Composite space-fed array antenna based on three-dimensional circuit

Abstract

The invention discloses a composite air-fed array antenna based on a three-dimensional circuit. The composite air-fed array antenna comprises a grounding plate; the antenna layer is arranged on one side of the grounding plate, and the antenna layer comprises an antenna unit; and the radiation port surface layer is arranged on one side, far away from the grounding plate, of the antenna layer, the radiation port surface layer comprises radiation units corresponding to the antenna units, and each radiation unit comprises at least two radiation ports. The antenna unit couples energy to the radiation unit, so that the antenna can radiate electromagnetic waves to a free space, and the relative bandwidth of the antenna is larger.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave transmission, and in particular to a compound air-fed array antenna based on a three-dimensional circuit. BACKGROUND

[0002] The loss of the feed network has a great influence on the performance of the planar array, and the combination mode of the feed network and the antenna unit also relates to the overall complexity of the array. Therefore, it is very important to select a suitable transmission line and a corresponding array arrangement mode. Common transmission lines include waveguides, microstrip lines and substrate integrated waveguides. Air waveguides have high power capacity and very low transmission loss, but their own profile is relatively high and they are not easy to integrate with the system. Microstrip lines are planar structure transmission lines, have a low profile, are easy to process and integrate, but their loss is high at high frequency bands. Substrate integrated waveguides combine the advantages of microstrip lines and air waveguides, have a low profile, low loss and are easy to process. Although the loss of the substrate integrated waveguide is lower than that of the microstrip line, its loss still cannot meet the actual engineering requirements at high frequencies, especially in the millimeter wave band. SUMMARY

[0003] The present application aims to provide a compound air-fed array (CAFA) antenna based on a three-dimensional circuit (TCB) to solve the technical problems of high loss, low efficiency and non-autonomous control of key links of ultra-thin high-frequency high-speed circuits and radio frequency antenna front ends at millimeter wave and above frequency bands.

[0004] To achieve the above-mentioned purpose, the present application provides a compound air-fed array antenna based on a three-dimensional circuit, comprising: a ground plate; an antenna layer arranged on one side of the ground plate, the antenna layer comprising antenna units; and a radiation aperture surface layer arranged on the side of the antenna layer away from the ground plate, the radiation aperture surface layer comprising radiation units corresponding to the antenna units, each radiation unit comprising at least two radiation apertures.

[0005] In an embodiment, the geometric center of the antenna unit is in the orthographic projection of the ground plate, and the geometric center of the radiation unit is in the orthographic projection of the ground plate.

[0006] In an embodiment, the radiation aperture surface layer comprises: first side plates, two first side plates are arranged opposite to each other, and each first side plate extends along a first direction; and a connecting plate connected between the two first side plates in a second direction and located on the side away from the ground plate; wherein the connecting plate comprises at least two spaced-apart radiation apertures.

[0007] In an embodiment, in each antenna unit, comprising: a dielectric plate comprising a body part and an air cavity, the air cavity protruding from the body part in the third direction, the air cavity comprising a top surface and a sidewall located at the edge of the top surface; a metal patch disposed on the top surface of the air cavity; and a metal strip disposed on the sidewall of the air cavity; wherein the metal patch in each antenna unit at least partially overlaps the radiation port in each radiation unit in the orthographic projection of the ground plate.

[0008] In an embodiment, the geometric center of the metal patch in each antenna unit in the orthographic projection of the ground plate coincides with the geometric center of the connecting plate in each radiation unit in the orthographic projection of the ground plate.

[0009] In an embodiment, the distance between the connecting plate 302 and the end of the first side plate 301 away from the ground plate 1 is 1-3 mm.

[0010] In an embodiment, in each radiation unit, the radiation port surface layer further comprises: a second side plate, two second side plates are oppositely arranged, and each second side plate is connected between the two first side plates in the second direction and located at the end of the first side plate; wherein the second side plate cooperates with the ends of the two first side plates to form an open.

[0011] In an embodiment, in each radiation unit, the connecting plate comprises: a first connecting rib connected between the two second side plates in the first direction and located between the two first side plates; and / or a second connecting rib connected between the two first side plates in the second direction and located between the two second side plates.

[0012] In an embodiment, the radiation port surface layer has a first size a in the second direction, 0.25λ≤a≤0.45λ; the radiation port has a second size b in the first direction, 0.4λ≤b≤0.6λ.

[0013] In an embodiment, the antenna unit has a third size c in the first direction, 1λ≤c≤2λ; the antenna unit has a fourth size d in the third direction, 0.45λ≤d≤0.55λ; wherein λ is the wavelength corresponding to the center frequency of the working frequency band of the antenna.

