A co-frequency, co-polarization, and co-aperture antenna with high isolation and low correlation

Abstract

The present invention discloses a co-frequency and co-polarization common aperture antenna with high isolation and low correlation, belonging to the technical field of microwave millimeter wave antennas. The co-frequency and co-polarization common aperture antenna is composed of a reflective floor and a radiation patch printed on a first dielectric substrate and a second dielectric substrate, an odd-mode feeding network, and a differential-mode feeding network. The overlapping operating frequency bands of the two ports of the co-frequency and co-polarization common aperture antenna are 3.46-4.18 GHz or 5.46-6.18 GHz; the in-band reflection coefficient is less than ‑10 dB, the peak gains of the two ports in the band are greater than 6.3 dB and 6.87 dB, respectively, the port isolation of the two ports in the band is greater than 21.27 dB and 18.56 dB, respectively, and the correlation coefficient is less than 0.002. The present invention utilizes the orthogonality between the two groups of modes on the radiation patch, so that the two sets of feeding networks can achieve the co-polarization upper half-space radiation pattern while ensuring high isolation and low correlation between the ports. The present invention is suitable for outdoor macro base stations of mobile communication systems, especially miniaturized and compact outdoor large-scale MIMO arrays.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave antennas, and in particular relates to a same-frequency-band co-planar and co-aperture base station antenna in a microwave antenna. Background Art

[0002] Massive multiple-input multiple-output (MIMO) arrays are the main development trend of the new generation of base station antennas. A notable feature of massive MIMO arrays is the sharp increase in the number of array units, which generally include hundreds or even thousands of units. However, due to the limitations of practical requirements such as wind force, weight, packaging and cost, outdoor base station antennas must have the characteristics of integration, miniaturization, lightweight and low cost. In order to meet the above requirements, multi-port side-firing array unit antennas have become a hot topic of research in recent years. The performance of multi-port side-firing antenna units can meet the requirements of the side-firing radiation pattern required by outdoor base stations, and at the same time, it can reduce the size of the array and reduce the cost while ensuring that the number of array ports remains unchanged. In particular, this provides an effective way to reduce the production cost and lightweight of low-frequency massive MIMO array antennas in limited space.

[0003] In the existing research on multi-port side-firing antenna units, patch antennas are generally used. In order to achieve high isolation and low correlation, there are polarization differences and certain pattern differences between different ports. Due to the side-firing requirements of the pattern, the polarizations of different ports cannot achieve 90 degrees of orthogonality, which makes the port isolation and correlation performance unable to meet the needs of practical applications. In addition, due to the limited number of side-firing orthogonal modes on patch antennas, the bandwidth of the antenna is generally narrow. Therefore, in order to achieve the miniaturization of high-performance large-scale MIMO array antennas, it is urgent to propose a method for implementing a side-firing multi-port antenna with high isolation and low correlation. Summary of the invention

[0004] In order to solve the problems of poor isolation, poor correlation and narrow bandwidth of non-orthogonal ports of multi-port MIMO antenna units in existing outdoor base stations, the present invention provides a co-frequency, co-polarization and co-aperture antenna with high isolation and low correlation.

[0005] A co-frequency, co-polarization, and co-aperture antenna with high isolation and low correlation comprises a reflective floor 3, a radiation patch 4, an odd-mode feeding network 5, a differential-mode feeding network 6, an odd-mode feeding coaxial line 7, and a differential-mode feeding coaxial line 8;

[0006] The first dielectric substrate 1 and the second dielectric substrate 2 are also included; the front side of the first dielectric substrate 1 and the back side of the second dielectric substrate 2 are bonded and vertically arranged on a reflective floor 3;

[0007] The radiation patch 4 and the odd-mode feeding network 5 are printed on the front and back of the first dielectric substrate 1 respectively, and the surface where the radiation patch 4 is located is parallel to the normal axis of the reflective floor 3; the differential-mode feeding network 6 is printed on the front of the second dielectric substrate 2; the odd-mode feeding coaxial line 7 is connected to the odd-mode feeding network 5, the differential-mode feeding coaxial line 8 is connected to the differential-mode feeding network 6, and the odd-mode feeding coaxial line 7 and the differential-mode feeding coaxial line 8 are both perpendicular to the first dielectric substrate 1;

