An ultra-wideband low-profile logarithmic periodic antenna based on metamaterial structure

Abstract

The present invention discloses an ultra-wideband, low-profile log-periodic antenna based on a metamaterial structure. The antenna comprises a log-periodic antenna, a feed port, and a support mechanism located at the bottom. The metamaterial array is located between the log-periodic antenna and the feed port, and is used to achieve low-profile reflection of radiation from the dipole elements in the log-periodic antenna. The height of the ultra-wideband, low-profile log-periodic antenna based on the metamaterial structure is less than one-tenth of a wavelength. The ultra-wideband, low-profile log-periodic antenna based on the metamaterial structure disclosed herein can significantly reduce the antenna's profile and size while maintaining stable radiation characteristics.

Description

Technical Field

[0001] The present invention relates to the application field of high-gain antennas such as radio, and in particular to an ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure. Background Art

[0002] Log-periodic antennas are a hot topic in the field of ultra-wideband feed antennas. Leveraging their unique characteristics, such as folded dipole pairs and periodic gradient arrays, they can effectively improve antenna performance and reduce manufacturing costs. For example, Reference 1 ("Design of Compact Dual-Polarized Eleven Feed for Decade Bandwidth Radio Telescopes," IEEE Transactions on Antennas and Propagation, vol. 60, no. 5, pp. 2210-2218), Reference 2 ("The Circular Eleven Antenna: A New Decade-Bandwidth Feed for Reflector Antennas With High Aperture Efficiency," IEEE Transactions on Antennas and Propagation, vol. 61, no. 8, pp. 3976-3984), and Reference 3 ("On Conditions for Constant Radiation Characteristics for Log-Periodic Array Antennas," IEEE Transactions on Antennas and Propagation, vol. 58, no. 5, pp. 1521-1526) all introduce in detail new technologies such as log-periodic antennas and the new broadband feed antennas designed using them. Previous log-periodic antennas mostly used tilted antenna structures. The disadvantages of this structure are:

[0003] (1) Large volume. The thickness in Reference 1 is directly related to the frequency, and the thickness is at the level of a quarter wavelength at the lowest frequency;

[0004] (2) The processing is complex, and the structure needs to be assembled and processed using a three-dimensional structure;

[0005] (3) The phase center is unstable. Since traditional log-periodic antennas mostly use tilted antenna structures, the dipoles of different lengths located in the log-periodic antenna operate in different frequency bands and are also at different heights. Therefore, the phase center of the log-periodic antenna will change with the change of the spatial position of the working dipole, and the phase center is in an unstable state. Summary of the Invention

[0006] In response to the above technical problems, the present invention proposes an ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure, which can greatly reduce the cross-section and volume of the antenna while ensuring the stable radiation characteristics of the antenna, while ensuring the stability of the phase center.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical means:

[0008] An ultra-wideband, low-profile log-periodic antenna based on a metamaterial structure comprises a log-periodic antenna, a feed port, and a support mechanism located at the bottom. The metamaterial array is located between the log-periodic antenna and the feed port and is used to achieve low-profile reflection of radiation from dipole units in the log-periodic antenna. The height of the ultra-wideband, low-profile log-periodic antenna based on the metamaterial structure is less than one-tenth of a wavelength.

[0009] Furthermore, the metamaterial array is a periodically gradient artificial magnetic conductor, and the periodically gradient artificial magnetic conductor is arranged as a plurality of artificial magnetic conductor units arranged in a circular shape on the same plane. The area of ​​the first circular array composed of the plurality of artificial magnetic conductor units is equal to the area of ​​the second circular array composed of the plurality of folded dipole pairs on the log-periodic antenna, and the first circular array and the second circular array are arranged concentrically.

[0010] Furthermore, each of the artificial magnetic conductor units includes a first dielectric substrate, a metal floor, a metallized through-hole, and an umbrella-shaped metal patch, wherein adjacent artificial magnetic conductor units are connected through the first dielectric substrate and are arranged in a periodic gradient. The metal floor is printed on the lower surface of the first dielectric substrate to reflect electromagnetic waves. The metal floor is printed on the upper surface of the first dielectric substrate and there is a gap between the umbrella-shaped metal patches of adjacent artificial magnetic conductor units. The metallized through-hole is located inside the first dielectric substrate, the upper end of the metallized through-hole is connected to the umbrella-shaped metal patch, and the lower end of the metallized through-hole is connected to the metal floor.

[0011] Furthermore, the projection of the metallized through hole on the umbrella-shaped metal patch is located on the center line of the umbrella-shaped metal patch; and the width g of the non-metallic edge between adjacent umbrella-shaped metal patches is 0.2 to 6 mm.

