Ultra-wideband miniaturized Vivaldi antenna

Abstract

The invention relates to a miniaturized Vivaldi antenna, in particular to an ultra-wideband miniaturized Vivaldi antenna. The invention aims to solve the problems that the miniaturization of the antenna cannot be realized fundamentally by using a high-dielectric-constant dielectric substrate, the antenna depends on the property of the dielectric substrate, and the radiation performance of the antenna is influenced by the dispersion effect in a millimeter wave frequency band. The antenna comprises a feed structure and two radiation structures. The two radiation structures are arranged in a herringbone shape, the feed structure is horizontally arranged on the lower portions of the two radiation structures, and the two ends of the feed structure are connected with the lower portions of the two radiation structures in an inserted mode respectively. The invention belongs to the technical field of communication.

Description

Technical Field

[0001] The invention relates to a miniaturized Vivaldi antenna, belonging to the technical field of communications. Background Art

[0002] With the rapid development of communication technology, the performance and miniaturization of communication systems are increasingly required in the fields of 5G communication, radar systems, medical imaging, etc. Ultra-wideband antenna miniaturization technology can reduce the size of the antenna without significantly reducing the performance of the antenna by rationally designing the structure and materials of the antenna, and has attracted much attention in the field of wireless communications.

[0003] The Vivaldi antenna is an end-fire traveling wave antenna with a gradient slot structure. It is widely used in many fields due to its wide bandwidth, high gain and small size, and its superior radiation characteristics and good directivity.

[0004] At present, the methods of miniaturizing Vivaldi antennas include using high dielectric constant dielectric substrates, slot loading, profile optimization, and resistor loading. However, the method of using high dielectric constant dielectric substrates cannot fundamentally achieve antenna miniaturization, which depends on the properties of the dielectric substrate, and the dispersion effect will affect the radiation performance of the antenna in the millimeter wave band; the slot loading and profile optimization methods both reduce the cutoff frequency by extending the surface current path, thereby reducing the antenna size, but this method can only reduce the antenna size to a limited extent; the resistor loading method is to load resistors at appropriate locations on the antenna to absorb reflected currents, thereby widening the bandwidth, but part of the electromagnetic waves are absorbed by the resistors, so that the antenna gain is low. Summary of the invention

[0005] The present invention aims to solve the problem that the method of using a high dielectric constant dielectric substrate cannot fundamentally achieve antenna miniaturization, relies on the properties of the dielectric substrate, and the dispersion effect affects the antenna radiation performance in the millimeter wave frequency band, and further proposes an ultra-wideband miniaturized Vivaldi antenna.

[0006] The technical solution adopted by the present invention to solve the above problems is: the present invention comprises a feeding structure and two radiating structures;

[0007] The two radiation structures are arranged in a herringbone shape, the feeding structure is arranged horizontally at the lower part of the two radiation structures, and the two ends of the feeding structure are respectively plugged into the lower part of the two radiation structures.

[0008] Further, the radiation structure includes two radiation arms, two metal pads, two plug-in structures and a dielectric plate of the radiation structure;

[0009] Two radiating arms are symmetrically arranged on the front of the dielectric plate of the radiating structure, two plug-in structures are arranged side by side in the middle of the bottom edge of the dielectric plate of the radiating structure, a rectangular groove is arranged on the bottom edge of the dielectric plate of the radiating structure, and the rectangular groove is located between the two plug-in structures;

[0010] The front of the radiation arm is provided with an elliptical gap continuous from top to bottom, the inner edge of the radiation arm is provided with a gradient line groove, the upper part of the radiation arm is provided with a radiation gap loaded with resistance, and two metal pads symmetrically arranged in the radiation gap loaded with resistance.

[0011] Further, the feeding structure includes two sector-shaped metal plates, a metal microstrip power divider, a grounded metal layer and a dielectric plate of the feeding structure;

[0012] Two fan-shaped metal plates are symmetrically arranged on the front side of the dielectric plate of the feeding structure, an inner conductor through hole is arranged in the middle of the dielectric plate of the feeding structure, a metal microstrip power divider is arranged on the front side of the dielectric plate of the feeding structure, an input end of the microstrip power divider of the metal microstrip power divider is connected with the inner conductor through hole, an output end of the microstrip power divider of the metal microstrip power divider is connected with the fan-shaped metal plate, a circular groove is arranged on the periphery of the inner conductor through hole, the dielectric plate of the feeding structure is provided with four plug-in seams, circular groove lines are arranged on both sides of the inner conductor through hole on the back side of the dielectric plate of the feeding structure, the circular groove lines are connected with the rectangular grooves through parallel groove lines, and a grounding metal layer is arranged on the back side of the dielectric plate of the feeding structure.

