CN111525280A - Circularly polarized scanning array antenna based on Rotman lens - Google Patents

Abstract

The invention provides a circular polarization scanning array antenna based on Rotman lens, which includes: a phase shift network layer, a feeding network layer and an antenna array layer. The phase shift network layer includes: a feeding SMA joint 10 and a Rotman lens network, the feeding SMA joint 10 is electrically connected to the Rotman lens network; the feeding network layer includes: a feeding network 5 , to feed the antenna array layer; the antenna array layer includes: a plurality of patch antenna units 1 arranged in an array structure. The invention can form better circular polarization in the beam scanning direction, and realizes the circular polarization beam scanning of the array antenna.

Description

Circularly polarized scanning array antenna based on Rotman lens

technical field

The present invention relates to the field of antennas, in particular to a circularly polarized scanning array antenna based on a Rotman lens.

Background technique

With the rapid development of wireless communication technology, communication with mobile satellites is becoming more and more common as a common communication situation. Usually, the relative positions of the satellite and the vehicle, ship, etc. that communicate with it change all the time, so the communication antenna is required to have beam scanning capability. At the same time, the characteristic that the circularly polarized antenna can receive any polarized wave is very important for the mobile satellite communication where the position changes frequently, and the circularly polarized antenna can overcome the influence of the multipath effect to a certain extent.

After literature retrieval, John Huang published an article "A Technique for an Array to Generate CircularPolarization with Linearly Polarized Elements" in the journal IEEE Transactions on Antennas and Propagation in 1986, in which he proposed a method to obtain circular polarization by rotating a linearly polarized antenna. method, and designed the corresponding feeding network for experimental verification. This method is often used to improve the axial ratio and pattern symmetry of antenna arrays, and is widely used in the design of circularly polarized antennas. For example, the article "A Wideband Sequential-Phase FedCircularly Polarized Patch Array" published in IEEE Transactions on Antennas and Propagation "Circularly-Polarized Focused Microstrip AntennaArrays" published in the journal IEEE Antennas and WirelessPropagation Letters, etc., all apply the rotation technique on the basis of the circularly polarized antenna element to obtain better circularly polarized performance and more symmetrical pattern. However, all the above documents only consider the phase distribution that forms a rotation in the normal direction of the array, and the feeding network adopted is not suitable for the case of beam scanning. In a common array that implements circularly polarized beam scanning, the antenna unit is required to have a wide axial ratio beam width to ensure the axial ratio of the main lobe direction when the array is scanned at a large angle. In addition, due to the effect of coupling in the antenna array, the axial ratio of the beam width of the antenna element is inevitably narrowed. The article "Wide-Beam CircularlyPolarized Microstrip Magnetic-Electric Dipole Antenna for Wide-Angle ScanningPhased Array" published in the journal IEEE Antennas and Wireless Propagation Letters analyzes the variation of the axial ratio beamwidth of the antenna elements in the array. It can be seen that the axis of the antenna element in the array is narrower than the beam width, and it is difficult to achieve large-angle circularly polarized beam scanning.

SUMMARY OF THE INVENTION

In view of the defects in the prior art, the purpose of the present invention is to provide a circularly polarized scanning array antenna based on a Rotman lens.

A circularly polarized scanning array antenna based on a Rotman lens provided according to the present invention includes: a phase shift network layer, a feeding network layer and an antenna array layer;

The phase shift network layer includes: a feeding SMA joint 10 and a Rotman lens network, and the feeding SMA joint 10 is electrically connected to the Rotman lens network;

The feeding network layer includes: a feeding network 5, which feeds the antenna array layer;

The antenna array layer includes: a plurality of patch antenna units 1 arranged in an array structure;

Wherein, the feeding network 5 respectively connects the patch antenna units 1 in each row or each column to form a sub-array;

In the sub-array, the patch antenna elements 1 with odd bits have the same rotation angle and the same feeding phase, the patch antenna elements 1 with even bits have the same rotation angle and the same feeding phase, and the patch antenna elements 1 with odd and even bits have the same rotation angle and the same feeding phase. The phase difference is 90 degrees;

The phase difference between adjacent sub-arrays is 180 degrees.

Preferably, the feeding network 5 respectively connects the patch antenna units 1 in each row or column with odd-numbered patch antenna units 1, and connects the patch antenna units 1 in each row or column with even-numbered patch antenna units 1. The bit patch antenna units 1 are connected together.

