CN103700948B - Double cantilever E types reversely nested LHM with adjustable cross metal wire structure - Google Patents

Abstract

A double cantilever E-type reverse nested left-hand material with an adjustable cross wire structure relates to a left-hand material. A double cantilever E-type reverse nested left hand material with adjustable cross wire construction is available. It is equipped with a dielectric substrate, a double cantilever E-shaped metal wire and a cross metal wire structure; the double cantilever E-shaped metal wire is reversely and symmetrically etched on one side of the dielectric substrate, and the middle arm of the staggered nested E-shaped structure is disconnected , the cross wire structure is arranged on the back side of the dielectric substrate. The length of each side of the double cantilever E-shaped structure of the left-hand material, the coupling degree of the two cantilever E-shaped metal wires, and the cross-structure orthogonal overlapping position are easy to control. By adjusting the geometric parameters of the unit, one or more left-hand frequency bands can be adjusted. control. When changing the incident wave direction and electric field polarization direction while keeping the magnetic field polarization direction unchanged, the left-handed characteristics of the array structure do not change, widen the incident angle of electromagnetic waves, and realize the left-handed characteristics when incident from two directions at the same time.

Description

Double cantilever E-type reverse nested left hand material with adjustable cross wire structure

technical field

The invention relates to a left-handed material, in particular to a double-cantilever E-type reverse-nested left-handed material with an adjustable cross wire structure that can realize incidence in two directions and controllable frequency characteristics.

Background technique

Left-handed material (left-handed metamaterials) is an artificial composite material with negative permittivity and negative magnetic permeability. It is a periodic distribution array structure originally proposed by the former Soviet physicist Mandelshtam in 1940. The periodic array structure etched on the dielectric substrate of the microwave circuit can cause the resonance of the electric field and the magnetic field in a certain frequency range, so that the equivalent permittivity and magnetic permeability of the structure exhibit negative values at the same time. The main characteristic of the left-handed material is that the phase velocity of the electromagnetic wave propagating in the left-handed material is opposite to the direction of the group velocity, and the energy propagation direction of the electromagnetic wave is opposite to the direction of the phase velocity. and satisfy the left-handed spiral relationship. In the 1990s, Pendry et al. (VG Veselago. The Electrodynamics of Substances with Simultanesously Negtive Value [J]. Soviet Physics. 1968, 10: 509-514) proposed a theoretical model composed of periodic metal wires, and deduced the negative dielectric constant frequency band of the structural model. According to Pendry's research, through the periodic arrangement of split resonant rings, that is, SRRs, the magnetic properties of the material can be negative in a certain frequency range. In 1996, he first proposed that the dielectric constant of thin metal wires arranged periodically will be negative when the incident frequency is lower than the plasma resonance frequency, and at the same time he gave an analytical model for calculating the effective dielectric constant. In 1999, his research group once again proposed that the periodically placed open-loop resonator array can exhibit the characteristics of negative magnetic permeability, and the model structure for calculating the magnetic permeability of SRR was given in the paper. In 2000, based on the average method (HsuYJ, HuangYC, LihJS.Electromagneticresonanceindeformedsplitringresonatorsoflefthandedmeta-materials[J].2003,258:161-166) as the theoretical basis, Smith proposed three kinds of effective permittivity and effective permeability of left-handed materials that can be directly calculated. The analysis of the negative refractive index of the left-handed material is analyzed by the method of the ratio, and the relationship between the negative refractive index of the left-handed material and the material permittivity and magnetic permeability is obtained. In 2006, the research by Xu et al. showed people the extraction technology of effective constitutive parameter tensor of SRR array (AntoniadesMA, EleftheriadesGV. In the process of quantity extraction, the equivalent circuit method can be used to describe the physical essence. In recent years, left-handed materials have been applied in many fields, including electromagnetics, optics, acoustics, electromagnetic stealth, communication, and medicine, and have become a research hotspot among scholars at home and abroad. In addition to the SRR structure, many structures have shown left-handed characteristics at a certain frequency point or frequency band, including spiral ring structure, dendritic structure, mushroom structure, double S structure, Z structure, etc. However, the left-handed materials of these structures can only achieve left-handed characteristics in a specific incident direction, so they lack the flexibility and diversity of applications.

Contents of the invention

The object of the present invention is to provide a double cantilever E-type reverse nested left-hand material with an adjustable cross wire structure.

The invention is provided with a dielectric substrate, a double cantilever E-shaped metal wire and a cross metal wire structure; the double cantilever E-shaped metal wire is reversely etched symmetrically on one side of the dielectric substrate, and the middle arm of the interlaced nested E-shaped structure disconnected, the cross wire structure is disposed on the back of the dielectric substrate.

