阅读说明：本技术 一种±45°双极化毫米波阵列天线 (+/-45-degree dual-polarized millimeter wave array antenna ) 是由 杨清凌 高式昌 文乐虎 苏海滨 于 2020-11-27 设计创作，主要内容包括：本发明公开了一种±45°双极化毫米波阵列天线,包括从下到上依次层叠设置的第一金属层、第一介质层、第二金属层、粘结层、第三金属层、第二介质层和第四金属层,在第一金属层上蚀刻有基片集成波导腔体下层金属阵列。本发明所公开的±45°双极化毫米波阵列天线,采用微带和基片集成波导混合设计,在有限的空间中设计出带馈电网络的双极化阵列天线。通过角馈的方式对基片集成波导腔体进行馈电,获得了较好的端口隔离度和交叉极化鉴别率。采用了四分之一圆形切角的贴片增加了天线的工作带宽。(The invention discloses a +/-45-degree dual-polarized millimeter wave array antenna which comprises a first metal layer, a first dielectric layer, a second metal layer, a bonding layer, a third metal layer, a second dielectric layer and a fourth metal layer which are sequentially stacked from bottom to top, wherein a lower metal array of a substrate integrated waveguide cavity is etched on the first metal layer. The +/-45-degree dual-polarized millimeter wave array antenna disclosed by the invention adopts a hybrid design of a micro-strip and a substrate integrated waveguide, and a dual-polarized array antenna with a feed network is designed in a limited space. The substrate integrated waveguide cavity is fed in an angle feeding mode, and good port isolation and cross polarization discrimination are obtained. The use of quarter-circle corner cut patches increases the operating bandwidth of the antenna.)

1. The utility model provides a 45 double polarization millimeter wave array antenna which characterized in that: the substrate integrated waveguide cavity comprises a first metal layer, a first dielectric layer, a second metal layer, a bonding layer, a third metal layer, a second dielectric layer and a fourth metal layer which are sequentially stacked from bottom to top, wherein a lower metal array of a substrate integrated waveguide cavity is etched on the first metal layer, N cascaded feed networks and M power dividers are arranged, N is an even number larger than or equal to 4, M is a natural number larger than or equal to 2, the two cascaded feed networks are connected together through the power dividers, the substrate integrated waveguide cavity adopts an angular feed and square structure with two ports, signals respectively flow in from the two cascaded feed networks on two sides of the substrate integrated waveguide cavity through the two ports, a substrate integrated waveguide cavity metalized through hole, a cascaded feed network grounding patch metalized through hole and a power divider grounding patch metalized through hole are arranged in the first dielectric layer, the second metal layer and the third metal layer are floor layers, and the substrate integrated waveguide cavity array position is opposite to that of the substrate integrated waveguide cavity array, The array of the crossed cross slots with the same quantity, and the direction of each crossed cross slot is consistent with the direction of the diagonal line of the corresponding substrate integrated waveguide cavity, the substrate integrated waveguide cavity excites the crossed cross slots, the second metal layer and the third metal layer are bonded into a whole by the bonding layer, the array of the microstrip radiation patches with the same quantity and the position opposite to the crossed cross slot array is etched on the fourth metal layer, the direction of the microstrip radiation patches is consistent with the direction of the corresponding crossed cross slots, and the microstrip radiation patches generate dual-polarization radiation under the excitation of the crossed cross slots.

2. The ± 45 ° dual polarized millimeter wave array antenna according to claim 1, wherein: the cascade feed network is composed of microstrip lines, and a grounding patch is arranged at the bent part of the microstrip lines.

3. The ± 45 ° dual polarized millimeter wave array antenna according to claim 1, wherein: the power divider is composed of microstrip lines, two microstrip arms of the power divider are respectively connected with a cascade feed network, and a grounding patch is arranged between the two microstrip arms.

4. The ± 45 ° dual polarized millimeter wave array antenna according to claim 1, wherein: the substrate integrated waveguide cavity is realized by a square metallized through hole, the substrate integrated waveguide cavity also comprises a microstrip line, and two ports exciting the substrate integrated waveguide cavity can respectively generate TE in the cavity₁₂₀And TE₂₁₀A mode electric field.

