A 220 GHz semi-compressed Luneburg lens antenna for beam scanning

Abstract

The present invention discloses a 220GHz semi-compressed Luneburg lens antenna for realizing beam scanning, comprising a semi-compressed Luneburg lens and a feed source; wherein the semi-compressed Luneburg lens comprises a first part in a semi-ellipsoidal shape and a second part in a semi-spherical shape; the first part is located on the top of the second part; the bottom surface of the first part is directly corresponding to and connected to the top surface of the second part; the length of the major axis of the first part is equal to the diameter of the second part; the semi-ellipsoidal shape of the first part is obtained by vertically compressing the upper half of the original spherical Luneburg lens antenna downward toward the sphere center direction of the Luneburg lens antenna; the feed source is located above the first part and is used to radiate electromagnetic waves directed to the semi-compressed Luneburg lens. The present invention realizes a large-angle beam scanning function by placing the feed source on a plane opposite to the semi-compressed Luneburg lens and then changing the position of the feed source on the plane, and has the characteristics of high gain and large-angle beam scanning.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a 220GHz semi-compressed Luneburg lens antenna for realizing beam scanning. Background Art

[0002] At present, for military radar systems, imaging systems and communication systems, in order to improve the signal coverage, certain requirements are put forward for the beam scanning function.

[0003] The Luneburg lens was proposed in 1944. Any point on the lens can be used as the focus of the lens. Therefore, by placing the feed on the surface of the Luneburg lens, a large-angle beam scanning function can be achieved. However, since the Luneburg lens is spherical and the focus is a spherical surface (that is, all focal points are located on the spherical surface), its application in many fields is limited.

[0004] Therefore, there is an urgent need to develop a technology that can solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a 220 GHz semi-compressed Luneburg lens antenna for beam scanning in view of the technical defects in the prior art.

[0006] To this end, the present invention provides a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning, which includes a semi-compressive Luneburg lens and a feed source;

[0007] Wherein, the semi-compressive Luneburg lens comprises a first part in a semi-ellipsoidal shape and a second part in a semi-spherical shape;

[0008] The first section is placed on top of the second section;

[0009] The bottom surface of the first part is directly connected to the top surface of the second part;

[0010] The length of the major axis of the first portion is equal to the diameter of the second portion;

[0011] The semi-ellipsoidal shape of the first part is obtained by compressing the upper half of the original spherical Luneburg lens antenna vertically downward toward the center of the Luneburg lens antenna;

[0012] A feed source, located above the first part, is used for radiating electromagnetic waves directed toward the semi-compressive Luneburg lens.

[0013] It can be seen from the technical solution provided by the present invention that, compared with the prior art, the present invention provides a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning. The antenna has a scientific design and realizes a large-angle beam scanning function by placing the feed on a plane opposite to the semi-compressive Luneburg lens and then changing the position of the feed on the plane. The antenna has the characteristics of high gain and large-angle beam scanning and has great practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1a Schematic diagram of the original (i.e., existing) spherical Luneburg lens before and after compression, wherein the dotted line is the shape of the upper half of the spherical Luneburg lens before compression, and the solid line is the semi-ellipsoidal shape of the upper half of the Luneburg lens after compression and the shape of the lower half (the second part of the hemispherical shape) that is not compressed;

[0015] Figure 1b The present invention provides a schematic diagram of the shape of a semi-compressive Luneburg lens used in a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning; Figure 1b The dotted line in is the separation position between the first part and the second part, and also the contact position;

[0016] Figure 2 The present invention provides a layered structure of a semi-compressive Luneburg lens and a schematic diagram of the dielectric constant distribution of each layer used in a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning;

[0017] Figure 3a The present invention provides a stereoscopic perspective schematic diagram of a horn when a 220GHz semi-compressed Luneburg lens antenna for beam scanning is used as a feed source;

[0018] Figure 3b The present invention provides a front view of a horn when a 220GHz semi-compressed Luneburg lens antenna for beam scanning is used as a feed source;

[0019] Figure 3c The present invention provides a bottom view of a horn when a 220GHz semi-compressed Luneburg lens antenna for beam scanning is used as a feed source;