[0008] A differential mode feeding hole 47 is provided at the center of the radiation patch 4; an upper odd mode feeding slot 41 and a lower odd mode feeding slot 42 are symmetrically provided on the radiation patch 4 with the differential mode feeding hole 47 as the center; a left differential mode feeding matching slot 45 and a right differential mode feeding matching slot 46 are symmetrically provided on the radiation patch 4 with the differential mode feeding hole 47 as the center; the opening of the left differential mode feeding matching slot 45 is connected to one end of the left differential mode feeding slot 43, and the other end of the left differential mode feeding slot 43 is connected to the two edges on the left side of the radiation patch 4; the opening of the right differential mode feeding matching slot 46 is connected to one end of the right differential mode feeding slot 44, and the other end of the right differential mode feeding slot 44 is connected to the two edges on the right side of the radiation patch 4; an odd mode feeding hole 48 is provided on the radiation patch 4 between the differential mode feeding hole 47 and the right differential mode feeding matching slot 46;

[0009] The odd-mode feeding network 5 is a U-shaped frame with an opening on one side in the horizontal direction, an upper side edge is an upper odd-mode coupling line 53, a lower side edge is a lower odd-mode coupling line 54, the outer side of the middle part is connected to the inner end of the input microstrip line 52, and an odd-mode probe hole 51 is opened on the outer end of the input microstrip line 52;

[0010] The differential mode feeding network 6 is a horizontal strip, and a differential mode probe hole 61 is provided in the center of the strip; a left differential mode power splitting line 62 and a right differential mode power splitting line 64 are symmetrically provided around the differential mode probe hole 61, and the outer end of the left differential mode power splitting line 62 is connected to a left differential mode matching branch 63, and the right differential mode power splitting line 64 is connected to a right differential mode matching branch 65;

[0011] The open end of the odd-mode feeding network 5 corresponds to one side of the left differential-mode matching branch 63 of the differential-mode feeding network 6 .

[0012] The odd-mode feeding coaxial line 7 connected to the odd-mode feeding network 5 forms a first working port, and the differential-mode feeding coaxial line 8 connected to the differential-mode feeding network 6 forms a second working port.

[0013] The radiation patterns of the two ports of the same-frequency, same-polarization and same-aperture antenna have side-ray characteristics and the polarization is the same.

[0014] The further technical solution is as follows:

[0015] The upper odd-mode feeding slot 41 and the lower odd-mode feeding slot 42 are located on the vertical center line of the radiation patch 4, and are symmetrically distributed up and down; the left differential-mode feeding slot 43 and the right differential-mode feeding slot 44 are located on the horizontal center line of the radiation patch 4, and are symmetrically distributed left and right; the left differential-mode feeding matching slot 45 and the right differential-mode feeding matching slot 46 are located on the horizontal center line of the radiation patch 4, and are symmetrically distributed left and right; the odd-mode feeding hole 48 is located on the horizontal connecting line of the center of the differential-mode feeding hole 47 and the right differential-mode feeding matching slot 46.

[0016] The upper odd-mode coupling line 53 and the lower odd-mode coupling line 54 have the same structural dimensions and are vertically symmetrical relative to the input microstrip line 52 .

[0017] The left differential mode power split line 62 and the right differential mode power split line 64 are symmetrical with the differential mode probe hole 61 as the center; the left differential mode matching branch node 63 and the right differential mode matching branch node 65 are both fan-shaped, with the fan surface of the left differential mode matching branch node 63 facing downward and the fan handle facing upward, and the fan surface of the right differential mode matching branch node 65 facing upward and the fan handle facing downward.

[0018] The overlapping operating frequencies of the two ports of the co-frequency, co-polarization and co-aperture antenna are 3.46-4.18 GHz or 5.46-6.18 GHz; the in-band reflection coefficient is less than -10 dB, the in-band peak gains are respectively greater than 6.3 dB and 6.87 dB, the in-band port isolations of the two ports are respectively greater than 21.27 dB and 18.56 dB, and the correlation coefficient is less than 0.002.

[0019] The beneficial technical effects of the present invention are embodied in the following aspects:

[0020] (1) Compared with the conventional side-firing unit antenna with orthogonal polarization ports, the radiation pattern of the two ports of the present invention also has side-firing characteristics, and the radiation of the two ports has the same polarization characteristic, which can also be used in outdoor large-scale MIMO array antennas.

