Dual-frequency polarization reconfigurable circular slot antenna

Abstract

The utility model relates to a dual-frequency polarization reconfigurable circular slot antenna, which belongs to the field of communication and comprises a dielectric substrate, a radiation patch arranged on the upper surface of the dielectric substrate and a grounding plate arranged on the lower surface of the dielectric substrate. The radiation patch comprises two metal strips which are perpendicular to each other, a concentric annular gap is formed in the grounding plate, each metal strip is coupled with the concentric annular gap to excite two resonant frequencies, a circular gap is formed in the concentric annular gap, the concentric annular gap and the circular gap are mutually coupled, and the two resonant frequencies are excited. And dual-band polarization reconfiguration is realized. According to the utility model, the reconstruction of the polarization modes of 2.5 GHz and 5.8 GHz frequency bands is realized, through the symmetrical design of the structure, the rotation directions of circular polarization radiation are different during the feeding of different single ports, the miniaturization requirement is met, the size is small, the profile is thin, the manufacturing process is simple, and the cost is low.

Description

Technical Field

[0001] The utility model relates to the field of communications, in particular to a dual-frequency polarization reconfigurable circular slot antenna. Background Art

[0002] With the rapid development of mobile communication technology, 4G / 5G wireless communications gradually coexist in one system. In order to be compatible with signals from different systems, it is often required to use one antenna instead of multiple antennas to receive electromagnetic waves in the 2.5GHz and 5.8GHz frequency bands and different polarization modes, which can increase channel capacity while reducing installation costs and equipment size. This situation has prompted the development of antennas towards miniaturization, multi-mode, dual-frequency and even multi-frequency, and has further promoted the research on reconfigurable microstrip antenna technology.

[0003] However, the development of microstrip dual-frequency polarization reconfigurable antennas at this stage still faces many problems that need to be solved; on the one hand, microstrip dual-frequency antennas face many difficulties in miniaturization: the use of array or stacking methods will lead to excessive antenna size or high profile, complex structure, and increased production costs, while the use of a single radiating unit can maintain the profile but is difficult to design. On the other hand, polarization reconfigurable antennas also face many difficulties: loading too many RF switches will lead to a larger antenna volume, adding a matching network will lead to a complex overall structure, changing the mechanical structure will lead to complex processes and difficult integration, and the use of new materials will lead to high production costs.

[0004] Circular slot antennas are widely used in various fields due to their simple structure, light weight, thin profile, and easy manufacturing. However, there are not many designs for circular slot antennas working in the 2.5GHz and 5.8GHz frequency bands. The main reason is that the maximum high-low resonant frequency ratio of traditional dual-frequency circular slot antennas can only reach 1.74, and it is not possible to achieve simultaneous operation of 2.5GHz and 5.8GHz dual-frequency bands. In addition, there are many studies on polarization reconfigurability of circular slot antennas, but most of them are achieved by loading switches, feeding networks, using new materials, etc., and have not overcome the above difficulties. Utility Model Content

[0005] The purpose of the utility model is to overcome the shortcomings of the prior art and provide a dual-frequency polarization reconfigurable circular slot antenna to solve the deficiencies of the prior art.

[0006] The purpose of the utility model is achieved by the following technical solutions: a dual-frequency polarization reconfigurable circular slot antenna, the antenna comprising a dielectric substrate, a radiation patch is arranged on the upper surface of the dielectric substrate, and a ground plate is arranged on the lower surface of the dielectric substrate;

[0007] The radiation patch includes two mutually perpendicular metal strips, and a concentric ring gap is opened on the ground plate. Each metal strip is coupled with the concentric ring gap to excite two resonant frequencies. A circular gap is arranged in the concentric ring gap, so that the concentric ring gap and the circular gap are coupled with each other to achieve dual-band polarization reconfiguration.

[0008] The center of the circular gap is not at the same point as the center of the concentric ring gap.

[0009] Each metal strip has a feeding port, one of the two feeding ports is used for feeding, and the other is connected to a matching load.