[0013] Furthermore, the starting point of the gradient groove line is End point The line types are:

[0014]

[0015] Where x and y(x) are the x-coordinate and y-coordinate of each point on the exponential gradient slot line respectively; W s is the width of the starting end of the exponential gradient groove; W is the end width of the gradient groove segment; L is the length of the exponential gradient groove; rad_R1 is the curvature of the exponential gradient groove.

[0016] Furthermore, the length of the metal pad is 0.8 mm, the width is 0.65 mm, and the distance between the two metal pads is 0.9 mm.

[0017] The beneficial effects of the present invention are:

[0018] 1. The ultra-wideband miniaturized Vivaldi antenna of the present invention realizes the miniaturization of the ultra-wideband antenna by loading a resistor, which greatly reduces the size of the antenna; at the same time, the elliptical gap loaded on the side of the radiation structure solves the problem of poor directivity caused by the radiation gap participating in the radiation when loading the resistor;

[0019] 2. The feeding structure of the present invention uses a microstrip power divider to replace the complex feeding structure of the traditional Vivaldi antenna. On the one hand, the feeding network is simplified, the structure is easy to process, and the reflection caused by the feeding interface is reduced. The feeding is achieved through electromagnetic coupling with the slot line; on the other hand, power distribution is achieved;

[0020] 3. The ultra-wideband miniaturized Vivaldi antenna of the present invention expands the two-dimensional Vivaldi antenna to a three-dimensional design, further reducing the longitudinal cross-section of the antenna, while making the radiation direction of the antenna more concentrated, thereby increasing the gain of the antenna in the low frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a front view of the radiation structure of the present invention;

[0022] Figure 2 is a front view of the feeding structure of the present invention;

[0023] Figure 3 is a side view of the present invention;

[0024] Figure 4 It is a standing wave ratio simulation curve diagram of the present invention;

[0025] Figure 5 is a gain simulation curve diagram of the present invention;

[0026] Figure 6 is the directional diagram of the present invention at a frequency of 1 GHz;

[0027] Figure 7 is the directional diagram of the present invention at a frequency of 12 GHz;

[0028] Figure 8 is the directional diagram of the present invention at a frequency of 19 GHz;

[0029] Figures 1 to 8 Among them, 1-radiating arm, 2-elliptical gap, 3-radiating gap loaded with resistance, 4-metal pad, 5-gradient slot line, 6-plug-in structure, 7-rectangular slot, 8-dielectric plate of radiation structure, 9-input end of microstrip power divider, 10-output end of microstrip power divider, 11-fan-shaped metal plate, 12-parallel slot line, 13-circular slot line, 14-inner conductor through hole, 15-circular slot, 16-ground metal layer, 17-plug-in seam, 18-dielectric plate of feeding structure, 19-feeding structure, 20-radiating structure. DETAILED DESCRIPTION

[0030] Specific implementation method 1: Figures 1 to 3 As shown, an ultra-wideband miniaturized Vivaldi antenna includes a feeding structure 19 and two radiating structures 20;

[0031] The two radiation structures 20 are arranged in a herringbone shape, and the feeding structure 19 is horizontally arranged at the bottom of the two radiation structures 20 . The two ends of the feeding structure 19 are respectively plugged into the bottom of the two radiation structures 20 .

[0032] The radiation structure 20 includes two radiation arms 1, two metal pads 4, two plug-in structures 6 and a dielectric plate 8 of the radiation structure;

[0033] Two radiating arms 1 are symmetrically arranged on the front of the dielectric plate 8 of the radiating structure, two plug-in structures 6 are arranged side by side in the middle of the bottom edge of the dielectric plate 8 of the radiating structure, and a rectangular groove 7 is arranged on the bottom edge of the dielectric plate 8 of the radiating structure, and the rectangular groove 7 is located between the two plug-in structures 6;

[0034] The front of the radiation arm 1 is provided with an elliptical gap 2 which is continuous from top to bottom, the inner edge of the radiation arm 1 is provided with a gradient groove line 5, the upper part of the radiation arm 1 is provided with a radiation gap 3 loaded with resistance, and two metal pads 4 which are symmetrical up and down are provided in the radiation gap 3 loaded with resistance.

