CN113193384A

CN113193384A - Array antenna

Info

Publication number: CN113193384A
Application number: CN202110360224.3A
Authority: CN
Inventors: 廖斌; 王登; 黄平; 陈小钉
Original assignee: Shenzhen University
Current assignee: Shenzhen University
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2021-07-30
Anticipated expiration: 2041-04-02
Also published as: CN113193384B

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

Array antenna

Technical Field

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

Background

As early as the seventies of the last century, people have put forward the concept of solar space power stations based on microwave energy transmission technology. In the field of solar space power stations, a great deal of research is done abroad. Compared with the traditional energy transmission mode, the microwave energy transmission technology has unique advantages such as no transmission medium, high speed, low loss, easiness in rearrangement and the like. Microwave transmission may also be used in wireless power distribution systems in buildings, and in cars and aircraft that are charged with microwaves. The microstrip antenna, as a new antenna successfully studied in the 70 s of the 20 th century, has been widely used in the fields of microwave wireless energy transmission, aerospace, electronic countermeasure, radar, and the like, with the advantages of simple structure, light weight, low profile, easy conformal installation with the aircraft surface, and integration with microstrip circuit. The antenna gain is used for measuring the ability of the antenna to transmit and receive signals towards a specific direction, and is one of the most important parameters for selecting the microwave wireless energy transmission transmitting antenna, and meanwhile, in order to transmit microwave energy efficiently, the antenna is required to work in a wide frequency band, but the microstrip antenna usually has a bandwidth of only (0.7% -5%), and the application range of the microstrip antenna is limited due to the defects of low gain, narrow frequency band and the like.

In order to improve the transmission efficiency of the microwave wireless energy transmission system, various methods are tried to optimize the transmitting antenna array so as to improve the efficiency, performance and stability of the microwave energy transmission system, and therefore, the demand for a low-cost, high-gain, wide-bandwidth and low-amplitude lobe millimeter wave antenna or array antenna is increasing.

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

Disclosure of Invention

The present invention is directed to provide an array antenna, which aims to increase the gain, reduce the sidelobe, and widen the bandwidth, so as to realize high-efficiency transmission of microwave wireless energy transmission.

The technical scheme adopted by the invention for solving the technical problem is as follows:

an array antenna 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, wherein the medium base layer comprises an air supporting layer and a medium substrate which are sequentially arranged from bottom to top, the patch antenna array consists of 16 antenna units of 4 x4, the patch antenna array is arranged on a medium plate layer, a feed network is printed on the medium plate layer, and ports of the antenna units are connected with the feed network.

In one implementation manner, preferably, the patch antenna array is an antenna area array formed by four 1 × 4 antenna linear arrays, the 1 × 4 antenna linear array is formed by connecting four antenna units in series through the feed network, and the four 1 × 4 antenna linear arrays are connected in parallel by a main feeder of the feed network.

In one implementation manner, preferably, the feed network includes a quarter-wavelength impedance transformation section and a T-type power divider, and the main feed line and the quarter-wavelength impedance transformation section have the same resistance value.

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

In one implementation manner, preferably, the air supporting layer is a substrate subjected to hollowing treatment and used as a supporting frame, and the hollowing treatment is designed to be hollowed corresponding to the feed network and the patch antenna array.

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

In one implementation manner, preferably, the ground layer, the air supporting layer, and the dielectric substrate are respectively provided with a small hole, and the small holes are used for performing press-fitting processing on the dielectric board layer.

In one implementation, preferably, the patch antenna array and the parasitic ring are in the same plane, and have the same thickness and material.

In one implementation manner, preferably, the array antenna further includes a power dividing and combining component connected to the feed network, where the power dividing and combining component is configured to allocate excitation amplitude to the feed port according to a preset proportion, so as to implement unequal-amplitude feeding.

Has the advantages that: the array antenna provided by the invention is provided with a patch antenna array consisting of 16 antenna units of 4 multiplied by 4, and a parasitic ring is arranged on the periphery of the patch antenna array, wherein the array antenna comprises a ground layer, an air supporting layer and a medium substrate which are sequentially arranged from bottom to top, the mixed medium substrate and the parasitic ring jointly realize broadband and high gain, so that the impedance matching of the antenna is effectively improved, the working bandwidth of the array antenna is obviously larger than that of a common single-layer microstrip antenna, the gain of the array antenna can be improved by the patch antenna array and the parasitic ring, and the array antenna with high gain, low side lobe and wide bandwidth is obtained, thereby meeting the requirement of wireless energy transmission, reducing the structural complexity and the loss and having good application prospect.

