Broadband dual-polarization indoor antenna with symmetrically broadened wave beams

Abstract

The invention discloses a broadband dual-polarization indoor antenna with symmetrically broadened wave beams. An orthogonal embedded balun is located between an orthogonal dual-polarization printed dipole and a square metal ground; a bottom end plug pin of each balun is used as a signal feed port, and a top end plug pin of each balun is correspondingly inserted into the rectangular through holes of the pair of dipoles respectively; the four cross-shaped edgefold metal strips are respectively supported above the orthogonal dual-polarization printed dipoles by the support columns and are respectively arranged end to end along the polarization direction of the two orthogonal dipoles; and the four trapezoidal right-angle bent plates are distributed at four opposite angles of the orthogonal dual-polarization printed dipole, and the bottoms of the trapezoidal right-angle bent plates are connected with the square metal ground. According to the invention, the symmetrically distributed cross-shaped edgefold metal strips and the trapezoidal right-angle bent plates act on the orthogonal dual-polarization printed dipoles, and the two plates are used for broadening symmetrical wave beams of high-frequency and low-frequency E-planes and H-planes and expanding impedance matching bandwidth. And relatively wide double-sided symmetric beam broadening bandwidth and impedance matching bandwidth are realized.

Description

Technical Field

[0001] The invention relates to a microwave communication device, in particular to a broadband dual-polarization indoor antenna. Background Art

[0002] An indoor antenna is a device used to receive and transmit wireless signals in an indoor environment. Its main functions include enhancing signal strength, increasing transmission rate and reducing interference. Wide-beam indoor antennas can expand their coverage area, effectively reduce signal blind spots, and ensure continuous coverage in multiple rooms or complex layouts. E noodle, H A wide beam antenna with symmetrical widening can provide more uniform coverage in indoor environments. At the same time, in complex indoor or high-density scenarios, broadband dual-polarization is also required to increase channel capacity, adapt to multi-band and high-density device requirements, support more devices to connect concurrently, and reduce network congestion. Therefore, the beam width of broadband dual-polarization indoor antennas needs to take into account E noodle, H The wide beam bandwidth and matching bandwidth as well as the symmetry of the beam widths of the two polarizations form a broadband dual-polarization indoor antenna with symmetrical beam broadening. Such antennas have important engineering value and significance for indoor communications.

[0003] There are four main methods for widening the beam width of dual-polarized antennas: The first method is to tilt the metal ground of the dual-polarized dipole downward to widen the beam width, but it can only widen H The second method uses a low-profile dual-polarized magneto-electric dipole and a small-sized metal ground with metalized blind holes at the four corners to achieve beam broadening, but this beam broadening method can only achieve H Wide beam radiation on the surface, E The surface beam width is narrow, and the matching bandwidth and beam broadening bandwidth show dual-band characteristics, and the bandwidth is still narrow; the third is a dual-polarization square patch antenna fed by a differential probe, which can achieve double-sided beam broadening through the reverse co-polarization current on the four perforated T-shaped strips extending outward from the patch, and the reverse polarization electric field brought by a pair of back-to-back U-shaped strips on the outside of each T-shaped strip, but the symmetry of the double-sided beam broadening is poor, and the overall planar size is large, and the matching bandwidth and beam broadening bandwidth are both narrow; the fourth is a square dual-polarization patch antenna fed by slot coupling, which adds grounded L-shaped metal strips on the outside of the four corners of the upper layer to synchronously broaden the E Face to face H In summary, the above methods cannot achieve a wider beam broadening bandwidth, and some designs cannot achieve double-sided beam broadening and the symmetry of double-sided beam broadening. Therefore, it is necessary to propose a broadband dual-polarization indoor antenna with symmetrical beam broadening. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a broadband dual-polarization indoor antenna is proposed to achieve dual-sided beam broadening, and take into account the matching and beam broadening bandwidth, and the symmetry of the dual-sided beam broadening.

