A planar millimeter-wave dual-beam end-fire antenna with wide beamwidth

Abstract

The present invention discloses a planar millimeter-wave dual-beam end-fire antenna with a wide beam width, comprising a horizontal metal strip resonator, a dielectric substrate, a metal ground, an upper vertical metal strip pair, and a lower vertical metal strip pair. The present invention introduces two pairs of vertical metal strip pairs with different spacings into the dual-beam end-fire antenna implemented by the horizontal metal strip resonator, obtains two pairs of equal-amplitude and in-phase currents through the coupling of reverse currents in the horizontal direction, and obtains wide-beam dual-beam end-to-end radiation in the entire working frequency band after being superimposed with the current source of the horizontal metal strip resonator itself, and takes into account the characteristics of planar structure, compact size, and low profile.

Description

Technical Field

[0001] The invention relates to a microwave communication device, in particular to a millimeter wave dual-beam end-fire antenna. Background Art

[0002] In millimeter wave communication systems, many applications require wireless signals to cover multiple spatial ranges. Based on a single radiation structure, dual-beam end-fire antennas radiate two beams to the spatial area, which can expand the coverage of the signal, reduce the signal blind area, and effectively solve the problem of single-beam antenna coverage area. At the same time, dual-beam end-fire antennas can reduce the number of antennas in the system, thereby reducing the number of base stations, construction costs and maintenance costs. Therefore, they have received great attention in the fields of satellite communications, radar, mobile communications and electronic countermeasures.

[0003] There are two main methods for designing dual-beam end-fire antennas: the first method is to add an oblique electromagnetic metamaterial structure to a wide-beam dipole or butterfly antenna to transform the original single-beam end-radiation into a dual-beam end-radiation. However, this type of dual-beam end-fire antenna has problems such as large size and complex structure, and the 3-dB beam width is also less than 35°. The second method is to obtain a centrally symmetrical current distribution through a diamond or snowflake-shaped metal radiator structure to achieve dual-beam end-radiation, but this type of antenna cannot achieve wide-beam performance within the entire operating frequency band. In general, due to the design method and antenna composition, the beam width of the existing dual-beam end-fire antenna is not wide enough within the entire operating frequency band. Some designs have problems such as complex structure, large size, and high profile, which need to be optimized. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a planar millimeter-wave dual-beam end-fire antenna with a wide beam width is proposed, and the antenna obtains dual-beam end-to-end radiation with a wide beam width in the entire working frequency band.

[0005] Technical solution: A planar millimeter-wave dual-beam end-fire antenna with wide beamwidth, comprising a horizontal metal strip resonator, a dielectric substrate, a metal ground, an upper vertical metal strip pair, and a lower vertical metal strip pair;

[0006] The horizontal metal strip resonator comprises a horizontal metal strip arranged on the upper surface of a dielectric substrate, and also comprises two lumped feeding ports symmetrically distributed on the horizontal metal strip and having opposite phases;

[0007] The metal ground comprises an upper metal ground and a lower metal ground respectively arranged on two surfaces of the dielectric substrate, and a metal through hole array connecting the upper metal ground and the lower metal ground;

[0008] The upper vertical metal strip pair and the lower vertical metal strip pair are respectively arranged on the upper surface and the lower surface of the dielectric substrate; the upper vertical metal strip pair is symmetrical about the center of the horizontal metal strip, and a coupling gap is left with the two ends of the horizontal metal strip; the lower vertical metal strip pair is symmetrical about the center of the horizontal metal strip; one end of the upper vertical metal strip pair is connected to the upper metal ground; one end of the lower vertical metal strip pair is connected to the lower metal ground;

[0009] The upper vertical metal strip pair and the lower vertical metal strip pair have different spacings, which are respectively equivalent to a wavelength corresponding to the central frequency at which the vertical metal strip pair can effectively broaden the beam width.

[0010] Furthermore, the length of the horizontal metal strip is between 0.8 and 0.84 λ0, the width is between 0.04 and 0.06 λ0, and the distances between the two lumped feeding ports and the adjacent ends of the horizontal metal strip are between 0.12 and 0.16 λ0.

[0011] Furthermore, the spacing between two vertical metal strips in the upper vertical metal strip pair is 0.82 ~ 0.86λ0; the spacing between two vertical metal strips in the lower vertical metal strip pair is 0.92 ~ 0.96λ0.