Drawings

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

fig. 2 is an exploded view of the array antenna provided in the present invention;

fig. 3 is a schematic diagram of a feed network structure of a 1 × 4 antenna linear array provided by the present invention;

fig. 4 is a schematic diagram of a backbone feeder network structure provided by the present invention, which connects four 1 × 4 linear arrays;

fig. 5 is a schematic structural diagram of a conventional microstrip array antenna;

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

FIG. 7 is a graph comparing the E-plane simulated pattern variation of the array antenna provided by the present invention with the microstrip array antenna provided by FIG. 5;

fig. 8 is a graph comparing the H-plane simulated pattern variation of the array antenna provided by the present invention and the microstrip array antenna provided by fig. 5.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the 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 the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have specific orientations, be configured in specific orientations, and operate, and thus, should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. Specific meanings of the above terms in the embodiments of the present invention can be understood in specific cases by those of ordinary skill in the art.

To overcome the above problems of the prior art, the present invention provides an array antenna 100. Referring to fig. 1 to 4, fig. 1 is a schematic structural diagram of an array antenna provided by the present invention, fig. 2 is a schematic structural diagram of an exploded array antenna provided by the present invention, fig. 3 is a schematic structural diagram of a feed network of a 1 × 4 antenna linear array provided by the present invention, and fig. 4 is a schematic structural diagram of a main feed network connecting four 1 × 4 linear arrays provided by the present invention.

The array antenna 100 sequentially includes a dielectric plate layer 10, a patch antenna array (Copper)20, a feed 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 disposed on the dielectric plate layer 10, the feed network 30 is printed on the dielectric plate layer 10, and ports of the antenna units 21 are connected to the feed network 30.

Further, the array antenna 100 comprises a plurality of antenna elements arranged in sequence from bottom to topA ground plane 11, an Air support layer (Air)12 and a dielectric Substrate (Substrate) 13. The ground layer 11 is a metal copper layer, and supports the normal operation of the array antenna. The air supporting layer 12 is a substrate serving as a support frame for hollowing, and the hollowing is designed corresponding to the feed network and the patch antenna array. The present invention provides Rogers RO4350(ε) since the air layer cannot support other structures_r3.66, tan δ is 0.001) as a support frame, and the thickness h is 0.762mm, in order to meet the introduction requirement of an air layer, the air support layer 12 provided by the present invention hollows the feed network 30 and the Rogers RO4350 at the lower portion corresponding to the patch antenna array 20, so as to obtain the air support layer provided by the present invention. The dielectric substrate 13 is made of Rogers Ro4350 high-frequency material, and the thickness h is also 0.762 mm. The thickness of the dielectric substrate 13 is much smaller than the wavelength, and the metal thin layer at the bottom of the dielectric substrate 13 is connected with the grounding layer 11.

Among these, the Rogers RO4350 high frequency material is a glass fiber reinforced (non-PTFE) hydrocarbon/ceramic laminate designed for high volume, high performance commercial applications. RO4350 is intended to provide excellent radio frequency 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, the number of laminates a designer can typically choose is greatly reduced. The RO4350PCB has the characteristics required by RF microwave developers to implement a repeatable design of impedance controlled transmission lines for filters, coupling networks and networks. Low dielectric losses allow the use of RO4350 series materials in many applications, where higher operating frequencies limit the use of laminates for conventional printed circuit boards. The temperature coefficient of dielectric constant, which is one of the lowest temperature coefficients in all printed circuits, is stable over a wide frequency range making it an ideal substrate for broadband applications.

Specifically, the patch antenna array 20 provided by the present invention is an antenna area array composed of four 1 × 4 antenna linear arrays, where the 1 × 4 antenna linear array is formed by connecting four antenna units in series through the feed network, and the four 1 × 4 antenna linear arrays are formed by connecting main feed lines of the feed network 30 in parallel, so as to obtain the patch antenna array 20 composed of 4 × 4 16 antenna units. The 1 × 4 antenna linear arrays are arranged in series, the four 1 × 4 antenna linear arrays are arranged in parallel, and the advantages of series feeding and parallel feeding are integrated through a series-parallel combined feeding mode. Specifically, the patch antenna array 20 is disposed on the dielectric substrate 13, and the feed network 30 is printed on the dielectric substrate 13 and correspondingly connected to the patch antenna array.

