Beam reconfigurable slot array antenna of SIW (Substrate Integrated Wave) structure similar to sugarcoated haws on stick

Abstract

The invention provides a beam reconfigurable slot array antenna of a SIW structure similar to a shape of sugarcoated haws on stick. The beam reconfigurable slot array antenna comprises a dielectric substrate, a metal patch and a metal floor, the metal patch comprises a feed patch, a rectangular radiation patch and a fan-shaped branch knot which are spliced, a plurality of rectangular bulges are arranged on the long edge of the rectangular radiation patch, and a SIW cavity structure similar to the shape of sugarcoated haws on sticks is arranged between the rectangular radiation patch and the metal floor; a plurality of first radiation slots are etched on the rectangular radiation patch, a second radiation slot is etched between the adjacent first radiation slots, and a PIN diode and a blocking capacitor are loaded at two ends of each second radiation slot respectively. The feed patch and the fan-shaped branch knot are used for realizing impedance matching, the working bandwidth of the antenna under different wave beam pointing directions is expanded, the SIW cavity structure similar to the shape of sugarcoated haws on stick provides an additional current path, and it is ensured that current can normally flow along the second radiation slots etched among the first radiation slots which are arranged at intervals, so that the service life of the antenna is prolonged, and the service life of the antenna is prolonged. Therefore, the pointing of the single beam of the antenna is accurately regulated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas, and relates to a reconfigurable antenna, in particular to a beam reconfigurable slot array antenna with a sugar-cane type SIW structure, which can be applied to fields such as satellite communication, 5G / 6G mobile communication, etc. BACKGROUND

[0002] An antenna is an important component of a wireless communication system. In today's wireless communication field, with the popularization of 5G technology and the rise of 6G research, higher requirements are put forward for the performance of the antenna. Due to the single function, poor flexibility and other shortcomings of the traditional fixed beam antenna, its limitations are increasingly highlighted, and the reconfigurable antenna technology emerges as the times require. The reconfigurable antenna technology is a kind of technology that can dynamically adjust the performance of the antenna according to the needs by changing the structure, radiation direction or other characteristics of the antenna, so as to meet the diversified communication needs, and is one of the key technologies in future wireless communication systems.

[0003] The basic structure of the substrate integrated waveguide (SIW) beam reconfigurable antenna mainly consists of a SIW cavity, a radiation unit, a reconfigurable part and a feeding structure. The SIW cavity is the core part, which is composed of a dielectric layer between the upper and lower metal layers and metal through holes on both sides, and has the advantages of low loss and high Q value. A slot, a gap or a patch and other radiation units are usually arranged above the SIW structure, which are used to realize electromagnetic wave radiation, and the position, number and shape of the radiation units directly affect the beam direction and radiation performance. In order to realize the dynamic adjustment of the beam, the reconfigurable part such as PIN diode, MEMS switch, liquid crystal material or varactor diode is introduced into the antenna structure, which is used to switch or adjust the state of the radiation unit, and through the control of the slot switch or the adjustment of the phase distribution and the feeding path, the flexible change of the beam direction is realized. In terms of the feeding structure, microstrip line, coaxial probe or coplanar waveguide (CPW) mode is usually used for feeding, and some designs also integrate SIW power dividers or phase shifters to support the needs of multi-beam or dynamic beam control. This kind of antenna combines the electrical performance of waveguide and the process advantage of planar circuit, and is suitable for high-performance and low-cost beam reconfigurable antenna system.

[0004] For example, the patent document with application publication number CN114628918A discloses a beam reconfigurable slot array antenna based on PIN diode loading, which is composed of a first metal layer, a dielectric substrate, and a second metal layer from top to bottom. Eight identical rectangular radiation slots are arranged on the surface of the first metal layer, and a PIN diode is loaded at the center of each radiation slot to control the state of the radiation slot. The dielectric substrate edge is uniformly distributed with cylindrical metal connecting rods connecting the first metal layer and the second metal layer, forming a single-width open cavity structure. By setting eight PIN diodes in the on or off state respectively, different radiation beams can be obtained, with a beam pointing direction of -45° to +45°. The invention realizes flexible beam control and can meet the demand of multi-beam base station for beam scanning, but it has the disadvantage that the working bandwidth under different beam pointing directions cannot completely cover the working frequency points, affecting the frequency coverage capability and consistency of system performance of the antenna in the full beam range. At the same time, the radiation characteristic of the invention is symmetric double beam, which means that it will also produce the opposite direction of the non-desired beam in addition to the desired beam direction, causing large gain fluctuation of the antenna under different beam pointing directions. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art and provide a kind of sugar-cane type SIW structure's beam reconfigurable slot array antenna, to solve the technical problems of the prior art that the working bandwidth under different beam pointing directions cannot completely cover the working frequency points, and the gain fluctuation caused by symmetric double beam.

