Broadband wide-beam decoupling antenna for base station

Abstract

The invention discloses a broadband wide-beam decoupling antenna facing a base station. The broadband wide-beam decoupling antenna is composed of a top-layer additional structure, a dipole, a balun, a trapezoidal grounding plate, a metal ground and a supporting column. Taking a 1 * 2 antenna array as an example, the top-layer additional structure and the trapezoidal grounding plate are used as additional structures of the dipole antenna array and are distributed above, in the middle and on two sides of the dipole antenna array, and a metal strip of the top-layer additional structure and the trapezoidal grounding plate are respectively used for decoupling, beam broadening and matching adjustment. According to the technical scheme, the effect of the H-shaped metal strip of the top layer additional structure on H-plane wave beam broadening is combined with balun feed, the wide wave beam width bandwidth and the decoupling bandwidth are synchronously improved, and the comprehensive working bandwidth, the in-band wave beam width stability and the structural complexity can be considered.

Description

Technical Field

[0001] The invention relates to a microwave communication device, in particular to a wide bandwidth beam decoupling antenna facing a base station. Background Art

[0002] Base station antennas are key components in mobile communication systems. Broadband base station antennas can cover multiple frequency bands, which is conducive to the compatibility of multiple communication standards, improving spectrum efficiency and reducing the number of base station antennas. At the same time, half-power beamwidth is an important indicator of base station antennas. Wide beamwidth is conducive to increasing the coverage area and reducing the number of sectors; low mutual coupling base station antennas are conducive to ensuring that the base station antenna array maintains normal operation in terms of matching, radiation pattern and efficiency. However, broadband base station antennas require that the half-power beamwidth and low mutual coupling between units can maintain a wide operating bandwidth, that is, the performance needs to meet broadband matching, broadband half-power beamwidth and broadband decoupling, so it is a great challenge, but it has important engineering application value.

[0003] Existing base station antennas do not have the technology to simultaneously meet the requirements of wide bandwidth beam and broadband decoupling. Currently, there are two methods for widening the bandwidth corresponding to the wide beam width: the first is to combine the bent dipole arm with the addition of metal walls on both sides, and construct magnetic dipoles with different working frequencies inside the dipole and between the dipole arm and the metal wall, thereby achieving wide bandwidth beam broadening, but the high-frequency magnetic dipole radiation is weak, resulting in the beam broadening band not being able to cover the entire matching bandwidth; the second solution is to add a metal cylinder just below the end of the bent metal arm of the broad-leaf magneto-electric dipole, and expand the beam broadening bandwidth by regulating the vertical current on the dipole arm at different frequencies with the metal cylinder, but the intra-band beam width fluctuates greatly. There are two methods to broaden the antenna decoupling bandwidth: the first is to superimpose a composite dielectric layer and an array decoupling layer, combined with an enclosing distribution of multi-branch resonators, to achieve a reduction in the mutual coupling of the overall frequency band, but the decoupling bandwidth needs to be further broadened, and the overall structural complexity is relatively high; the second is to place metal strip resonators on the front, back and top of the dipole, thereby introducing multiple mutual coupling zero points to achieve a broadened decoupling bandwidth, but due to the large number of dielectric substrates used, problems such as complex structure and high cost arise.

[0004] The above-mentioned method of increasing the wide beam width bandwidth or the decoupling bandwidth can only achieve unilateral bandwidth widening of each, and cannot simultaneously achieve the widening of the common bandwidth of the two. Summary of the invention

[0005] Purpose of the invention: In view of the above-mentioned prior art, a wide-bandwidth beam decoupling antenna for base stations is proposed, which can simultaneously meet the requirements of wide-bandwidth beam and broadband decoupling, and can take into account the comprehensive working bandwidth, in-band beam width stability and structural complexity.