[0005] Technical solution: A broadband dual-polarization indoor antenna with symmetrical beam broadening, comprising four cross-shaped folded metal strips, an orthogonal dual-polarization printed dipole, an orthogonal embedded balun, four trapezoidal right-angle bent plates, a square metal ground and a plurality of pillars; the orthogonal dual-polarization printed dipole comprises a dielectric substrate, and four orthogonal metal strips with rectangular through holes on the surface of the dielectric substrate; the orthogonal embedded balun is composed of two vertically arranged baluns orthogonally embedded, and the orthogonal embedded balun is located between the orthogonal dual-polarization printed dipole and the square metal ground; the bottom pins of each balun are used as signal feed The electrical ports vertically pass through the rectangular slots on the square metal ground respectively; the top pins of each balun are respectively inserted into the rectangular through holes of a pair of dipoles; four cross-shaped folded metal strips are respectively supported by pillars above the orthogonal dual-polarization printed dipoles, and are divided into a group of two, and are arranged end to end along the polarization direction of the two orthogonal dipoles; four trapezoidal right-angle bent plates are distributed at the four diagonals of the orthogonal dual-polarization printed dipoles, and the bottom is connected to the square metal ground, and the two bent surfaces of each trapezoidal right-angle bent plate are respectively parallel to the two orthogonal surfaces of the orthogonal mosaic balun.

[0006] Furthermore, each cross-shaped folded metal strip consists of two equal-length short horizontal strips, one long horizontal strip and one vertical strip. The short horizontal strips and the long horizontal strips are both located in the horizontal plane, and part of the length of the long horizontal strip overlaps with the metal strip of the dipole in the vertical plane. The vertical strip located on the outside is perpendicular to the horizontal plane.

[0007] Furthermore, the trapezoidal right-angle bent plate is formed by bending an isosceles trapezoidal metal sheet at 90 degrees along its own symmetry axis.

[0008] Furthermore, the length of the horizontal short strip is 0.14λ 0 -0.16λ 0 The length of the horizontal strip is between 0.19λ 0 -0.21λ 0 The length of the overlapping part of the horizontal strip and the dipole is 0.08λ 0 -0.12λ 0 The length of the vertical strip is between 0.18λ 0 -0.20λ 0 Between 0 is the free space wavelength corresponding to the center frequency.

[0009] Furthermore, the total length of the upper base of the trapezoidal right-angle bent plate is 0.09λ 0 -0.13λ 0 The total length of the bottom is 0.26λ 0 -0.30λ 0 Between, up to 0.20λ 0 -0.24λ 0 The spacing between the parallel bending surfaces of two adjacent trapezoidal right-angle bending plates is 0.18λ 0 -0.22λ 0 between.

[0010] Beneficial effects: The existing dual-polarization indoor antenna cannot achieve a wider beam broadening bandwidth, and has one or more of the following problems: the dual-side beam broadening cannot be achieved, the dual-side beam broadening symmetry is poor, etc. The present invention uses symmetrically distributed cross-shaped folded metal strips and trapezoidal right-angle bent plates to act on orthogonal dual-polarization printed dipoles, and uses the two to respectively control high-frequency and low-frequency E noodle, H The symmetrical beam broadening effect and the expansion effect on the impedance matching bandwidth realize a wider double-sided symmetrical beam broadening bandwidth and impedance matching bandwidth.

[0011] Specifically, four cross-shaped folded metal strips are supported by pillars above the orthogonal dual-polarization printed dipoles and are divided into two groups and arranged end to end along the polarization direction of the corresponding dipoles. Each cross-shaped folded metal strip consists of two equal-length horizontal short strips, a horizontal long strip and a vertical strip in the horizontal plane. Based on the current distribution characteristics of the strips and the setting of the strip length, it mainly acts on high frequencies. On the one hand, it can expand the impedance matching bandwidth. On the other hand, a pair of cross-shaped folded metal strips in the polarization direction are E The beam broadening effect of the plane is achieved by a pair of cross-shaped folded metal strips perpendicular to the polarization direction. H The beam broadening of the surface has an effect, and E noodle H The beam broadening degree of the surface is comparable.

