Broadband circularly polarized folded transmission array antenna based on tunable phase polarization conversion surface

Abstract

The present invention belongs to the technical field of transmission array antennas, and specifically relates to a broadband circularly polarized folded transmission array antenna based on an adjustable phase polarization conversion surface. The present invention includes an adjustable phase polarization converter and a circularly polarized twisted reflection surface arranged up and down; the adjustable phase polarization converter includes a plurality of adjustable phase polarization conversion surface units arranged periodically; the adjustable phase polarization conversion surface unit proposed in the present invention has a polarization selection characteristic, which can reflect the incident left-handed circularly polarized electromagnetic wave and twist the incident right-handed circularly polarized electromagnetic wave to transmit it into a left-handed circularly polarized electromagnetic wave, and can be applied to a folded transmission array to reduce the overall cross-section of the array. The broadband circularly polarized folded transmission array antenna based on an adjustable phase polarization conversion surface proposed in the present invention can reduce the cross-section by one third due to its polarization selection characteristic by introducing a polarization converter. The antenna of the present invention has a small number of layers, a simple structure, is easy to process, and has a low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of transmission array antennas, and in particular relates to a broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface. Background Art

[0002] With the rapid development of 6G mobile communications, radars, satellites and other wireless communication systems, high gain, broadband and low profile have become one of the development trends of modern millimeter wave antennas. Traditional antenna designs can only work within a specific frequency range, while broadband antennas can achieve good performance within a wider frequency range. At the same time, circularly polarized antennas can achieve polarization in the horizontal and vertical directions, and have better multipath propagation characteristics and anti-interference capabilities than linearly polarized antennas. In wireless communication systems, circular polarization technology can improve signal transmission quality and coverage, and reduce signal attenuation and multipath effects.

[0003] Broadband circularly polarized folded transmission array antenna is an antenna technology used in wireless communication systems, especially in 5G and future communication systems, it has broad application prospects. Traditional circularly polarized transmission array antennas often achieve circular polarization conversion and broadband performance through an air layer, which makes the antenna structure complex. In order to accurately control the thickness of the air layer, the processing and assembly requirements are high. In addition, the introduction of the air layer makes the structure have more layers and a higher profile, which is difficult to integrate with other planar circuits.

[0004] Haoyu Lei et al. proposed a circularly polarized folded transmission array antenna based on a circularly polarized feed source. By adding metal through holes to transmit circularly polarized electromagnetic waves, the air layer is removed, and a circularly polarized transmission antenna is realized with three layers of metal and two layers of dielectrics. Then, a layer of circularly polarized twisted surface is added to realize a folded array antenna, which greatly reduces the antenna profile. However, due to the narrowband characteristics of the transmission array unit, the bandwidth of the circularly polarized transmission array finally realized is also narrow. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface, which can achieve a wider bandwidth at a lower profile. The antenna adopts circularly polarized feeding and transmits circularly polarized electromagnetic waves through metal through holes, which can achieve polarization conversion, torsion and selection performance.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0007] A broadband circularly polarized folded transmission array antenna based on an adjustable phase polarization conversion surface comprises an adjustable phase polarization converter and a circularly polarized twisted reflection surface arranged up and down; the adjustable phase polarization converter comprises a plurality of periodically arranged adjustable phase polarization conversion surface units; the adjustable phase polarization conversion surface unit comprises an upper metal patch layer, an upper dielectric substrate layer, an intermediate metal stratum, an adhesive layer, a lower dielectric substrate layer and a lower metal patch layer which are sequentially stacked from top to bottom; a metal through hole is located in the middle of the adjustable phase polarization conversion surface unit The core is used to connect the upper metal patch layer and the lower metal patch layer; the upper metal patch layer is circular and etched with an open square ring and a diagonal rectangular gap; the middle metal stratum is etched with a circular gap; the lower metal patch layer is circular and etched with an open square ring and a diagonal rectangular gap; the circularly polarized twisted reflection surface includes a metal patch layer and a dielectric substrate layer stacked in sequence from top to bottom; the metal patch layer includes a whole square metal patch; the center of the circularly polarized twisted reflection surface is hollowed out to set a circularly polarized feed horn.

