Stable wide-beam broadband end-on-fire antenna

Abstract

The invention discloses a stable wide-beam broadband end-on-fire antenna, which is characterized in that a pair of inclined Y-shaped metal structures and a pair of inverted L-shaped metal structures are symmetrically distributed on two sides of the front and the rear of a dipole in a face-to-face and back-to-back manner, and multi-current distribution and resonance of the inclined Y-shaped metal structures are utilized; the end-on-fire antenna for broadband E-plane beam broadening and broadband impedance matching is realized through the vertical current compensation of the inverted L-shaped metal structure and the reduction of quality factors, and the end-on-fire antenna has the characteristics of high beam broadening degree and good beam width consistency.

Description

Technical Field

[0001] This invention relates to a microwave communication device, and more particularly to an end-fire antenna. Background Technology

[0002] A broadband end-fire antenna is an antenna that maintains end-fire radiation characteristics over a wide frequency band, supporting multi-band fusion while retaining the structural advantages of end-fire antennas, and has been widely used in modern antenna design. However, the limited beamwidth of traditional broadband end-fire antennas restricts their wide-area coverage or wide-angle scanning capabilities, while wide-beam broadband end-fire antennas better meet these requirements. For wide-beam broadband end-fire antennas, the degree of beamwidth broadening and the stability of beamwidth are key capabilities; the former relates to coverage range, and the latter to the consistency of beamwidth across a wide frequency band. Therefore, it is necessary to propose a broadband end-fire antenna with a stable wide beam.

[0003] There are two main types of existing wide-beam broadband end-fire antennas: the first type combines a dipole with two folded-down arms with a metallic ground to achieve beamwidth broadening, but suffers from narrow operating bandwidth and an inability to simultaneously achieve high beamwidth broadening and beamwidth stability; the second method introduces a ring-shaped metal structure below the end-fire electric dipole to form an equivalent magnetic and electric dipole, thereby achieving wide-bandwidth beam radiation, but suffers from lower beamwidth broadening and poor beamwidth stability. Therefore, it is necessary to propose a stable wide-beam broadband end-fire antenna that can simultaneously achieve broadband operation, high beamwidth broadening, and good beam stability over a wide frequency band. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a stable wide-beam broadband end-fire antenna is proposed, which can balance broadband operation and high beamwidth while ensuring good beamwidth consistency within the operating frequency band.

[0005] Technical solution: A stable wide-beam broadband end-fire antenna, comprising: Dielectric substrate; A top-layer metal structure located on the upper surface of the dielectric substrate; the top-layer metal structure includes a pair of planar printed dipole pairs and two oblique Y-shaped metal structures, the two oblique Y-shaped metal structures being symmetrically distributed face-to-face on both sides in front of the planar printed dipole pairs; A bottom metal structure located on the lower surface of the dielectric substrate; the bottom metal structure includes two inverted L-shaped metal structures, which are symmetrically distributed back-to-back on both sides of the rear of the planar printed dipole pair; A balun structure is used to input signals, excite the planar printed dipole pairs, and couple them to the two oblique Y-shaped metal structures and the two inverted L-shaped metal structures.

[0006] Furthermore, the oblique Y-shaped metal structure consists of a horizontal branch, an inclined branch, and a vertical branch, with the centerline of the vertical branch aligned with the left and right open ends of the planar printed dipole pair.

[0007] Furthermore, in the oblique Y-shaped metal structure, the length of the horizontal branches is 0.15λ0~0.17λ0, the length of the inclined branches is 0.15λ0~0.17λ0, and the length of the vertical branches is 0.14λ0~0.16λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0008] Furthermore, the balun structure includes a coplanar coupling line, a stepped annular metal strip, and a metal strip located on the upper surface of the dielectric substrate, and a metal ground located on the lower surface of the dielectric substrate; wherein, along the reverse direction of the antenna end-fire, the coplanar coupling line, the stepped annular metal strip, and the metal strip are connected in sequence, and the top end of the coplanar coupling line is connected to the feed end of the planar printed dipole pair; the inverted L-shaped metal structure consists of a vertical arm and a horizontal arm, and the lower end of the vertical arm is connected to the metal ground.

