CN113193384B - An array antenna - Google Patents

Abstract

The invention discloses an array antenna, which sequentially comprises a ground layer, a medium base layer, a patch antenna array and a parasitic ring arranged on the periphery of the patch antenna array. The medium plate layer comprises an air supporting layer and a medium substrate which are sequentially arranged from bottom to top, the patch antenna array is composed of 16 antenna units of 4 multiplied by 4, the patch antenna array is arranged on the medium plate layer, the feed network is printed on the medium plate layer, and ports of the antenna units are connected with the feed network. The patch antenna array is an antenna area array formed by four 1x4 antenna linear arrays, the 1x4 antenna linear arrays are formed by connecting four antenna units in series through the feed network, and the four 1x4 antenna linear arrays are connected in parallel by a main feeder of the feed network. The array antenna provided by the invention has high gain, low sidelobe and wide bandwidth, so that high-efficiency transmission of microwave wireless energy transmission is realized, the requirement of wireless energy transmission is met, the structural complexity is reduced, the loss is reduced, and the array antenna has a good application prospect.

Description

An array antenna

technical field

The invention relates to the field of microwave wireless energy transmission, in particular to an array antenna.

Background technique

As early as the 1970s, people proposed the concept of a solar space power station based on microwave energy transmission technology. In the field of solar space power stations, a lot of research has been done abroad. Compared with traditional energy transmission methods, microwave energy transmission technology has its unique advantages, such as no transmission medium, fast speed and low loss, and easy re-layout. Microwave energy transmission can also be used in wireless power distribution systems in buildings and cars and aircraft charged by microwaves. Microstrip antenna, as a new type of antenna successfully researched in the 1970s, has the advantages of simple structure, light weight, low profile, easy conformal installation with the surface of the aircraft, and integration with microstrip circuits. , aerospace, electronic countermeasures and radar and other fields have been widely used. Antenna gain is used to measure the ability of the antenna to send and receive signals in a specific direction. It is one of the most important parameters for selecting a microwave wireless energy transmission antenna. Band antenna usually only has a bandwidth of (0.7%-5%), because of its low gain, narrow frequency band and other defects, which limit its application range.

In order to improve the transmission efficiency of the microwave wireless energy transmission system, people have tried various methods to optimize the transmitting antenna array to improve the efficiency, performance and stability of the microwave energy transmission system. Therefore, for low cost, high gain, wide bandwidth and low The demand for millimeter-wave antennas or array antennas with lobes is increasing.

Therefore, it is necessary to provide an array antenna for solving the above problems.

Contents of the invention

The technical problem to be solved by the present invention is to provide an array antenna aimed at increasing the gain, reducing the sidelobe and widening the bandwidth in order to realize high-efficiency transmission of microwave wireless energy transmission.

The technical solution adopted by the present invention to solve technical problems is as follows:

An array antenna, which sequentially includes a ground layer and a dielectric base layer, a patch antenna array, and a parasitic loop arranged around the patch antenna array, and the dielectric base layer includes an air support layer and a dielectric substrate sequentially arranged from bottom to top , the patch antenna array is composed of 16 antenna units of 4×4, the patch antenna array is arranged on the dielectric board layer, and a feeding network is printed on the dielectric board layer, and the antenna unit’s The ports are connected to the feed network.

In an implementation manner, preferably, the patch antenna array is an antenna plane array composed of four 1×4 antenna line arrays, and the 1×4 antenna line array consists of four antenna units passing through the The feed network is arranged in series, and the four 1×4 antenna arrays are connected by the main feeder lines of the feed network to form a parallel arrangement.

In one implementation, preferably, the feed network includes a quarter-wavelength impedance transformation section and a T-shaped power splitter, and the main feeder has the same resistance as the quarter-wavelength impedance transformation section .

In an implementation manner, preferably, the ground layer is a metal copper layer.

In an implementation manner, preferably, the air supporting layer is a hollowed-out substrate as a supporting frame, and the hollowed-out treatment is carried out in a hollowed-out design corresponding to the feed network and the patch antenna array.

In an implementation manner, preferably, the dielectric substrate is a substrate made of Rogers Ro4350 high-frequency material.

In an implementation manner, preferably, the ground layer, the air support layer, and the dielectric substrate are all provided with small holes correspondingly, and the small holes are used for pressing the dielectric plate layer.

