A broadband dual-polarized indoor antenna with beam symmetry widening

Abstract

The application discloses a kind of wideband dual-polarized indoor antennas of beam symmetry broadening, orthogonal mosaic balun is located between orthogonal dual-polarized printed dipole and square metal ground;The bottom end of each balun is used as signal feed port, and the top end of each balun is respectively inserted into the rectangular through hole of a pair of dipoles;Four cross-shaped folded edge metal strips are respectively supported by support above orthogonal dual-polarized printed dipole, and are respectively arranged end to end along the polarization direction of two orthogonal dipoles;Four trapezoidal right-angle bending plates are distributed at four diagonal positions of orthogonal dual-polarized printed dipole, and the bottom is connected with square metal ground.The application acts on orthogonal dual-polarized printed dipole by symmetrically distributed cross-shaped folded edge metal strip and trapezoidal right-angle bending plate, and the effects of the two on high frequency and low frequency E surface, H symmetrical beam broadening and the expansion effect on impedance matching bandwidth are utilized, and wide dual-surface symmetrical beam broadening bandwidth and impedance matching bandwidth are realized.

Description

Technical Field

[0001] This invention relates to a microwave communication device, and more particularly to a broadband dual-polarized indoor antenna. Background Technology

[0002] An indoor antenna is a device used to receive and transmit wireless signals in indoor environments. Its main functions include enhancing signal strength, increasing transmission rates, and reducing interference. Wide-beam indoor antennas can extend their coverage area, effectively reduce signal blind spots, and ensure continuous coverage in multi-room or complex layouts. E noodle, H Wide-beam antennas with symmetrical beamwidth can achieve more uniform coverage in indoor environments. However, in complex indoor or high-density scenarios, broadband dual-polarization is also required to improve channel capacity, adapt to the needs of multi-band and high-density devices, support more concurrent connections, and reduce network congestion. Therefore, the beamwidth of broadband dual-polarized indoor antennas needs to balance... E noodle, H The beamwidth, matching bandwidth, and beamwidth symmetry of the two polarizations form a broadband dual-polarized indoor antenna with symmetrical beamwidth expansion. This type of antenna has important engineering value and significance for indoor communication.

[0003] There are four main methods for widening the beamwidth of existing dual-polarized antennas: The first method is to tilt the metallic ground of the dual-polarized dipole downwards to widen the beamwidth, but this can only widen the beamwidth. H The first method uses a low-profile, dual-polarized magnetoelectric dipole with a small-sized metallic ground plane with metallized blind holes at the four corners to achieve beamwidth, but this method also only achieves limited beamwidth. H Wide beam radiation of the surface E The first type is a square patch antenna with a narrow beamwidth and dual-band characteristics in both matching bandwidth and beamwidth, resulting in a still narrow bandwidth. The second type is a differential probe-fed dual-polarized square patch antenna. It achieves dual-face beamwidth by using the reverse co-polarized currents on four perforated T-shaped strips extending outwards from the patch, and the reverse polarized electric fields from a pair of back-to-back U-shaped strips on the outer side of each T-shaped strip. However, the symmetry of the dual-face beamwidth is poor, and the overall planar size is large, while both the matching bandwidth and beamwidth are narrow. The third type is a slot-coupled fed square dual-polarized patch antenna, which achieves simultaneous beamwidth by adding grounded L-shaped metal strips to the outer four corners of the upper layer. E Face to face H While the beamwidth of the two surfaces is wide, both the matching bandwidth and beamwidth are relatively narrow. In summary, none of the above methods can achieve a wide beamwidth, and some designs cannot achieve double-sided beamwidth or symmetry in double-sided beamwidth. Therefore, it is necessary to propose a broadband dual-polarized indoor antenna with symmetrical beamwidth. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a broadband dual-polarized indoor antenna that achieves double-sided beamwidth is proposed, while taking into account the matching and beamwidth bandwidth and the symmetry of double-sided beamwidth.

