WO2012083441A1 - Artificial magnetic material, artificial magnetic device, artificial magnetic material reflecting wall and artificial magnetic material transparent wall - Google Patents

Artificial magnetic material, artificial magnetic device, artificial magnetic material reflecting wall and artificial magnetic material transparent wall Download PDF

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Publication number
WO2012083441A1
WO2012083441A1 PCT/CA2011/001422 CA2011001422W WO2012083441A1 WO 2012083441 A1 WO2012083441 A1 WO 2012083441A1 CA 2011001422 W CA2011001422 W CA 2011001422W WO 2012083441 A1 WO2012083441 A1 WO 2012083441A1
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Prior art keywords
artificial magnetic
magnetic material
substrate
gap
ring
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French (fr)
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Toshiro KODERA
Christophe Caloz
Dimitrios SOUNAS
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type
    • H01P7/08—Strip line resonators
    • H01P7/082—Microstripline resonators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/201—Filters for transverse electromagnetic waves
    • H01P1/203—Strip line filters
    • H01P1/20327—Electromagnetic interstage coupling
    • H01P1/20354—Non-comb or non-interdigital filters
    • H01P1/20381—Special shape resonators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/20—Frequency-selective devices, e.g. filters
    • H01P1/201—Filters for transverse electromagnetic waves
    • H01P1/203—Strip line filters
    • H01P1/2039—Galvanic coupling between Input/Output
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0086—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/004—Control by varying the supply voltage

Definitions

  • ARTIFICIAL MAGNETIC MATERIAL ARTIFICIAL MAGNETIC MATERIAL, ARTIFICIAL MAGNETIC DEVICE, ARTIFICIAL MAGNETIC MATERIAL REFLECTING WALL AND ARTIFICIAL MAGNETIC MATERIAL
  • the present disclosure relates to an artificial magnetic material which exhibits properties nearly equivalent to gyromagnetic properties of ferrite materials, and more particularly to an artificial magnetic material which exhibits non-reciprocal properties nearly equivalent to gyromagnetic properties without application of a bias magnetic field.
  • the present disclosure relates to applications (e.g. devices) of the present artificial magnetic material.
  • a reciprocal device is a network component that satisfies the reciprocity theorem and its scattering matrix corresponds to a symmetric matrix
  • a non-reciprocal device does not satisfy the reciprocity theorem and its scattering matrix is not a symmetric matrix.
  • Isolators and circulators are representative non-reciprocal devices, which are widely used in microwave and millimeter wave systems to achieve stabilization and multifunction.
  • magnetic materials such as ferrites
  • ferrites are used to realize the non- reciprocity of the non-reciprocal devices.
  • the magnetic moment of electron spin which determines the magnetic properties of a ferrite, starts precession when an external magnetic field is applied to the ferrite. This precession of the magnetic moment yields the magnetic gyrotropy of ferrites.
  • the non-reciprocity of non-reciprocal devices is caused by the magnetic gyrotropy.
  • a metamaterial is an artificial material that consists of small metallic and dielectric particles which are periodically aligned in space, with periodicity much smaller than the wavelength.
  • a metamaterial exhibits properties that cannot be found in natural materials.
  • split-ring resonators exhibit a unique property of negative permeability, but cannot provide non-reciprocity. Therefore, split-ring resonators can only be used for the implementation of reciprocal devices. Non-reciprocal devices cannot be realized with split- ring resonators.
  • Non-reciprocal devices which use ferrite materials require a permanent magnet for the production of an external bias magnetic field.
  • This requirement for an external magnetic field has set limits on the applicability of ferrite-based devices.
  • the existence of a bulky permanent magnet prevents size miniaturization.
  • increasing the operation frequency of the device needs a stronger magnet because the operation frequency of the ferrite device is proportional to the intensity of the bias magnetic field.
  • the biasing requirement completely presents application.
  • a non-reciprocal boundary which uses the non-reciprocal properties of a ferrite medium requiring a bias magnetic field perpendicular to the boundary.
  • the permanent magnet pair which has to be put in front and back of the boundary, disturbs any wave approaching the ferrite surface.
  • the non-reciprocal boundary by conventional ferrite material becomes impossible.
  • Rare-earth metals are indispensable constituents of ferrite materials and strong permanent magnets.
  • the total amount of the deposits of rare-earth metals in the earth is very small, and the production is limited to very few specified countries and areas. . Therefore, an alternative technology independent of rare-earth metals is extensively required.
  • an artificial magnetic material comprises: a conductor pattern, which is ring-shaped with a gap; and a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap.
  • the artificial magnetic material described above may further comprise: a planar back side conductor, which is in parallel with a plane which includes the conductor pattern.
  • a pair of the conductor patterns may be disposed parallel with each other, and planes which include one of the conductor patterns are in parallel with each other.
  • the unidirectional component preferably is a variable gain amplifier.
  • the unidirectional component preferably is a field effect transistor.
  • an artificial magnetic material device comprises: a planar substrate comprising an insulating material; a conductor pattern, which is ring-shaped with a gap, and which is disposed on a front surface of the substrate; a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap; a transmission line, which is disposed on the front surface of the substrate; a planar back side conductor, which is disposed on a rear surface of the substrate; an input port, which inputs a signal to the transmission line; and an output port, which outputs a signal from the transmission line.
  • an artificial magnetic material device comprises: a planar substrate comprising an insulating material; a conductor pattern, which is ring-shaped with a gap, and which is disposed on a front surface of the substrate; a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap; a planar back side conductor, which is disposed on a rear surface of the substrate; an input port which radiates an electromagnetic wave to a front side of the substrate; and an output port which outputs an electromagnetic wave reflected by the substrate.
  • an artificial magnetic material device comprises: a planar substrate comprising an insulating material; a pair of conductor patterns, which are ring-shaped with a gap, and which are disposed parallel with each other on a front surface and a rear surface of the substrate; a unidirectional component, which transmits a signal unidirectionally to a single rotational direction, and which is inserted in the gap of each conductor pattern; an input port, which radiates an electromagnetic wave to the front side or the rear side of the substrate; and an output port, which outputs an electromagnetic wave penetrating through the substrate.
  • the unidirectional component preferably is a variable gain amplifier.
  • the unidirectional component preferably is a field effect transistor.
  • an artificial magnetic material wall that reflects an electromagnetic wave comprises: a planar substrate comprising an insulating material; a conductor pattern, which is ring-shaped with a gap, and which is disposed on a front surface of the substrate; a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap; and a planar back side conductor, which is disposed on a rear surface of the substrate, wherein the front surface of the substrate is capable of reflecting an electromagnetic wave.
  • the unidirectional component preferably is a variable gain amplifier.
  • the unidirectional component preferably is a field effect transistor
  • an artificial magnetic material wall that is transparent with an electromagnetic wave comprises: a planar substrate comprising an insulating material; a pair of conductor patterns, which are ring-shaped with a gap, and which are disposed parallel with each other on a front surface and a rear surface of the substrate; and a unidirectional component, which transmits a signal unidirectionally to the single rotational direction, and which is inserted in the gap of each conductor pattern, wherein the substrate is transparent with an electromagnetic wave.
  • the unidirectional component preferably is a variable gain amplifier.
  • the unidirectional component preferably is a field effect transistor.
  • Fig. 1 is a schematic representation of a gyro-resonator 1, which is a constituent of the artificial magnetic material according to the present disclosure.
  • Fig. 2 is a schematic representation of an equivalent circuit of a gap portion of the gyro resonator 1.
  • FIG. 3 is a perspective view showing an external schematic representation of the gyro resonator 1.
  • FIG. 4 is a perspective view showing an external schematic representation of another type gyro resonator 12.
  • FIG. 5 is a schematic representation of an example device 6 for an evaluation using a plurality of gyro resonators 1.
  • Fig. 6 is a graph showing measured results, proving non-reciprocity of the device 6 of Figure 5.
  • Fig. 7 is a perspective view showing a schematic representation of a computing model of an artificial magnetic material.
  • Fig. 8 is a front view of the schematic representation of the computing model of the artificial magnetic material of Figure 7.
  • Fig. 9 is a plan view of the schematic representation of the computing model of the artificial magnetic material of Figure 7.
  • Fig. 10 is a graph showing an intensity distribution of an electric field in the artificial magnetic material.
  • Fig. 11 is a schematic representation of a circulator 7 comprising the present artificial magnetic material of Figure 7.
  • Fig. 12 is a graph showing measured results, which indicate the property of the circulator 7.
  • Fig. 13 is a graph showing measured results, which demonstrate the non- reciprocal property of the circulator 7
  • Fig. 14 is a graph showing measured results, which demonstrate the non- reciprocal property of the circulator 7.
  • Fi 9- 15 is a schematic representation of a transparent wall comprising the present artificial magnetic material.
  • FIGs. 16 (a - e) are schematic representations showing various applications of the present artificial magnetic material..
  • Fig. 17 is a schematic representation of a conventional split-ring resonator. Description of Embodiments
  • the artificial magnetic material according to the present disclosure possesses non-reciprocal properties without any ferrite and permanent magnet. Any non-reciprocal device which uses the present artificial magnetic material can be miniaturized and its weight can be reduced as much as possible, since a permanent magnet for a bias magnetic field is not needed. In addition, the operating frequency can be easily increased, since no strong bias magnetic field is required to increase the operation frequency.
