Electromagnetic transparent dual-polarization base station antenna

Abstract

The invention relates to an electromagnetic transparent dual-polarization base station antenna. The invention relates to the technical field of mobile communication. The antenna comprises a first radiator, a second radiator, a third radiator, a fourth radiator, a dielectric substrate, a first balun feed structure, a second balun feed structure and a common metal ground layer. Compared with the prior art, the antenna has the advantages that the radiating body is provided with various types of grooves, so that the electromagnetic transparent frequency band can cover the two 5G frequency bands of 3.3-3.8 GHz and 4.8-5 GHz, and meanwhile, the antenna can work in the frequency band of 1.7-2.7 GHz. Under the condition of radiation of the lower high-frequency antenna, the slots on the radiator generate offset currents in opposite directions, and secondary radiation generated by the currents is offset mutually, so that the radiation of the lower high-frequency antenna cannot be shielded.

Description

Technical Field

[0001] The invention relates to the technical field of mobile communications and is an electromagnetically transparent dual-polarization base station antenna. Background Art

[0002] As the requirements for communication capacity, speed, and latency continue to increase, and communication technology continues to iterate, the number of antennas in base station antennas is also increasing, and the array size is getting larger and larger. The frequency bands allocated by the iteration of communication technology have increased, which has reduced the coverage of the corresponding base station antennas. To achieve the coverage of the previous generation, the density of base stations needs to be increased. This has greatly increased the demand for the construction of various encrypted base stations and indoor base stations.

[0003] On the other hand, the change of communication standards cannot be achieved overnight, and base stations should meet the needs of users using different communication standards. Therefore, the 5G communication system needs to be compatible with the previous 2G / 3G / 4G communication systems. Due to the limited space resources on the base station, the 2G / 3G / 4G antennas have been deployed at the best position of the base station radiation aperture, and antennas of different frequency bands are often chosen to share the aperture to improve the base station.

[0004] When traditional base station antennas are densely deployed, there is serious mutual coupling between arrays. There is also cross-band mutual coupling between antennas in different frequency bands, and the radiation shielding of the high-frequency antenna below by the low-frequency antenna above. These problems cause the radiation performance of the antenna to decline or even worsen compared to its performance when it radiates alone.

[0005] Therefore, developing a new base station antenna unit structure to achieve electromagnetic transparency of the antenna unit to antenna units in other frequency bands that are blocked by its radiation is an effective way to alleviate the shortage of base station site space resources without sacrificing performance, improve the overall network efficiency and user experience, and promote the development of mobile communications. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides an electromagnetically transparent dual-polarized base station antenna. The feeding structure of the coaxial feeder of the present invention avoids the use of any wire bridge, short-circuit pin or feeding probe, so that the feeding structure of the dual-polarized antenna is simple and the manufacturing cost is reduced.

[0007] The present invention provides the following technical solutions:

[0008] An electromagnetically transparent dual-polarized base station antenna, the antenna comprising: a first radiator, a second radiator, a third radiator, a fourth radiator, a dielectric substrate, a first balun feeding structure, a second balun feeding structure and a common metal stratum;

[0009] The first balun feeding structure and the second balun feeding structure are printed on the front of the dielectric substrate. The first balun feeding structure is arranged behind the first radiator and the third radiator and connected thereto. The second balun feeding structure is arranged behind the second radiator and the fourth radiator and connected thereto. The two feeding baluns are vertically embedded and embedded in a common metal stratum. A coaxial line is used under the common metal stratum to feed the balun feeding structure.

[0010] The common metal ground layer is used to reflect the downward radiation energy of the first radiator, the second radiator, the third radiator and the fourth radiator and is connected to the reverse back plates of the first balun feeding structure and the second balun feeding structure as a ground.

[0011] Preferably, the radiator is obtained by chamfering a circular patch and opening a series of grooves, wherein the groove shapes include: a rectangular long groove, a clamp-shaped groove and a fan-shaped thin groove.

[0012] Preferably, the rectangular slot is located at the radial line of the circular radiator, and the direction angle is consistent with the ±45° dual polarization direction of the antenna;

[0013] The clamp-type slot is attached to the radial line and the outer circumference of the circular radiator. There are two clamp-type slots in the quarter-circle unit of the antenna radiator. One side of the clamp-type slot is attached to the rectangular long slot, and the other side is attached to one side of another clamp-type slot. The two clamp-type slots form a quarter-sector.

[0014] The fan-shaped fine groove is a groove opened on the inner patch surrounded by the clamp-shaped groove in a fan shape, close to the clamp-shaped groove.