[0005] Technical Solution: A broadband dual-polarized indoor antenna with symmetrical beamwidth expansion includes four cross-shaped folded metal strips, an orthogonal dual-polarized printed dipole, an orthogonal interlocking balun, four trapezoidal right-angled bent plates, a square metal ground, and several support pillars. The orthogonal dual-polarized printed dipole includes a dielectric substrate and four orthogonal metal strips with rectangular through holes on the surface of the dielectric substrate. The orthogonal interlocking balun is composed of two vertically arranged baluns orthogonally interlocked, located between the orthogonal dual-polarized printed dipole and the square metal ground. The bottom pins of each balun serve as signal feeds. Electrical ports pass perpendicularly through rectangular slots on a square metal ground; the top pins of each balun are inserted into rectangular through holes of a pair of dipoles; four cross-shaped folded metal strips are supported by pillars above the orthogonal bipolar printed dipoles and are arranged in pairs, end to end along the polarization directions of the two orthogonal dipoles; four trapezoidal right-angled bent plates are distributed at the four opposite corners of the orthogonal bipolar printed dipoles, with their bottoms connected to the square metal ground, and the two bent surfaces of each trapezoidal right-angled bent plate are parallel to the two orthogonal surfaces of the orthogonal interlocking baluns.

[0006] Furthermore, each cross-shaped folded metal strip consists of two equal-length horizontal short strips, one horizontal long strip, and one vertical strip. The horizontal short strips and the horizontal long strip are both located in the horizontal plane, and part of the length of the horizontal long strip overlaps with the dipole metal strip 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 a 90-degree angle along its own axis of symmetry.

[0008] Furthermore, the length of the horizontal short strip is between 0.14λ0 and 0.16λ0, the length of the horizontal long strip is between 0.19λ0 and 0.21λ0, the length of the overlapping part of the horizontal long strip and the dipole is between 0.08λ0 and 0.12λ0, and the length of the vertical strip is between 0.18λ0 and 0.20λ0, where λ0 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 between 0.09λ0 and 0.13λ0, the total length of the lower base is between 0.26λ0 and 0.30λ0, and the height is between 0.20λ0 and 0.24λ0; the distance between the opposite parallel bending surfaces of two adjacent trapezoidal right-angle bent plates is between 0.18λ0 and 0.22λ0.

[0010] Beneficial Effects: Existing dual-polarized indoor antennas cannot achieve a wide beamwidth and suffer from one or more problems, such as the inability to achieve double-sided beamwidth and poor symmetry in double-sided beamwidth. This invention applies symmetrically distributed cross-shaped folded metal strips and trapezoidal right-angle bent plates to an orthogonal dual-polarized printed dipole, utilizing both to target high-frequency and low-frequency beamwidths respectively. E noodle, H The symmetrical beamwidth and impedance matching bandwidth are both extended, resulting in a wider dual-sided symmetrical beamwidth and impedance matching bandwidth.

[0011] Specifically, four cross-shaped folded metal strips are supported by pillars above orthogonal dual-polarized printed dipoles, arranged end-to-end in two groups along the corresponding dipole polarization directions. Each cross-shaped folded metal strip consists of two equal-length horizontal short strips, one horizontal long strip, and one vertical strip located in the horizontal plane. Based on the current distribution characteristics and strip length settings, its main function is at high frequencies. On the one hand, it can extend the impedance matching bandwidth; on the other hand, the pair of cross-shaped folded metal strips in the polarization direction... E The beam broadening effect is achieved by a pair of cross-shaped folded metal strips in the vertical polarization direction. H Beam broadening of the surface has an effect, and E noodle H The beamwidth of the surface is quite similar.