  • the artificial magnetic material according to the present disclosure does not contain rare-earth elements, which are indispensable constituents of ferrites and permanent magnets. Because the artificial magnetic material is independent of rare-earth metals, various applications for various fields are enabled.
  • the artificial magnetic material is suitable for wide-area reflecting walls and transparent walls because it does not require a permanent magnet for the production of an external bias magnetic field.
  • the present disclosure provides an artificial magnetic material which exhibits non- reciprocity to realize non-reciprocal components.
  • a split-ring resonator used for the realization of a conventional artificial magnetic material, will be explained.
  • the split-ring resonator is widely studied in the context of artificial materials called metamaterials.
  • a metamateriai is an artificial material that consists of small metallic and dielectric particles, spatially aligned according to a periodic lattice with periodicity much smaller than the wavelength.
  • a metamateriai exhibits properties that cannot be observed in natural materials.
  • an artificial magnetic material which exhibits negative permeability can be realized by utilizing the split-ring resonator.
  • FIG. 17 schematically depicts a conventional split-ring resonator.
  • the split ring shaped conductor patterns of 91 and ⁇ 2 are disposed to form a double ring structure 9.
  • Conductor patterns 91 and 92 allow both rightward and leftward electromagnetic wave propagation as shown by arrows. At a resonance frequency, superposition of these two waves form a standing wave along the double ring structure 9.
  • the split-ring resonator 9 exhibits the unique property of negative permeability, but it does not exhibit non-reciprocity. Therefore, the split-ring resonator can be used only for the realization of reciprocal devices. Non-reciprocal devices cannot be realized with split- ring resonators.
  • non-reciprocal devices By using ferrite material, non-reciprocal devices can be realized.
  • the origin of the non-reciprocity is the magnetic gyrotropy of ferrites as described above, in a ferrite to which the external magnetic field is applied, the precession of the magnetic moment of electron spin happens in one direction and this fact leads to non-reciprocity.
  • the gyro resonator 1 shown in Fig. 1 has been developed. It is designed so as to achieve a response equivalent to a gyrotropic response of ferrite materials.
  • the constitution of the gyro resonator 1 will now be described with reference to Fig. 1.
  • the split ring shaped (C-character shaped) conductor pattern 2 is disposed on a front side surface (the upper surface) of a substrate 0 of an insulator (dielectric).
  • a backside surface (a lower surface) of the substrate 10 is totally covered by a conductor, which is named a backside conductor 21 (Fig. 3).
  • These conductors are typically made of metal, but they can also be made of any other conducting material.
  • a field effect transistor (FET) 3 is disposed in a gap of the conductor pattern .
  • One edge of the conductor pattern 2 is connected to a drain terminal of FET 3, and another edge is connected to a gate terminal of FET 3 through a capacitor 4.
  • a source terminal of FET 3 is connected to the backside conductor 21 on the lower surface of the substrate through a hole.
  • the FET 3 has two source terminate, both connected to the backside conductor 21.
  • a direct-current (DC) bias voltage V D D is applied to the drain terminal of FET 3 through a meander line 5.
  • the FET 3 operates as a unidirectional signal component from the gate to the drain terminal. Because of the functioning of the FET 3, an electromagnetic wave oan propagate only in the arrow direction, and it cannot propagate in reverse direction. Therefore, the resonance of the gyro resonator 1 is formed by a traveling wave, and not a standing wave.
  • Fig. 2 is a schematic representation of an equivalent circuit of the gap portion of the gyro resonator 1 ,
  • One edge of the conductor pattern 2 is connected to the drain terminal of the FET 3, and the other edge is connected to the gate terminal of the FET 3 through a capacitor 4.
  • a traveling wave propagates toward the direction shown by arrows.
  • the source terminal of the FET 3 is connected to a ground conductor, and the DC bias voltage V DD is applied to the drain terminal of the FET 3 through the meander line 5.
  • the meander line 5 can be composed for example as a series circuit of an inductor L and a resistor R.
  • the meander line 5 may be made by a thin line pattern so that the characteristic impedance of the line is much larger than the corresponding of the conductor pattern 2.
  • the large difference of the impedance provides the large impedance mismatch, which prevents a generated RF signal from leaking to the meander line 5.
  • the meander shape produces even a larger inductance. As a result, the traveling wave in the conductor pattern 2 does not enter the meander line 5, and the power supply is decoupled from the gyro resonator 1.
  • the following configuration parameters were applied: conductor pattern 2 of 2.0 mm line width, meander line 5 of 0.3 mm line width, capacitor 4 of 1 pF capacitance, and a Renesus 3210S01 by Electronics Corporation was used as the FET 3.
  • the circumference of the conductor pattern 2 corresponded to a half wavelength at the operation frequency.
  • the conductor pattern 2 and the FET 3 provided a 180-degree phase shift each, and, as a result, a traveling wave resonance occured in the gyro resonator 1.
  • the resonance frequency of the gyro resonator was 6.7 GHz.
  • the gain of FET 3 can be easily controlled by varying the DC bias voltage VDD, which is provided by a DC power source.
  • VDD DC bias voltage
  • the DC bias voltage V D D was set much lower than fi e rated value (4.0 V) to decrease the gain much less than under normal use. More particularly, in that embodiment where the FET used was a NE3210S01, the DC bias voltage VDD was driven at less or equal to 0.2 V.
  • Fig. 3 is a perspective view showing an external schematic representation of the gyro resonator 1.
  • the split ring shaped (C-character shaped) conductor pattern 2 is disposed on the front side surface of the substrate 10 of insulator.
  • the backside surface of the substrate 10 is totally covered by the backside conductor 21.
  • the FET 3, and other components, which operate as a unidirectional component, are shown in simplified expression. An electromagnetic wave generated thereby propagates only in the arrow direction, and cannot propagate in reverse direction. Therefore, the resonance of the gyro resonator 1 is formed by a traveling wave, and not a standing wave.
  • the embodiment of the gyro resonator 1 of Figure 3 with the backside conductor 21 shown In Fig. 3 is not the only possible embodiment.
  • Another exemplary embodiment schematically shown in Fig. 4 can be realized, in this particular embodiment, the split ring shaped (C-character shaped) conductor pattern 2 is disposed on the front side surface of the substrate 10 of insulator, and a similar conductor pattern 2 is disposed on the backside surface of the substrate 10.
  • the FET 3 and other components shown in simplified expression function as a unidirectional component.
  • the circuit shown in Fig. 1 is disposed in the gap portion of each conductor pattern 2.
  • a unidirectional component is disposed in each conductor pattern 2 on front side and backside surfaces of the substrate 10 of the insulator. Resulting electromagnetic waves propagate in the single rotational direction, as indicated by the arrow.
  • the resonance of the gyro resonator .12 is also formed by a traveling wave, and not a standing wave.
  • the gyro resonator 12 shown in Fig. 4 is equivalent to the gyro resonator 1 shown in Fig. 3, considering the mirror image of the conductor pattern 2 by the backside conductor 21.
  • both electromagnetic fields in gyro resonators 1 and 2 are equivalent to each other, as are the resonance frequencies.
  • the electromagnetic field in the gyro resonator 12 is equivalent to the electromagnetic field in the gyro resonator 1.
  • an electromagnetic wave cannot penetrate the gyro resonator 1 in thickness direction because of the backside conductor 21.
  • an electromagnetic wave can penetrate the gyro resonator 12 in thickness direction, which renders the gyro resonator 12 suitable for applications related to transparent walls and transparent type devices.
  • the gyro resonator 1 is suitable for applications related to reflecting walls and reflecting type devices. Both embodiments of gyro resonators 1 and 12 exhibit non-reciprocity similar to the magnetic gyrotropy of ferrites, as will be described in detail below.
  • the electromagnetic field in the gyro resonator 12 shown in Fig. 4 is equivalent to the electromagnetic field in the gyro resonator 1 shown in Fig. 3 as described above.
  • Analyses of electromagnetic fields in the gyro resonators 1 and 12 have revealed that unidirectional rotation of magnetic moment occur in both embodiments.
  • This rotation of magnetic moment in gyro resonators 1 and 12 is a phenomenon similar to the precession of magnetic moment in ferrites.
  • the gyro resonators 1 and 12 exhibit non-reciprocity similar to the magnetic gyrotropy of ferrites because of this rotation of magnetic moment.
  • FIG. 5 shows a schematic representation of an exemplary device 6 for an evaluation using a plurality of gyro resonators 1.
  • the examplary device 6 includes eight gyro resonators 1 disposed on an upper surface of a substrate of insulator (dielectric), A lower surface of the substrate is covered by a backside conductor, which plays the role of the ground.
  • the same DC bias voltage V D D is applied to all the FETs of the gyro resonators 1.
  • the DC bias voltage V DD is adjustable.
  • the gyro resonators 1 are disposed so as to support a traveling wave in the same direction. In Fig. 5, the traveling wave, which is resonating, rotates clockwise on each conductor pattern 2.
  • a transmission pattern 63 for example a microstrip line, is linearly formed so as to be close to all gyro resonators 1.