The feed network 30 is composed of microstrip lines, and further includes a quarter-wavelength impedance transformation section, the main feed line and the quarter-wavelength impedance transformation section have the same resistance, and the distance between adjacent antenna units is one wavelength. When a pure resistance load ZL is connected with a transmission line with characteristic impedance Z0, if ZL ≠ Z0, a reflected wave is generated on the transmission line, the transmission line is in a mismatch state, and at the moment, a matching line with the length of a quarter wavelength is additionally arranged between the transmission line and the load resistance to realize the matching between the transmission line and the load, and the circuit section is a quarter wavelength conversion section.

The array antenna 100 further includes a power dividing and combining component connected to the feeding network 30, where the power dividing and combining component is configured to distribute excitation amplitudes to the feeding ports according to a preset proportion, so as to implement unequal-amplitude feeding. The wireless energy transmission frequency mainly comprises two frequency points of 2.45GHz and 5.8 GHz. The power dividing and combining component includes a T-type power divider, and the T-type power divider feeds each of the 1 × 4 antenna linear arrays of the patch antenna array 20 in a non-constant amplitude feeding manner.

Referring to fig. 3, the input impedance of each antenna unit is 50 ohms, the resistance is inversely proportional to the square of the amplitude according to the principle of a T-type power divider, and in order to input the amplitude to each array element port in proportion, a quarter-wavelength impedance transformation segment is required to implement impedance change and network matching, so as to obtain the impedance values of each segment of the 1 × 4 antenna linear array in the figure. The resistances of the sections of the 1x4 antenna linear array are similar, so that the thickness of the transmission line in the feed network is equivalent, and unnecessary loss and parasitic phenomena are prevented from influencing the radiation performance. If the difference between the thickness and the fineness is too large, a part of the microwave energy is reflected back to the too thick microstrip line when the too thick microstrip line transmits the microwave to the too thin microstrip line, and the S11 parameter measured by the 1 × 4 feeder line network is higher.

Referring to fig. 4, a main feeding network is used to connect four linear arrays of 1 × 4 antennas, i.e. a feeding network structure of a planar array of 4 × 4 antennas. The main feeder network is shown in fig. 4, and uses a taylor distribution method to perform non-constant amplitude feeding. The resistance values of the quarter impedance transformation sections of the main feed network and the 1x4 linear array feed network are the same, and the main feed network and the quarter impedance transformation sections are arranged according to the same rule, so that the main feed network has the same effect on amplitude input distribution, namely, the amplitude ratios of four ports output from left to right are respectively 0.1484: 0.3516: 0.3516: 0.1484.

the parasitic ring 40 is disposed around the patch antenna array 20, and when the bandwidth of the antenna cannot cover the required frequency band well, the parasitic ring 40 is added to correspond to the frequency band, so as to improve the performance of a part of the frequency band and increase the gain. It should be noted that the parasitic ring 40 and the patch antenna array 20 are in the same plane, and have the same thickness and material, which is convenient for the post-processing.

Besides, it should be noted that the ground layer 11, the air supporting layer 12 and the dielectric substrate 13 are respectively provided with small holes, and the small holes are used for performing a pressing process on the dielectric board layer 10, so that the dielectric board layers can be tightly attached together. More specifically, each layer of the structure had 37 holes with a diameter of 2mm, which were press-fitted by screws.

To further illustrate the radiation performance of the antenna array provided by the embodiment of the present invention, please refer to fig. 5-8, fig. 5 is a schematic structural diagram of a microstrip array antenna, fig. 6 is a simulation comparison diagram of S11 between the array antenna provided by the present invention and the microstrip array antenna provided by fig. 5, fig. 7 is a comparison diagram of E-plane simulation pattern variation between the array antenna provided by the present invention and the microstrip array antenna provided by fig. 5, and fig. 8 is a comparison diagram of H-plane simulation pattern variation between the array antenna provided by the present invention and the microstrip array antenna provided by fig. 5. In this embodiment, the array antenna provided by the present invention is compared with a microstrip array antenna in a simulation mode, where the microstrip array antenna for comparison sequentially includes a grounded Copper metal layer Copper, a Substrate, a patch antenna array and a feed structure, which are the same as those of the array antenna provided by the present invention.