Preferably, the feeding network 5 connects the adjacent odd-numbered patch antenna units 1 in a tree-like structure, and the feeding network 5 connects the adjacent even-numbered patch antenna units 1 in a tree-like structure. The structures are connected together in pairs.

Preferably, every four patch antenna units 1 arranged in a rectangle is a small matrix, the rotation angles of the four patch antenna units 1 in the small matrix are different from each other, and each patch antenna unit 1 is relatively in the small matrix. The adjacent patch antenna units 1 are rotated by 90 degrees, which are 270 degrees, 180 degrees, 90 degrees, and 0 degrees, respectively.

Preferably, the Rotman lens network comprises:

Rotman Lens Floor 7;

Rotman lens medium plate 8: arranged on the upper surface of the Rotman lens floor 7;

The Rotman lens 9 is arranged on the upper surface of the Rotman lens medium plate 8 .

Preferably, the feeding network layer further includes:

Upper-layer dielectric board 4: arranged on the upper side of the feeding network 5;

Lower-layer dielectric plate 6: arranged on the lower side of the feeding network 5;

The feeding network is formed by pressing the upper dielectric board 4 , the feeding network 5 and the lower dielectric board 6 .

Preferably, the upper dielectric board 4 and the lower dielectric board 6 comprise prepregs.

Preferably, the antenna array layer further includes:

Antenna dielectric board 2 : the patch antenna unit 1 is arranged on the antenna dielectric board 2 .

Preferably, the output ends of the Rotman lens network are respectively connected to the sub-arrays through equal-phase transmission lines.

Preferably, the Rotman lens network is a microstrip structure.

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

1. The present invention can realize the rotational phase distribution (270°, 180°, 90°, 0°) in the beam scanning direction, that is, realize circularly polarized beam scanning.

2. The present invention designs a new type of feeding network to realize the rotation phase.

3. The present invention realizes the low profile of the Rotman lens antenna through the multi-layer board lamination technology.

Description of drawings

Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is the top view of the antenna array of the present invention;

3 is a top view of a stripline feed network of the present invention;

Fig. 4 is the top view of the Rotman lens network of the present invention;

5-8 are schematic diagrams of the rotation phase of the present invention;

Fig. 9 is the output amplitude and phase distribution diagram of Rotman lens of the present invention;

Fig. 10 is the reflection coefficient and isolation diagram of the lens feeding end of the present invention;

Fig. 11 is the directional diagram when the different ports of the Rotman lens of the present invention are fed;

FIG. 12 shows the axial ratio and gain of the beam scanning to different directions according to the present invention.

In the figure: 1-SMD antenna unit, 2-Antenna dielectric board, 3-Antenna floor, 4-Upper dielectric board, 5-Feed network, 6-Lower dielectric board, 7-Rotman lens floor, 8-Road Terman lens dielectric plate, 9-Rotman lens, 10-feed SMA connector.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the inventive concept. These all belong to the protection scope of the present invention.

The present invention is applied to the field of communication technology, such as vehicle-mounted satellite communication and the like. The overall antenna is a planar structure, which is convenient to conform to the carrier. Different wave ports of the Rotman lens correspond to different beam directions, and the beam directions can be switched by switching the feed port of the Rotman lens.

As shown in FIGS. 1 to 4 , a circularly polarized scanning array antenna based on a Rotman lens provided by the present invention is a planar multi-layer structure as a whole. Electrical network layer and phase-shift network layer. Each layer is laminated through a prepreg, and the thickness of the entire antenna is 3.2mm. For the antenna array rotation technique, please refer to John Huang's paper "A Technique for an Array to Generate Circular Polarization with Linearly Polarized Elements", which gives the rotation rules for antenna elements and sub-arrays. Referring to Figure 3 and Figure 5-8 for the design of the feeding network, the feeding phase of each element in each row (or column) sub-array is obtained from Figure 5-8. Referring to FIG. 3 , a feed network can be designed to meet the rotational phase requirements, and the feed network is not limited to a stripline structure. For Rotman lens design, please refer to W.ROTMAN's paper "Wide-Angle Microwave Lens for Line Source Applications", which gives the design principle and implementation method of the lens.

