An electromagnetic wave isolator based on electrocyclotron dielectric material

Abstract

The present invention discloses an electromagnetic wave isolator based on an electrocyclotron dielectric material, which includes 10 stacked dielectric layers, the 10 stacked dielectric layers are divided into 5 groups, from left to right, 3 groups of A and B stacked dielectric layers, 2 groups of D and C stacked dielectric layers, the A dielectric layer and the C dielectric layer are respectively made of silicon dioxide material and silicon material, and the B dielectric layer and the D dielectric layer are both electrocyclotron materials. The present invention uses external incident electromagnetic waves to form surface waves in the Tamm state with unidirectional propagation properties on the interface of two multilayer structures composed of dielectric layers and electrocyclotron dielectric materials, thereby realizing unidirectional propagation of electromagnetic waves; and the special relationship between electrocyclotron materials and external magnetic fields is used to realize the non-reciprocity of electromagnetic waves, and the frequency and characteristics of unidirectional propagation can be changed by adjusting the thickness of the structural unit and the change of the incident angle.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic technology, in particular to an electromagnetic wave isolator based on an electrocyclotron medium material. Background Art

[0002] With the widespread application of electromagnetic waves in communications, optics and other scientific and technological fields, the propagation of electromagnetic waves has now developed into a rich interdisciplinary subject. The cyclotron medium is a kind of anisotropic medium. The Hermitian tensor exists in its constitutive parameters, making it non-reciprocal. Under the action of an external field, there are two typical cyclotron media: gyroelectric media and gyromagnetic media.

[0003] When an electromagnetic wave of a specific frequency is incident on a multilayer medium composed of two different cyclotron dielectrics, an optical Tamm state with non-reciprocal dispersion can be formed on the interface of the two multilayer structures. At the frequency of the Tamm state, a unidirectional electromagnetic wave tunneling effect can be achieved. The non-reciprocity of Tamm breaks the symmetry of time and space when electromagnetic waves propagate in the medium. Therefore, a multilayer structure composed of anisotropic electrocyclotron materials is constructed, and different interface optical Tamm states will be formed at incident waves of different angles and frequencies, thereby forming unidirectional propagation of electromagnetic waves and forming a isolator. The unidirectional transmission of electromagnetic waves in this structure is different from conventional isolators. Instead, the frequency of the electromagnetic waves that can pass through is changed by changes in the external magnetic field, the thickness of the dielectric layer and the angle of incidence. This theory of unidirectional transmission of electromagnetic waves provides a certain theoretical basis for the research of optical communication devices, optical sensors, etc.

[0004] Chinese patent application No. 2011102323367 discloses a cyclotron medium that does not require an external magnetic field and is composed of active artificial dielectric units. Four groups of orthogonal dipoles are arranged in a square on mutually parallel front and rear dielectric plates; the upper left and lower right groups of dipoles at the same position of the front and rear dielectric plates are connected to each other by rotating 90 degrees clockwise through an amplifier, and the amplifier direction uses the front dielectric plate dipole as input and the rear dielectric plate dipole as output, forming a unidirectional left-handed structure; and the upper right and lower left groups of dipoles at the same position of the front and rear dielectric plates are connected to each other by rotating 90 degrees clockwise through an amplifier, and the amplifier direction uses the rear dielectric plate dipole as input and the front dielectric plate dipole as output, forming a unidirectional right-handed structure; the above structure is extended outward periodically to form a cyclotron medium with non-reciprocal transmission characteristics as a whole. The above invention uses the unidirectional transmission characteristics of the amplifier to achieve non-reciprocal transmission of electromagnetic waves of arbitrary linear polarization, and can work by providing direct current. However, the above invention has a complex structure and still needs to rely on direct current to achieve non-reciprocal transmission of electromagnetic waves, which consumes a lot of energy and is not environmentally friendly. Summary of the invention

[0005] The purpose of the present invention is to solve the above technical problems. In the field of electromagnetic technology, the purpose is to make electromagnetic waves have unidirectional characteristics when transmitting by utilizing the anisotropy of the material itself to light and the non-reciprocal dispersion when electromagnetic waves are incident on the boundary of two different multilayer composite media. By changing the incident angle or the size of the external magnetic field, the structural frequency that can pass can be screened and the intensity of the unidirectional propagation of light can be enhanced, thereby reducing the structural cost.