  • the width of the transmission pattern 63 is the same 2.0 mm as the width of the conductor patterns 2.
  • the transmission pattern 63 is not in contact with the conductor patterns 2, and a minimum interval of 0.1 mm separates the transmission pattern 63 and the patterns 2.
  • a first port 61 and a second port 62 are disposed in both ends of the transmission pattern 63 as an input and an output ports of the examplary device 6.
  • a shorting patch 64 is disposed on a lower side of a middle part of the transmission pattern 63. The shorting patch 64 connects one side of the transmission pattern 63 to the backside conductor (ground).
  • the field distribution in a microstrip line on a non-gyrotropic dielectric substrate concentrates on both sides of a width of the transmission line irrespective of the propagation direction.
  • the field distribution is symmetric with respect to the propagation direction.
  • the electric field distribution of a microstrip line on a biased ferrite substrate concentrates on one side with respect to the propagation direction.
  • the intensity of the field takes a maximum value on the left side and a minimum one on the right side, as facing to the propagation direction.
  • the electromagnetic field should concentrate on one side with respect to the propagation direction. This displacement of the electromagnetic field leads to a difference in the transmissivity of a propagating wave from the first port 61 to the second port 62 and from the second port 62 to the first port 61. This difference is due to the fact that the shorting patch 64 to the ground is disposed on one side of the transmission pattern 63.
  • Fig. 6 is a graph showing the measured transmission characteristics of the exemplary device 6, which demonstrate non-reciprocity.
  • the DC bias voltage VDD was set at 0.15 V.
  • the vertical axis in the graph of Fig. 6 corresponds to transmission coefficients S 2 i and S 12 in dB, and the horizontal axis in the graph corresponds to the frequency in GHz.
  • the transmission coefficient S 21 corresponds to the transmissivity from the first port 61 to the second port 62
  • the transmission coefficient S12 corresponds to the transmissivity from the second port 62 to the first port 61.
  • the thick line in the graph corresponds to the measured transmission coefficient S 2 1, and the thin line in the graph corresponds to the measured transmission coefficient S1 2 .
  • the measured transmission coefficient S1 2 As shown in Fig.
  • the transmission coefficients S 2 i and S 12 have different values from 6.7 GHz to 6.8 GHz in frequency. Therefore, the examplary device 6 operates as a non-reciprocal device, and the artificial magnetic material consisting of the gyro resonator 1 provides non- reciprocity.
  • a significant difference between the transmission coefficients S 2 i and Si 2 in the examplary device 6 is not measured when the gyro resonator 1 is deactivated by setting the DC bias voltage V D D - 0 V.
  • the response of the examplary device ⁇ becomes very unstable when the DC bias voltage VDD is set to 0.22 V, voltage at which the gyro resonator 1 begins to oscillate.
  • FIG. 7 is a perspective view showing the configuration of the computing model of the artificial magnetic material.
  • Fig. 8 is the front view of the computing model.
  • Fig. 9 is the plan view of the computing model.
  • Directions of coordinate axes are shown in Fig. 7.
  • the origin of the coordinates is positioned to the right and lower corner of the computing model.
  • the origin of the coordinates is the position shown in Fig. 8 and Fig. 9.
  • the coordinates in Fig. 7 only show directions of coordinate axes.
  • the computing model of the artificial magnetic material is represented by a rectangular parallelepiped in which x direction size is a, y direction size is a and z direction size is 2c.
  • the upper half part (the region of c ⁇ z ⁇ 2c) of the rectangular parallelepiped is a vacuum space.
  • the intensity distribution of the electric field of an electromagnetic wave propagating from first port P1 to second port P2 and from second port P2 to first port P1 has been calculated by a numerical analysis. Shown in Fig, 8, the electric field of the propagating electromagnetic wave lies to z direction.
  • the numerical analysis is performed by a computer software which executes an electromagnetic field simulation performed in accordance with a finite element method.
  • Fig. 10 is a graph showing an intensity distribution of the z-direction electric field E z in the artificial magnetic material.
  • the horizontal axis in the graph of Fig. 10 corresponds to the coordinate of y axis, and the vertical axis corresponds to the intensity of the electric field E z .
  • the thick line in the graph corresponds to the intensity distribution of the electric field E z of an electromagnetic wave propagating from first port P1 to second port P2, and the thin line in the graph corresponds to the intensity distribution of the electric field E z of an electromagnetic wave propagating from second port P2 to first port P1.
  • the graph shows that the electric field distribution concentrates on one side , and that the electric field distribution concentrates on an opposite side when the electromagnetic wave propagates to the reverse direction.
  • the artificial magnetic material provides non-reciprocity.
  • Fig. 11 is a schematic representation of an example of a circulator 7 utilizing the previously described artificial magnetic material.
  • the circulator 7 is formed on the upper surface of a dielectric substrate of insulator, and the backside of the substrate is covered with a ground conductor.
  • the circulator 7 has three input and output ports as first port 71 , second port 72 and third port 73. Three transmission lines are formed from each port to a circular conductor disposed on the center of the dielectric substrate.
  • Six gyro resonators 1 are disposed closely to transmission lines. It has been confirmed that the circulator 7 exhibits general circulator properties when the circulator 7 is operated with the application of an appropriate DC bias voltage V DD .
  • Fig. 12 to Fig. 14 are graphs snowing measured results, demonstrating the property of the circulator 7.
  • the vertical axis in the graph of Fig. 12 corresponds to the transmission coefficients Si 2 and S 2 i in dB, and the horizontal axis in the graph corresponds to the frequency in GHz.
  • the transmission coefficient S 21 corresponds to the transmissivity from the first port 71 to the second port 72
  • the transmission coefficient S 12 corresponds to the transmissivity from the second port 72 to the first port 71.
  • the thick line in the graph corresponds to the measured transmission coefficient S 2 i
  • the thin line in the graph corresponds to the measured transmission coefficient S 12 .
  • the vertical axis in the graph of Fig. 13 corresponds to the transmission coefficients S23 and S 32 in dB, and the horizontal axis in the graph corresponds to the frequency in GHz.
  • the transmission coefficient S32 corresponds to the transmissivity from the second port 72 to the third port 73
  • the transmission coefficient S23 corresponds to the transmissivity from the third port 73 to the second port 72.
  • the thick line in the graph corresponds to the measured transmission coefficient S32
  • the thin line in the graph corresponds to the measured transmission coefficient S 2 3-
  • the vertical axis in the graph of Fig. 14 corresponds to the transmission coefficients and S31 in dB, and the horizontal axis in the graph corresponds to the frequency in GHz.
  • the transmission coefficient S13 corresponds to the transmissivity from the third port 73 to the first port 7
  • the transmission coefficient S 31 corresponds to the transmissivity from the first port 71 to the third port 73.
  • the thick line in the graph corresponds to the measured transmission coefficient S 13l
  • the thin line in the graph corresponds to the measured transmission coefficient S31.
  • each transmissivity of different transmission direction has different values from 7.0 GHz to 8.0 GHz in frequency. Therefore, the circulator 7 exhibits the property of a non-reciprocal device.
  • Fig. 15 is a schematic representation of a transparent wall comprising the artificial magnetic material 11.
  • the split ring shaped conductor patterns are formed on the front side and backside surfaces of a substrate of insulator.
  • a plurality of gyro resonators uniformly disposed on the substrate constitute the artificial magnetic material 11 .
  • An electromagnetic wave can penetrate the artificial magnetic material 11 in thickness direction.
  • This embodiment of the artificial magnetic material 11 is suitable for applications to transparent walls and transparent type devices.
  • the electromagnetic field of an electromagnetic wave penetrating the artificial magnetic material 11 has been calculated by a numerical analysis.
  • the numerical analysis was performed by a computer software which executed an electromagnetic field simulation performed in accordance with a finite element method. As a result, it was confirmed that the plane of polarization of the electromagnetic wave rotates when the electromagnetic wave penetrates the artificial magnetic material. This phenomenon is so- called Faraday rotation, and it is the same one which occurs in a biased ferrite.
  • the gyro resonator 12 and the artificial magnetic material 11 exhibit non-reciprocity similar to ferrites.
  • the gyro resonator 1 formed on the dielectric substrate operates as an artificial magnetic material, and that it can be used as a substitute of a biased ferrite medium.
  • the bias magnetic field is indispensable for the ferrite medium, but it is unnecessary for the artificial magnetic material made of the gyro resonator.
  • the non-necessity for a bias magnetic field results in the elimination of the permanent magnets from the non-reciprocal devices. This fact enables the miniaturization of the device.
  • the present gyro resonator and resulting artificial magnetic material do not need high bias magnetic field for high frequency operation, enabling the easy increase in the operation frequency.
  • the present artificial magnetic material does not contain any rare-earth materials, which are indispensable constituents of ferrites and permanent magnets, providing indicates that promising substitution of ferrites which strongly depend on valuable rare-earth materials.
  • FIG. 6 is a schematic representation representing various applications of the present artificial magnetic material.
  • Fig. 16(a) schematically depict an application of a transmission line type device which uses the present artificial magnetic material.
  • the artificial magnetic material 11 is an insulator (dielectric) substrate on which gyro resonators 1 are disposed at proper positions.
