阅读说明：本技术 一种具有宽频带双波束的基片集成波导背腔缝隙天线 (Substrate integrated waveguide back cavity slot antenna with broadband dual-beam ) 是由 李霜 吴为军 温定娥 谭辉 赵逸夫 于 2021-06-24 设计创作，主要内容包括：本发明公开了一种具有宽频带双波束的基片集成波导背腔缝隙天线,该天线上层的金属表面包括：W型缝隙、接地功率共面馈电结构、微带馈电线；W型缝隙关于天线中心呈镜像对称,W型缝隙作为辐射单元,用于在一定宽度的频带范围内产生双波束辐射,且两个波束关于天线中心也呈镜像对称；接地功率共面馈电结构设置在W型缝隙的一侧,用于实现宽阻抗带宽特性；微带馈电线设置在接地功率共面馈电结构的一侧,且微带馈电线被加载在接地功率共面馈电结构内导体的末端；下层、中间层、上层的边缘还设置有一圈等间距排列的金属化通孔。本发明实现了宽频带双波束,具有较宽的带宽,且结构简单,大大提高了基片集成波导的实用性。(The invention discloses a substrate integrated waveguide back cavity slot antenna with broadband dual-beam, the metal surface of the upper layer of the antenna comprises: the device comprises a W-shaped gap, a grounding power coplanar feed structure and a microstrip feed line; the W-shaped slot is in mirror symmetry with respect to the center of the antenna, and serves as a radiation unit for generating dual-beam radiation in a frequency band range with a certain width, and the two beams are also in mirror symmetry with respect to the center of the antenna; the grounding power coplanar feed structure is arranged on one side of the W-shaped gap and used for realizing the wide impedance bandwidth characteristic; the microstrip feed line is arranged on one side of the grounding power coplanar feed structure and is loaded at the tail end of the conductor in the grounding power coplanar feed structure; the edges of the lower layer, the middle layer and the upper layer are also provided with a circle of metalized through holes which are arranged at equal intervals. The invention realizes broadband dual-beam, has wider bandwidth and simple structure, and greatly improves the practicability of the substrate integrated waveguide.)

1. A substrate integrated waveguide back cavity slot antenna with broadband dual beams is characterized in that the antenna is based on a substrate integrated waveguide structure and comprises three layers: the lower layer (1) is a metal surface and is used as a grounding plate; the middle layer (2) is a dielectric plate; the upper layer (3) is a metal surface; wherein:

the metal surface of the upper layer includes: the power supply device comprises a W-shaped slot (4), a grounding power coplanar feed structure (5) and a microstrip feed line (6); the W-shaped slot (4) is in mirror symmetry with respect to the center of the antenna, the W-shaped slot (4) is used as a radiation unit and is used for generating dual-beam radiation in a frequency band range with a certain width, and the two beams are also in mirror symmetry with respect to the center of the antenna; the grounding power coplanar feed structure (5) is arranged on one side of the W-shaped gap (4) and is used for realizing the wide impedance bandwidth characteristic; the microstrip feed line (6) is arranged on one side of the grounding power coplanar feed structure (5), and the microstrip feed line (6) is loaded at the tail end of the conductor in the grounding power coplanar feed structure (5); the edges of the lower layer (1), the middle layer (2) and the upper layer (3) are also provided with a circle of metalized through holes (7) which are arranged at equal intervals.

2. The substrate integrated waveguide cavity-backed slot antenna with broadband dual beam according to claim 1, wherein the W-shaped slot (4) and the ground power coplanar feed structure (5) are etched on the upper metal surface, the ground power coplanar feed structure (5) is two L-shaped slots, and the two L-shaped slots are mirror symmetric with respect to the antenna center.

3. The substrate integrated waveguide cavity-backed slot antenna with broadband dual-beam according to claim 1, wherein the dielectric plate is a Rogers5880 plate.

4. The substrate integrated waveguide cavity-backed slot antenna with broadband dual-beam according to claim 3, wherein a Rogers5880 board with a dielectric constant of 2.2 and a thickness of 1.5mm is used as the dielectric board.

5. The substrate integrated waveguide cavity-backed slot antenna with broadband dual beam according to claim 2, characterized in that the width between two L-shaped slots of the ground power coplanar feeding structure (5) is the same as the width of the microstrip feed line (6).

6. The substrate integrated waveguide cavity-backed slot antenna with broadband dual beam according to claim 5, characterized in that the microstrip feed line (6) is 50 ohm.