[0012] Furthermore, the length of each vertical metal strip in the upper vertical metal strip pair is between 0.17 and 0.21 λ0, and the width is between 0.04 and 0.06 λ0; the length of each vertical metal strip in the lower vertical metal strip pair is between 0.19 and 0.23 λ0, and the width is between 0.04 and 0.06 λ0.

[0013] Beneficial effects: The existing dual-beam end-fire antenna has the problem that the beam width is not wide enough, and some designs have complex structures, large sizes, and high profiles. The key point of the present invention is to introduce two pairs of vertical metal strips with different spacings into the dual-beam end-fire antenna based on the horizontal metal strip resonator, and obtain two pairs of equal-amplitude and in-phase currents through the coupling of the reverse currents in the horizontal direction. After superposition with the current source of the horizontal metal strip resonator itself, wide-beam dual-beam end-to-end radiation is obtained in the entire working frequency band, and the characteristics of planar structure, compact size, and low profile are taken into account.

[0014] Specifically, two pairs of vertical metal strips disposed on the upper and lower surfaces of the dielectric substrate and located on both sides of the horizontal metal strip resonator generate two pairs of equal-amplitude and in-phase currents due to the coupling of the reverse current on the horizontal metal strips, which can effectively supplement the high azimuth (based on the end-fire direction) radiation of the initial dual-beam end-fire antenna while ensuring the planar structure of the antenna. The length of the upper vertical metal strip is between 0.17 and 0.21 λ0, and the length of the lower vertical metal strip is between 0.19 and 0.23 λ0. Both pairs of vertical metal strips are symmetrical about the center of the dielectric substrate, ensuring the symmetry of the radiation pattern.

[0015] The upper and lower pairs of vertical metal strips have different spacings, which are between 0.82 ~ 0.86 λ0 and 0.92 ~ 0.96λ0, respectively. The spacings are equivalent to a wavelength corresponding to the center frequency of the upper and lower pairs of vertical metal strips that can effectively broaden the beam width. Therefore, two pairs of vertical equal-amplitude anti-phase currents with different spacings can respectively supplement the high azimuth radiation of the low and high frequency bands of the initial dual-beam end-fire antenna, so that the antenna can achieve wide-beam dual-beam end-to-end radiation in the entire working frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the front structure of the antenna of the present invention from a top view;

[0017] Figure 2 It is a schematic diagram of the top and back structure of the antenna of the present invention;

[0018] Figure 3 is a simulation curve of matching and gain of the antenna of the present invention;

[0019] Figure 4 The antenna of the present invention is at three frequency points within the working frequency band E The simulated radiation patterns of the surface, where (a) corresponds to 27.1 GHz, (b) corresponds to 28.75 GHz, and (c) corresponds to 30.4 GHz;

[0020] Figure 5 The antenna without beam width expansion method at three frequency points in the working band E Surface radiation patterns, where (a) corresponds to 25.7 GHz, (b) corresponds to 27.13 GHz, and (c) corresponds to 28.56 GHz. DETAILED DESCRIPTION

[0021] The present invention will be further explained below in conjunction with the accompanying drawings.

[0022] like Figure 1 , Figure 2As shown, a planar millimeter-wave dual-beam end-fire antenna with a wide beam width is mainly composed of a horizontal metal strip resonator 1, a dielectric substrate 2, a metal ground 3, an upper vertical metal strip pair 4 and a lower vertical metal strip pair 5.

[0023] The horizontal metal strip resonator 1 is composed of a horizontal metal strip 11, a lumped feeding port 12 and a lumped feeding port 13, which are integrally arranged on the upper surface of the dielectric substrate 2 and horizontally located at the front end of the antenna end-fire direction. The horizontal metal strip 11 is the main radiator of the antenna, with a length between 0.8 and 0.84 λ0 and a width between 0.04 and 0.06 λ0, where λ0 is the free space wavelength corresponding to the center frequency. The lumped feeding port 12 and the lumped feeding port 13 are the feeding structures of the antenna, which are symmetrically distributed on the horizontal metal strip 11, and the length of the lumped feeding port 12 from the left edge of the horizontal metal strip 11 is equal to the length of the lumped feeding port 13 from the right edge of the horizontal metal strip 11, both of which are between 0.12 and 0.16 λ0. The lumped feeding port 12 and the lumped feeding port 13 have opposite phases and equal characteristic impedances, which are between 48 and 52 Ω.