  • the transmission line type device has four input and output ports 81 - 84, which are connected with the transmission line network 85 formed on the artificial magnetic material 11.
  • an arbitrary non- reciprocal device can be constituted.
  • the number of input and output ports is not limited to four, but it is arbitrary.
  • Fig. 16(b) is a schematic representation of a transparent type device which uses the present artificial magnetic material.
  • the artificial magnetic material 1 is an insulator (dielectric) substrate on which gyro resonators 12 are disposed at proper positions, and it may be one shown in Fig. 15 for example.
  • the electromagnetic wave from the input and output port 81 penetrates the artificial magnetic material 1, and it is transferred to the input and output port 82.
  • This transparent type device also is a non-reciprocal device because of non-reciprocity of the artificial magnetic material 11.
  • Fig. 16(c) shows a schematic representation of a reflecting type device which uses the present artificial magnetic material.
  • the artiftciai magnetic material 11 comprises an insulator (dielectric) substrate on which gyro resonators 1 are disposed at proper positions.
  • the electromagnetic wave from the input and output port 81 is reflected on the surface of the artificial magnetic material 11, and it is transferred to the input and output port 82.
  • This transparent type device also is a non-reciprocal device because of non- reciprocity of the artificial magnetic material 11.
  • Fig. 16(d) schematically depicts the use of the present artificial magnetic material 11 as a reflecting wall.
  • the artificial magnetic material 11 comrpises an insulator (dielectric) substrate on which gyro resonators 1 are disposed at proper positions.
  • the reflecting wall utilizing the artificial magnetic material 11 can be used as outer walls of buildings and surfaces of airplanes or the like.
  • the polarization of the electromagnetic wave reflected by the artificial magnetic material 11 can be rotated non- reciprocally. Contrary to ferrites, the artificial magnetic material 11 does not require a permanent magnet for the production of an external bias magnetic field, it is thus suitable for applications related to wide-area reflecting walls.
  • Fig. 16(e) schematically depicts the use of the artificial magnetic material 1 as a transparent wall.
  • the artificial magnetic material 11 comprises an insulator (dielectric) substrate on which gyro resonators 12 are disposed at proper positions, for example as shown in Fig. 15.
  • the transparent wall utilizing the present artificial magnetic material 1 can be used as windowpanes of buildings and transparent windows of airplanes or the like.
  • the transparent wall can provide the penetrating electromagnetic wave with special effects.
  • the present artificial magnetic material 11 does not require a permanent magnet for the production of an externa! bias magnetic field, and thus is suitable for applications to wide-area transparent bodies.
  • the present artificial magnetic material possesses non-reciprocal properties without any ferrite and permanent magnet.
  • the non-reciprocal devices previously described using the present artificial magnetic material can be miniaturized and their weight can be reduced as much as possible, since a permanent magnet for a bias magnetic field is. not needed.
  • the operation frequency can be easily increased, since no strong bias magnetic field is required to increase the operation frequency.
  • the present artificial magnetic material does not contain rare-earth elements, which are indispensable constituents of ferrites and permanent magnets. Because the present artificial magnetic material is independent of rare-earth metals, various applications in various fields are enabled.
  • the present artificial magnetic material is suitable for wide-area reflecting walls and transparent wails as it does not require a permanent magnet for the production of an external bias magnetic field.
  • the gyro resonator constituting the artificial magnetic material is formed of a single split ring shaped conductor pattern, but it may be formed from double conductor patterns similar to a conventional split-ring resonator. In that particular embodiment, the FET and other components would be disposed on each split ring shaped conductor pattern. Although in the previously discussed embodiments the FET is used as the unidirectional component, any other similar type of amplifier may be used as unidirectional component. However, an amplifier with variable gain is preferred.
  • the present artificial magnetic material possesses non-reciprocal properties without any ferrite and permanent magnet.
  • the non-reciprocal devices, which comprise the present artificial magnetic material can be miniaturized and their weight can be reduced as much as possible, since a permanent magnet for a bias magnetic field is not needed. In addition, their operation frequency can be easily increased.
  • the present artificial magnetic material is independent of rare-earth metals, various applications for various fields are enabled.

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Abstract

The present disclosure provides an artificial magnetic material which exhibits properties which are nearly equivalent to the gyromagnetic properties of ferrite materials without the application of a bias magnetic Field. In addition, the present disclosure provides some applications (e.g. devices) of this artificial magnetic material. The artificial magnetic material comprises a conductor pattern, which is ring-shaped with a gap; and a unidirectional component, which transmits a signal unidirectionaly, and which is inserted in the gap.

Description

ARTIFICIAL MAGNETIC MATERIAL, ARTIFICIAL MAGNETIC DEVICE, ARTIFICIAL MAGNETIC MATERIAL REFLECTING WALL AND ARTIFICIAL MAGNETIC MATERIAL
TRANSPARENT WALL
Technical Field
[0001] The present disclosure relates to an artificial magnetic material which exhibits properties nearly equivalent to gyromagnetic properties of ferrite materials, and more particularly to an artificial magnetic material which exhibits non-reciprocal properties nearly equivalent to gyromagnetic properties without application of a bias magnetic field. In addition, the present disclosure relates to applications (e.g. devices) of the present artificial magnetic material.
Background
[0002] Devices operating in the frequency region of microwave or the like can be classified into reciprocal devices and non-reciprocal devices. A reciprocal device is a network component that satisfies the reciprocity theorem and its scattering matrix corresponds to a symmetric matrix, A non-reciprocal device does not satisfy the reciprocity theorem and its scattering matrix is not a symmetric matrix. Isolators and circulators are representative non-reciprocal devices, which are widely used in microwave and millimeter wave systems to achieve stabilization and multifunction.
[0003] Conventionally, magnetic materials, such as ferrites, are used to realize the non- reciprocity of the non-reciprocal devices. The magnetic moment of electron spin, which determines the magnetic properties of a ferrite, starts precession when an external magnetic field is applied to the ferrite. This precession of the magnetic moment yields the magnetic gyrotropy of ferrites. The non-reciprocity of non-reciprocal devices is caused by the magnetic gyrotropy.
[0004] On the other hand, split-ring resonator has been studied in the research field of artificial materials, such as metamaterials. A metamaterial is an artificial material that consists of small metallic and dielectric particles which are periodically aligned in space, with periodicity much smaller than the wavelength. A metamaterial exhibits properties that cannot be found in natural materials.
[0005] In international patent application publication number WO2008/028010, an artificial magnetic material consisting of split-ring resonators is disclosed as a prior art, and another artificial magnetic material consisting of a pair of conductors facing each other across a dielectric material is disclosed. In international patent application publication number WO20O6/070036, a band-pass filter which uses split-ring resonators is disclosed. These structures differ from the split-ring resonator structures used in previous metamaterials. In previous metamaterials, the split rings were used to provide negative permeability via a fixed magnetic moment perpendicular to the plane of the ring.
[0006] These split-ring resonators exhibit a unique property of negative permeability, but cannot provide non-reciprocity. Therefore, split-ring resonators can only be used for the implementation of reciprocal devices. Non-reciprocal devices cannot be realized with split- ring resonators.
[0007] Non-reciprocal devices which use ferrite materials require a permanent magnet for the production of an external bias magnetic field. This requirement for an external magnetic field has set limits on the applicability of ferrite-based devices. The existence of a bulky permanent magnet prevents size miniaturization. In addition, increasing the operation frequency of the device needs a stronger magnet because the operation frequency of the ferrite device is proportional to the intensity of the bias magnetic field. These limitations prevent the miniaturization of a device, and make it difficult to realize even higher frequency (millimeter and tera-hertz wave) operation.
[0008] In some cases, the biasing requirement completely presents application. For example, assume a non-reciprocal boundary which uses the non-reciprocal properties of a ferrite medium requiring a bias magnetic field perpendicular to the boundary. In this case, the permanent magnet pair, which has to be put in front and back of the boundary, disturbs any wave approaching the ferrite surface. As a result, the non-reciprocal boundary by conventional ferrite material becomes impossible.
[0009] Rare-earth metals are indispensable constituents of ferrite materials and strong permanent magnets. The total amount of the deposits of rare-earth metals in the earth is very small, and the production is limited to very few specified countries and areas. . Therefore, an alternative technology independent of rare-earth metals is extensively required.
Summary
[0010] It is therefore an object of the present disclosure to provide an artificial magnetic material which exhibits non-reciprocal properties which are nearly equivalent to gyromagnetic properties without application of a bias magnetic field. Moreover, it is an object of the present invention to provide some applications (e.g. devices) of this artificial magnetic material.
[0011] To achieve this object, an artificial magnetic material according to the present disclosure comprises: a conductor pattern, which is ring-shaped with a gap; and a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap.
[0012] Further, the artificial magnetic material described above may further comprise: a planar back side conductor, which is in parallel with a plane which includes the conductor pattern.
[0013] Further, in the artificial magnetic material described above, a pair of the conductor patterns may be disposed parallel with each other, and planes which include one of the conductor patterns are in parallel with each other.
[0014] Further, in the artificial magnetic material described above, the unidirectional component preferably is a variable gain amplifier.