[0006] Technical solution: A wide bandwidth beam decoupling antenna for a base station, comprising a top-layer additional structure, N dipoles, N baluns, (N+1) trapezoidal ground plates, and a metal ground; N is a natural number greater than or equal to 2; The top additional structure includes a top dielectric substrate, (N+1) metal strips are evenly spaced along a straight line on the upper surface of the top dielectric substrate, and two H-shaped metal strips are symmetrically distributed about the straight line in the gap between two adjacent metal strips; The dipole includes a middle dielectric substrate and a half-wave oscillator located on the lower surface of the middle dielectric substrate; N dipoles are horizontally arranged below the top additional structure along a straight line, and the center of each dipole is respectively aligned with the midpoint of the gap between the metal strips; Each balun is connected to a dipole and a metal ground respectively; (N+1) trapezoidal ground plates are arranged in parallel with equal spacing along the polarization direction and are respectively located at the midpoint of the gap between two adjacent dipoles and outside the dipoles at both ends.

[0007] Furthermore, in the dipole, a pair of square air holes are provided near the central feeding position of the two arms of the half-wave oscillator; The balun includes a vertical dielectric substrate, a bent metal strip, and two stepped metal strips; wherein, as a part of the vertical dielectric substrate, the top of the vertical dielectric substrate symmetrically forms two narrow pins, and the bottom of the vertical dielectric substrate symmetrically forms two wide pins; the bent metal strip is located on the front side of the vertical dielectric substrate, and the bent metal strip is composed of a vertical portion and a bent portion connected to the top of the vertical portion; the two stepped metal strips are symmetrically distributed on the back side of the vertical dielectric substrate, and cover a narrow pin and a wide pin respectively; the area of ​​one of the stepped metal strips covers the vertical portion of the bent metal strip, and the bottom end of the vertical portion of the bent metal strip is flush with the bottom end of the wide pin; The main body of the metal ground is a rectangular metal sheet; the balun is respectively inserted into two square air holes of a dipole through two narrow pins, and is respectively inserted into corresponding slots on the rectangular metal sheet through two wide pins.

[0008] Furthermore, the distance between the top additional structure and the metal ground is 0.35λ 0 -0.39λ 0 Between 0 is the free space wavelength corresponding to the center frequency; the length of the metal strip is 0.28λ 0 -0.32λ 0 The length of the left and right arms of the H-shaped metal strip is 0.14λ 0 -0.18λ 0 The intermediate horizontal length is 0.11λ 0 -0.15λ 0 between.

[0009] Furthermore, the height between the dipole and the metal ground is 0.23λ 0 -0.25λ 0 ; The height of the trapezoidal ground plate is 0.19λ 0 -0.23λ 0 The width of the upper base is 0.06λ 0 -0.10λ 0 Between, the bottom width is 0. 30λ 0 -0.34λ 0 between.

[0010] Beneficial effects: Existing wide beam or decoupled base station antennas cannot simultaneously meet the requirements of wide bandwidth beam and broadband decoupling, and can only achieve broadband decoupling or wide bandwidth beam separately, and have problems such as relatively narrow comprehensive working bandwidth, poor in-band beam width stability or complex structure. Taking a 1*2 antenna array as an example, the present invention uses the top-layer additional structure and the trapezoidal ground plate as additional structures of the dipole antenna array, which are distributed above, in the middle and on both sides of the dipole array, and utilizes the triple effects of the metal strips of the top-layer additional structure and the trapezoidal ground plate on decoupling, beam broadening and matching adjustment, and the H-shaped metal strips of the top-layer additional structure on H The effect of surface beam broadening, combined with balun feeding, can achieve the simultaneous improvement of wide beam width bandwidth and decoupling bandwidth, and can take into account the comprehensive working bandwidth, in-band beam width stability and structural complexity.

[0011] Specifically, the three metal strips of the top additional structure are symmetrically arranged along a straight line just above the dipole array, wherein the middle metal strip can not only form a new coupling path between the two dipoles to offset the high-frequency coupling zero point, but also combine with the metal strips on both sides to each dipole. E The surface radiation forms an oblique pulling effect, producing high-frequency bands in a wide frequency band. E At the same time, the three metal strips have an adjusting effect on the resonant frequency and matching degree of the antenna, which is beneficial to width matching.

[0012] The four H-shaped metal strips of the top additional structure are aligned with the two gaps between the metal strips and are symmetrically arranged on both sides of the metal strips. H The oblique traction effect of surface radiation can widen the H Surface beam width.