[0015] Preferably, the polarizations of the radiator in two directions are fed by two balun feeding structures respectively; the two balun feeding structures are printed on two dielectric substrates respectively, the other side of the dielectric substrate is a common metal layer, the middle is separated by air due to the embedding, the two dielectric substrates are perpendicular to each other and are placed perpendicular to the common metal layer; one dielectric substrate has a groove in the lower part, and the other dielectric substrate has a groove in the upper part, and the two can be embedded and placed perpendicular to each other.

[0016] Preferably, the balun feeding structure is in a "Γ" shape, and the adjacent structures of the two balun feeding structures are connected in a semicircular ring to reduce mutual interference between the adjacent baluns.

[0017] The balun feeding structure adds a branch on the basis of the overall "Γ" shape, and the polarizations of the radiator in two directions are fed by two coaxial cables respectively; a pair of dipole units responsible for radiation in one polarization direction are printed on the upper and lower surfaces of the dielectric substrate respectively.

[0018] Preferably, in one polarization direction, the outer conductor of the coaxial line is connected to one of a pair of dipoles located on the lower surface of the dielectric substrate, and the other of the pair of dipoles located on the upper surface of the dielectric substrate extends the microstrip stub to the position of the coaxial line, and the inner conductor is connected thereto;

[0019] In another polarization direction, one of the pair of dipoles located on the lower surface of the dielectric substrate extends the microstrip stub to below the other of the pair of dipoles located on the upper surface of the dielectric substrate, the inner conductor of the coaxial line is connected to the dipole on the lower surface of the dielectric substrate, and the outer conductor is connected to the dipole on the upper surface of the dielectric substrate.

[0020] Preferably, the inner conductor is connected to the lower radiator of the dielectric substrate, and the extension length of the short stub does not completely cover the coaxial line. The remaining part of the outer conductor can bypass the short stub and connect to the upper radiator of the dielectric substrate. In the sector-shaped dipole unit, the inner corners are chamfered.

[0021] A base station antenna comprises an electromagnetically transparent dual-polarized base station antenna and a reflector. The reflector is arranged behind the magnetically transparent dual-polarized base station antenna and is used for directional radiation thereof.

[0022] A three-band base station antenna, the antenna comprising an electromagnetically transparent dual-polarized base station antenna, another dual-band antenna coaxially placed below the electromagnetically transparent antenna, the working frequency band of the overall antenna structure can cover three frequency bands: 1.7-2.7GHz, 3.3-3.8GHz and 4.8-5GHz, each frequency band can radiate normally, and interference between frequency bands is extremely small.

[0023] A method for designing an electromagnetically transparent dual-polarized base station antenna is characterized in that the method is implemented based on a magnetically transparent dual-polarized base station antenna.

[0024] The present invention has the following beneficial effects:

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] Compared with the prior art, the present invention can achieve electromagnetic transparent frequency bands covering the two 5G frequency bands of 3.3-3.8GHz and 4.8-5GHz by opening various types of slots on the radiator, while the antenna itself can operate in the 1.7-2.7GHz frequency band. Under the condition of radiation from the high-frequency antenna below, the slots on the radiator generate cancellation currents in opposite directions, and the secondary radiation generated by the currents can cancel each other out, so there is no shielding effect on the radiation of the high-frequency antenna below.

[0027] In terms of the feeding structure, the balun feeding structure is stable and firm, and does not require additional nylon columns or other fixing methods. Balun feeding can provide multiple resonance points within the band, making the matching coefficient within the band stable. At the same time, the additional filter branch design can reduce interference with high-frequency antennas and eliminate the space occupied by additional filters on the base station.

[0028] The feeding structure of the coaxial feed line avoids using any wire bridge, short-circuit pin or feeding probe, so that the feeding structure of the dual-polarization antenna is simple and the manufacturing cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 Shown is a schematic diagram of the structure of an electromagnetically transparent dual-polarized base station antenna unit of the present invention;

[0031] Figure 2 Shown is a top view structural diagram of the electromagnetically transparent dual-polarized base station antenna radiator of the present invention;

[0032] Figure 3 Shown is a side view structural diagram of the electromagnetically transparent dual-polarized base station antenna radiator of the present invention;

[0033] Figure 4 Shown is a schematic diagram of the structure of the electromagnetically transparent dual-polarized coaxial tri-band base station antenna of the present invention;

[0034] Figure 5 Shown is a schematic diagram of the structure of the electromagnetically transparent dual-polarized base station antenna unit and the high-frequency antenna array of the present invention;