[0015] Further, in the artificial magnetic material described above, the unidirectional component preferably is a field effect transistor.
[0016] Further, an artificial magnetic material device according to the present disclosure comprises: a planar substrate comprising an insulating material; a conductor pattern, which is ring-shaped with a gap, and which is disposed on a front surface of the substrate; a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap; a transmission line, which is disposed on the front surface of the substrate; a planar back side conductor, which is disposed on a rear surface of the substrate; an input port, which inputs a signal to the transmission line; and an output port, which outputs a signal from the transmission line.
[0017] Further, an artificial magnetic material device according to the present disclosure comprises: a planar substrate comprising an insulating material; a conductor pattern, which is ring-shaped with a gap, and which is disposed on a front surface of the substrate; a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap; a planar back side conductor, which is disposed on a rear surface of the substrate; an input port which radiates an electromagnetic wave to a front side of the substrate; and an output port which outputs an electromagnetic wave reflected by the substrate. [0018] Further, an artificial magnetic material device according to the present disclosure comprises: a planar substrate comprising an insulating material; a pair of conductor patterns, which are ring-shaped with a gap, and which are disposed parallel with each other on a front surface and a rear surface of the substrate; a unidirectional component, which transmits a signal unidirectionally to a single rotational direction, and which is inserted in the gap of each conductor pattern; an input port, which radiates an electromagnetic wave to the front side or the rear side of the substrate; and an output port, which outputs an electromagnetic wave penetrating through the substrate.
[0019] Further, in the artificial magnetic material device described above, the unidirectional component preferably is a variable gain amplifier.
[0020] Further, in the artificial magnetic material device described above, the unidirectional component preferably is a field effect transistor.
[0021] Further, an artificial magnetic material wall that reflects an electromagnetic wave according to the present disclosure comprises: a planar substrate comprising an insulating material; a conductor pattern, which is ring-shaped with a gap, and which is disposed on a front surface of the substrate; a unidirectional component, which transmits a signal unidirectionally, and which is inserted in the gap; and a planar back side conductor, which is disposed on a rear surface of the substrate, wherein the front surface of the substrate is capable of reflecting an electromagnetic wave.
[0022] Further, in the artificial, magnetic materia! reflecting wall described above, the unidirectional component preferably is a variable gain amplifier.
[0023] Further, in the artificial magnetic material reflecting wall described above, the unidirectional component preferably is a field effect transistor,
[0024] Further, an artificial magnetic material wall that is transparent with an electromagnetic wave according to the present disclosure comprises: a planar substrate comprising an insulating material; a pair of conductor patterns, which are ring-shaped with a gap, and which are disposed parallel with each other on a front surface and a rear surface of the substrate; and a unidirectional component, which transmits a signal unidirectionally to the single rotational direction, and which is inserted in the gap of each conductor pattern, wherein the substrate is transparent with an electromagnetic wave. [0025] Further, in the artificial magnetic material transparent wall described above, the unidirectional component preferably is a variable gain amplifier.
[0026] Further, in the artificial magnetic material transparent wall described above, the unidirectional component preferably is a field effect transistor.
Description of Drawings
[0027] Fig. 1 is a schematic representation of a gyro-resonator 1, which is a constituent of the artificial magnetic material according to the present disclosure.
[0028] Fig. 2 is a schematic representation of an equivalent circuit of a gap portion of the gyro resonator 1.
[0029] Fig. 3 is a perspective view showing an external schematic representation of the gyro resonator 1.
[0030] Fig. 4 is a perspective view showing an external schematic representation of another type gyro resonator 12.
[0031] Fig. 5 is a schematic representation of an example device 6 for an evaluation using a plurality of gyro resonators 1.
[0032] Fig. 6 is a graph showing measured results, proving non-reciprocity of the device 6 of Figure 5.
[0033] Fig. 7 is a perspective view showing a schematic representation of a computing model of an artificial magnetic material.
[0034] Fig. 8 is a front view of the schematic representation of the computing model of the artificial magnetic material of Figure 7.
[0035] Fig. 9 is a plan view of the schematic representation of the computing model of the artificial magnetic material of Figure 7.
[0036] Fig. 10 is a graph showing an intensity distribution of an electric field in the artificial magnetic material. [0037] Fig. 11 is a schematic representation of a circulator 7 comprising the present artificial magnetic material of Figure 7.
[0038] Fig. 12 is a graph showing measured results, which indicate the property of the circulator 7.
[0039] Fig. 13 is a graph showing measured results, which demonstrate the non- reciprocal property of the circulator 7
[0040] Fig. 14 is a graph showing measured results, which demonstrate the non- reciprocal property of the circulator 7.
[00411 Fi9- 15 is a schematic representation of a transparent wall comprising the present artificial magnetic material.
[0042] Figs. 16 (a - e) are schematic representations showing various applications of the present artificial magnetic material..
[0043] Fig. 17 is a schematic representation of a conventional split-ring resonator. Description of Embodiments
[0044] The artificial magnetic material according to the present disclosure possesses non-reciprocal properties without any ferrite and permanent magnet. Any non-reciprocal device which uses the present artificial magnetic material can be miniaturized and its weight can be reduced as much as possible, since a permanent magnet for a bias magnetic field is not needed. In addition, the operating frequency can be easily increased, since no strong bias magnetic field is required to increase the operation frequency.
[0045] Further, the artificial magnetic material according to the present disclosure does not contain rare-earth elements, which are indispensable constituents of ferrites and permanent magnets. Because the artificial magnetic material is independent of rare-earth metals, various applications for various fields are enabled. The artificial magnetic material is suitable for wide-area reflecting walls and transparent walls because it does not require a permanent magnet for the production of an external bias magnetic field.
[0046] The present disclosure provides an artificial magnetic material which exhibits non- reciprocity to realize non-reciprocal components. First, a split-ring resonator, used for the realization of a conventional artificial magnetic material, will be explained. The split-ring resonator is widely studied in the context of artificial materials called metamaterials. A metamateriai is an artificial material that consists of small metallic and dielectric particles, spatially aligned according to a periodic lattice with periodicity much smaller than the wavelength. A metamateriai exhibits properties that cannot be observed in natural materials. For example, an artificial magnetic material which exhibits negative permeability can be realized by utilizing the split-ring resonator.
[0047J Fig. 17 schematically depicts a conventional split-ring resonator. The split ring shaped conductor patterns of 91 and Θ2 are disposed to form a double ring structure 9. Conductor patterns 91 and 92 allow both rightward and leftward electromagnetic wave propagation as shown by arrows. At a resonance frequency, superposition of these two waves form a standing wave along the double ring structure 9. A unique property, e.g. negative permeability, is observed near the resonance frequency,
[0048] The split-ring resonator 9 exhibits the unique property of negative permeability, but it does not exhibit non-reciprocity. Therefore, the split-ring resonator can be used only for the realization of reciprocal devices. Non-reciprocal devices cannot be realized with split- ring resonators.
[0049] By using ferrite material, non-reciprocal devices can be realized. The origin of the non-reciprocity is the magnetic gyrotropy of ferrites as described above, in a ferrite to which the external magnetic field is applied, the precession of the magnetic moment of electron spin happens in one direction and this fact leads to non-reciprocity.
[0050] Considering the above fact about ferrites, the gyro resonator 1 shown in Fig. 1 has been developed. It is designed so as to achieve a response equivalent to a gyrotropic response of ferrite materials. The constitution of the gyro resonator 1 will now be described with reference to Fig. 1. The split ring shaped (C-character shaped) conductor pattern 2 is disposed on a front side surface (the upper surface) of a substrate 0 of an insulator (dielectric). A backside surface (a lower surface) of the substrate 10 is totally covered by a conductor, which is named a backside conductor 21 (Fig. 3). These conductors are typically made of metal, but they can also be made of any other conducting material.
[0051] A field effect transistor (FET) 3 is disposed in a gap of the conductor pattern . One edge of the conductor pattern 2 is connected to a drain terminal of FET 3, and another edge is connected to a gate terminal of FET 3 through a capacitor 4. A source terminal of FET 3 is connected to the backside conductor 21 on the lower surface of the substrate through a hole. The FET 3 has two source terminate, both connected to the backside conductor 21. A direct-current (DC) bias voltage VDD is applied to the drain terminal of FET 3 through a meander line 5.
[0052] In the present gyro resonator 1, the FET 3 operates as a unidirectional signal component from the gate to the drain terminal. Because of the functioning of the FET 3, an electromagnetic wave oan propagate only in the arrow direction, and it cannot propagate in reverse direction. Therefore, the resonance of the gyro resonator 1 is formed by a traveling wave, and not a standing wave.
[0053] Fig. 2 is a schematic representation of an equivalent circuit of the gap portion of the gyro resonator 1 , One edge of the conductor pattern 2 is connected to the drain terminal of the FET 3, and the other edge is connected to the gate terminal of the FET 3 through a capacitor 4. In the conductor pattern 2, a traveling wave propagates toward the direction shown by arrows. The source terminal of the FET 3 is connected to a ground conductor, and the DC bias voltage VDD is applied to the drain terminal of the FET 3 through the meander line 5. The meander line 5 can be composed for example as a series circuit of an inductor L and a resistor R.