[0014] The technical effect of the present application is to provide a composite air-fed array antenna based on a three-dimensional circuit, which comprises a ground plate, an antenna layer and a radiation port surface layer. The antenna layer is arranged on one side of the ground plate, and the antenna layer comprises at least one antenna unit. The radiation port surface layer is arranged on the side of the antenna layer away from the ground plate, and the radiation port surface layer comprises radiation units corresponding to the antenna units, and each radiation unit comprises at least two radiation ports. In this way, the antenna unit couples energy to the radiation unit, so that the antenna can radiate electromagnetic waves to the free space, and the relative bandwidth of the antenna is larger. BRIEF DESCRIPTION OF DRAWINGS

[0015] The technical solutions and other beneficial effects of the present application will be apparent from the detailed description of the specific embodiments of the present application, with reference to the accompanying drawings.

[0016] Figure 1 A structural schematic diagram of a one-dimensional linear array of a composite space-fed array antenna based on a three-dimensional circuit is provided for an embodiment of the present application.

[0017] Figure 2 A cross-sectional view of an antenna layer is provided for an embodiment of the present application.

[0018] Figure 3 A structural schematic diagram of an antenna layer from one perspective is provided for an embodiment of the present application.

[0019] Figure 4 A structural schematic diagram of a radiation aperture layer of a one-dimensional linear array is provided for an embodiment of the present application.

[0020] Figure 5 A structural schematic diagram of a radiation unit is provided for an embodiment of the present application.

[0021] Figure 6a A diagram showing the frequency response of the change of the height a of a radiation aperture layer on return loss is provided for an embodiment of the present application.

[0022] Figure 6b A diagram showing the frequency response of the change of the length b of a radiation aperture on return loss is provided for an embodiment of the present application.

[0023] Figure 7a A diagram showing the frequency response of the change of the physical aperture of an antenna unit on return loss is provided for an embodiment of the present application.

[0024] Figure 7b A diagram showing the frequency response of the change of the physical aperture of an antenna unit on gain is provided for an embodiment of the present application.

[0025] Figure 7c A diagram showing the radiation efficiency and total efficiency of a one-dimensional linear array is provided for an embodiment of the present application.

[0026] Figure 7d Main polarization and cross-polarization patterns of the E-plane and H-plane in a one-dimensional linear array are provided for an embodiment of the present application.

[0027] Figure 8a A structural schematic diagram of a feed network is provided for an embodiment of the present application.

[0028] Figure 8b A diagram showing the transmission performance of a one-in-four equal power division feed network of a one-dimensional linear array is provided for an embodiment of the present application.

[0029] Figure 9The switching structure diagram of the coaxial test connector provided by the embodiment of the application mainly embodies the structure of the switching one-to-two layered circuit board transmission line of the coaxial test connector.

[0030] Figure 10 The 32-unit rectangular array feeding structure diagram provided by the embodiment of the application mainly embodies the rectangular array general feeding line of the Ka receiving end based on the switching test structure.

[0031] Figure 11a The frequency response diagram of the 32-unit rectangular array return loss provided by the embodiment of the application.

[0032] Figure 11b The frequency response diagram of the 32-unit rectangular array gain provided by the embodiment of the application.

[0033] Figure 11c The main polarization and cross polarization patterns of the intermediate frequency E plane and H plane of the 32-unit rectangular array provided by the embodiment of the application.

[0034] The components in the drawings are identified as follows:

[0035] 1 ground plate; 2 antenna layer; 21 antenna unit; 201 dielectric plate; 211 body part; 212 air cavity; 213 convex strip; 121 top surface; 122 side wall; 202 metal patch; 203 metal conducting strip; 3 radiation port surface layer; 31 radiation unit; 32 radiation port; 301 first side plate; 302 connecting plate; 321 first connecting rib; 322 second connecting rib; 303 second side plate; 30 opening; X first direction; Y second direction; Z third direction; 4 TCB transmission line; 41 input port; 42 output port. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person skilled in the art without creative work fall within the protection scope of the application.

[0037] The direction terms mentioned in the application, such as “up”, “down”, “front”, “back”, “left”, “right”, “inner”, “outer”, “side surface” and the like, are only the directions in the drawings, and the direction terms used in the text are used to explain and describe the application, rather than to limit the protection scope of the application.

[0038] In the drawings, like reference numerals refer to like parts throughout the various views. Also, for purposes of explanation, dimensions and values in the drawings are arbitrary and not necessarily to scale.