[0008] Further, as a preferred technical solution of the present invention, the feed horn outputs circularly polarized electromagnetic waves, which are incident on the lower surface of the phase-adjustable polarization converter and reflected onto the circularly polarized twisted reflection surface.

[0009] Further, as a preferred technical solution of the present invention, the circularly polarized twisted reflection surface receives circularly polarized electromagnetic waves through a metal patch layer, and the twisted circularly polarized electromagnetic waves are reflected to the lower metal patch layer of several adjustable phase polarization conversion surface units of the adjustable phase polarization converter, and are transmitted to the upper metal patch layer through metal through holes.

[0010] Further, as a preferred technical solution of the present invention, the structures of the upper metal patch layer and the lower metal patch layer may be different and the 45° offset distance s about the metal through hole in the x and y positive semi-axis directions may also be different.

[0011] Further, as a preferred technical solution of the present invention, the upper metal patch layer and the lower metal patch layer can also be set as rectangular metal patches.

[0012] Further, as a preferred technical solution of the present invention, the square opening rings of the upper metal patch layer and the lower metal patch layer can also be set as circular opening rings.

[0013] Further, as a preferred technical solution of the present invention, the upper metal patch layer and the lower metal patch layer can be offset by the same distance s at 45° in the x and y negative semi-axis directions with respect to the metal through-holes.

[0014] Further, as a preferred technical solution of the present invention, the upper metal patch layer and the lower metal patch layer can be rotated clockwise and counterclockwise by any one of 90°, 180°, and 270° with respect to the metal through hole.

[0015] Further, as a preferred technical solution of the present invention, the openings of the upper metal patch layer and the lower metal patch layer can also be in any direction of the negative half axis of the y-axis, the positive half axis of the x-axis and the negative half axis of the x-axis of the square ring.

[0016] The broadband circularly polarized folded transmission array antenna based on the adjustable phase polarization conversion surface of the present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0017] (1) The phase-adjustable polarization conversion surface unit proposed in the present invention has a polarization selection characteristic, which can reflect the incident left-hand circularly polarized electromagnetic wave and twist the incident right-hand circularly polarized electromagnetic wave to transmit it into a left-hand circularly polarized electromagnetic wave. It can be applied to a folded reflective array to reduce the overall profile of the array.

[0018] (2) The phase-adjustable polarization conversion surface unit proposed in the present invention can achieve 360° phase adjustment by rotating the upper metal patch layer, and can achieve linear phase in a wider frequency band.

[0019] (3) The broadband circularly polarized folded transmission array antenna based on the phase-adjustable polarization conversion surface proposed in the present invention can reduce its cross-section by one third by introducing a polarization converter due to its polarization selection characteristics.

[0020] (4) The broadband circularly polarized folded transmission array antenna based on the phase-adjustable polarization conversion surface proposed in the present invention has a small number of layers, a simple structure, is easy to process, and has a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the three-dimensional structure of an antenna according to an embodiment of the present invention;

[0022] Figure 2 is a side view of an antenna according to an embodiment of the present invention;

[0023] Figure 3 is a top view of the adjustable phase polarization conversion surface of the antenna according to an embodiment of the present invention;

[0024] Figure 4 is a top view of the circularly polarized twisted reflection surface of the antenna according to an embodiment of the present invention;

[0025] Figure 5 is a schematic diagram of the three-dimensional structure of the adjustable phase polarization conversion surface unit of the antenna according to an embodiment of the present invention;

[0026] Figure 6Schematic diagram of the three-dimensional structure of the circularly polarized twisted reflection surface of the antenna according to the embodiment of the present invention;

[0027] Figure 7 is a top view of the upper metal patch layer of the antenna according to an embodiment of the present invention;

[0028] Figure 8 is a top view of the middle metal patch layer of the antenna according to an embodiment of the present invention;