[0020] Figure 3d The present invention provides a left view of a horn when a 220GHz semi-compressed Luneburg lens antenna for beam scanning is used as a feed source;

[0021] Figure 4 The present invention provides a schematic diagram of the position relationship between the horn and the semi-compressive Luneburg lens when a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning adopts a horn as a feed source, that is, a schematic diagram of a feeding method;

[0022] Figure 5 The invention provides a gain diagram of simulation results of a semi-compressive Luneburg lens and a horn when a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning adopts a horn as a feed source. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0027] See also Figures 1a to 5 , the present invention provides a 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning, comprising a semi-compressive Luneburg lens 100 and a feed source 200;

[0028] The semi-compressive Luneburg lens 100 includes a first portion 101 in a semi-ellipsoidal shape and a second portion 102 in a hemispherical shape;

[0029] The first part 101 is located on top of the second part 102;

[0030] The bottom surface of the first part 101 is in correspondence with the top surface of the second part 102;

[0031] The length of the major axis of the first portion 101 is equal to the diameter of the second portion 102;

[0032] The semi-ellipsoidal shape of the first part 101 is obtained by compressing the upper half of the original (i.e., existing) spherical Luneburg lens antenna vertically downward toward the center of the Luneburg lens antenna;

[0033] The feed source 200 is located above the first part 101 and is used to radiate electromagnetic waves directed toward the semi-compressive Luneburg lens.

[0034] In the present invention, in a specific implementation, the semi-ellipsoidal shape of the first part 101 is obtained by compressing the upper part (i.e., half) of the original spherical Luneburg lens antenna vertically downward toward the center of the sphere, and the compression direction is perpendicular to the horizontal plane.

[0035] In the present invention, it should be noted that, since the original spherical Luneburg lens has a rotationally symmetric structure, it is only necessary to use optical transformation to calculate the dielectric constant distribution of one of its faces, and then by rotation, the dielectric constant distribution of the entire Luneburg lens can be obtained. With the center of the original spherical Luneburg lens as the origin O, a three-dimensional coordinate system XYZ is established, wherein the Z axis is vertically upward, the Y axis is horizontally to the right, and the X axis is horizontally forward (i.e., the Y axis is the horizontal axis, the X axis is the longitudinal axis, and the z axis is the vertical axis). The plane shown in the present invention is the YOZ plane in the coordinate system, and the YOZ plane is a section of the semi-compressive Luneburg lens containing the Y axis and the Z axis in the coordinate system (i.e., the section where the lens is cut along the Y axis). In the present invention, by calculating the dielectric constant distribution of the semi-compressive Luneburg lens in the YOZ plane and rotating the plane around the Z axis, the dielectric constant distribution of the semi-compressive Luneburg lens in three-dimensional space can be obtained.

[0036] The role of the X-axis is not discussed in the following text because the Luneburg lens is rotationally symmetric. Taking the two-dimensional plane YOZ, the three-dimensional situation can be obtained by rotation. In other words, the YOZ plane and the YOX plane are equivalent. Here, the YOZ plane is used to illustrate the problem. The YOZ plane is a section containing the Z axis and the Y axis.

[0037] Figure 1aShown is a schematic diagram of the original spherical Luneburg lens before and after compression, where the dotted line is the shape of the upper half of the spherical Luneburg lens before compression, the solid line is the semi-ellipsoidal shape of the upper half of the Luneburg lens after compression, and the shape of the lower half (the second part of the hemispherical shape) that has not been compressed.

[0038] See also Figure 1a , the diameter of the original spherical Luneburg lens shown by the dotted line is D. At this time, the relationship between the dielectric constant ε and the diameter D at any point on the spherical Luneburg lens is as shown in the following formula (1):

[0039]

[0040] Where D is the diameter of the original spherical Luneburg lens;

[0041] y and z are the position coordinates of any point on the original spherical Luneburg lens on the YOZ plane (i.e., the plane where the lens is cut along the Y axis, which is a cross-section).