[0012] Four trapezoidal right-angle bending plates are bent 90 degrees along their own symmetry axis, and their bottoms are connected to the square metal ground, located at the four diagonals of the orthogonal dual-polarization printed dipoles. Its current distribution characteristics constitute two in-phase equivalent magnetic dipoles perpendicular to the polarization direction in any polarization operation, which can widen the low-frequency band. E Surface and H The surface beam width and the provision of low-frequency resonance points extend the impedance matching bandwidth. E noodle H The beam broadening degree of the surface is comparable. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1Schematic diagram of the three-dimensional structure of the antenna of the present invention; Figure 2 Schematic diagram of the projection structure of the antenna of the present invention on the XOZ plane; Figure 3 It is a schematic diagram of the structure of an orthogonal dual-polarized printed dipole in the antenna of the present invention; Figure 4 It is a schematic diagram of the structure of the balun in the antenna of the present invention; Figure 5 For the embodiment of the present invention S Parameter simulation results; Figure 6 is the beam width simulation result of the embodiment of the present invention; Figure 7 For the embodiment of the present invention E noodle, H Surface simulation radiation pattern; (a) corresponds to 3.7 GHz, (b) corresponds to 4.2 GHz, and (c) corresponds to 5 GHz. DETAILED DESCRIPTION

[0014] The present invention will be further explained below in conjunction with the accompanying drawings.

[0015] like Figure 1 , Figure 2 As shown, a broadband dual-polarization indoor antenna with symmetrical beam broadening is mainly composed of four cross-shaped folded edge metal strips 1, an orthogonal dual-polarization printed dipole 2, an orthogonal embedded balun 3, four trapezoidal right-angle bent plates 4, a square metal ground 5 and four pillars 6.

[0016] The orthogonal dual-polarization printed dipole 2 is composed of a dielectric substrate and four orthogonal metal strips with rectangular through holes on its surface. The rectangular through holes are located at the feeding ends of each metal strip close to each other, such as Figure 3 shown.

[0017] The orthogonal interlocking balun 3 is composed of two vertically arranged baluns interlocked orthogonally. Figure 4As shown, the structure of a single balun consists of a vertical dielectric substrate 303, a bent metal strip 304, and two stepped metal strips 302. As a part of the vertical dielectric substrate 303, two narrow pins 301 are symmetrically formed at the top of the vertical dielectric substrate 303, and two wide pins 305 are symmetrically formed at the bottom. The bent metal strip 304 is located on the front side of the vertical dielectric substrate 303, and the bent metal strip 304 is composed of a vertical part and a bent part connected to the top of the vertical part. The two stepped metal strips 302 are symmetrically distributed on the back side of the vertical dielectric substrate 303, and cover the narrow pin 301 at the top and the wide pin 305 at the bottom, respectively. The area of ​​one of the stepped metal strips 302 covers the vertical part of the bent metal strip 304, and the bottom end of the vertical part of the bent metal strip 304 is flush with the bottom end of the wide pin 305. A vertical slot is provided in the center of the vertical dielectric substrate 303 of the two baluns, wherein the slot of one balun extends from the lower side of the top horizontal section of the bent metal strip 304 to the bottom end of the substrate, and the slot of the other balun extends from the upper side of the top horizontal section of the bent metal strip 304 to the top end of the substrate, and the two baluns are connected to each other through the slot.

[0018] The orthogonal chimeric balun 3 is located between the orthogonal dual-polarization printed dipole 2 and the square metal ground 5. The square metal ground 5 has four rectangular slots, and the four wide pins 305 at the bottom of the orthogonal chimeric balun 3 pass through the rectangular slots one by one, and the bottom ends thereof serve as signal feeding ports; the four narrow pins 301 at the top of the orthogonal chimeric balun 3 are inserted into the rectangular through holes of the orthogonal dual-polarization printed dipole 2 one by one.

[0019] Four cross-shaped folded metal strips 1 are supported by pillars 6 above the orthogonal dual-polarization printed dipoles 2. The four cross-shaped folded metal strips 1 are divided into two groups, and the two groups are arranged end to end along the polarization directions of the two orthogonal dipoles. Specifically, each cross-shaped folded metal strip 1 is composed of two equal-length horizontal short strips 1-1, a horizontal long strip 1-2 and a vertical strip 1-3. The horizontal short strip 1-1 and the horizontal long strip 1-2 are both located in the horizontal plane ( XOY Surface), and part of the length of the horizontal strip 1-2 is in the vertical surface ( XOZ The vertical strips 1-3 on the outside are perpendicular to the horizontal plane.

[0020] Among them, the length of the horizontal short strip 1-1 is 0.14λ 0 -0.16λ 0 The length of the horizontal strip 1-2 is 0.19λ 0 -0.21λ 0 The length of the overlapping part of the horizontal strip 1-2 and the dipole is 0.08λ 0 -0.12λ 0The length of vertical strips 1-3 is between 0.18λ 0 -0.20λ 0 Between 0 is the free space wavelength corresponding to the center frequency.

