Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P3/00—Waveguides; Transmission lines of the waveguide type
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P3/00—Waveguides; Transmission lines of the waveguide type
  • H01P3/02—Waveguides; Transmission lines of the waveguide type with two longitudinal conductors
  • H01P3/08—Microstrips; Strip lines

Definitions

• Positive and negative permittivity media or positive and negative permeability media made of metamaterials, and waveguides that propagate surface waves using them
• the present invention relates to a positive / negative dielectric constant medium or positive / negative magnetic permeability medium made of a metamaterial, and a waveguide that propagates a surface wave using the medium.
• metamat- eiials in the sense that it exceeds the natural medium.
• the properties of metamaterials vary depending on the shape of the unit particles, the material, and their arrangement. Among them, metamaterials whose equivalent permittivity ⁇ and permeability are simultaneously negative are the electric field and It was named “Left-Handed Materials” because the magnetic field and wavenumber vector form a left-handed system.
• a normal medium in which the equivalent permittivity ⁇ and permeability ⁇ are simultaneously positive is called “Right-Handed Materials”.
• the regions related to the permittivity ⁇ and permeability and the medium can be classified into the media in the first quadrant to the fourth quadrant according to the positive and negative of the permittivity ⁇ and the positive and negative of the permeability.
• the “left-handed medium” is the presence of a wave called the pack word wave, in which the sign of the wave group velocity (velocity of energy propagation) and phase velocity (velocity of phase advance) are reversed.
• the pack word wave in which the sign of the wave group velocity (velocity of energy propagation) and phase velocity (velocity of phase advance) are reversed.
• it has unique properties such as amplification of evanescent waves that are exponentially decaying in the non-propagating region.
• surface waves propagate on the surface.
• the dielectric constant of the metal in the light region is negative
• surface waves called surface plasmons exist at the interface between air and dielectrics with a positive dielectric constant.
• a surface wave propagates to the boundary between a medium in which either one of permittivity ⁇ or permeability is negative and a medium in which both permittivity ⁇ and permeability are positive.
• Fig. 2 shows the state in which a surface wave propagates to the boundary between a medium with a negative permeability / and a medium with a positive permeability.
• the negative dielectric constant characteristics of metals in the light region and the negative magnetic permeability characteristics of magnetized ferrite are the properties of natural materials themselves, and the values of dielectric constant ⁇ and magnetic permeability can be freely designed. It is not possible. Therefore, the surface wave propagation frequency band determined by that value cannot be determined or designed freely.
• the negative dielectric constant characteristics of metals The surface plasmon is a phenomenon in the light region, and the transmission band of the surface wave magnetostatic wave of the ferrite is determined by the direction and magnitude of the applied DC magnetic field, but a realistic number T (Tesla) Even if a DC magnetic field is applied, the microwave region becomes the upper limit. Also, it was not easy to excite these surface plasmons and surface magnetostatic waves. Disclosure of the invention
• the present invention constitutes a medium having properties that are effectively necessary by arranging metals, dielectrics, magnetic materials, superconductors, semiconductors, and the like at intervals shorter than the wavelength used.
• the objective is to construct a negative dielectric medium or a negative permeability medium and to construct a waveguide that transmits the surface wave.
• the first invention of this application is to form a rectangular metal patch on the surface of a dielectric substrate, leaving a dielectric around, and a ground conductor on the entire back surface of the dielectric substrate.
• the value of permeability / can be freely designed, and when applied to a waveguide, the surface wave propagation frequency band determined by that value can be freely set. Can be determined or designed.
• a rectangular metal patch is formed on the surface of a dielectric substrate leaving a dielectric around it, and a unit cell having a structure having a ground conductor on the entire back surface of the dielectric substrate is formed.
• the negative permeability medium composed of the unit cell assembly different permeability can be obtained in different directions by changing the ratio of the length of the vertical and horizontal sides of the rectangular metal patch or the unit cell itself.