[0013] The three trapezoidal ground plates are arranged linearly and symmetrically along the polarization direction, respectively located in the middle and on both sides of the gap between the two dipoles. The middle trapezoidal ground plate can not only adjust the coupling path to generate a coupling zero point in the low frequency band of the working frequency band, but also can couple with the corresponding dipoles together with the trapezoidal ground plates on both sides to form a new resonant mode located in the low frequency band of the working frequency band. In addition, the multiple anti-phase vertical currents obtained by coupling the trapezoidal ground plate can greatly increase the resonant mode near the low frequency resonance point. E Surface beam width.

[0014] The balun consists of two narrow pins, a stepped metal strip, a vertical dielectric substrate, a bent metal strip, and two wide pins. The narrow pin and the wide pin are inserted into the dipole and the metal ground respectively, and the stepped metal strip is connected to the half-wave oscillator and the metal ground. The balun can provide differential excitation for the dipole, adjust the matching, and provide structural support for the dipole. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the three-dimensional structure of the wide bandwidth beam decoupling antenna for base stations of the present invention; Figure 2 It is a schematic diagram of the top-layer additional structure of the wide bandwidth beam decoupling antenna for base stations of the present invention; Figure 3 A schematic diagram of a dipole structure of a wide bandwidth beam decoupling antenna for a base station according to the present invention; Figure 4 A schematic diagram of the balun structure of the wide bandwidth beam decoupling antenna for base stations of the present invention; Figure 5 It is a schematic diagram of the metal ground structure of the wide bandwidth beam decoupling antenna for base stations of the present invention; Figure 6 The present invention is different from the one without adding additional structure. S Parameter simulation result comparison chart; Figure 7 The present invention is different from the one without adding additional structure. E noodle H Comparison chart of surface simulation beam width; Figure 8 For the embodiment of the present invention E noodle H Surface simulation radiation patterns, where (a) corresponds to 3.6 GHz, (b) corresponds to 4 GHz, and (c) corresponds to 4.4 GHz. DETAILED DESCRIPTION

[0016] The present invention will be further explained below in conjunction with the accompanying drawings.

[0017] like Figure 1As shown, a wide bandwidth beam decoupling antenna for a base station is composed of a top-level additional structure 1, a dipole 2, a balun 3, a trapezoidal ground plate 4, a metal ground 5 and a support 6.

[0018] This embodiment provides a 1*2 antenna array, such as Figure 2 As shown, the top-layer additional structure 1 is symmetrical in the center as a whole, and is composed of a top-layer dielectric substrate 101, three metal strips 102 and four H-shaped metal strips 103 located on the upper surface of the top-layer dielectric substrate 101. The three metal strips 102 are evenly spaced along a straight line, and the four H-shaped metal strips 103 are aligned with the two gaps between the metal strips 102 and are symmetrically arranged on both sides of the metal strips 102. The top-layer additional structure 1 is supported at the top of the overall antenna by four pillars 6 located at the four corners of the top-layer dielectric substrate 101, and the bottom end of the pillar 6 is connected to the metal ground 5. The distance between the top-layer additional structure 1 and the metal ground 5 is 0.35λ. 0 -0.39λ 0 Between 0 is the free space wavelength corresponding to the center frequency; the length of the metal strip 102 is 0.28λ 0 -0.32λ 0 The length of the left and right arms of the H-shaped metal strip 103 is between 0.14λ 0 -0.18λ 0 The intermediate horizontal length is 0.11λ 0 -0.15λ 0 between.

[0019] like Figure 3 As shown, the dipole 2 is composed of a middle dielectric substrate 201, a half-wave oscillator 202 and two square air holes 203, and is symmetrical as a whole. The half-wave oscillator 202 is located on the lower surface of the middle dielectric substrate 201, and the two arms of the half-wave oscillator 202 are arranged in a straight line. The two square air holes 203 are symmetrically located on the two arms of the half-wave oscillator 202 and close to the central feeding point. The two dipoles 2 are horizontally arranged below the top additional structure 1, and the centers are respectively opposite to the midpoints of the gaps between the metal strips 102. The height between the dipole 2 and the metal ground 5 is 0.23λ. 0 -0.25λ 0 .

[0020] like Figure 4As shown, the balun 3 is composed 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 a narrow pin 301 and a wide pin 305 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.