[0012] Four trapezoidal right-angled bent plates are bent at 90 degrees along their own axes of symmetry, with their bottoms connected to a square metal ground, located at the four opposite corners of an orthogonal dual-polarized printed dipole. Their current distribution characteristics constitute two in-phase equivalent magnetic dipoles perpendicular to the polarization direction during operation in any polarization, which can broaden the low-frequency band. E Face and H The beamwidth and the extended impedance matching bandwidth provided for low-frequency resonant points E noodle H The beamwidth of the surface is quite similar. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural diagram of the antenna of the present invention;

[0014] Figure 2 This is a schematic diagram of the projection structure of the antenna of the present invention in the XOZ plane;

[0015] Figure 3 This is a schematic diagram of the orthogonal dual-polarized printed dipole structure in the antenna of the present invention;

[0016] Figure 4 This is a schematic diagram of the balun structure in the antenna of the present invention;

[0017] Figure 5 Embodiments of the present invention S Parameter simulation results;

[0018] Figure 6 The beamwidth simulation results are for an embodiment of the present invention.

[0019] Figure 7 Embodiments of the present invention E noodle, H The surface simulation radiation pattern; where (a) corresponds to 3.7 GHz, (b) corresponds to 4.2 GHz, and (c) corresponds to 5 GHz. Detailed Implementation

[0020] The invention will now be further explained with reference to the accompanying drawings.

[0021] like Figure 1 , Figure 2 As shown, a broadband dual-polarized indoor antenna with symmetrical beamwidth is mainly composed of four cross-shaped folded metal strips 1, orthogonal dual-polarized printed dipoles 2, orthogonal interlocking baluns 3, four trapezoidal right-angled bent plates 4, a square metal ground 5, and four pillars 6.

[0022] The orthogonal dual-polarization printed dipole 2 consists of a dielectric substrate and four orthogonal metal strips with rectangular through-holes on its surface. The rectangular through-holes are located at the feed ends of each metal strip, close to each other. Figure 3 As shown.

[0023] The orthogonally interlocking balun 3 is composed of two vertically arranged baluns orthogonally interlocked. In this embodiment, as shown... Figure 4 As 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. The vertical dielectric substrate 303, as part of itself, has two narrow pins 301 symmetrically formed at its top and two wide pins 305 symmetrically formed at its bottom. The bent metal strip 304 is located on the front side of the vertical dielectric substrate 303 and consists of a vertical portion and a bent portion connecting the top of the vertical portion. The two stepped metal strips 302 are symmetrically distributed on the back side of the vertical dielectric substrate 303, respectively covering the narrow pins 301 at the top and the wide pins 305 at the bottom. One of the stepped metal strips 302 covers the vertical portion of the bent metal strip 304, and the bottom of the vertical portion of the bent metal strip 304 is flush with the bottom of the wide pin 305. The vertical dielectric substrate 303 of the two baluns has a vertical slot in the center. The slot of one balun extends from the lower side of the top horizontal section of the bent metal strip 304 to the bottom 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 of the substrate. The two baluns are connected to each other through the slot.

[0024] The orthogonal mating 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. The four wide pins 305 at the bottom of the orthogonal mating balun 3 pass through the rectangular slots one by one, and their bottom ends serve as signal feed ports. The four narrow pins 301 at the top of the orthogonal mating balun 3 are inserted into the rectangular through holes of the orthogonal dual-polarization printed dipole 2 one by one.

[0025] Four cross-shaped folded metal strips 1 are supported by pillars 6 above orthogonal dual-polarized printed dipoles 2. The four cross-shaped folded metal strips 1 are divided into two groups, arranged end-to-end along the polarization directions of the two orthogonal dipoles. Specifically, each cross-shaped folded metal strip 1 consists of two equal-length horizontal short strips 1-1, one horizontal long strip 1-2, and one vertical strip 1-3. The horizontal short strips 1-1 and the horizontal long strip 1-2 are both located in the horizontal plane. XOY Within the plane, and the length of the horizontal strips 1-2 is within the vertical plane ( XOZ The metal strips inside the plane overlap with the dipole, and the vertical strips 1-3 on the outer side are perpendicular to the horizontal plane.

