Broadband polarization reconfigurable antenna for exciting multiple resonance modes through overlapping coupling

Abstract

The invention discloses a broadband polarization reconfigurable antenna for exciting multiple resonance modes through overlapping coupling. The broadband polarization reconfigurable antenna comprises an upper-layer radiation patch, a dielectric substrate, an upper-layer direct-current bias circuit, a lower-layer radiation patch, a metal floor, a floor substrate, a direct-current metal column, a coaxial feeder line and a double-layer metal feed piece. The upper and lower layer radiation patches are seven groups of identical ellipses and are uniformly distributed on the peripheries of the upper and lower layer feed patches. And the upper-layer radiation patch and the lower-layer radiation patch have a large-area overlapping part in a vertical space. By controlling the on-off of the PINs, the two adjacent groups of upper-layer radiation patches and lower-layer radiation patches are gated to work each time, and the designed antenna can work in a linear polarization state at seven different angles. Through special dipole shape design and slotting processing and by adopting an overlapping coupling mode, the antenna forms a plurality of resonant modes, and the working bandwidth is greatly expanded. The antenna has the characteristics of large linear polarization number, wide working frequency band and the like.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a broadband polarization reconfigurable antenna that excites multiple resonance modes through overlapping coupling and a design method thereof. Background Art

[0002] The rapid progress of information technology has led to the rapid development of wireless communication technology. The requirements of wireless communication systems for antennas have become increasingly stringent, and the antennas they are equipped with need to have high speed, wide bandwidth, and strong anti-interference performance. In the past few decades of applications in various fields, the role of these technical requirements in improving the quality of communication links has been fully verified. As a direct factor affecting the performance of the entire system, the working performance of the antenna has attracted much attention. In recent years, multi-polarization reconfigurable antennas have shown significant advantages in polarization modulation and anti-multipath fading and have received widespread attention.

[0003] From the published literature and patents, the realized multi-polarization reconfigurable antennas mainly have two problems: insufficient number of linear polarizations (less than or equal to 4) and narrow working frequency band (less than or equal to 20%). For example:

[0004] Yang Yang et al. designed a polarization and pattern reconfigurable antenna unit in the document “A Novel Boresight and Conical Pattern Reconfigurable Antenna With the Diversity of 360° Polarization Scanning”, which can operate in 8 different polarization states, but the operating frequency is only 2.5%.

[0005] The Chinese invention patent (CN108963449A) proposes a multi-linear polarization reconfigurable antenna with an integrated artificial magnetic conductor and a design method thereof. Although the multi-linear polarization characteristics are achieved, the working bandwidth in each polarization state is only 20%, which is relatively narrow and cannot meet the application requirements of multi-band and multi-function.

[0006] A Chinese invention patent (CN106229668A) proposes a broadband polarization reconfigurable base station antenna, which realizes switching of four polarization states through two sets of cross-distributed oscillators. However, its feeding network part is a Wilkinson power divider with a relatively complex structure, and the number of linear polarizations is insufficient to adapt to complex communication environments.

[0007] A Chinese invention patent (CN114243279B) proposes a broadband multi-polarization reconfigurable antenna loaded with a double-layer metal sheet. A wider bandwidth is achieved by loading a double-layer metal sheet, but its profile height is relatively high and cannot be applied to most low-profile working requirements.

[0008] In summary, designing multi-polarization reconfigurable antennas with broadband performance has important research and application value. Summary of the invention

[0009] In order to overcome the shortcomings and deficiencies of the prior art, the present invention provides a broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling. The present invention adopts the following technical solutions:

[0010] A broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling, characterized in that it includes an upper layer feed sheet, an upper layer radiation patch, an upper layer DC bias circuit, a lower layer feed sheet, a lower layer radiation patch, a dielectric substrate, a DC metal column, a metal floor, a floor substrate, an upper layer PIN diode, a lower layer PIN diode, a coaxial feed line, and a bottom layer DC bias circuit. The radiation patch of the overlapping coupled broadband linear polarization reconfigurable antenna is in the shape of an ellipse with a portion cut off, and a gap is opened at the tail of the elliptical patch to enhance the bandwidth. The upper layer radiation patch and the lower layer radiation patch have a large area of ​​overlap in the vertical space. The floor substrate is a two-layer structure, which is used to simultaneously access the DC signal to the inner and outer metal layers of the coaxial feed line. The upper layer radiation patch and the lower layer radiation patch have seven groups respectively, which are evenly distributed around the central feed patch. The upper layer radiation patch and the upper layer feed sheet are connected by an upper layer PIN diode, and the tail of the upper layer radiation patch is connected to the DC metal column through an upper layer DC bias circuit. The lower radiation patch is connected to the lower feeding patch by a lower PIN diode, and the tail of the lower radiation patch is connected to the DC metal column through an upper DC bias circuit. The floor substrate is a two-layer structure, and a broadband bottom DC bias circuit is etched on the floor, which is used to simultaneously connect the DC signal to the inner and outer metal layers of the coaxial feeder.