[0035] Figure 6 Shown are the S parameters of the balun-fed electromagnetically transparent dual-polarized base station antenna unit port of the present invention;

[0036] Figure 7 Shown are the S parameters of the coaxial-fed electromagnetically transparent dual-polarization base station antenna port of the present invention;

[0037] Figure 8 Shown is the actual gain of the balun-fed electromagnetically transparent dual-polarization base station antenna of the present invention;

[0038] Fig. 9 Shown is a gain comparison of the electromagnetically transparent dual-polarization coaxial tri-band base station antenna of the present invention. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] The present invention is described in detail below in conjunction with specific embodiments. Specific embodiment one:

[0045] In view of the shortcomings of the prior art, the present invention provides an electromagnetically transparent dual-polarized base station antenna:

[0046] according to Figures 1 to 9 As shown:

[0047] An electromagnetically transparent dual-polarized base station antenna, the antenna comprising: a first radiator 1, a second radiator 2, a third radiator 3, a fourth radiator 4, a dielectric substrate 5, a first balun feeding structure 6, a second balun feeding structure 7 and a common metal layer 8;

[0048] The first balun feeding structure 6 and the second balun feeding structure 7 are printed on the front of the dielectric substrate 5. The first balun feeding structure 6 is arranged behind the first radiator 1 and the third radiator 3 to be connected thereto, and the second balun feeding structure 7 is arranged behind the second radiator 2 and the fourth radiator 4 to be connected thereto. The two feeding baluns are vertically embedded and embedded in a common metal stratum 8, and a coaxial line is used under the common metal stratum 8 to feed the balun feeding structure.

[0049] The common metal ground layer 8 is used to reflect the downward radiation energy of the first radiator 1, the second radiator 2, the third radiator 3, and the fourth radiator 4, and is connected to the reverse backplanes of the first balun feeding structure 6 and the second balun feeding structure 7 as a ground.

[0050] The present invention can achieve electromagnetic transparent frequency bands covering the two 5G frequency bands of 3.3-3.8GHz and 4.8-5GHz by opening various types of slots on the radiator, while the antenna itself can operate in the 1.7-2.7GHz frequency band. Under the condition of radiation from the high-frequency antenna below, the slots on the radiator generate cancellation currents in opposite directions, and the secondary radiation generated by the currents can cancel each other out, so there is no shielding effect on the radiation of the high-frequency antenna below.

[0051] In terms of the feeding structure of the present invention, the balun feeding structure is stable and firm, and does not require additional fixing methods such as nylon columns. The balun feeding can provide multiple resonance points within the band, so that the matching coefficient within the band is stable. At the same time, the additional filter branch design can reduce the interference to the high-frequency antenna and eliminate the space occupation of the additional filter on the base station.

[0052] The feeding structure of the coaxial feed line of the present invention avoids using any wire bridge, short-circuit pin or feeding probe, so that the feeding structure of the dual-polarization antenna is simple and the manufacturing cost is reduced. Specific embodiment 2:

[0054] The difference between the second embodiment of the present application and the first embodiment is that:

[0055] The radiator is obtained by chamfering a circular patch and opening a series of grooves, wherein the groove shapes include: a rectangular long groove, a clamp-shaped groove and a fan-shaped thin groove. Specific embodiment three:

[0057] The difference between the third embodiment of the present application and the second embodiment is that:

[0058] The rectangular slot is located at the radial line of the circular radiator, and its direction angle is consistent with the ±45° dual polarization direction of the antenna;

[0059] The clamp-type slot is attached to the radial line and the outer circumference of the circular radiator. There are two clamp-type slots in the quarter-circle unit of the antenna radiator. One side of the clamp-type slot is attached to the rectangular long slot, and the other side is attached to one side of another clamp-type slot. The two clamp-type slots form a quarter-sector.

[0060] The fan-shaped fine groove is a groove opened on the inner patch surrounded by the clamp-shaped groove in a fan shape, close to the clamp-shaped groove. Specific embodiment four:

[0062] The difference between the fourth embodiment of the present application and the third embodiment is that:

[0063] The polarizations of the radiator in two directions are fed by two balun feeding structures respectively; the two balun feeding structures are printed on two dielectric substrates respectively, the other side of the dielectric substrate is a common metal layer, the middle is separated by air due to the embedding, the two dielectric substrates are perpendicular to each other and are placed perpendicular to the common metal layer; a dielectric substrate has a groove in the lower part, and the other dielectric substrate has a groove in the upper part, and the two can be embedded and placed perpendicular to each other. Specific embodiment five:

[0065] The difference between the fifth embodiment of the present invention and the fourth embodiment is that:

[0066] The balun feeding structure is in a "Γ" shape, and the two balun feeding structures are connected in a semicircular ring at adjacent locations to reduce mutual interference between the adjacent baluns.