The phase shift network layer includes: a feeding SMA joint 10 and a Rotman lens network, the feeding SMA joint 10 is electrically connected with the Rotman lens network. The Rotman lens network includes: a Rotman lens floor 7 , a Rotman lens dielectric plate 8 and a Rotman lens 9 . The Rotman lens medium plate 8 is arranged on the upper surface of the Rotman lens floor 7 , and the Rotman lens 9 is arranged on the upper surface of the Rotman lens medium plate 8 .

The feeding network layer includes: a feeding network 5 , an upper dielectric board 4 and a lower dielectric board 6 . The feeding network 5 feeds the antenna array layer, the upper dielectric plate 4 is arranged on the upper side of the feeding network 5, the lower dielectric plate 6 is arranged on the lower side of the feeding network 5, and the feeding network passes through the upper dielectric plate 4 and the feeding network. 5 and the lower dielectric plate 6 are pressed together.

The antenna array layer includes: a plurality of patch antenna units 1 and an antenna dielectric board 2 , and the patch antenna units 1 are arranged on the antenna dielectric board 2 . A plurality of patch antenna units 1 are arranged in an array structure. The patch antenna unit 1 may be a linearly polarized unit or a circularly polarized unit.

Wherein, the feeding network 5 respectively connects the patch antenna units 1 in each row or each column to form a sub-array. In the sub-array, the patch antenna elements 1 with odd bits have the same rotation angle and the same feed phase, the patch antenna elements 1 with even bits have the same rotation angle and the same feed phase, and the patch antenna elements 1 with odd and even bits have the same phase. The difference is 90 degrees. The phase difference between adjacent sub-arrays is 180 degrees. The Rotman lens network is a microstrip structure, and the output ends of the Rotman lens network are respectively connected to the sub-arrays through equal-phase transmission lines.

The feeding network 5 respectively connects the patch antenna units 1 of each row or column with the odd-numbered patch antenna units 1, and connects the patch antenna units 1 of each row or column with the even-numbered patch antenna units 1 together. . The feeding network 5 connects the adjacent odd-numbered patch antenna units 1 together in a tree-like structure, and the feeding network 5 connects the adjacent even-numbered patch antenna units 1 together in a tree-like structure. Every four patch antenna units 1 arranged in a rectangle is a small matrix. The rotation angles of the four patch antenna units 1 in the small matrix are different. Each patch antenna unit 1 is relatively adjacent to the patches in the small matrix. The antenna unit 1 is rotated by 90 degrees, respectively 270 degrees, 180 degrees, 90 degrees, and 0 degrees.

The present invention realizes the working principle of circularly polarized beam scanning as follows:

Figure 5 shows a circularly polarized antenna array using rotating technology, which was first proposed by John Huang in the article "A Technique for an Array to Generate Circular Polarization with Linearly Polarized Elements" published in IEEE Trans. Antennas Propag. in 1986. In the rotation technology, every 4 units form a sub-array, each unit is rotated 90° relative to the previous unit, and the sub-array is also rotated 90° relative to the previous sub-array. The array obtained by this method can obtain better circular polarization performance, and the corresponding commonly used feeding networks are shown in Figure 6. These two networks can form a rotated phase distribution in the normal direction of the antenna array, so as to obtain better circular polarization performance in the normal direction. However, since the phase between antenna elements cannot be adjusted, it is not suitable for beam scanning.

Fig. 7 shows the circularly polarized antenna array feeding network suitable for beam scanning proposed by the present invention, and Fig. 5(b) is obtained by adding the element feeding phase in Fig. 5(a) and the feeding phase of the sub-array in the feed phase. It can be seen that, for a single row (or column), odd-numbered (or even-numbered) cells have the same handedness and the same feeding phase. Therefore, a new feed network in Fig. 7 is proposed. The network uses a single row (or column) as a sub-array, connects odd-numbered cells and even-numbered cells respectively, and adds a 90° phase difference between odd- and even-numbered cells, so that the sub-array forms circular polarization. In order to meet the phase distribution of the rotation technology, a phase difference of 180° needs to be added between the sub-arrays. Figure 8 shows the phase distribution on the isophase plane when the beam is scanned. It can be seen that after adopting the proposed feeding network, the phase difference between the sub-arrays can be adjusted arbitrarily, so the beam can be directed to any direction. At the same time, on the isophase plane, the phase still meets the requirements of the rotational phase. Therefore, the network is suitable for circularly polarized beam scanning.