[0012] Furthermore, the feeding port is located at the center below the metamaterial array, and the supporting mechanism is connected to the feeding port to support and fix the log-periodic antenna, the metamaterial array, and the feeding port.

[0013] Furthermore, each folded dipole pair on the log-periodic antenna includes a first dipole rectangular metal patch, a second dipole rectangular metal patch and a second dielectric substrate, wherein the first dipole rectangular metal patch is adjacent to and parallel to the second dipole rectangular metal patch, the first dipole rectangular metal patch and the second dipole rectangular metal patch are printed on the upper surface of the second dielectric substrate layer, and adjacent folded dipole pairs are in close contact and connection between the second dielectric substrate layers.

[0014] Furthermore, the size of the folded dipole pair on the log-periodic antenna gradually increases from the center to the circumference, and the size of the artificial magnetic conductor unit gradually increases from the center to the circumference corresponding to the size of the folded dipole pair.

[0015] The length of the umbrella-shaped metal patch is 0.5 mm to 30 mm, the width of the umbrella-shaped metal patch is 0.12 mm to 4 mm, and the diameter of the metallized through hole is 0.06 mm to 1 mm.

[0016] The first dielectric substrate is a microwave dielectric plate with a dielectric constant of 2.2 to 10.2 and a thickness of 0.1 mm to 1 mm.

[0017] The second dielectric substrate is a microwave dielectric plate with a dielectric constant of 2.2 to 10.2 and a thickness of 0.1 mm to 4 mm.

[0018] Beneficial effects:

[0019] (1) The ultra-wideband low-profile log-periodic antenna based on a metamaterial structure proposed in the present invention is different from the ordinary log-periodic antenna in that it uses a metamaterial array to achieve low-profile reflection of the radiation from the dipole unit, effectively improving the propagation path of the electromagnetic waves from the dipole, and greatly reducing the height of the log-periodic antenna. The antenna height is reduced from the original quarter wavelength to less than one tenth wavelength, and the phase center is stable.

[0020] Reason for reducing height: Traditional log-periodic antennas need to maintain a distance of one-quarter wavelength between the metal ground and the antenna to achieve isotropic reflection of electromagnetic waves. Therefore, the antenna height is about one-quarter wavelength. The ultra-wideband low-profile log-periodic antenna based on metamaterial structure proposed in the present invention adopts a metamaterial structure. While realizing electromagnetic waves, the height of this structure is no more than one-tenth of the wavelength. Therefore, the height of the log-periodic antenna is significantly reduced. Reason for phase center stability: Since traditional log-periodic antennas mostly adopt an inclined antenna structure, the dipoles of different lengths in the log-periodic antenna are at different heights while working in different frequency bands. Therefore, the phase center of the log-periodic antenna will change with the change of the spatial position of the working dipole, and the phase center is in an unstable state. In this structure, a planar metamaterial array is used to achieve isotropic reflection of electromagnetic waves. Therefore, the log-periodic antenna is converted from a three-dimensional structure to a planar structure. Although the working dipole will change when working in different frequency bands, since all dipoles are in the same plane, the phase center is stable.

[0021] (2) The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure proposed in the present invention uses a microwave dielectric plate, has a simple structure, is easy to process, has relatively small weight and size, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A three-dimensional diagram of the ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure of the present invention;

[0023] Among them, 1 is the logarithmic periodic antenna; 2 is the periodic gradient artificial magnetic conductor; 3 is the feeding port; 4 is the support machine;

[0024] Figure 2 A top view of the ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to the present invention;

[0025] Where g is the width of the non-metallic edge;

[0026] Figure 3 A side view of the ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure of the present invention;

[0027] Wherein, h1 is the thickness of the first dielectric substrate; h2 is the thickness of the second dielectric substrate;

[0028] Figure 4 A top view of the logarithmic periodic antenna of the ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure of the present invention;

[0029] Among them, 5 is a folded dipole pair;

[0030] Figure 5A top view of the periodically gradient artificial magnetic conductor of the ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure of the present invention;

[0031] Among them, 6 is an artificial magnetic conductor unit;

[0032] Figure 6 A three-dimensional diagram of an artificial magnetic conductor unit of an ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure of the present invention;

[0033] Wherein, 7 is the first dielectric substrate; 8 is the metal floor; 9 is the metallized through hole; 10 is the umbrella-shaped metal patch; d is the diameter of the metallized through hole; w is the width of the umbrella-shaped metal patch; L is the length of the umbrella-shaped metal patch;