[0006] The technical solution adopted by the present invention is as follows: an electromagnetic wave isolator based on electrocyclotron dielectric material, which includes 10 stacked dielectric layers, and the 10 stacked dielectric layers are divided into 5 groups, including 3 groups of A and B stacked dielectric layers and 2 groups of D and C stacked dielectric layers from left to right. The A dielectric layer and the C dielectric layer are respectively made of silicon dioxide material and silicon material, and the B dielectric layer and the D dielectric layer are both electrocyclotron materials.

[0007] The thickness of the A dielectric layer is 3-10 mm, the thickness of the B dielectric layer is 2-8 mm, the thickness of the C dielectric layer is 10-40 mm, and the thickness of the D dielectric layer is 20-25 mm.

[0008] The relative dielectric constants of the A dielectric layer and the C dielectric layer are 2.56 and 11.5 respectively.

[0009] The relative magnetic permeabilities of the A dielectric layer and the C dielectric layer are both 1.

[0010] The relative magnetic permeabilities of the B dielectric layer and the D dielectric layer are both 1.

[0011] The relative permittivity tensor of the B dielectric layer and the D dielectric layer is in the form of: .

[0012] The 10 stacked dielectric layers are placed in an air environment.

[0013] The B dielectric layer is in a static magnetic field that is perpendicular to the paper surface and extends outward.

[0014] The D dielectric layer is in a static magnetic field that is perpendicular to the paper surface and inward.

[0015] Specifically, the beneficial effects of the present invention are:

[0016] 1) Compared with the traditional structure, this structure is simple, easy to implement, and can achieve good results;

[0017] 2) Using external incident electromagnetic waves to form a Tamm state at the interface between the dielectric layer and the electrocyclotron dielectric material layer, thereby achieving unidirectional propagation of electromagnetic waves;

[0018] 3) The structure has low electromagnetic wave loss and a transmittance close to 1;

[0019] 4) The special relationship between the electrocyclotron material and the external magnetic field is used to realize the non-reciprocity of electromagnetic waves. The frequency of the unidirectional electromagnetic wave propagated by the structure can be adjusted by changing the size of the magnetic field. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention.

[0021] Figure 2 The figure shows the change of the transmission peak with the change of the thickness of the A dielectric layer when the external magnetic field is 0.02T, the thickness of the B dielectric layer is 5mm, the thickness of the C dielectric layer is 20mm, the thickness of the D dielectric layer is 22mm, and the incident angle is 30°. The thickness of the A dielectric layer is 6mm, 6.5mm, 7mm and 7.5mm respectively. The black solid line in the figure shows the change of the transmission coefficient of the forward propagating electromagnetic wave with frequency, and the black dotted line shows the change of the transmission coefficient of the reverse propagating electromagnetic wave with frequency.

[0022] Figure 3 When the external magnetic field is 0.02T, the thickness of dielectric layer A is 6.5mm, the thickness of dielectric layer B is 5mm, the thickness of dielectric layer C is 20mm, the thickness of dielectric layer D is 22mm, and the incident angle is 30°, the incident wave frequencies are f=0.4275GHz and f=0.4285GHz respectively. The electric field E x The spatial distribution of components.

[0023] Figure 4 The relationship between the transmission peak and the thickness of the C dielectric layer when the external magnetic field is 0.02T, the thickness of the A dielectric layer is 6.5mm, the thickness of the B dielectric layer is 5mm, the thickness of the D dielectric layer is 22mm, and the incident angle is 30°. The thickness of the C dielectric layer is 20mm, 25mm, 30mm and 35mm respectively. The black solid line in the figure represents the change of the transmission coefficient of the forward propagating electromagnetic wave with the frequency, and the black dotted line represents the change of the transmission coefficient of the reverse propagating electromagnetic wave with the frequency.

[0024] Figure 5 The relationship between the transmission peak and the change of the external magnetic field when the thickness of the A dielectric layer is 6.5mm, the thickness of the B dielectric layer is 5mm, the thickness of the C dielectric layer is 20mm, the thickness of the D dielectric layer is 22mm, and the incident angle is 30°. The magnitude of the magnetic field is 0.016T, 0018T, 002T and 0.022T respectively. The black solid line in the figure represents the change of the transmission coefficient of the forward propagating electromagnetic wave with frequency, and the black dotted line represents the change of the transmission coefficient of the reverse propagating electromagnetic wave with frequency.