[0042] The YOZ plane is a cross section of a semi-compressive Luneburg lens that contains the Y-axis and the Z-axis in the three-dimensional coordinate system XYZ;

[0043] The three-dimensional coordinate system XYZ is established with the center of the original spherical Luneburg lens as the origin O, wherein the Z axis is vertically upward, the Y axis is horizontally to the right, and the X axis is horizontally forward.

[0044] In a specific implementation, the upper half of the original spherical Luneburg lens antenna is compressed vertically downward toward the center of the sphere to obtain a first part 101 in a semi-ellipsoidal shape; the mathematical expression of the dielectric constant ε at any point on the first part 101 is shown in the following formula (2):

[0045]

[0046] Where D is the diameter of the original spherical Luneburg lens;

[0047] y and z are the position coordinates of any point on the first part 101 on the YOZ plane (i.e., the plane that cuts the lens along the Y axis, which is a cross-section);

[0048] The YOZ plane is a cross section of a semi-compressive Luneburg lens that contains the Y-axis and the Z-axis in the three-dimensional coordinate system XYZ;

[0049] The three-dimensional coordinate system XYZ is a three-dimensional coordinate system established with the center of the original spherical Luneburg lens as the origin O, in which the Z axis is vertically upward, the Y axis is horizontally to the right, and the X axis is horizontally forward;

[0050] b is the semi-minor axis value (i.e., half of the minor axis length) of the first part 101 of the semi-ellipsoidal shape. The value of b is less than D / 2, and the smaller the value of b is, the smaller the volume of the semi-compressed Luneburg lens is. At the same time, the required maximum value of the dielectric constant will increase, so a moderate value is needed. The value of b is more appropriately between 0.1-0.4.

[0051] It should be noted that the lens used in the present invention is a semi-compressed Luneburg lens, so only the upper half of the original Luneburg lens is optically transformed.

[0052] Figure 1b The diagram is a shape diagram of the semi-compressive Luneburg lens used in the present invention in the YOZ plane (i.e., the plane where the lens is cut along the Y axis, which is a cross-section); the YOZ plane is rotated 360° with the Z axis as the rotation axis to obtain the final semi-compressive Luneburg lens 100.

[0053] In the present invention, in a specific implementation, for the semi-compressed Luneburg lens 100 of the present invention, the dielectric constant distribution of any point on the upper half (i.e., the first part 101) must satisfy formula (2); the dielectric constant ε of any point on the lower half (i.e., the second part 102) satisfies the distribution relationship of the dielectric constant ε of any point on the original spherical Luneburg lens, that is, satisfies the following formula (3):

[0054]

[0055] In formula (3), D is the diameter of the original spherical Luneburg lens;

[0056] y and z are the position coordinates of any point on the second part 102 on the YOZ plane (i.e., the plane where the lens is cut along the Y axis, which is a cross-section).

[0057] The YOZ plane is a cross section of a semi-compressive Luneburg lens that contains the Y-axis and the Z-axis in the three-dimensional coordinate system XYZ;

[0058] The three-dimensional coordinate system XYZ is established with the center of the original spherical Luneburg lens as the origin O, wherein the Z axis is vertically upward, the Y axis is horizontally to the right, and the X axis is horizontally forward.

[0059] It should be noted that, for the present invention, the advantages of the Luneburg lens in high gain and large-angle scanning are utilized, and the spherical Luneburg lens is semi-compressed (that is, half of the sphere of the spherical Luneburg lens is compressed into a semi-ellipsoidal shape) through the method of transformation optics, and the dielectric constant of the Luneburg lens after transformation is obtained. After the dielectric constant is approximated and layered, a semi-compressed Luneburg lens is designed to meet the needs for large-angle scanning in various fields.

[0060] In the present invention, in a specific implementation, the feed source 200 is specifically a speaker feed source.

[0061] In the present invention, in a specific implementation, when the feed source 200 is a horn feed source, the central axis of the horn feed source is perpendicular to the top surface of the second portion 102 of the semi-compressive Luneburg lens 100;

[0062] The top surface of the second portion 102 is parallel to the horizontal plane.

[0063] In order to more clearly understand the technical solution of the present invention, the technical solution of the present invention is described below in conjunction with specific embodiments.