[0029] Fig. 9 is a top view of the lower metal patch layer of the antenna according to an embodiment of the present invention;

[0030] Fig.10 is the t of the adjustable phase polarization conversion surface unit of the antenna of the embodiment of the present invention xx ,t yy Transmission coefficient and phase response performance diagram;

[0031] Fig.11 is the phase-adjustable polarization conversion surface unit of the antenna of the embodiment of the present invention. xx 、r yy Reflection coefficient and phase response performance graphs;

[0032] Fig.12 is the t of the adjustable phase polarization conversion surface unit of the antenna of the embodiment of the present invention xy ,t yx Transmission coefficient and phase response performance diagram;

[0033] Fig.13 is the phase-adjustable polarization conversion surface unit of the antenna of the embodiment of the present invention. xy 、r yx Reflection coefficient and phase response performance graphs;

[0034] Fig.14 is a transmission and reflection response diagram of a left-hand circularly polarized wave of a phase-adjustable polarization conversion surface unit of an antenna according to an embodiment of the present invention;

[0035] Fig.15 is a transmission and reflection response diagram of a right-hand circularly polarized wave of a phase-adjustable polarization conversion surface unit of an antenna according to an embodiment of the present invention;

[0036] Fig.16 are the E-plane and H-plane radiation patterns of the antenna of the present invention at the center frequency;

[0037] Fig.17 are the main polarization pattern and axial ratio pattern of the antenna of the present invention at the center frequency;

[0038] Fig.18 is a performance diagram of the gain and axial ratio of the antenna of the present invention varying with frequency;

[0039] In the accompanying drawings, 1-adjustable phase polarization conversion surface unit; 2-circular polarization twisted reflection surface; 3-upper metal patch layer; 4-upper dielectric substrate layer; 5-middle metal stratum; 6-adhesive layer; 7-lower dielectric substrate layer; 8-lower metal patch layer; 9-metal through hole; 10-metal patch layer; 11-dielectric substrate layer. DETAILED DESCRIPTION

[0040] The present invention is further explained below in detail with reference to the accompanying drawings so that those skilled in the art can more deeply understand the present invention and be able to implement it. However, the following reference examples are only used to explain the present invention and are not intended to limit the present invention.

[0041] like Figure 1-9 As shown, a broadband circularly polarized folded transmission array antenna based on an adjustable phase polarization conversion surface includes an adjustable phase polarization converter and a circularly polarized twisted reflection surface 2 arranged up and down; the adjustable phase polarization converter includes a plurality of adjustable phase polarization conversion surface units 1 arranged periodically; the adjustable phase polarization conversion surface unit 1 includes an upper metal patch layer 3, an upper dielectric substrate layer 4, an intermediate metal layer 5, an adhesive layer 6, a lower dielectric substrate layer 7 and a lower metal patch layer 8 stacked in sequence from top to bottom; a metal through hole 9 is located on the adjustable phase polarization conversion surface The center of unit 1 is used to connect the upper metal patch layer 3 and the lower metal patch layer 8; the upper metal patch layer 3 is circular and etched with an open square ring and a diagonal rectangular gap; the middle metal layer 5 is etched with a circular gap; the lower metal patch layer 8 is circular and etched with an open square ring and a diagonal rectangular gap; the circularly polarized twisted reflection surface 2 includes a metal patch layer 10 and a dielectric substrate layer 11 stacked in sequence from top to bottom; the metal patch layer 10 includes a whole square metal patch; the center of the circularly polarized twisted reflection surface 2 is hollowed out to set a circularly polarized feed horn.

