A low-profile broadband array antenna

Abstract

The invention discloses a low-profile broadband array antenna, belonging to the field of antenna technology; wherein the oscillator unit is a parallel double-line feeding off-plane printed dipole, which is printed on both sides of a microwave dielectric plate. The synthetic network is a broadband parallel double-line synthetic feeding network based on exponential line impedance transformation. The printed dipole and the synthetic network are integrated on the same microwave dielectric plate. The periodic loading layer adopts a periodic square metal coating printed on the microwave dielectric plate, and the square size is less than 0.08 wavelength of the center frequency. The invention has excellent electrical performance and low-profile characteristics.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a low-profile broadband array antenna. Background Art

[0002] Dipole antenna is one of the most typical forms of antenna, especially dipole antenna with reflector. It is widely used in satellite communication, mobile phone communication and electronic countermeasure due to its wide bandwidth, good directional performance, simple and reliable structure and other advantages.

[0003] At present, the commonly used dipole antenna forms mainly include plate-line structure dipole antenna, cross-shaped dipole antenna and printed dipole antenna. Plate-line structure dipole antenna is mainly composed of antenna dipole, plate-line balun and metal reflective bottom plate. It has a simple and reliable structure and is mainly used for single-line polarization. Cross-shaped dipole antenna is mainly composed of cross dipole, metal bottom plate and feeding cable. It has realized dual-line polarization and circular polarization. It is mainly used in base station antennas. The vibrator can be a metal vibrator or a dielectric printed structure. Printed dipole antenna has gradually developed with the widespread use of microwave dielectric boards. It is mainly composed of printed dipole, stripline / microstrip line balun and metal reflector. The dipole and antenna balun are integrated on the same microwave dielectric board.

[0004] The above three antennas require connectors or RF cables as outputs. When used as array antenna units, they cannot be integrated with the antenna synthesis network. External cables and power dividers are required to achieve this synthesis. The antenna synthesis network is complex, the loss is large, and the overall height of the antenna is very high. To solve this problem, a planar printed dipole antenna has emerged. The main difference between the flat printed dipole antenna and the above three antennas is that the antenna dipole adopts a planar structure and the synthesis network adopts a parallel two-wire network. Through this design, the antenna dipole and the feeding network are integrated on the same microwave dielectric board, solving the problem that the feeding network of the above three antennas cannot be integrated. However, since the impedance of the dipole antenna is related to the distance from the metal reflective bottom plate of the antenna, these three dipole antennas need to achieve good impedance matching characteristics within a relative bandwidth of 66.7%, and the height is usually about 0.2 low-frequency wavelengths. In this way, when used in low-frequency bands, especially when used at frequencies below the L band, the antenna profile is high. Summary of the invention

[0005] In view of this, the present invention provides a low-profile broadband array antenna. The antenna has excellent electrical performance and low-profile characteristics.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A low-profile broadband array antenna comprises a coaxial feeding interface, and also comprises a dielectric matching layer, a periodic loading layer and a metal floor stacked in sequence; an air layer is provided between the dielectric matching layer and the periodic loading layer, and between the periodic loading layer and the metal floor;

[0008] The dielectric matching layer includes a first microwave dielectric substrate; a vibrator unit is provided on the first microwave dielectric substrate, and the vibrator unit is a parallel double-line feeding off-plane printed dipole; the parallel double-line feeding off-plane printed dipole includes a synthetic network, and the synthetic network is a broadband parallel double-line synthetic feeding network based on exponential line impedance transformation;

[0009] The periodic loading layer comprises a second microwave dielectric substrate, on which square metal coatings arranged in a rectangular array are provided;

[0010] The inner conductor and the outer conductor of the coaxial feeding interface are respectively connected to the main path of the upper surface synthetic network or the main path of the lower surface synthetic network of the first microwave dielectric board.

[0011] Furthermore, the broadband parallel two-wire synthetic feeding network based on exponential line impedance transformation is a one-to-eight feeding network, and the parallel two-wire feeding off-plane printed dipole includes a metal patch; the projections of the feeding networks on the upper and lower surfaces of the first microwave dielectric board overlap; the branch ends of the feeding network are all connected to the metal patches, and the metal patches are located on one side of the branch ends; the metal patches corresponding to the upper and lower surfaces of the first microwave dielectric board are respectively located on the opposite sides of the branch ends.

