Ultra-wideband galvanic couple antenna loaded with artificial magnetic conductor

Abstract

The invention provides an ultra-wideband galvanic couple antenna loaded with an artificial magnetic conductor, and the antenna comprises a radiation patch layer (1) which is used for generating natural impedance gradual change; the AMC layer (2) is located under the radiation patch, is parallel to the radiation patch and is used for reducing the height of the profile of the antenna in an in-phase reflection mode; the grounding plate (4) is positioned under the AMC layer and is used for converting bidirectional radiation into unidirectional radiation; the electric wall (3) is vertically connected between the radiation patch and the grounding plate and is used for equivalently forming mirror image electric dipoles on two sides of the radiation patch; the absorption resistors (5, 6, 7 and 8) are symmetrically arranged between the outer edge of the radiation patch and the electric wall and are used for eliminating tail end reflection current so as to broaden the bandwidth; and the coaxial line penetrates through the grounding plate and the AMC layer and then is connected to two inner side end points of the radiation patch, and is used for realizing balanced feed and keeping a directional diagram symmetrical. The novel curve type radiation patch design is adopted, natural impedance gradual change is achieved, and an absorption resistor is loaded at the tail end to reduce tail end reflection.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to an ultra-wideband electrocouple antenna loaded with an artificial magnetic conductor. Background Technology

[0002] Ultra-wideband antenna technology has been widely used in radar detection and short-range communication in recent years. Traditional ultra-wideband antenna designs mainly employ log-periodic antennas and Vivaldi antennas, but these antennas generally suffer from large size and high profile. To reduce the antenna profile, researchers have proposed several solutions, including:

[0003] (1) A high dielectric constant substrate is used;

[0004] (2) Introduce short-circuit pins or short-circuit wall structures;

[0005] (3) Use artificial electromagnetic materials such as frequency selective surface (FSS) or electromagnetic bandgap structure (EBG).

[0006] The paper "Wideband AMC Surface and Applications to Low Profile CircularlyPolarized Slot Antennas" presented at the 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) proposes an ultra-wideband antenna loaded with artificial magnetic conductors (AMCs), applied to a low-profile circularly polarized slot antenna, achieving unidirectional radiation and wideband performance. However, it still has shortcomings. The antenna loaded with artificial magnetic conductors (AMCs) cannot achieve a wide bandwidth, which may still be insufficient for ultra-wideband applications in detection radar; and the radiation characteristics are unstable, with a tilted radiation pattern. A secondary technical problem is that the AMC element is complex in form, making it inconvenient to manufacture. Summary of the Invention

[0007] To address the above technical problems, this invention proposes an ultra-wideband electrocouple antenna loaded with an artificial magnetic conductor. The specific technical solution is as follows:

[0008] An ultrawideband electrocouple antenna loaded with an artificial magnetic conductor, comprising:

[0009] Radiation patch layer, used to generate a natural impedance gradient;

[0010] The AMC layer, located directly below and parallel to the radiating patch, is used to reduce the antenna profile height using in-phase reflection.

[0011] The ground plane located directly below the AMC layer is used to convert bidirectional radiation into unidirectional radiation;

[0012] An electric wall vertically connected between the radiating patch and the ground plane is used to form equivalent mirror electric dipoles on both sides of the radiating patch;

[0013] Absorption resistors symmetrically arranged between the outer edge of the radiating patch and the electric wall are used to eliminate end reflection current and broaden the bandwidth;

[0014] The coaxial cable passes through the ground plane and the AMC layer and connects to the two inner ends of the radiating patch to achieve balanced feeding and maintain pattern symmetry.

[0015] The present invention has the following beneficial effects:

[0016] This invention employs a novel curved radiating patch design to achieve a gradual change in natural impedance and adds an absorption resistor at the end to reduce end reflection. A square AMC unit is used to achieve a wide in-phase reflection bandwidth layer, thus maintaining a low profile over a wide frequency band. The antenna gain is improved through the loading of the back cavity structure; simultaneously, the introduction of the AMC layer also improves the antenna gain. The use of two coaxial balanced feeds solves the problem of pattern asymmetry compared to existing technologies.

[0017] This invention replaces the traditional quarter-wavelength high metal reflector with an artificial magnetic conductor (AMC) surface, utilizing its in-phase reflection characteristics to significantly reduce the antenna profile height while maintaining radiation efficiency, thus achieving a low-profile antenna structure. The AMC element is square in shape, with a simple structure and a wide in-phase bandwidth.

