Four-port wide-angle scanning phase-mode antenna and direction of arrival and polarization joint estimation method thereof

Abstract

The invention provides a four-port wide-angle scanning phase-mode antenna and a direction of arrival and polarization joint estimation method thereof. The four-port wide-angle scanning phase-mode antenna comprises a first dielectric plate, a second dielectric plate, a third dielectric plate, a fourth dielectric plate, a fifth dielectric plate, a sixth dielectric plate, a first connecting piece, a second connecting piece and four feed terminals, a feed structure and a floor are arranged on the first dielectric plate; a feed structure and a radiator are arranged on the second dielectric plate, the feed structure comprises a feed monopole antenna, the radiator comprises a first radiator located at the center of the dielectric plate and a tuning structure located at the edge of the dielectric plate, and the structures of the third dielectric plate, the fourth dielectric plate and the fifth dielectric plate are the same as those of the second dielectric plate. The antenna provided by the invention can realize full-airspace scanning of the upper hemispherical surface, and the estimation method can realize polarization state estimation of incoming wave signals.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, specifically to a four-port wide-angle scanning phase-mode antenna and its direction of arrival and polarization estimation method, and more specifically to a compact multi-polarization antenna suitable for the Wi-Fi band and its signal processing algorithm, which can be used in 5G / 6G smart antenna systems, radar target recognition and other scenarios. Background Technology

[0002] In modern wireless communication and radar detection technologies, phased array antennas are used for directivity control, multi-channel transceiver, and incoming signal direction detection. Directivity control of the array antenna is mainly achieved by adjusting the phase difference between each antenna. Multi-channel transceiver uses the isolation between ports to form independent transmit and receive channels. Incoming signal direction detection is achieved by creating different directivities within the array and resolving the incoming signal direction based on the sampling results of the receiving channel. Traditional phased array antennas, due to fixed element radiation, suffer from a trade-off between scanning angle, element spacing, and gain roll-off. Phase-mode antennas, however, allow for variable element radiation, thus resolving this trade-off with arrays using phase-mode antennas as units. A phase-mode antenna is an antenna where multiple ports share a radiating element. This type of antenna can independently control the phase of each port, achieving phase control directivity and multi-channel transceiver functionality on a single antenna. Compared to traditional antenna arrays, phase-mode antennas offer advantages such as improved aperture efficiency, reduced scanning gain roll-off, and lower sidelobe levels. The development of more types of phase-mode antennas and related functionalities is of great significance for improving the performance of antenna systems.

[0003] Direction finding algorithms based on traditional antennas and arrays mainly include the MUSIC algorithm and the amplitude comparison method. The MUSIC algorithm relies on a high signal-to-noise ratio (SNR) environment and is sensitive to array manifold errors. Lower SNR and antenna position offset errors both increase the direction finding error. Furthermore, the MUSIC algorithm is limited by the signal sampling rate, resulting in long computation time. The amplitude comparison method based on traditional antenna arrays has a large error and a small range. Compared to traditional amplitude comparison methods, the radiation diversity of phase-mode antenna elements eliminates the dependence on the array, significantly increases the direction finding range, and reduces errors. It also incorporates polarization estimation, thus avoiding the limitations of algorithms like the MUSIC algorithm while retaining the low complexity of the traditional amplitude comparison method. This solves the problems of high error and small range in traditional array-based amplitude comparison methods. This large-angle, low-error direction finding method based on phase-mode antennas is of great significance for improving incoming wave detection and estimation.

[0004] Patent document CN113311383A (application number: 202110479168.5) discloses a method for joint estimation of antenna direction finding and polarization parameters based on a rectangular array, which includes the following steps: establishing a mathematical model of a rectangular array antenna and obtaining the received data of the rectangular array; and estimating the incident signal DOA and polarization parameters based on the received data of the rectangular array. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a four-port wide-angle scanning phase-mode antenna and a method for estimating its direction of arrival and polarization.

[0006] A four-port wide-angle scanning phase mode antenna according to the present invention includes: a first dielectric substrate 21, a second dielectric substrate 31, a third dielectric substrate 32, a fourth dielectric substrate 33, a fifth dielectric substrate 34, a sixth dielectric substrate 5, a first connector 41, a second connector 42, and four feed terminals.

[0007] The upper surface of the first medium plate 21 is connected and fixed to the bottom surface of the second connector 42;

[0008] The lower surface of the sixth medium plate 5 is connected and fixed to the top surface of the first connector 41;

[0009] The first connector 41 and the second connector 42 are located between the first dielectric plate 21 and the sixth dielectric plate 5, and the first connector 41, the second connector 42, the first dielectric plate 21, and the sixth dielectric plate 5 are arranged in parallel.

[0010] The second medium plate 31, the third medium plate 32, the fourth medium plate 33, and the fifth medium plate 34 are respectively connected and fixed to the four sides of the first connector 41 and the second connector 42;

[0011] The second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33, and the fifth dielectric substrate 34 each include a radiator, namely a first radiator 316, a second radiator 326, a third radiator 336, and a fourth radiator 346; the first radiator 316, the second radiator 326, the third radiator 336, and the fourth radiator 346 are electrically connected to the ground plane 26 through multiple copper-clad vias; wherein, the ground plane 26 is located on the lower surface of the first dielectric substrate 21;

[0012] The sixth dielectric substrate 5 includes a fifth radiator 51, which is electrically connected to the first radiator 316, the second radiator 326, the third radiator 336 and the fourth radiator 346 respectively via copper foil patches.