[0021] like Figure 5 As shown, the main body of the metal ground 5 is a rectangular metal sheet 501, and two groups of slots are opened on the rectangular metal sheet 501 for inserting the wide plug 305 at the bottom of the balun 3. In each group of slots, one is located in a rectangular wide slot 502. The other is located in a rectangular narrow slot 503. The size of the rectangular wide slot 502 is adapted to the wide plug 305 with the vertical portion of the bent metal strip 304.

[0022] like Figure 1 As shown, two baluns 3 are respectively inserted into two square air holes 203 of a dipole 2 through two narrow pins 301, and are respectively inserted into the rectangular wide slot 502 and the rectangular narrow slot 503 of the metal ground 5 through two wide pins 305, so as to connect the stepped metal strip 302 with the half-wave oscillator 202 and the metal ground 5. Three trapezoidal ground plates 4 are arranged in parallel with equal spacing along the polarization direction (i.e., the arrangement direction of the two arms of the dipole), and are respectively located at the midpoint and both sides of the gap between the two dipoles 2. The height of the trapezoidal ground plate 4 is 0.19λ. 0 -0.23λ 0 The width of the upper base is 0.06λ 0 -0.10λ 0 Between, the bottom width is 0. 30λ 0 -0.34λ 0 between.

[0023] In the above structure, the dipole 2, balun 3 and metal ground 5 constitute the main body of the antenna unit; the top additional structure 1 and three trapezoidal ground planes 4 constitute the additional structure of the dipole antenna array. The bent metal strip 304 of the balun 3, the vertical dielectric substrate 303 and the stepped metal strip 302 constitute the microstrip feed line of the antenna.

[0024] For the above-mentioned wide bandwidth beam decoupling antenna, the signal is fed from the microstrip feed line of the balun 3 and coupled to each dipole 2. Under the joint action of the dipole 2 and its additional structure, a base station antenna that satisfies both wide bandwidth beam and broadband decoupling is realized.

[0025] In this process, the middle metal strip 102 of the top additional structure 1 can bring a new coupling path to the two dipoles 2, thereby offsetting the original coupling path to form a high-frequency coupling zero point, which helps to widen the decoupling bandwidth; on the other hand, combined with the metal strips 102 on both sides, the E Surface radiation has an oblique pulling effect, so it can be widened E The beam width, especially in the high frequency band E The surface beam width can provide a basis for broadband beam broadening. At the same time, the three metal strips 102 on the top layer have an adjustment effect on the resonant frequency and matching degree of the antenna, which is beneficial to width matching. The four H-shaped strips 103 on the top layer H Surface radiation has an oblique pulling effect, thus widening it to a certain extent H Surface beam width.

[0026] The trapezoidal ground plane 4 in the middle can adjust the coupling path and generate a coupling zero point in the low frequency band of the working frequency band, which helps to widen the decoupling bandwidth; on the other hand, it couples with the corresponding dipole 2 together with the trapezoidal ground planes 4 on both sides to form a new resonance mode in the low frequency band of the working frequency band, which is conducive to expanding the matching bandwidth. At the same time, the trapezoidal ground plane 4 couples to obtain an anti-phase vertical current, and the trapezoidal surface is conducive to constructing multiple vertical currents, which can greatly increase the area near the low-frequency resonance point. E The surface beam width also provides the basis for broadband beam broadening.

[0027] Therefore, under the combined effect of the top additional structure 1 and the trapezoidal ground plane 4, the dipole array can simultaneously obtain broadband decoupling, wide bandwidth beam and broadband matching, and the broadband stability of the intra-band beam is good. The balun 3 under the dipole 2 can provide differential excitation for the dipole, adjust the matching, and provide structural support for the dipole.