[0039] With the rapid growth of 5G service demand, the number of wireless communication users is increasing. In mobile communication systems, there are multipath effects, polarization mismatches, and various interferences in space, and the original communication system capacity cannot meet the needs of users, so high-gain and high-efficiency antennas have become a research hotspot. There are mainly two design ideas for high-gain antennas. The first is to use a large-aperture reflector antenna or a lens antenna. This kind of antenna uses air as the medium for feeding, so it has the characteristics of high efficiency, simple feeding, and easy processing. However, in order to achieve high-gain performance, the reflector antenna generally has a high profile and insufficient design flexibility, which makes it difficult to apply to high-frequency communication systems. The second design idea is to arrange antenna elements on a plane according to certain rules, that is, to improve the gain by arranging the array. As long as the low-profile characteristics of the antenna elements are guaranteed, the profile height of the array must be much smaller than that of the reflector antenna. Using a feed network can flexibly control the amplitude and phase of the antenna elements, thereby controlling the radiation direction of the high-gain beam, while it is more difficult to use a reflector antenna for beam scanning. Planar array antennas also have shortcomings, such as increased design complexity and processing cost due to the feed network. In addition, the aperture efficiency of the array will be significantly reduced due to the loss of the feed network and the coupling between the antenna elements. The air-fed array combines the advantages of low-loss reflector antennas and planar array antennas, and has become a popular direction of current antenna research.

[0040] The above-mentioned loss of the feed network has a great influence on the performance of the planar array, and the combination method of the feed network and the antenna elements also relates to the overall complexity of the array. Therefore, it is very important to choose the appropriate transmission line and the corresponding arrangement method. Commonly used transmission lines include waveguides, microstrip lines, and substrate integrated waveguides. Air waveguides have high power capacity and very low transmission loss, but their own profile is relatively high and not easy to integrate with the system. Microstrip lines are planar structure transmission lines with low profile, easy to process and integrate, but their loss is high at high frequencies. Substrate integrated waveguides combine the advantages of microstrip lines and air waveguides, with low profile, low loss, and easy processing. Although the loss of the substrate integrated waveguide is lower than that of the microstrip line, its high-frequency loss still cannot meet the actual engineering requirements.

[0041] The three-dimensional circuit of the present application can also be referred to as a new type of three-dimensional hollow stereoscopic circuit, which comprises a ground plate, an antenna layer and a radiation port surface layer. The antenna layer is arranged on one side of the ground plate, and the antenna layer comprises at least one antenna unit. The radiation port surface layer is arranged on the side of the antenna layer away from the ground plate, and the radiation port surface layer comprises a radiation unit corresponding to the antenna unit, and each radiation unit comprises at least two radiation ports. In this way, the antenna unit couples energy to the radiation unit, so that the antenna can radiate electromagnetic waves to the free space.

[0042] The present application aims at the problems of high loss, low efficiency, non-autonomous controllability of key links of ultra-thin high-frequency high-speed circuits and radio frequency antenna front ends in millimeter wave and above frequency bands, and integrates the new three-dimensional hollow stereoscopic circuit theory architecture, process technology and design method into antenna design. Based on the theory of micro-nano technology, laser process and high-frequency low-loss material, a composite feed array antenna based on three-dimensional stereoscopic circuit is provided by combining the antenna array and the multi-layer circuit. The following will be described in detail.

[0043] Figure 1 The structure schematic diagram of the one-dimensional linear array of the composite feed array antenna based on three-dimensional stereoscopic circuit provided by an embodiment of the present application is shown.

[0044] As shown in Figure 1 , the one-dimensional linear array of the composite feed array antenna based on three-dimensional stereoscopic circuit comprises a ground plate 1, an antenna layer 2 and a radiation port surface layer 3.

[0045] Figure 2 The structure schematic diagram of the antenna layer 2 provided by an embodiment of the present application is shown. Figure 3 The structure schematic diagram of the antenna layer from one perspective, i.e. the bottom view, provided by an embodiment of the present application is shown.

[0046] As shown in Figures 1 to 3 , the antenna layer 2 is arranged on one side of the ground plate 1, Figure 2 It is shown that the antenna layer 2 is arranged on the ground plate 1, and the antenna layer 2 comprises at least one antenna unit 21, which can be one, two, three or more, without being limited herein.

[0047] In an embodiment, in each antenna unit 21, the antenna layer 2 comprises a dielectric plate 201, a metal patch 202 and a metal strip 203.

[0048] Specifically, the dielectric plate 201 comprises a body part 211 and an air cavity 212, and the air cavity 212 protrudes from the body part 211 in the third direction Z. It can be understood that a part of the bottom of the dielectric plate 201 is hollowed out to form the air cavity 212. The air cavity 212 comprises a top surface 121 and a side wall 122 located at the edge of the top surface 121.