[0013] The first dielectric substrate 21 includes a first matching feed microwire 22, a second matching feed microwire 23, a third matching feed microwire 24, and a fourth matching feed microwire 25;

[0014] The four power supply terminals pass through copper-free through holes and are electrically connected to the first matching power supply microwire 22, the second matching power supply microwire 23, the third matching power supply microwire 24, and the fourth matching power supply microwire 25, respectively.

[0015] After the radio frequency signals from the four feed terminals excite the electromagnetic field on the surface of the radiator, the radiation is emitted into space through the first radiator 316, the second radiator 326, the third radiator 336, the fourth radiator 346 and the fifth radiator 51.

[0016] Preferably, the outer contours of the first radiator 316, the second radiator 326, the third radiator 336 and the fourth radiator 346 are wavy, and strip-shaped grooves are made on both sides to form a comb-like structure.

[0017] The outer contour of the fifth radiator 51 is a cross shape composed of four triangles, and each triangle has a comb-like structure with strip-shaped slots.

[0018] Preferably, the first dielectric substrate 21 is square with a side length of 0.625 wavelengths of the operating frequency;

[0019] The second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33 and the fifth dielectric substrate 34 are all rectangular, with the long side being 0.33 wavelengths of the operating frequency and the short side being 0.22 wavelengths of the operating frequency.

[0020] The sixth dielectric substrate 5 is square with a side length of 0.33 wavelengths of operating frequency;

[0021] The second dielectric plate 31, the third dielectric plate 32, the fourth dielectric plate 33 and the fifth dielectric plate 34 are arranged in a central rotational symmetry with a rotation angle of 90°.

[0022] Preferably, the first dielectric substrate 21, the second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33, the fifth dielectric substrate 34, and the sixth dielectric substrate 5 are all manufactured using PCB technology.

[0023] The first dielectric substrate 21 has a thickness of 1.6 mm, a relative permittivity of 4.3, and a loss tangent of less than 0.025.

[0024] The thickness of the second dielectric plate 31, the third dielectric plate 32, the fourth dielectric plate 33, the fifth dielectric plate 34, and the sixth dielectric plate 5 is 1.524 mm, the relative permittivity is 2.6, and the loss tangent is less than 0.002.

[0025] All radiators, feed microwires, feed monopole antennas, and tuning structures are printed copper in PCB manufacturing processes.

[0026] Preferably, the first radiator 316, the second radiator 326, the third radiator 336, and the fourth radiator 346 are electrically connected to the ground plane 26 through multiple copper-plated vias, including: the first radiator 316, the second radiator 326, the third radiator 336, and the fourth radiator 346 are electrically connected to the ground plane 26 at equal intervals through multiple copper-plated vias.

[0027] The spacing between each copper-clad via is less than 0.1 wavelengths of the operating frequency.

[0028] According to the present invention, a method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna is provided, which performs the following steps using the aforementioned four-port wide-angle scanning phase-mode antenna:

[0029] Step S1: Based on the four-port large-angle scanning phase mode antenna, select multiple different combinations of phase differences between the four feed terminals to obtain radiation patterns with different main lobe directions;

[0030] Step S2: Calculate the corresponding polarization mismatch factor according to different polarization states, and use the corresponding polarization mismatch factor to correct the original radiation pattern to obtain the equivalent receiving gain pattern under different polarization states; among which, the different polarization states include horizontal polarization, vertical polarization, ±45° linear polarization, left circular polarization and right circular polarization.

[0031] Step S3: Based on the equivalent receiving gain pattern under different polarization states, establish the mapping relationship between the received level amplitude under different incoming wave directions and polarization states and the corresponding equivalent gain pattern;

[0032] Step S4: Based on the mapping relationship of the received level amplitude, the actual received level amplitude is obtained by using the four-port large-angle scanning phase mode antenna to the four feed terminals with the selected phase difference combination. The received level amplitude is then reverse-mapped according to the mapping relationship of the received level amplitude to estimate the direction of arrival and polarization state.

[0033] Preferably, step S1 includes:

[0034] Based on the aforementioned four-port large-angle scanning phase-mode antenna, the radiation pattern of the antenna element is changed by altering the phase difference combination of the four feed terminals, selecting multiple radiation patterns at different angles of the main lobe direction; the gain pattern function of the antenna element is... G represents the antenna gain at different angles, and θ represents the elevation angle. For azimuth, use The elevation angle, azimuth angle, and polarization state estimation parameters represent the direction of arrival of the wave; all selected radiation patterns are numbered 1, 2, ..., N. Record and save all feed port phase difference combinations, numbered 1, 2, ..., N, and φ. k =[Δφ 1,k ,Δφ 2,k ,Δφ 3,k ], k = 1, 2, ..., N.

[0035] Preferably, step S2 includes:

[0036] The equivalent receiver gain pattern is calculated for each polarization state. The equivalent receiver gain pattern is as follows: in, Polarization mismatch factor The polarization vector of the transmitted signal. Let be the polarization vector of the radiation pattern at different angles, and p be the different polarization states.