[0006] To achieve the above purpose, the technical scheme adopted by the present application includes a dielectric substrate 1 and metal patches 2 and metal ground plates 3 printed on its upper and lower surfaces. The metal patch 2 includes a feed patch 22 composed of rectangular and trapezoidal patches, a rectangular radiation patch 21, and a fan-shaped branch 23 connected in sequence, the rectangular radiation patch 21 is provided with a plurality of rectangular protrusions on the long side, and a plurality of first metallized through holes 4 connected with the metal ground plate 3 are arranged along the edges of the two long sides, forming a sugar-cane type SIW cavity structure. The rectangular radiation patch 21 is etched with a plurality of first radiation slots 5 at the length direction, and a dumbbell-shaped second radiation slot 6 is etched between adjacent first radiation slots 5, and a PIN diode 7 and a DC blocking capacitor 8 are loaded at both ends of the second radiation slot 6. By controlling the on and off state of the PIN diode, the equivalent distance between adjacent radiation slots is dynamically adjusted, and the control of the antenna beam pointing direction is realized.

[0007] As an optimization, the rectangular radiation patch 21 is etched with a plurality of first radiation slots 5 at the length direction, and a dumbbell-shaped second radiation slot 6 is etched between adjacent first radiation slots 5, and a PIN diode 7 and a DC blocking capacitor 8 are loaded at both ends of the second radiation slot 6. By controlling the on and off state of the PIN diode, the equivalent distance between adjacent radiation slots is dynamically adjusted, and the control of the antenna beam pointing direction is realized.

[0008] As an optimization, the rectangular radiation patch 21, the multiple first metallized through holes 4 arranged equidistantly along the two long side edges and connected with the metal floor 3.

[0009] As an optimization, the rectangular radiation patch 21, the multiple first radiation slots 5 etched equidistantly along the length direction.

[0010] As an optimization, the fan-shaped branch 23, the center of which is located on the line connecting the midpoints of the two short sides of the rectangular radiation patch 21, and is connected with the metal floor 3 through one or more second metallized through holes 9.

[0011] As an optimization, the fan-shaped branch 23, the second metallized through holes 9 connected with the metal floor 3 are three and are in a triangular distribution.

[0012] As an optimization, the second radiation slot 6, the center of which is located on the line connecting the multiple first radiation slots 5.

[0013] As an optimization, the second radiation slot 6, is located on the line connecting the midpoints of the protruding pairs formed by the rectangular protrusions on the two long sides of the rectangular radiation patch 21.

[0014] As an optimization, the PIN diode 7 and the DC blocking capacitor 8, are symmetrically distributed at the two ends of the second radiation slot 6.

[0015] Compared with the prior art, the present application has the following advantages:

[0016] 1. The two ends of the rectangular radiation patch are respectively spliced with a feed patch composed of a rectangular patch and a trapezoidal patch and a fan-shaped branch with a second metallized via hole, the trapezoidal tapered feed line effectively avoids the problem of strong reflection caused by impedance mutation, reduces the energy loss at the feed, and the fan-shaped branch with the second metallized via hole forms a broadband impedance matching network as a whole. The working bandwidth of the antenna under different beam directions is expanded, and simulation results show that the application can cover the 35GHz working frequency point under different beam directions.

[0017] 2. The present application etches a transverse second radiation slot between the first radiation slots, which is equivalent to introducing a certain phase shift, which helps to realize a single beam and helps to control the direction of the antenna radiation beam. In addition, multiple rectangular protrusions are arranged on the long side of the rectangular radiation patch, and multiple first metallized through holes connected with the metal floor are arranged along the two long side edges, forming a sugar-cane type SIW cavity structure, providing an additional current path to ensure that the current can flow normally along the second radiation slot, ensuring the stability of the antenna gain and avoiding the influence of gain fluctuation on the performance of the communication system. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the overall structure of the present application.