[0021] The trapezoidal right-angle bending plate 4 is formed by bending an isosceles trapezoidal metal sheet at 90 degrees along its own symmetry axis. Four trapezoidal right-angle bending plates 4 are symmetrically distributed at four diagonals of the orthogonal dual-polarization printed dipole 2, and their bottoms are connected to the square metal ground 5. The two bending surfaces of each trapezoidal right-angle bending plate 4 are parallel to the two orthogonal surfaces of the orthogonal mosaic balun 3.

[0022] Among them, the total length of the upper base of the trapezoidal right-angle bent plate 4 is 0.09λ 0 -0.13λ 0 The total length of the bottom is 0.26λ 0 -0.30λ 0 Between, up to 0.20λ 0 -0.24λ 0 The spacing between the parallel bending surfaces of two adjacent trapezoidal right-angle bending plates 4 is 0.18λ 0 -0.22λ 0 between.

[0023] For the proposed broadband dual-polarization indoor antenna with symmetrical beam broadening, the signal is fed through the orthogonal embedded balun 3 and coupled to the corresponding polarized dipoles in the orthogonal dual-polarization printed dipole 2. Under the combined action of the trapezoidal right-angle bending plate 4, the cross-shaped folded metal strip 1 and the square metal ground 5, broadband dual-polarization radiation with a symmetrical wide beam is formed.

[0024] In this process, the orthogonal dual-polarization printed dipole 2 realizes the basic dual-polarization radiation function. When any polarization in the dual polarization is working, the current of a pair of cross-shaped folded metal strips 1 arranged along the polarization direction is mainly distributed on the horizontal long strips 1-2 and the vertical strips 1-3, and the currents on the two horizontal long strips 1-2 in the pair of structures are in phase, and the currents on the two vertical strips 1-3 are in anti-phase; the current on the horizontal long strips 1-2 of the same cross-shaped folded metal strip 1 is continuous with the current on the vertical strips 1-3. The current of a pair of cross-shaped folded metal strips 1 arranged along the vertical polarization direction is mainly distributed on the horizontal short strips 1-1, and the currents on the two horizontal short strips 1-1 of the same cross-shaped folded metal strip 1 are continuous, and the currents on the pair of cross-shaped folded metal strips 1 are in phase. The current on the horizontal strip of the above-mentioned cross-shaped folded metal strip 1 is opposite to the dipole current of the corresponding polarization. Based on the above current distribution characteristics and strip length setting, the cross-shaped folded metal strip 1 mainly works at high frequencies. On the one hand, it can expand the impedance matching bandwidth. On the other hand, a pair of cross-shaped folded metal strips 1 in the polarization direction areE The beam broadening of the surface has an effect, and a pair of cross-shaped folded metal strips perpendicular to the polarization direction are 1 pair H The beam broadening of the surface has an effect, and E noodle H The beam broadening degree of the surface is comparable.

[0025] Each trapezoidal right-angle bending plate 4 has two bending surfaces, which are used to ensure good coupling with the corresponding dipole in any polarization state during dual polarization operation. When working in any polarization, the current coupled to the trapezoidal right-angle bending plate 4 is mainly distributed on the bending surface perpendicular to the polarization direction, and the currents of the two bending surfaces arranged along the polarization direction are in anti-phase, and the currents of the two bending surfaces arranged along the polarization direction are in phase, thereby forming two equivalent magnetic dipoles in the same phase perpendicular to the polarization direction. Based on the setting of the equivalent magnetic dipole and the height of the trapezoidal right-angle bending plate 4, the trapezoidal right-angle bending plate 4 mainly works at low frequency. On the one hand, it can provide a low-frequency resonance point to expand the impedance matching bandwidth, and on the other hand, it can widen the low-frequency band. E Surface and H Surface beam width.

[0026] In summary, the low-frequency and high-frequency bands at any polarization E Face to face H The surface beam width is widened to a similar extent, and the matching bandwidth of the dual polarization is widened, so a broadband dual polarization indoor antenna with symmetrical beam widening can be realized.