[0012] Furthermore, the side length of the square metal coating is less than 0.08 times the wavelength of the center frequency.

[0013] Furthermore, the main path of the upper surface feeding network of the first microwave dielectric board is connected with a rectangular matching branch, and the inner conductor of the coaxial feeding interface is connected with the main path of the upper surface synthesis network of the first microwave dielectric board through the rectangular matching branch; the main path of the lower surface feeding network of the first microwave dielectric board is connected with a trapezoidal matching branch, and the outer conductor of the coaxial feeding interface is connected with the main path of the lower surface synthesis network of the first microwave dielectric board through the trapezoidal matching branch.

[0014] Furthermore, the trapezoidal matching branch is located directly below the rectangular matching branch.

[0015] The beneficial effects of the above technical solution of the present invention are:

[0016] 1. The present invention adopts a periodic loading layer to reduce the height of the antenna, which has better concealment.

[0017] 2. The present invention provides air layers between the dielectric matching layer and the periodic loading layer and between the periodic loading layer and the metal floor, so that the antenna is lighter.

[0018] 3. The present invention reduces the height of the antenna by 50% of the original height, the antenna has a low profile and a more stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 Schematic diagram of the structure of the lower surface of the first microwave dielectric plate.

[0021] Figure 3 yes Figure 1 Schematic diagram of the structure of the upper surface of the second microwave dielectric plate.

[0022] In the figure, 1, a first microwave dielectric board, 2, a second microwave dielectric board, 3, a metal floor, 4, a feeding network, 5, a metal patch, 6, a rectangular matching branch, and 7, a trapezoidal matching branch. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] A low-profile broadband array antenna comprises a coaxial feeding interface, and also comprises a dielectric matching layer, a periodic loading layer and a metal floor 3 stacked in sequence; an air layer is provided between the dielectric matching layer and the periodic loading layer, and between the periodic loading layer and the metal floor;

[0026] The dielectric matching layer comprises a first microwave dielectric substrate 1; a vibrator unit is arranged on the first microwave dielectric substrate, and the vibrator unit is a parallel double-line feeding off-plane printed dipole; the parallel double-line feeding off-plane printed dipole comprises a synthetic network, and the synthetic network is a broadband parallel double-line synthetic feeding network based on exponential line impedance transformation;

[0027] The periodic loading layer comprises a second microwave dielectric substrate 2, on which square metal coatings arranged in a rectangular array are provided;

[0028] The inner conductor and the outer conductor of the coaxial feeding interface are respectively connected to the main path of the upper surface synthetic network or the main path of the lower surface synthetic network of the first microwave dielectric board.

[0029] Furthermore, the broadband parallel two-wire synthetic feeding network based on exponential line impedance transformation is a one-to-eight feeding network 4, and the parallel two-wire feeding off-plane printed dipole includes a metal patch 5; the projections of the feeding networks on the upper and lower surfaces of the first microwave dielectric board overlap; the branch ends of the feeding network are all connected to the metal patches, and the metal patches are located on one side of the branch ends; the metal patches corresponding to the upper and lower surfaces of the first microwave dielectric board are respectively located on the opposite sides of the branch ends.

[0030] Furthermore, the side length of the square metal coating is less than 0.08 times the wavelength of the center frequency.

[0031] Furthermore, the main path of the upper surface feeding network of the first microwave dielectric board is connected with a rectangular matching branch 6, and the inner conductor of the coaxial feeding interface is connected with the main path of the upper surface synthesis network of the first microwave dielectric board through the rectangular matching branch; the main path of the lower surface feeding network of the first microwave dielectric board is connected with a trapezoidal matching branch 7, and the outer conductor of the coaxial feeding interface is connected with the main path of the lower surface synthesis network of the first microwave dielectric board through the trapezoidal matching branch.

[0032] Furthermore, the trapezoidal matching branch is located directly below the rectangular matching branch.