[0019] Figure 2 Figure 2 is a partial enlarged view of the position relationship between the second radiation slot, the PIN diode and the DC blocking capacitor on the rectangular radiation patch of the present application.

[0020] Figure 3 is a simulation result diagram of the reflection coefficient of the present application and the prior art.

[0021] Figure 4 is a radiation pattern in the yoz plane of the present application and the prior art. DETAILED DESCRIPTION

[0022] The present application will be further described in detail below in conjunction with the drawings and specific embodiments:

[0023] Reference Figure 1 and Figure 2 The present application includes a dielectric substrate 1 and metal patches 2 and metal ground plate 3 printed on the upper and lower surfaces thereof; the dielectric substrate 1 adopts Rogers 5880 material with a length of 130.32 mm, a width of 20 mm, a thickness of 0.508 mm, a dielectric constant of 2.2 and a loss tangent of 0.0009.

[0024] The metal patch 2 includes a rectangular radiation patch 21 provided with a plurality of rectangular protrusions on the long side, the rectangular part of which has a length of 110.32 mm and a width of 8.6 mm, the rectangular protruding part of which extends outward by a length W_int = 2 mm and a width L_int = 2.3 mm, and the distance between adjacent rectangular protruding parts is dx = 3.93 mm. The rectangular radiation patch 21 is spliced at one end with a feed patch 22 with a rectangular starting end and a trapezoidal end, and at the other end with a fan-shaped branch 23; the rectangular part of the feed patch 22 has a length of 6.9 mm and a width of 1.43 mm, the trapezoidal part has a short side length of 1.43 mm and a long side length of 2 mm, and the length is 3.1 mm; the fan-shaped branch 23 has a complete fan-shaped radius length of 5.1 mm, a fan-shaped radius length covered by the rectangular radiation patch 21 of 1.6 mm, and an arc of 38°. The end of the feed patch 22 adopts a trapezoidal structure with gradually changing width, so that the characteristic impedance of the transmission line is smoothly transitioned along the electromagnetic wave propagation direction, thereby establishing a continuous impedance matching channel between the feed line and the rectangular radiation patch. Compared with the traditional step-type feed structure, the trapezoidal tapered feed line effectively avoids the problem of strong reflection caused by impedance mutation, reduces the energy loss at the feed point, realizes wide-band and high-efficiency impedance matching, and is used to expand the working bandwidth.

[0025] The fan-shaped branch 23 has its center located on the line connecting the midpoints of the two short sides of the rectangular radiation patch 21 and is connected to the metal ground plate 3 through three second metalized vias 9. The second metalized vias 9 are located inside the fan-shaped branch 24 and are arranged in a triangular shape. The leftmost via is located on the line connecting the midpoints of a group of short sides of the dielectric substrate 1, and the center of the leftmost via is spaced apart from the rightmost edge of the rectangular radiation patch 21 by 2 mm. The right two vias are symmetric about the line connecting the centers of a group of short sides of the dielectric substrate 1, and the centers of the right two vias are spaced apart from the line by 0.4 mm and spaced apart from the rightmost edge of the rectangular radiation patch 21 by 3 mm. The fan-shaped open-circuit branch is connected to the edge of the antenna radiation patch and uses the quarter-wavelength impedance transformation characteristic to make the current at the root of the fan-shaped branch present a short-circuit state, thereby achieving the effect of stopband suppression. Meanwhile, the end of the branch is connected to the ground through a short-circuit hole, which introduces an additional inductive component at high frequencies and helps to compensate for the redundant capacitive component in the reactance of the rectangular radiation patch, thereby forming a broadband impedance matching network and further expanding the operating bandwidth.

[0026] The rectangular radiation patch 21 is etched with 25 first radiation slots 5 arranged alternately. Adjacent first radiation slots 5 are linearly arranged at an interval dx = 3.93 mm, and the length of each first radiation slot 5 is L1 = 2.8 mm. The center of each first radiation slot 5 is spaced apart from the line connecting the midpoints of the two short sides of the rectangular radiation patch 21 by X3 = 0.9 mm.