[0010] The utility model has the following advantages: a dual-frequency polarization reconfigurable circular slot antenna, which realizes the reconstruction of polarization modes in the 2.5GHz and 5.8GHz frequency bands, and realizes different rotation directions of circular polarization radiation when different single-port feeding is achieved through the symmetric design of the structure, meets the miniaturization requirements, has a small size, a thin profile, a simple manufacturing process and a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a top view schematic diagram of the utility model;

[0012] Figure 2 It is a bottom view schematic diagram of the utility model;

[0013] Figure 3 It is a schematic diagram of simulation results of the relationship between reflection coefficient and frequency of the utility model;

[0014] Figure 4 It is a schematic diagram of simulation results of the relationship between the axial ratio and the frequency of the utility model;

[0015] Figure 5 The gain of the antenna fed by only the first feeding port of the utility model at 2.5 GHz and 5.8 GHz frequency points is Figure 1 ;

[0016] Figure 6 The gain of the antenna fed by only the first feeding port of the utility model at 2.5 GHz and 5.8 GHz frequency points is Figure 2 ;

[0017] Figure 7 The gain of the antenna fed by only the second feeding port of the utility model at 2.5 GHz and 5.8 GHz frequency points is Figure 1 ;

[0018] Figure 8 The gain of the antenna fed by only the second feeding port of the utility model at 2.5 GHz and 5.8 GHz frequency points is Figure 2 .

[0019] In the figure: 1-dielectric substrate, 2-radiation patch, 3-ground plate, 4-metal strip, 5-concentric ring gap, 6-circular gap, 7-first feeding port, 8-second feeding port. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. The utility model is further described below in conjunction with the drawings.

[0021] like Figure 1 and Figure 2 As shown, the utility model specifically relates to a dual-frequency polarization reconfigurable circular slot antenna. The antenna is mainly composed of three parts: a dielectric substrate 1, a radiation patch 2, and a ground plane 3. The feeding method is microstrip line feeding. The dielectric substrate 1 adopts an FR4 epoxy resin board with a thickness of 1.6 mm and a dielectric constant of 4.4. The radiation patch 2 is located on the upper surface of the dielectric substrate and consists of two mutually perpendicular metal strips 4. The characteristic impedance is equal to 50 ohms. At the same time, it serves as a microstrip feeding transmission line. Each dimensional feeding transmission line has a feeding port, such as Figure 1 The ground plane 3 is located on the lower surface of the dielectric substrate 1 and is replaced by a thin layer of metal, and has a concentric annular gap 5 and an eccentric circular gap 6.

[0022] The utility model uses two mutually perpendicular 50 ohm microstrip feed lines to couple with a concentric circular ring gap 5 on the ground plate 3, excites two resonant frequencies, and realizes the dual-band working effect of 2.5GHz and 5.8GHz. Since the radiation patch 2 naturally satisfies the phase difference of 90°, circular polarization radiation can be realized by single-port feeding. By adding an eccentric circular gap 6 on the ground plate 3, the antenna axial ratio is reduced to less than 3dB, realizing the left-handed (or right-handed) circular polarization radiation characteristics in the 2.5GHz and 5.8GHz frequency bands when single-port feeding is used.

[0023] Finally, without increasing the volume and thickness of the dual-band antenna, the dual feeding ports are fed simultaneously (with equal amplitude and phase), and the left-hand circularly polarized wave and the right-hand circularly polarized wave are superimposed to synthesize a linearly polarized wave.

[0024] like Figure 3 As shown in the figure, there are two working frequency bands with a reflection coefficient less than -10dB: the first working frequency band is 2.13GHz-2.82GHz, and the reflection coefficient is as low as -35dB at 2.5GHz; the second working frequency band is 4.97GHz-7.90GHz, and the reflection coefficient is as low as -18dB at 5.8GHz and 7.5GHz. Figure 4 As shown, when single-port feeding is used, the axial ratio reaches the lowest at 2.5 GHz in the first working frequency band and 5.8 GHz in the second working frequency band. 2.5 GHz in the first working frequency band and 5.8 GHz in the second working frequency band are both generated by the concentric circular gap 5, and 7.5 GHz in the second working frequency band is generated by the eccentric circular gap 6.