5. The ± 45 ° dual polarized millimeter wave array antenna according to claim 1, wherein: the four micro-strip radiation patches etched on the fourth metal layer are respectively provided with a quarter-circle corner cut and are connected through a cross micro-strip.

6. The ± 45 ° dual polarized millimeter wave array antenna according to claim 1, wherein: the array antenna contains 2 x 8 antenna elements comprising a substrate integrated waveguide cavity with a center frequency of 28 GHz.

7. The ± 45 ° dual polarized millimeter wave array antenna according to claim 5, wherein: the first dielectric layer is RO4003C, the dielectric constant is 3.55, the loss tangent is 0.0027, and the thickness is 0.305 mm; the second medium layer is also RO4003C, and the thickness is 0.508 mm; the adhesive layer is RO4450F, the thickness is 0.2mm, the dielectric constant is 3.52, and the loss tangent is 0.004; the first, second, third and fourth metal layers are all metal copper clad layers, and the thicknesses are all 0.5 ounce; the cross section height of the whole array antenna is 0.076 free space wavelengths, and the size of a substrate integrated waveguide cavity is 5.4 mm multiplied by 5.4 mm; the length and the width of the crossed cross gap are respectively 2.84 mm and 0.3 mm; the width of the microstrip radiation patch is 2.19 mm, the radius of a quarter of a circle corner cut of the microstrip radiation patch is 1.46 mm, the width of a gap between the microstrip radiation patch and the patch is 0.45mm, and the width of the cross-shaped thin microstrip is 0.17 mm.

Technical Field

The invention belongs to the technical field of microwave and millimeter wave antennas, and particularly relates to a +/-45-degree dual-polarized millimeter wave array antenna in the field.

Background

In wireless communication systems, antennas are key components for signal reception and transmission. With the development of wireless mobile communication technology, microwave millimeter wave antennas are required to realize the characteristics of dual polarization, low profile, low cost, easy processing and the like while ensuring good electrical performance.

The +/-45-degree dual-polarized antenna is mainly realized by a symmetrical oscillator, a waveguide cross slot, a printed microstrip antenna and the like. The dipole antenna has the advantages of simple structure, wide bandwidth, low cross polarization, half-power lobe width and the like; the disadvantages are that it is difficult to realize a low profile in the high-frequency millimeter wave band and to perform feeding. The waveguide cross slot has the characteristics of low cross polarization level, high radiation efficiency and the like; the disadvantage is that the feed network is bulky, and it is difficult to realize dual-polarized feed network on a single layer when designing the antenna array. The printed microstrip antenna has the advantages of simple processing, low section and the like, but has the disadvantages of narrow bandwidth, high loss and low radiation efficiency. In recent years, as a new antenna design structure, the substrate integrated waveguide can replace a metal waveguide in a millimeter wave frequency band, is easy to process and integrate with a planar circuit, and is an excellent millimeter wave antenna design structure. The dual-polarized feed network is realized on a single-layer PCB by utilizing microstrip lines, and the design of an antenna structure by utilizing the substrate integrated waveguide is a better choice for the design of a dual-polarized millimeter wave antenna.

For example, it is proposed to design +45 ° and ‒ 45 ° millimeter wave antenna elements, respectively, and then form linear arrays, respectively, and stagger the linear arrays to realize a ± 45 ° dual polarization planar array. The reported antenna elements have slotted microstrip patches or 45 ° slanted slot elements. The design has the advantages that the feed network has no cross and is easy to design. However, these structures have the disadvantages of large antenna size, low antenna efficiency, and cross-polarization discrimination less than 20 dB.

From the existing reports, although the microstrip line and the substrate integrated waveguide have advantages in antenna design, the contradiction between the microstrip line and the substrate integrated waveguide is not well solved, and either the microstrip line structure or the substrate integrated waveguide structure is completely adopted in design. The problems of loss, dual-polarization feed network design, dual-polarization antenna unit design, bandwidth, planarization and the like are difficult to meet at the same time.