[0021] (2) Compared with the existing three-port side-firing antenna that uses polarization difference to achieve high isolation, the present invention uses a differential feeding network and an odd-mode feeding network to respectively excite two groups of orthogonal modes, which makes it easy to achieve high isolation and low correlation between ports.

[0022] (3) The same-frequency, same-polarization, and same-aperture antenna of the present invention uses a back-to-back tapered slot structure etched on a dipole structure, so the impedance matching of the port can be easily adjusted by adjusting the matching slot and the matching fan-shaped branch. Since both the dipole and tapered slot structures are broadband structures, the present invention is more likely to achieve broadband characteristics.

[0023] (4) The main body of the same-frequency, same-polarization and same-aperture antenna of the present invention adopts a printed structure, in which the radiation patch and two sets of feeding networks are printed on two layers of substrates respectively. Compared with the traditional three-port antenna with a three-dimensional radiation structure, it has the advantages of planarization, low cost and short processing cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a front schematic diagram of the present invention.

[0025] Figure 2 It is a schematic diagram of the back side of the present invention.

[0026] Figure 3 It is a structural explosion diagram of the present invention.

[0027] Figure 4 It is a partial structural schematic diagram of the radiation patch of the present invention.

[0028] Figure 5 It is a schematic diagram of the odd-mode feeding structure of the present invention.

[0029] Figure 6 It is a schematic diagram of the differential mode feeding structure of the present invention.

[0030] Figure 7 This is a diagram of the S parameter simulation results of Example 1.

[0031] Figure 8 It is the two-dimensional radiation pattern of the far field when the odd-mode feeding port of Example 1 is excited.

[0032] Fig. 9 It is the two-dimensional radiation pattern of the far field when the differential feeding port of Example 1 is excited.

[0033] Fig.10 Graph showing the envelope correlation coefficient between the two ports of Example 1.

[0034] Fig.11 This is the S parameter simulation result diagram of Example 2.

[0035] Fig.12 It is the two-dimensional radiation pattern of the far field when the odd-mode feeding port of Example 2 is excited.

[0036] Fig.13 It is the two-dimensional radiation pattern of the far field when the differential feeding port of Example 2 is excited.

[0037] Fig.14 Graph showing the envelope correlation coefficient between the two ports of Example 2.

[0038] superior Figure 1-Figure 6Serial number: first dielectric substrate 1, second dielectric substrate 2, reflecting floor 3, radiating patch 4, odd-mode feeding network 5, differential-mode feeding network 6, odd-mode feeding coaxial line 7, differential-mode feeding coaxial line 8, upper odd-mode feeding slot 41, lower odd-mode feeding slot 42, left differential-mode feeding slot 43, right differential-mode feeding slot 44, left differential-mode feeding matching slot 45, right differential-mode feeding matching slot 46, differential-mode feeding hole 47, odd-mode feeding hole 48, odd-mode probe hole 51, input microstrip line 52, upper odd-mode coupling line 53, lower odd-mode coupling line 54, differential-mode probe hole 61, left differential-mode power splitter line 62, left differential-mode matching branch section 63, right differential-mode power splitter line 64, right differential-mode matching branch section 65. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] See also Figure 1 and Figure 2 A co-frequency, co-polarization, and co-aperture antenna with high isolation and low correlation includes a reflective floor 3, a radiation patch 4, an odd-mode feeding network 5, a differential-mode feeding network 6, an odd-mode feeding coaxial line 7, and a differential-mode feeding coaxial line 8; and also includes a first dielectric substrate 1 and a second dielectric substrate 2. The front surface of the first dielectric substrate 1 and the back surface of the second dielectric substrate 2 are attached and vertically installed on the reflective floor 3.

[0042] See also Figure 3 , Figure 1 and Figure 2 , the radiation patch 4 and the odd-mode feeding network 5 are printed on the front and back of the first dielectric substrate 1 respectively, and the surface where the radiation patch 4 is located is parallel to the normal axis of the reflective floor 3. The differential mode feeding network 6 is printed on the front of the second dielectric substrate 2; the odd-mode feeding coaxial line 7 is connected to the odd-mode feeding network 5; the differential mode feeding coaxial line 8 is connected to the differential mode feeding network 6, and the odd-mode feeding coaxial line 7 and the differential mode feeding coaxial line 8 are both perpendicular to the first dielectric substrate 1.