[0018] This invention offers scalable bandwidth, maintaining stable antenna performance across a wider frequency band through end-loaded resistors. It also enhances radiation directivity; the back cavity composed of a ground plane and electric walls enables unidirectional radiation, improving the front-to-back ratio of the radiation pattern and the main beam gain, thus enhancing radiation characteristics. Furthermore, this invention boasts a compact structure; the electric wall loading forms a mirrored electric dipole, further reducing the overall antenna size and meeting the demands of miniaturized devices.

[0019] This invention determines the shape parameters of the patch curve so that the voltage standing wave ratio (VSWR) of the antenna is less than 2 in the entire frequency band of 100-300MHz. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the antenna of the present invention;

[0021] Figure 2 This is the standing wave curve of the antenna of the present invention;

[0022] Figure 3 A schematic diagram showing the reduced cross-section of an artificial magnetic conductor;

[0023] Figure 4 This is a schematic diagram of the equivalent source based on the mirror principle.

[0024] Figure 5 The radiation patterns of the antenna of this invention at four frequency points are shown.

[0025] Figure 6 For parameters The corresponding VSWR curve when the change occurs;

[0026] Figure 7 For parameters The corresponding VSWR curve when the change occurs;

[0027] Figure 8 This is the VSWR curve corresponding to the change of parameter m. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, the invention adopts the following technical solutions.

[0029] like Figure 1As shown, this invention provides an ultra-wideband electrocouple antenna with an artificial magnetic conductor, comprising a radiating patch layer 1, an AMC layer 2, an electric wall 3, a ground plane 4, four absorption resistors 5, 6, 7, and 8, and two coaxial lines. The radiating patch layer 1 is composed of two symmetrical curved metal sheets with a certain spacing between them, backing onto a rectangular dielectric substrate. The AMC layer 2 is located at a fixed distance directly below the radiating patch layer 1, and is composed of 9×5 square metal sheets arranged horizontally and vertically with a certain distance between the units, the array backing onto the rectangular dielectric substrate to form the AMC layer 2. The ground plane 4 is rectangular and located at a fixed distance directly below the AMC layer 2. The electric wall 3 is perpendicular to the plane of the ground plane 4, and is rectangular in shape. Its upper edge connects to the two short edges of the dielectric substrate backing onto the radiating patch layer 1, and its lower edge connects to the two short edges of the ground plane 4. One end of each of the four absorption resistors 5, 6, 7, and 8 is connected to four points on the outer edge of the radiating patch, and the other end is connected to the two electric walls 3 on either side. The two coaxial cables are connected at their lower ends to the ground plane 4, pass through the AMC layer 2, and connect upwards to the two inner endpoints of the radiating patch layer 1. The dielectric substrates used for the radiating patch layer 1 and the AMC layer 2 are both FR-4 material with a dielectric constant of 4.3 and a thickness of 2 mm. The metal sheets of the radiating patch layer 1, the metal sheets of the AMC layer 2, the electrical barrier 3, and the ground plane 4 are made of copper with a thickness of 35 μm. The resistance values ​​of the four absorption resistors 5, 6, 7, and 8 are all 125 ohms. The dielectric substrate dimensions of the radiating patch layer 1 and the AMC layer 2 are both 1180 mm × 550 mm × 2 mm; the distance between the radiating patch layer 1 and the AMC layer 2 is 40 mm, and the distance between the AMC layer 2 and the ground plane 4 is 160 mm; the square side length of the metal sheet in the AMC layer 2 is 116 mm, and the spacing between the metal sheets is 120 mm; the edge curve equation of the metal sheet in the radiating patch layer 1 satisfies the following curve equation:

[0030] ;

[0031] in, , , , , Parameters used to modify the shape of the curve.

[0032] The equation coefficients are: = =m=7, =0.8, = =1.6.

[0033] The equations transformed into rectangular coordinates are:

[0034] ;

[0035] Where x and y are the initial x and y coordinates of the curve, This represents the horizontal offset of the curve. X represents the vertical offset of the curve, and X and Y are the horizontal and vertical coordinates of the curve after the offset. Let x be the angle between the line connecting a point on the curve to the center of the circle and the x-axis. Let be the distance from a point on the curve to the center of the circle. This is the horizontal magnification factor of the curve in the left semicircle. This represents the horizontal magnification factor of the curve in the right semicircle. is the vertical magnification factor of the curve; where, =-33mm, =28mm, =0.23, =0.35, =0.3.

[0036] When the antenna is working, the excitation is input through the feed port of the Wilkinson power divider. After the signal is split into two equal amplitudes by the power divider, the excitation is transmitted to the feed balun at the end of the power divider. After being transmitted through the feed balun, the signal finally reaches the tightly coupled antenna element and radiates outward to form a radiated electromagnetic wave.