The dielectric substrate can be a microwave dielectric material substrate, the dielectric constant of the dielectric substrate can be 2-10, preferably 4.4±5%; the thickness of the dielectric substrate can be 0.25-1.3mm, preferably 0.40mm±5% .

The cross metal wire can adopt an evenly distributed adjustable cross metal wire, and the evenly distributed adjustable cross metal wire can adopt at least two sets of periodic double cantilever E-type metal wire structure arrays, and the cross metal wire It has the same cycle and the same spacing as the double cantilever E-shaped metal wire.

The invention realizes the easy control of the length of each side of the double cantilever E-shaped structure of the left-hand material, the coupling degree of the two cantilever E-shaped metal wires, and the orthogonal overlapping position of the cross structure. By adjusting the geometric parameters of the unit, one or more can be realized. The left-hand band is controllable. Due to the adoption of the above structure, the left-handed characteristics of the array structure do not change when the direction of the incident wave and the polarization direction of the electric field are changed while keeping the polarization direction of the magnetic field unchanged, and the incident angle of the electromagnetic wave is widened. The new microwave left-handed material prepared in this way It is a new type of double-incident left-handed material, which can realize the incident from two directions and show the left-handed characteristics at the same time. It has the advantage of being able to show the same left-handed performance from multi-directional incidents in practical applications, and realizes the multi-dimensionalization and integration of left-handed materials. Multidirectional.

Description of drawings

FIG. 1 is a schematic diagram of a new double-incidence left-handed material with double-cantilever E-type reverse nesting with a uniformly distributed and adjustable cross wire structure in an embodiment of the present invention.

Fig. 2 is the structure of the adjustable cross wire unit on the back of the left-hand material in the embodiment of the present invention.

Figure 3 shows that the embodiment of the present invention etches a periodic double cantilever E-shaped structure on a high-performance dielectric material microwave substrate, and engraves at least 3 units along the propagation direction of the wave, and arranges them in at least 3 rows The substrate forms a periodic structure in two directions, and realizes the left-handed characteristic and the double-incidence left-handed characteristic as a whole.

Figure 4 shows the corresponding parameters (center distance is 3.00±0.01mm, side length a=2.00±0.01mm, width w=0.20±0.01mm, b=2.20±0.01mm, center side length, d=0.15±0.01mm, When p=0.05±0.01mm, w=0.25±0.01mm, L=3.00±0.01mm) samples are filled in the waveguide, the amplitude of waveguide port transmission coefficient S12 and port reflection coefficient S11.

Figure 5 shows the corresponding parameters (center distance is 3.00±0.01mm, side length a=2.00±0.01mm, width w=0.20±0.01mm, b=2.20±0.01mm, center side length, d=0.15±0.01mm, When p=0.05±0.01mm, w=0.25±0.01mm, L=3.00±0.01mm) samples are filled in the waveguide, the phase of waveguide port transmission coefficient S12 and port reflection coefficient S11 phase.

FIG. 6 is the real part of the equivalent dielectric constant for the samples in FIG. 4 .

FIG. 7 shows the equivalent magnetic permeability of the samples in FIG. 4 .

Fig. 8 is to change the incidence of the electromagnetic wave in the direction of the x-axis, let the electromagnetic wave enter in the direction of the y-axis, and keep the polarization direction of the magnetic field unchanged. When the above sample is filled in the waveguide, the magnitude of the waveguide port transmission coefficient S12 and the magnitude of the port reflection coefficient S11.

FIG. 9 shows changing the incidence of electromagnetic waves in the direction of the x-axis, making the incidence of electromagnetic waves in the direction of the y-axis, and keeping the polarization direction of the magnetic field unchanged. When the above sample is filled in the waveguide, the phase of the waveguide port transmission coefficient S12 and the phase of the port reflection coefficient S11.

detailed description

The present invention will be further described below in conjunction with embodiment and accompanying drawing.

Referring to Figures 1 to 3, the embodiment of the present invention is provided with at least 3 rows of high-performance dielectric material microwave substrates 1; one side 11 of the high-performance dielectric material microwave substrate 1 is etched with at least 3 double cantilever E-type metal wire units , the double cantilever E-type metal wire unit is composed of two E-type metal wires 12 that are reversely dislocated and symmetrically nested, and at least three cross metal wire units are etched on the other side 21 of the microwave substrate 1 made of high-performance dielectric material 22, the number of the cross metal wire unit 22 and the double cantilever E-type metal wire unit are the same, the transverse side 221 of the cross metal wire unit 22 is perpendicular to the longitudinal side 121 of the double cantilever E-type metal wire unit, and the cross metal wire unit The longitudinal side 222 of the line unit 22 is parallel to the longitudinal side 121 of the double cantilever E-type metal wire unit, and the center of the double-cantilever E-type metal wire unit is at the same level as the center of the cross metal wire unit. The distance between them is the same, and the distance between the cross metal wire units is the same.

