Disclosure of Invention
In order to solve the technical problems in the background art, the invention provides a wide-angle dual circularly polarized antenna with low transmission loss and low elevation gain enhancement and equipment thereof, and the wide-angle dual circularly polarized antenna has the advantages of simple structure, low cost, low loss, low elevation gain and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a wide-angle dual circularly polarized antenna with low elevation gain enhancement, which comprises a notch wall, a C-shaped feed network, a lower dielectric substrate, an upper dielectric substrate, an inverted U-shaped feed structure, a metal radiation patch and a pair of coaxial adapter connectors, wherein the notch wall is provided with a notch;
the notch wall is arranged around the lower dielectric substrate in a surrounding mode, and the C-type feed network is arranged on the upper surface of the lower dielectric substrate; the C-shaped feed network is provided with a plurality of feed branches and a plurality of comb-shaped artificial surface plasmon structures, and the feed branches are connected with the feed end of the inverted U-shaped feed structure; the inverted U-shaped feed structure is arranged between the C-shaped feed network and the metal radiation patch; the metal radiation patch is arranged on the upper side of the inverted U-shaped feed structure and laid on the upper surface of the upper dielectric substrate; the pair of coaxial adapter connectors are arranged at the tail end of the C-type feed network and located below the lower dielectric substrate.
In one embodiment, the notch wall height determines the gain level of the dual circularly polarized antenna at low elevation angles.
In one embodiment, the notch wall includes a plurality of metal sheets, and the metal sheets are uniformly distributed along the circumferential direction with a set radius and the center of the lower dielectric substrate as the center.
In one embodiment, the dielectric constant of the lower dielectric substrate is the same as the dielectric constant of the upper dielectric substrate.
In one embodiment, the lower surface of the lower dielectric substrate is entirely covered with the conductive medium.
As an implementation manner, a plurality of uniformly distributed comb-shaped artificial surface plasmon structures are etched on the inner side of the structure of the C-type feed network, and a plurality of uniformly distributed feed branches are derived on the outer side of the structure of the C-type feed network.
As an embodiment, the inverted U-shaped feeding structure includes a plurality of identical inverted U-shaped structures, and the inverted U-shaped feeding structures are uniformly distributed along the circumferential direction in a rotating manner with a set radius.
As an implementation mode, each inverted U-shaped structure is provided with a feed end and a short circuit end, and the short circuit end is in short circuit connection with the conductive medium on the lower surface of the lower medium substrate.
In one embodiment, the metal radiating patches comprise a plurality of fan-shaped metal patches spreading outwards from the center, and adjacent fan-shaped metal patches are equally spaced.
In one embodiment, the lower dielectric substrate is disposed on a metal base plate.
A second aspect of the invention provides an apparatus comprising a low elevation gain enhanced wide angle dual circularly polarized antenna as described above.
Compared with the prior art, the invention has the beneficial effects that:
the invention introduces the inverted U-shaped feed structure and the metal radiation patch, so that the section height of the antenna is less than 0.2 lambda0(λ0Wavelength for center frequency pair);
the invention introduces the artificial surface plasmon technology, effectively reduces the transmission loss of the microwave network, improves the radiation gain of the antenna and the signal-to-noise ratio of the communication system, and effectively improves the communication quality of the system.
The invention adopts the technology of combining the double-port feed and the multi-feed point, firstly, N feeds of the antenna are uniformly distributed on the circumference with the radius of D, and the symmetry of the antenna is improved through the multi-feed point technology, thereby realizing the stable design of the phase center of the antenna; secondly, the antenna is fed by adopting a dual-port technology, so that the free switching of the left-handed polarization working mode and the right-handed polarization working mode of the antenna is realized;
the invention introduces the notch wall technology, effectively improves the gain of the antenna at the low elevation angle, realizes the wide beam design of the antenna and improves the radiation pattern of the antenna.
Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Detailed Description
The invention is further described with reference to the following figures and examples.
It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
Currently, circularly polarized antennas are more widely used than linear polarization, and are one of the important issues in antenna theory. There are many methods for implementing circular polarization of an antenna, such as a single-point feeding method and a multi-point orthogonal feeding method for adding perturbation to a single antenna, and a multi-element method consisting of multiple antennas and a feeding network, which are commonly used methods for implementing circular polarization radiation of an antenna.