[0028] The dielectric substrate used in this embodiment is RO4003C, the dielectric constant is 3.55, and the antenna size is 1.5λ 0 ×1.0λ 0 × 0.37λ 0 . Figure 6 The present embodiment is compared with the case without additional structure. S Parameter simulation results. Figure 6It can be seen that before adding the additional structure, the matching frequency band of the antenna covers 3.69-5.13 GHz, that is, the relative bandwidth is 30%, and the maximum coupling degree between units in the matching frequency band is -10 dB. After adding the additional structure in the present invention, the matching frequency band covers 3.28-4.8 GHz, that is, the relative bandwidth is widened to 37.6%, the maximum coupling degree is only -22 dB, and the corresponding decoupling bandwidth can reach 40.6%. Figure 7 The present embodiment is compared with the case without additional structure. E noodle, H Simulation results of the beam width without additional structure, in the range of 3.8-4.7GHz E The beam width is between 46° and 73°. H The beam width is between 85° and 105°, and after adding additional structures, it is in the range of 3.3-4.7 GHz. E The surface beam width is between 100° and 112°. H The beam width is between 98° and 122°, and it can be seen that the beam width is significantly widened, and the wideband E Surface beam stability has also been improved. Figure 8 are the simulated radiation patterns of this embodiment at 3.6 GHz, 4 GHz, and 4.4 GHz, E The half-power beamwidths are 100°, 103°, and 103° respectively. H The half-power beam width is 103°, 110°, and 119°, and the cross-polarization level is low. Compared with the prior art, the present invention can simultaneously improve the wide beam width bandwidth and decoupling bandwidth, and can take into account the comprehensive working bandwidth, in-band beam width stability and structural complexity.

[0029] The 1*2 antenna array of this embodiment can be expanded to a 1*N structure.

[0030] 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 wide bandwidth beam decoupling antenna for a base station, characterized in that: It includes a top-layer additional structure (1), N dipoles (2), N baluns (3), (N+1) trapezoidal ground planes (4), and a metal ground (5); N is a natural number greater than or equal to 2; The top additional structure (1) comprises a top dielectric substrate (101), (N+1) metal strips (102) are evenly spaced and arranged along a straight line on the upper surface of the top dielectric substrate (101), and two H-shaped metal strips (103) are symmetrically distributed about the straight line in the gap between two adjacent metal strips (102); The dipole (2) comprises a middle dielectric substrate (201) and a half-wave oscillator (202) located on the lower surface of the middle dielectric substrate (201); the N dipoles (2) are horizontally arranged below the top additional structure (1) along a straight line, and the center of each dipole (2) is directly opposite to the midpoint of the gap between the metal strips (102); Each balun (3) is respectively connected to a dipole (2) and a metal ground (5); (N+1) trapezoidal ground plates (4) are arranged in parallel at equal intervals along the polarization direction and are respectively located at the midpoint of the gap between two adjacent dipoles (2) and outside the dipoles (2) at both ends.

2. The base station-oriented wide bandwidth beam decoupling antenna according to claim 1, characterized in that: In the dipole (2), two arms of the half-wave oscillator (202) are provided with a pair of square air holes (203) near the central feeding position; The balun (3) comprises a vertical dielectric substrate (303), a bent metal strip (304), and two stepped metal strips (302); wherein, as a part of the vertical dielectric substrate (303), the top of the vertical dielectric substrate (303) symmetrically forms two narrow pins (301), and the bottom of the vertical dielectric substrate (303) symmetrically forms two wide pins (305); 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 portion and a bent portion connected to 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), and cover a narrow pin (301) and a wide pin (305) respectively; an area of ​​one of the stepped metal strips (302) covers the vertical portion of the bent metal strip (304), and the bottom end of the vertical portion of the bent metal strip (304) is flush with the bottom end of the wide pin (305); The main body of the metal ground (5) is a rectangular metal sheet (501); the balun (3) is respectively inserted into two square air holes (203) of a dipole (2) through two narrow pins (301), and is respectively inserted into corresponding slots on the rectangular metal sheet (501) through two wide pins (305).

3. The base station-oriented wide bandwidth beam decoupling antenna according to claim 1 or 2, characterized in that: The distance between the top additional structure (1) and the metal ground (5) is between 0.35λ0-0.39λ0, where λ0 is the free space wavelength corresponding to the center frequency; the length of the metal strip (102) is between 0.28λ0-0.32λ0, the length of the left and right arms of the H-shaped metal strip (103) is between 0.14λ0-0.18λ0, and the middle horizontal length is between 0.11λ0-0.15λ0.

4. The base station-oriented wide bandwidth beam decoupling antenna according to claim 3, characterized in that: The height between the dipole (2) and the metal ground (5) is 0.23λ0-0.25λ0; the height of the trapezoidal ground plate (4) is between 0.19λ0-0.23λ0, the upper base width is between 0.06λ0-0.10λ0, and the lower base width is between 0.30λ0-0.34λ0.

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