[0024] The metal ground 3 is composed of an upper metal ground 31 disposed on the upper surface of the dielectric substrate 2, a lower metal ground 32 disposed on the lower surface of the dielectric substrate 2, and a metal through hole array 33 connecting the upper metal ground 31 and the lower metal ground 32. The upper metal ground 31 and the lower metal ground 32 are disposed opposite each other, and their projections in the thickness direction overlap each other. The top edges of the upper metal ground 31 and the lower metal ground 32 are parallel to the horizontal metal strip 11, and the horizontal spacing between the upper metal ground 31 and the lower metal ground 32 is between 0.12 and 0.16λ0. The metal ground 3 serves as the reflection ground of the antenna and also as the system metal ground.

[0025] The upper vertical metal strip pair 4 and the lower vertical metal strip pair 5 are respectively arranged on the upper and lower surfaces of the dielectric substrate 2. The upper vertical metal strip pair 4 is composed of a vertical metal strip 41 and a vertical metal strip 42 which are symmetrical about the center of the horizontal metal strip 11, and a coupling gap with equal spacing is left between the two ends of the horizontal metal strip 11. In the upper vertical metal strip pair 4, the spacing between the two vertical metal strips is 0.82 ~ 0.86 λ0, the length of each vertical metal strip is between 0.17 ~ 0.21 λ0, the width is between 0.04 ~ 0.06 λ0, and one end of each metal strip is vertically connected to the upper metal ground 31. The lower vertical metal strip pair 5 is composed of a vertical metal strip 51 and a vertical metal strip 52 which are symmetrical about the center of the horizontal metal strip 11. In the lower vertical metal strip pair 5 , the spacing between two vertical metal strips is 0.92~0.96 λ0, the length of each vertical metal strip is between 0.19~0.23 λ0, the width is between 0.04~0.06 λ0, and one end of each metal strip is vertically connected to the lower metal ground 32.

[0026] When the antenna is working, the millimeter-wave signal is fed into through the lumped feeding port 12 and the lumped feeding port 13, exciting the horizontal metal strip 11 to produce dual-beam end-to-end radiation. At the same time, part of the signal is coupled to two pairs of vertical metal strips 4 and 5 located on the upper and lower surfaces of the dielectric substrate, forming two pairs of vertical current sources with equal amplitude and phase. The radiation of these sources effectively adjusts the beam width of the original dual-beam radiation pattern. Under the action of the overall structure, millimeter-wave end-fire dual-beam radiation with a wide beam width in the full frequency band is realized.

[0027] In this process, the horizontal metal strip resonator 1 operates in full-wave mode, and the two anti-phase lumped feeding ports 12 and 13 are symmetrically distributed on the horizontal metal strip 11, so that the resonator generates horizontally symmetrical reverse currents. Therefore, under the action of the metal ground 3, dual-beam end-to-end radiation is achieved. The key working mechanism for widening the antenna beam width is that the two pairs of vertical metal strip pairs 4 and 5 located on the upper and lower surfaces of the dielectric substrate 2 and distributed on both sides of the horizontal metal strip resonator 1 are excited in phase within the entire operating frequency band, so that the currents on each pair of vertical metal strips have the characteristics of equal amplitude and the same phase. Therefore, they can be equivalent to two pairs of equal-amplitude and same-phase current radiation sources, and the spacing between each pair of vertical metal strips is one wavelength of the corresponding frequency. According to array theory, a pair of equal-amplitude and same-phase current radiation sources with a spacing of one wavelength can produce a "cross" shape. EThe surface radiation pattern is superimposed and synthesized with the dual-beam end-to-end radiation pattern generated by the horizontal metal strip resonator 1, which can supplement the high azimuth (based on the end-to-end direction) radiation of the corresponding frequency band of the dual-beam end-to-end antenna to a certain extent, so that the half-power beam width of the antenna radiation pattern is improved. The two pairs of vertical metal strips 4 and 5 with different spacings can respectively supplement the high azimuth radiation of the antenna in the low and high frequency bands, so that the antenna can achieve wide-beam dual-beam end-to-end radiation in the entire working frequency band.

