CN112216983A

CN112216983A - Luneberg lens antenna applied to S wave band

Info

Publication number: CN112216983A
Application number: CN202011309720.8A
Authority: CN
Inventors: 王宏庆; 姚丹; 戚泽超; 张祖球
Original assignee: Jiangsu Chenchuang Technology Co ltd
Current assignee: Jiangsu Chenchuang Technology Co ltd
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2021-01-12

Abstract

The invention provides a Luneberg lens antenna applied to S wave band, comprising a medium ball and a feed source array for realizing beam control and scanning capability, wherein the feed source array is uniformly arranged along the periphery of the medium ball, the medium ball adopts a layered structure, and the material of each layer of the medium ball comprises but is not limited to polystyrene, copper barium titanate and other high dielectric constant materials; the method can realize that the standing-wave ratio of the horn feed source at two cross polarization ports of 1.7GHz-2.7GHz is less than 1.5, and the isolation between the feed source ports is more than 30 dB. And after the dielectric lens is added, the beam width passing through the lens is obviously narrowed compared with the beam width of the feed source, so that the invention has higher gain, larger working bandwidth and better multi-beam coverage capability.

Description

Luneberg lens antenna applied to S wave band

Technical Field

The invention belongs to the technical field of antennas, and particularly relates to a Luneberg lens antenna applied to an S waveband.

Background

With the rapid development of satellite communication technology, many new and more stringent requirements are put on the ground station antenna. Such as the need for broadband, high gain, multi-beam, and wide scan angle characteristics. In addition, with the development of the digital satellite direct broadcast service, the demand of one line and multiple stars is urgent. In the traditional satellite communication, a parabolic antenna is mostly adopted to manufacture a ground station high-gain antenna, but with the upgrading of the satellite communication technology, especially in the aspect of the communication-in-motion technology of a mobile satellite communication system, the disadvantages of the parabolic antenna gradually emerge, for example, the focal position of the parabolic antenna is unique, and the performance of the antenna is greatly changed due to the slight change of the feed source position. This determines that each parabolic antenna can only transmit and receive communications to and from one satellite. In the case of multiple satellite communication, multiple parabolic antennas are required, which occupies a large space and increases the cost accordingly.

One of the applications of the luneberg lens is satellite communication, because of good radiation characteristics, many defects of a parabolic antenna are overcome, a single luneberg lens antenna can be used for communication of a plurality of satellites, is used for satellite news rebroadcasting vehicles, mobile satellite ground stations and the like, and is currently applied in many foreign countries. The second application of the luneberg lens is a passive reflector, which is used in an electronic interference system, the luneberg lens reflector is formed by adding a metal surface with a specific area on the surface of a dielectric sphere, and a unidirectional reflector and an omnidirectional reflector can be designed according to actual requirements. The reflector has a larger scattering cross section and a wider scattering width, the scattering cross section is theoretically 30 times larger than that of a corner reflector with the same size, and the reflector is mainly used for target identification of safe navigation, marine beacons, echo signal intensifiers, targets, false targets of electronic interference and the like. The luneberg lens can also be used in other applications, such as in automotive collision avoidance systems, where the beam scanning speed is fast, there is no need to move a bulky antenna body, which increases scanning efficiency and speed, and it is also less expensive than a phased array antenna. In recent years, deformed cylindrical luneberg lenses are more and more concerned by students, and the luneberg lens antenna has the advantages of high gain, low loss, small millimeter wave frequency band size and the like, and is suitable for being used in an automobile anti-collision radar system.

Although the luneberg lens can theoretically replace a parabolic antenna and a phased array antenna, the luneberg lens is not particularly widely applied in practical engineering, mainly because the manufacturing of the high-performance luneberg lens is difficult and the requirement on the processing precision of a dielectric material is high. In practical application, the small-size lens has small application significance, a plurality of feed sources cannot be used due to the fact that the small size is too small, and the large-size luneberg lens is difficult to use due to the fact that the size is relatively large, so that the sphere is too heavy and is difficult to fix, and the application of the conventional spherical luneberg lens is greatly limited due to the problems, particularly in airplanes and ships with limited space. In recent years, a new device is designed by utilizing an optical transformation principle, the appearance of the antenna can be changed, and the requirements of different occasions are met.

Disclosure of Invention

In view of the above, the present invention provides a luneberg lens antenna with higher gain, larger operating bandwidth, better multi-beam coverage and capable of being applied to S-band.