[0025] Figure 6The relationship between the transmission peak and the incident angle of the electromagnetic wave when the external magnetic field is 0.02T, the thickness of the dielectric layer A is 6.5mm, the thickness of the dielectric layer B is 5mm, the thickness of the dielectric layer C is 20mm, the thickness of the dielectric layer D is 22mm, and the incident angle is 30°. The magnitude of the incident angle is respectively In the figure, the solid black line represents the variation of the transmission coefficient of the forward propagating electromagnetic wave with frequency, and the dotted black line represents the variation of the transmission coefficient of the reverse propagating electromagnetic wave with frequency. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0027] like Figure 1-6 As shown, the present invention includes 10 stacked dielectric layers, which are placed in an air environment and can achieve unidirectional propagation of different wavelengths and frequencies. The 10 stacked dielectric layers are divided into 5 groups, including 3 groups of A and B stacked dielectric layers and 2 groups of D and C stacked dielectric layers from left to right. The A dielectric layer and the C dielectric layer are silicon dioxide material and silicon material respectively, the B dielectric layer and the D dielectric layer are both electrocyclotron materials, the thickness of the A dielectric layer is 3-10 mm, the thickness of the B dielectric layer is 2-8 mm, the thickness of the C dielectric layer is 10-40 mm, and the thickness of the D dielectric layer is 20-25 mm.

[0028] The relative dielectric constants of the A dielectric layer and the C dielectric layer are 2.56 and 11.5 respectively, and the relative magnetic permeabilities are both 1; the relative magnetic permeabilities of the B dielectric layer and the D dielectric layer are both 1.

[0029] The B dielectric layer is in a static magnetic field that is perpendicular to the paper surface and extends outward.

[0030] The D dielectric layer is in a static magnetic field that is perpendicular to the paper surface and inward, and has an opposite direction to the static magnetic field of the B dielectric layer, but has the same magnitude.

[0031] The relative permittivity tensor of the B dielectric layer and the D dielectric layer is in the form of:

[0032] (1)

[0033] in ,here is the cyclotron frequency, is the plasma frequency, is the angular frequency of the applied magnetic field. By combining Maxwell's equations, transmission matrix theory and electromagnetic boundary conditions, the transmission characteristics of electromagnetic waves incident from air to a multilayer structure composed of an electrocyclotron medium are derived, and then the frequency of electromagnetic waves that can propagate unidirectionally in this structure is derived. In this structure, the numerical analysis method uses the transmission matrix method, and the Fortran language is used to compile and simulate for verification.

[0034] For the incident electric field, the electromagnetic wave has the following expression:

[0035] (2)

[0036] (3)

[0037] (4)

[0038] (5)

[0039] in (Equations (2) and (3)) respectively represent the forms of the electric field and magnetic field incident on the medium from the air on the left. Respectively Wave vectors in three directions. Equations (4) and (5) are derived based on Maxwell equations and electromagnetic field boundary conditions. The relationship between the electric field component in the direction and the y component of the magnetic field.

[0040] Substituting (4) and (5) into Maxwell's equations, we can obtain the equations satisfied by the magnetic field components and obtain the propagation vector k in the z direction: z The form of magnetic field components in the dielectric layer is:

[0041] (6)

[0042]

[0043] (7)

[0044] According to (4) and (5), the electric field E x The magnetic field component H in the dielectric layer y Indicates:

[0045]

[0046] (8)

[0047] in , . Equation (6) is derived from Maxwell's equations The wave equation satisfied by the magnetic field components in the direction. According to the relationship between the electromagnetic field components, T j The relationship between the transverse components of the electric and magnetic fields in the dielectric layer in the form of a matrix:

[0048] (9)

[0049] (10)

[0050] (10) respectively represents The inverse form of the relationship matrix between the electric field and magnetic field at the interface of the layer. According to the continuity condition of the electromagnetic field components at the boundary, the adjacent Layer and The relationship matrix of the transverse components of the electromagnetic field in the layer:

[0051] (11)

[0052] Similarly, the T matrix relationship between the air layer (Air) and the first dielectric layer (Dielectric) and the last layer (Dielectric) and the air layer (Air) can be obtained: AD and T DA :

[0053] (12)

[0054] (13)

[0055] At any thickness l D The phase change relationship of the dielectric layer from front to back is:

[0056] (14)

[0057] From this, we can obtain the composite propagation matrix from air to medium, in the medium and from the medium to air:

[0058] (15)

[0059] It can be concluded that the incident wave, reflected wave and transmitted wave satisfy the following relationship:

[0060] (16)

[0061] From the propagation relationship of equation (16), the transmission coefficient t and reflection coefficient r of electromagnetic waves passing through the multilayer structure can be obtained:

[0062] (17)

[0063] (18)

[0064] The changing patterns of transmission coefficient and reflection coefficient can intuitively reflect the propagation patterns of electromagnetic waves in multi-layer media.