[0026] Among them, the length of the horizontal short strip 1-1 is between 0.14λ0 and 0.16λ0, the length of the horizontal long strip 1-2 is between 0.19λ0 and 0.21λ0, the length of the overlapping part of the horizontal long strip 1-2 and the dipole is between 0.08λ0 and 0.12λ0, and the length of the vertical strip 1-3 is between 0.18λ0 and 0.20λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0027] The trapezoidal right-angle bent plate 4 is formed by bending an isosceles trapezoidal metal sheet at a 90-degree angle along its own axis of symmetry. Four trapezoidal right-angle bent plates 4 are symmetrically distributed at the four opposite corners of the orthogonal double-polarized printed dipole 2, and their lower bases are connected to the square metal ground 5. The two bending surfaces of each trapezoidal right-angle bent plate 4 are parallel to the two orthogonal surfaces of the orthogonal interlocking balun 3.

[0028] The total length of the upper base of the trapezoidal right-angle bent plate 4 is between 0.09λ0 and 0.13λ0, the total length of the lower base is between 0.26λ0 and 0.30λ0, and the height is between 0.20λ0 and 0.24λ0. The distance between the opposite parallel bending surfaces of two adjacent trapezoidal right-angle bent plates 4 is between 0.18λ0 and 0.22λ0.

[0029] For the proposed broadband dual-polarized indoor antenna with symmetrical beamwidth, the signal is fed in through the orthogonal interlocking balun 3 and coupled to the corresponding polarized dipole in the orthogonal dual-polarized printed dipole 2. Under the combined action of the trapezoidal right-angle bent plate 4, the cross-shaped folded metal strip 1 and the square metal ground 5, a symmetrical wide-beam broadband dual-polarized radiation is formed.

[0030] In this process, the orthogonal dual-polarized printed dipole 2 realizes the basic dual-polarization radiation function. When either polarization is working, the current of the pair of cross-shaped folded metal strips 1 arranged along the polarization direction is mainly distributed on the horizontal long strip 1-2 and the vertical strip 1-3, and the currents on the two horizontal long strips 1-2 in this pair are in phase, while the currents on the two vertical strips 1-3 are out of phase; the currents on the horizontal long strips 1-2 and the vertical strips 1-3 of the same cross-shaped folded metal strip 1 are continuous. The current of the pair of cross-shaped folded metal strips 1 arranged along the vertical polarization direction is mainly distributed on the horizontal short strip 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 currents on the horizontal strips of the aforementioned cross-shaped folded metal strips 1 are out of phase with the dipole current of the corresponding polarization. Based on the aforementioned current distribution characteristics and strip length settings, the cross-shaped folded metal strip 1 primarily operates at high frequencies. On one hand, this expands the impedance matching bandwidth; on the other hand, a pair of cross-shaped folded metal strips 1 in the polarization direction... E The beam broadening effect is achieved by a pair of cross-shaped folded metal strips in the vertical polarization direction. H Beam broadening of the surface has an effect, and E noodle H The beamwidth of the surface is quite similar.

[0031] Each trapezoidal right-angle bent plate 4 has two bending surfaces to ensure good coupling with the corresponding dipole in either polarization state during dual-polarization operation. When operating in either polarization, the current coupled to the trapezoidal right-angle bent plate 4 is mainly distributed on the bending surface perpendicular to the polarization direction. The currents on the two bending surfaces along the polarization direction are out of phase, while the currents on the two bending surfaces perpendicular to the polarization direction are in phase, thus forming two in-phase equivalent magnetic dipoles perpendicular to the polarization direction. Based on the equivalent magnetic dipoles and the height setting of the trapezoidal right-angle bent plate 4, the trapezoidal right-angle bent plate 4 mainly operates at low frequencies. This provides an extended impedance matching bandwidth for the low-frequency resonant point and broadens the low-frequency band. E Face and H Surface beamwidth.