[0042] like Figure 2 As shown, the feed horn outputs a left-handed circularly polarized electromagnetic wave, which is incident on the lower surface of the adjustable phase polarization converter. Due to the polarization selection characteristics of the adjustable phase polarization converter, the left-handed circularly polarized electromagnetic wave cannot penetrate the structure, but is reflected on the circularly polarized twisted reflection surface 2. The circularly polarized twisted reflection surface 2 twists the left-handed circularly polarized electromagnetic wave into a right-handed circularly polarized electromagnetic wave, and it is incident on the lower surface of the adjustable phase polarization converter again. Due to the polarization selection characteristics of the adjustable phase polarization converter, the right-handed circularly polarized electromagnetic wave is received by the lower metal patch layer 8, transmitted to the upper metal patch layer 3 through the metal through hole 9, twisted into a left-handed circularly polarized electromagnetic wave, and corresponding phase compensation is obtained.

[0043] The parameters of the antenna in this embodiment are shown in the following table:

[0044] parameter p <![CDATA[r1]]> <![CDATA[h1]]> <![CDATA[h2]]> <![CDATA[d1]]> <![CDATA[d2]]> Value(mm) 5.3 1.7 0.787 0.1 0.3 0.6 parameter <![CDATA[a1]]> <![CDATA[a2]]> <![CDATA[a3]]> s <![CDATA[w1]]> <![CDATA[l1]]> Value(mm) 1.7 1.2 0.7 0.43 0.3 0.55

[0045] p is the side length of the dielectric substrate, r1 is the radius of the circular metal patch, h1 is the height of the dielectric substrate, h2 is the height of the adhesive layer, d1 is the diameter of the metal through hole, d2 is the diameter of the circular gap of the floor layer, a1 is the outer side length of the open square ring, a2 is the inner side length of the open square ring, a3 is the opening length of the open square ring, s is the distance that the metal patch is offset in the xoy direction relative to the metal through hole, w1 is the width of the diagonally extended gap of the open square ring, and l1 is the length of the diagonally extended gap of the open square ring.

[0046] like Figure 5 As shown, the upper dielectric substrate layer 4 and the lower dielectric substrate layer 7 of the adjustable phase polarization conversion surface unit 1 are made of the same material and size, and their dielectric constant εr is [2.2, 6.2], tanδ is 0.0009, and the height h1 is [0.02λ, 0.1λ]. The dielectric constant εr of the bonding layer 6 is 3.5, tanδ is 0.004, and the height is h2. The metal through hole 9 is made of pec. In addition, the dielectric constant εr of the circularly polarized twisted reflection surface 2 is [2.2, 6.2], tanδ is 0.0009, and the height h1 is [0.02λ, 0.1λ], where λ is the free space wavelength.

[0047] like Figure 7 As shown, the xoy surface of the adjustable phase polarization conversion surface unit 1 is a square structure, its side length p is [0.2λ, λ], the radius r1 of the circular metal patch on its surface is [0.1λ, 0.5λ], an open square ring is etched on the metal patch, the outer side length a1 of the open square ring is [0.1λ, 0.5λ], the inner side length a2 is [0.1λ, 0.5λ], the opening length a3 is [0.01λ, 0.1λ], a gap extends diagonally from the square ring, the width w1 of the gap is [0.01λ, 0.1λ], and the length l1 is [0.01λ, 0.1λ]. And the circular metal patch is offset by a distance s of [0.01λ, 0.1λ] in the xoy direction relative to the metal through hole. As shown Fig. 9 As shown, the lower metal patch layer 8 has the same structure as the upper metal patch layer 3 .

[0048] like Figure 8 As shown, the middle metal layer 5 of the adjustable phase polarization conversion surface unit 1 is a square structure with a side length of p. A metal through hole 9 with a diameter d1 [0.03λ, 0.06λ] passes through the center of its surface, and a circular gap with a diameter d2 of [0.06λ, 0.1λ] is etched in the center, so that the metal through hole 9 can pass through and connect the upper and lower metal patches.

[0049] like Fig.10 As shown, the coefficient and phase change of the adjustable phase polarization conversion surface unit 1 in the frequency range are, xx and t yyAt the center frequency of 28 GHz, the amplitudes are equal to -6 dB, and t xx -t yy =180°; Fig.11 As shown, t xy and t yx At the center frequency of 28GHz, the amplitudes are equal to -6dB and the phases are equal. Fig.12 As shown, r xx and r yy At the center frequency of 28 GHz, the amplitudes are equal to -6 dB, and r xx -r yy =180°; Fig.13 As shown, r xy and r yx At the center frequency of 28GHz, the amplitudes are equal to -6dB and the phases are equal.

