CN107275765A - It is a kind of from the broadband circle polarized cross dipole antenna of phase shift - Google Patents

Abstract

The invention discloses a self-phase-shifting broadband circularly polarized crossed dipole antenna, which comprises a dielectric board and two dipole arms, wherein the two dipole arms are printed on two surfaces of the dielectric board respectively, and two The positional relationship of the dipole arms is: after rotating one dipole arm 180 degrees, it is symmetrical to the other dipole arm based on the dielectric plate; the dipole arm is composed of two branch patches at 90 degrees to each other, and the branches are rectangular Long strip or isosceles triangle shape; the two branches of the dipole arm have different lengths, and the phase difference of 90° is generated by adjusting the length difference of the two branches, so that the antenna has circular polarization characteristics; the antenna feed point is located on the dielectric plate center of. The antenna combines the characteristics of dipole antennas and circularly polarized antennas, and adopts a cross-dipole antenna with a 90° phase difference generated by a self-phase shifting structure, which not only eliminates the burden of complex power division networks, but also makes the size of the antenna smaller. Smaller and simpler in structure.

Description

A Self-Phase-Shifting Broadband Circularly Polarized Crossed-Dipole Antenna

technical field

The present invention relates to the field of self-phase-shifting circularly polarized cross-dipole antennas, and more specifically, to a self-phase-shifting wideband circularly-polarized cross-dipole antenna.

Background technique

With the increasing importance of communication in social life, the antenna as the eyes of wireless communication directly affects the quality and efficiency of communication. A half-wave dipole antenna is the basic unit of an antenna. Because of its simple structure, it is easy to design, and the array dipole structure can be changed at will to achieve ideal polarization requirements. Compared with the monopole antenna, the performance of the gain pattern has been improved to a certain extent, and a relatively satisfactory pattern characteristic can be obtained, and the dipole antenna is widely used because of its good radiation characteristics, wavelength shortening effect and resonance characteristics. In the field of microwave energy harvesting and transmission. By controlling the relationship between current amplitude, phase, and spatial position on multiple dipoles, dipole antennas can be widely used in base station antennas, circularly polarized antennas, and multiple-input multiple-output (MIMO) antennas.

The transmission of massive data requires the support of a suitable broadband wireless system, which puts forward higher and higher requirements for broadband communication equipment. Circularly polarized antennas have obvious advantages in anti-multipath interference, suppressing rain and fog interference, and improving channel capacity. The wireless communication system with circular polarization and broadband characteristics is one of the key technologies to meet the wireless transmission of massive data in the future. For circularly polarized antennas, it is required that the antenna can achieve a low axial ratio in a wide angle, so that the antenna can receive signals well no matter where it is at any angle.

Usually, the phase control can be well realized by the phase-shifted circularly polarized antenna generated by the power division feed network. However, due to the existence of complex power division network, the antenna is difficult to integrate, so it is difficult to apply to portable devices.

Contents of the invention

In order to overcome the deficiencies of the above-mentioned prior art, the present invention proposes a self-phase-shifting broadband circularly polarized crossed dipole antenna, which combines the characteristics of a dipole antenna and a circularly polarized antenna, and adopts a self-phase-shifting structure to generate a 90° The crossed dipole antenna with phase difference not only eliminates the burden of complex power division network, but also makes the size of the antenna smaller and the structure simpler.

In order to solve the above problems, the technical solution provided by the present invention is:

A self-phase-shifting broadband circularly polarized crossed dipole antenna, including a dielectric plate and two dipole arms, wherein the two dipole arms are printed on two sides of the dielectric plate, and the two dipoles The positional relationship of the arms is: after one dipole arm is rotated 180 degrees, it is symmetrical to the other dipole arm based on the dielectric plate; the dipole arm is composed of two branch patches at 90 degrees to each other, and the branches are in the shape of rectangular strips Or isosceles triangle shape; thereby lengthening the effective radiation area of the antenna, prolonging the effective flow path of the current, and making the antenna have a wider frequency band;

The lengths of the two branches of the dipole arm are different, and the phase difference of 90° is generated by adjusting the length difference of the two branches, so that the antenna has circular polarization characteristics;

The feed point of the antenna is located at the center of the dielectric plate.

Preferably, in order to achieve better matching for the antenna, the branches of the dipole arms are connected through a triangular structure.