[0067] The balun feeding structure adds a branch on the basis of the overall "Γ" shape, and the polarizations of the radiator in two directions are fed by two coaxial cables respectively; a pair of dipole units responsible for radiation in one polarization direction are printed on the upper and lower surfaces of the dielectric substrate respectively. Specific embodiment six:

[0069] The difference between the sixth embodiment of the present invention and the fifth embodiment is that:

[0070] In one polarization direction, the outer conductor of the coaxial line is connected to one of a pair of dipoles located on the lower surface of the dielectric substrate, and the other of the pair of dipoles located on the upper surface of the dielectric substrate extends the microstrip stub to the position of the coaxial line, and the inner conductor is connected to it;

[0071] In another polarization direction, one of the pair of dipoles located on the lower surface of the dielectric substrate extends the microstrip stub to below the other of the pair of dipoles located on the upper surface of the dielectric substrate, the inner conductor of the coaxial line is connected to the dipole on the lower surface of the dielectric substrate, and the outer conductor is connected to the dipole on the upper surface of the dielectric substrate. Specific embodiment seven:

[0073] The difference between the seventh embodiment of the present invention and the sixth embodiment is that:

[0074] The inner conductor is connected to the lower radiator of the dielectric substrate. The extension length of the short stub does not completely cover the coaxial line. The remaining part of the outer conductor is able to bypass the short stub and connect to the upper radiator of the dielectric substrate. In the fan-shaped dipole unit, the inner corners are chamfered. Specific embodiment eight:

[0076] The difference between the eighth embodiment of the present invention and the seventh embodiment is that:

[0077] The invention provides a base station antenna, which comprises an electromagnetically transparent dual-polarization base station antenna and a reflecting plate. The reflecting plate is arranged behind the magnetically transparent dual-polarization base station antenna and is used for directional radiation thereof. Specific embodiment nine:

[0079] The difference between the ninth embodiment of the present invention and the eighth embodiment is that:

[0080] The present invention provides a three-band base station antenna, which includes an electromagnetically transparent dual-polarized base station antenna, and another dual-band antenna is coaxially placed below the electromagnetically transparent antenna. The working frequency band of the overall antenna structure can cover three frequency bands: 1.7-2.7GHz, 3.3-3.8GHz and 4.8-5GHz. Each frequency band can radiate normally, and the interference between frequency bands is extremely small. Specific embodiment ten:

[0082] The difference between the tenth embodiment of the present invention and the ninth embodiment is that:

[0083] The invention provides an electromagnetically transparent dual-polarized base station antenna design method, which is characterized in that the method is implemented based on a magnetically transparent dual-polarized base station antenna.

[0084] The present invention can achieve electromagnetic transparent frequency bands covering the two 5G frequency bands of 3.3-3.8GHz and 4.8-5GHz by opening various types of slots on the radiator, while the antenna itself can operate in the 1.7-2.7GHz frequency band. Under the condition of radiation from the high-frequency antenna below, the slots on the radiator generate cancellation currents in opposite directions, and the secondary radiation generated by the currents can cancel each other out, so there is no shielding effect on the radiation of the high-frequency antenna below.

[0085] In terms of the feeding structure of the present invention, the balun feeding structure is stable and firm, and does not require additional fixing methods such as nylon columns. The balun feeding can provide multiple resonance points within the band, so that the matching coefficient within the band is stable. At the same time, the additional filter branch design can reduce the interference to the high-frequency antenna and eliminate the space occupation of the additional filter on the base station.

[0086] The feeding structure of the coaxial feed line of the present invention avoids using any wire bridge, short-circuit pin or feeding probe, so that the feeding structure of the dual-polarization antenna is simple and the manufacturing cost is reduced. Specific embodiment eleven:

[0088] The difference between the eleventh embodiment of the present invention and the tenth embodiment is that:

[0089] See also Figure 1The core of the present invention is to provide an electromagnetically transparent dual-polarized base station antenna unit, including a first radiator 1, a second radiator 2, a third radiator 3, a fourth radiator 4, a dielectric substrate 5, a first balun feeding structure 6, a second balun feeding structure 7 and a common metal layer 8;

[0090] The first balun feeding structure 6 is arranged behind the first radiator 1 and the third radiator 3 and connected thereto, and the second balun feeding structure 7 is arranged behind the second radiator 2 and the fourth radiator 4 and connected thereto. The two feeding baluns are vertically embedded and embedded in a common metal layer 8, and a coaxial line is used to feed the baluns under the common metal layer 8. The common metal layer 8 is used to reflect the downward radiation energy of the radiator and is connected to the reverse backplane of the first balun feeding structure 6 and the second balun feeding structure 7 as a ground.