[0043] See also Figure 4, a differential mode feeding hole 47 is provided at the center of the radiation patch 4; the upper odd mode feeding slot 41 and the lower odd mode feeding slot 42 are symmetrically provided on the radiation patch 4 with the differential mode feeding hole 47 as the center, and the upper odd mode feeding slot 41 and the lower odd mode feeding slot 42 are located on the vertical center line of the radiation patch 4. The left differential mode feeding matching slot 45 and the right differential mode feeding matching slot 46 are symmetrically provided on the radiation patch 4 with the differential mode feeding hole 47 as the center. The opening of the left differential mode feeding matching slot 45 is connected to one end of the left differential mode feeding slot 43, and the other end of the left differential mode feeding slot 43 is connected to the two edges on the left side of the radiation patch 4; the opening of the right differential mode feeding matching slot 46 is connected to one end of the right differential mode feeding slot 44, and the other end of the right differential mode feeding slot 44 is connected to the two edges on the right side of the radiation patch 4; the left differential mode feeding slot 43 and the right differential mode feeding slot 44 are located on the horizontal center line of the radiation patch 4, and are symmetrically distributed on the left and right sides. An odd-mode feeding hole 48 is provided on the radiation patch 4 between the differential-mode feeding hole 47 and the right differential-mode feeding matching slot 46 . The odd-mode feeding hole 48 is located on a horizontal connecting line between the centers of the differential-mode feeding hole 47 and the right differential-mode feeding matching slot 46 .

[0044] See also Figure 5 The odd-mode feeding network 5 is a U-shaped frame with an opening on one side in the horizontal direction, an upper side is an upper odd-mode coupling line 53, a lower side is a lower odd-mode coupling line 54, the outer side of the middle part is connected to the inner end of the input microstrip line 52, and an odd-mode probe hole 51 is opened on the outer end of the input microstrip line 52. The upper odd-mode coupling line 53 and the lower odd-mode coupling line 54 have the same structure and size, and are symmetrical with respect to the input microstrip line 52.

[0045] See also Figure 6 The differential mode feeding network 6 is a horizontal strip, and a differential mode probe hole 61 is provided in the center of the strip; a left differential mode power split line 62 and a right differential mode power split line 64 are symmetrically provided with the differential mode probe hole 61 as the center, and the outer end of the left differential mode power split line 62 is connected to the left differential mode matching branch 63, and the right differential mode power split line 64 is connected to the right differential mode matching branch 65. The left differential mode matching branch 63 and the right differential mode matching branch 65 are both fan-shaped, and the fan surface of the left differential mode matching branch 63 is downward and the fan handle is upward, and the fan surface of the right differential mode matching branch 65 is upward and the fan handle is downward.

[0046] See also Figure 4 The open end of the odd-mode feeding network 5 corresponds to one side of the left differential-mode matching branch 63 of the differential-mode feeding network 6 .

[0047] See also Figure 1 and Figure 2 The odd-mode feeding coaxial line 7 connected to the odd-mode feeding network 5 forms a first working port, and the differential-mode feeding coaxial line 8 connected to the differential-mode feeding network 6 forms a second working port.

[0048] The specific operating parameters of the co-frequency, co-polarization and co-aperture antenna of Example 1 are described as follows:

[0049] The center frequency of the overlapping working frequency band of the first working port and the second working port is 3.75 GHz. The first dielectric substrate 1 and the second dielectric substrate 2 are both Rogers RO4350 substrates with a thickness of 0.508 mm, a floor size of 150 mm×150 mm, and an outer size of the radiation patch 4 of 40.8 mm×51.8 mm.