The dielectric constant of the high-performance dielectric material microwave substrate 1 is 2-10, preferably 4.4±5%. The thickness can be 0.25~1.3mm, preferably 0.40mm±5%.

The length a of the outer side of the E-shaped metal wire 12 can be 2-3mm, the width w=0.05-0.25mm of each side of the metal, the length b=1-2.5mm of the inner side of the double cantilever E, and the distance between the center side and the side The distance between them is d=0.1-0.5mm, the distance between the corresponding sides of the two cantilevers E is p=0.1-0.5mm, and the thickness is 0.01-0.03mm. Its typical values are a=2.00±0.01mm, w=0.20±0.01mm, b=2.20±0.01mm, d=0.15±0.01mm, p=0.05±0.01mm, and the thickness of the metal wire is 0.018mm±5%.

The length of the cross wire 22 is L=2-6 mm, the width w=0.10-0.30 mm, and the thickness is 0.01-0.03 mm. Its typical value is L=3.00±0.01mm, w=0.25±0.02mm, and the thickness is 0.018mm±5%.

After optimizing the combination, different electromagnetic parameters of left-handed materials can be obtained, including equivalent permittivity and equivalent permeability. In the range of 3-12GHz, the equivalent permittivity and equivalent permeability at a certain frequency point can be negative at the same time by geometric parameter tuning control.

The invention adopts circuit board etching technology to etch at least three identical metal copper double cantilever E-type units on one side of a polytetrafluoroethylene substrate with a thickness of 0.40mm±5% to form a periodic array, and the periodically repeated metal Copper double cantilever E-type units must be distributed on an axis perpendicular to the longitudinal side of the double cantilever E-type metal copper wire, the center distance is 6.5±3.5mm, the thickness of metal copper is 0.018mm±5%, symmetrical metal copper double cantilever The outer length of the E-type unit is a=2.00±0.01mm, the width of the side is w=0.20±0.01mm, the length of the central side of the double-cantilever E-type unit is b=2.20±0.01mm, and the distance between the central side and the side is d= 0.15±0.01mm, the distance between the corresponding sides of the two double cantilevers E is p=0.05±0.01mm; the other side of the PTFE substrate corresponds to the etching length L=3.00±0.01mm from the center of the structure of the double cantilever E , a periodic array of cross metal wires with a width w=0.25±0.02mm, and the repeat period is the same as that of the double cantilever E structure. The fabricated periodic array structure in one direction is also arranged in at least three rows in the axial direction of the high-performance dielectric material microwave substrate to form a periodic array as shown in Figure 3, and the distance between adjacent substrates is 1.25mm. The periodic array structure made in this way can be made to be able to work in a specific The left-handed material is composed of double cantilever E structure and cross metal wire in the frequency band, and has different equivalent permittivity, equivalent magnetic permeability and equivalent refractive index.

Embodiment one:

Using typical PCB plate making technology, etch at least three identical metal copper double cantilever E-type units on one side of the PTFE substrate with a thickness of 0.40mm±5% copper clad foil thickness e=0.018mm±5%. The structure constitutes a periodic array, and the periodically repeated metal copper double cantilever E-shaped structure must be arranged on an axis parallel to the three horizontal sides of the E-shaped structure. Among them, the center distance is 3.00±0.01mm, the outer side length of the symmetrical double-cantilever E-shaped structure is a=2.00±0.01mm, the width of each side of the metal is w=0.20±0.01mm, and the length of the central side of the double-cantilever E-shaped structure is b=2.20 ±0.01mm, the distance between the center side and the side side d=0.15±0.01mm, the distance between the corresponding sides of the two double cantilever E-shaped structures p=0.05±0.01mm. On the other side, the center is etched to correspond to the center position of the double cantilever E-shaped structure and the straight sides are perpendicular to the three horizontal sides of the E-shaped structure. There is an array of uniformly distributed and adjustable cross metal wire structures with the same period, and the evenly distributed adjustable The width of the two mutually perpendicular lines of the cross wire structure is w=0.25±0.01mm, and the length of the lines is L=3.00±0.01mm. The thus-prepared periodic left-handed material with five unit structures in the incident direction of the microwave is placed side by side in the waveguide cavity to form a periodicity of three unit structures in the direction of the magnetic field H. The electromagnetic wave is incident from the x direction, and the port transmission coefficient and reflection coefficient of the waveguide loaded with the left-hand material are measured. The amplitude of the waveguide port transmission coefficient S12 and the port reflection coefficient S11 are shown in Figure 4. The phase of the waveguide port transmission coefficient S12 The phase with the port reflection coefficient S11 is shown in Figure 5, and the equivalent dielectric constant calculated from the measured coefficient is shown in Figure 6, and the equivalent magnetic permeability is shown in Figure 7. The results show that in the frequency domain around 10GHz, the equivalent permittivity and permeability are both negative, which indicates that the structure can be used as a left-handed material around 10GHz.