• a hexagonal metal patch is formed on the surface of a hexagonal dielectric substrate leaving a dielectric around it, and a ground conductor is formed on the entire back surface of the dielectric substrate.
• a negative permeability medium made of a metamaterial that forms a structural unit cell and is constituted by an assembly of the unit cells.
• a negative permeability medium consisting of a metamaterial with low anisotropy
• the value of permeability ⁇ can be designed freely.
• the surface wave determined by that value The propagation frequency band can be determined or designed freely.
• a metal strip is formed on the surface of a dielectric substrate, and a ground conductor is formed on the entire back surface of the dielectric substrate.
• the metal strip and the middle or middle of the metal strip are provided.
• dielectric constant ⁇ can be designed freely, and when applied to a waveguide, the surface wave propagation frequency band determined by that value can be freely set. Can be determined or designed.
• a hexagonal metal strip is formed on the surface of a hexagonal dielectric substrate to connect the middle of the hexagonal sides, and a ground conductor is formed on the entire back surface of the dielectric substrate.
• a unit cell composed of a metal strip on the surface of the dielectric substrate and a metal via connecting the metal strip to the ground conductor on the back side of the substrate from the middle or other than the middle,
• the metal strip on the surface of the substrate is a negative dielectric constant medium made of a metamaterial formed by connecting to a metal strip between adjacent cells.
• the metal strip shape symmetry, unit cell symmetry, and via position are changed.
• a medium with positive permeability and positive dielectric constant made of a metamaterial composed of multiple cells.
• the values of permeability ⁇ and permittivity ⁇ can be designed freely, and when applied to a waveguide, the values The surface wave propagation frequency band determined by can be determined or designed freely.
• the eighth invention of this application is the negative permeability medium made of the material of any one of the first to third inventions and the positive permeability made of the metamaterial of the seventh invention.
• the waveguide has a structure in which the rate medium is adjacent and opposed to each other, and a surface wave can propagate to the boundary between the two media.
• the waveguide according to claim 9 of the present invention of the present application is a negative dielectric constant medium made of the metamaterial according to any one of claims 4 to 6, and the metamaterial according to claim 7.
• the positive dielectric constant medium is an adjacent / opposite structure, and the surface wave can be propagated to the boundary between the two media.
• the wavelength in the waveguide is determined by the equivalent permittivity and permeability of these media.
• the wavelength in the waveguide is smaller than the wavelength in vacuum. It can be done.
• anisotropy can be controlled by designing unit cells. By controlling the anisotropy, it is possible to design devices with a higher degree of freedom using this medium. The invention's effect
• the present invention it is possible to make a waveguide that transmits a surface wave that operates even at various frequencies from a low frequency theoretically close to DC to THz.
• the wavelength in this waveguide is determined by the equivalent permittivity and permeability of these media. By designing these values, the wavelength in the waveguide can be made smaller than that in vacuum. By utilizing this wavelength shortening effect, it is possible to fabricate a small resonator and a small delay line.
• anisotropy can be controlled by designing unit cells. An anisotropic control allows more flexible device design using this medium.
• excitation of surface plasmons in the optical region must produce an excitation wave with a large wavenumber using a dielectric prism or grating. It is also used for surface magnetostatic wave excitation.
• a device for converting microwave band electromagnetic waves to magnetostatic waves, such as Lance Dusser, is required, but the surface wave mode of the medium of the present invention has good compatibility with planar circuits and is usually used for microstrip lines and the like. It can be easily excited from the planar circuit.
• Figure 1 shows the relationship between dielectric constant ⁇ , permeability / and medium.
• Figure 2 shows the propagation of normal surface waves.
• Figure 3 is a 2D surface wave transmission line model diagram.
• FIG. 4 is a schematic view of the periodic structure negative permeability medium of the present invention.
• FIG. 5 is an equivalent circuit of the unit cell constituting the negative permeability medium of the present invention.
• Figure 6 shows a unit cell of a medium with a positive dielectric constant and permeability.