[0034] Figure 7 Schematic diagram of the structure of the folded dipole unit of the present invention;

[0035] Wherein, 11 is the first dipole rectangular metal patch; 12 is the second dipole rectangular metal patch; 13 is the second dielectric substrate; Wy1 is the side length of the first dipole rectangular metal patch; Wy2 is the side length of the second dipole rectangular metal patch; Wx1 is the width of the first dipole rectangular metal patch; Wx2 is the width of the second dipole rectangular metal patch; Dy is the length of the U-shaped slot; Dx is the width of the U-shaped slot;

[0036] Figure 8 This is a reflection coefficient curve of the ultra-wideband low-profile logarithmic periodic antenna based on the metamaterial structure of the present invention;

[0037] Figure 9 The E-plane main polarization and cross-polarization patterns of the ultra-wideband low-profile logarithmic periodic antenna based on the metamaterial structure of the present invention;

[0038] Figure 10 These are the H-plane main polarization and cross-polarization patterns of the ultra-wideband low-profile logarithmic periodic antenna based on the metamaterial structure of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings. Example

[0040] Combine Figures 1 to 5As shown, the ultra-wideband low-profile logarithmic periodic antenna consists of four parts, including a logarithmic periodic antenna 1, a periodic gradient artificial magnetic conductor 2, a feed port 3 and a support mechanism 4; wherein the logarithmic periodic antenna 1 is composed of four groups of circularly arranged folded dipole pairs 5, with a total of 8 folded dipole pairs 5, and the size gradually increases from the center of the circle to the circumference; the periodic gradient artificial magnetic conductor 2 is composed of four groups of circularly arranged artificial magnetic conductor units 6, with a total of 8 artificial magnetic conductor units 6, and the size gradually increases from the center of the circle to the circumference. The area of ​​the circular array formed by the logarithmic periodic antenna 1 is equal to the circular array formed by the periodic gradient artificial magnetic conductor 2, and the projections of the two circles are concentric.

[0041] like Figure 6 As shown, the artificial magnetic conductor unit 6 of the present invention is composed of four parts, including a first dielectric substrate 7, a metal floor 8, a metalized through hole 9 and an umbrella-shaped metal patch 10; wherein, the first dielectric substrate 7 has a dielectric constant εr of 2.2 and a thickness ha of 0.2 mm.

[0042] like Figure 7 As shown, the folded dipole pair 5 consists of three parts, including a first dipole rectangular metal patch 11, a second dipole rectangular metal patch 12, and a second dielectric substrate 13. The dielectric constant εr of the second dielectric substrate 13 is 3.55 and the thickness h is 2 mm.

[0043] The structures and sizes of the eight artificial magnetic conductor units 6 are the same. For any one of the artificial magnetic conductor units 6, such as the sixth umbrella-shaped metal patch, the length L of the umbrella-shaped metal patch 10 is 10 mm, the width W of the umbrella-shaped metal patch 10 is 0.4 mm, and the diameter d of the metallized through hole 9 is 0.2 mm.

[0044] For the sixth dipole, the upper layer loaded with the first dipole rectangular metal patch 11 and the second dipole rectangular metal patch 12 has side lengths Wy1 and Wy2 of 9.5 mm and 10 mm respectively, widths Wx1 and Wx2 of 0.36 mm and 0.38 mm, and the length Dy of the U-shaped groove is 9.1 mm and the width Dx is 0.7 mm.

[0045] From the above analysis, it can be seen that the ultra-wideband low-profile logarithmic periodic antenna based on the metamaterial structure of the present invention has an overall thickness of 2.2 mm, which is 0.05 wavelength.

[0046] Depend on Figure 8 It can be seen that the ultra-wideband low-profile log-periodic antenna based on the metamaterial structure of the present invention has a reflection coefficient of less than -10 dB and can cover a frequency band of 7-14 GHz.

[0047] like Figure 9 and Figure 10In the frequency band of 7-14GHz, the cross-plan of the antenna radiation pattern is less than -10dB in the entire frequency band. At the same time, the beam width can be kept consistent throughout the entire frequency band, and its -10dB beam width is basically controlled within the angle range of -30° to 30° in the entire frequency band.

[0048] It can be seen from the above that the ultra-wideband low-profile logarithmic periodic antenna based on the metamaterial structure of the present invention can effectively achieve the antenna characteristics of low-profile ultra-wideband.

[0049] In addition to the effects of the present disclosure as described above, further advantages and features of the present disclosure will be clearly understood by those skilled in the art from the above description of the present disclosure.