[0049] The medium plate 201 further comprises protrusions 213, two protrusions 213 are oppositely arranged, and each protrusion 213 is arranged at a side of the body part 211 in the second direction Y.

[0050] The metal patch 202 (may be referred to as a radiation patch, a patch antenna, or an antenna) is arranged on the top surface 121 of the air cavity 212. It can be understood that a metal patch 202 for radiation is covered on the upper surface of the medium plate 201. The shape of the metal patch 202 includes but is not limited to a rectangle, a circle, an ellipse, a “king” shape, or other special-shaped structures (such as a butterfly shape or a water drop shape).

[0051] The metal strip 203 (may be referred to as a TCB feed line) is arranged on the side wall 122 of the air cavity 212 and close to one side of the ground plate 1. Figure 2 It is shown that the metal strip 203 is arranged on the inner side wall 122 of the air cavity 212. Specifically, the metal strip 203 directly transitions from the bottom layer of the medium plate 201 to the metal patch 202 on the top surface 121 of the air cavity 212 at a certain angle. The metal strip 203 couples energy to the radiation unit 31 above the air cavity 212 through the metal patch 202, so that the antenna can radiate electromagnetic waves to the free space. Since part of the air replaces the medium, the loss generated in the process of energy transmission to the antenna is low, thereby improving the radiation efficiency of the antenna. The advantage of the coupling feed is that the relative position of the feed structure and the radiation unit 31 can be easily controlled, and the degree of freedom of the antenna design is increased.

[0052] The metal strip 203 can extend along the inner side wall 122 of the air cavity 212, and the orthographic projection of the metal patch 202 on the ground plate 1 can be arranged apart from the orthographic projection of the metal strip 203 on the ground plate 1, so as to form a coupling feed mode of the metal strip 203 to the metal patch 202, which is conducive to the expansion of the bandwidth. Alternatively, in other embodiments, the orthographic projection of the metal patch 202 on the ground plate 1 can partially overlap the orthographic projection of the metal strip 203 on the ground plate 1, so that the coupling feed mode of the metal strip 203 to the metal patch 202 can also be formed, which is conducive to the expansion of the bandwidth.

[0053] In an embodiment, the air cavity 212 is a back cavity structure, which can bring the following advantages to the design of the antenna feeder system:

[0054] The antenna layer 2 further comprises a TCB transmission line 4 connected to the metal strip 203, which can make the feed between the TCB transmission line 4 and the metal patch 202 away from the ground plane, and there is enough space to adjust the structure of the feed, thereby bringing more degrees of freedom to the design of the antenna coupling feed;

[0055] A large amount of dielectric is removed between the metal patch 202 and the ground plane 1, allowing most of the fields to be transmitted in air, resulting in a significant reduction in dielectric loss compared to traditional patch antennas.

[0056] At this time, the TCB transmission line 4 and the metal patch 202 are distributed on the front and back sides of the same dielectric board 201. In actual processing, only one component is required to complete the layout of the feeder and the antenna, thus achieving a high degree of integration and integration of the antenna and feeder.

[0057] In one embodiment, the radiation port layer 3 is disposed on the side of the antenna layer 2 away from the ground plane 1. Figure 1 It is shown that the radiation port layer 3 is disposed on the top of the antenna layer 2. The radiation port layer 3 and the antenna layer 2 can be connected by means such as adhesion, snap connection, and threading.

[0058] The radiation port layer 3 includes radiation units 31 corresponding to the antenna units 21, and each radiation unit 31 includes at least two radiation ports 32 (which can be called slots). Thus, the antenna unit 21 couples energy to the radiation unit 31, enabling the antenna to radiate electromagnetic waves into free space. Moreover, the relative bandwidth of the antenna is larger.

[0059] The reason is that the air cavity antenna only uses the metal patch 202 on the dielectric board 201 as its main radiation source. After loading the radiation port layer 3 above the air cavity 212, part of the electromagnetic waves radiated by the metal patch 202 are reflected after passing through the radiation port layer 3. The electromagnetic waves oscillate back and forth in this semi-closed cavity, generating multiple resonances, exciting multiple modes, thereby expanding the bandwidth, and finally radiating out through the radiation ports 32.

[0060] The material used for the radiation port layer 3 is a metal material, such as iron, copper, molybdenum, nickel, etc. Figure 1 It can be seen that the end structure (i.e., the side view) of the radiation port layer 3 is approximately in the shape of "冂" or "H", which can form a weak resonance cavity. On the one hand, it can increase the antenna bandwidth, and on the other hand, it can improve the cross-polarization ratio.

[0061] Figure 4 This is a schematic structural diagram of a one-dimensional linear array of the composite air-fed array antenna provided by the embodiment of the present application.