[0037] Preferably, step S3 includes:

[0038] Based on the equivalent receiver gain patterns under different polarization states, the equivalent gain patterns for each polarization correction are paired up. The equivalent gain pattern ratio is obtained by comparing the values ​​of each pair of cooperative ratios. This represents the i-th equivalent receiver gain pattern; This represents the j-th equivalent receive gain pattern; the ratio of the received level amplitude at different angles is... in, To obtain the actual received level amplitude under the corresponding port phase difference combination under the equivalent gain pattern; the difference function is obtained by subtracting the equivalent gain pattern ratio from the actual received level amplitude ratio. achievable

[0039] Preferably, step S4 includes: using the four-port large-angle scanning phase-mode antenna, obtaining the received signal amplitude under the N phase difference combinations obtained in step S1 using a spectrum analyzer, and obtaining the corresponding predicted values ​​of the incoming wave direction respectively. and the minimum difference of all polarization cases Then find the polarization state corresponding to the minimum difference among all polarization cases. Finally, the estimation results were obtained.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. This invention achieves large-angle scanning and polarization control of the main lobe direction of a single antenna through a unified multi-port design, a rotationally symmetric structure design relative to multiple ports, and a phase difference applied to multiple ports;

[0042] 2. This invention improves the isolation between feed ports by connecting the four feed microstrip lines and the corresponding four feed monopole antennas;

[0043] 3. This invention increases the resonant bandwidth of the antenna by designing a tuning structure;

[0044] 4. The present invention improves the port isolation of the antenna by connecting the ground plane and the radiator through a via.

[0045] 5. This invention achieves large-angle scanning of the upper hemisphere by designing a three-dimensionally distributed radiator structure and combining it with phase control of the ports;

[0046] 6. Compared with subspace decomposition combined with spectral peak search methods such as the MUSIC algorithm, this invention significantly reduces computational complexity, reduces the delay time for wave direction estimation, and improves the real-time performance of the estimation.

[0047] 7. Compared with the traditional amplitude comparison method, this invention combines a four-port large-angle two-dimensional scanning phase-mode antenna to realize the extended application of direction finding from one-dimensional to two-dimensional, and improves the direction finding accuracy under low elevation angle conditions.

[0048] 8. Compared with algorithms such as the MUSIC algorithm, this invention no longer relies on antenna arrays. It can estimate the direction of arrival and polarization state of incident waves on the upper hemisphere using only the four-port large-angle two-dimensional scanning phase mode antenna provided by this invention.

[0049] 9. Compared with the traditional amplitude comparison method, this invention not only realizes two-dimensional spatial scanning of the upper hemisphere, but also realizes polarization state estimation of the incoming wave signal. At the same time, the method for estimating the direction of arrival and polarization state of the upper hemisphere based on a four-port large-angle two-dimensional scanning antenna element using only received level amplitude information shows significant application advantages and potential in the field of radar target recognition and scanning technology.

[0050] 10. Based on the phase-mode antenna, this invention selects different radiation patterns as the basis for incoming wave characteristic analysis, establishes a channel environment including the incoming wave signal and the phase-mode antenna receiving unit, and obtains the incoming wave direction and polarization information of the received signal through a peak search method. Attached Figure Description

[0051] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0052] Figure 1This is an exploded view of the four-port phase-mode antenna of Example 1.

[0053] Figure 2 This is a top plan view of the first dielectric substrate in Embodiment 1.

[0054] Figure 3 This is a bottom plan view of the first dielectric substrate in Embodiment 1.

[0055] Figure 4 This is a top plan view of the second dielectric substrate in Embodiment 1.

[0056] Figure 5 This is a bottom plan view of the second dielectric substrate in Embodiment 1.

[0057] Figure 6 This is a plan view of the sixth dielectric substrate in Example 1.

[0058] Figure 7 This is a plan view of the first connector in Embodiment 1.

[0059] Figure 8 This is a plan view of the second connector in Embodiment 1.

[0060] Figure 9 This is a schematic diagram of the hierarchical structure of the first dielectric substrate in Embodiment 1.

[0061] Figure 10 This is a schematic diagram of the assembled four-port phase-mode antenna of Embodiment 1.

[0062] Figure 11 The simulation and measured S-parameter diagrams of the four-port phase-mode antenna in Example 1 are shown.

[0063] Figure 12 This is a flowchart of the direction finding method based on a four-port large-angle two-dimensional scanning phase-mode antenna in Example 2.

[0064] Figure 13 This is a diagram showing the direction-finding environment setup for a four-port large-angle two-dimensional scanning phase-mode antenna in Example 2.

[0065] Figure 14 This is a scatter plot of the incoming wave direction estimation error of the direction finding method based on a four-port large-angle two-dimensional scanning phase-mode antenna in Example 2.

[0066] Figure 15 This is a heatmap showing the polarization state estimation accuracy of the direction finding method based on a four-port large-angle two-dimensional scanning phase-mode antenna in Example 2.

[0067] The diagram shows:

[0068] First feed terminal 11 Second dielectric board 31

[0069] First inner conductor 111; First tuning structure 312 to 315

[0070] First feed terminal dielectric 112 First radiator 316

[0071] First outer conductor 113 First fed monopole antenna 317

[0072] Second feed terminal 12 Third dielectric board 32

[0073] Second inner conductor 121; Second tuning structure 322 to 325

[0074] Second feed terminal dielectric 122 Second radiator 326

[0075] Second outer conductor 123 Second fed monopole antenna 327

[0076] Third feed terminal 13 Fourth dielectric board 33

[0077] Third inner conductor 131; Third tuning structure 332 to 335

[0078] Third feed terminal dielectric 132 Third radiator 336

[0079] Third outer conductor 133 Third-fed monopole antenna 337

[0080] Fourth feed terminal 14 Fifth dielectric board 34

[0081] Fourth inner conductor 141; Fourth tuning structure 342 to 345

[0082] Fourth feed terminal dielectric 142 Fourth radiator 346

[0083] Fourth outer conductor 143, fourth-fed monopole antenna 347

[0084] First medium plate 21 First connector 41

[0085] First feed microstrip line 22 Second connector 42

[0086] Second feed microstrip line 23 Nylon screws 4301 to 4324

[0087] Third feed microstrip line 24, sixth dielectric substrate 5

[0088] Fourth feed microstrip line 25, fifth radiator 51

[0089] Floor joint 26, connecting patches 53 to 56

[0090] 6 copper-clad through-holes

[0091] Copper-free through-hole 7 Detailed Implementation

[0092] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0093] Example 1

[0094] A four-port wide-angle scanning phase mode antenna according to the present invention includes: a first dielectric substrate 21, a second dielectric substrate 31, a third dielectric substrate 32, a fourth dielectric substrate 33, a fifth dielectric substrate 34, a sixth dielectric substrate 5, a first connector 41, a second connector 42, and four feed terminals.

[0095] The four-port wide-angle scanning phase-mode antenna is arranged from bottom to top as a bottom layer, a middle layer, and a top layer, wherein:

[0096] The bottom layer is provided with the first dielectric plate 21;

[0097] The intermediate layer is provided with a second dielectric plate 31, a third dielectric plate 32, a fourth dielectric plate 33 and a fifth dielectric plate 34, and the rotation angle between adjacent structures is 90°;

[0098] The top layer is provided with the sixth medium plate 5, whose projection position coincides with the center of the first medium plate 21.

[0099] The first dielectric substrate 21 is provided with a power supply structure and a ground plane. The power supply structure is on the upper surface of the first dielectric substrate 21, and the ground plane is on the lower surface of the first dielectric substrate 21. The power supply structure includes four power supply microstrip lines 22-25.

[0100] The second dielectric substrate 31 is provided with a feeding structure and a radiator. The feeding structure includes a fed monopole antenna 317, and the radiator includes a first radiator 316 located at the center of the dielectric substrate and a tuning structure 312-315 located at the edge of the dielectric substrate. The structures of the third dielectric substrate 32, the fourth dielectric substrate 33 and the fifth dielectric substrate 34 are the same as those of the second dielectric substrate 31.

[0101] The tuning structure 312-315 consists of four rectangular patches of the same size, located on both sides of the front and back edges of the second dielectric substrate 31, respectively.

[0102] The first to fourth radiators are electrically connected to the ground plane, and the four feed terminals are respectively connected to the four feed microstrip lines 22-25. The four feed microstrip lines 22-25 are respectively electrically connected to the four feed monopole antennas 317, 327, 337, and 347.

[0103] The sixth dielectric plate 5 is provided with a fifth radiator 51 and connecting patches 53-56, and the connecting patches are electrically connected to the first to fourth radiators respectively.

[0104] The fed monopole antenna feeds the radiator through coupling; after the radio frequency signals from the four feeding terminals excite the electromagnetic field on the surface of the radiator, the field is radiated into space through the radiator composed of the first to fifth radiators.

[0105] The first connector 41 is provided with 12 rotationally symmetrically distributed through holes, which are connected and fixed to the second medium plate 31, the third medium plate 32, the fourth medium plate 33, the fifth medium plate 34 and the sixth medium plate 5 by nylon screws 4301-4312.

[0106] The second connector 42 is provided with 12 rotationally symmetrically distributed through holes, which are connected and fixed to the first medium plate 2, the second medium plate 31, the third medium plate 32, the fourth medium plate 33 and the fifth medium plate 34 by nylon screws 4313-4324.

[0107] Specifically, all four of the aforementioned feed microstrip lines 22-25 are strip-shaped;

[0108] The four feed microstrip lines are arranged in a rotationally symmetrical manner, and the outer contour of the four microstrip line structures is a square, with an angle of 0° between the square contour of the first dielectric substrate 21 and the square contour of the first dielectric substrate 21.

[0109] Specifically, the first radiator 316 is a wavy radiating patch with a dressing strip-shaped groove;

[0110] The outer contour of the first radiator 316 is wavy.

[0111] Specifically, all four fed monopole antennas are rectangular patches;

[0112] The four patch antennas are arranged parallel to the edge of the dielectric substrate.

[0113] Specifically, the tuning structure consists of four rectangular patches located on both sides of the front and back edges of the dielectric substrate; the dielectric substrate here includes: a second dielectric substrate 31, a third dielectric substrate 32, a fourth dielectric substrate 33, and a fifth dielectric substrate 34;

[0114] The tuning structure consists of symmetrically arranged rectangular patches.

[0115] Specifically, the fifth radiator is a cross-shaped triangular radiating patch with a dressing strip groove;

[0116] The outer contour of the fifth radiator is a cross-shaped structure with triangular edges.

[0117] Specifically, the first to sixth dielectric substrates together form a rectangular antenna structure;

[0118] The outer contour of the four-port phase-mode antenna is rectangular.

[0119] Specifically, the grounding plate has a square structure.

[0120] Specifically, the first dielectric substrate 21 is square with a side length of 0.625 wavelengths of operating frequency;

[0121] The second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33 and the fifth dielectric substrate 34 are all rectangular, with the long side being 0.33 wavelengths of the operating frequency and the short side being 0.22 wavelengths of the operating frequency.

[0122] The sixth dielectric substrate 5 is square with a side length of 0.33 wavelengths of operating frequency;

[0123] Specifically, the outer conductors of all four power supply terminals are connected to the ground plane;

[0124] The inner conductors of the four feed terminals are respectively connected to the four feed monopole antennas.