In order to realize beam scanning, the present invention adopts a Rotman lens to provide the phase difference required for beam scanning. As shown in Figure 1, the Rotman lens generates the phase difference required for sub-array scanning, and then the designed sub-array provides the rotated phase distribution. It realizes the formation of rotating phase distribution on the phase plane of the scanned beam.

Figure 9 shows the output amplitude and phase of the Rotman lens. It can be seen that the Rotman lens can provide the amplitude and phase difference required for beam scanning.

Figure 10 shows the reflection coefficient of the input port of the Rotman lens and the isolation of wave port 1 and other wave ports. The reflection coefficient and isolation are both less than -10dB.

Figure 11 shows the simulation results of beam scanning. It can be seen that the beam scanning range reaches ±44°.

Figure 12 shows the axial ratio and gain during beam scanning. It can be seen that the axial ratio in the beam scanning direction is less than 3dB.

In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying the indicated device. Or elements must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the present application.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essential content of the present invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily, provided that there is no conflict.

Claims (10)

1. A circularly polarized scanning array antenna based on a rotman lens, comprising: the antenna comprises a phase shift network layer, a feed network layer and an antenna array layer;

the phase shift network layer includes: a power feed SMA connector (10) and a Rotman lens network, wherein the power feed SMA connector (10) is electrically connected with the Rotman lens network;

the feed network layer includes: a feed network (5) for feeding the antenna array layer;

the antenna array layer includes: a plurality of patch antenna units (1) arranged in an array structure;

the feed network (5) connects the patch antenna units (1) of each row or each column to form a sub-array;

in the subarray, the odd-number patch antenna units (1) have the same rotation angle and the same feed phase, the even-number patch antenna units (1) have the same rotation angle and the same feed phase, and the phase difference of the odd-number patch antenna units (1) is 90 degrees;

the phase difference between adjacent sub-arrays is 180 degrees.

2. The circularly polarized scanning array antenna based on a rotman lens according to claim 1, characterized in that the feeding network (5) connects together the odd-numbered patch antenna elements (1) of the patch antenna elements (1) of each row or each column and connects together the even-numbered patch antenna elements (1) of the patch antenna elements (1) of each row or each column, respectively.

3. The circularly polarized scanning array antenna based on the rotman lens as claimed in claim 2, wherein the feeding network (5) connects two adjacent odd-numbered patch antenna units (1) in a tree structure, and the feeding network (5) connects two adjacent even-numbered patch antenna units (1) in a tree structure.

4. The circularly polarized scanning array antenna based on the rotman lens as claimed in claim 1, wherein every four patch antenna units (1) in the rectangular arrangement are a small matrix, the rotation angles of the four patch antenna units (1) in the small matrix are different, and each patch antenna unit (1) is rotated 90 degrees, 270 degrees, 180 degrees, 90 degrees and 0 degrees, respectively, relative to the adjacent patch antenna unit (1) in the small matrix.

5. The rotman lens based circularly polarized scanning array antenna of claim 1, wherein the rotman lens network comprises:

a Rotman lens floor (7);

rotman lens dielectric plate (8): is arranged on the upper surface of the Rotman lens floor (7);

and the Rotman lens (9) is arranged on the upper surface of the Rotman lens dielectric plate (8).

6. The rotman lens based circularly polarized scanning array antenna of claim 1, wherein the feed network layer further comprises:

upper dielectric sheet (4): the power supply network is arranged on the upper side of the feed network (5);

lower dielectric plate (6): the power supply network is arranged at the lower side of the feed network (5);

the feed network is formed by pressing the upper dielectric plate (4), the feed network (5) and the lower dielectric plate (6).

7. The circularly polarized scan array antenna based on a rotman lens of claim 6, wherein the upper dielectric plate (4) and the lower dielectric plate (6) comprise a prepreg.

8. The rotman lens based circularly polarized scanning array antenna of claim 1, wherein the antenna array layer further comprises:

antenna dielectric plate (2): the patch antenna unit (1) is arranged on the antenna dielectric plate (2).

9. The circularly polarized scan array antenna based on a rotman lens of claim 1, wherein the output terminals of the rotman lens network are respectively connected to the sub-arrays through equal phase transmission lines.

10. The circularly polarized scan array antenna based on a rotman lens of claim 1, wherein the rotman lens network is a microstrip structure.

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