[0027] The rectangular radiation patch 21 is provided with a plurality of first metalized vias 4 arranged at intervals along the edges of the two long sides and connected to the metal ground plate 3. The first metalized vias 4 have a diameter of 0.4 mm, and the distance between adjacent vias is 0.65 mm. The first metalized vias 4 connect the rectangular radiation patch 21 and the metal ground plate 3 to form a sugar-cane-shaped SIW cavity structure. In the SIW structure, the propagation of electromagnetic waves depends on the waveguide structure formed by the metalized vias and the upper and lower metal layers. Etching second radiation slots between two first radiation slots will disturb the continuity of the current to some extent, thereby destroying the electromagnetic wave propagation mode of the SIW structure. The sugar-cane-shaped SIW structure can provide an additional current path to ensure that the current can flow to the subsequent slots, thereby ensuring the stability of the antenna gain and avoiding the influence of gain fluctuation on the performance of the communication system.

[0028] The first radiation slots 5 are etched with periodically arranged dumbbell-shaped second radiation slots 6 between adjacent slots. The center of each second radiation slot 6 is located on the line connecting a plurality of first radiation slots 5. The length of the middle rectangle of each second radiation slot 6 is 0.82 mm, and the width is 0.3 mm. The length of the two side rectangles is 0.8 mm, and the width is 0.9 mm. The total length X1 = 2.42 mm. The beam direction is determined by the relative phase between the antenna radiation slots. Etching the second radiation slots 6 is equivalent to introducing a certain phase shift between the first radiation slots, which helps to realize a single directional beam and helps to control the direction.

[0029] The PIN diode 7 has a rectangular length of 0.35 mm and a width of 0.4 mm, and the direct-current blocking capacitor 8 has a rectangular length of 0.3 mm and a width of 0.3 mm and is symmetrically distributed at both ends of the transverse radiation slot 6.

[0030] By controlling the on and off states of the PIN diode, the equivalent spacing between adjacent radiation slots is dynamically adjusted, thereby realizing the regulation of the antenna beam pointing direction, and the specific method is as follows:

[0031] When the PIN diode is fully on, it is in state 11, when the upper part of the PIN diode is on and the lower part of the PIN diode is off, it is in state 10, when the upper part of the PIN diode is off and the lower part of the PIN diode is on, it is in state 01, and when the PIN diode is fully off, it is in state 00.

[0032] The technical effects of the present application are further described below in combination with simulation experiments:

[0033] 1. Simulation conditions and contents:

[0034] The simulation is performed by using a commercial simulation software HFSS_19.2.

[0035] 1.1 The reflection coefficient in the embodiment 1 of the present application is simulated, and the result is shown in Fig. 3(b).

[0036] 1.2 The radiation pattern of the yoz plane in the embodiment 1 of the present application is simulated, and the result is shown in Fig. 4(b).

[0037] 2. Analysis of simulation results:

[0038] Referring to Fig. 3, the horizontal axis is the working frequency, with the unit of GHz, and the vertical axis is the reflection coefficient, with the unit of dB.

[0039] Fig. 3(a) is the simulation result of the reflection coefficient of the prior art, and the standard is S11<-10dB. When the beam pointing direction is 0°, the working bandwidth is 8.6% (5.55GHz-6.05GHz), covering the working frequency point of 5.8Ghz. When the beam pointing direction is 15°, the working bandwidth is 7.1% (5.57GHz-5.98GHz), covering the working frequency point of 5.8Ghz. When the beam pointing direction is 30°, the working bandwidth is 7.2% (5.58GHz-6GHz), covering the working frequency point of 5.8Ghz. When the beam pointing direction is 0°, the working bandwidth is 1.9% (5.89GHz-6GHz), not covering the working frequency point of 5.8Ghz.

[0040] Fig. 3(b) is a reflection coefficient simulation result of the present application, the -10dB operating bandwidth of the antenna in the full-on 11 state of the PIN diode is 13% (33.45GHz-38GHz); the -10dB operating bandwidth in the state that the upper part of the PIN diode is on and the lower part is off is 10.6% (33.51GHz-37.22GHz); the -10dB operating bandwidth in the state that the upper part of the PIN diode is off and the lower part is on is 14.6% (32.89GHz-38GHz); and the -10dB operating bandwidth in the full-off 00 state of the PIN diode is 7.09% (33.57GHz-36.05GHz).

[0041] As can be seen from Fig. 3, the operating bandwidth of the present application is wide in the four working states, and can cover the operating frequency points. The operating bandwidth of the prior art in the four working states cannot completely cover the operating frequency points, which affects the frequency coverage ability of the antenna in the full beam range and the consistency of the system performance.

[0042] Referring to Fig. 4, the horizontal axis is the scanning angle, in degrees, and the vertical axis is the antenna gain, in dBi.