[0025] When the first feeding port 7 and the second feeding port 8 are fed separately, the antenna realizes circular polarization radiation characteristics in the 2.5 GHz and 5.8 GHz frequency bands (the ratio of high and low resonant frequencies reaches 2.32), and realizes linear polarization radiation characteristics in the 7.5 GHz frequency band. The working bandwidths are basically the same, as follows:

[0026] The impedance bandwidth of the first working frequency band is 27.6% (2.13GHz-2.82GHz), the 3dB axial ratio bandwidth is 11.2% (2.35GHz-2.63GHz), and the actual effective working frequency band is 2.35GHz-2.63GHz.

[0027] The impedance bandwidth of the second working frequency band is 45.5% (4.97GHz-7.90GHz), the 3dB axial ratio bandwidth is 14.7% (5.36GHz-6.21GHz), the circular polarization effective working frequency band is 5.36GHz-6.21GHz, and the linear polarization effective working frequency band is 7.30GHz-7.80GHz (axial ratio AR>15dB).

[0028] When the first feeding port 7 and the second feeding port 8 are fed simultaneously (equal amplitude and in phase), the axial ratio in the entire working frequency band is greater than 40dB, indicating that the linear polarization purity of the antenna is very high, and the effective working bandwidth is equal to the impedance bandwidth. The impedance bandwidth of the first working frequency band is 27.6% (2.13GHz-2.82GHz), and the impedance bandwidth of the second working frequency band is 45.5% (4.97GHz-7.90GHz).

[0029] like Figure 5-Figure 8 As shown, the polarization conditions at 2.5 GHz and 5.8 GHz when only the first feeding port 7 and only the second feeding port 8 are fed are taken as examples to further illustrate the circular polarization characteristics. Figure 5 and Figure 6It can be seen that when only the first feeding port 7 is used, the antenna generates left-hand circularly polarized electromagnetic waves in the +z-axis direction at 2.5 GHz and 5.8 GHz. Figure 7 and Figure 8 It can be seen that when only the second feeding port 8 is fed, the antenna generates right-hand circularly polarized electromagnetic waves in the +z-axis direction at 2.5 GHz and 5.8 GHz frequencies, and the two have opposite rotation directions.

[0030] The utility model adopts two mutually perpendicular radiation patches 2 as two 50 ohm microstrip feed lines at the same time, and a method of coupling with a ground plate 3 with a concentric circular ring gap 5 and an eccentric circular gap 6 is opened, so as to realize dual-band operation and reconstruction of polarization modes of 2.5GHz and 5.8GHz bands, that is, to realize left-hand circular polarization or right-hand circular polarization radiation characteristics of 2.5GHz and 5.8GHz bands when a single port is fed, and to realize linear polarization radiation characteristics of 2.5GHz and 5.8GHz bands when dual ports are fed simultaneously. The antenna has the characteristics of miniaturization, thin profile, simple structure, high utilization rate, etc., which can effectively reduce the repeatability of equipment and meet the use requirements in multiple scenarios.

[0031] The above is only a preferred embodiment of the utility model. It should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used for various other combinations, modifications and improvements, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge in the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. A dual-frequency polarization reconfigurable circular slot antenna, characterized in that: The antenna comprises a dielectric substrate (1), a radiation patch (2) is arranged on the upper surface of the dielectric substrate (1), and a grounding plate (3) is arranged on the lower surface of the dielectric substrate (1); The radiation patch (2) comprises two mutually perpendicular metal strips (4), a concentric annular gap (5) is provided on the ground plane (3), each metal strip (4) is coupled with the concentric annular gap (5), two resonant frequencies are excited, and a circular gap (6) is provided in the concentric annular gap (5), so that the concentric annular gap (5) and the circular gap (6) are coupled with each other, thereby realizing dual-band polarization reconfiguration.

2. The dual-frequency polarization reconfigurable circular slot antenna according to claim 1, characterized in that: The center of the circular gap (6) and the center of the concentric annular gap (5) are not located at the same point.

3. The dual-frequency polarization reconfigurable circular slot antenna according to claim 1, characterized in that: Each metal strip (4) has a feeding port, one of the two feeding ports is used for feeding, and the other is connected to a matching load.

Images