In an implementation manner, preferably, the patch antenna array and the parasitic loop are on the same plane, and have the same thickness and material.

In an implementation manner, preferably, the array antenna further includes a power dividing and combining component connected to the feeding network, and the power dividing and combining component is used to distribute the excitation amplitude to the ports according to a preset ratio , to achieve unequal amplitude feed.

Beneficial effects: the array antenna provided by the present invention is provided by setting a patch antenna array composed of 16 antenna elements of 4×4, and setting a parasitic loop around the patch antenna array, and the array antenna includes sequentially arranged from bottom to top The ground layer, the air support layer and the dielectric substrate, the mixed dielectric substrate and the parasitic ring jointly realize the broadband and high gain and effectively improve the impedance matching of the antenna, so that the working bandwidth of the array antenna is significantly greater than that of the ordinary single-layer microstrip antenna Bandwidth, the patch antenna array and the parasitic loop can increase the gain of the array antenna, and then obtain an array antenna with high gain, low sidelobe and wide bandwidth, which meets the needs of wireless energy transmission, reduces structural complexity, and reduces Loss, has a good application prospect.

Description of drawings

Fig. 1 is a schematic structural diagram of an array antenna provided by the present invention;

Fig. 2 is a schematic diagram of an exploded structure of an array antenna provided by the present invention;

Fig. 3 is the schematic diagram of the feed network structure of 1 * 4 antenna line array provided by the present invention;

Fig. 4 is the schematic diagram of the backbone feeder network structure that four 1x4 line arrays are connected together provided by the present invention;

Fig. 5 is a structural schematic diagram of a traditional microstrip array antenna;

Fig. 6 is the S11 simulation comparison diagram of the array antenna provided by the present invention and the microstrip array antenna provided in Fig. 5;

Fig. 7 is a comparison diagram of the E-plane simulation pattern change of the array antenna provided by the present invention and the microstrip array antenna provided in Fig. 5;

FIG. 8 is a comparison diagram of changes in H-plane simulation pattern between the array antenna provided by the present invention and the microstrip array antenna provided in FIG. 5 .

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer and clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer " and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, are constructed and operate in a particular orientation and therefore are not to be construed as limitations on embodiments of the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a A detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediary, and it may be an internal communication between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present invention in specific situations.

In order to overcome the above-mentioned problems in the prior art, the present invention provides an array antenna 100 . Please refer to Fig. 1-Fig. 4 at the same time, Fig. 1 is the structure schematic diagram of the array antenna provided by the present invention, Fig. 2 is the exploded structure schematic diagram of the array antenna provided by the present invention, Fig. 3 is the 1 * 4 antenna line array provided by the present invention A schematic diagram of the feeder network structure, FIG. 4 is a schematic diagram of the backbone feeder network structure connecting four 1x4 line arrays provided by the present invention.

The array antenna 100 sequentially includes a dielectric plate layer 10 , a patch antenna array (Copper) 20 , a feeding network 30 and a parasitic ring (Copper Ring) 40 disposed around the patch antenna array 20 . Specifically, the patch antenna array 20 is composed of 16 antenna units of 4×4, the patch antenna array 20 is arranged on the dielectric board layer 10, and the feed network 30 is printed on the dielectric board On layer 10 , the port of the antenna unit 21 is connected to the feeding network 30 .

Further, the array antenna 100 includes a ground layer 11 , an air support layer (Air) 12 and a dielectric substrate (Substrate) 13 arranged in sequence from bottom to top. The ground layer 11 is a metal copper layer, which supports the normal operation of the array antenna. The air supporting layer 12 is a hollowed-out substrate as a supporting frame, and the hollowed-out design is carried out corresponding to the feed network and the patch antenna array. Since the air layer cannot support other structures, in the present invention, a hollowed-out substrate of RogersRO4350 ( _εr =3.66, tanδ=0.001) material is set as a support frame, and its thickness h is 0.762mm. In order to meet the introduction requirements of the air layer, the present invention The provided air supporting layer 12 is hollowed out of the Rogers RO4350 at the lower part corresponding to the feeding network 30 and the patch antenna array 20 to obtain the air supporting layer provided by the present invention. The dielectric substrate 13 is a substrate made of Rogers Ro4350 high-frequency material, and its thickness h is also 0.762 mm. The thickness of the dielectric substrate 13 is much smaller than the wavelength, and the thin metal layer at the bottom of the dielectric substrate 13 is in contact with the ground layer 11 .

