阅读说明：本技术 一种卡塞格伦天线 (Cassegrain antenna ) 是由 刘可 于 2019-09-09 设计创作，主要内容包括：一种卡塞格伦天线,包括馈源天线(11)、主反射面(13)和副反射面以及主副反射面固定装置(14)；所述馈源天线(11)为喇叭天线中的圆锥喇叭,主反射面(13)采用抛物面的形式,所述副反射面用频率选择表面(15)来取代,该频率选择表面能够在8-14.5GHz和29-34GHz频点处产生谐振,使该频点处的电磁波表现为透射,产生较宽的辐射方向图,而在其他频点处则表现为反射,方向图较窄,对动中通系统的性能提高很大,天线为双频工作,其工作频带分别为8-14.5GHz和29-34GHz,在两个工作频带内,其方向图分别包含一个波束较窄和波束较宽的辐射方向图,能够很好的应用于动中通天线系统。(Cassegrain antenna, including feed antenna (11), main reflection plane (13) and the sub reflection plane and the main and sub reflection plane fixing device (14), the feed antenna (11) is the cone horn in the horn antenna, the main reflection plane (13) adopts the paraboloid form, the sub reflection plane is replaced by the frequency selective surface (15), the frequency selective surface can produce the resonance at the 8-14.5GHz and 29-34GHz frequency point, make the electromagnetic wave at the frequency point present the transmission, produce the broad radiation pattern, and present the reflection at other frequency points, the pattern is narrower, the performance improvement to the communication-in-motion system is very big, the antenna is dual-frequency working, its operating frequency band is 8-14.5GHz and 29-34GHz respectively, in two operating frequency bands, its pattern contains radiation pattern with narrower wave beam and wider wave beam respectively, can be well applied to the communication-in-motion antenna system.)

The Cassegrain antenna comprises a feed source antenna (11), a main reflecting surface (13), an auxiliary reflecting surface (12) and a main and auxiliary reflecting surface fixing device (14), wherein the feed source antenna (11) is a conical horn in the horn antenna, and the main reflecting surface (13) is in a paraboloid form, and the Cassegrain antenna is characterized in that the auxiliary reflecting surface (12) is replaced by a frequency selection surface (15), and the frequency selection surface can generate resonance at frequency points of 8-14.5GHz and 29-34GHz, so that electromagnetic waves at the frequency points are represented as transmission to generate a wider radiation pattern, and the electromagnetic waves at other frequency points are represented as reflection to form a narrower pattern.

2. Cassegrain antenna according to claim 1, characterized in that in the center of the frequency selective surface (15) square holes with a side length of 4-7mm are made.

3. Cassegrain antenna according to claim 1, characterized in that the frequency selective surface (15) is in two pieces, placed in a mutually inclined manner.

4. Cassegrain antenna according to claim 1, 2 or 3, characterized in that the frequency selective surface (15) is five-layer structures which are formed as a periodic structure of cells, each cell being a square with a side length of 3mm, the -th layer (151) being a "loop" structure made of copper with a thickness of 0.017mm, the outer side of the outer frame being 2.85mm and the inner side being 2.35mm, the outer side of the inner frame being 1.85mm and the side length being 1.35mm, the second layer (152) being a dielectric material with a dielectric constant of 2.65, the thickness being 1mm and the shape being a square with a side length of 3mm, the third layer (153) being a "mouth" shaped metal frame with a side length of 3mm and the inner side being 2.2mm, the fourth layer being of the same structure as the second layer (152), the fifth layer being of the same structure as the -th layer (151) and the frequency selective surface being 8 x 8 cells.

5. Cassegrain antenna according to claim 3, characterized in that the frequency selective surface (16) is formed by two 8 x 4 elements in a tilted group at an angle of 8-12 °.

6. A cassegrain antenna according to claim 1, 2 or 3 characterised in that the conical horn is a hollow cone with a base radius of 10mm and a height of 8-10mm, followed by a circular tube waveguide of radius 8mm for feeding.

7. Cassegrain antenna according to claim 1 or 2, characterized in that the hyperbolic equation of the secondary reflecting surface (12) is:

8. Cassegrain antenna according to claim 1, 2 or 3, characterized in that the parabolic equation of the main reflector (13) is: y is²＝4f_mx, the paraboloid is formed by rotating a parabola around an x axis, and the diameter of the mouth surface is 130-180 mm.