[0035] The feeding structure 19 includes two fan-shaped metal plates 11, a metal microstrip power divider, a grounded metal layer 16 and a dielectric plate 18 of the feeding structure;

[0036] Two fan-shaped metal plates 11 are symmetrically arranged on the front side of the dielectric plate 18 of the feeding structure, an inner conductor through hole 14 is arranged in the middle of the dielectric plate 18 of the feeding structure, a metal microstrip power divider is arranged on the front side of the dielectric plate 18 of the feeding structure, an input end 9 of the microstrip power divider of the metal microstrip power divider is connected to the inner conductor through hole 14, an output end 10 of the microstrip power divider of the metal microstrip power divider is connected to the fan-shaped metal plate 11, a circular groove 15 is arranged on the periphery of the inner conductor through hole 14, the dielectric plate 18 of the feeding structure is provided with four plug-in seams 17, circular slot lines 13 are arranged on both sides of the inner conductor through hole 14 on the back side of the dielectric plate 18 of the feeding structure, the circular slot lines 13 are connected to the rectangular slot 7 through parallel slot lines 12, and a grounding metal layer 16 is arranged on the back side of the dielectric plate 18 of the feeding structure.

[0037] The length of the metal pad 4 is 0.8 mm, the width is 0.65 mm, and the distance between the two metal pads 4 is 0.9 mm.

[0038] like Figure 1 As shown, the position of the radiation slot 3 loaded with resistance is y=slot_point, the slot width is slot_width, the loaded resistance position is at x=res_point of the slot, the pad size is 0.8mm in length, 0.65mm in width, and the spacing is 0.9mm;

[0039] The resistance value of the loaded resistor is R1 ohm; the elliptical gap 2, such as Figure 1As shown by the dotted line on the right, the center point of the ellipse in the first part is Its major axis radius is elp_xr, and its minor axis radius is elp_yr. It is copied four times in the negative direction of the y axis according to the y axis spacing yd. The center point of the second part of the ellipse is The size is the same as the first part, with the y-axis spacing yd and the x-axis direction xd, and it is copied twice in the positive direction of the y-axis. These ellipses are cut on the radiating arm to form elliptical gaps;

[0040] The rectangular slot 7 is a rectangular slot with a length of gap_width and a width of gap_high cut into the radiation arm at the origin. The substrate material of the radiation structure is Rogers RT-duroid 6002, and the width of the rectangular substrate is W, the length is L, and the thickness is thick. The plug-in structure 6 is two rectangular dielectric plates with a length of con_length, a width of con_width, and a gap_width spacing centered at the origin, and a metal layer with a width of con_width and a length of con_high is laid at the connection with the radiation arm.

[0041] like Figure 3 As shown, two radiating structures 20 are obliquely inserted on both sides of the feeding structure 19 through a plug-in structure, and the metal layer on the plug-in structure is welded to the ground plate of the feeding structure to ensure electrical connection, forming an isosceles triangle, and the two radiating structures form an angle of F_theta; the present invention adopts a 50-ohm SMA coaxial connector for feeding, the inner conductor is connected to the microstrip power divider input terminal 9, and the outer conductor is connected to the metal ground plate 16.

[0042] Specific implementation method 2: Figures 1 to 3 As shown, based on the specific implementation mode 1, the starting point of the gradient groove line 5 is End point The line types are:

[0043]

[0044] Where x and y(x) are the x-coordinate and y-coordinate of each point on the exponential gradient slot line respectively; W s is the width of the starting end of the exponential gradient groove; W is the end width of the gradient groove segment; L is the length of the exponential gradient groove; rad_R1 is the curvature of the exponential gradient groove.

[0045] Based on CST Studio Suite electromagnetic simulation software, the parameters of the radiation structure, the feed structure and the angle between the radiation structure were optimized. The final confirmed results are as follows:

[0046] The width W of the dielectric plate 8 of the radiation structure 20 is 45 mm, the length L is 60 mm, the thickness thcik is 0.254 mm, the curvature rad_R1 of the exponential gradient slot line 5 is -0.15, the position slot_point of the resistance-loaded radiation slot 3 is 40 mm, the short axis radius elp_yr is 2.5 mm, the spacing yd is 4 mm, the spacing xd is 1 mm, the length con_length of the plug-in structure 6 is 13.6 mm, the spacing gap_width is 2.4 mm, and the dielectric plate 18 of the feeding structure 19 is The width is W, the length div_length is 41mm, the thickness is thcik, the width div_in of the input end 9 of the microstrip two-way power divider is 0.63, the width in of the output microstrip line 10 is 0.1mm, the radius sec_R of the fan-shaped metal plate 11 is 3.8mm, the central angle sec_theta is 90°, the radius coa_in of the through hole 14 is 0.635mm, the radius coa_out of the circular groove 15 is 1.15mm, the radius ref_R is 4mm, the length L_c of the parallel groove line 12 is 2.75mm, the width W s is 0.24mm, the width of the joint 17 con_width2 is 0.4mm, and the length is con_length; the radiation structure angle F_theta is 30°; the thickness of all metal layers is 0.035mm.