The design of the single feed method can be analyzed by using a cavity model theory, and the circular polarization is realized by using a merged mode of two radiation orthogonal polarizations. As shown in fig. 1 a to 1 c, the two orthogonal modes are separated from each other in resonance frequency by means of a perturbation or the like applied to the antenna, and circular polarized radiation is formed in the far-field region by utilizing the 90-degree phase difference (leading 45 degrees/lagging 45 degrees) effect of the equivalent impedance phase angles of the two merged modes.
The single feed method is favored by engineers due to its advantages of simple structure, low cost, no need of additional feed network, etc. However, the single-feed circularly polarized antenna has the disadvantages of narrow operating bandwidth, poor polarization characteristics, and low gain at low elevation angles. In order to improve such a situation, a multi-feed method and a multi-element method are generally adopted, however, in the process of realizing circular polarization operation, transmission loss is increased due to introduction of a microwave network, and wide beam and double circular polarization operation characteristics of the antenna cannot be realized. Therefore, the present embodiment adopts a feed technology combining the artificial surface plasmons and the multiple feed points, so that not only is a microwave network with low loss characteristic obtained, but also dual circular polarization operation of the antenna is realized. In addition, by adopting the notch wall loading technology, the gain of the antenna at a low elevation angle is further improved, and the wide-beam working characteristic of the antenna is realized.
Referring to fig. 2, the low elevation gain enhanced wide-angle dual circularly polarized antenna formed in this embodiment forms a concave circular cavity by using a notch wall with a radius Ro and a height Hg, the height of an antenna unit is H, the antenna rotates circumferentially with an origin as a center of a circle and a radius Ri, and the antenna of the embodiment of the present invention is formed.
Specifically, the low-elevation-gain-enhanced wide-angle dual circularly polarized antenna of the present embodiment includes a notch wall 101, a C-shaped feed network 201, a lower dielectric substrate 102, an upper dielectric substrate 300, an inverted U-shaped feed structure 103, a metal radiation patch 302, and a pair of coaxial adapter connectors. The pair of coaxial adapter connectors are a first coaxial adapter 401 and a second coaxial adapter 402, respectively.
The notch wall 101 is arranged on the lower dielectric substrate 102 in a surrounding manner, as shown in fig. 3, the C-type feed network 201 is arranged on the upper surface of the lower dielectric substrate 102; the C-shaped feed network 201 is provided with a plurality of feed branches 204 and artificial surface plasmons 205, and the feed branches 204 are connected with a feed end 304 of the inverted U-shaped feed structure 301; the inverted U-shaped feed structure 301 is disposed between the C-shaped feed network 201 and the metal radiating patch 302; the metal radiating patch 302 is arranged on the upper side of the inverted U-shaped feed structure 301 and laid on the upper surface of the upper dielectric substrate 300; the pair of coaxial adapter connectors are arranged at the tail end of the C-type feed network and located below the lower dielectric substrate. The terminal ends of the C-type feeding network comprise two, namely a first terminal end 202 of the C-type feeding network and a second terminal end 203 of the C-type feeding network. The artificial surface plasmons 205 are arranged on the inner side of the C-type feed network. The artificial surface plasmons arranged at the ports 202 and 203 form transmission transition sections (height h1, h2 and h3 … hn) from low to high from outside to inside, and the comb-shaped artificial surface plasmons structure arranged at the main body part of the C-type feed network consists of a plurality of comb-shaped structures with equal height (Hp), equal width (wp) and uniform distribution. The ground conductor plane 206 is connected to the metal cladding segment on the lower surface of the dielectric layer by a metal shorting post.
In this embodiment, the dielectric constant of the lower dielectric substrate 102 is the same as the dielectric constant of the upper dielectric substrate 300. The lower surface of the lower dielectric substrate 102 is entirely coated with a conductive medium, such as copper.
Specifically, the lower dielectric substrate 102 has a dielectric constant of 2.65, a thickness T1, and a radius Ro of F4B plate, and the lower surface of the lower dielectric substrate is entirely coated with copper, and the upper surface is printed with the C-type power feed network 201. The upper dielectric substrate 300 is an F4B plate with a dielectric constant of 2.65, a thickness of T2 and a radius of Ri, and the upper surface of the upper dielectric substrate is covered with a metal radiation patch 302.