[0125] Specifically, the first radiator 316 to the fourth radiator 346 are electrically connected to the ground plane through a plurality of copper-clad vias 6;

[0126] Multiple copper-clad vias 6 are distributed on the four sides of the four feed microstrip lines 22-25 of the first dielectric substrate 21, and are electrically connected to the ground plane at equal intervals.

[0127] Specifically, the spacing of the copper-clad vias 6 is less than 0.1 wavelengths of the operating frequency.

[0128] Specifically, the first dielectric board 21 to the sixth dielectric board 5 are all PCB boards;

[0129] The sixth dielectric plate 5 is connected to the second dielectric plate 31 to the fifth dielectric plate 34 respectively through four rectangular copper sheets;

[0130] The first dielectric substrate 21 has a thickness of 1.6 mm, a dielectric constant of 4.3, and a loss tangent of less than 0.025. The second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33, the fifth dielectric substrate 34, and the sixth dielectric substrate 5 all have a thickness of 1.524 mm and a loss tangent of less than 0.002.

[0131] A method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna according to the present invention includes: performing the following steps using the four-port wide-angle scanning phase-mode antenna:

[0132] Step 1: Select different combinations of phase differences between the four feed terminals of multiple four-port phase mode antennas to obtain radiation patterns with different main lobe directions;

[0133] Step 2: Based on Step 1, calculate the corresponding polarization mismatch factor according to different polarization states, and use this to correct the original radiation pattern to obtain the equivalent receiving gain pattern under different polarization states; among which, the different polarization states include: horizontal polarization, vertical polarization, ±45° linear polarization, left-hand circular polarization and right-hand circular polarization.

[0134] Step 3: Based on the equivalent receiving gain patterns under different polarization states obtained in Step 2, establish a mapping relationship between the received level amplitude under different incoming wave directions and polarization states and the corresponding equivalent gain patterns.

[0135] Step 4: Based on the mapping relationship obtained in Step 3, and using the four-port phase mode antenna, the actual received level amplitude is obtained by using the corresponding phase difference combination selected in Step 1 for the four feed terminals. Then, the inverse mapping is performed based on the mapping relationship obtained in Step 3 to estimate the outgoing wave direction and polarization state.

[0136] Step 1 includes:

[0137] The four-port wide-angle scanning phase-mode antenna provided by this invention can change the radiation pattern of the antenna element by altering the phase difference combination of the four feed terminals, selecting multiple radiation patterns at different angles of the main lobe direction; the gain pattern function of the antenna element is... G represents the antenna gain at different angles, and θ represents the elevation angle, i.e., the angle between the radius vector and the Oz axis. The azimuth angle is the angle between the projection of the radius vector onto the xOy plane and the Ox axis. The elevation angle, azimuth angle, and polarization state estimation parameters represent the direction of incoming waves.

[0138] Step 2 includes:

[0139] The equivalent receiver gain pattern is calculated for each of the following polarization states: horizontal polarization, vertical polarization, ±45° linear polarization, left-hand circular polarization, and right-hand circular polarization. The equivalent gain pattern is as follows: in Polarization mismatch factor The polarization vector of the transmitted signal. Let be the polarization vector of the radiation pattern at different angles, and p be the different polarization states.

[0140] Step 3 includes:

[0141] Based on the equivalent receiver gain patterns obtained in step 2 under different polarization states, each polarization-corrected equivalent gain pattern is grouped together, and the ratio of each pair of groups is used to obtain the equivalent gain pattern ratio. The ratio of received level amplitude at different angles is in This represents the actual received level amplitude under the corresponding port phase difference combination under the equivalent gain pattern. The difference function is obtained by subtracting the equivalent gain pattern ratio from the actual received level amplitude ratio. achievable

[0142] Step 4 includes:

[0143] Using the four-port wide-angle scanning phase-mode antenna provided by this invention, based on all the corresponding received level amplitudes obtained when selecting the radiation pattern in all steps 1, and substituted with different polarization conditions, the corresponding predicted values ​​of the incoming wave direction are obtained respectively. and the minimum difference of all polarization cases Then find the polarization state corresponding to the minimum difference among all polarization cases. Finally, the estimation results were obtained.

[0144] Example 2

[0145] Example 2 is a preferred example of Example 1.

[0146] like Figure 1-10 As shown, this embodiment provides a four-port wide-angle scanning phase mode antenna, including: a first dielectric substrate 21, a second dielectric substrate 31, a third dielectric substrate 32, a fourth dielectric substrate 33, a fifth dielectric substrate 34, a sixth dielectric substrate 5, a first connector 41, a second connector 42, and four feed terminals;

[0147] The bottom surface of the first dielectric plate 21 is connected and fixed to the second connector 42 by nylon screws 4313 to 4316. The four sides of the second dielectric plate 31, third dielectric plate 32, fourth dielectric plate 33, and fifth dielectric plate 34 are connected and fixed to the second connector 42 by nylon screws 4317 to 4324. The four sides of the second dielectric plate 31, third dielectric plate 32, fourth dielectric plate 33, and fifth dielectric plate 34 are connected and fixed to the first connector 41 by nylon screws 4305 to 4312. The top surface of the sixth dielectric plate 5 is connected and fixed to the first connector 41 by nylon screws 4301 to 4304. A matching power supply structure is provided on the first dielectric plate 21, which includes four microstrip lines 22 to 25. The second dielectric plate 31, third dielectric plate 32, fourth dielectric plate 33, and fifth dielectric plate 34 have the same structure and are centrally rotate symmetrically distributed. Each dielectric plate contains a radiator. A fed monopole antenna and four rectangular strip-shaped tuning structures are included. The first connector 41 and the second connector 42 are located between the first dielectric substrate 21 and the sixth dielectric substrate 5, forming a square structure surrounded by the second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33, and the fifth dielectric substrate 34. The first radiator 316, the second radiator 326, the third radiator 336, and the fourth radiator 346 are electrically connected to the ground plane 26 through copper-clad vias 6. The fifth radiator is electrically connected to the first radiator 316, the second radiator 326, the third radiator 336, and the fourth radiator 346 through copper foil patches 52 to 56, respectively. The four feed terminals pass through copper-free vias 7 and are electrically connected to the four matched feed microstrip lines 22 to 25 on the first dielectric substrate 21, respectively. After the radio frequency signal from the four feed terminals excites the electromagnetic field on the surface of the radiator, its radiation is radiated into space through radiators 1 to 5.