• FIG. 9 is a conceptual diagram showing the boundary between the negative permeability medium and the positive permeability medium of the present invention.
• FIG. 8 is a dispersion relation diagram of the surface wave mode of the medium of the present invention.
• Figure 9 shows the electric field intensity distribution on the substrate surface of the short-circuited surface wave mode resonator.
• FIG. 10 is a hexagonal negative permeability medium unit cell and its medium configuration diagram.
• Figure 11 is a schematic diagram of a negative dielectric constant medium.
• Figure 12 shows a negative dielectric constant medium unit cell and its equivalent circuit.
• Figure 13 shows the hexagonal negative permeability medium unit cell and the configuration of the negative permeability medium.
• the basic configuration of the present invention is a negative magnetic permeability medium as an example.
• Negative magnetic permeability medium (-negative medium) and positive magnetic permeability medium-positive medium) Surface waves propagate on the boundary of the combination of and.
• the equivalent circuit of the unit cell of each medium is shown on the right, and the circuit elements of this equivalent circuit have the circuit configuration shown in the table. Embodiments will be described below for each of a negative permeability medium and a negative dielectric constant medium.
• FIG. 4 shows a first embodiment of the present invention, which is a schematic diagram of a periodic structure negative permeability medium 1 made of a medium having a negative permeability (one negative medium) for a permeability medium (metamaterial). is there.
• FIG. 5A shows a unit cell 2 constituting the negative permeability medium 1 of FIG.
• a rectangular metal patch 4 is formed on the surface of the dielectric substrate 3 leaving a dielectric around it, and a ground conductor 5 is provided on the entire back surface of the substrate 3.
• Figure 5 (B) shows the equivalent circuit of this unit cell 2.
• This unit cell 2 has a capacitance C in series with the adjacent metal patch 4, and at the same time has a capacitance C ′ parallel to the ground plane on the back surface of the dielectric substrate 3.
• the parasitic inductance L must be considered in series, but this is usually small and can be ignored. It is proved that a medium having such a series capacitance C and a parallel capacitance C ′ within a range where the series inductance L can be ignored is equivalently a medium having negative permeability.
• Figure 6 shows the configuration of a unit cell 6 of a medium (ju—positive medium, ⁇ —positive medium) having a positive permeability and a positive dielectric constant.
• a medium ju—positive medium, ⁇ —positive medium
• This is an existing microstrip line, and has a two-dimensional structure in which a metal strip 7 is connected to the surface of the dielectric substrate 3 in all directions.
• the ground conductor 5 is disposed on the entire back surface of the substrate 3.
• FIG. 7 is a conceptual diagram showing the boundary of the combined medium of the negative permeability medium in FIG. 4 and the positive permeability medium composed of the unit cells 6 in FIG. 6 adjacent to each other on the left and right. For simplicity, if the periods of the negative permeability medium and the positive permeability medium are equal, this boundary itself also has a periodic structure.
• Figure 8 shows the calculation result of the dispersion relation of the surface wave propagating through this boundary obtained by 3D electromagnetic field simulation based on the finite element method for the boundary of the periodic structure of one period in It is fruit.
• the horizontal axis is the value obtained by normalizing the wave number /? Of this surface wave with / a (a is the length of one side of the unit cell, is the circumference), and the vertical axis is the frequency of the propagation surface wave.
• a is the length of one side of the unit cell, is the circumference
• the vertical axis is the frequency of the propagation surface wave.
• Fig. 9 shows the three-dimensional finite element of the electric field distribution on the substrate surface of a double-sided short-circuit type surface wave mode resonator constructed by short-circuiting metal walls at both ends against the boundary of 8 periods of the periodic structure in Fig. 7 It is a result of electromagnetic field simulation.
• the figure shows the electromagnetic field distribution for each of the resonance modes n 2 1, 2, and 3 with respect to the mode number. In either case, it can be seen that there is a surface wave where the electric field concentrates on the boundary.