In a specific implementation, as shown in fig. 6, the notch wall 101 is made of metal. The notch wall 101 includes a plurality of metal sheets, and the metal sheets are uniformly distributed around the center of the lower dielectric substrate and along the circumferential direction with a predetermined radius.
For example: the notch wall 101 is formed by N metal sheets with the width Wg and the height Hg, and the metal sheets are uniformly distributed along the circumferential direction by taking the center of the integral structure as the center of a circle and Ro as the radius. The notch walls 101 are arranged at the center of an original point, the number of the notch walls is N, the notch walls rotate along the circumferential direction to form a single-layer thin-wall concave barreled structure, are fixed above the lower medium substrate 102 and are in short circuit connection with the metal copper-clad on the lower surface of the lower medium substrate 102, and therefore a single-layer thin-wall concave disc-shaped structure is formed; the lower dielectric substrate 102 has a circular structure, the lower surface of the lower dielectric substrate is covered with copper, and the upper surface of the lower dielectric substrate is printed with a C-shaped feed network 201.
In a specific implementation, the C-type feeding network 201 is disposed on the upper surface of the lower dielectric substrate 102, and the belly of the structure thereof is connected with N feeding branches 204, forming branch terminals distributed in a star-shaped structure. The feed network end of the C-shaped feed network 201 is connected with the inner core of the coaxial adapter passing through the coaxial adapter mounting hole 104. N comb-shaped concave-convex structures uniformly distributed on the inner side of the C-shaped feed network form an artificial surface plasmon 205 for low-loss transmission; the coaxial adapter is arranged below the lower dielectric substrate 102, and an outer conductor of the coaxial adapter is connected with the lower surface of the lower dielectric substrate 102 through metal copper coating;
specifically, as shown in fig. 5, the inverted U-shaped feeding structure includes several identical inverted U-shaped structures that are uniformly distributed along the circumferential direction in a rotating manner with a set radius. The inverted U-shaped feed structures 301 are arranged above the lower dielectric substrate 102, the number of the inverted U-shaped feed structures is N, the inverted U-shaped feed ends 304 are arranged in the inverted U-shaped feed mounting holes 103 and are connected with the feed network branches 204, and the inverted U-shaped short-circuit ends 303 are connected with the metal copper-clad short circuit on the lower surface of the lower dielectric substrate 102;
as shown in fig. 4, the metal radiating patch 302 is disposed on the upper portion of the inverted U-shaped feeding structure 301, printed on the upper surface of the upper dielectric substrate 300, and made of N fan-shaped structures gradually widening from the center to the edge, and the circular arc portion of the metal radiating patch 302 is connected to the "inverted U" structure; the metal radiation patches comprise N fan-shaped metal patches which are outwards expanded from the center, the distance between every two adjacent fan-shaped radiation patches is equal, and the distance between every two adjacent fan-shaped radiation patches is Ws. In this embodiment, the number of N is greater than 3 and less than 20.
In one embodiment, the notch wall height determines the gain level of the dual circularly polarized antenna at low elevation angles.
Changing the height Hg of the slit wall (101) to 0.05-0.1 lambda0(λ0Center frequency), the gain level of the circularly polarized antenna at a low elevation angle can be effectively improved, and the 3dB beam width of the circularly polarized antenna is widened; and the circularly polarized radiation function of the antenna is obtained by changing the feed sequence of the SMA coaxial adapter at the tail end of the feed network. When the first coaxial crossover 401 is fed, left-handed circularly polarized radiation can be obtained; when the second coaxial crossover joint 402 is fed, right hand circularly polarized radiation can be obtained.
In this embodiment, a pair of coaxial adapter connectors may be implemented using SMA coaxial adapter connectors.
In other embodiments, the lower dielectric substrate is disposed on a metal backplane.
Specific applications of the dual circularly polarized antenna of the present embodiment are given below:
example 1: (certain aircraft for maritime satellite communication)
The first step is as follows: the antenna unit is made of a metal copper material with a silver-plated surface, the notch wall is made of an Fpcb (flash pcb) medium substrate, the power distribution network is made of an F4B medium substrate, and the metal bottom plate is made of a low-density metal aluminum material.
The second step is that: according to the design requirements of the system on the electrical property, the mechanical property, the three prevention (mould prevention, moisture prevention and salt mist prevention) and the space size constraint of the antenna, the design and the co-modeling installation design of the wide-beam circularly polarized antenna are carried out. The height of the antenna is about 0.1 times of the working wavelength, and the optimized 3dB beam width is 157 degrees.