[0054] In another alternative, the meander line 5 may be made by a thin line pattern so that the characteristic impedance of the line is much larger than the corresponding of the conductor pattern 2. The large difference of the impedance provides the large impedance mismatch, which prevents a generated RF signal from leaking to the meander line 5. The meander shape produces even a larger inductance. As a result, the traveling wave in the conductor pattern 2 does not enter the meander line 5, and the power supply is decoupled from the gyro resonator 1.
[0055] In a particular embodiment of the gyro resonator 1 as shown in Fig. 1, the following configuration parameters were applied: conductor pattern 2 of 2.0 mm line width, meander line 5 of 0.3 mm line width, capacitor 4 of 1 pF capacitance, and a Renesus 3210S01 by Electronics Corporation was used as the FET 3. The circumference of the conductor pattern 2 corresponded to a half wavelength at the operation frequency. In this particular embodiment, the conductor pattern 2 and the FET 3 provided a 180-degree phase shift each, and, as a result, a traveling wave resonance occured in the gyro resonator 1. In another example, with a certterline of the conductor pattern 2 forming a circle of 9.3 mm diameter, the resonance frequency of the gyro resonator was 6.7 GHz.
[0056] It should be noted that the gain of the FET 3 must be within a range in which the gyro resonator 1 does not oscillate. Assuming that the gain of the FET is represented by A and that the attenuation coefficient of the conductor pattern 2 is represented by B, there are three cases of operation for the gyro resonator 1. If A*B > 1 , the gyro resonator 1 starts oscillating. If A*B = 1, the gyro resonator 1 operates as a loss-less resonator. If A*B < 1 , the gyro resonator 1 operates as a lossy resonator. Therefore the gain of FET 3 must be tuned so that A*B is less or equal to unity. Specifically, the A*B = 1 case yields a characteristic equivalent to an ideal loss-less ferrite.
[0057] The gain of FET 3 can be easily controlled by varying the DC bias voltage VDD, which is provided by a DC power source. For the particular embodiment where the FET 3 was a:NE3210S01 , the DC bias voltage VDD was set much lower than fi e rated value (4.0 V) to decrease the gain much less than under normal use. More particularly, in that embodiment where the FET used was a NE3210S01, the DC bias voltage VDD was driven at less or equal to 0.2 V.
[0058] Fig. 3 is a perspective view showing an external schematic representation of the gyro resonator 1. The split ring shaped (C-character shaped) conductor pattern 2 is disposed on the front side surface of the substrate 10 of insulator. The backside surface of the substrate 10 is totally covered by the backside conductor 21. The FET 3, and other components, which operate as a unidirectional component, are shown in simplified expression. An electromagnetic wave generated thereby propagates only in the arrow direction, and cannot propagate in reverse direction. Therefore, the resonance of the gyro resonator 1 is formed by a traveling wave, and not a standing wave.
[0059] The embodiment of the gyro resonator 1 of Figure 3 with the backside conductor 21 shown In Fig. 3 is not the only possible embodiment. Another exemplary embodiment schematically shown in Fig. 4 can be realized, in this particular embodiment, the split ring shaped (C-character shaped) conductor pattern 2 is disposed on the front side surface of the substrate 10 of insulator, and a similar conductor pattern 2 is disposed on the backside surface of the substrate 10. The FET 3 and other components shown in simplified expression function as a unidirectional component. In that particular embodiment of the gyro resonator 12, the circuit shown in Fig. 1 is disposed in the gap portion of each conductor pattern 2.
[0060] In that particular embodiment, a unidirectional component is disposed in each conductor pattern 2 on front side and backside surfaces of the substrate 10 of the insulator. Resulting electromagnetic waves propagate in the single rotational direction, as indicated by the arrow. The resonance of the gyro resonator .12 is also formed by a traveling wave, and not a standing wave. [0061] The gyro resonator 12 shown in Fig. 4 is equivalent to the gyro resonator 1 shown in Fig. 3, considering the mirror image of the conductor pattern 2 by the backside conductor 21. If the size of the conductor pattern 2 of the gyro resonator 12 is equal to the gyro resonator 1, and if the interval between conductor patterns 2 on the front side and backside surfaces of the substrate 10 is twice the interval between the conductor pattern 2 and the backside conductor 21 in the gyro resonator 1, both electromagnetic fields in gyro resonators 1 and 2 are equivalent to each other, as are the resonance frequencies.
[0062] Thus the electromagnetic field in the gyro resonator 12 is equivalent to the electromagnetic field in the gyro resonator 1. But an electromagnetic wave cannot penetrate the gyro resonator 1 in thickness direction because of the backside conductor 21. Contrarily an electromagnetic wave can penetrate the gyro resonator 12 in thickness direction, which renders the gyro resonator 12 suitable for applications related to transparent walls and transparent type devices. The gyro resonator 1 is suitable for applications related to reflecting walls and reflecting type devices. Both embodiments of gyro resonators 1 and 12 exhibit non-reciprocity similar to the magnetic gyrotropy of ferrites, as will be described in detail below.
[0063] The electromagnetic field in the gyro resonator 12 shown in Fig. 4 is equivalent to the electromagnetic field in the gyro resonator 1 shown in Fig. 3 as described above. Analyses of electromagnetic fields in the gyro resonators 1 and 12 have revealed that unidirectional rotation of magnetic moment occur in both embodiments. This rotation of magnetic moment in gyro resonators 1 and 12 is a phenomenon similar to the precession of magnetic moment in ferrites. Thus, the gyro resonators 1 and 12 exhibit non-reciprocity similar to the magnetic gyrotropy of ferrites because of this rotation of magnetic moment.
[0064] An exemplary device 6 comprising multiple gyro resonators 1 has been built to examine the non-reciprocity provided by the gyro resonator 1. Fig. 5 shows a schematic representation of an exemplary device 6 for an evaluation using a plurality of gyro resonators 1. The examplary device 6 includes eight gyro resonators 1 disposed on an upper surface of a substrate of insulator (dielectric), A lower surface of the substrate is covered by a backside conductor, which plays the role of the ground. The same DC bias voltage VDD is applied to all the FETs of the gyro resonators 1. The DC bias voltage VDD is adjustable. The gyro resonators 1 are disposed so as to support a traveling wave in the same direction. In Fig. 5, the traveling wave, which is resonating, rotates clockwise on each conductor pattern 2. [0065] A transmission pattern 63, for example a microstrip line, is linearly formed so as to be close to all gyro resonators 1. The width of the transmission pattern 63 is the same 2.0 mm as the width of the conductor patterns 2. The transmission pattern 63 is not in contact with the conductor patterns 2, and a minimum interval of 0.1 mm separates the transmission pattern 63 and the patterns 2. A first port 61 and a second port 62 are disposed in both ends of the transmission pattern 63 as an input and an output ports of the examplary device 6. A shorting patch 64 is disposed on a lower side of a middle part of the transmission pattern 63. The shorting patch 64 connects one side of the transmission pattern 63 to the backside conductor (ground).
[0066] In general, the field distribution in a microstrip line on a non-gyrotropic dielectric substrate concentrates on both sides of a width of the transmission line irrespective of the propagation direction. The field distribution is symmetric with respect to the propagation direction. On the other hand, the electric field distribution of a microstrip line on a biased ferrite substrate concentrates on one side with respect to the propagation direction. For example, the intensity of the field takes a maximum value on the left side and a minimum one on the right side, as facing to the propagation direction.
[0067] Assuming that the gyro resonator 1 in the examplary device 6 provides non- reciprocity similar to ferrites, the electromagnetic field should concentrate on one side with respect to the propagation direction. This displacement of the electromagnetic field leads to a difference in the transmissivity of a propagating wave from the first port 61 to the second port 62 and from the second port 62 to the first port 61. This difference is due to the fact that the shorting patch 64 to the ground is disposed on one side of the transmission pattern 63.
[0068] Fig. 6 is a graph showing the measured transmission characteristics of the exemplary device 6, which demonstrate non-reciprocity. For this measurement, the DC bias voltage VDD was set at 0.15 V. The vertical axis in the graph of Fig. 6 corresponds to transmission coefficients S2i and S12 in dB, and the horizontal axis in the graph corresponds to the frequency in GHz. The transmission coefficient S21 corresponds to the transmissivity from the first port 61 to the second port 62, and the transmission coefficient S12 corresponds to the transmissivity from the second port 62 to the first port 61. The thick line in the graph corresponds to the measured transmission coefficient S21, and the thin line in the graph corresponds to the measured transmission coefficient S12. As shown in Fig. 6, the transmission coefficients S2i and S12 have different values from 6.7 GHz to 6.8 GHz in frequency. Therefore, the examplary device 6 operates as a non-reciprocal device, and the artificial magnetic material consisting of the gyro resonator 1 provides non- reciprocity.
[0069] A significant difference between the transmission coefficients S2i and Si2 in the examplary device 6 is not measured when the gyro resonator 1 is deactivated by setting the DC bias voltage VDD - 0 V. The response of the examplary device Θ becomes very unstable when the DC bias voltage VDD is set to 0.22 V, voltage at which the gyro resonator 1 begins to oscillate.