9. Cassegrain antenna according to claim 1, 2 or 3, characterized in that the main reflecting surface (13) and the auxiliary reflecting surface (12) are connected to the fixing means (14) by three support rods, each of which is a metal rod with a radius of 0.5-1.5mm, connecting the edges of the main reflecting surface (13) and the auxiliary reflecting surface (12).

Technical Field

The invention relates to antennae.

Background

The so-called communication-in-motion system is a short term of a mobile satellite ground station communication system, and is specifically realized in the form of uninterrupted communication of vehicles, ships, airplanes and the like in motion, in the process, a communication-in-motion antenna needs to point to the direction of a satellite in real time, a servo system is needed to realize the process, the communication-in-motion antenna needs to have a narrow beam width and a large gain, and the cassegrain antenna is types of cassegrain antennas which can well meet the requirements.

Disclosure of Invention

In view of the above prior art, the technical problem to be solved by the present invention is to provide cassegrain antennas capable of generating wider beam width.

In order to solve the technical problem, the invention provides an Cassegrain antenna, which comprises a feed source antenna, a main reflecting surface, an auxiliary reflecting surface and a main and auxiliary reflecting surface fixing device, wherein the feed source antenna is a conical horn in the horn antenna, the main reflecting surface is in a paraboloid form, the auxiliary reflecting surface is replaced by a frequency selection surface, and the frequency selection surface can generate resonance at frequency points of 8-14.5GHz and 29-34GHz, so that electromagnetic waves at the frequency points are represented as transmission to generate wider beam width, and the electromagnetic waves at other frequency points are represented as reflection to generate narrower directional diagram.

As a further improvement , square holes with the side length of about 2 times of the operating wavelength and the size of 4-7mm are opened at the center of the frequency selection surface, the opening design has no great influence on the reflection and transmission characteristics of the antenna, but the reduction of the reflection at the center of the frequency selection surface can well improve the standing wave characteristics of the antenna.

As a further improvement of the present invention, the frequency selective surface is two pieces, disposed in a mutually inclined manner.

As a further improvement of steps of the present invention, the frequency selective surface is a five-layer structure , which is a periodic structure formed by unit cells, each unit is a square with a side length of 3mm, the th layer is a zigzag structure made of copper with a thickness of 0.017mm, the outside side length of the outer frame is 2.85mm, the inside side length is 2.35mm, the outside side length of the inner frame is 1.85mm, the measured side length is 1.35mm, the second layer is a dielectric material with a dielectric constant of 2.65, the thickness is 1mm, the shape is a square with a side length of 3mm, the third layer is a metal frame shaped like a Chinese character 'kou', the outside side length is 3mm, the inside side length is 2.2mm, the fourth layer is the same structure as the second layer, the fifth layer is the same structure as the th layer, the frequency selective surface is composed of 8 × 8 units, the frequency selective surface can generate resonance on the surface of the material in some frequency bands, so that the electromagnetic waves in specific frequency bands can transmit, while the electromagnetic waves in other frequency bands are reflected by the antenna card, and the antenna has a great reflection characteristic of the antenna card, which is increased in the frequency band.

As a further improvement of , the frequency selective surface is formed by two 8 × 4 unit chips in an inclined angle group, the inclined angle is 8-12 degrees, so that the incident angle of electromagnetic waves has fixed change, but the influence on the transmission characteristic is small, the reflection characteristic changes due to the change of the angle, the direction of the reflected waves is changed, the reflected waves received by the feed source antenna are small, the standing wave characteristic is effectively improved, the working frequency band of the antenna is wide, the gain is high, the beam is narrow, and the antenna can be widely applied to satellite communication through .

As the improvement of , the conical horn adopts a hollow cone with the radius of the bottom edge of 10mm and the height of 8-10mm, and then is connected with a circular tube waveguide with the radius of 8mm for feeding, so that the antenna has the advantages of simple structure, simple feeding mode, moderate beam width, capability of well utilizing a reflecting surface at a proper distance, gradually-expanded waveguide ports in structure and strong directivity.

As a further improvement of , the hyperbolic equation of the secondary reflecting surface is:

the hyperboloid is formed by rotating the hyperboloid around the x axis, the diameter of the mouth surface is 8-12mm in order to avoid diffraction and shielding as small as possible, the hyperboloid is in the form of hyperboloid, the hyperboloid has electromagnetic waves radiated from focuses, and the electromagnetic waves are reflected by the hyperboloid and are equivalent to the electromagnetic waves directly radiated from another focuses of the hyperboloid, so that the purpose of directly radiating the electromagnetic waves from the focus of the main reflecting surface can be achieved by only coinciding focuses of the hyperboloid with the focus of the main reflecting surface and arranging the feed source antenna on another focuses of the feed source antenna, namely, the hyperboloid directlyMagnetic wave -like effect.