[0148] In this embodiment, the four feed terminals are the first feed terminal 11, the second feed terminal 12, the third feed terminal 13, and the fourth feed terminal 14, respectively; the four matching feed microstrip lines are the first feed microstrip line 22, the second feed microstrip line 23, the third feed microstrip line 24, and the fourth feed microstrip line 25, respectively; and the four feed monopole antennas are the first feed monopole antenna 317, the second feed monopole antenna 327, the third feed monopole antenna 337, and the fourth feed monopole antenna 347, respectively.

[0149] In this embodiment, the outer conductors of the four feed terminals are the first outer conductor 113, the second outer conductor 123, the third outer conductor 133, and the fourth outer conductor 143, respectively. The inner conductors of the four feed terminals are the first inner conductor 111, the second inner conductor 121, the third inner conductor 131, and the fourth inner conductor 141, respectively. The outer conductors of the four feed terminals are all connected to the ground plane 26, and the inner conductors of the four feed terminals are respectively connected to the four feed patch antennas.

[0150] In this embodiment, the four feed microstrip lines are electrically connected to the four feed monopole antennas via soldering.

[0151] In this embodiment, the first radiator 316, the second radiator 326, the third radiator 336, and the fourth radiator 346 are electrically connected to the ground plane 26 through multiple copper vias 6. The copper vias 6 are distributed on the four sides of the four matching feed microstrip lines and are electrically connected to the ground plane 26 at equal intervals. The spacing between the copper vias 6 is less than 0.1 wavelengths of the operating frequency.

[0152] In this embodiment, the fifth radiator 51 is electrically connected to the first radiator 316, the second radiator 326, the third radiator 336 and the fourth radiator 346 via copper foil connecting patches 53 to 56.

[0153] In this embodiment, the outer contours of the first radiator 316, the second radiator 326, the third radiator 336 and the fourth radiator 346 are wavy, with strip-shaped slots on both sides, forming a comb-like structure; the outer contour of the fifth radiator 51 is a cross shape composed of four triangles, with each triangle having strip-shaped slots to form a comb-like structure.

[0154] In this embodiment, the first medium plate 21, the second medium plate 31, the third medium plate 32, the fourth medium plate 33, the fifth medium plate 34, and the sixth medium plate 5 are all drilled at the corresponding openings of the first connector 41 and the second connector 42 for the installation and fixing of nylon screws.

[0155] In this embodiment, the first dielectric substrate 21, the second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33, the fifth dielectric substrate 34, and the sixth dielectric substrate 5 are all manufactured using PCB technology. The first dielectric substrate 21 has a thickness of 1.6 mm, a relative permittivity of 4.3, and a loss tangent of less than 0.025. The second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33, the fifth dielectric substrate 34, and the sixth dielectric substrate 5 all have a thickness of 1.524 mm, a relative permittivity of 2.6, and a loss tangent of less than 0.002. In this embodiment, all radiators, fed microstrip lines, fed monopole antennas, and tuning structures are printed copper in PCB technology.

[0156] Furthermore, the first dielectric substrate 21 is square with a side length of 0.625 wavelengths of operating frequency; the second dielectric substrate 31, the third dielectric substrate 32, the fourth dielectric substrate 33 and the fifth dielectric substrate 34 are all rectangular with a long side length of 0.33 wavelengths of operating frequency and a short side length of 0.22 wavelengths of operating frequency; the sixth dielectric substrate 5 is square with a side length of 0.33 wavelengths of operating frequency.

[0157] Furthermore, the entire antenna has a rotationally symmetric structure with a rotation angle of 90°.

[0158] like Figure 11 As shown, through simulation calculations and experimental tests, the operating frequency band of the four-port large-angle two-dimensional scanning phase mode antenna in this embodiment is 2.01-3.21GHz.

[0159] Example 3

[0160] Example 3 is a preferred example of Example 1.

[0161] like Figure 12 and Figure 13 As shown, taking a typical direction-finding environment as an example, the specific parameter settings are as follows: the incoming signal is set to a single-frequency signal of 2.5 GHz, the transmit power is -40 dBm, the transmit and receive distance is 5 m, and the receive signal-to-noise ratio is 10 dB. The signals are transmitted from the upper hemisphere of the antenna reference frame (θ: 0~90°). An incident light source (0–360°) is irradiated in a direction such as horizontal polarization, vertical polarization, ±45° linear polarization, left-handed circular polarization, or right-handed circular polarization. For example... Figure 12 As shown, the specific implementation process of this embodiment is as follows:

[0162] First, according to the four-port large-angle scanning phase-mode antenna element provided by the present invention, the radiation pattern of the antenna element can be changed by altering the phase difference combination of the four feed terminals, selecting multiple radiation patterns at different angles of the main lobe direction. The synthesized gain distribution function is... G represents the antenna gain at different angles, and θ represents the elevation angle, i.e., the angle between the radius vector and the Oz axis. The azimuth angle is the angle between the projection of the radius vector onto the xOy plane and the Ox axis. The elevation angle, azimuth angle, and polarization state estimation parameters represent the direction of arrival of the wave. All selected radiation patterns are numbered 1, 2, ..., N. It also records and saves all the phase difference combinations of the feed ports, numbered 1, 2, ..., N, and φ. k =[Δφ 1,k ,Δφ 2,k ,Δφ 3,k ], k = 1, 2, ..., N.