Disclosure of Invention

The invention aims to solve the technical problem of providing the +/-45-degree dual-polarized millimeter wave array antenna which has high cross polarization discrimination, high aperture efficiency, low profile and easy processing.

The invention adopts the following technical scheme:

the improvement of a +/-45-degree dual-polarized millimeter wave array antenna is as follows: the substrate integrated waveguide cavity comprises a first metal layer, a first dielectric layer, a second metal layer, a bonding layer, a third metal layer, a second dielectric layer and a fourth metal layer which are sequentially stacked from bottom to top, wherein a lower metal array of a substrate integrated waveguide cavity is etched on the first metal layer, N cascaded feed networks and M power dividers are arranged, N is an even number larger than or equal to 4, M is a natural number larger than or equal to 2, the two cascaded feed networks are connected together through the power dividers, the substrate integrated waveguide cavity adopts an angular feed and square structure with two ports, signals respectively flow in from the two cascaded feed networks on two sides of the substrate integrated waveguide cavity through the two ports, a substrate integrated waveguide cavity metalized through hole, a cascaded feed network grounding patch metalized through hole and a power divider grounding patch metalized through hole are arranged in the first dielectric layer, the second metal layer and the third metal layer are floor layers, and the substrate integrated waveguide cavity array position is opposite to that of the substrate integrated waveguide cavity array, The array of the crossed cross slots with the same quantity, and the direction of each crossed cross slot is consistent with the direction of the diagonal line of the corresponding substrate integrated waveguide cavity, the substrate integrated waveguide cavity excites the crossed cross slots, the second metal layer and the third metal layer are bonded into a whole by the bonding layer, the array of the microstrip radiation patches with the same quantity and the position opposite to the crossed cross slot array is etched on the fourth metal layer, the direction of the microstrip radiation patches is consistent with the direction of the corresponding crossed cross slots, and the microstrip radiation patches generate dual-polarization radiation under the excitation of the crossed cross slots.

Furthermore, the cascade feed network is composed of microstrip lines, and a grounding patch is arranged at the bent part of the microstrip lines.

Furthermore, the power divider is composed of microstrip lines, two microstrip arms of the power divider are respectively connected with a cascade feed network, and a grounding patch is arranged between the two microstrip arms.

Furthermore, the substrate integrated waveguide cavity is realized by a square metallized through hole, the substrate integrated waveguide cavity also comprises a microstrip line, and two ports of the excitation substrate integrated waveguide cavity can respectively generate TE in the cavity₁₂₀And TE₂₁₀A mode electric field.

Furthermore, four micro-strip radiation patches etched on the fourth metal layer have quarter-circle cut angles respectively and are connected through the cross micro-strips.

Further, the array antenna comprises 2 × 8 antenna elements including a substrate integrated waveguide cavity, the center frequency of which is 28 GHz.

Further, the first dielectric layer is RO4003C, the dielectric constant is 3.55, the loss tangent is 0.0027, and the thickness is 0.305 mm; the second medium layer is also RO4003C, and the thickness is 0.508 mm; the adhesive layer is RO4450F, the thickness is 0.2mm, the dielectric constant is 3.52, and the loss tangent is 0.004; the first, second, third and fourth metal layers are all metal copper clad layers, and the thicknesses are all 0.5 ounce; the cross section height of the whole array antenna is 0.076 free space wavelengths, and the size of a substrate integrated waveguide cavity is 5.4 mm multiplied by 5.4 mm; the length and the width of the crossed cross gap are respectively 2.84 mm and 0.3 mm; the width of the microstrip radiation patch is 2.19 mm, the radius of a quarter of a circle corner cut of the microstrip radiation patch is 1.46 mm, the width of a gap between the microstrip radiation patch and the patch is 0.45mm, and the width of the cross-shaped thin microstrip is 0.17 mm.