[0064] In the present invention, since it is impossible to obtain a continuous dielectric constant distribution for the semi-compressive Luneburg lens 100, it is necessary to perform a layering process. The layering method of this patent is an equal thickness layering method.

[0065] Since it is not possible to obtain a continuous dielectric constant in practice, it is treated in layers, e.g. Figure 2 As shown, the upper half (i.e., the first part 101) semi-ellipsoid and the lower half (i.e., the second part 102) hemisphere of the semi-compressive Luneburg lens 100 are both divided into 5 layers;

[0066] For the upper half (i.e., the first part 101) of the semi-ellipsoidal shape of the semi-compressed Luneburg lens 100, the semi-major axis of the innermost semi-ellipsoid is 1 mm, and the semi-minor axis is 0.5 mm. With each outward layer, the semi-major axis and the semi-minor axis of the semi-ellipsoid increase by 1 mm and 0.5 mm respectively. The dielectric constants are 3.98, 3.82, 3.5, 3.02 and 2.38 from the inner layer to the outer layer respectively.

[0067] For the hemispherical lower part (i.e., the second part 102) of the semi-compressive Luneburg lens 100, the radius of the innermost hemispherical layer is 1 mm, and the radius of the hemisphere increases by 1 mm with each outward layer. The dielectric constants of each layer from the inside to the outside are 1.99, 1.91, 1.75, 1.51 and 1.19 respectively.

[0068] See also Figures 3a to 3d As shown, the feed source of the present invention is a horn, and the antenna is fed by the horn. The size of the horn is as follows: Figures 3a to 3d The distance between the horn mouth and the upper surface of the semi-ellipsoid (i.e., the first part 101) is 0.9 mm. The beam scanning function is obtained by moving the horn along the Y axis (i.e., horizontal lateral movement). The feeding position of the horn is as follows: Figure 4 As shown in the figure, since the beam scanning is symmetrical about the Z axis, only the gain curve when the center of the horn is located at Y greater than 0 is given. The center of the horn is placed at Y = 0, 1, 2, 3 and 4 respectively. The gain of the horn and the lens is shown in Figure 5As shown, the original gain of the speaker is 12.5dBi. After adding the semi-compression Luneburg lens, the maximum gain of the overall structure formed by the speaker with the lens increases to 22.7dBi. By changing the Y coordinate value of the center of the speaker mouth, the maximum scanning angle of the overall structure formed by the speaker with the lens can reach 60°, and its gain is 19.8dBi.

[0069] In terms of specific implementation, Figures 3a to 3d , the dimensions of the relevant parts of the horn feed are shown in the figure, and the unit is mm. For example, the vertical height of the horn feed as a whole is 5.44 mm, and the vertical height of the horn mouth at its lower end is 2.72 mm.

[0070] In a specific implementation, the distance between the horn mouth of the horn feed and the upper surface of the semi-ellipsoid (i.e., the first part 101) is 0.9 mm. This is the vertical distance between the horn feed and the semi-compressive Luneburg lens of the present invention, and the distance between the horn mouth of the horn feed and the semi-compressive Luneburg lens on the Z axis. This size is obtained based on the maximum gain and is obtained through simulation.

[0071] In specific implementation, the horn feed source is installed above the semi-ellipsoid (i.e., the first part 101), and the vertical distance between it and the semi-ellipsoid (i.e., the coordinate of the Z axis) is fixed. By changing its horizontal position (i.e., the coordinate of the Y axis), the beam scanning function can be realized.

[0072] exist Figure 5 middle, Figure 5 The horn curve in represents the gain curve of the horn, and Y=0-4 is the overall gain of the horn and the semi-compressive Luneburg lens, wherein 0-4 refers to the horizontal distance between the center of the horn mouth and the center of the semi-compressive Luneburg lens (in mm, i.e., the distance in the Y-axis direction). By comparing these situations, it is explained that the Luneburg lens of the present invention has high gain and can realize the function of beam scanning.

[0073] Compared with the prior art, the 220 GHz semi-compressed Luneburg lens antenna for beam scanning provided by the present invention has the following beneficial effects:

[0074] The present invention optimizes the plane focal length and antenna size based on optical transformation, and after selecting a certain size and performing reasonable stratification, the lens gain can reach 22.7dBi and the beam scanning angle can reach ±60° in the frequency band of 220GHz.

