A compact broadband polarization reconfigurable antenna based on stepped dipole

Abstract

The present invention discloses a compact broadband polarization reconfigurable antenna based on a stepped dipole, comprising a dielectric substrate, an upper stepped half-dipole, a lower stepped half-dipole, an upper DC bias line, a lower DC bias line, a metal floor, a DC metal bias column, a coaxial feed line, an upper pentagonal feed patch, a lower pentagonal feed patch, an upper diode, a lower diode, and a choke inductor. Overall, the upper and lower patch structures are symmetrically distributed at 180°. Each elliptical radiation patch is truncated in the middle into an upper stepped half-dipole and a lower stepped half-dipole, the inner part is an upper stepped half-dipole, the outer part is a lower stepped half-dipole, and the lower stepped half-dipole is indented inwardly. Through the special shape design of the stepped dipole, the electrical length of the antenna is greatly reduced, and it has the characteristics of miniaturization; and the working bandwidth of the antenna is also expanded. The antenna has the characteristics of miniaturization and wide working frequency bandwidth.

Description

Technical Field

[0001] The invention relates to the technical field of antennas, and in particular to a compact broadband polarization reconfigurable antenna based on a stepped dipole and a design method thereof. Background Art

[0002] The rapid development of information technology has promoted the innovation of wireless communication technology. Modern wireless communication systems have put forward higher requirements for antennas, requiring high speed, wide bandwidth and strong anti-interference capabilities. These requirements have been proven to significantly improve the quality of communication links in applications in various fields. As the core of system performance, the performance of antennas is particularly important.

[0003] The structure and working state of traditional antenna design are usually fixed, which makes it difficult to meet the diverse needs of modern wireless systems. Some application scenarios require antennas to work in different polarization states and wide frequency bands to maximize transmission power and reduce multipath fading. However, fixed-structure antennas are difficult to meet these needs.

[0004] At the same time, antenna miniaturization has always been a research focus. Modern electronic devices require antennas to be as small as possible while maintaining high performance and meeting communication needs. In order to meet these challenges, miniaturized broadband polarization reconfigurable antennas have attracted much attention in recent years. This type of antenna can flexibly adjust its working state to adapt to different polarization and frequency band requirements, thereby improving performance while maintaining a compact size and meeting the stringent requirements of modern wireless communication systems.

[0005] From the published literature and patents, similar antennas that have been realized cannot meet the requirements of broadband performance, polarization reconfigurability and miniaturization. For example:

[0006] A Chinese invention patent (CN115458944B) proposes a miniaturized reconfigurable circularly polarized high-gain ring antenna based on a slow-wave transmission line. The slow-wave transmission line is formed by combining a circular ring patch with a periodically arranged fan-ring patch, thereby miniaturizing the antenna without destroying the original antenna mode. However, the antenna can only realize circular polarization reconfiguration and cannot realize linear polarization control.

[0007] The Chinese invention patent (CN116937143A) proposes a reconfigurable miniaturized AIS omnidirectional antenna, which adjusts the equivalent length of the current path by switching on and off the diode, and realizes the reconfiguration of the frequency, but does not realize the miniaturized design and polarization reconfiguration function.

[0008] The Chinese invention patent (CN114243279A) proposes a broadband multi-polarization reconfigurable antenna loaded with a double-layer metal sheet, which achieves the widening of the antenna frequency band by loading a disk structure, but does not achieve a miniaturized design.

[0009] In summary, the design of compact broadband polarization reconfigurable antennas has important research and application value. Summary of the invention

[0010] In order to overcome the shortcomings and deficiencies of the prior art, the present invention provides a compact broadband polarization reconfigurable antenna based on a stepped dipole. The present invention adopts the following technical solutions:

[0011] A compact broadband polarization reconfigurable antenna based on a stepped dipole, characterized in that it includes a dielectric substrate, an upper stepped half-dipole, a lower stepped half-dipole, an upper DC bias line, a lower DC bias line, a metal floor, a DC metal bias column, a coaxial feed line, an upper pentagonal feed patch, a lower pentagonal feed patch, an upper diode, a lower diode, and a choke inductor. The compact broadband polarization reconfigurable antenna based on a stepped dipole, the stepped half-dipole, the lower stepped half-dipole, the upper DC bias line, the lower DC bias line, the upper pentagonal feed patch, the lower pentagonal feed patch, the upper diode, the lower diode, and the choke inductor are symmetrically distributed at 180° as a whole. The main body shape of the upper and lower radiation patches is 5 groups of identical ellipses, and the ellipses are evenly distributed on the periphery of the upper pentagonal feed patch. Each elliptical radiation patch is cut into two parts, an upper step half dipole and a lower step half dipole, at a distance of 5 / 6 from the inner vertex, with the upper step half dipole inside and the lower step half dipole outside, and the lower step half dipole is indented inward. The pentagonal feeding patch is connected to each upper step half dipole with a PIN diode. The upper pentagonal feeding patch is fed through the inner core of the coaxial line, the lower pentagonal feeding patch is connected to the coaxial line shell, and the upper and lower dipoles are fed differentially. The tail of the lower step half dipole is connected to the DC metal bias column through the upper DC bias line and the lower DC bias line. When the antenna is in use, a pair of dipoles with an angle difference of 180° in the upper and lower layers are selected each time to work, and the designed antenna can work in a linear polarization state with 5 uniform angle intervals. When simulating the antenna, the upper diode, the lower diode, the choke inductor and other components are substituted into the simulation software through an equivalent circuit model.

[0012] Preferably, the upper pentagonal feeding patch and the lower pentagonal feeding patch are respectively located in the central parts of the upper and lower layers of the dielectric substrate.

[0013] Preferably, the upper step half dipole and the lower step half dipole are obtained by truncating 10 identical elliptical structures, wherein five elliptical dipole arms are located in the upper layer with an angular interval of 72°; and the other five elliptical dipole arms are located in the lower layer with an angular interval of 72°.

[0014] Preferably, the upper diode and the lower diode are Bar02-L in type and 0402 in package, and are evenly rotated and arranged along the center of the dielectric substrate with an angular interval of 72°. The inductor is VHF160808H68NJJT in type 0402.

[0015] Preferably, the compact broadband polarization reconfigurable antenna based on a stepped dipole has a completely rotationally symmetric distribution feature in structure.

[0016] Preferably, the coaxial feed line is located at the center of the antenna, the outer conductor of the coaxial line is connected to the lower feeding plate, and the inner conductor is connected to the upper feeding plate to achieve differential feeding.

[0017] Preferably, the metal floor is circular, connected to the outer conductor of the coaxial feeder at the center of the circle, and disconnected from the inner conductor of the coaxial feeder.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This antenna greatly reduces the electrical size of the antenna through the stepped dipole shape design, realizing the miniaturization design of the antenna.

[0020] 2. This antenna is designed with a stepped dipole shape, the dipole is cut off in the middle, and the imaginary impedance of the antenna is adjusted by introducing the capacitance effect, so that the working frequency band of the antenna is expanded, realizing the broadband design of the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a three-dimensional structure of an embodiment of the present invention;

[0022] Figure 2 It is an upper radiation patch diagram of an embodiment of the present invention;

[0023] Figure 3 The lower radiation map of the embodiment of the present invention;

[0024] Figure 4 is a diagram of the upper radiation patch of a common elliptical reconfigurable antenna for comparison with the embodiment of the present invention;

[0025] Figure 5 A diode equivalent circuit model used in the embodiment of the present invention;

[0026] Figure 6 An inductor equivalent circuit model used in the embodiment of the present invention;

[0027] Figure 7 is a comparison diagram of return loss curves of an embodiment of the present invention and a common elliptical dipole reconfigurable antenna;

[0028] Figure 8 1 is a curve showing the variation of the normal main polarization and cross-polarization gain with frequency according to an embodiment of the present invention.

[0029] Fig. 9 The main polarization and cross-polarization directional diagrams of the E-plane and H-plane at 1.0 GHz of the embodiment of the present invention;

[0030] Fig.10 The main polarization and cross-polarization directional diagrams of the E-plane and H-plane at 1.4 GHz of the embodiment of the present invention;

[0031] Fig.11 1. The main polarization and cross-polarization directivity diagrams of the E-plane and H-plane at 1.8 GHz according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figure 1 , Figure 2 and Figure 3 As shown, the present invention provides a technical solution: a compact broadband polarization reconfigurable antenna based on a stepped dipole, comprising a dielectric substrate, an upper stepped half dipole, a lower stepped half dipole, an upper DC bias line, a lower DC bias line, a metal floor, a DC metal bias column, a coaxial feed line, an upper pentagonal feed patch, a lower pentagonal feed patch, an upper diode, a lower diode, and a choke inductor.