[0032] In summary, for any polarization, the low-frequency and high-frequency bands... E Face to face H The beamwidth is broadened to a similar degree, and the matching bandwidth of the dual polarization is broadened, thus enabling the realization of a broadband dual-polarized indoor antenna with symmetrical beamwidth.

[0033] The dielectric substrate used in this embodiment is RO4003C with a dielectric constant of 3.55, and the overall antenna element size is 1.06λ0 × 1.06 λ0 × 0.37 λ0. The simulation results of the matching response in this embodiment are as follows: Figure 5 As shown, the operating frequency band covers 3.27 GHz to 5.27 GHz, with a relative bandwidth of 46.8%. Simulation results... E noodle, H Surface beamwidth as Figure 6 As shown, E Wide-beamwidths (beamwidths exceeding 110°) range in frequency from 3.67 GHz to 5.37 GHz. H The wide beamwidth with a beamwidth of 110° or more has a frequency range of 3.67 GHz to 5.5 GHz, and the relative bandwidth of the double-sided wide beamwidth overlapping with the operating frequency band is 35.8%, i.e., 3.67 GHz to 5.27 GHz. Figure 7 When the antenna is in operation, at 3.7 GHz, 4.2 GHz, and 5 GHz... E Face and H Surface simulation radiation pattern, E The half-power beamwidths are 113.6°, 142.2°, and 148°, respectively. H The half-power beamwidths are 116°, 128.6°, and 125.3°, respectively, with cross-polarization levels all below -17 dB. Compared to the best prior art, this invention achieves a wider double-sided beamwidth and exhibits better symmetry in double-sided beamwidth broadening.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A broadband dual-polarized indoor antenna with symmetrical beam stretching, characterized in that, It includes four cross-shaped folded metal strips (1), orthogonal bipolar printed dipoles (2), orthogonal interlocking baluns (3), four trapezoidal right-angled bent plates (4), a square metal ground (5), and several pillars (6). The orthogonal dual-polarization printed dipole (2) includes a dielectric substrate and four orthogonal metal strips with rectangular through holes on the surface of the dielectric substrate; The orthogonal interlocking balun (3) is composed of two vertically arranged baluns orthogonally interlocked. The orthogonal interlocking balun (3) is located between the orthogonal dual-polarized printed dipole (2) and the square metal ground (5). The bottom pin of each balun serves as a signal feed port and passes vertically through the rectangular slot on the square metal ground (5). The top pin of each balun is inserted into the rectangular through hole of a pair of dipoles respectively. Four cross-shaped folded metal strips (1) are supported by pillars (6) above orthogonal bipolar printed dipoles (2), and are divided into two groups, arranged end to end along the polarization direction of the two orthogonal dipoles respectively; Four trapezoidal right-angled bending plates (4) are distributed at the four opposite corners of the orthogonal double-polarized printed dipole (2), and the bottom is connected to the square metal ground (5). The two bending surfaces of each trapezoidal right-angled bending plate (4) are parallel to the two orthogonal surfaces of the orthogonal interlocking balun (3); Each cross-shaped folded metal strip (1) consists of two equal-length horizontal short strips (1-1), one horizontal long strip (1-2), and one vertical strip (1-3). The horizontal short strip (1-1) and the horizontal long strip (1-2) are both located in the horizontal plane, and part of the length of the horizontal long strip (1-2) overlaps with the dipole metal strip in the vertical plane. The vertical strip (1-3) located on the outside is perpendicular to the horizontal plane.

2. The broadband dual-polarized 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 a 90-degree angle along its own axis of symmetry.

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

4. The broadband dual-polarized indoor antenna according to claim 3, characterized in that, The total length of the upper base of the trapezoidal right-angle bent plate (4) is between 0.09λ0 and 0.13λ0, the total length of the lower base is between 0.26λ0 and 0.30λ0, and the height is between 0.20λ0 and 0.24λ0; the distance between the parallel bending surfaces of two adjacent trapezoidal right-angle bent plates (4) is between 0.18λ0 and 0.22λ0.

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