Among them, Rogers RO4350 high-frequency material is a glass fiber reinforced (non-PTFE) hydrocarbon/ceramic laminate designed for high-volume, high-performance commercial applications. The RO4350 is designed to provide excellent RF performance and cost-effective circuit production. The result is a low-loss material that can be produced at competitive prices using standard epoxy/glass (FR4) processes. As operating frequencies increase to 500MHz or higher, designers typically have significantly fewer laminate options to choose from. The RO4350PCB has the features required by RF microwave developers to enable repeatable designs of filters, coupling networks, and impedance-controlled transmission lines. Low dielectric loss allows the use of RO4350 series materials in many applications where higher operating frequencies limit the use of laminates for traditional printed circuit boards. The temperature coefficient of the dielectric constant is one of the lowest of all printed circuits, and the dielectric constant is stable over a wide frequency range which makes it an ideal substrate for broadband applications.

Specifically, the patch antenna array 20 provided by the present invention is an antenna plane array composed of four 1×4 antenna line arrays, and the 1×4 antenna line array is fed by four antenna units through the feed The network is arranged in series, and the four 1×4 antenna arrays are connected by the main feeder line of the feeding network 30 to form a parallel arrangement, thereby obtaining a 4×4 patch antenna array 20 composed of 16 antenna elements. Wherein, the 1×4 antenna line arrays are arranged in series and four of the 1×4 antenna line arrays are arranged in parallel, and the advantages of both series and parallel feeds are combined through a feeding mode combining series and parallel. Specifically, the patch antenna array 20 is disposed on the dielectric substrate 13, and the feeding network 30 is printed on the dielectric substrate 13 and correspondingly connected to the patch antenna array.

The feed network 30 is composed of a microstrip line, which also includes a quarter-wavelength impedance transformation section, and the main feeder has the same resistance value as the quarter-wavelength impedance transformation section, wherein between adjacent antenna elements The spacing is one wavelength. When a pure resistive load ZL is connected to a transmission line with a characteristic impedance of Z0, if ZL≠Z0, reflected waves will be generated on the transmission line, and the transmission line is in a state of mismatch. At this time, a length of one quarter wavelength is added between the transmission line and the load resistance The matching line can realize the matching between the transmission line and the load, and this circuit segment is the quarter-wavelength conversion segment.

The array antenna 100 also includes a power dividing and combining component connected to the feeding network 30, and the power dividing and combining component is used for distributing the excitation amplitude to the ports according to a preset ratio to realize unequal amplitude feeding. The frequency of wireless energy transmission is mainly two frequency points of 2.45GHz and 5.8GHz. The power splitting and combining component includes a T-shaped power splitter, and the T-shaped power splitter feeds each of the 1×4 antenna line arrays of the patch antenna array 20 in a non-equal-amplitude feeding manner. .

Please refer to Figure 3 for details. The input impedance of each of the antenna elements is 50 ohms. According to the principle of the T-shaped power divider, the resistance is inversely proportional to the square of the amplitude. In order to input the amplitude to each array element port proportionally, four The one-wavelength impedance transformation section is used to realize the impedance change and network matching, and the impedance values of each section of the 1×4 antenna line array in the figure are obtained. The resistance values of the sections of the 1×4 antenna line array are similar, so that the transmission lines in the feeding network are of equal thickness, so as to avoid unnecessary loss and parasitic phenomena affecting the radiation performance. Moreover, if the difference in thickness is too large, when the microwave is transmitted from the too thick microstrip line to the too thin microstrip line, part of the microwave energy will be reflected back to the too thick microstrip line. At this time, the 1×4 feeder network The measured S11 parameter will be relatively high.

Please refer to FIG. 4 for details. A backbone feed network is used to connect four 1×4 antenna arrays, that is, a feed network structure of a 4×4 antenna array. The backbone feeder network is shown in Figure 4, which uses the Taylor distribution method for unequal-amplitude feed. The main feed network has the same resistance value as the quarter impedance transformation section of each section of the 1×4 linear array feed network, and is arranged according to the same rule, so it can have the same effect on the amplitude input distribution, that is, the four The output amplitude ratios from left to right are 0.1484:0.3516:0.3516:0.1484 respectively.

