in the measurement sample (X) is the microwave input to the transmission line. When the frequency of is about 0.8 GHz (about 800 MHz), a transmission line that is anti-resonant with respect to the microwave (first transmission line) and a transmission line that resonates with respect to the microwave (second transmission line). ) And (see FIG. 19), which makes it possible to efficiently transmit microwaves with a frequency of about 800 MHz using magnetic resonance, which is sufficient. It can be seen that microwaves can be output efficiently (see FIG. 20). From such a result, it is clear that according to the present invention, it is possible to increase the output of microwaves having a desired frequency.

As described above, according to the present invention, it is possible to provide a microwave generation element integrated with a transmission circuit capable of increasing the output of microwaves without using an amplifier.

Therefore, the transmission circuit integrated microwave generator of the present invention is useful as a microwave oscillator or the like used in mobile phones, wireless communications, in-vehicle radars, satellite broadcasting, and the like.

1 ... Transmission circuit integrated microwave generator, 10 ... ferromagnetic multilayer magnetic resistance element, 10A ... magnetized free layer, 10B ... spacer layer, 10C ... magnetized stationary phase, 11 ... input side upper electrode (input side electrode) , 12 ... 1st transmission line (input side transmission line), 13 ... 2nd transmission line (output side transmission line), 14 ... output side upper electrode, 15 ... insulation layer, 16A ... input side lower electrode (ground electrode) ), 16B ... Lower electrode (ground electrode) on the output side, 17 ... Lower strip line, 18 ... Substrate, L1 ... Electric length of the first transmission line (line length), L2 ... Electric length of the second transmission line (line length) ), W ... line width, D ... distance (gap) between the first transmission line and the second transmission line, H ... ferromagnetic multilayer film height (thickness) of magnetic resistance element, T ... ferromagnetic multilayer film magnetism Thickness of spacer layer in resistance element, R ... ferromagnetic multilayer film Diameter of upper surface of magnetization free layer in magnetic resistance element, 20 ... DC power supply, 30 ... filter, 40 ... antenna, P1 to P4 ... transmission circuit port ( Terminal), 12'... transmission line on the input side of the lower strip line, 13' ... transmission line on the output side of the lower strip line, 13L ... connection line between port P2 and the second transmission line.

Claims (2)

A transmission circuit-integrated microwave generating element including a ferromagnetic multilayer magnetic resistance element and a lower stripline and an upper stripline for transmitting microwaves oscillated from the ferromagnetic multilayer magnetic resistance element.
The output impedance of the ferromagnetic multilayer magnetoresistive element is 500Ω or more, and
In the lower part and the upper strip line, impedance conversion is performed so that the output impedance of the microwave generation element integrated with the transmission circuit becomes 15% or less of the output impedance of the ferromagnetic multilayer magnetic resistance element, and the strength is changed. A microwave generation element integrated with a transmission circuit, characterized in that microwaves oscillated from a magnetic multilayer film magnetic resistance element are transmitted by using the lower portion and the upper strip line. At least one of the lower part and the upper strip line is a first transmission line anti-resonant with respect to the frequency of the microwave output from the ferromagnetic multilayer magnetic resistance element, and with respect to the frequency of the microwave. The transmission circuit-integrated microwave generator according to claim 1, wherein the second transmission line of resonance is combined so as to magnetically resonate.