[0050] The upper odd-mode feeding slot 41 and the lower odd-mode feeding slot 42 have the same size, with a length of 18.8 mm and a width of 1.2 mm. The upper odd-mode coupling line 53 and the lower odd-mode coupling line 54 have the same size, with a length of 33.7 mm and a width of 0.24 mm. The input microstrip line 52 is a printed microstrip line with a width of 1 mm and a length of 4.26 mm. The left differential-mode power splitter line 62 and the right differential-mode power splitter line 64 have the same size, with a width of 1 mm and a total length of 25.2 mm. The left differential-mode matching branch section 63 and the right differential-mode matching branch section 65 are both fan-shaped with a fan angle of 90 degrees and a radius of 5 mm. The left differential-mode feeding matching slot 45 and the right differential-mode feeding matching slot 46 are both circular slots with a radius of 2.5 mm, and the center spacing between the two circular slots is 25 mm. The left differential-mode feeding slot 43 and the right differential-mode feeding slot 44 have the same size, with a length of 10.9 mm and an end slot width of 11.4 mm. The height between the center of the radiation patch 4 and the reflective floor 3 is 45.5 mm.

[0051] The simulation results show that the overlapping operating frequency range of the two ports is 3.46~4.18GHz, the in-band reflection coefficient is less than -10dB, the peak gains of the two ports in the band are greater than 6.3dB, the in-band port isolation is greater than 21.27dB, and the correlation coefficient is less than 0.002.

[0052] The working principle of the present invention is described in detail as follows:

[0053] The radiation patch 4 printed on the front of the first dielectric substrate 1 is itself a dipole structure of half wavelength. The dipole mode on the dipole structure can be excited by the odd-mode feeding network 5 through the upper odd-mode coupling line 53 and the lower odd-mode coupling line 54, thereby realizing omnidirectional radiation in the vertical direction. According to the mirror principle, the electromagnetic waves radiated by the dipole eventually radiate in the upper half space due to the effect of the reflection floor 3. Through the characteristic mode theory analysis, it can be known that after the left differential mode feeding slot 43 and the right differential mode feeding slot 44 are introduced to the radiation patch 4, the original dipole structure generates another set of modes showing omnidirectional characteristics in the vertical direction, and this set of modes is orthogonal to the original dipole mode, and this set of modes can be excited by the differential mode feeding network 6. Due to the effect of the reflection floor 3, the radiation direction is also changed from the original omnidirectional to the upper half space side emission. By optimizing the sizes of the upper odd-mode coupling line 53, the lower odd-mode coupling line 54, the upper odd-mode feeding slot 41 and the lower odd-mode feeding slot 42, the impedance matching of the dipole mode port can be achieved. By optimizing the sizes of the left differential-mode feeding slot 43, the right differential-mode feeding slot 44, the left differential-mode feeding matching slot 45, the right differential-mode feeding matching slot 46, the left differential-mode matching branch section 63, the right differential-mode matching branch section 65, the left differential-mode power splitting line 62 and the right differential-mode power splitting line 64, the impedance of the second working port can be better matched. Since the two working ports excite their two groups of orthogonal modes respectively, the ports theoretically have higher isolation and lower correlation.

[0054] See also Figure 7 , gives the return loss of the port S parameters of the antenna in this embodiment 1 and the isolation between the two ports. From the simulation results, it can be seen that the two ports of the antenna in this embodiment have overlapping operating frequencies, and the isolation is greater than 21.27dB in the overlapping operating frequency band.

[0055] See also Figure 8 , where the curves with triangles and five-star symbols are the main polarization radiation patterns of the E-plane and the H-plane, and the other two lines are the cross-polarization far-field patterns. From the main polarization radiation pattern, it can be seen that in this embodiment 1, when the antenna works in the odd mode, the maximum radiation direction is in the upper half space, the front-to-back ratio is nearly 20dB, and it has a good side-firing far-field pattern.

[0056] See also Fig. 9 , where the curves with triangles and five-star symbols are the main polarization radiation patterns of the E-plane and the H-plane, and the other two lines are the cross-polarization far-field patterns. It can be seen from the main polarization radiation pattern that when the differential feed port of the antenna in this embodiment 1 is excited, the maximum radiation direction is in the upper half space, the front-to-back ratio is greater than 15dB, and it also has a side-emitting far-field pattern.

[0057] See also Fig.10In this embodiment 1, the correlation coefficient between the two ports of the antenna is less than 0.002 within the overlapping working frequency band.

[0058] Example 2

[0059] The same frequency, same polarization and same aperture antenna structure of the second embodiment is the same as that of the first embodiment, and the specific working parameters are described as follows:

[0060] The center frequency of the overlapping working frequency band of the first working port and the second working port is 5.82 GHz.