[0047] like Figure 4 As shown, in the simulation frequency range of 1-19.6 GHz, the voltage standing wave ratio is less than 2.1; in the frequency range of 1-13 GHz, the voltage standing wave ratio is less than 2.

[0048] like Figure 5 As shown, it can be seen that the gain is low in the low frequency band and high in the high frequency end. In the simulation frequency band 1-19.6GHz, the gain is -5dBi to 11.5dBi, and the highest gain of 11.5dBi is achieved at the frequency point of 8GHz.

[0049] like Figures 6 to 8 As shown, it can be seen that the antenna's radiation pattern has good symmetry and directivity.

[0050] In summary, the voltage standing wave ratio of the antenna is less than 2 in the range of 1-13GHz, the maximum gain within the bandwidth is 11.4dBi, and the radiation pattern has good symmetry and directivity.

[0051] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. An ultra-wideband miniaturized Vivaldi antenna, characterized in that: It comprises a feeding structure (19) and two radiating structures (20); The two radiating structures (20) are arranged in a herringbone shape, the feeding structure (19) is arranged horizontally at the bottom of the two radiating structures (20), and the two ends of the feeding structure (19) are respectively plugged into the bottom of the two radiating structures (20).

2. The ultra-wideband miniaturized Vivaldi antenna according to claim 1, characterized in that: The radiation structure (20) comprises two radiation arms (1), two metal pads (4), two plug-in structures (6) and a dielectric plate (8) of the radiation structure; Two radiating arms (1) are symmetrically arranged on the front side of a dielectric plate (8) of the radiating structure, two plug-in structures (6) are arranged side by side in the middle of the bottom edge of the dielectric plate (8) of the radiating structure, a rectangular groove (7) is provided on the bottom edge of the dielectric plate (8) of the radiating structure, and the rectangular groove (7) is located between the two plug-in structures (6); The front side of the radiation arm (1) is provided with an elliptical gap (2) which is continuous from top to bottom, the inner edge of the radiation arm (1) is provided with a gradient slot line (5), the upper part of the radiation arm (1) is provided with a radiation gap (3) for loading a resistor, and two metal pads (4) which are symmetrical up and down are provided in the radiation gap (3) for loading a resistor.

3. The ultra-wideband miniaturized Vivaldi antenna according to claim 1, characterized in that: The feeding structure (19) comprises two fan-shaped metal plates (11), a metal microstrip power divider, a grounded metal layer (16) and a dielectric plate (18) of the feeding structure; Two fan-shaped metal plates (11) are symmetrically arranged on the front side of a dielectric plate (18) of a feeding structure. An inner conductor through hole (14) is arranged in the middle of the dielectric plate (18) of the feeding structure. A metal microstrip power divider is arranged on the front side of the dielectric plate (18) of the feeding structure. An input end (9) of the metal microstrip power divider is connected to the inner conductor through hole (14). An output end (10) of the metal microstrip power divider is connected to the fan-shaped metal plate (11). A circular groove (15) is arranged on the periphery of the inner conductor through hole (14). The dielectric plate (18) of the feeding structure is provided with four plug-in seams (17). Circular slot lines (13) are arranged on both sides of the inner conductor through hole (14) on the back side of the dielectric plate (18) of the feeding structure. The circular slot lines (13) are connected to the rectangular slot (7) through parallel slot lines (12). A grounding metal layer (16) is arranged on the back side of the dielectric plate (18) of the feeding structure.

4. The ultra-wideband miniaturized Vivaldi antenna according to claim 2, characterized in that: The starting point of the gradient groove line (5) is End point The line types are: Where x and y(x) are the x-coordinate and y-coordinate of each point on the exponential gradient slot line respectively; W s is the width of the starting end of the exponential gradient groove; W is the end width of the gradient groove segment; L is the length of the exponential gradient groove; rad_R1 is the curvature of the exponential gradient groove.

5. The ultra-wideband miniaturized Vivaldi antenna according to claim 2, characterized in that: The length of the metal pad (4) is 0.8 mm, the width is 0.65 mm, and the distance between the two metal pads (4) is 0.9 mm.

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