[0035] like Figure 2 and Figure 3As shown, the upper and lower patch structures of the compact broadband polarization reconfigurable antenna based on a stepped dipole are symmetrically distributed at 180° as a whole. The main shapes of the upper and lower radiation patches are 5 groups of identical ellipses, and the ellipses are evenly distributed around the periphery of the upper pentagonal feed patch. The major axis of the ellipse is 27.5 mm, and the axial ratio is 0.4. Each elliptical radiation patch is truncated in the middle into an upper stepped half-dipole and a lower stepped half-dipole, with the upper stepped half-dipole inside and the lower stepped half-dipole outside. The lower stepped half-dipole is indented inward by 10 mm.

[0036] like Figure 2 and Figure 3 As shown, the pentagonal feeding patch is connected to each upper step half dipole by a PIN diode. The upper pentagonal feeding patch is fed through the inner core of the coaxial line, the lower pentagonal feeding patch is connected to the outer shell of the coaxial line, and the upper and lower dipoles are fed differentially. The tail of the lower step half dipole is connected to the DC metal bias column through the upper DC bias line and the lower DC bias line.

[0037] like Figure 2 and Figure 3 As shown, the physical size of the upper diode and the lower diode is 1mm*0.6mm, and the physical size of the choke inductor is 0.6*0.4mm.

[0038] like Figure 2 and Figure 3 As shown, the upper pentagonal feeding patch and the lower pentagonal feeding patch are respectively located in the central part of the upper and lower layers of the dielectric substrate, and the length of the feed patch vertex from the center is 5.1 mm. When the antenna is in use, two pairs of dipoles with an angle difference of 180° in the upper and lower layers are selected each time to work. The designed antenna can work in 5 linear polarization states with uniform angle intervals of 72°.

[0039] like Figure 2 and Figure 3 As shown, the upper stepped half dipole and the lower stepped half dipole are obtained by truncating 10 identical elliptical structures, of which five elliptical dipole arms are located in the upper layer with an angle interval of 72°; the other five elliptical dipole arms are located in the lower layer with an angle interval of 72°. The upper diode and the lower diode have the same model and package, and are evenly rotated and arranged along the center of the dielectric substrate with an angle interval of 72°. The compact broadband polarization reconfigurable antenna based on stepped dipole has a completely rotationally symmetrical distribution feature in structure.

[0040] like Figure 1As shown, the coaxial feed line is located at the center of the antenna, the outer conductor of the coaxial line is connected to the lower feeding plate, and the inner conductor is connected to the upper feeding plate to achieve differential feeding. The coaxial feed line 11 is located at the center of the antenna, the outer conductor radius Ro = 1.1mm, and the inner conductor radius Ri = 0.51mm.

[0041] like Figure 1 As shown, the substrate thickness of the metal floor is 1 mm, the radius is 48 mm, and the corresponding low-frequency electrical size is 0.314λ.

[0042] like Figure 4 As shown, the upper radiation patch of the common elliptical reconfigurable antenna compared with the embodiment of the present invention is five groups of ellipses, the major axis of the ellipse is 27.5 mm, the axis ratio is 0.4, and the corresponding low-frequency electrical size is 0.428λ.

[0043] When this embodiment is working, an external bias device bias tee is used to feed a 0V DC voltage to the inner and outer conductors of the coaxial line, and a 1.5V DC voltage is passed through the outer DC bias column to control the on-off of the diode. Different polarization states can be achieved through different diode on-off combinations.

[0044] Based on the above, the modeling and simulation were carried out in HFSS. During the simulation, the upper diode, lower diode, choke inductor and other components were substituted into the simulation software through the equivalent circuit model. When the first upper dipole and the first lower dipole were turned on, the simulation results were as follows: Figure 7-11 As shown. Figure 7 It can be concluded that the compact broadband polarization reconfigurable antenna based on the stepped dipole provided in this embodiment has an impedance bandwidth of 0.98-1.80 GHz and a relative bandwidth of 57.1%, and has broadband characteristics.