7. The substrate integrated waveguide cavity-backed slot antenna with broadband dual-beam according to claim 1, wherein the dimensions of the W-shaped slot (4), the ground power coplanar feeding structure (5) and the microstrip feed line (6) are calculated to enable the W-shaped slot (4) to generate dual-beam radiation characteristics in a certain frequency band range, and the specific method is as follows:

w50 is the width of a 50 ohm microstrip feed line, and is directly calculated by a theoretical formula, and the specific numerical value is 4.6 mm;

the initial value of Linst is 0.25 times of the wavelength of the medium, corresponding to the central frequency of 14.2GHz, and the optimal value is 4 mm;

the length of the Linst1 is optimized and then is selected to be 5 mm;

setting dS to be 13mm by taking the central position of the cavity;

winst and winst1 are optimized values, the impedance matching characteristic is met under the condition of being as narrow as possible, and the requirement of processing precision is met, and 0.5mm is selected after optimization;

the L1 corresponds to a high-frequency point of 15GHz, the high-frequency point is selected to be 6mm after optimization, the L2 corresponds to a low-frequency point of 13.5GHz, and the low-frequency point is selected to be 9mm after optimization.

Technical Field

The invention relates to the technical field of electromagnetic compatibility and antennas, in particular to a substrate integrated waveguide back cavity slot antenna with broadband dual beams.

Background

Within the field of antennas, substrate integrated waveguide technology has been successfully utilized. The slot waveguide array antenna has the excellent characteristics of narrow main lobe width and the like, and is an important microwave antenna which can be widely applied to communication and radar systems. However, the metal waveguide has the disadvantages that the first waveguide is heavy, the second waveguide is expensive in manufacturing cost, the third waveguide is large in size, the problems of large processing error, difficulty in large-scale production and the like exist, the design concept of the traditional rectangular waveguide slot antenna is borrowed from the substrate integrated waveguide, the problems can be overcome, the slot antenna array can be designed, and finally the excellent performance of the traditional rectangular waveguide slot antenna can be obtained.

The dual-beam antenna means that electromagnetic waves radiated to the air by the antenna consist of two beams, and each beam covers a certain airspace, so that the requirement of covering two directions at the same time is met. Through the excellent coverage characteristic of the dual-beam antenna, fine control on coverage is achieved, various optimization difficulties caused by over-coverage and multiple signal overlapping are reduced, and the capacity is improved.

The design method of the substrate integrated waveguide back cavity slot antenna with the broadband dual-beam provided by the invention simultaneously realizes the broadband dual-beam and has a simple structure, the antenna has the characteristics similar to the traditional substrate integrated waveguide, and the dual-beam, the bandwidth is wide, the structure is simple, and the practicability of the substrate integrated waveguide is greatly improved.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a substrate integrated waveguide back cavity slot antenna with a broadband dual-beam aiming at the defects in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the invention provides a substrate integrated waveguide back cavity slot antenna with broadband dual-beam, which is based on a substrate integrated waveguide structure and comprises three layers: the lower layer is a metal surface and is used as a grounding plate; the middle layer is a dielectric plate; the upper layer is a metal surface; wherein:

the metal surface of the upper layer includes: the device comprises a W-shaped gap, a grounding power coplanar feed structure and a microstrip feed line; the W-shaped slot is in mirror symmetry with respect to the center of the antenna, and serves as a radiation unit for generating dual-beam radiation in a frequency band range with a certain width, and the two beams are also in mirror symmetry with respect to the center of the antenna; the grounding power coplanar feed structure is arranged on one side of the W-shaped gap and used for realizing the wide impedance bandwidth characteristic; the microstrip feed line is arranged on one side of the grounding power coplanar feed structure and is loaded at the tail end of the conductor in the grounding power coplanar feed structure; the edges of the lower layer, the middle layer and the upper layer are also provided with a circle of metalized through holes which are arranged at equal intervals.

Furthermore, the W-shaped slot and the grounding power coplanar feed structure are etched on the upper metal surface, the grounding power coplanar feed structure is two L-shaped slots, and the two L-shaped slots are in mirror symmetry with respect to the center of the antenna.

Further, the dielectric sheet of the present invention is a Rogers5880 sheet.

Furthermore, the dielectric plate of the invention adopts a Rogers5880 plate with the dielectric constant of 2.2 and the thickness of 1.5 mm.

Further, the width between the two L-shaped slots of the grounding power coplanar feeding structure of the invention is the same as that of the microstrip feed line,

further, the microstrip feed line of the present invention is 50 ohms.