[0011] Preferably, the overlapping coupled broadband polarization reconfigurable antenna operates by simultaneously selecting two groups of adjacent upper radiation patches and lower radiation patches, and the remaining upper radiation patches and lower radiation patches operate as a coupling structure, thereby generating multiple resonance points to expand the bandwidth.

[0012] Preferably, the central feed plate is in the shape of a heptagon and is located at the center of the upper and lower layers of the dielectric substrate respectively.

[0013] Preferably, the dielectric substrate, floor dielectric substrate, metal floor, and DC metal column are all circular or cylindrical; the upper radiation patch, lower radiation patch, upper feed patch, lower feed patch, and upper DC bias circuit are all seven groups of structures with the same shape and size, the same PIN diode model and package, and are all evenly rotated and arranged along the center of the dielectric substrate. The broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling has a completely rotationally symmetrical distribution.

[0014] 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.

[0015] Preferably, the dielectric floor is a two-layer structure, and the signal fed by the coaxial feed line is a superposition of a radio frequency RF signal and a grounded direct current DC signal.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This antenna adopts an overlapping coupled dipole design, adopts a strategy of simultaneously selecting two groups of adjacent upper radiation patches and lower radiation patches to work, and the remaining upper radiation patches and lower radiation patches work as a coupled structure. By exciting multiple resonant modes, the antenna has broadband characteristics while achieving multi-polarization reconfigurable functions.

[0018] 2. This antenna is designed with a special elliptical dipole shape and a slit at the tail end, which better controls the radiation impedance of the antenna and improves the impedance matching of the antenna within a wide bandwidth.

[0019] 3. The ground plane of this antenna is carefully designed to simultaneously feed a DC signal to the inner and outer conductors of the coaxial line without using an external bias device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a three-dimensional structure of an embodiment of the present invention;

[0021] Figure 2 It is an upper layer etching shape diagram of an embodiment of the present invention;

[0022] Figure 3 It is a lower layer etching shape diagram of an embodiment of the present invention;

[0023] Figure 4 is a bottom view of an embodiment of the present invention;

[0024] Figure 5 This is a current distribution diagram of an embodiment of the present invention when working in a polarized state;

[0025] Figure 6 is a curve showing the change of return loss with frequency according to an embodiment of the present invention;

[0026] Figure 7 The main polarization and cross-polarization directional diagrams of the E-plane and H-plane at 3 GHz of the embodiment of the present invention;

[0027] Figure 8 The main polarization and cross-polarization directional diagrams of the E-plane and H-plane at 4 GHz of the embodiment of the present invention;

[0028] Fig. 9 The main polarization and cross-polarization directional diagrams of the E-plane and H-plane at 5 GHz of the embodiment of the present invention;

[0029] Fig.10 1 and 2 are main polarization and cross polarization radiation patterns of the E-plane and H-plane at 6 GHz according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] 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.

[0031] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, the present invention provides a technical solution: a broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling, including an upper layer feed sheet 1, an upper layer radiation patch 2, an upper layer DC bias circuit 3, a lower layer feed sheet 4, a lower layer radiation patch 5, a dielectric substrate 6, a DC metal column 7, a metal floor 8, a floor substrate 9, an upper layer PIN diode 10, a lower layer PIN diode 11, a coaxial feed line 12, and a bottom layer DC bias circuit 13. The upper layer radiation patch 2 and the lower layer radiation patch 5 have a large overlapping part in the vertical space. The upper layer radiation patch 2 and the lower layer radiation patch 5 have seven groups respectively, which are evenly distributed around the upper layer feed sheet 1 and the lower layer feed sheet 4. The radius of the dielectric substrate 6 is R1=30mm, and the thickness is T1=1.5mm.

[0033] like Figure 1 As shown, the coaxial feed line 11 is located at the center of the antenna, the outer conductor radius Ro = 1.1 mm, the inner conductor radius Ri = 0.51 mm, the outer conductor of the coaxial line is connected to the lower feeding plate 4, and the inner conductor is connected to the upper feeding plate 1 to achieve differential feeding of the dipole.

[0034] like Figure 2As shown, the upper radiation patch 2 is in the shape of an ellipse with a portion cut off, the major axis is L1=11mm, the axis ratio Ra=0.4, and a gap is opened at the tail of the upper radiation patch 2 to enhance the bandwidth. The upper radiation patch 2 is connected to the upper feed patch 1 by an upper PIN diode 10, and the tail of the upper radiation patch 2 is connected to the DC metal column 7 through the upper DC bias circuit 3.

[0035] like Figure 3 As shown, the lower radiation patch 5 is in the shape of an ellipse with a portion cut off, the major axis is L1=11mm, the axis ratio Ra=0.4, and a gap is opened at the tail of the lower radiation patch 5 to enhance the bandwidth. The lower radiation patch 5 is connected to the lower feeding patch 4 by the lower PIN diode 11, and the tail of the lower radiation patch 5 is connected to the DC metal column 7 through the upper DC bias circuit 3.

[0036] like Figure 4 As shown, the floor substrate 9 is a two-layer structure with a thickness of T2 = 1 mm and a radius of R2 = 40 mm. A broadband DC bias circuit is etched on the floor to simultaneously connect the DC signal to the inner and outer metal layers of the coaxial feed line 12.