[0045] Depend on Figure 9-11 From the radiation patterns of each frequency point (1.0GHz, 1.4GHz, 1.8GHz) in the working frequency band, it can be seen that the antenna radiation patterns at each frequency point have good unidirectional radiation characteristics; the cross polarization is much lower than the main polarization, and has good linear polarization characteristics.

[0046] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A compact broadband polarization reconfigurable antenna based on a stepped dipole, characterized in that: It comprises a dielectric substrate (1), an upper step half dipole (2), a lower step half dipole (3), an upper DC bias line (4), a lower DC bias line (5), a metal floor (6), a DC metal bias column (7), a coaxial feed line (8), an upper pentagonal feed patch (9), a lower pentagonal feed patch (10), an upper diode (11), a lower diode (12), and a choke inductor (13); The upper step half dipole (2), the lower step half dipole (3), the upper DC bias line (4), the lower DC bias line (5), the upper pentagonal feeding patch (9), the lower pentagonal feeding patch (10), the upper diode (11), the lower diode (12), and the choke inductor (13) of the compact broadband polarization reconfigurable antenna are distributed symmetrically at 180° as a whole; The main body shapes of the upper and lower radiation patches are 5 groups of identical ellipses, and the ellipses are evenly distributed around the periphery of the upper pentagonal feeding patch (9) and the lower pentagonal feeding patch (10); Each elliptical radiation patch is cut into two parts in the middle, namely, an upper step half dipole (2) and a lower step half dipole (3), wherein the inner part is the upper step half dipole (2) and the outer part is the lower step half dipole (3), and the lower step half dipole (3) is indented inwards; The upper pentagonal feeding patch (9), the lower pentagonal feeding patch (10) and each upper step half dipole (2) are connected to each other via an upper diode (11) and a lower diode (11); the upper pentagonal feeding patch (9) is fed via the inner core of the coaxial feed line (8), the lower pentagonal feeding patch (10) is connected to the outer shell of the coaxial feed line (8), and the upper and lower dipoles are fed differentially; the tail of the lower step half dipole (3) is connected to the DC metal bias column (7) via an upper DC bias line (4) and a lower DC bias line (5); When the antenna is in use, a pair of upper step half dipoles (2) and lower step half dipoles (3) with an angle difference of 180 degrees are selected each time to work, and the designed antenna can work in five linear polarization states with uniform angle intervals; When simulating the antenna, the upper diode (11), the lower diode (12) and the choke inductor (13) are substituted into the simulation software through an equivalent circuit model.

2. The compact broadband polarization reconfigurable antenna based on a stepped dipole according to claim 1, characterized in that: The upper pentagonal feeding patch (9) and the lower pentagonal feeding patch (10) are respectively located at the central parts of the upper and lower layers of the dielectric substrate (1).

3. The compact broadband polarization reconfigurable antenna based on a stepped dipole according to claim 1, characterized in that: The upper step half dipole (2) and the lower step half dipole (3) are obtained by cutting off 10 identical elliptical structures, wherein five elliptical dipole arms are located in the upper layer with an angular interval of 72°; the other five elliptical dipole arms are located in the lower layer with an angular interval of 72°; the upper layer diode (11) and the lower layer diode (12) are of the same model and package, and are evenly rotated and arranged along the center of the dielectric substrate (1) with an angular interval of 72°; the compact broadband polarization reconfigurable antenna has a completely rotationally symmetrical distribution feature in structure.

4. The compact broadband polarization reconfigurable antenna based on a stepped dipole according to claim 1, characterized in that: The coaxial feed line (8) is located at the center of the antenna, the outer conductor of the coaxial feed line (8) is connected to the lower DC bias line (5), and the inner conductor is connected to the upper DC bias line (4), so as to realize differential feeding.

5. The compact broadband polarization reconfigurable antenna based on a stepped dipole according to claim 1, characterized in that: The metal floor (6) is circular and is connected to the outer conductor of the coaxial feeder (8) at the center of the circle, and is disconnected from the inner conductor of the coaxial feeder (8).

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