[0062] In one embodiment, as Figures 1 to 4 shown, the radiation port layer 3 can include more than 4 radiation units 31, each radiation unit 31 can include more than 4 radiation ports 32, and the apertures of each radiation port 32 are the same. The orthographic projection of the metal patch 202 in each antenna unit 21 on the ground plane 1 at least partially coincides with the orthographic projection of the radiation ports 32 in each radiation unit 31 on the ground plane 1. Thus, the metal patch 202 can further radiate electromagnetic waves to the radiation port layer 3.

[0063] Figure 5 A structure diagram of a radiation port surface layer 3 of a radiation unit 31 provided in an embodiment of the present application.

[0064] In an embodiment, as shown in Figure 1 、 Figure 4 、 Figure 5 The radiation port surface layer 3 includes a first side plate 301, a first side plate 301, and a connecting plate 302. The two first side plates 301 are oppositely arranged, and each first side plate 301 extends along the first direction X. Each first side plate 301 is correspondingly arranged on the protrusion 213, and the thickness of the first side plate 301 in the second direction Y is equal to the thickness of the protrusion 213 in the second direction Y. The dielectric plate 201 cooperates with the first side plate 301 and the connecting plate 302 to form a radiation chamber.

[0065] The connecting plate 302 is connected between the two first side plates 301 in the second direction Y and is located away from the ground plate 1. The connecting plate 302 includes at least two spaced-apart radiation ports 32. That is, the metal patch 202 of one antenna unit 21 can be correspondingly arranged with two radiation ports 32.

[0066] The connecting plate 302 is a hollow structure, and the general shape of the connecting plate 302 includes but is not limited to a rectangle, a circle, an ellipse, a "king" shape, etc., or other special-shaped structures (such as a butterfly shape, a water drop shape). The shape of the radiation port 32 includes but is not limited to a rectangle, a circle, an ellipse, a polygon, etc., which will not be described one by one here.

[0067] In an embodiment, the geometric center of the antenna unit 21 in the orthographic projection of the ground plate 1 coincides with the geometric center of the radiation unit 31 in the orthographic projection of the ground plate 1. In this way, the metal patch 202 can radiate electromagnetic waves to the radiation port surface layer 3. The shapes of the antenna unit 21 and the radiation unit 31 can be any one of a rectangle, a square, a circle, or other figures with certain symmetry, which will not be particularly limited here as long as the geometric centers of the two in the orthographic projection of the ground plate 1 coincide. Among them, the geometric center is the center position of a geometric figure, such as the center of a circle, the center of a sphere, the intersection of two opposite sides of a parallelogram, etc.

[0068] Further, the geometric center of the metal patch 202 in each antenna unit 21 in the orthographic projection of the ground plate 1 coincides with the geometric center of the connecting plate 302 in each radiation unit 31 in the orthographic projection of the ground plate 1.

[0069] In each radiation unit 31, the radiation surface layer 3 further comprises a second side plate 303, two second side plates 303 are oppositely arranged, and each second side plate 303 is connected to the two first side plates 301 in the second direction Y and located at the end of the first side plate 301. The second side plate 303 is arranged between the two radiation units 31, which can improve the overall strength and structural stability of the entire radiation surface layer 3. Among them, the second side plate 303 cooperates with the end of the two first side plates 301 to form an opening 30. In this way, the radiation surface layer 3 forms a semi-closed structure.

[0070] In an embodiment, the height of the second side plate 303 in the second direction Y is less than the height of the first side plate 301 in the second direction Y, so that the aperture of the opening 30 is larger. Of course, the height of the first side plate 301 and the second side plate 303 can also be set according to actual needs, which will not be described here.

[0071] In an embodiment, as shown in Figure 4 In each radiation unit 31, the connecting plate 302 comprises a first connecting rib 321, which is connected between the two second side plates 303 in the first direction X and located between the two first side plates 301. Among them, the first connecting rib 321 cooperates with part of the first side plate 301 and part of the second side plate 303 to form a radiation port 32. Of course, two radiation ports 32 can also be separated by the first connecting rib 321.

[0072] In an embodiment, as shown in Figure 4 In each radiation unit 31, the connecting plate 302 comprises a second connecting rib 322, which is connected between the two first side plates 301 in the second direction Y and located between the two second side plates 303. Among them, the second connecting rib 322 cooperates with part of the first side plate 301 and part of the second side plate 303 to form a radiation port 32. Of course, two radiation ports 32 can also be separated by the second connecting rib 322.