[0050] It is obvious to those skilled in the art that the present disclosure is not limited to the above embodiments and drawings, and that various substitutions, modifications, and variations may be made in the present disclosure without departing from the spirit or scope of the present disclosure. Therefore, the scope of the present disclosure is defined by the appended claims, and it is intended that all variations or modifications derived from the meaning, scope, and equivalents of the claims fall within the scope of the present disclosure.

[0051] The various embodiments described above can be combined to provide further embodiments.

[0052] These and other changes can be made to the present embodiment in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible implementations, along with the full scope of equivalents to which such claims are entitled. Therefore, the claims are not limited by the disclosure.

Claims

1. An ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure, comprising a logarithmic periodic antenna (1), a feed port (3) and a support mechanism (4) located at the bottom, characterized in that: It also includes a metamaterial array, which is located between the log-periodic antenna and the feed port (3) and is used to achieve low-profile reflection of radiation from the dipole unit in the log-periodic antenna (1). The height of the ultra-wideband low-profile log-periodic antenna based on the metamaterial structure is less than one-tenth of the wavelength; The metamaterial array is a periodically gradient artificial magnetic conductor (2), and the periodically gradient artificial magnetic conductor (2) is configured as a plurality of artificial magnetic conductor units (6) arranged in a circular pattern on the same plane. The area of ​​a first circular array composed of the plurality of artificial magnetic conductor units (6) is equal to the area of ​​a second circular array composed of the plurality of folded dipole pairs (5) on the log-periodic antenna (1), and the first circular array and the second circular array are concentrically arranged.

2. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 1, characterized in that: Each of the artificial magnetic conductor units (6) comprises a first dielectric substrate (7), a metal floor (8), a metalized through hole (9) and an umbrella-shaped metal patch (10), wherein adjacent artificial magnetic conductor units (6) are connected via the first dielectric substrate (7) and are arranged in a periodic gradient; the metal floor (8) is printed on the lower surface of the first dielectric substrate (7) to reflect electromagnetic waves; and gaps exist between the umbrella-shaped metal patches (10) of adjacent artificial magnetic conductor units (6) printed on the upper surface of the first dielectric substrate (7); the metalized through hole (9) is located inside the first dielectric substrate (7); the upper end of the metalized through hole (9) is connected to the umbrella-shaped metal patch (10), and the lower end of the metalized through hole (9) is connected to the metal floor (8).

3. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 2, characterized in that: The projection of the metallized through hole (9) on the umbrella-shaped metal patch (10) is located on the center line of the umbrella-shaped metal patch (10); the width g of the non-metallic edge between adjacent umbrella-shaped metal patches is 0.2 to 6 mm.

4. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 1, characterized in that: The feeding port (3) is located at the center below the metamaterial array, and the supporting mechanism (4) is connected to the feeding port (3) to achieve support and fixation of the logarithmic periodic antenna (1), the metamaterial array, and the feeding port (3).

5. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 1, characterized in that: Each folded dipole pair (5) on the log-periodic antenna (1) comprises a first dipole rectangular metal patch (11), a second dipole rectangular metal patch (12), and a second dielectric substrate (13), wherein the first dipole rectangular metal patch (11) is adjacent to and parallel to the second dipole rectangular metal patch (12), the first dipole rectangular metal patch (11) and the second dipole rectangular metal patch (12) are printed on the upper surface of the second dielectric substrate (13), and adjacent folded dipole pairs (5) are in close contact and connection between the second dielectric substrate (13).

6. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 1, characterized in that: The size of the folded dipole pair (5) on the log-periodic antenna (1) gradually increases from the center of the circle to the circumference, and the size of the artificial magnetic conductor unit (6) gradually increases from the center of the circle to the circumference corresponding to the size of the folded dipole pair (5).

7. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 2, characterized in that: The length of the umbrella-shaped metal patch (10) is 0.5 mm to 30 mm, the width of the umbrella-shaped metal patch (10) is 0.12 mm to 4 mm, and the diameter of the metallized through hole (9) is 0.06 mm to 1 mm.

8. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 2, characterized in that: The first dielectric substrate (7) is a microwave dielectric plate with a dielectric constant of 2.2 to 10.2 and a thickness of 0.1 mm to 1 mm.

9. The ultra-wideband low-profile logarithmic periodic antenna based on a metamaterial structure according to claim 5, characterized in that: The second dielectric substrate (13) is a microwave dielectric plate with a dielectric constant of 2.2 to 10.2 and a thickness of 0.1 mm to 4 mm.

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