Furthermore, the invention makes the W-shaped slot generate dual-beam radiation characteristic in a certain frequency band range by calculating the sizes of the W-shaped slot, the grounding power coplanar feeding structure and the microstrip feeding line, and the specific method is as follows:

w50 is the width of a 50 ohm microstrip feed line, and is directly calculated by a theoretical formula, and the specific numerical value is 4.6 mm;

the initial value of Linst is 0.25 times of the wavelength of the medium, corresponding to the central frequency of 14.2GHz, and the optimal value is 4 mm;

the length of the Linst1 is optimized and then is selected to be 5 mm;

setting dS to be 13mm by taking the central position of the cavity;

winst and winst1 are optimized values, the impedance matching characteristic is met under the condition of being as narrow as possible, and the requirement of processing precision is met, and 0.5mm is selected after optimization;

the L1 corresponds to a high-frequency point of 15GHz, the high-frequency point is selected to be 6mm after optimization, the L2 corresponds to a low-frequency point of 13.5GHz, and the low-frequency point is selected to be 9mm after optimization.

The invention has the following beneficial effects: the substrate integrated waveguide back cavity slot antenna with the broadband dual-beam is based on a substrate integrated waveguide structure, a W-shaped slot is formed in the upper surface by utilizing unique surface current distribution of the structure, dual-beam radiation characteristics are generated in a wide frequency band range, two beams are completely in mirror symmetry with respect to the center of the antenna, and the highest gain reaches 7.8 dBi. Meanwhile, a grounded coplanar waveguide structure is introduced into the cavity, and the mode in the cavity is excited by utilizing the two transverse grooves, so that the effect of widening an impedance frequency band is realized; the antenna has the characteristics of dual-beam radiation and better broadband characteristics, and is very suitable for the radio frequency front end of a modern wireless communication system.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic three-dimensional structure of an embodiment of the present invention;

FIG. 2 is a schematic plan view of an embodiment of the present invention;

FIG. 3 shows the simulation results of the antenna according to the embodiment of the present invention;

FIG. 4 is an antenna pattern of an embodiment of the present invention; (a) 13.4GHz, (b) 13.7GHz, (c) 14.1 GHz;

FIG. 5 is a graph of the antenna main beam direction gain results according to an embodiment of the present invention;

FIG. 6 is a current distribution diagram for an antenna of an embodiment of the present invention at 13.6 GHz;

FIG. 7 is a graph of reflection coefficient results for an antenna of an embodiment of the present invention as a function of parameters; (a) the values are linst change, (b) ds change, and (c) w1 change.

FIG. 8 is a graph of the results of the performance of the antenna as a function of parameters for an embodiment of the present invention, (a) is the reflection coefficient of the antenna as rot changes; (b) is the reflection coefficient of the antenna at the time of rot1 change; (c) is the directional diagram of the antenna when rot changes; (d) is the antenna pattern when rot1 changes.

Detailed Description

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

As shown in fig. 1-2, the substrate integrated waveguide cavity-backed slot antenna with broadband dual-beam according to the embodiment of the present invention is based on a substrate integrated waveguide structure, and includes three layers: the lower layer is a metal surface and is used as a grounding plate; the middle layer is a dielectric plate; the upper layer is a metal surface; wherein:

the metal surface of the upper layer includes: the device comprises a W-shaped gap, a grounding power coplanar feed structure and a microstrip feed line; the W-shaped slot is in mirror symmetry with respect to the center of the antenna, and serves as a radiation unit for generating dual-beam radiation in a frequency band range with a certain width, and the two beams are also in mirror symmetry with respect to the center of the antenna; the grounding power coplanar feed structure is arranged on one side of the W-shaped gap and used for realizing the wide impedance bandwidth characteristic; the microstrip feed line is arranged on one side of the grounding power coplanar feed structure and is loaded at the tail end of the conductor in the grounding power coplanar feed structure; the edges of the lower layer, the middle layer and the upper layer are also provided with a circle of metalized through holes which are arranged at equal intervals.

The W-shaped slot and the grounding power coplanar feed structure are etched on the upper metal surface, the grounding power coplanar feed structure is two L-shaped slots, and the two L-shaped slots are in mirror symmetry with respect to the center of the antenna.

By adopting the grounding coplanar waveguide feed technology, the bandwidth of the antenna is widened. Meanwhile, a gap is formed on the upper surface of the substrate integrated waveguide structure, and dual-beam radiation characteristics are generated in a frequency band range of 13.4GHz-14.1 GHz. Meanwhile, a grounded coplanar waveguide structure is introduced into the cavity of the antenna, and the mode in the cavity is excited by utilizing the two transverse grooves, so that the effect of widening the impedance frequency band is realized.