Embodiment two:

Using typical PCB plate making technology, etch at least three identical metal copper double cantilever E-type units on one side of the PTFE substrate with a thickness of 0.40mm±5% copper clad foil thickness e=0.018mm±5%. The structure constitutes a periodic array, and the periodically repeated metal-copper double cantilever E-shaped structure must be arranged on an axis parallel to the three horizontal sides of the E-shaped structure. Among them, the center distance is 3.00±0.01mm, the outer side length of the symmetrical double-cantilever E-shaped structure is a=2.00±0.01mm, the width of each side of the metal is w=0.20±0.01mm, and the length of the central side of the double-cantilever E is b=2.20±0.01 mm, the distance between the central side and the side side d=0.15±0.01mm, and the distance between the corresponding sides of the two double cantilever E-shaped structures p=0.05±0.01mm. On the other side, the center is etched corresponding to the center position of the double cantilever E-shaped structure, and the straight sides are perpendicular to the three horizontal sides of the E-shaped structure. An array of uniformly distributed and adjustable cross metal wire structures with the same period is etched. The width of the lines perpendicular to each other is w=0.25±0.01mm, and the length of the lines is L=3.00±0.01mm. The periodic left-handed material with 5 unit structures prepared in this way is placed side by side in the waveguide cavity to form a periodicity of 3 unit structures in the direction of the magnetic field H, but the electromagnetic wave is incident from the y direction, Keeping the polarization direction of the magnetic field unchanged, the port transmission coefficient and reflection coefficient of the waveguide installed in the left-hand material are measured. The magnitude of the waveguide port transmission coefficient S12 and the port reflection coefficient S11 are shown in Figure 8. The waveguide port transmission coefficient S12 The phase and the phase of the port reflection coefficient S11 are shown in FIG. 9 . As can be seen from Figures 8 and 9, when the present invention is incident with electromagnetic waves from two directions, there is no difference in the simulation calculation results, and the equivalent permittivity and magnetic permeability are both negative in the frequency domain around 10 GHz, indicating that there is a uniformly distributed adjustable The double cantilever E-type reverse nested left-handed material with a cross metal wire structure can realize the left-handed characteristics of incidence in two mutually perpendicular directions, and is a double-incidence left-handed material.

Claims (6)

1. with double cantilever E types reversely nested LHM of adjustable cross metal wire structure, it is characterised in that be provided with dielectric substrate, double cantilever E type metal wire and cross metal wire structure；Described pair of cantilever E type metal wire reverse symmetry is etched in the side of dielectric substrate, and staggered nested E word structure intermediate arm disconnects, and described cross metal wire structure is located at the opposite side of dielectric substrate；Described double cantilever E types with adjustable cross metal wire structure reversely nested LHM uses at least 2 group the most double cantilever E type metal wire structure array；Described cross metal wire and double cantilever E type metal wires are with cycle same spacing；

The horizontal edge of described cross metal wire unit is vertical with the longitudinal edge of double cantilever E type metal wire unit, the longitudinal edge of described cross metal wire unit is parallel with the longitudinal edge of double cantilever E type metal wire unit, and the center of double cantilever E type metal wire unit and the center of cross metal wire unit are at same level height.

2. as claimed in claim 1 with double cantilever E types reversely nested LHM of adjustable cross metal wire structure, it is characterised in that described dielectric substrate uses microwave dielectric material substrate.

3. as claimed in claim 1 with double cantilever E types reversely nested LHM of adjustable cross metal wire structure, it is characterised in that the dielectric constant of described dielectric substrate is 2～10.

4. as claimed in claim 3 with double cantilever E types reversely nested LHM of adjustable cross metal wire structure, it is characterised in that the dielectric constant of described dielectric substrate is 4.4 ± 5%.

5. as claimed in claim 1 with double cantilever E types reversely nested LHM of adjustable cross metal wire structure, it is characterised in that the thickness of described dielectric substrate is 0.25～1.3mm.

6. as claimed in claim 5 with double cantilever E types reversely nested LHM of adjustable cross metal wire structure, it is characterised in that the thickness of described dielectric substrate is 0.40mm ± 5%.