[0061] The first dielectric substrate 1 and the second dielectric substrate 2 are both Rogers RO4350 substrates with a thickness of 0.508 mm, the floor size is 150 mm×150 mm, and the outer size of the radiation patch 4 is 18 mm×21.8 mm.

[0062] The upper odd-mode feeding slot 41 and the lower odd-mode feeding slot 42 have the same size, with a length of 8.1 mm and a width of 1 mm. The upper odd-mode coupling line 53 and the lower odd-mode coupling line 54 have the same size, with a length of 6 mm and a width of 0.24 mm. The input microstrip line 52 is a printed microstrip line with a width of 1 mm and a length of 2.76 mm. The left differential-mode power splitter line 62 and the right differential-mode power splitter line 64 have the same size, with a width of 1 mm and a total length of 25.2 mm. The left differential-mode matching branch section 63 and the right differential-mode matching branch section 65 are both sectors with a sector angle of 90 degrees and a radius of 4 mm. The left differential-mode feeding matching slot 45 and the right differential-mode feeding matching slot 46 are both circular slots with a radius of 1.4 mm, and the center spacing between the two circular slots is 12.2 mm. The left differential-mode feeding slot 43 and the right differential-mode feeding slot 44 have the same size, with a length of 3.4 mm and a terminal slot width of 2.7 mm. The height between the center of the radiation patch 4 and the reflective floor 3 is 11.5 mm.

[0063] The simulation results show that the overlapping operating frequency range of the two ports is 5.46~6.18GHz, the in-band reflection coefficient is less than -10dB, the peak gains of the two ports in the band are greater than 6.87dB, the in-band port isolation is greater than 18.56dB, and the correlation coefficient is less than 0.002.

[0064] See also Fig.11 It can be seen from the HFSS simulation results that the two ports of the antenna in this embodiment 2 have overlapping operating frequencies, and the isolation within the overlapping operating frequency band is greater than 18.56 dB.

[0065] See also Fig.12, where the curves with triangles and five-star symbols are the main polarization radiation patterns of the E-plane and the H-plane, and the other two lines are the cross-polarization far-field patterns. It can be seen from the main polarization radiation pattern that the maximum radiation direction of the antenna in this embodiment 2 when working in the odd mode state is in the upper half space, and the front and rear are greater than 30dB, which has a good side-firing far-field pattern.

[0066] See also Fig.13 , where the curves with triangles and five-star symbols are the main polarization radiation patterns of the E-plane and the H-plane, and the other two lines are the cross-polarization far-field patterns. It can be seen from the main polarization radiation pattern that when the differential feeding port of the antenna in this embodiment 2 is excited, the front-to-back ratio of the pattern is greater than 12dB, which can cover the upper half of the space and also has a side-emitting far-field pattern.

[0067] See also Fig.14 , the correlation coefficient between the two ports of the antenna in this embodiment 2 is less than 0.002 within the overlapping working frequency band.