In another embodiment of the invention:

1. designing an antenna;

the antenna is composed of three parts as shown in fig. 1-2, the lower metal surface is used as the grounding plate, the middle dielectric plate of rogers5880, and the upper metal surface. The upper metal surface comprises a W-shaped slot forming radiation, a grounding power coplanar waveguide feed structure for realizing wide impedance bandwidth characteristics and a microstrip feed line for facilitating integration and measurement.

The radiating unit and the impedance matching structure are etched on the upper surface of the substrate integrated waveguide structure, a Rogers5880 plate with the dielectric constant of 2.2 and the thickness of 1.5mm is used as a dielectric plate, the radius and the distance of the metalized through holes can be calculated, and the minimum energy leakage is ensured.

In addition, for ease of measurement and ease of integration with the rest of the planar circuit, a 50 ohm microstrip feed line is loaded at the end of the conductor in the grounded coplanar waveguide feed structure, which has the same width as the 50 ohm feed line for smooth transition. And the width of the microstrip feed line is slightly smaller than the theoretical calculation value in order to realize better impedance matching and smaller energy leakage.

Fig. 3 gives the reflection coefficients of the mentioned antennas, fig. 4 gives the directivity patterns of the yoz plane of the antennas at 13.4GHz, 13.7GHz and 14.1GHz, and fig. 5 gives the gain results of the antennas in the main beam direction. It can be seen from the results that the operating band of the antenna is 13.4GHz-15GHz and the relative bandwidth reaches 11.2%, and that within the operating band the maximum gain of the main beam fluctuates in the range of 4.94dBi-7.8dBi, the antenna beam is pointed at phi 90 ° and theta ± 42 °.

In order to better improve the dual-beam characteristics of the slot antenna, the present invention gives explanations in terms of both slot structure and current distribution. The W-shaped gap is located in the center of the cavity, the gap structure is in mirror symmetry along the central axis, and as current flows around the center on the upper surface of the cavity, the two surfaces of the W-shaped gap cut the current in different directions, so that two different mirror image beams are generated. The current distribution results at 13.6GHz are shown in fig. 6, the current is mainly concentrated in the two lower vertexes and the two short-side slots of the W-shaped slot, the antenna flows to different directions, and thus, beams in two directions are generated.

2. Optimizing, simulating and analyzing parameters;

in order to better understand the effect of the shape parameters of the W-shaped slot on the dual-beam, and the influence of the position of the W-shaped slot and the grounded coplanar waveguide feed structure on the impedance bandwidth of the antenna, some main parameters are analyzed, and specific analysis results are shown below.

As can be seen from fig. 7-8, when the feed length linst is 3mm, the antenna only has a resonance point at high frequency, the resonance point at low frequency is gradually and completely excited with the increase of the length, and the impedance of the antenna is gradually mismatched when the length of linst is greater than 4.5 mm. When the slot is closer to the edge of the cavity than ds, the antenna does not get matched, and when ds is 13mm, the antenna exhibits good matching characteristics. When w1 is changed, the low-frequency resonance point and the matching condition of the antenna are basically unchanged, but the resonance point of the antenna at high frequency is gradually increased with the increase of w1, and the bandwidth of the antenna is widened.

As rot and rot1 increase, the operating bandwidth of the antenna gradually shifts to high frequencies, but the antenna achieves the best impedance matching results when rot and rot1 are equal to 60 °. At the same time, the pattern change also demonstrates that at 60 °, the antenna has a better pattern and gain results.

W50 is the width of a 50 ohm microstrip feed line, and is directly calculated by a theoretical formula, and the specific value is 4.6 mm;

linst has an initial value of 0.25 times the wavelength of the medium, corresponding to a center frequency of 14.2GHz, and an initial value of 3.61 mm. Subsequent optimization was 4 mm.

Linst1 is designed to excite the TE110 mode, and therefore has a length equal to about 3.61mm, but is typically longer than this length, so it is optimized to 5 mm.

The dS is set to 13mm, because the center of the chamber is assumed.

winst and winst1 are optimized values, have no obvious basis, and can meet impedance matching characteristics under the condition of being as narrow as possible, but can not be infinitely narrow, and also can meet the requirement of processing precision, so that the initial value is generally more biased to 0.5mm, and then the optimization is started.

L1 corresponds to the high frequency point of 15GHz with a theoretical initial value of 7mm, L2 corresponds to the low frequency point of 13.5GHz with a theoretical initial value of 7.7 mm. This length is now, after optimization, 6mm and 9mm respectively.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.