[0073] In an embodiment, the distance (vertical distance) between the connecting plate 302 and the end of the first side plate 301 away from the ground plate 1 is 1-3mm, so as to ensure the structural strength of the radiation surface layer 3. Among them, the radiation surface layer 3 is formed by injection molding process. It can be understood that the distance (unit: mm) between the connecting plate 302 and the first side plate 301 can be one value or a value within the range of any two values selected from 1, 1.5, 2, 2.5 and 3.

[0074] In an embodiment, in each radiation unit 31, the connecting plate 302 comprises a first connecting rib 321 and a second connecting rib 322, and the first connecting rib 321 and the second connecting rib 322 are cross arranged, so that the connecting plate 302 is provided with a plurality of radiation ports 32, for example Figure 5 Each radiation unit 31 in the above embodiment has four radiation ports 32.

[0075] In an embodiment, the plurality of first connecting ribs 321 are arranged at intervals in the second direction Y, and each first connecting rib 321 extends along the first direction X. The plurality of second connecting ribs 322 are arranged at intervals in the first direction X, and each second connecting rib 322 extends along the second direction Y. In this way, the connecting plate 302 in each radiating unit 31 is provided with a plurality of radiation ports 32, for example, the number (unit: pieces) of radiation ports 32 can be 6, 8, 10, 12, etc., refer to Figure 4 , which will not be described one by one here.

[0076] In an embodiment, the radiation port surface layer 3 has a first size a in the second direction Y, 0.25λ≤a≤0.45λ; the radiation port 32 has a second size b in the first direction X, 0.4λ≤b≤0.6. Wherein, λ is the wavelength corresponding to the center frequency of the working frequency band of the antenna. It can be understood that the first size a can be one value or a value within the range between any two values of 0.25, 0.3, 0.35, 0.4, 0.45. The second size b can be one value or a value within the range between any two values of 0.4, 0.45, 0.5, 0.55, 0.6.

[0077] The antenna unit 21 has a third size c in the first direction X, 1λ≤c≤2λ; the antenna unit 21 has a fourth size d in the third direction Z, 0.45λ≤d≤0.55λ. It can be understood that the third size c can be one value or a value within the range between any two values of 1, 1.2, 1.5, 1.8, 2. The fourth size d can be one value or a value within the range between any two values of 0.45, 0.48, 0.5, 0.52, 0.55.

[0078] Embodiments of the present application cover a semi-closed radiation port surface layer 3 above the air cavity antenna, and the radiation port surface layer 3 is provided with four radiation ports 32 (radiation slots) of the same size. Therefore, such a CAFA antenna can be regarded as a hybrid structure of P-CAFA and M-CAFA. From the optimized return loss results, the size of the radiation port 32 on the radiation port surface layer 3 and the height of the radiation port surface layer 3 have a great influence on the resonant frequency of the antenna.

[0079] In combination with Figure 6a , it is shown that Figure 6a the change of the height a of the radiation port surface layer has a frequency response on the return loss. Figure 6a It is shown that the curves of the height a of the radiation port surface layer being 5.1mm, 5.2mm, and 5.3mm, as the height a of the radiation port surface layer decreases, the low-frequency resonant point moves to the high-frequency direction, the return loss of the antenna becomes better, and the relative bandwidth becomes smaller.

[0080] In combination with Figure 6bAs shown, Figure 6b The change of the length b of the radiation port 32 is shown to affect the frequency response of the return loss. Figure 6b The curves of the length b of the radiation port 32 being 7.7 mm, 7.8 mm and 7.9 mm are shown. As the length b of the radiation port decreases, the high-frequency resonance point moves to the high-frequency direction, the resonance depth of the return loss of the antenna decreases, and the relative bandwidth increases.

[0081] Figure 7a The change of the physical aperture of the antenna unit provided by the embodiment of the present application affects the frequency response of the return loss. Figure 7b The change of the physical aperture of the antenna unit provided by the embodiment of the present application affects the frequency response of the gain.

[0082] The key parameters are optimized, and the results are shown in Figures 7a-7b The return loss = -20log|s11|, and the return loss of the antenna port is greater than 20 dB within 18.7-20.2 GHz. The gain of the antenna center frequency is close to 10 dB, which is 3 dB higher than the gain of the conventional air-backed cavity antenna. This is because the radiation port surface layer compresses the H-plane beam, resulting in a decrease in beam width and ultimately improving the gain. The physical aperture (area) of the antenna unit is 25 mm*7.5 mm, and the intermediate frequency aperture efficiency is about 0.998.