As a further improvement of , the parabolic equation of the main reflecting surface is y²＝4f_mAnd x, the paraboloid is formed by rotating a parabola around an x axis, the diameter of the mouth surface is 130-180mm in consideration of the whole size and the working efficiency of the antenna, the paraboloid is adopted, the focusing characteristic of the parabola is mainly applied, the energy of the Cassegrain antenna is converged at the focus of the paraboloid, and the radiation energy of the measured target is enhanced.

As a further improvement of , the main reflecting surface and the auxiliary reflecting surface connecting and fixing device adopts three supporting rods to connect the edges of the main reflecting surface and the auxiliary reflecting surface, and the supporting rods adopt metal rods with the radius of 0.5-1.5mm, so that the invention has the characteristics of small shielding and light weight.

Drawings

Embodiments of the present invention are described in further detail with reference to the drawings, in which:

FIG. 1 is a conventional Cassegrain antenna structure;

FIG. 2 is a modified subreflector;

FIG. 3 shows a modified subreflector th, five layers;

FIG. 4 shows a second, fourth layer of the improved subreflector;

FIG. 5 is a third layer of the improved subreflector;

FIG. 6 is an apertured sub-reflector;

FIG. 7 is a wedge shaped subreflector;

FIG. 8 is a modified Cassegrain antenna;

FIG. 9 is a diagram of the return loss of a modified Cassegrain antenna;

FIG. 10 is a modified Cassegrain antenna pattern (9 GHz);

FIG. 11 is a modified Cassegrain antenna pattern (13.5 GHz);

FIG. 12 is a modified Cassegrain antenna pattern (29 GHz);

FIG. 13 is a modified Cassegrain antenna pattern (32 GHz);

FIG. 14 shows the return loss of the improved Cassegrain antenna with the opening of the sub-reflecting surface (a square hole with a side length of 2.5 mm);

FIG. 15 shows the return loss of the improved Cassegrain antenna with the opening-shaped sub-reflecting surface (4 mm square hole);

FIG. 16 shows the return loss of the improved Cassegrain antenna with the opening-shaped sub-reflecting surface (5 mm square hole on side);

FIG. 17 is a diagram of an improved Cassegrain antenna pattern (11GHz) with the subreflector being an aperture;

FIG. 18 is a diagram of an improved Cassegrain antenna pattern (31GHz) with the subreflector in the form of an opening (a square hole with 2.5mm side length);

FIG. 19 is a diagram of an improved Cassegrain antenna pattern (31GHz) with the subreflector in the form of an opening (a 4mm square hole on a side);

FIG. 20 is a diagram of an improved Cassegrain antenna pattern (31GHz) with the subreflector in the form of an opening (a square hole 5mm on a side);

FIG. 21 shows the return loss of the improved Cassegrain antenna with the subreflector in the form of a wedge (8 degree of inclination);

FIG. 22 shows the return loss of the improved Cassegrain antenna with the subreflector in the form of a wedge (with an inclination angle of 12 °);

FIG. 23 shows return loss of a modified Cassegrain antenna with a wedge-shaped secondary reflector (13 degree of inclination);

FIG. 24 is a diagram of a modified Cassegrain antenna pattern (11GHz) with subreflector in the form of a wedge;

FIG. 25 is a diagram of a modified Cassegrain antenna pattern (31GHz) with subreflector in the form of a wedge (8 DEG tilt);

FIG. 26 is a diagram of a modified Cassegrain antenna pattern (31GHz) with subreflector in the form of a wedge (12 DEG tilt);

FIG. 27 is a modified Cassegrain antenna pattern (31GHz) with subreflector in the form of a wedge (13 ° tilt);

Detailed Description

Cassegrain antenna, including feed source antenna 11, main reflection surface 13 and sub reflection surface 12 and main and sub reflection surface fixing device 14, the feed source antenna 11 is a conical horn in the horn antenna, the main reflection surface 13 adopts the paraboloid form, the sub reflection surface 12 is replaced by the frequency selective surface 15, the frequency selective surface can produce resonance at the frequency point of 8-14.5GHz and 29-34GHz, make the electromagnetic wave at the frequency point appear as transmission, produce the broad beam width, and appear as reflection at other frequency points, the directional diagram is narrower, as shown in fig. 1, 8, adopt this kind of scheme to the performance improvement of the communication-in-the-motion system very much.