[0043] Fig. 4(a) is a radiation direction simulation result of the prior art, the antenna gain is 11.6dBi at 0° pointing, 7.3dBi at 15° pointing, 9.1dBi at 30° pointing, and 9.0dBi at 45° pointing. The prior art realizes beam reconfiguration from -45° to 45°, but it is a symmetrical double beam except for the 0° pointing beam, which means that it will also produce an undesired beam in the opposite direction in addition to the desired beam direction, resulting in large fluctuations in the antenna gain in different beam pointing states, with a maximum gain difference of 4.3dB.

[0044] Fig. 4(b) is a radiation direction simulation result of the present application, at the operating frequency point of 35GHz, the beam points to 45° with a gain of 14.06dBi in the full-on 11 state of the PIN diode; the beam points to 49° with a gain of 15.31dBi in the state that the upper part of the PIN diode is on and the lower part is off; the beam points to 51° with a gain of 15.59dBi in the state that the upper part of the PIN diode is off and the lower part is on; and the beam points to 60° with a gain of 13.11dBi in the full-off 00 state of the PIN diode.

[0045] As can be seen from FIG. 4, the application is a single beam in four working states, realizes the pointing reconfiguration of the single beam, and the antenna gain fluctuation is small in different beam pointing states, and the maximum gain difference is 2.2 dB. The antenna gain fluctuation is large in different beam pointing states in the prior art, and the maximum gain difference is 4.3 dB, and the unstable gain output will cause the communication quality to decrease.

[0046] The above is one specific embodiment of the application, which does not constitute any limitation to the application. Obviously, for those skilled in the art, after understanding the content and principle of the application, various modifications and changes in form and details can be made without departing from the principle and structure of the application. However, these modifications and changes based on the idea of the application are still within the scope of the claims and protection of the application.

Claims

1. A beam-reconfigurable slot array antenna with a candied hawthorn-like SIW structure, comprising a dielectric substrate (1) and metal patches (2) printed on its upper and lower surfaces, and a metal ground plane (3); characterized in that, The metal patch (2) includes a feed patch (22) composed of rectangular and trapezoidal patches, a rectangular radiating patch (21) and a fan-shaped branch (23) assembled sequentially. The rectangular radiating patch (21) has multiple rectangular protrusions on its long side and multiple first metallized through holes (4) connected to the metal ground plate (3) along its two long edges, forming a candied hawthorn-shaped SIW cavity structure. The rectangular radiating patch (21) has multiple alternating first radiating slots (5) etched along its length. Dumbbell-shaped second radiating slots (6) are etched between adjacent first radiating slots (5). Each end of the second radiating slot (6) is loaded with a PIN diode (7) and a DC blocking capacitor (8). By controlling the conduction and cutoff states of the PIN diodes, the equivalent spacing between adjacent radiating slots is dynamically adjusted, thereby realizing the control of the antenna beam pointing.

2. The antenna according to claim 1, characterized in that, The rectangular radiating patch (21) has multiple alternating first radiating slots (5) etched on it, located on one side of the line connecting the midpoints of the two short sides of the rectangular radiating patch (21).

3. The antenna according to claim 1, characterized in that, The rectangular radiating patch (21) has multiple first metallized through holes (4) connected to the metal floor (3) arranged at equal intervals along its two long edges.

4. The antenna according to claim 1, characterized in that, The rectangular radiating patch (21) has multiple alternating first radiating slots (5) etched along its length direction, arranged at equal intervals.

5. The antenna according to claim 1, characterized in that, The fan-shaped branch (23) has its center located on the line connecting the midpoints of the two short sides of the rectangular radiating patch (21), and is connected to the metal floor (3) through one or more second metallized through holes (9).

6. The antenna according to claim 5, characterized in that, The fan-shaped branch (23) has three second metallized through holes (9) connected to the metal floor (3), and they are distributed in a triangular pattern.

7. The antenna according to claim 1, characterized in that, The center of the second radiation slit (6) is located on the line connecting the plurality of first radiation slits (5).

8. The antenna according to claim 1, characterized in that, The second radiation slit (6) is located on the line connecting the midpoints of the pairs of protrusions formed by the rectangular protrusions on the two long sides of the rectangular radiation patch (21).

9. The antenna according to claim 1, characterized in that, The PIN diode (7) and DC blocking capacitor (8) are symmetrically distributed at both ends of the second radiation gap (6).

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