[0083] Figure 7c The radiation efficiency (Rad. efficiency) and the total efficiency (Tot. efficiency) of the one-dimensional linear array composed of the above-mentioned antenna unit are shown, which mainly reflects the degree of gain reduction compared with the ideal case. The actual intermediate frequency gain is reduced by 0.24 dB (corresponding to the total efficiency) compared with the ideal intermediate frequency gain, and at this time the total aperture efficiency of the array is more than 95%, which is much higher than the aperture efficiency of other types of antennas in this frequency band.

[0084] Figure 7d The main polarization and cross-polarization patterns of the intermediate frequency E-plane and H-plane of the one-dimensional linear array are shown. As shown in Figure 7d The cross-polarization ratio of the E-plane and H-plane of the antenna unit is greater than 30 dB, which meets the engineering index. The cross-polarization ratio is the difference between the main polarization and the cross-polarization of the same plane. After loading the radiation port surface layer with the radiation port, the electric field direction of the main polarization wave is perpendicular to the radiation port, and the polarization wave can directly pass through the radiation port; while the electric field direction of the cross-polarization wave is parallel to the radiation port, and the polarization wave is reflected to the inside of the air cavity. After multiple reflections, the antenna unit can finally radiate a linearly polarized wave with very high purity.

[0085] There are generally two layout methods for array antenna feeding networks: series feeding and parallel feeding. The advantage of series structure is that it saves vertical layout space, but the disadvantage is that it is affected by dispersion effects. The wider the required bandwidth and the larger the antenna element size, the greater the maximum phase difference between the ports. For this linear array, it is desirable for each antenna element to have equal amplitude and in-phase input. Therefore, when the layout space allows, two equally divided parallel elements are combined to form a one-to-four power-dividing feeding network.

[0086] Figure 8a A schematic diagram of the power supply network is shown. (For example...) Figure 8a As shown in the diagram, this structure demonstrates that the signal path along the input port 41 of the TCB transmission line 4 to each output port 42 is completely consistent, effectively resolving the phase issue. After optimization, the simulation results are as follows: Figure 8b As shown. Within the 18.7-20.2 GHz range, the return loss at input port 41 is greater than 30 dB, the transmission coefficient from the input port to each output port 42 is within the range of -6.2 ± 0.02 dB, the transmission loss is less than 0.22 dB, and the phase difference is almost 0 degrees. It should be noted that... Figure 8b In the diagram, S1,1 is the reflection coefficient of port 41, and S2,1, S3,1, S4,1, and S5,1 are the transmission coefficients from port 41 to each of the four output ports 42. The curves S2,1, S3,1, S4,1, and S5,1 largely overlap due to good consistency, so only one curve is visible; the other is curve S1,1.

[0087] Due to the special structure of the TCB transmission line, a suitable conversion structure was designed in the 18.7GHz-20.2GHz frequency band to meet the testing requirements of the composite air-feed array subsystem.

[0088] Figure 9 The diagram illustrates the connection structure of a coaxial test connector, primarily demonstrating its connection to a 1-to-2 TCB transmission line. Figure 9 As shown, the current adapter test interface still uses a coaxial test connector design: the metal conductor of the TCB is raised to the lower surface of the FR-4 (FR4 copper clad laminate) via a dielectric ramp, forming a metal disk that contacts it, enabling the transmission of electrical performance. Furthermore, to further reduce the length of the metal conductor, this adapter structure is directly connected to a 1-to-2 power divider, resulting in a special adapter structure from a coaxial test connector to a 1-to-2 TCB transmission line. The port on the 1-to-2 TCB transmission line side can then be directly connected to the feed network, forming a complete, testable composite air-feed array antenna.

[0089] Figure 10The 32-unit rectangular array feed structure schematic diagram provided in the embodiment of the present application mainly embodies the rectangular array overall feed of the Ka receiving end based on the switching test structure. As shown in Figure 10 , the period of the narrow edge direction (Y direction in Figure 10 ) of the four-unit linear array is set to 8, and finally the 32-unit rectangular array is obtained through the actual processing and test requirements.

[0090] Figure 11a The 32-unit rectangular array simulation effect diagram, namely the schematic diagram of the frequency response of the array return loss, is shown in the figure. As shown in Figure 11a , F1-F8 respectively represent the active standing waves of the eight linear arrays. According to Figure 11a , it can be seen that the values of the eight curves F1-F8 between the horizontal coordinates 18.7-20.2 GHz are below -14 dB; as shown in Figure 11b , the simulation gain at 18.7 GHz is greater than or equal to 24.3 dB.

[0091] At the frequency point 19.45 GHz, the intermediate frequency ideal gain of the 32-unit rectangular array (two-dimensional array) is 25 dB, but considering the dielectric loss and return loss, the actual intermediate frequency gain is reduced by 0.4 dB than the ideal intermediate frequency gain, and the total aperture efficiency of the array at this time reaches 85%, which is much higher than the aperture efficiency of other types of antennas (such as microstrip patch arrays) in the existing frequency band.