[0065] Embodiment 1:

[0066] like Figure 2 As shown, the peak shift of the incident electromagnetic wave is discussed for the thickness change of the dielectric layer of material A. In this structure, the characteristics of the dielectric layer B are: the thickness is selected as 5 mm, and the relative dielectric constant is determined by formula (1), where , the relative magnetic permeability is 1. Characteristics of the C dielectric layer: the thickness is selected as 20mm, the relative magnetic permeability is 1, and the dielectric constant is 11.5. Characteristics of the D dielectric layer: the thickness is selected as 22mm, the relative magnetic permeability is 1, and the incident angle is 30°. At the same time, the left side of the structure (i.e., the B dielectric layer) is in a static magnetic field perpendicular to the paper surface and outward, with a magnetic field size of 0.02T, and the right side of the structure (i.e., the C dielectric layer) is in a static magnetic field perpendicular to the paper surface and inward, with the same magnetic field size as the left side.

[0067] At this time, the dielectric layer A is a silicon dioxide dielectric layer with a dielectric constant of 2.56 and a relative magnetic permeability of 1. The thickness of the dielectric layer A is changed to 6 mm, 6.5 mm, 7 mm and 7.5 mm, respectively, corresponding to Figure 2 From Figures (a), (b), (c) and (d) in the figure, it can be found that the frequencies of forward propagation (peak of the black solid line) and reverse propagation (peak of the black dashed line) shift to the left as the thickness of the A medium layer increases, and the peak distance is stable.

[0068] Embodiment 2:

[0069] like Figure 3 As shown, in Example 1 Figure 2 The conditions of (b) are the same, that is, the thicknesses of the A, B, C and D dielectric layers are 6.5 mm, 5 mm, 20 mm and 22 mm respectively; the B and D dielectric layers are both electrocyclotron materials with a relative magnetic permeability of 1. The relative dielectric constant is determined by formula (1), where , a static magnetic field of B=0.02T is applied outward and inward respectively. A and C are non-magnetic dielectric layers of silicon dioxide and silicon respectively, with relative magnetic permeability of 1 and relative dielectric constants of 2.56 and 11.5 respectively.

[0070] Depend on Figure 3 The two reciprocal transmission peak frequencies in (b) are the reverse transmission peak f = 0.4275 GHz and the forward transmission peak f = 0.4285 GHz. Figure 3 (a) is the E corresponding to the reverse transmission peak at f=0.4275GHz xThe distribution diagram of the components in the YZ plane shows that the electric field can be completely transmitted through the multilayer structure, while when incident in the forward direction, a standing wave is formed on the incident surface and cannot pass through the multilayer structure, such as Figure 3 As shown in (b). When the forward transmission peak f = 0.4285GHz forward incident wave passes through the multilayer structure, the electromagnetic wave can pass through completely, as shown in Figure 3 As shown in (c), when this frequency passes through the multilayer structure in the reverse direction, a standing wave is formed in the incident area and cannot propagate (as shown in Figure 3 (shown in (d)).

[0071] Embodiment 3:

[0072] like Figure 4 As shown in the figure, the peak shift of the incident electromagnetic wave is discussed for the thickness change of the dielectric layer of material C. In this structure, the characteristics of dielectric layer A are: the thickness is selected as 6.5 mm, the dielectric constant is 2.56, and the magnetic permeability is 1. The characteristics of dielectric layer B are: the thickness is selected as 5 mm, and the relative dielectric constant is determined by formula (1), where , the relative magnetic permeability is 1. Characteristics of the D dielectric layer: the thickness is selected as 22mm, the relative magnetic permeability is 1, and the incident angle is 30°. At the same time, the left side of the structure (i.e., the B dielectric layer) is in a static magnetic field perpendicular to the paper surface and outward, with a magnetic field size of 0.02T, and the right side of the structure (i.e., the C dielectric layer) is in a static magnetic field perpendicular to the paper surface and inward, with the same magnetic field size as the left side.

[0073] At this time, the C dielectric layer is a silicon material dielectric layer with a relative dielectric constant of 11.5 and a relative magnetic permeability of 1. The thickness of the C dielectric layer is observed and the values ​​are 20mm, 25mm, 30mm and 35mm, respectively, corresponding to Figure 2 From the (a), (b), (c) and (d) diagrams, we can see that the frequencies of forward propagation (peak of the black solid line) and reverse propagation (peak of the black dashed line) shift to the left as the thickness of the C medium layer increases, and the peak distance is stable.