Preferably, the antenna is fed through a flexible and rigid coaxial line, and the inner and outer conductors of the coaxial line are respectively connected to the dipole arms on the two sides of the dielectric plate. By changing the length, size and other parameters of the branch patch, the working frequency band and radiation characteristics of the antenna can be adjusted.

Preferably, when the branch is an isosceles triangle, the branch is an isosceles triangle structure or two connected triangle structures.

When only a simple self-phase-shifted quadrature half-wave oscillator composed of rectangular strips is used, since the resonant frequencies of the branches of two rectangular oscillators with different lengths are different, when the two resonant frequencies are close to a certain frequency point, the bandwidth will also increase accordingly. Gradually widen.

The rectangular long branch of the self-phase-shifted orthogonal half-wave oscillator is improved into an isosceles triangular branch, which can extend the effective flow path of the current, thereby realizing the widening of the frequency band.

Continuous improvement of one isosceles triangle structure of the dipole arm into two isosceles triangle structures can further increase and extend the effective flow path of the current, and better realize the widening of the frequency band of the antenna.

Compared with the prior art, the beneficial effects of the present invention are as follows: on the basis of conventional planar printing crossed dipoles, the present invention generates circular polarization by changing the length of the dipole arm to produce a 90° phase shift, and by sequentially increasing the triangular structure Then gradually widen the bandwidth of the dipole, and connect the two dipole branches in a triangle to achieve better matching of the antenna. Without weakening other performances, the broadband of the antenna can be realized to achieve better impedance. matching and better circular polarization. The antenna is a self-phase-shifting wideband circularly polarized crossed dipole antenna available for mobile equipment and environmental microwave energy transmission and acquisition systems.

Description of drawings

Figure 1 is a structural diagram of a long rectangular self-phase-shifting broadband circularly polarized crossed dipole antenna.

Fig. 2 is a S11 comparison diagram of the simulation and test of the long rectangular self-phase-shifted broadband circularly polarized crossed dipole antenna.

Fig. 3 is a structural diagram of a triangular self-phase-shifting broadband circularly polarized crossed dipole antenna.

Fig. 4 is a S11 comparison diagram of simulation and test of a triangular self-phase-shifting broadband circularly polarized crossed dipole antenna.

Fig. 5 is a structural diagram of two triangular self-phase-shifting broadband circularly polarized crossed dipole antennas.

Fig. 6 is a comparison diagram of S11 of simulation and test of two triangular self-phase-shifted broadband circularly polarized crossed dipole antennas.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

As shown in Figure 1, the structural diagram of a long rectangular self-phase-shifting broadband circularly polarized crossed dipole antenna. The two dipole arms of the dipole antenna are printed on the upper and lower sides of the dielectric board, and one dipole arm rotates After 180 degrees, it is symmetrical with the other dipole arm based on the dielectric plate. The dipole arms located on the same plane are composed of two branches perpendicular to each other and of different lengths. The different lengths of the two branches provide a phase difference of 90 degrees, forming the characteristics of circular polarization of the antenna. The feed point of the antenna is located in the center of the dielectric board, fed through the soft and rigid coaxial line, the inner and outer conductors of the coaxial line are respectively connected to the upper and lower dipole arms of the dielectric board, and two different dipole arms are connected through a triangular structure. The length of the dipole stub.

In this example, the antenna is printed on a FR-4 epoxy glass fiber cloth dielectric substrate with a thickness of 2 mm, a dielectric coefficient of 4.7, and a loss tangent of 0.01. The size of the dielectric substrate is 76mm * 62mm, and the long branch of the dipole radiation patch composed of rectangular strips forming 90 degrees is 33mm long and 4mm wide. The short branches are about 26mm in length and 4mm in width. The base length of the triangular connection structure is 12mm, and the height is 5mm.

In this example, the working frequency band of this antenna includes DCS1800, GSM1800, TD-SCDMA, WCDMA, and CDMA2000 wireless communication frequency bands. By modifying the size of the substrate, adjusting the parameters of the corresponding antenna patch and the size and thickness of the gradient ring, the antenna can be The working frequency band changes.

By using printed circuit board (PCB) technology, the physical prototype of the dual-band broadband circularly polarized cross-dipole antenna of this example can be produced. Due to the small patch of the feed port, the ordinary 3.5mm SMA interface cannot be used, so In this embodiment a soft-rigid coaxial feed is used. Figure 2 is the simulation and test comparison diagram of the antenna reflection coefficient S11. It can be seen that the antenna has a good impedance matching effect, the impedance bandwidth is about 1.57GHz to 2.24GHz, and the working frequency band includes multiple frequency bands of 3G and 4G communication, that is, The performance of this form of antenna can fully meet the actual requirements.