[0009] Furthermore, the inner sides of the vertical arms of the two inverted L-shaped metal structures are aligned vertically with the left and right open ends of the planar printed dipole pair.

[0010] Furthermore, in the inverted L-shaped metal structure, the length of the vertical arm is 0.08λ0-0.09λ0, and the length of the horizontal arm is 0.07λ0-0.08λ0.

[0011] Furthermore, when the input signal excites the antenna to operate, in the resonant mode of the oblique Y-shaped metal structure, the current is shunted from the oblique stub to the horizontal and vertical stubs. This resonant mode can add a high-frequency resonant point outside the resonant point of the planar printed dipole pair. At the same time, all the vertical current components of the oblique Y-shaped metal structure can effectively broaden the beamwidth of the high-frequency resonant region within the frequency band. The horizontal current component of the oblique Y-shaped metal structure is used to compensate for the far-field signal strength in the end-firing direction, avoiding the formation of a radiation depression region in the end-firing direction.

[0012] Furthermore, the beamwidth flatness within the entire broadband operating frequency band is adjusted by adjusting the tilt of the tilted stub. Specifically, as the downtilt increases, the beamwidth in the low-frequency region increases, while the beamwidth in the high-frequency region decreases.

[0013] Furthermore, the inverted L-shaped metal structure can reduce the quality factor of the radiator, broaden the impedance matching bandwidth, and generate a vertical current on the vertical arm by forming a capacitive coupling with the planar printed dipole pair, which can effectively broaden the beamwidth in the low-frequency region within the frequency band.

[0014] Beneficial Effects: Existing wide-beam broadband end-fire antennas cannot achieve good beamwidth consistency within the operating frequency band, and cannot simultaneously achieve broadband operation and high beamwidth. This invention symmetrically distributes a pair of oblique Y-shaped metal structures and a pair of inverted L-shaped metal structures face-to-face and back-to-back on both sides of the dipole, respectively. Utilizing the multi-current distribution and resonance of the oblique Y-shaped metal structures, and the vertical current compensation and quality factor reduction effect of the inverted L-shaped metal structures, broadband operation is achieved. E It is an end-fire antenna with surface beamwidth broadening and broadband impedance matching, and features high beamwidth broadening and good beamwidth consistency. Attached Figure Description

[0015] Figure 1 A top view of the structure for stabilizing a wide-beam broadband end-fire antenna; Figure 2 A schematic diagram of the structure of a stable wide-beam broadband end-fire antenna from below; Figure 3 For example, the antenna S Parameter simulation results; Figure 4 For example, the antenna E Simulation results of surface beamwidth; Figure 5 For example, the antenna E The simulated radiation patterns are shown, where (a) corresponds to 2.82 GHz, (b) corresponds to 3.16 GHz, and (c) corresponds to 3.50 GHz. Detailed Implementation

[0016] The invention will now be further explained with reference to the accompanying drawings.

[0017] like Figure 1 , Figure 2As shown, a stable wide-beam broadband end-fire antenna mainly consists of a top-layer metal structure on the upper surface and a bottom-layer metal structure on the lower surface of a dielectric substrate 201. The top-layer metal structure includes a pair of planar printed dipole pairs 101, two oblique Y-shaped metal structures 102, a coplanar coupling line 103, a stepped annular metal strip 104, and a metal strip 105. The two oblique Y-shaped metal structures 102 are symmetrically distributed face-to-face in front of the planar printed dipole pairs 101. Each oblique Y-shaped metal structure 102 consists of a horizontal stub with a length between 0.15λ0 and 0.17λ0, an inclined stub with a length between 0.15λ0 and 0.17λ0, and a vertical stub with a length between 0.14λ0 and 0.16λ0. The open end of the inclined stub faces the opposite direction of the antenna end-fire, and the centerline of the vertical stub of the oblique Y-shaped metal structure 102 is aligned with the left and right open ends of the planar printed dipole pairs 101. λ0 is the free space wavelength corresponding to the center frequency. Along the opposite direction of the antenna end-fire, the coplanar coupling line 103, the stepped annular metal strip 104 and the metal strip 105 are connected in sequence, and the top of the coplanar coupling line 103 is connected to the feed terminal of the planar printed dipole pair 101.