The third step: the inverted U-shaped structure is prepared by adopting a laser cutting and grinding tool stamping mode.
The inverted U-shaped structure is made of a metal copper sheet material with the thickness of 0.4mm, the inverted U-shaped structure is manufactured through laser cutting, and an arc is folded through punching by using a die. 4 sets of antenna units are prepared at one time, and the antenna units are arranged on the dielectric plate in a rotating distribution mode to form a 1 multiplied by 4 circularly polarized area array. And the feed network printed on the lower dielectric substrate is utilized to complete the feed of the circularly polarized antenna through the equal difference phase feed.
The fourth step: and preparing the metal base plate by adopting a CNC (computerized numerical control) machine tool machining mode.
And according to the installation size requirement of the communication equipment and the structural characteristics of the antenna, the metal base plate is subjected to processes such as cutting, machine milling and the like to complete the preparation of the metal base plate.
The fifth step: according to the antenna common mode structure requirement of the communication equipment, a 1 x 4 circular polarization area array is arranged on a metal bottom plate to form a double circular polarization antenna with the characteristics of low section, wide beam, common mode structure and the like.
Example 2: (certain aircraft used as a navigation antenna)
The first step is as follows: the antenna unit is made of a metal copper material with a silver-plated surface, the notch wall is made of an Fpcb (flash pcb) medium substrate, the power distribution network is made of an F4B medium substrate, and the metal bottom plate is made of a low-density metal aluminum material.
The second step is that: according to the design requirements of the system on the electrical property, the mechanical property, the three prevention (mould prevention, moisture prevention and salt mist prevention) and the space size constraint of the antenna, the design and the co-modeling installation design of the wide-beam circularly polarized antenna are carried out. The height of the antenna is about 0.1 times of the working wavelength, and the optimized 3dB beam width is increased by 47 degrees.
The third step: the inverted U-shaped structure is prepared by adopting a laser cutting and grinding tool stamping mode.
The inverted U-shaped structure is made of a metal copper sheet material with the thickness of 0.4mm, the inverted U-shaped structure is manufactured through laser cutting, and an arc is folded through punching by using a die. 4 sets of antenna units are prepared at one time, and the antenna units are arranged on the dielectric plate in a rotating distribution mode to form a 1 multiplied by 4 circularly polarized area array. And the feed network printed on the lower dielectric substrate is utilized to complete the feed of the circularly polarized antenna through the equal difference phase feed.
The fourth step: and preparing the metal base plate by adopting a CNC (computerized numerical control) machine tool machining mode.
And according to the installation size requirement of the communication equipment and the structural characteristics of the antenna, the metal base plate is subjected to processes such as cutting, machine milling and the like to complete the preparation of the metal base plate.
The fifth step: according to the antenna common mode structure requirement of the communication equipment, a 1 x 4 circular polarization area array is arranged on a metal bottom plate to form a double circular polarization antenna with the characteristics of low section, wide beam, common mode structure and the like.
The following is further explained with the simulation result:
the left-handed circularly polarized far-field pattern of the area array antenna used in the above embodiment was simulated by using commercial simulation software HFSS — 19.0, and the result is shown in fig. 7. Wherein, FIG. 7 shows the left-handed circularly polarized antenna used in the example at the center frequency f0Normalized far-field radiation pattern of (a).
The left-handed circularly polarized far-field pattern of the area array antenna used in the above embodiment was simulated by using commercial simulation software HFSS — 19.0, and the result is shown in fig. 8. Therein, fig. 8 is a normalized far-field radiation pattern of the right-hand circularly polarized antenna employed in the example at a center frequency f 0.
Referring to fig. 7, the antenna selected for the embodiment is at the center frequency f0And a far-field radiation directional pattern in a left-hand circular polarization state, wherein the directional pattern is a peach-shaped directional radiation directional pattern, and the 3dB beam width is 158 degrees.
Referring to fig. 7, the far-field radiation pattern of the selected antenna in the embodiment at the center frequency f0 and the right-hand circular polarization state is shown as a "peach-shaped" directional radiation pattern with a 3dB beamwidth of 157 degrees.
In other embodiments, there is also provided an apparatus comprising a low elevation gain enhanced wide angle dual circularly polarized antenna as described above.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.