[0070] Further, a device for comparison similar to the examplary device 6, but without the shorting patch 64 to the ground, has been made to examine the non-reciprocity. This configuration of the device for comparison does not exhibit a significant difference between transmission coefficients S2 and S12- Therefore, the shorting patch 64 to the ground causes the non-reciprocity shown in Fig. 6. This fact shows evidence of that the electromagnetic field of a propagating wave along the transmission pattern 63 is concentrated on one side.
[0070] Next, the properties of the artificial magnetic material has been confirmed by computations. A computing model of the artificial magnetic material is shown in Fig. 7 to Fig. 9. Fig. 7 is a perspective view showing the configuration of the computing model of the artificial magnetic material. Fig. 8 is the front view of the computing model. Fig. 9 is the plan view of the computing model. Directions of coordinate axes are shown in Fig. 7. The origin of the coordinates is positioned to the right and lower corner of the computing model. Thus the origin of the coordinates is the position shown in Fig. 8 and Fig. 9. The coordinates in Fig. 7 only show directions of coordinate axes.
[0071] The computing model of the artificial magnetic material is represented by a rectangular parallelepiped in which x direction size is a, y direction size is a and z direction size is 2c. The lower half part (the region of 0 < z <= c) of the rectangular parallelepiped is a substrate of insulator (dielectric). Two split ring shaped conductor patterns are disposed on a center plane (the plane of z = c). Each conductor pattern constitutes a gyro resonator. The upper half part (the region of c < z < 2c) of the rectangular parallelepiped is a vacuum space. Perfect electric conductor (electric wall) is set as a boundary condition on the upper surface (the plane of z■ 2c) and on the lower surface (the plane of z = 0) of the rectangular parallelepiped. Perfect magnetic conductor (magnetic wall) is set as a boundary condition on the left side surface (the plane of y = b) and on the right side surface (the plane of y = 0) of the rectangular parallelepiped.
[0072] The front surface (the plane of x = 0) is first port P1 to input and output an electromagnetic wave. The backside surface (the plane of x = a) is second port P2 to input and output an electromagnetic wave. In this computing model of the artificial magnetic material, the intensity distribution of the electric field of an electromagnetic wave propagating from first port P1 to second port P2 and from second port P2 to first port P1 has been calculated by a numerical analysis. Shown in Fig, 8, the electric field of the propagating electromagnetic wave lies to z direction. The numerical analysis is performed by a computer software which executes an electromagnetic field simulation performed in accordance with a finite element method.
[0073] Fig. 10 is a graph showing an intensity distribution of the z-direction electric field Ez in the artificial magnetic material. The intensity distribution of the electric field E2 is calculated on half depth plane (the plane of x = a/2) of the rectangular parallelepiped. The horizontal axis in the graph of Fig. 10 corresponds to the coordinate of y axis, and the vertical axis corresponds to the intensity of the electric field Ez. The thick line in the graph corresponds to the intensity distribution of the electric field Ez of an electromagnetic wave propagating from first port P1 to second port P2, and the thin line in the graph corresponds to the intensity distribution of the electric field Ez of an electromagnetic wave propagating from second port P2 to first port P1. The graph shows that the electric field distribution concentrates on one side , and that the electric field distribution concentrates on an opposite side when the electromagnetic wave propagates to the reverse direction. Thus the artificial magnetic material provides non-reciprocity.
[0074] These above demonstrate that the gyro resonators 1 and 12 exhibit non- reciprocity in the same way as a ferrite medium does. In other words, the artificial magnetic material based on gyro resonators 1 and 2 can be used as a substitute to ferrite medium. Thus almost every conventional non-reciprocal device using ferrites can be replaced by the present artificial magnetic material.
[0075] Fig. 11 is a schematic representation of an example of a circulator 7 utilizing the previously described artificial magnetic material. The circulator 7 is formed on the upper surface of a dielectric substrate of insulator, and the backside of the substrate is covered with a ground conductor. The circulator 7 has three input and output ports as first port 71 , second port 72 and third port 73. Three transmission lines are formed from each port to a circular conductor disposed on the center of the dielectric substrate. Six gyro resonators 1 are disposed closely to transmission lines. It has been confirmed that the circulator 7 exhibits general circulator properties when the circulator 7 is operated with the application of an appropriate DC bias voltage VDD.
[0076] Fig. 12 to Fig. 14 are graphs snowing measured results, demonstrating the property of the circulator 7. The vertical axis in the graph of Fig. 12 corresponds to the transmission coefficients Si2 and S2i in dB, and the horizontal axis in the graph corresponds to the frequency in GHz. The transmission coefficient S21 corresponds to the transmissivity from the first port 71 to the second port 72, and the transmission coefficient S12 corresponds to the transmissivity from the second port 72 to the first port 71. The thick line in the graph corresponds to the measured transmission coefficient S2i, and the thin line in the graph corresponds to the measured transmission coefficient S12.
[0077] The vertical axis in the graph of Fig. 13 corresponds to the transmission coefficients S23 and S32 in dB, and the horizontal axis in the graph corresponds to the frequency in GHz. The transmission coefficient S32 corresponds to the transmissivity from the second port 72 to the third port 73, and the transmission coefficient S23 corresponds to the transmissivity from the third port 73 to the second port 72. The thick line in the graph corresponds to the measured transmission coefficient S32, and the thin line in the graph corresponds to the measured transmission coefficient S23-
[0078] The vertical axis in the graph of Fig. 14 corresponds to the transmission coefficients and S31 in dB, and the horizontal axis in the graph corresponds to the frequency in GHz. The transmission coefficient S13 corresponds to the transmissivity from the third port 73 to the first port 7 , and the transmission coefficient S31 corresponds to the transmissivity from the first port 71 to the third port 73. The thick line in the graph corresponds to the measured transmission coefficient S13l and the thin line in the graph corresponds to the measured transmission coefficient S31. As shown in Fig. 12 to Fig. 14, each transmissivity of different transmission direction has different values from 7.0 GHz to 8.0 GHz in frequency. Therefore, the circulator 7 exhibits the property of a non-reciprocal device.
[0079] Next, the example of a transparent wall constituted by gyro resonators 12 shown in Fig. 4 will now be described. Fig. 15 is a schematic representation of a transparent wall comprising the artificial magnetic material 11. The split ring shaped conductor patterns are formed on the front side and backside surfaces of a substrate of insulator. A plurality of gyro resonators uniformly disposed on the substrate constitute the artificial magnetic material 11 , An electromagnetic wave can penetrate the artificial magnetic material 11 in thickness direction. This embodiment of the artificial magnetic material 11 is suitable for applications to transparent walls and transparent type devices.
[0080] The electromagnetic field of an electromagnetic wave penetrating the artificial magnetic material 11 has been calculated by a numerical analysis. The numerical analysis was performed by a computer software which executed an electromagnetic field simulation performed in accordance with a finite element method. As a result, it was confirmed that the plane of polarization of the electromagnetic wave rotates when the electromagnetic wave penetrates the artificial magnetic material. This phenomenon is so- called Faraday rotation, and it is the same one which occurs in a biased ferrite. Thus the gyro resonator 12 and the artificial magnetic material 11 exhibit non-reciprocity similar to ferrites.
[0081] From the above computations, it was confirmed that the gyro resonator 1 formed on the dielectric substrate operates as an artificial magnetic material, and that it can be used as a substitute of a biased ferrite medium. The bias magnetic field is indispensable for the ferrite medium, but it is unnecessary for the artificial magnetic material made of the gyro resonator. The non-necessity for a bias magnetic field results in the elimination of the permanent magnets from the non-reciprocal devices. This fact enables the miniaturization of the device. Moreover, the present gyro resonator and resulting artificial magnetic material do not need high bias magnetic field for high frequency operation, enabling the easy increase in the operation frequency. The present artificial magnetic material does not contain any rare-earth materials, which are indispensable constituents of ferrites and permanent magnets, providing indicates that promising substitution of ferrites which strongly depend on valuable rare-earth materials.
[0082] Examples of applications of the present artificial magnetic material will now be described. Fig. 6 is a schematic representation representing various applications of the present artificial magnetic material. Fig. 16(a) schematically depict an application of a transmission line type device which uses the present artificial magnetic material. The artificial magnetic material 11 is an insulator (dielectric) substrate on which gyro resonators 1 are disposed at proper positions. The transmission line type device has four input and output ports 81 - 84, which are connected with the transmission line network 85 formed on the artificial magnetic material 11. In the same manner, an arbitrary non- reciprocal device can be constituted. The number of input and output ports is not limited to four, but it is arbitrary.
[0083] Fig. 16(b) is a schematic representation of a transparent type device which uses the present artificial magnetic material. The artificial magnetic material 1 is an insulator (dielectric) substrate on which gyro resonators 12 are disposed at proper positions, and it may be one shown in Fig. 15 for example. The electromagnetic wave from the input and output port 81 penetrates the artificial magnetic material 1, and it is transferred to the input and output port 82. This transparent type device also is a non-reciprocal device because of non-reciprocity of the artificial magnetic material 11. [0084] Fig. 16(c) shows a schematic representation of a reflecting type device which uses the present artificial magnetic material. The artiftciai magnetic material 11 comprises an insulator (dielectric) substrate on which gyro resonators 1 are disposed at proper positions. The electromagnetic wave from the input and output port 81 is reflected on the surface of the artificial magnetic material 11, and it is transferred to the input and output port 82. This transparent type device also is a non-reciprocal device because of non- reciprocity of the artificial magnetic material 11.