[0075] It should be noted that the plane focal length refers to the distance between the plane where the horn mouth is located and the semi-compression Luneburg lens, that is, the distance on the Z axis (that is, the distance between the horn mouth of the horn feed source and the upper surface of the first part 101 of the semi-ellipsoid, for example, 0.9 mm), and the plane focal length means that the horn moves only along the Y axis. By changing the semi-minor axis value b of the first part 101 of the semi-ellipsoid shape, the distance from the plane where the horn mouth is located to the semi-compression lens can be optimized.

[0076] In the present invention, the optimization of the antenna size specifically refers to changing the value of b, where b is the semi-minor axis value (i.e., half of the minor axis length) of the first portion 101 of the semi-ellipsoidal shape. The value of b is less than D / 2, and the smaller the value of b is, the smaller the volume of the semi-compressed Luneburg lens is. At the same time, the maximum value of the dielectric constant required will increase, so a moderate value is required. The value of b is more appropriately between 0.1 and 0.4.

[0077] To sum up, compared with the prior art, the 220GHz semi-compressive Luneburg lens antenna for realizing beam scanning provided by the present invention has a scientific design. It realizes a large-angle beam scanning function by placing the feed source on a plane opposite to the semi-compressive Luneburg lens and then changing the position of the feed source on the plane. It has the characteristics of high gain and large-angle beam scanning and has great practical significance.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A 220 GHz semi-compressed Luneburg lens antenna for beam scanning, characterized in that: It includes a semi-compressive Luneburg lens (100) and a feed source (200); The semi-compressive Luneburg lens (100) comprises a first part (101) in a semi-ellipsoidal shape and a second part (102) in a hemispherical shape; The first portion (101) is located on top of the second portion (102); The bottom surface of the first part (101) is in direct correspondence with the top surface of the second part (102); The length of the major axis of the first portion (101) is equal to the diameter of the second portion (102); The semi-ellipsoidal shape of the first part (101) is obtained by compressing the upper half of the original spherical Luneburg lens antenna vertically downward toward the center of the Luneburg lens antenna; A feed source (200), located above the first part (101), used for radiating electromagnetic waves directed toward the semi-compressive Luneburg lens; The semi-ellipsoidal shape of the first part (101) is obtained by compressing the upper half of the original spherical Luneburg lens antenna vertically downward toward the center of the sphere, and the compression direction is perpendicular to the horizontal plane; The dielectric constant of any point on the first part (101) The mathematical expression of is shown in the following formula (2): ，（2）； Where D is the diameter of the original spherical Luneburg lens; y and z are the position coordinates of any point on the first part (101) on the YOZ plane; The YOZ plane is a cross section of a semi-compressive Luneburg lens that contains the Y-axis and the Z-axis in the three-dimensional coordinate system XYZ; The three-dimensional coordinate system XYZ is a three-dimensional coordinate system established with the center of the original spherical Luneburg lens as the origin O, in which the Z axis is vertically upward, the Y axis is horizontally to the right, and the X axis is horizontally forward; b is the semi-minor axis value of the first part (101) of the semi-ellipsoidal shape; The dielectric constant of any point on the second part (102) , satisfying the following formula (1): , Formula (3); Where D is the diameter of the original spherical Luneburg lens; y and z are the position coordinates of any point on the second part (102) on the YOZ plane; The YOZ plane is a cross section of a semi-compressive Luneburg lens that contains the Y-axis and the Z-axis in the three-dimensional coordinate system XYZ; The three-dimensional coordinate system XYZ is a three-dimensional coordinate system established with the center of the original spherical Luneburg lens as the origin O, in which the Z axis is vertically upward, the Y axis is horizontally to the right, and the X axis is horizontally forward; The feed source (200) is a horn feed source; When the feed source (200) is a horn feed source, the central axis of the horn feed source is perpendicular to the top surface of the second part (102) of the semi-compressive Luneburg lens (100); The top surface of the second part (102) is parallel to the horizontal plane.

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