In order to achieve the purpose, the invention adopts the technical scheme that: a luneberg lens antenna applied to S wave band comprises a dielectric sphere and a feed source array for realizing beam control and scanning capability, wherein the feed source array is uniformly arranged along the periphery of the dielectric sphere, the dielectric sphere adopts a layered structure, and the material of each layer of the structure of the dielectric sphere comprises but is not limited to a mixture of high dielectric constant materials such as polystyrene, copper barium titanate and the like; the convergence effect of the medium ball on the feed source array wave beams is adjusted by optimizing the dielectric constant and the thickness of each layer of the medium ball;

the feed source array consists of N groups of horn feed sources which are uniformly distributed along the periphery of the dielectric sphere, each group of horn feed sources comprises a square waveguide, a square horn and two coaxial feed ports which are arranged on the square waveguide and are vertical to each other, the inner cavities of the square waveguide and the square horn are communicated, four ridge structures are jointly arranged inside the square waveguide and the square horn, inner cores of the two coaxial feed ports respectively extend into the square waveguide and are connected with the corresponding ridge structures, and the system gain can be improved by controlling the distance between the feed source array and the dielectric sphere; by controlling the angle between the horn feeds, the coverage of the system beam can be adjusted.

Furthermore, the four ridge structures are respectively arranged on the four inner side walls of the square waveguide and the square horn, every two ridge structures are distributed in one plane, and the two planes are mutually perpendicular.

Furthermore, two coaxial feed ports are respectively arranged on two side faces of the square waveguide, the two coaxial feed ports are vertically arranged in space, and the lengths of the two coaxial feed ports to the square waveguide face are different, so that cross polarization is realized and port isolation is improved.

Furthermore, the horn feed source is coaxial feed, and the characteristic impedance of the horn feed source is 50 ohms.

Further, the medium ball is spherical or hemispherical.

Compared with the prior art, the invention has the beneficial effects that: the invention can realize that the standing-wave ratio of the horn feed source at two cross polarization ports of 1.7GHz-2.7GHz is less than 1.5, and the isolation between the feed source ports is more than 30 dB. And after the dielectric lens is added, the beam width passing through the lens is obviously narrowed compared with the beam width of the feed source, so that the invention has higher gain, larger working bandwidth and better multi-beam covering capability, thereby being capable of meeting the requirements of different occasions.

Drawings

FIG. 1 is a schematic structural diagram of a Luneberg lens antenna applied to S-band according to the present invention;

FIG. 2 is a view of the structural perspective of a single horn feed of the present invention;

FIG. 3 is a schematic diagram of a layered structure of a media sphere;

FIG. 4 is a graph of standing wave coefficient versus frequency for a single horn feed of the present invention;

FIG. 5 is a graph of dual port isolation versus frequency for a single horn feed of the present invention;

FIG. 6 is a diagram of beam coverage for the present invention using four horn feeds without a dielectric sphere;

FIG. 7 is a graph showing the gain variation in the 1.7GHz-2.7GHz band using a single horn feed without a dielectric sphere according to the present invention;

FIG. 8 is a variation curve of beam width in the frequency band of 1.7GHz-2.7GHz when a single horn feed source is adopted but no dielectric sphere is provided;

FIG. 9 is a diagram of beam coverage with a dielectric sphere using four horn feeds in accordance with the present invention;

FIG. 10 is a graph showing the gain variation in the frequency band of 1.7GHz-2.7GHz with the use of four horn feeds and the presence of a dielectric sphere according to the present invention;

FIG. 11 is a wave beam width variation curve within a frequency band of 1.7GHz-2.7GHz when four horn feeds are adopted and a dielectric sphere is provided;

the labels in the figure are: 1. the device comprises a horn feed source, 2, a dielectric sphere, 3, a ridge structure, 4, a coaxial feed port, 5, a square waveguide and 6, and a square horn.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

A luneberg lens antenna applied to S wave band is disclosed in figure 1, which mainly comprises two parts of a feed source array and a medium ball 2, wherein the feed source array is uniformly distributed along the periphery of the medium ball to generate N groups of wide beams with different radiation directions, after being focused by the medium ball, the beams are narrowed, the gain is also improved, and then the beams are radiated out according to the original direction to realize long-distance and large-range energy coverage.

Fig. 2 is a schematic structural diagram of a single horn feed source 1 constituting a feed source array in the present invention, wherein each horn feed source 1 is composed of two coaxial feed ports 4 perpendicular to each other, a square waveguide 5 and a square horn 6, wherein four ridge structures 3 are commonly arranged inside the square waveguide 5 and the square horn 6, and inner cores of the two coaxial feed ports 4 respectively extend into the square waveguide and are connected with the corresponding ridge structures 3. Furthermore, the four ridge structures 3 are respectively arranged on four inner side walls of the square waveguide 5 and the square horn 6, every two ridge structures 3 are distributed in one plane, and the two planes are perpendicular to each other. The structure can further improve the isolation of two ports and expand the impedance bandwidth while realizing dual polarization.