The parasitic loop 40 is arranged around the patch antenna array 20. When the bandwidth of the antenna cannot cover the required frequency band well, the parasitic loop 40 can be added to correspond to the frequency band to improve the performance of some frequency bands and increase the gain. It should be pointed out that the parasitic loop 40 and the patch antenna array 20 are on the same plane, and have the same thickness and material, which is convenient for later processing.

In addition, it should be noted that the ground layer 11, the air support layer 12 and the dielectric substrate 13 are all provided with small holes correspondingly, and the small holes are used for pressing and processing the dielectric plate layer 10, so that the dielectric plate Layers are able to fit tightly together. More specifically, each layer structure has 37 small holes with a diameter of 2 mm, and the small holes can be pressed together by screws.

In order to further illustrate the radiation performance of the antenna array provided by the example of the present invention, please refer to Fig. 5-Fig. The S11 simulation comparison diagram of the array antenna, Fig. 7 is a comparison diagram of the E-plane simulation pattern change of the array antenna provided by the present invention and the microstrip array antenna provided in Fig. 5, Fig. 8 is the array antenna provided by the present invention and that provided in Fig. 5 The comparison diagram of the H-plane simulation pattern change of the microstrip array antenna. In this embodiment, the array antenna provided by the present invention is simulated and compared with the microstrip array antenna, wherein the compared microstrip array antenna includes the ground metal copper layer Copper and the substrate Substrate in sequence, which are the same as the array antenna provided by the present invention. patch antenna array and feed structure.

The S11 parameter is one of the S parameters, which indicates the return loss characteristics. Generally, the dB value and impedance characteristics of the loss are viewed through a network analyzer. This parameter indicates whether the antenna’s emission efficiency is good or not. The larger the value, the reflection of the antenna itself The greater the energy coming back, the less efficient the antenna will be. It can be seen from the S11 simulation comparison diagram in FIG. 6 that the continuous curve represents the S11 change of the 4×4 array antenna provided by the present invention, and the discontinuous curve represents the S11 change of the microstrip array antenna. At the resonant frequency point of 5.8 GHz, the S11 curve of the array antenna of the present invention has a minimum value of about -45.8 dB, and its return loss is relatively small at the working frequency point of 5.8 GHz. It can be clearly seen by observation that the continuous curve has a larger impedance bandwidth than the discontinuous curve, and the continuous curve has two resonance frequency points, and its bandwidth is 4.14% (5.60-5.84GHz). Correspondingly, the bandwidth of the discontinuous S11 curve It is 0.534% (5.782-5.813GHz). In contrast, the bandwidth of the array antenna provided by the present invention is significantly improved compared with the microstrip array antenna.

The angle between two half-power points on both sides of the maximum radiation direction of the main lobe is called the main lobe width, also known as the half-power lobe width. The smaller the width of the main lobe, the more concentrated the electromagnetic energy radiated by the antenna, and the better the directionality. On both sides of the maximum direction of the main lobe, the angle between the two zero radiation directions is called the zero power lobe width. The logarithmic value of the ratio of the power density in the maximum radiation direction of the side lobe to the power density in the maximum radiation direction of the main lobe is called the side lobe level, expressed in dB. Usually the level of the sidelobe closer to the main lobe is higher than that far away, so the level of the sidelobe usually refers to the level of the first sidelobe. It is generally required that the sidelobe level be as low as possible. The logarithmic value of the ratio of the power density in the direction of the maximum radiation of the main lobe to the power density in the direction of the maximum radiation of the rear lobe is called the front-to-back ratio. The larger the front-to-back ratio, the more concentrated the electromagnetic energy radiated by the antenna is in the main radiation direction. Lobe width is a very important parameter commonly used in directional antennas. It refers to the width of the angle formed by the radiation pattern of the antenna below the peak 3dB (the radiation pattern of the antenna is an indicator to measure the ability of the antenna to send and receive signals in all directions, usually Graphically expressed as power intensity versus angle). The vertical lobe width of an antenna is generally related to the coverage radius in the direction corresponding to the antenna.