The invention has the beneficial effects that:

the +/-45-degree dual-polarized millimeter wave array antenna disclosed by the invention adopts a hybrid design of a micro-strip and a substrate integrated waveguide, and a dual-polarized array antenna with a feed network is designed in a limited space. The substrate integrated waveguide cavity is fed in an angle feeding mode, and good port isolation and cross polarization discrimination are obtained. The use of quarter-circle corner cut patches increases the operating bandwidth of the antenna. The +/-45-degree dual-polarized millimeter wave array antenna disclosed by the invention has the advantages that the relative impedance bandwidth can reach 13.6%, the 2dB gain bandwidth can reach 6%, the port isolation is greater than 20 dB in the whole impedance bandwidth, and the cross polarization discrimination rate is 25 dB. Compared with the reported +/-45-degree dual-polarized millimeter wave planar array, the array antenna has the advantages of small size, high aperture efficiency, high cross polarization discrimination rate and the like. On the premise of simple structure, extremely low section and high integration level, the integrated design of the feed network and the array antenna can be realized simultaneously, and the antenna has better antenna performance.

Drawings

Fig. 1 is a schematic structural diagram of an array antenna disclosed in embodiment 1 of the present invention;

fig. 2 is a laminated view of the array antenna disclosed in embodiment 1 of the present invention;

fig. 3 is a schematic diagram of a cascaded feed network in the array antenna disclosed in embodiment 1 of the present invention;

fig. 4 is a schematic diagram of a power divider in the array antenna disclosed in embodiment 1 of the present invention;

fig. 5 is a schematic diagram of a substrate integrated waveguide cavity in the array antenna disclosed in embodiment 1 of the present invention;

fig. 6 is a schematic diagram of a cross-coupling slot etched in a floor layer of the array antenna disclosed in embodiment 1 of the present invention;

fig. 7 is a schematic diagram of a microstrip radiating patch in the array antenna disclosed in embodiment 1 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Embodiment 1, as shown in fig. 1-2, this embodiment discloses a ± 45 ° dual-polarized millimeter wave array antenna, which includes a first metal layer 11, a first dielectric layer 12, a second metal layer 13, a bonding layer 14, a third metal layer 15, a second dielectric layer 16, and a fourth metal layer 17 that are sequentially stacked from bottom to top, a lower metal 23 array of a substrate integrated waveguide cavity, 4 cascaded feed networks, and 2 power dividers are etched on the first metal layer, and the two cascaded feed networks are connected together by the power divider, as shown in fig. 5, the substrate integrated waveguide cavity 21 adopts an angular feed structure and is a square structure with two ports 25 and 26, which is beneficial to increasing the isolation between the ports and reducing cross polarization, and is also beneficial to miniaturization and convenient feeding of the antenna. Signals respectively flow in from the two cascaded feed networks on the two sides of the feed network through the two ports, and a substrate integrated waveguide cavity metalized through hole 22, a cascaded feed network grounding patch metalized through hole 513 and a power divider grounding patch metalized through hole 66 are arranged in the first dielectric layer to adjust the impedance matching of the feed network and the power divider. The second metal layer and the third metal layer are floor layers 31, as shown in fig. 6, arrays of cross slots 32 and 33 with the same number and opposite to the array of the substrate integrated waveguide cavity are etched, the direction of each cross slot is consistent with the direction of the diagonal of the corresponding substrate integrated waveguide cavity, the substrate integrated waveguide cavity excites the cross slots, the second metal layer and the third metal layer are bonded into a whole by the bonding layer, microstrip radiation patch arrays 41 with the same number and opposite to the array of the cross slots are etched on the fourth metal layer, the directions of the microstrip radiation patches are consistent with the directions of the corresponding cross slots, and the microstrip radiation patches are excited by the cross slots to generate dual-polarization radiation.

In dual-polarized array antenna design, the design of the feed network is often difficult and complicated due to space constraints. The feed network designed in this embodiment is a cascaded feed network, as shown in fig. 3, the cascaded feed network is composed of microstrip lines 512, and a ground patch 511 is disposed at a bend of the microstrip lines to reduce return loss and parasitic effect. By adjusting the width of the three 510 quarter-wavelength microstrip lines, a better matching effect can be achieved.