[0163] The second step, based on the first step, involves calculating the corresponding equivalent receiver gain pattern for different polarization states: horizontal polarization, vertical polarization, ±45° linear polarization, left-hand circular polarization, and right-hand circular polarization. The equivalent gain pattern is as follows: in Polarization mismatch factor The polarization vector of the transmitted signal. Let be the polarization vector of the radiation pattern at different angles, and p be the different polarization states.

[0164] The third step involves pairing the equivalent receiver gain patterns obtained in the second step under different polarization states. The equivalent gain pattern ratio is obtained by comparing the values ​​of each pair of cooperative ratios. The ratio of received level amplitude at different angles is in This represents the actual received level amplitude under the corresponding port phase difference combination under the equivalent gain pattern. The difference function is obtained by subtracting the equivalent gain pattern ratio from the actual received level amplitude ratio. achievable

[0165] The fourth step involves using the four-port large-angle scanning phase-mode antenna unit provided by this invention to obtain the received signal amplitude under the N phase difference combinations obtained in the first step using a spectrum analyzer, and then obtaining the corresponding predicted values ​​of the incoming wave direction. and the minimum difference of all polarization cases Then find the polarization state corresponding to the minimum difference among all polarization cases. Finally, the estimation results were obtained.

[0166] Figure 14 The incident angle is given as θ = 0 to 90°. The step size of θ is 5°. The root mean square error distribution for each angle of the incoming wave signal with six polarizations (horizontal, vertical, ±45° linear, left-hand circular, and right-hand circular) is shown with a step size of 15°. It can be seen that, with an SNR of 10dB, the overall hemispherical direction finding error is less than 2.6°, with the maximum error occurring at θ = 85°. With an error of 2.6°, the direction finding method in this embodiment has higher accuracy than the traditional amplitude comparison method, and the direction finding dimension is expanded from one dimension to two dimensions, achieving higher accuracy direction finding in the upper hemisphere.

[0167] Figure 15 The incident angle is given as θ = 0 to 90°. The step size of θ is 5°. A heatmap showing the polarization estimation accuracy at each angle for incoming signals with six polarizations (horizontal, vertical, ±45° linear, left-hand circular, and right-hand circular) with a step size of 15°. It can be seen that, with an SNR of 10dB, the estimation accuracy for all six different polarizations is above 99%.

[0168] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0169] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A four-port wide-angle scanning phase-mode antenna, characterized in that, include: The first dielectric board (21), the second dielectric board (31), the third dielectric board (32), the fourth dielectric board (33), the fifth dielectric board (34), the sixth dielectric board (5), the first connector (41), the second connector (42), and four power supply terminals; The upper surface of the first medium plate (21) is connected and fixed to the bottom surface of the second connector (42); The lower surface of the sixth medium plate (5) is fixedly connected to the top surface of the first connector (41); The first connector (41) and the second connector (42) are located between the first medium plate (21) and the sixth medium plate (5), and the first connector (41), the second connector (42), the first medium plate (21), and the sixth medium plate (5) are arranged in parallel. The second medium plate (31), the third medium plate (32), the fourth medium plate (33), and the fifth medium plate (34) are respectively connected and fixed to the four sides of the first connector (41) and the second connector (42); The second dielectric substrate (31), the third dielectric substrate (32), the fourth dielectric substrate (33), and the fifth dielectric substrate (34) each include a radiator, namely a first radiator (316), a second radiator (326), a third radiator (336), and a fourth radiator (346); the first radiator (316), the second radiator (326), the third radiator (336), and the fourth radiator (346) are electrically connected to the ground plane (26) through multiple copper-clad vias; wherein, the ground plane (26) is located on the lower surface of the first dielectric substrate (21); The sixth dielectric substrate (5) includes a fifth radiator (51), which is electrically connected to the first radiator (316), the second radiator (326), the third radiator (336) and the fourth radiator (346) respectively via copper foil patches; The first dielectric substrate (21) includes a first matching feed microwire (22), a second matching feed microwire (23), a third matching feed microwire (24), and a fourth matching feed microwire (25); The four power supply terminals pass through copper-free through holes and are electrically connected to the first matching power supply microwire (22), the second matching power supply microwire (23), the third matching power supply microwire (24), and the fourth matching power supply microwire (25), respectively. After the radio frequency signals from the four feed terminals excite the electromagnetic field on the surface of the radiator, the radiation is radiated into space through the first radiator (316), the second radiator (326), the third radiator (336), the fourth radiator (346) and the fifth radiator (51).

2. The four-port wide-angle scanning phase-mode antenna according to claim 1, characterized in that, The outer contours of the first radiator (316), the second radiator (326), the third radiator (336) and the fourth radiator (346) are wavy, with strip-shaped grooves on both sides, forming a comb-like structure as a whole; The outer contour of the fifth radiator (51) is a cross shape composed of four triangles, and each triangle is slotted in a strip to form a comb-like structure.