[0037] In tightly coupled antenna array design, metal reflectors are an important component. Figure 3 In this scenario, part of the electromagnetic waves radiated by the antenna array radiates upward into the half-space, while the other part propagates towards the reflector. At the center frequency, the electromagnetic wave that travels a quarter wavelength to reach the ideal conductor PEC has a 90° phase difference relative to the electromagnetic wave at the antenna array. After reflection by the PEC reflector, the reflected wave on the PEC reflector surface has a 180° phase difference compared to the incident wave at the same location. After traveling another quarter wavelength, the electromagnetic wave that originally radiated downward into the half-space reaches the antenna array plane, having now traveled exactly 360°, and is in phase with the originally upward-radiated wave. If the center frequency PEC reflector at the quarter-wavelength distance is replaced with an artificial magnetic conductor close to the plane of the oscillator, the downward-propagating electromagnetic wave immediately reaches the plane of the artificial magnetic conductor after leaving the plane of the oscillator. Within the in-phase reflection bandgap of the artificial magnetic conductor, the originally downward-propagating electromagnetic wave undergoes in-phase reflection and is superimposed in phase with the originally upward-radiated electromagnetic wave.

[0038] The above analysis shows that within the in-phase reflection bandgap, the artificial magnetic conductor and the reflector at a quarter-wavelength of the center frequency of the array have the same effect. The artificial magnetic conductor within the bandgap can simulate the performance of an ideal magnetic conductor, and is closer to ideal conditions than the reflector at a quarter-wavelength of the center frequency of the array.

[0039] The mirror principle states that the magnetic field generated by any charge in the space above an infinitely large, ideal conducting plate is electrically equivalent to the electric field generated by the original charge superimposed with the electric field generated by its mirror image. When a field source approaches an infinitely large, ideal conducting plane, the radiation pattern differs from that in free space due to the influence of the wall. According to electromagnetic theory, this radiation can be considered as a composite field produced by the field source and a "virtual source" (i.e., its mirror image) in a symmetrical position. Figure 4 In this design, when the positive and negative poles are placed perpendicular to an ideal conducting plate, positive and negative poles with the same current direction are equivalently generated below the plate. When placed horizontally, positive and negative poles with opposite current directions are equivalently generated below the plate. In this case, the equivalent size of the antenna is twice its actual size. This invention utilizes this principle, by loading electric walls, to create mirror-image electric dipoles on both sides, thereby reducing the actual horizontal size of the dipole antenna operating at half wavelength.

[0040] When the ultra-wideband antenna with AMC is in operation, the signal is received at the ends of the two coaxial lines and transmitted from bottom to top to the radiating patch layer 1. According to the mirror principle, the presence of the vertical electric walls 3 on both sides creates an equivalent mirror image of the radiating patch layer 1 outside the left and right sides, thereby reducing the actual length of the antenna. The ground plane 4 changes the antenna's radiation pattern from bidirectional to unidirectional radiation, improving the main beam gain. The AMC layer 2 acts as an in-phase reflector; compared to ground plane 4 alone, the introduction of the AMC layer 2 significantly reduces the antenna's profile height while improving the broadband characteristics and radiation gain of the antenna of the same size. The presence of the four absorption resistors 5, 6, 7, and 8 eliminates the end current of the radiating patch, reduces reflected echoes, and improves matching characteristics.

[0041] Figure 2 The figure shows the standing wave (VSWR) curve of the antenna of this invention. In the figure, the horizontal axis represents the frequency variable, with the unit being MHz; the vertical axis represents the ratio of the reflected wave to the incident wave. The VSWR of the antenna of this invention is <2 in the 100-300MHz frequency band. Figure 5 The antenna radiation patterns at four frequency points are shown below. Figure 5 As can be seen from (a), (b), (c), and (d), within the 100-300MHz range, the main beam direction of the antenna is perpendicular to the plane of the radiating patch, and the radiation pattern is stable. At 400MHz, the antenna lobes split, and the signals received from the side lobes in the main radiation direction cause significant interference to the radar system, rendering the antenna unable to function properly. Therefore, the antenna impedance bandwidth and radiation pattern bandwidth designed in this invention are 100-300MHz.

[0042] The shape of the radiating patch curve directly affects the current distribution on the radiating patch surface, thus affecting the impedance bandwidth of the antenna. The curve shape is determined by parameters... , , , , Confirm. Regarding the parameters... , , , , Optimization analysis yielded the following results:

[0043] Figure 6 express: When the value is increased, the matching performance is improved. When = 0.8, VSWR < 2 across the entire frequency band, as As the value continues to increase, the matching performance deteriorates at high frequencies.