[0027] The dielectric substrate used in this embodiment is RO4003C, the dielectric constant is 3.55, and the overall antenna unit size is 1.06λ 0 × 1.06 λ 0 × 0.37 λ 0 The simulation results of the matching response of this embodiment are as follows: Figure 5 As shown in the figure, the operating frequency band covers 3.27 GHz~5.27 GHz, and the relative bandwidth is 46.8%. E noodle, H The beam width is Figure 6 As shown, E The wide beam frequency range with a beam width of more than 110° is 3.67 GHz~5.37 GHz. H The frequency range of wide beam with a beam width above 110° is 3.67 GHz~5.5 GHz, and the relative bandwidth of the overlapping part between the dual-sided wide beam bandwidth and the working frequency band is 35.8%, that is, 3.67 GHz~5.27 GHz. Figure 7 When the antenna is working, the E Surface and H Surface simulation pattern, EThe half-power beamwidths are 113.6°, 142.2°, and 148° respectively. H The half-power beam widths are 116°, 128.6°, and 125.3°, respectively, and the cross-polarization levels are all below -17 dB. Compared with the best prior art, the present invention can achieve a wider dual-sided beam broadening bandwidth, and the dual-sided beam broadening has better symmetry.

[0028] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A broadband dual-polarization indoor antenna with symmetrical beam broadening, characterized in that: It includes four cross-shaped folded metal strips (1), an orthogonal dual-polarization printed dipole (2), an orthogonal chimeric balun (3), four trapezoidal right-angle bent plates (4), a square metal ground (5) and a plurality of pillars (6); The orthogonal dual-polarization printed dipole (2) comprises a dielectric substrate and four orthogonal metal strips with rectangular through holes on the surface of the dielectric substrate; The orthogonal embedded balun (3) is composed of two vertically arranged baluns orthogonally embedded in each other. The orthogonal embedded balun (3) is located between the orthogonal dual-polarization printed dipole (2) and the square metal ground (5); the bottom end pins of each balun serve as signal feeding ports and vertically pass through the rectangular slots on the square metal ground (5); the top end pins of each balun are respectively inserted into the rectangular through holes of a pair of dipoles; Four cross-shaped folded metal strips (1) are supported by pillars (6) above the orthogonal dual-polarization printed dipoles (2), and are grouped in pairs and arranged end-to-end along the polarization directions of the two orthogonal dipoles; Four trapezoidal right-angle bending plates (4) are distributed at four diagonal positions of the orthogonal dual-polarization printed dipole (2), and the bottom is connected to a square metal ground (5). The two bending surfaces of each trapezoidal right-angle bending plate (4) are respectively parallel to the two orthogonal surfaces of the orthogonal embedded balun (3).

2. The broadband dual-polarization indoor antenna according to claim 1, characterized in that: Each cross-shaped folded metal strip (1) is composed of two equal-length short horizontal strips (1-1), one long horizontal strip (1-2) and one vertical strip (1-3); the short horizontal strip (1-1) and the long horizontal strip (1-2) are both located in a horizontal plane, and part of the length of the long horizontal strip (1-2) overlaps with the metal strip of the dipole in the vertical plane; the vertical strip (1-3) located on the outside is perpendicular to the horizontal plane.

3. The broadband dual-polarization indoor antenna according to claim 1, characterized in that: The trapezoidal right-angle bent plate (4) is formed by bending an isosceles trapezoidal metal sheet at 90 degrees along its own symmetry axis.

4. The broadband dual-polarization indoor antenna according to claim 2 or 3, characterized in that: The length of the horizontal short strip (1-1) is between 0.14λ0-0.16λ0, the length of the horizontal long strip (1-2) is between 0.19λ0-0.21λ0, the length of the overlapping part of the horizontal long strip (1-2) and the dipole is between 0.08λ0-0.12λ0, and the length of the vertical strip (1-3) is between 0.18λ0-0.20λ0, where λ0 is the free space wavelength corresponding to the center frequency.

5. The broadband dual-polarization indoor antenna according to claim 4, characterized in that: The total length of the upper base of the trapezoidal right-angle bent plate (4) is between 0.09λ0-0.13λ0, the total length of the lower base is between 0.26λ0-0.30λ0, and the height is between 0.20λ0-0.24λ0; the spacing between the opposite parallel bending surfaces of two adjacent trapezoidal right-angle bent plates (4) is between 0.18λ0-0.22λ0.

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