As shown in fig. 4, the power divider is used to transfer energy to each cascaded feed network, and is composed of microstrip lines, two microstrip arms of the power divider are respectively connected to one cascaded feed network, and a ground patch 64 is disposed between the two microstrip arms to reduce return loss.

The substrate integrated waveguide cavity is realized by a square metallized through hole, the substrate integrated waveguide cavity also comprises a microstrip line 24 for impedance matching, and two ports of the excitation substrate integrated waveguide cavity can respectively generate in the cavityTE₁₂₀And TE₂₁₀A mode electric field.

As shown in fig. 7, the four microstrip radiating patches etched on the fourth metal layer have quarter-circle cut corners and are connected by the cross-shaped thin microstrip 42. The design can increase the sensitivity of the antenna, facilitate the adjustment of impedance matching and expand the impedance bandwidth.

The array antenna contains 2 x 8 antenna elements containing a substrate integrated waveguide cavity with a center frequency of 28 GHz, for which full-wave electromagnetic simulations were performed in HFSS.

The first dielectric layer is RO4003C, the dielectric constant is 3.55, the loss tangent is 0.0027, and the thickness is 0.305 mm; the second medium layer is also RO4003C, and the thickness is 0.508 mm; the adhesive layer is RO4450F, the thickness is 0.2mm, the dielectric constant is 3.52, and the loss tangent is 0.004; the first, second, third and fourth metal layers are all metal copper clad layers, and the thicknesses are all 0.5 ounce; the cross section height of the whole array antenna is 0.076 free space wavelengths, and the size of a substrate integrated waveguide cavity is 5.4 mm multiplied by 5.4 mm; the length and the width of the crossed cross gap are respectively 2.84 mm and 0.3 mm; the width of the microstrip radiation patch is 2.19 mm, the radius of a quarter of a circle corner cut of the microstrip radiation patch is 1.46 mm, the width of a gap between the microstrip radiation patch and the patch is 0.45mm, and the width of the cross-shaped thin microstrip is 0.17 mm.

The embodiment discloses a microwave millimeter wave planar array antenna which can realize +/-45-degree dual polarization and has high cross polarization discrimination, high aperture efficiency, low profile, easiness in processing and low cost. The +/-45-degree dual-polarized array antenna adopts a cross-coupling slot to excite a microstrip antenna unit. Etching cross-coupling slot on a support diagonal TE₁₂₀And TE₂₁₀And the substrate of the mode is integrated on the waveguide structure cavity. Due to TE₁₂₀And TE₂₁₀Orthogonality of the modes, with the antenna having high port isolation and low cross-polarization. Meanwhile, the diagonal excitation is adopted, so that the miniaturization of the antenna and the design of a feed network are facilitated. The impedance bandwidth of the antenna is improved by connecting four microstrip patches together by a crossed metal strip. Such an array antenna has a level of element cross-polarization higher than 32 dB. After the feed network is added, the impedance of the antenna arrayThe bandwidth resistance can reach 13.6%. The array antenna adopts a cascade feed mode. In order to reduce the strong parasitic effect at the discontinuity of the microstrip line when the microstrip line works in a consistent high frequency, a grounding patch is inserted at the bending part of the microstrip line. The embodiment is suitable for the field of microwave and millimeter waves, and solves the technical difficulty of realizing +/-45-degree dual polarization in the design of high-frequency antennas.

Simulation results of the antenna unit show that the isolation between the two ports is 28 dB at the central frequency, the cross polarization discrimination is 32 dB, the working bandwidth is 27.2 GHz-28.8 GHz, and the gain value in the range is 6.2 dBi-7.2 dBi. The simulation result after the feed network is added shows that the impedance bandwidth of the antenna array is 13.6%, the 2dB gain bandwidth is 6%, the center frequency gain is 16.7 dBi, and the cross polarization discrimination is 25 dB.