[0074] Embodiment 4:

[0075] like Figure 5 As shown, the magnitude of the external magnetic field is changed to explore the peak shift of the incident electromagnetic wave. In this structure, the characteristics of the A dielectric layer: the thickness is selected as 6.5mm, the dielectric constant is 2.56, and the relative magnetic permeability is 1. The characteristics of the B dielectric layer: the thickness is selected as 5mm, , the relative magnetic permeability is 1. Characteristics of the C dielectric layer: the thickness is selected as 20 mm, the relative dielectric constant is 11.5, and the magnetic permeability is 1. Characteristics of the D dielectric layer: the thickness is selected as 22 mm, the relative magnetic permeability is 1, and the incident angle is 30°.

[0076] At this time, the change of the applied magnetic field is observed, and B=0.016T, B=0.018T, B=0.02T and B=0.022T correspond to Figure 4 Figures (a), (b), (c) and (d) show that as the magnetic field changes, the forward and reverse propagation peaks shift significantly to the right (where the black solid line and dashed line are), and the peak distance becomes larger and larger.

[0077] Embodiment 5:

[0078] like Figure 6 As shown, the incident angle of the electromagnetic wave is changed to explore the peak shift of the incident electromagnetic wave. In this structure, the characteristics of the A dielectric layer: the thickness is selected as 6.5mm, the relative dielectric constant is 2.56, and the relative magnetic permeability is 1. The characteristics of the B dielectric layer: the thickness is selected as 5mm, and the relative dielectric constant is determined by formula (1), where , the magnetic permeability is 1. Characteristics of the C dielectric layer: the thickness is selected as 20mm, the relative dielectric constant is 11.5, and the relative magnetic permeability is 1. Characteristics of the D dielectric layer: the thickness is selected as 22mm, and the relative magnetic permeability is 1. At the same time, the incident angle is 30°, and the magnitude of the external magnetic field is B=0.02T.

[0079] At this time, observe the change of the incident angle and take Corresponding to Figure 4 Figures (a), (b), (c) and (d) show that as the magnetic field changes, the peaks of the forward and reverse propagation shift significantly to the right (where the black solid line and dashed line are), and the peak distance becomes larger and larger.

[0080] By comparing the above five implementation cases, we can conclude that:

[0081] When the thickness of the A and C dielectric layers increases, the forward and reverse propagation transmission peaks shift to the left (i.e., the positions of the black solid and dotted lines), and the peak distances remain stable.

[0082] When the incident angle θ When increases, the forward and reverse propagation transmission peaks will also shift to the right (that is, the position of the black solid line and dotted line), and the peak distance will also increase significantly.

[0083] When the magnetic field changes, the forward and reverse propagation transmission peaks are greatly affected. First, the transmission peak shifts significantly to the right (that is, the position of the black solid line and the dotted line), and the peak distance becomes larger and larger. Therefore, the change in external magnetic field conditions is one of the main determining factors for regulating structural reciprocity.

[0084] Other unexplained parts of the present invention are the same as those of the prior art.

Claims

1. An electromagnetic wave isolator based on electrocyclotron dielectric material, characterized in that It includes 10 stacked dielectric layers, which are divided into 5 groups, including 3 groups of A and B stacked dielectric layers and 2 groups of D and C stacked dielectric layers from left to right, wherein the A dielectric layer and the C dielectric layer are made of silicon dioxide material and silicon material respectively, and the B dielectric layer and the D dielectric layer are both electrocyclotron materials; The thickness of the A dielectric layer is 3-10 mm, the thickness of the B dielectric layer is 2-8 mm, the thickness of the C dielectric layer is 10-40 mm, and the thickness of the D dielectric layer is 20-25 mm; The dielectric constants of the A dielectric layer and the C dielectric layer are 2.56 and 11.5 respectively; The relative magnetic permeabilities of the A dielectric layer and the C dielectric layer are both 1; The relative magnetic permeabilities of the B dielectric layer and the D dielectric layer are both 1; The relative permittivity tensor of the B dielectric layer and the D dielectric layer is in the form of: ,in ,here is the cyclotron frequency, is the plasma frequency, is the angular frequency of the applied magnetic field; The 10 stacked dielectric layers are placed in an air environment; The B dielectric layer is in a static magnetic field that is perpendicular to the paper and extends outward; The D dielectric layer is in a static magnetic field that is perpendicular to the paper surface and inward.

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