[0044] Figure 7 Indicates: In = hour, When the value is increased, the low-frequency matching performance is improved. When =1.6, VSWR < 2 across the entire frequency band, as As the frequency continues to increase, the matching performance deteriorates at low frequencies.

[0045] Figure 8 express: = Marked as m, the matching performance is better when m is an odd number than when m is an even number. When m=5, the high-frequency matching performance is slightly worse, while when m=7, VSWR<2 across the entire frequency band.

[0046] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0047] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0048] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0049] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0050] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0051] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An ultra-wideband electrocouple antenna loaded with an artificial magnetic conductor, characterized in that, include: Radiation patch layer, used to generate a natural impedance gradient; An artificial magnetic conductor (AMC) layer located directly below and parallel to the radiating patch is used to reduce the antenna profile height via in-phase reflection. The ground plane located directly below the AMC layer is used to convert bidirectional radiation into unidirectional radiation; An electric wall vertically connected between the radiating patch and the ground plane is used to form equivalent mirror electric dipoles on both sides of the radiating patch; Absorption resistors symmetrically arranged between the outer edge of the radiating patch and the electric wall are used to eliminate end reflection current and broaden the bandwidth; The coaxial cable passes through the ground plane and the AMC layer and connects to the two inner ends of the radiating patch to achieve balanced feeding and maintain pattern symmetry.

2. The ultra-wideband electrocouple antenna with an artificial magnetic conductor according to claim 1, characterized in that, The radiation patch layer consists of two symmetrical curved metal sheets with a certain spacing between them, and is backed by a rectangular dielectric substrate.

3. The ultra-wideband electrocouple antenna with an artificial magnetic conductor according to claim 1, characterized in that, The AMC layer is located at a fixed distance directly below the radiating patch layer. It is composed of square metal sheets arranged horizontally and vertically, with a certain distance between the units. The array is backed by a rectangular dielectric substrate to form the AMC layer.

4. The ultra-wideband electrocouple antenna with an artificial magnetic conductor according to claim 1, characterized in that, The grounding plate is rectangular in shape and is located at a fixed distance directly below the AMC layer.

5. The ultra-wideband electrocouple antenna with an artificial magnetic conductor according to claim 1, characterized in that, The electric wall is perpendicular to the plane of the ground plane. The electric wall is rectangular in shape, with its upper edge connected to the two short edges of the dielectric substrate behind the radiation patch layer, and its lower edge connected to the two short edges of the ground plane.

6. The ultra-wideband electrocouple antenna with an artificial magnetic conductor according to claim 1, characterized in that, Four absorption resistors are set. One end of each absorption resistor is connected to one of the four points on the outer edge of the radiation patch, and the other end is connected to the two electric walls.

7. The ultra-wideband electrocouple antenna with an artificial magnetic conductor according to claim 1, characterized in that, Two coaxial cables are used. The lower end of the coaxial cable is connected to the ground plane, and it passes through the AMC layer and connects upward to the two inner ends of the radiation patch layer.

8. An ultra-wideband electrocouple antenna with an artificial magnetic conductor loaded according to claim 2 or 3, characterized in that, The dielectric substrates used for the radiation patch layer and the AMC layer are both made of FR-4 material, which has a dielectric constant of 4.3 and a thickness of 2 mm.

9. An ultra-wideband electrocouple antenna with an artificial magnetic conductor loaded according to claim 2 or 3, characterized in that, The metal sheets of the radiation patch layer, the metal sheets of the AMC layer, the electric wall, and the ground plane are made of copper with a thickness of 35 μm.

10. An ultra-wideband electrocouple antenna with an artificial magnetic conductor loaded according to claim 2, characterized in that, The equation for the edge curve of the metal sheet in the radiation patch layer is: ； in, , , , , These are parameters used to modify the shape of the curve; among them, = =7, =0.8, = =1.6; The equations transformed into rectangular coordinates are: ； Where x and y are the initial x and y coordinates of the curve, This represents the horizontal offset of the curve. X represents the vertical offset of the curve, and X and Y are the horizontal and vertical coordinates of the curve after the offset. Let x be the angle between the line connecting a point on the curve to the center of the circle and the x-axis. Let be the distance from a point on the curve to the center of the circle. This is the horizontal magnification factor of the curve in the left semicircle. This represents the horizontal magnification factor of the curve in the right semicircle. is the vertical magnification factor of the curve; where, =-33mm, =28mm, =0.23, =0.35, =0.3.

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