As a further improvement of , square holes with side length of about 2 times of the operating wavelength and 4-7mm are opened at the center of the frequency selective surface 15, and the opening design has no great influence on the reflection and transmission characteristics of the antenna, but the reduction of reflection at the center of the frequency selective surface can well improve the standing wave characteristics of the antenna, as shown in fig. 6.

As a further improvement of the present invention, the frequency selective surface 15 is two pieces, disposed in a mutually inclined manner.

As a further improvement of steps of the present invention, the frequency selective surface 15 is a five-layer structure, which is configured as a periodic structure composed of unit cells, each unit cell is a square with a side length of 3mm, the th layer 151 is a zigzag structure made of copper with a thickness of 0.017mm, the outer side of the outer frame is 2.85mm and the inner side is 2.35mm, the outer side of the inner frame is 1.85mm and the measured side is 1.35mm, the second layer 152 is a dielectric material with a dielectric constant of 2.65, the thickness is 1mm and the shape is a square with a side length of 3mm, the third layer 153 is a zigzag metal frame with an outer side of 3mm and an inner side of 2.2mm, the fourth layer is the same structure as the second layer 152, the fifth layer is the same structure as the th layer 151, the frequency selective surface is composed of 8 × 8 unit cells, the frequency selective surface can generate resonance on the surface of the material in some frequency bands, so that the transmission of the specific frequency bands can be realized, and the transmission characteristics of other antenna can be greatly improved according to the frequency bands of the antenna, which is shown in the electromagnetic wave transformation graph of the antenna, and the antenna, such as the antenna, the antenna is designed and the antenna, and the antenna is represented by the antenna, and the antenna is represented by the electromagnetic wave transformation graph.

As a further improvement of , the frequency selective surface 16 is formed by two 8 × 4 unit chips in an inclined angle group, the inclined angle is 8-12 °, so that the incident angle of the electromagnetic wave has a fixed change of , but the influence on the transmission characteristic is small, the reflection characteristic changes due to the change of the angle, the direction of the reflected wave is changed, the reflected wave received by the feed antenna is small, the standing wave characteristic is effectively improved, the operating frequency band of the antenna is wide, the gain is high, the beam is narrow, and the antenna can be widely applied to satellite communication by , as shown in fig. 7.

As the improvement of , the conical horn adopts a hollow cone with the radius of the bottom edge of 10mm and the height of 8-10mm, and then is connected with a circular tube waveguide with the radius of 8mm for feeding, so that the antenna has the advantages of simple structure, simple feeding mode, moderate beam width, capability of well utilizing a reflecting surface at a proper distance, gradually-expanded waveguide ports in structure and strong directivity.

As a further improvement of , the hyperbolic equation of the secondary reflecting surface 12 is:

the hyperboloid is formed by rotating the hyperboloid around an x axis, the diameter of an opening surface is 8-12mm in order to avoid diffraction and shielding as small as possible, the hyperboloid is in the form of a hyperboloid, the hyperboloid has electromagnetic waves radiated from focuses, and the electromagnetic waves are reflected by the hyperboloid and are equivalent to the characteristics of electromagnetic waves directly radiated from another focuses of the hyperboloid, so that the effect of directly radiating the electromagnetic waves from the focus of the main reflecting surface 13 can be achieved only by superposing focuses of the hyperboloid 12 with the focus of the main reflecting surface 13 and arranging the feed source antenna 11 on another focuses of the feed source antenna.

As a further improvement of , the parabolic equation of the main reflecting surface 13 is y²＝4f_mAnd x, the paraboloid is formed by rotating a parabola around an x axis, the diameter of the mouth surface is 130-180mm in consideration of the whole size and the working efficiency of the antenna, the paraboloid is adopted, the focusing characteristic of the parabola is mainly applied, the energy of the Cassegrain antenna is converged at the focus of the paraboloid, and the radiation energy of the measured target is enhanced.

As a further improvement , the main reflecting surface 13 and the sub-reflecting surface 12 are connected by three supporting rods 14, the supporting rods are metal rods with the radius of 0.5-1.5mm, and the main reflecting surface 13 and the sub-reflecting surface 12 are connected by three supporting rods, so that the invention has the characteristics of small shielding and light weight.