[0028] Compared with the best existing technologies, the planar millimeter-wave dual-beam end-fire antenna proposed in the present invention can not only enable the antenna to obtain a wide beam width in the entire operating frequency band, but also take into account the advantages of planar structure, compact size, low profile, and suitability for millimeter-wave applications. In this embodiment, the planar size of the antenna is 0.77 λ0 × 0.28 λ0 (excluding metal ground), and the profile is only 0.019 λ0. The simulated matching response and gain response curves are shown in Figure 2. Figure 3 As shown, it can be seen that the simulated 10-dB impedance matching bandwidth of the antenna is from 27.1 GHz to 30.4 GHz or 11.5% @ 28.75 GHz. Within the 10-dB impedance matching band, the simulated gain of the antenna is between 2.23 - 3.36 dBi. Figure 4 The antenna is shown at two operating frequency edges (27.1 GHz, 30.4 GHz) and at the center frequency (28.75 GHz). E The surface radiation pattern shows that E The 3-dB beam width (single beam) of the antenna is 72.8°, 69.8°, and 58.1° respectively, and the cross-polarization within the 3-dB beam range is -28.43 dB, -27.79 dB, and -27.75 dB respectively. The antenna can achieve stable wide-beam dual-beam end-to-end radiation in the entire operating frequency band. Figure 5 The dual-beam end-fire antenna without two pairs of vertical metal strips is shown at two operating frequency edges (25.7 GHz, 28.56 GHz) and the center frequency (27.13 GHz). E The surface radiation pattern shows that E The 3-dB beamwidth (single beam) of the plane is only 39.1°, 39.1°, and 39.6°. It can be seen that the planar millimeter-wave dual-beam end-fire antenna proposed in the present invention is effective and maintains the characteristics of the antenna planar structure, compact size, and low profile.

[0029] 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 planar millimeter-wave dual-beam end-fire antenna with wide beamwidth, characterized in that: It comprises a horizontal metal strip resonator (1), a dielectric substrate (2), a metal ground (3), an upper vertical metal strip pair (4) and a lower vertical metal strip pair (5); The horizontal metal strip resonator (1) comprises a horizontal metal strip (11) arranged on the upper surface of a dielectric substrate (2), and also comprises two lumped feeding ports symmetrically distributed on the horizontal metal strip (11) and having opposite phases; The metal ground (3) comprises an upper metal ground (31) and a lower metal ground (32) respectively arranged on two surfaces of the dielectric substrate (2), and a metal through hole array (33) connecting the upper metal ground (31) and the lower metal ground (32); The upper vertical metal strip pair (4) and the lower vertical metal strip pair (5) are respectively arranged on the upper surface and the lower surface of the dielectric substrate (2); the upper vertical metal strip pair (4) is symmetrical about the center of the horizontal metal strip (11), and has coupling gaps at both ends of the horizontal metal strip (11); the lower vertical metal strip pair (5) is symmetrical about the center of the horizontal metal strip (11); one end of the upper vertical metal strip pair (4) is connected to the upper metal ground (31); and one end of the lower vertical metal strip pair (5) is connected to the lower metal ground (32); The upper layer vertical metal strip pair (4) and the lower layer vertical metal strip pair (5) have different spacings, which are respectively equivalent to a wavelength corresponding to the central frequency at which the vertical metal strip pair can effectively broaden the beam width.

2. The planar millimeter-wave dual-beam end-fire antenna according to claim 1, characterized in that: The length of the horizontal metal strip (11) is between 0.8λ0 and 0.84λ0, the width is between 0.04λ0 and 0.06λ0, the distances between the two lumped feeding ports and the adjacent ends of the horizontal metal strip (11) are between 0.12λ0 and 0.16λ0, and λ0 is the free space wavelength corresponding to the center frequency.

3. The planar millimeter-wave dual-beam end-fire antenna according to claim 2, characterized in that: The spacing between two vertical metal strips in the upper vertical metal strip pair (4) is 0.82λ0~0.86λ0; The spacing between two vertical metal strips in the lower vertical metal strip pair (5) is 0.92λ0~0.96λ0.

4. The planar millimeter-wave dual-beam end-fire antenna according to claim 2 or 3, characterized in that: The length of each vertical metal strip in the upper vertical metal strip pair (4) is between 0.17λ0 and 0.21λ0, and the width is between 0.04λ0 and 0.06λ0; The length of each vertical metal strip in the lower vertical metal strip pair (5) is between 0.19λ0 and 0.23λ0, and the width is between 0.04λ0 and 0.06λ0.

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