[0018] The underlying metal structure includes two inverted L-shaped metal structures 301 and a metal ground 302. The metal ground 302 is a rectangular metal sheet. The two inverted L-shaped metal structures 301 are symmetrically arranged back-to-back, each consisting of a vertical arm with a length between 0.08λ0 and 0.09λ0 and a horizontal arm with a length between 0.07λ0 and 0.08λ0, respectively. The lower end of the vertical arm is connected to the top of the metal ground 302, and the inner side of the vertical arm is aligned vertically with the left and right open ends of the planar printed dipole pair 101.

[0019] The stepped annular metal strip 104, metal strip 105, dielectric substrate 201 and metal ground 302 form a balun structure.

[0020] For the proposed stable wide-beam broadband end-fire antenna, the signal is input through a balun and transmitted to the coplanar coupling line 103 to excite the planar printed dipole pair, and further coupled to the oblique Y-shaped metal structure 102 and the inverted L-shaped metal structure 301. Under the action of the overall structure, wide-bandwidth beam end-fire radiation with high beam width stability is achieved.

[0021] During this process, the oblique Y-shaped metal structure 102 operates in a specific resonant mode, where current is shunted from the oblique stub to the horizontal and vertical stubs. This resonant mode adds a high-frequency resonant point outside the resonant point of the planar printed dipole pair 101, thereby significantly widening the impedance matching bandwidth. Simultaneously, all vertical current components of the oblique Y-shaped metal structure 102 effectively widen the beamwidth in the high-frequency resonant region within the bandwidth. Furthermore, by adjusting the tilt of the oblique stub, the beamwidth flatness within the entire wideband operating frequency band can be adjusted. Specifically, as the downtilt increases, the beamwidth in the low-frequency region increases, while the beamwidth in the high-frequency region decreases. The downtilt refers to the acute angle between the oblique stub and the horizontal line. The horizontal current component of the oblique Y-shaped metal structure 102 is used to compensate for the far-field signal strength in the end-firing direction, avoiding the formation of a radiation depression in the end-firing direction.

[0022] The inverted L-shaped metal structure 301 reduces the quality factor of the radiator and broadens the impedance matching bandwidth. Furthermore, by forming capacitive coupling with the planar printed dipole pair 101 to generate vertical current on the vertical arm, it effectively broadens the beamwidth in the low-frequency region within the frequency band. Therefore, the overall antenna achieves broadband matching and broadband beamwidth, with a high degree of beamwidth and good beamwidth stability across the wide frequency band.

[0023] In this embodiment, the dielectric substrate 201 is RO4003C with a dielectric constant of 3.38. The S-parameter simulation results for this embodiment are as follows: Figure 3 As shown, the 10-dB impedance matching bandwidth covers a range of 2.82 GHz to 3.50 GHz, meaning a relative bandwidth of up to 21.52%. (Simulation results...) E Surface beamwidth as Figure 4 As shown, E The beamwidth reaches 137.5-144.5° within the 10-dB impedance matching bandwidth, indicating that this embodiment achieves a high degree of broadband beamwidth and good beamwidth stability, with beamwidth fluctuations of only ±3.5° within the wide bandwidth. Figure 5 For the antenna at 2.82 GHz, 3.16 GHz, and 3.50 GHz E Surface simulation radiation pattern, E The half-power beamwidths are 138.6°, 138.7°, and 144.5°, respectively, and the cross-polarization levels are all below -40 dB.

[0024] Compared with the best existing technology, the present invention has the advantage of good beamwidth consistency within the operating frequency band, and can take into account both broadband operation and high beamwidth.