[0033] The following is a more specific embodiment:

[0034] Reference Figures 1 to 3 The present embodiment includes a low-profile broadband array antenna comprising a vibrator unit, a synthesis network, a metal floor and a periodic loading layer. The vibrator unit is a parallel double-line feeding inhomogeneous printed dipole, which is printed on both sides of a microwave dielectric plate. The synthesis network is a broadband parallel double-line synthesis feeding network based on exponential line impedance transformation.

[0035] The oscillator unit, synthesis network and matching conversion are integrated on the same microwave dielectric board. The periodic loading layer uses a square metal coating printed by microstrip, and the square size is less than 0.08 wavelength of the center frequency. The periodic loading layer is between the metal floor and the dielectric matching layer. The dielectric matching layer and periodic loading layer of the antenna are fixed on the metal floor through dielectric support 3.

[0036] This embodiment obtains a low-profile broadband flat antenna with excellent electrical performance by adding a metal microstructure loading method between the printed dipole and the metal reflective base plate. The voltage standing wave ratio is less than 2.0 within the 66.7% frequency bandwidth range, and the antenna height is 0.1 times the low-frequency wavelength.

[0037] In this embodiment, the metal patch on the upper surface of the first microwave dielectric plate of the dielectric matching layer is located on the left side of its corresponding feeding network, and the metal patch on the lower surface is located on the right side of its corresponding feeding network.

[0038] Brief working principle of the present invention:

[0039] The parallel two-wire fed out-of-plane printed dipole forms directional radiation through the reflection of electromagnetic waves by the metal floor. The balanced feeding of the printed dipole and ultra-wideband high impedance to low impedance matching are achieved through the parallel two-wire to microstrip structure. By adding metal microstructure loading between the printed dipole and the metal base plate, the phase distribution between the dipole and the metal floor is changed, and finally an ultra-wideband planar antenna unit with low profile characteristics and excellent electrical performance is obtained.

Claims

1. A low-profile broadband array antenna, comprising a coaxial feed interface, characterized in that: It also includes a dielectric matching layer, a periodic loading layer and a metal floor (3) stacked in sequence; an air layer is provided between the dielectric matching layer and the periodic loading layer and between the periodic loading layer and the metal floor; The dielectric matching layer comprises a first microwave dielectric substrate (1); a vibrator unit is provided on the first microwave dielectric substrate, the vibrator unit is a parallel double-line feeding off-plane printed dipole; the parallel double-line feeding off-plane printed dipole comprises a synthetic network, the synthetic network is a broadband parallel double-line synthetic feeding network based on exponential line impedance transformation; The periodic loading layer comprises a second microwave dielectric substrate (2), on which square metal coatings arranged in a rectangular array are provided; The inner conductor and the outer conductor of the coaxial feeding interface are respectively connected to the main path of the synthetic network on the upper surface and the main path of the synthetic network on the lower surface of the first microwave dielectric board; the broadband parallel two-wire synthetic feeding network based on exponential line impedance transformation is a one-to-eight feeding network (4); the parallel two-wire feeding off-plane printed dipole includes a metal patch (5); the projections of the feeding networks on the upper and lower surfaces of the first microwave dielectric board overlap; the branch ends of the feeding network are all connected to the metal patch, and the metal patch is located on one side of the branch end; the metal patches corresponding to the upper and lower surfaces of the first microwave dielectric board are respectively located on the opposite sides of the branch end; The side length of the square metal coating is less than 0.08 times the wavelength of the center frequency.

2. A low-profile broadband array antenna according to claim 1, characterized in that: The main circuit of the upper surface feeding network of the first microwave dielectric board is connected with a rectangular matching branch (6), and the inner conductor of the coaxial feeding interface is connected with the main circuit of the upper surface synthesis network of the first microwave dielectric board through the rectangular matching branch; the main circuit of the lower surface feeding network of the first microwave dielectric board is connected with a trapezoidal matching branch (7), and the outer conductor of the coaxial feeding interface is connected with the main circuit of the lower surface synthesis network of the first microwave dielectric board through the trapezoidal matching branch.

3. A low-profile broadband array antenna according to claim 2, characterized in that: The trapezoidal matching branch is located directly below the rectangular matching branch.

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