[0068] It will be easily understood by those skilled in the art that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A co-frequency, co-polarization, and co-aperture antenna with high isolation and low correlation, comprising a reflective floor (3), a radiation patch (4), an odd-mode feeding network (5), a differential-mode feeding network (6), an odd-mode feeding coaxial line (7), and a differential-mode feeding coaxial line (8); characterized in that: It also comprises a first dielectric substrate (1) and a second dielectric substrate (2); the front surface of the first dielectric substrate (1) and the back surface of the second dielectric substrate (2) are bonded and vertically arranged on a reflective floor (3); The radiation patch (4) and the odd-mode feeding network (5) are printed on the front and back sides of the first dielectric substrate (1), respectively, and the surface on which the radiation patch (4) is located is parallel to the normal axis of the reflective floor (3); the differential-mode feeding network (6) is printed on the front side of the second dielectric substrate (2); the odd-mode feeding coaxial line (7) is connected to the odd-mode feeding network (5), the differential-mode feeding coaxial line (8) is connected to the differential-mode feeding network (6), and both the odd-mode feeding coaxial line (7) and the differential-mode feeding coaxial line (8) are perpendicular to the first dielectric substrate (1); A differential mode feeding hole (47) is provided at the center of the radiation patch (4); an upper odd mode feeding slot (41) and a lower odd mode feeding slot (42) are symmetrically provided on the radiation patch (4) with the differential mode feeding hole (47) as the center; a left differential mode feeding matching slot (45) and a right differential mode feeding matching slot (46) are symmetrically provided on the radiation patch (4) with the differential mode feeding hole (47) as the center; the opening of the left differential mode feeding matching slot (45) is connected to the left differential mode feeding matching slot (46). One end of the slot (43), and the other end of the left differential mode feeding slot (43) are connected to the two edges of the left side of the radiation patch (4); the opening of the right differential mode feeding matching slot (46) is connected to one end of the right differential mode feeding slot (44), and the other end of the right differential mode feeding slot (44) is connected to the two edges of the right side of the radiation patch (4); an odd mode feeding hole (48) is opened on the radiation patch (4) between the differential mode feeding hole (47) and the right differential mode feeding matching slot (46); The odd-mode feeding network (5) is a U-shaped frame with an opening on one side in the horizontal direction, an upper side edge is an upper odd-mode coupling line (53), a lower side edge is a lower odd-mode coupling line (54), the outer side of the middle portion is connected to the inner end of the input microstrip line (52), and an odd-mode probe hole (51) is provided on the outer end of the input microstrip line (52); The differential mode feeding network (6) is in the form of a horizontal strip, with a differential mode probe hole (61) provided at the center of the strip; a left differential mode power splitting line (62) and a right differential mode power splitting line (64) are symmetrically provided around the differential mode probe hole (61), the outer end of the left differential mode power splitting line (62) being connected to a left differential mode matching branch node (63), and the right differential mode power splitting line (64) being connected to a right differential mode matching branch node (65); The open end of the odd-mode feeding network (5) corresponds to one side of the left differential-mode matching branch (63) of the differential-mode feeding network (6); An odd-mode feeding coaxial line (7) connected to the odd-mode feeding network (5) forms a first working port, and a differential-mode feeding coaxial line (8) connected to the differential-mode feeding network (6) forms a second working port; The radiation patterns of the two ports of the same-frequency, same-polarization and same-aperture antenna have side-ray characteristics and the polarization is the same.

2. The same-frequency, same-polarization, and same-aperture antenna with high isolation and low correlation according to claim 1, characterized in that: The upper odd-mode feeding slot (41) and the lower odd-mode feeding slot (42) are located on the vertical center line of the radiation patch (4) and are symmetrically distributed in the upper and lower parts; the left differential-mode feeding slot (43) and the right differential-mode feeding slot (44) are located on the horizontal center line of the radiation patch (4) and are symmetrically distributed in the left and right parts; the left differential-mode feeding matching slot (45) and the right differential-mode feeding matching slot (46) are located on the horizontal center line of the radiation patch (4) and are symmetrically distributed in the left and right parts; and the odd-mode feeding hole (48) is located on the horizontal connecting line of the centers of the differential-mode feeding hole (47) and the right differential-mode feeding matching slot (46).

3. The same-frequency, same-polarization, and same-aperture antenna with high isolation and low correlation according to claim 1, characterized in that: The upper odd-mode coupling line (53) and the lower odd-mode coupling line (54) have the same structural dimensions and are symmetrical up and down relative to the input microstrip line (52).

4. The same-frequency, same-polarization, and same-aperture antenna with high isolation and low correlation according to claim 1, characterized in that: The left differential mode power splitting line (62) and the right differential mode power splitting line (64) are symmetrical with respect to the differential mode probe hole (61) as the center; the left differential mode matching branch node (63) and the right differential mode matching branch node (65) are both fan-shaped, with the fan surface of the left differential mode matching branch node (63) facing downward and the fan handle facing upward, and the fan surface of the right differential mode matching branch node (65) facing upward and the fan handle facing downward.

5. The same-frequency, same-polarization, and same-aperture antenna with high isolation and low correlation according to claim 1, characterized in that: The overlapping operating frequencies of the two ports of the co-frequency, co-polarization and co-aperture antenna are 3.46-4.18 GHz or 5.46-6.18 GHz; the in-band reflection coefficient is less than -10 dB, the in-band peak gains are respectively greater than 6.3 dB and 6.87 dB, the in-band port isolations of the two ports are respectively greater than 21.27 dB and 18.56 dB, and the correlation coefficient is less than 0.002.

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