[0050] like Fig.14 As shown, the phase-adjustable polarization conversion surface unit 1 can reflect left-hand circular polarization within the frequency range without changing the polarization characteristics; Fig.15 As shown, the phase-adjustable polarization conversion surface unit 1 can transmit right-hand circular polarization within the frequency range, and twist the polarization into left-hand circular polarization.

[0051] like Figure 16-17 As shown, the main polarization of the circularly polarized folded transmission array antenna is about 25 dB at the center frequency of 28 GHz. In addition, when theta = 0°, its cross-polarization level is less than -10 dB, and the axis ratio is good.

[0052] like Fig.18 As shown, in the frequency range of 24-30 GHz, the antenna has a 3 dB gain bandwidth of 12.7% and an axial ratio bandwidth of 11.3%.

[0053] The specific implementation scheme described above further describes in detail the purpose, technical scheme and beneficial effects of the present invention. It should be understood that the above is only a specific implementation scheme of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any technician in the field without departing from the concept and principle of the present invention should fall within the scope of protection of the present invention.

Claims

1. A broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface, characterized in that: The invention comprises an adjustable phase polarization converter and a circular polarization twisted reflection surface (2) arranged in an upper and lower manner; the adjustable phase polarization converter comprises a plurality of adjustable phase polarization conversion surface units (1) arranged in a periodic manner; the adjustable phase polarization conversion surface unit (1) comprises an upper metal patch layer (3), an upper dielectric substrate layer (4), an intermediate metal layer (5), an adhesive layer (6), a lower dielectric substrate layer (7) and a lower metal patch layer (8) which are stacked in sequence from top to bottom; a metal through hole (9) is located in the center of the adjustable phase polarization conversion surface unit (1) and is used to connect the upper metal patch layer to the intermediate metal layer (5); a metal through hole (9) is provided ... The circular polarization twisted reflection surface (2) comprises a metal patch layer (10) and a dielectric substrate layer (11) which are stacked in sequence from top to bottom; the metal patch layer comprises a whole square metal patch; the circular polarization feed horn is arranged in the center of the hollowed-out circular polarization twisted reflection surface (2); The circularly polarized feed horn outputs a circularly polarized electromagnetic wave, which is incident on the lower surface of the phase-adjustable polarization converter and reflected onto the circularly polarized twisted reflection surface (2); The circularly polarized twisted reflection surface (2) receives circularly polarized electromagnetic waves through a metal patch layer (10), and the twisted circularly polarized electromagnetic waves are reflected onto a lower metal patch layer (8) of a plurality of adjustable phase polarization conversion surface units (1) of an adjustable phase polarization converter, and are transmitted to an upper metal patch layer (3) through a metal through hole (9).

2. The broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface according to claim 1, characterized in that: The upper metal patch layer (3) and the lower metal patch layer (8) have different structures and are also different in 45° offset distance s in the x and y positive semi-axis directions with respect to the metal through hole (9).

3. The broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface according to claim 1, characterized in that: The upper metal patch layer (3) and the lower metal patch layer (8) are offset by the same distance s at 45° in the x and y negative semi-axis directions with respect to the metal through hole (9).

4. The broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface according to claim 1, characterized in that: The upper metal patch layer (3) and the lower metal patch layer (8) are rotated clockwise and counterclockwise by any one of 90°, 180°, and 270° with respect to the metal through hole (9).

5. The broadband circularly polarized folded transmission array antenna based on a phase-adjustable polarization conversion surface according to claim 1, characterized in that: The openings of the upper metal patch layer (3) and the lower metal patch layer (8) are in any direction of the negative half axis of the y axis, the positive half axis of the x axis, and the negative half axis of the x axis of the square ring.

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