[0085] Fig. 16(d) schematically depicts the use of the present artificial magnetic material 11 as a reflecting wall. The artificial magnetic material 11 comrpises an insulator (dielectric) substrate on which gyro resonators 1 are disposed at proper positions. The reflecting wall utilizing the artificial magnetic material 11 can be used as outer walls of buildings and surfaces of airplanes or the like. The polarization of the electromagnetic wave reflected by the artificial magnetic material 11 can be rotated non- reciprocally. Contrary to ferrites, the artificial magnetic material 11 does not require a permanent magnet for the production of an external bias magnetic field, it is thus suitable for applications related to wide-area reflecting walls.
[0086] Fig. 16(e) schematically depicts the use of the artificial magnetic material 1 as a transparent wall. The artificial magnetic material 11 comprises an insulator (dielectric) substrate on which gyro resonators 12 are disposed at proper positions, for example as shown in Fig. 15. The transparent wall utilizing the present artificial magnetic material 1 can be used as windowpanes of buildings and transparent windows of airplanes or the like. The transparent wall can provide the penetrating electromagnetic wave with special effects. Contrary to ferrites, the present artificial magnetic material 11 does not require a permanent magnet for the production of an externa! bias magnetic field, and thus is suitable for applications to wide-area transparent bodies.
[0087] The present artificial magnetic material possesses non-reciprocal properties without any ferrite and permanent magnet. The non-reciprocal devices previously described using the present artificial magnetic material can be miniaturized and their weight can be reduced as much as possible, since a permanent magnet for a bias magnetic field is. not needed. In addition, the operation frequency can be easily increased, since no strong bias magnetic field is required to increase the operation frequency.
[0088] Further, the present artificial magnetic material does not contain rare-earth elements, which are indispensable constituents of ferrites and permanent magnets. Because the present artificial magnetic material is independent of rare-earth metals, various applications in various fields are enabled. The present artificial magnetic material is suitable for wide-area reflecting walls and transparent wails as it does not require a permanent magnet for the production of an external bias magnetic field.
[0089] Although in the above embodiments, the gyro resonator constituting the artificial magnetic material is formed of a single split ring shaped conductor pattern, but it may be formed from double conductor patterns similar to a conventional split-ring resonator. In that particular embodiment, the FET and other components would be disposed on each split ring shaped conductor pattern. Although in the previously discussed embodiments the FET is used as the unidirectional component, any other similar type of amplifier may be used as unidirectional component. However, an amplifier with variable gain is preferred.
[0090] The present artificial magnetic material possesses non-reciprocal properties without any ferrite and permanent magnet. The non-reciprocal devices, which comprise the present artificial magnetic material can be miniaturized and their weight can be reduced as much as possible, since a permanent magnet for a bias magnetic field is not needed. In addition, their operation frequency can be easily increased. The present artificial magnetic material is independent of rare-earth metals, various applications for various fields are enabled.

Claims

1. An artificial magnetic material comprising:
a ring-shaped conductor pattern, with a gap; and
a unidirectional component inserted in said gap, the unidirectional component being adapted for transmitting a signal unidirectionally.
2. The artificial magnetic material according to claim 1, further comprising a planar back side conductor parallel with a plane including said conductor pattern.
3. The artificial magnetic material according to claim 1 , wherein a pair of said conductor patterns are respectively disposed on parallel planes.
4. The artificial magnetic material according to any of claims 1 to 3, wherein said unidirectional component is a variable gain amplifier.
5. The artificial magnetic material according to claim 4, wherein said unidirectional component is a field effect transistor.
6. An artificial magnetic device comprising:
a planar substrate comprising an insulating material;
a ring-shaped conductor pattern with a gap, the ring-shaped conductor pattern being disposed on a front surface of said substrate
a unidirectional component inserted in said gap, the component being adapted for transmitting a signal unidirectionally;
a transmission line disposed on the front surface of said substrate;
a planar back side conductor disposed on a rear surface of said substrate;
an input port for inputing a signal to said transmission line; and
an output port for outpufing a signal from said transmission line,
7. An artificial magnetic device comprising:
a planar substrate comprising an insulating material;
a ring-shaped conductor pattern with a gap, the ring-shaped conductor pattern being disposed on a front surface of said substrate;
a unidirectional component inserted in said gap and adapted for transmiting a signal unidirectionally;
a planar back side conductor disposed on a rear surface of said substrate;
an input port for radiating an electromagnetic wave to a front side of said substrate; and an output port for outputing an electromagnetic wave reflected by said substrate.
8. An artificial magnetic materia! device comprising
a planar substrate comprising an insulating material;
a pair of ring-shaped conductor patterns with a gap, the pair of ring-shaped conductor patterns being disposed parallel with each other respectively on a front surface and a rear surface of said substrate;
a unidirectional component inserted in said gap of each conductor pattern fortransmiting a signal unidirectionally;
an input port for radiating an electromagnetic wave to a front side or a rear side of said substrate; and
an output port for outputing an electromagnetic wave penetrating through said substrate.
9. The artificial magnetic material device according to any of claims 6 to 8, wherein said unidirectional component is a variable gain amplifier.
10. The artificial magnetic material device according to claim 9, wherein said
unidirectional component is a field effect transistor.
1 . An artificial magnetic material wall for reflecting an electromagnetic wave, comprising: a planar substrate comprising an insulating material;
a ring-shaped conductor pattern with a gap, the ring-shaped conductor pattern being disposed on a front surface of said substrate;
a unidirectional component inserted in said gap fortransmiting a signal unidirectionally; and
a planar back side conductor is disposed on a rear surface of said substrate,
wherein the front surface of said substrate is capable of reflecting an electromagnetic wave.
12. The artificial magnetic material wall according to claim 11, wherein said unidirectional component is a variable gain amplifier.
13. The artificial magnetic material wall according to claim 12, wherein said unidirectional component is a field effect transistor.
1 . An artificial magnetic material wall transparent to an electromagnetic wave, comprising:
a planar substrate comprising an insulating material;
a pair of ring-shaped conductor patterns each having a gap, the pair of ring-shaped conductor patterns being respectively disposed parallel with each other on a front surface and a rear surface of said substrate; and
a unidirectional component inserted in said gap of each conductor pattern, the
unidirectional component transmiting a signal unidirectionally,
wherein said substrate is transparent to an electromagnetic wave.
15. The artificial magnetic material wall according to claim 14, wherein said unidirectional component is a variable gain amplifier.
16. The artificial magnetic material wall according to claim 15, wherein said unidirectional component is a field effect transistor.
PCT/CA2011/001422 2010-12-22 2011-12-22 Artificial magnetic material, artificial magnetic device, artificial magnetic material reflecting wall and artificial magnetic material transparent wall Ceased WO2012083441A1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2529211A (en) * 2014-08-13 2016-02-17 Bae Systems Plc Antenna structure
US9405136B2 (en) 2013-07-23 2016-08-02 Board Of Regents, The University Of Texas System Magnetic-free non-reciprocal devices exhibiting non-reciprocity through angular momentum biasing
JP2019515542A (en) * 2016-04-22 2019-06-06 テレフオンアクチーボラゲット エルエム エリクソン（パブル） Circulator device with two magnet-free circulators

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5688688B2 (en) 2012-06-12 2015-03-25 横河電機株式会社 Insulation circuit, insulation circuit characteristic adjustment system, insulation circuit shield device, and insulation circuit characteristic adjustment method
WO2019076437A1 (en) * 2017-10-16 2019-04-25 Centre National De La Recherche Scientifique Detection sensor with capturing cell having a high-electron-mobility transistor (hemt) and ring resonators

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
K. AYADIN ET AL.: "Capacitor loaded split ring resonators as tunable metamaterial components", JOURNAL OF APPLIED PHYSICS, vol. 101, 22 January 2007 (2007-01-22), pages 024911 *
PENCIU ET AL.: "Multi-gap individual and coupled split ring resonator structures", OPTICS EXPRESS, vol. 16, no. 22, 27 October 2008 (2008-10-27), pages 18131 - 18144 *
SHADRIVOV ET AL.: "Tunable split ring resonators for non linear negative-index metamaterials", OPTICS EXPRESS, vol. 14, no. 20, 2 October 2006 (2006-10-02), pages 9346 - 9348 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9405136B2 (en) 2013-07-23 2016-08-02 Board Of Regents, The University Of Texas System Magnetic-free non-reciprocal devices exhibiting non-reciprocity through angular momentum biasing
US9880403B2 (en) 2013-07-23 2018-01-30 Board Of Regents, The University Of Texas System Magnetic-free non-reciprocal devices exhibiting non-reciprocity through angular momentum biasing
GB2529211A (en) * 2014-08-13 2016-02-17 Bae Systems Plc Antenna structure
JP2019515542A (en) * 2016-04-22 2019-06-06 テレフオンアクチーボラゲット エルエム エリクソン（パブル） Circulator device with two magnet-free circulators

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