[0025] 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 stable wide-beam broadband end-fire antenna, characterized in that, include: Dielectric substrate (201); A top-layer metal structure located on the upper surface of the dielectric substrate (201); the top-layer metal structure includes a pair of planar printed dipole pairs (101) and two oblique Y-shaped metal structures (102), the two oblique Y-shaped metal structures (102) being symmetrically distributed face-to-face on both sides in front of the planar printed dipole pairs (101); The bottom metal structure is located on the lower surface of the dielectric substrate (201); the bottom metal structure includes two inverted L-shaped metal structures (301), which are symmetrically distributed back-to-back on both sides of the rear of the planar printed dipole pair (101). A balun structure is used to input a signal, which excites the planar printed dipole pair (101) and couples it to the two oblique Y-shaped metal structures (102) and the two inverted L-shaped metal structures (301).

2. The stable wide-beam broadband end-fire antenna according to claim 1, characterized in that, The oblique Y-shaped metal structure (102) consists of a horizontal branch, an inclined branch, and a vertical branch, with the center line of the vertical branch aligned with the left and right open ends of the planar printed dipole pair (101).

3. The stable wide-beam broadband end-fire antenna according to claim 2, characterized in that, In the oblique Y-shaped metal structure (102), the length of the horizontal branch is 0.15λ0~0.17λ0, the length of the inclined branch is 0.15λ0~0.17λ0, and the length of the vertical branch is 0.14λ0~0.16λ0, where λ0 is the free space wavelength corresponding to the center frequency.

4. The stable wide-beam broadband end-fire antenna according to claim 2, characterized in that, The balun structure includes a coplanar coupling line (103), a stepped annular metal strip (104), and a metal strip (105) located on the upper surface of the dielectric substrate (201), and a metal ground (302) located on the lower surface of the dielectric substrate (201); wherein, along the reverse direction of the antenna end-fire, the coplanar coupling line (103), the stepped annular metal strip (104), and the metal strip (105) are connected in sequence, and the top end of the coplanar coupling line (103) is connected to the feed end of the planar printed dipole pair (101); the inverted L-shaped metal structure (301) is composed of a vertical arm and a horizontal arm, and the lower end of the vertical arm is connected to the metal ground (302).

5. The stable wide-beam broadband end-fire antenna according to claim 5, characterized in that, The inner sides of the vertical arms of the two inverted L-shaped metal structures (301) are aligned vertically with the left and right open ends of the planar printed dipole pair (101).

6. The stable wide-beam broadband end-fire antenna according to claim 5, characterized in that, In the inverted L-shaped metal structure (301), the length of the vertical arm is 0.08λ0-0.09λ0, and the length of the horizontal arm is 0.07λ0-0.08λ0.

7. The stable wide-beam broadband end-fire antenna according to any one of claims 2-7, characterized in that, When the input signal excites the antenna to work, in the resonant mode of the oblique Y-shaped metal structure (102), the upper current is shunted from the oblique stub to the horizontal and vertical stubs. This resonant mode can add a high-frequency resonant point outside the resonant point of the planar printed dipole pair (101). At the same time, all the vertical current components of the oblique Y-shaped metal structure (102) can effectively widen the beamwidth of the high-frequency resonant region within the frequency band. The horizontal current component of the oblique Y-shaped metal structure (102) is used to compensate for the far-field signal strength in the end-firing direction and avoid the formation of a radiation depression region in the end-firing direction.

8. The stable wide-beam broadband end-fire antenna according to claim 8, characterized in that, The beamwidth flatness within the entire broadband operating frequency band is adjusted by adjusting the tilt angle of the tilted stubs. Specifically, as the downtilt angle increases, the beamwidth in the low-frequency region increases, while the beamwidth in the high-frequency region decreases.

9. The stable wide-beam broadband end-fire antenna according to claim 8, characterized in that, The inverted L-shaped metal structure (301) can reduce the quality factor of the radiator, broaden the impedance matching bandwidth, and generate a vertical current on the vertical arm by forming a capacitive coupling with the planar printed dipole pair (101), which can effectively broaden the beamwidth in the low-frequency region within the frequency band.

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