3. The four-port wide-angle scanning phase-mode antenna according to claim 1, characterized in that, The first dielectric substrate (21) is square with a side length of 0.625 wavelengths of operating frequency; The second dielectric substrate (31), the third dielectric substrate (32), the fourth dielectric substrate (33) and the fifth dielectric substrate (34) are all rectangular, with the long side being 0.33 wavelengths of the working frequency and the short side being 0.22 wavelengths of the working frequency; The sixth dielectric plate (5) is square with a side length of 0.33 wavelengths of operating frequency; The second dielectric plate (31), the third dielectric plate (32), the fourth dielectric plate (33) and the fifth dielectric plate (34) are arranged in a central rotational symmetry with a rotation angle of 90°.

4. The four-port wide-angle scanning phase-mode antenna according to claim 1, characterized in that, The first dielectric board (21), the second dielectric board (31), the third dielectric board (32), the fourth dielectric board (33), the fifth dielectric board (34), and the sixth dielectric board (5) are all made using PCB technology; The first dielectric substrate (21) has a thickness of 1.6 mm, a relative permittivity of 4.3, and a loss tangent of less than 0.

025. The thickness of the second dielectric plate (31), the third dielectric plate (32), the fourth dielectric plate (33), the fifth dielectric plate (34), and the sixth dielectric plate (5) is 1.524 mm, the relative permittivity is 2.6, and the loss tangent is less than 0.

002. All radiators, feed microwires, feed monopole antennas, and tuning structures are printed copper in PCB manufacturing processes.

5. The four-port wide-angle scanning phase-mode antenna according to claim 1, characterized in that, The first radiator (316), the second radiator (326), the third radiator (336), and the fourth radiator (346) are electrically connected to the ground plane (26) through multiple copper-plated vias, including: the first radiator (316), the second radiator (326), the third radiator (336), and the fourth radiator (346) are electrically connected to the ground plane (26) at equal distances through multiple copper-plated vias; The spacing between each copper-clad via is less than 0.1 wavelengths of the operating frequency.

6. A method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna, characterized in that, The following steps are performed using the four-port wide-angle scanning phase-mode antenna according to any one of claims 1 to 5: Step S1: Based on the four-port large-angle scanning phase mode antenna, select multiple different combinations of phase differences between the four feed terminals to obtain radiation patterns with different main lobe directions; Step S2: Calculate the corresponding polarization mismatch factor according to different polarization states, and use the corresponding polarization mismatch factor to correct the original radiation pattern to obtain the equivalent receiving gain pattern under different polarization states; among which, the different polarization states include horizontal polarization, vertical polarization, ±45° linear polarization, left circular polarization and right circular polarization. Step S3: Based on the equivalent receiving gain pattern under different polarization states, establish the mapping relationship between the received level amplitude under different incoming wave directions and polarization states and the corresponding equivalent gain pattern; Step S4: Based on the mapping relationship of the received level amplitude, the actual received level amplitude is obtained by using the four-port large-angle scanning phase mode antenna to the four feed terminals with the selected phase difference combination. The received level amplitude is then reverse-mapped according to the mapping relationship of the received level amplitude to estimate the direction of arrival and polarization state.

7. The method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna according to claim 6, characterized in that, Step S1 includes: Based on the aforementioned four-port large-angle scanning phase-mode antenna, the radiation pattern of the antenna element is changed by altering the phase difference combination of the four feed terminals, selecting multiple radiation patterns at different angles of the main lobe direction; the gain pattern function of the antenna element is... G represents the antenna gain at different angles, and θ represents the elevation angle. For azimuth, use The elevation angle, azimuth angle, and polarization state estimation parameters represent the direction of arrival of the wave; all selected radiation patterns are numbered 1, 2, ..., N. Record and save all feed port phase difference combinations, numbered 1, 2, ..., N, and φ. k =[Δφ 1,k ,Δφ 2,k ,Δφ 3,k ], k = 1, 2, ..., N.

8. The method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna according to claim 7, characterized in that, Step S2 includes: The equivalent receiver gain pattern is calculated for each polarization state. The equivalent receiver gain pattern is as follows: in, Polarization mismatch factor The polarization vector of the transmitted signal. Let be the polarization vector of the radiation pattern at different angles, and p be the different polarization states.

9. The method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna according to claim 7, characterized in that, Step S3 includes: Based on the equivalent receiver gain patterns under different polarization states, the equivalent gain patterns for each polarization correction are paired up. The equivalent gain pattern ratio is obtained by comparing the values ​​of each pair of cooperative ratios. This represents the i-th equivalent receiver gain pattern; This represents the j-th equivalent receive gain pattern; the ratio of the received level amplitude at different angles is... in, To obtain the actual received level amplitude under the corresponding port phase difference combination under the equivalent gain pattern; the difference function is obtained by subtracting the equivalent gain pattern ratio from the actual received level amplitude ratio. achievable 10. The method for co-estimating the direction of arrival and polarization of a four-port wide-angle scanning phase-mode antenna according to claim 9, characterized in that, Step S4 includes: using the four-port large-angle scanning phase-mode antenna, obtaining the received signal amplitude under the N phase difference combinations obtained in step S1 using a spectrum analyzer, and obtaining the corresponding predicted values ​​of the incoming wave direction respectively. and the minimum difference of all polarization cases Then find the polarization state corresponding to the minimum difference among all polarization cases. Finally, the estimation results were obtained.

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