Example 2

As shown in Figure 3, in order to broaden the frequency band of the antenna and improve the circular polarization characteristics of the antenna, the rectangular strip is improved into a triangular structure. Since the triangular structure increases and prolongs the effective flow path of the current, the effect of bandwidth broadening is achieved. The different lengths of the two branches provide a phase difference of 90 degrees, forming the characteristics of the circular polarization of the antenna.

In this example, the antenna is printed on a FR-4 epoxy glass fiber cloth dielectric substrate with a thickness of 2 mm, a dielectric coefficient of 4.7, and a loss tangent of 0.01. The size of the dielectric substrate is 77mm * 65mm. On the two branches that are 90 degrees to each other, the larger triangle has a base length of 18mm and a height of 21mm, and the smaller triangle has a base length of 12mm and a height of 21mm. The bottom of the triangle connection structure The length is 9mm and the height is 21mm.

Also by using printed circuit board (PCB) technology, a physical prototype of a triangular self-phase-shifting broadband circularly polarized crossed-dipole antenna was fabricated. Among them, Figure 4 is a simulation and test comparison diagram of the antenna reflection coefficient S11. It can be seen that the bandwidth of this antenna is from 1.52GHz to 2.32GHz. Compared with the antenna in Example 1 above, the bandwidth is wider. The performance can fully meet the actual requirements, and the antenna can also have better performance.

Example 3

Figure 5 shows the structural diagram of two triangular self-phase-shifted broadband circularly polarized crossed dipole antennas. Under the condition of antenna performance, compared with one triangle, the advantage of two triangles is that the current path can continue to increase and extend. Thus the bandwidth can continue to widen. Also, a 90-degree phase difference is provided by adjusting the difference in the lengths of the two branches to form the characteristics of the circular polarization of the antenna.

In this example, the antenna is printed on a FR-4 epoxy glass fiber cloth dielectric substrate with a thickness of 2 mm, a dielectric coefficient of 4.7, and a loss tangent of 0.01. The size of the dielectric substrate is 73mm * 63mm. On the two branches that are 90 degrees to each other, the base length and height of the two triangles of the larger branch are 16mm, 14mm and 20mm, 7mm respectively, and the base length and height of the triangle of the smaller branch 12mm, 15mm and 12mm, 6mm respectively. The base length of the triangular connection structure is 9.15 mm, and the height is 15 mm.

Also by using printed circuit board (PCB) technology, a physical prototype of two triangular self-phase-shifting broadband circularly polarized crossed-dipole antennas was fabricated. Among them, Figure 6 is a simulation and test comparison diagram of the antenna reflection coefficient S11. It can be seen that the bandwidth of this antenna is 1.53 GHz to 2.4 GHz. Compared with the antenna in Example 2 above, the bandwidth is wider. The performance can fully meet the actual requirements.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (4)

1. A self-phase-shifting broadband circularly polarized crossed dipole antenna is characterized in that it comprises a dielectric plate and two dipole arms, wherein the two dipole arms are printed on two faces of the dielectric plate respectively , the positional relationship of the two dipole arms is: after one dipole arm is rotated 180 degrees, it is symmetrical to the other dipole arm based on the dielectric plate; the dipole arm is composed of two branch patches at 90 degrees to each other, The branches are in the shape of rectangular strips or isosceles triangles; The lengths of the two branches of the dipole arm are different, and the phase difference of 90° is generated by adjusting the length difference of the two branches, so that the antenna has circular polarization characteristics; The feed point of the antenna is located at the center of the dielectric plate. 2 . The self-phase-shifting broadband circularly polarized crossed dipole antenna according to claim 1 , wherein the branches of the dipole arms are connected by a triangular structure. 3 . 3. A kind of self-phase-shifting wideband circularly polarized crossed dipole antenna according to claim 1, characterized in that, the antenna is fed by a soft and rigid coaxial line, and the inner and outer conductors of the coaxial line are respectively connected to the medium on the dipole arms on both sides of the plate. 4. A kind of self-phase-shifting broadband circularly polarized crossed dipole antenna according to claim 1, characterized in that, when the branch is an isosceles triangle, the branch is an isosceles triangle structure or two triangles connected in series structure.