FIG. 3 is a schematic diagram of a layered structure of a dielectric sphere 2, which generally has a number of layers ranging from 3 to 10, and a first layer of material having a dielectric constant DK₁The material of the Nth layer has a dielectric constant DK_NThe convergence effect of the medium ball on the feed source wave beams can be adjusted by optimizing the dielectric constant and the thickness of each layer of material. Each layer of the dielectric ball is made of high dielectric constant materials such as polystyrene and barium copper titanate.

Fig. 4 and 5 are graphs showing the variation of standing wave coefficient and port isolation with frequency when a single horn feed source is adopted, as shown in fig. 4, the standing wave ratio is lower than 1.5 in the frequency band of 1.7GHz-2.7GHz, which shows that the feed source impedance matching in the wide frequency band is better. In this structure, there are many parameters that affect impedance matching, and for example, by optimizing the structural parameters of the four ridges and the distance between the feed port and the edge of the square waveguide, an ideal standing wave characteristic can be obtained. Meanwhile, as shown in fig. 5, it can be seen that the isolation of the two dual-polarized ports is less than-30 dB, and the crosstalk is small.

Fig. 6 is a diagram of the beam coverage of the present invention using four horn feeds without a dielectric sphere, with a directional pattern sidelobe of about 18dB and a wide beam, as shown in fig. 6.

FIG. 7 is a graph showing the gain variation in the 1.7GHz-2.7GHz band using a single horn feed without a dielectric sphere according to the present invention; as shown in fig. 7, the gain of the horn feed increases substantially with increasing frequency, with a minimum gain of 8.25dB and a maximum gain of 11 dB.

FIG. 8 is a variation curve of beam width in the frequency band of 1.7GHz-2.7GHz when a single horn feed source is adopted but no dielectric sphere is provided; as shown in fig. 8, the beam width fluctuates greatly in the entire frequency band and shows a tendency to decrease. At 1.9GHz the beam is widest, up to 69.9 °, and at 2.7GHz the beam is narrowest, 54.7 °.

FIG. 9 is a diagram of beam coverage with a dielectric sphere using four horn feeds in accordance with the present invention; as can be seen from fig. 9, the directional pattern has a low sidelobe and a narrow beam, and the coverage of the beam can reach-60 °.

FIG. 10 is a graph showing the gain variation in the frequency band of 1.7GHz-2.7GHz with the use of four horn feeds and the presence of a dielectric sphere according to the present invention; as can be seen from fig. 10, the gain fluctuates to some extent in the whole frequency band, but the overall trend is still increasing, and the gain in the whole frequency band is greater than 16dB, the minimum is 17.5dB, and the maximum can reach 20.2 dB. Compared with a single feed source, the gain of the antenna is greatly improved, and is improved by about 9 dB.

FIG. 11 is a wave beam width variation curve within a frequency band of 1.7GHz-2.7GHz when four horn feeds are adopted and a dielectric sphere is provided; as shown in fig. 11, at 1.7GHz, the beam is widest, reaching 22.6 °; at 2.7GHz, the beam is narrowest, 14.9 °. The width of the beam is much narrower than that of the single feed source, and the medium ball has a good convergence effect on the beam.

In conclusion, the invention can realize that the standing-wave ratio of the horn feed source at two cross polarization ports of 1.7GHz-2.7GHz is less than 1.5, the isolation between the feed source ports is more than 30dB, and the beam width passing through the medium ball is obviously narrowed compared with the beam width of the feed source after the medium ball is added, so that the horn feed source has higher gain, larger working bandwidth and better multi-beam covering capability.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A luneberg lens antenna applied to S wave band comprises a medium ball and a feed source array for realizing beam control and scanning capability, and is characterized in that: the feed source arrays are uniformly arranged along the periphery of the dielectric sphere, the dielectric sphere adopts a layered structure, and the material of each layer of the dielectric sphere comprises but is not limited to a mixture of high dielectric constant materials such as polystyrene, barium copper titanate and the like; the convergence effect of the medium ball on the feed source array wave beams is adjusted by optimizing the dielectric constant and the thickness of each layer of the medium ball;

2. The luneberg lens antenna for S-band application as claimed in claim 1, wherein: the four ridge structures are respectively arranged on the four inner side walls of the square waveguide and the square horn, every two ridge structures are distributed in one plane, and the two planes are mutually vertical.

3. A luneberg lens antenna for S-band applications as claimed in claim 2, wherein: the two coaxial feed ports are respectively arranged on two side faces of the square waveguide and are vertically arranged in space, and the two coaxial feed ports are different from the square waveguide face in length so as to realize cross polarization and improve port isolation.

4. A luneberg lens antenna for S-band applications as claimed in claim 3, wherein: the horn feed source is coaxial feed and has a characteristic impedance of 50 ohms.

5. The luneberg lens antenna for S-band application as claimed in claim 1, wherein: the medium ball is spherical or hemispherical.