[0037] like Figure 2 and Figure 3 As shown, the upper layer feeding plate 1 and the lower layer feeding plate 4 are heptagonal in shape and are located at the upper and lower layers center of the dielectric substrate 6 respectively.

[0038] like Figure 1 As shown, the dielectric substrate 6, floor dielectric substrate 9, metal floor 8, and DC metal column 7 are all circular or cylindrical; the upper radiation patch 2, the lower radiation patch 5, the upper feeding patch 1, the lower feeding patch 4, and the upper DC bias circuit 3 are all seven groups of structures with the same shape and size, the upper PIN diode 10 and the lower PIN diode 11 have the same model and package, the model is Bar-02L, the package is 0402, and they are all evenly rotated and arranged along the center of the dielectric substrate 6. The broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling has a completely rotationally symmetrical distribution.

[0039] When the present embodiment is working, there is no need to use an external bias device. It is only necessary to apply a positive 1.5V voltage to the DC metal column 7 distributed at the edge and a 0V ground voltage to the metal floor 8 to control the on-off of the diode. Different polarization states can be achieved through different diode on-off combinations.

[0040] Based on the above, modeling and simulation were performed in HFSS, and the results were as follows Figure 5-10 As shown. Figure 6It can be concluded that the broadband polarization reconfigurable antenna provided by this embodiment, which excites multiple resonant modes through overlapping coupling, has an impedance bandwidth of 80%, covers a frequency band of 3-7 GHz, and has broadband characteristics. The antenna current diagrams at each resonant point are shown in FIG. Figure 5 As shown. , it can be seen that the three resonance modes are different.

[0041] Depend on Figure 7-10 From the radiation patterns of each frequency point (3GHz, 4GHz, 5GHz, 6GHz) 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.

[0042] 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 broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling, characterized in that: It comprises an upper feeding sheet (1), an upper radiation patch (2), an upper DC bias circuit (3), a lower feeding sheet (4), a lower radiation patch (5), a dielectric substrate (6), a DC metal column (7), a metal floor (8), a floor substrate (9), an upper PIN diode (10), a lower PIN diode (11), a coaxial feed line (12), and a bottom DC bias circuit (13); The upper radiation patch (2) and the lower radiation patch (5) of the overlapping coupled broadband polarization reconfigurable antenna are both ellipses with a portion cut off, and a gap is opened at the tail of the radiation patch (2) to expand the bandwidth; The upper radiation patch (2) and the lower radiation patch (5) have a relatively large overlapping portion in the vertical space; The overlapping coupled broadband polarization reconfigurable antenna operates by simultaneously selecting two groups of adjacent upper radiation patches (2) and lower radiation patches (5), and the remaining upper radiation patches (2) and lower radiation patches (5) operate as a coupling structure, thereby generating multiple resonance points to expand the bandwidth; The upper radiation patch (2) and the lower radiation patch (5) each have seven groups, which are evenly distributed around the central feed patch. The upper radiation patch (2) and the upper feed patch (1) are connected by an upper PIN diode (2), and the tail of the upper radiation patch (2) is connected to the DC metal column (7) through an upper DC bias circuit (3). The lower radiation patch (5) and the lower feed patch (4) are connected by a lower PIN diode (11), and the tail of the lower radiation patch (5) is connected to the DC metal column (7) through an upper DC bias circuit (3); The floor substrate (9) is a two-layer structure, and a broadband bottom layer DC bias circuit (13) is etched on the floor, which is used to simultaneously connect a DC signal to the inner and outer metal layers of the coaxial feeder (12).

2. The broadband polarization reconfigurable antenna for exciting multiple resonant modes by overlapping coupling according to claim 1, characterized in that: The upper layer feeding plate (1) and the lower layer feeding plate (4) are heptagonal in shape and are located at the upper and lower layer centers of the dielectric substrate (6) respectively.

3. The broadband polarization reconfigurable antenna for exciting multiple resonant modes by overlapping coupling according to claim 1, characterized in that: The dielectric substrate (6), DC metal column (7), metal floor (8), and floor dielectric substrate (9) are all circular or cylindrical; the upper feeding plate (1), the upper radiation patch (2), the upper DC bias circuit (3), the lower feeding plate (4), and the lower radiation patch (5) are all seven groups of structures with the same shape and size; the upper PIN diode (10) and the lower PIN diode (11) are structures with the same model and package, and are evenly arranged in rotation along the center of the dielectric substrate (6). The broadband polarization reconfigurable antenna that excites multiple resonant modes through overlapping coupling has a completely rotationally symmetrical distribution feature.

4. The broadband polarization reconfigurable antenna for exciting multiple resonant modes by overlapping coupling according to claim 1, characterized in that: The coaxial feed line (12) 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, so as to realize differential feeding.

5. The broadband polarization reconfigurable antenna for exciting multiple resonant modes by overlapping coupling according to claim 1, characterized in that: The floor substrate (9) is a two-layer structure, and the signal fed into the coaxial feed line (12) is a superposition of a radio frequency (RF) signal and a processed grounded direct current (DC) signal.

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