The S11 parameter is one of S parameters, which represents the return loss characteristic, and the dB value and impedance characteristic of the loss are generally seen by a network analyzer, and this parameter represents that the transmission efficiency of the antenna is not good, and the larger the value, the larger the energy reflected by the antenna itself is, so the efficiency of the antenna is worse. As can be seen from the S11 simulation comparison diagram of fig. 6, the continuous curve represents the S11 variation of the 4 × 4 array antenna provided by the present invention, and the discontinuous curve represents the S11 variation of the microstrip array antenna. At the resonant frequency point of 5.8GHz, the S11 curve of the array antenna has the minimum value of about-45.8 dB, and the return loss of the S11 curve at the working frequency point of 5.8GHz is relatively low. The observation shows that the continuous curve has larger impedance bandwidth than the discontinuous curve, the continuous curve has two resonance frequency points, the bandwidth of the continuous curve is 4.14% (5.60-5.84GHz), correspondingly, the bandwidth of the discontinuous S11 curve is 0.534% (5.782-5.813GHz), and compared with the microstrip array antenna, the bandwidth of the array antenna provided by the invention is obviously improved.

The included angle between two half-power points on two sides of the maximum radiation direction of the main lobe is called the width of the main lobe and also called the width of the half-power lobe. The smaller the width of the main lobe, the more concentrated the electromagnetic energy radiated by the antenna and the better the directivity. The angle between two zero radiation directions on both sides of the maximum direction of the main lobe is called the zero power lobe width. The logarithmic value of the ratio of the power density in the direction of maximum radiation of the side lobe to the power density in the direction of maximum radiation of the main lobe, called the side lobe level, is expressed in dB. The side lobe level is usually higher near the main lobe than far away, so the side lobe level is usually referred to as the first side lobe level. It is generally desirable that the side lobe level be as low as possible. The logarithm of the ratio of the power density in the main lobe maximum radiation direction to the power density in the back lobe maximum radiation direction 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 an important parameter commonly used in directional antennas, and refers to the width of an included angle formed at a position 3dB below the peak in the radiation pattern of the antenna (the radiation pattern of the antenna is an index for measuring the ability of the antenna to transmit and receive signals in each direction, and is usually represented graphically as the relationship between power intensity and included angle). The vertical lobe width of an antenna is generally related to the coverage radius in the direction to which the antenna corresponds.

As can be seen from the simulated pattern variation diagrams of fig. 7 and 8, the maximum gain of the continuous curve of the 4 × 4 array antenna provided by the present invention is 18.8dB, and the maximum gain of the discontinuous curve of the microstrip array antenna is 13.6 dB. Through comparison, the gain of the array antenna provided by the invention is improved by 5.2dB compared with the traditional array antenna. The array provided by the invention has the side lobe level of-22.1 dB, namely the side lobe level is less than-20 dB, and the requirement of low side lobe level is met.

In summary, the array antenna provided by the present invention sequentially includes a ground layer, a dielectric substrate, a patch antenna array, and a parasitic ring disposed around 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 x4, 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 1 × 4 antenna linear arrays, the 1 × 4 antenna linear arrays are formed by connecting four antenna units in series through the feed network, and the four 1 × 4 antenna linear arrays are connected by a main feed line of the feed network to form parallel arrangement. 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.

Those skilled in the art will appreciate from the foregoing description that the broad techniques of the embodiments of the present invention can be implemented in a variety of forms. Therefore, while the embodiments of the present invention have been described in connection with particular examples thereof, the true scope of the embodiments of the present invention should not be so limited since modifications and variations thereon will occur to those skilled in the art and are intended to be within the scope of the appended claims.

Claims

1. The array antenna is characterized by sequentially comprising a ground layer, a dielectric base layer, a patch antenna array and a parasitic ring arranged on the periphery of the patch antenna array, wherein the dielectric base 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.

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 main feeder of the feeding network to form a parallel arrangement.

3. The array antenna of claim 2, wherein the feed network comprises a quarter-wavelength impedance transformation section and a T-type power divider, and the main feed line and the quarter-wavelength impedance transformation section have the same resistance.

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

5. The array antenna of claim 1, wherein the air supporting layer is a hollowed substrate as a support, and the hollowed process is hollowed out corresponding to the feeding network and the patch antenna array.

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

7. The array antenna of claim 1, wherein the ground plane, the air supporting layer and the dielectric substrate are provided with holes, and the holes are used for pressing the dielectric board layer.

8. The array antenna of claim 1, wherein the patch antenna array and the parasitic ring are in the same plane and have the same thickness and material.

9. 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.