As can be seen from the simulation pattern change diagrams of Fig. 7 and Fig. 8, the maximum gain of the continuous curve of the 4 × 4 array antenna provided by the present invention is 18.8dB, while the maximum gain of the discontinuous curve of the microstrip array antenna is 13.6dB . It can be seen from the comparison that the gain of the array antenna provided by the present invention is increased by 5.2 dB compared with the traditional array antenna. Moreover, the sidelobe level of the array provided by the present invention is -22.1dB, that is, the sidelobe level is less than -20dB, which meets the requirement of low sidelobe level.

In summary, the present invention provides an array antenna, which sequentially includes a ground layer, a dielectric base layer, a patch antenna array, and a parasitic loop disposed around the patch antenna array. The dielectric plate layer includes an air support layer and a dielectric substrate arranged sequentially from bottom to top, and the patch antenna array is composed of 16 antenna units of 4×4, and the patch antenna array is arranged on the dielectric plate layer Above, the feed network is printed on the dielectric board layer, and the port of the antenna unit is connected to the feed network. The patch antenna array is an antenna plane array composed of four 1×4 antenna line arrays, and the 1×4 antenna line array is arranged in series by four antenna units through the feed network, and the four The 1×4 antenna line array is connected by the main feeder line of the feeder network to form a parallel arrangement. The array antenna provided by the invention has high gain, low sidelobe and wide bandwidth to realize high-efficiency transmission of microwave wireless energy transmission, meet the needs of wireless energy transmission, reduce structural complexity, reduce loss, and has good application prospects.

Those skilled in the art will appreciate from the foregoing description that the broad techniques of the various embodiments of the invention can be implemented in a variety of forms. Therefore, although the various embodiments of the present invention are described in conjunction with specific examples thereof, the real scope of the various embodiments of the present invention should not be so limited, and those of ordinary skill in the art can make further decisions based on the above descriptions. Improvement or transformation, all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (5)

1. An array antenna is characterized by sequentially comprising a ground layer, a dielectric plate layer, a patch antenna array and a parasitic ring arranged on the periphery of the patch antenna array, wherein the dielectric plate layer comprises an air supporting layer and a dielectric substrate which are sequentially arranged from bottom to top, the patch antenna array consists of 16 antenna units of 4 multiplied by 4, the patch antenna array is arranged on the dielectric plate layer, a feed network is printed on the dielectric plate layer, and ports of the antenna units are connected with the feed network;

the air supporting layer is a hollowed substrate serving as a supporting frame, the hollowed processing is designed to be hollowed corresponding to the feed network and the patch antenna array, and a metal thin layer at the bottom of the dielectric substrate is connected with the ground layer to meet the introduction requirement of an air layer;

the feed network comprises a quarter-wavelength impedance transformation section and a T-shaped power divider, and the main feed line and the quarter-wavelength impedance transformation section have the same resistance value;

arranging a hollowed substrate made of Rogers RO4350 material as a support frame;

the parasitic ring is arranged on the periphery of the patch antenna array, and when the bandwidth of the antenna can not completely cover the required frequency band, the required frequency band corresponding to the parasitic ring is increased, the performance of partial frequency band is perfected, and the gain is improved;

the patch antenna array and the parasitic ring are positioned on the same plane, and the thickness and the material of the patch antenna array and the thickness and the material of the parasitic ring are the same, so that the post-processing is convenient;

the grounding layer, the air supporting layer and the dielectric substrate are all correspondingly provided with small holes, and the small holes are used for pressing the dielectric plate layer to enable the dielectric plate layer to be tightly attached together.

2. The array antenna of claim 1, wherein the patch antenna array is an antenna area array composed of four 1x4 antenna linear arrays, the 1x4 antenna linear arrays are arranged in series by four antenna units through the feeding network, and the four 1x4 antenna linear arrays are connected by a trunk feeder of the feeding network to form a parallel arrangement.

3. The array antenna of claim 1, wherein the ground plane is a layer of metallic copper.

4. The array antenna of claim 1, wherein the dielectric substrate is a substrate made of Rogers Ro4350 high frequency material.

5. The array antenna of claim 1, further comprising a power splitting and combining component connected to the feeding network, wherein the power splitting and combining component is configured to distribute excitation amplitudes to the output ports according to a set proportion, so as to implement unequal-amplitude feeding.

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