• the surface patch does not need to be square, and can be any shape as long as it has a series capacitance.
• the unit cell itself need not be square. The more the unit cell shape is broken, the stronger the anisotropy is. In this way, anisotropy can be controlled.
• FIG. 10 shows a schematic diagram of the negative permeability medium of the second embodiment of the present invention.
• Figure 10 (A) shows an example of the structure of unit cell 2 of a hexagonal negative permeability medium. This is because the hexagonal metal patch 4 is applied to the surface of the hexagonal dielectric substrate 5. It is formed with a dielectric around it, and the back surface of the substrate 3 has a ground conductor 5 on the entire surface.
• FIG. 10 (B) is a negative permeability medium 1 configured by assembling the hexagonal unit cells 2 of FIG. 10 (A). By adopting such a configuration, the anisotropy of the unit cell 2 and the negative permeability medium 1 can be reduced.
• FIG. 11 shows a schematic diagram of a negative dielectric constant medium 11 1 according to a third embodiment of the present invention.
• the negative dielectric constant medium 11 is composed of a set of a plurality of unit cells 12.
• FIG. 12 (A) shows a rectangular unit cell 12 constituting the negative dielectric constant medium 11 shown in FIG.
• a metal strip 16 is formed on the surface of the dielectric substrate 13, and a ground conductor 15 is formed on the entire back surface of the dielectric substrate 13. It consists of this metal strip 16 and a metal via (through hole) 14 that connects it to the ground conductor 15 on the back side of the board from the middle or other than the middle.
• the metal strip 16 on the substrate surface is connected to the metal strip between adjacent cells.
• Figure 12 (B) is an equivalent circuit of this unit cell 12.
• the metal strip 16 on the surface has a series inductance L, and at the same time has an inductance L 'in parallel to the ground conductor 15 due to the via 14.
• there is a parasitic capacitance C to the ground conductor 15 but this is usually small and can be ignored.
• a medium having such a series inductance L and a parallel inductance L 'in a range where the parallel capacitance C is small can prove to be a medium having an equivalent negative dielectric constant.
• the anisotropy can be controlled by changing the symmetry of the shape of the metal strip 16, the symmetry of the unit cell 12, and the position of the via 14. That is, it is possible to have different dielectric constants for different directions.
• FIG. 13 shows a schematic diagram of a negative dielectric constant medium according to a fourth embodiment of the present invention.
• Fig. 13 ( ⁇ ) shows an example of the structure of unit cell 12 of hexagonal negative dielectric constant medium.
• FIG. 13 (B) is a negative dielectric constant medium 11 composed of the hexagonal unit cells 12 in FIG. 13 (A).
• the anisotropy of the unit cell 12 and the negative dielectric constant medium 1 1 1 can be made smaller than that of the square one. Even in this configuration, the anisotropy can be controlled by changing the symmetry of the shape of the metal strip 16, the symmetry of the unit cell 12, and the position of the peer 14. That is, it is possible to have different dielectric constants for different directions.
• the negative dielectric constant medium 11 shown in FIG. 13 obtained in this way and the positive dielectric constant medium 7 consisting of unit cells 6 having the same configuration as in FIG. With a medium combined adjacent to each other, a waveguide that propagates a surface wave at the boundary between the two media can be obtained.
• the present invention can be widely used as a circuit element that requires the characteristics of a negative dielectric constant medium or a negative magnetic permeability medium made of a metamaterial, and can form a waveguide that propagates a surface wave using them. It can be widely applied as a component of devices such as resonators, filters, and oscillators for ultra-compact communications.

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• 2005
  • 2005-03-02 JP JP2005057763A patent/JP3928055B2/ja not_active Expired - Lifetime
• 2006
  • 2006-02-27 WO PCT/JP2006/304186 patent/WO2006093302A1/ja not_active Ceased
  • 2006-02-27 US US11/817,552 patent/US7864114B2/en not_active Expired - Fee Related

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