[0092] Figure 11c The main polarization and cross-polarization patterns of the intermediate frequency E plane and H plane of the 32-unit rectangular array are shown. Due to the excellent cross-polarization performance of the antenna unit, the cross-polarization ratio of the E plane and H plane of the arrayed antenna array is still greater than 30 dB.

[0093] Based on the air-backed cavity structure, the composite air-fed array antenna unit and the TCB low-loss feed network form the following 4*8 antenna linear array. In actual engineering applications, in view of the cost and weight, the machined metal radiation port layer is not used in the composite air-fed array, but the injection molding process is used, which is lighter in weight and lower in overall cost, so the side plate of the radiation port layer needs to be increased by a certain distance to ensure the structural strength of the radiation port layer. The other details of the radiation port layer model are also processed by chamfering process.

[0094] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0095] The above describes in detail the composite space-fed array antenna based on the three-dimensional circuit provided by the embodiment of the application. The principle and implementation manner of the application are described by using specific examples. The above embodiment is only used to help understand the technical solution of the application and its core idea. Those skilled in the art should understand that the technical solution recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and the modification or replacement does not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the application.

Claims

1. A composite air-fed array antenna based on a three-dimensional circuit, characterized in that, include: Flooring; An antenna layer is disposed on one side of the ground plane, and the antenna layer includes antenna elements; as well as A radiating port surface layer is disposed on the side of the antenna layer away from the ground plane. The radiating port surface layer includes radiating elements corresponding to the antenna elements, and each radiating element includes at least two radiating ports.

2. The composite air-fed array antenna based on a three-dimensional circuit according to claim 1, characterized in that, The geometric center of the antenna element, when projected onto the ground plane, coincides with the geometric center of the radiating element, when projected onto the ground plane.

3. The composite air-fed array antenna based on a three-dimensional circuit according to claim 1 or 2, characterized in that, The radiation port surface layer includes: A first side plate, two first side plates disposed opposite each other, and each first side plate extending along a first direction; and A connecting plate, which is connected between the two first side plates in a second direction and is located on the side away from the grounding plate; The connecting plate includes at least two spaced-apart radiation ports.

4. The composite air-fed array antenna based on a three-dimensional circuit according to claim 3, characterized in that, Each of the antenna elements includes: A dielectric plate includes a body and an air cavity, the air cavity protruding from the body in a third direction, the air cavity including a top surface and a sidewall located at the edge of the top surface; A metal patch is disposed on the top surface of the air cavity; and A metal guide strip is disposed on the side wall of the air cavity; In each of the antenna elements, the metal patch at least partially overlaps with the orthographic projection of the radiating port in each of the radiating elements onto the ground plane.

5. The composite air-fed array antenna based on a three-dimensional circuit according to claim 4, characterized in that, The geometric center of the metal patch in each antenna element, when projected onto the ground plane, coincides with the geometric center of the connecting plate in each radiating element, when projected onto the ground plane.

6. The composite air-fed array antenna based on a three-dimensional circuit according to claim 3, characterized in that, The distance between the end of the connecting plate and the end of the first side plate furthest from the ground plate is 1 to 3 mm.

7. The composite air-fed array antenna based on a three-dimensional circuit according to claim 3, characterized in that, In each of the said radiating elements, the radiating port surface layer further includes: The second side plate, two second side plates are arranged opposite each other, each second side plate is connected between the two first side plates in the second direction and is located at the end of the first side plate; The second side plate and the ends of the two first side plates fit together to form an opening.

8. The composite air-fed array antenna based on a three-dimensional circuit according to claim 7, characterized in that, In each of the radiating units, the connecting plate includes: A first connecting rib, which connects to the two second side plates in the first direction and is located between the two first side plates; and / or The second connecting rib connects between the two first side plates in the second direction and is located between the two second side plates.

9. The composite air-fed array antenna based on a three-dimensional circuit according to claim 1, characterized in that, The radiation port surface layer has a first dimension a in the second direction, where 0.25λ≤a≤0.45λ; The radiation port has a second dimension b in the first direction, where 0.4λ≤b≤0.6λ; Where λ is the wavelength corresponding to the center frequency of the antenna's operating frequency band.

10. The composite air-fed array antenna based on a three-dimensional circuit according to claim 1, characterized in that, The antenna element has a third dimension c in the first direction, where 1λ≤c≤2λ; The antenna element has a fourth dimension d in a third direction, where 0.45λ≤d≤0.55λ; Where λ is the wavelength corresponding to the center frequency of the antenna's operating frequency band.

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