[0091] The specific structure and parameters of the radiator are as follows: Figure 2 The radiator is obtained by cutting various types of slots on the basis of the fan-shaped patch, including: a clamp-shaped slot 9 attached to the edge of the fan-shaped patch, a rectangular long slot 10 of a radial line, and a fan-shaped long slot 11 placed inside and attached to the clamp-shaped slot.

[0092] The main parameters of the radiator are as follows: dipole radius R1 = 30 mm, dipole patch spacing W0 = 0.6 mm, rectangular long slot width W1 = 0.5 mm, one side slot width of the clamp-type slot W2 = 4.5 mm, the middle slot width of the clamp-type slot W3 = 0.7 mm, and the other side slot width of the clamp-type slot W4 = 1.2 mm.

[0093] Figure 3 The specific structure of two balun feeds is shown. The balun feed structure is printed on the front of the dielectric substrate, and the metal backplane is printed on the back. There is a slot in the middle of the dielectric substrate, which can be interlocked. There is also a rectangular protrusion on the top to fix the radiator on it. The middle intersection of the balun feed structure is arc-processed, and the filter branch is extended on the main feed arm. The bottom is fed through a coaxial line. The metal backplane is connected to the common metal layer 8. Specific embodiment twelve:

[0095] The difference between the twelfth embodiment of the present invention and the eleventh embodiment is that:

[0096] Figure 4An electromagnetically transparent dual-polarized coaxial tri-band base station antenna structure is demonstrated. The antenna is based on the aforementioned electromagnetically transparent dual-polarized base station antenna unit, and a coaxial high-frequency antenna is placed at the bottom. The two layers of dielectric substrates of the high-frequency antenna are coaxial feeders for differential feeding of the high-frequency antenna, radiators on the upper surface of the dielectric substrate, radiators on the upper surface of the dielectric substrate, and radiators on the lower surface of the dielectric substrate. The main function of the radiator is to expand the bandwidth. The high-frequency antenna has a wide radiation bandwidth and can cover the two 5G frequency bands of 3.3-3.8GHz and 4.8-5GHz. The electromagnetically transparent dual-polarized coaxial tri-band base station antenna can cover three typical communication frequency bands of 1.7-2.7GHz, 3.3-3.8GHz and 4.8-5GHz. Since the uppermost electromagnetically transparent radiator is electromagnetically transparent to the 3.3-3.8GHz and 4.8-5GHz frequency bands, the lower high-frequency antenna can radiate normally in these two frequency bands without being blocked. The electromagnetically transparent dual-polarized coaxial tri-band base station antenna will greatly improve the space utilization of the base station.

[0097] Example 3

[0098] Figure 5 The periodic unit array composed of electromagnetically transparent dual-polarized base station antennas and high-frequency antennas is displayed. It consists of 1 electromagnetically transparent dual-polarized base station antenna and 4 high-frequency base station antennas. The periodic unit can be extended periodically in the x or y direction to form a larger base station antenna array. It is equivalent to inserting electromagnetically transparent dual-polarized base station antennas at intervals in the high-frequency antenna array, and both antennas can work normally in their respective frequency bands. Compared with the traditional base station form of arranging antenna arrays of different frequency bands in groups in the horizontal direction, this array arrangement saves more base station space.

[0099] Figure 6 The S parameter simulation results of the feeding port of the electromagnetically transparent dual-polarized base station antenna fed by the balun, where S11 and S22 are the reflection coefficients of the port. In the figure, the reflection coefficient is lower than -15dB in the 1.7-2.7GHz frequency band, indicating that the antenna has excellent matching in this frequency band. S12 and S21 are the isolation coefficients between the two polarized feeding ports. In the figure, the isolation coefficients are all below -30dB in the 1.7-2.7GHz frequency band, indicating that the isolation between the two polarized feeding ports of the antenna is excellent.

[0100] Figure 7 The S parameter simulation results of the feeding port of the electromagnetically transparent dual-polarized base station antenna with coaxial feeding, where S11 and S22 are the reflection coefficients of the port. In the figure, the reflection coefficient is lower than -10dB in the 1.7-2.7GHz frequency band, indicating that the antenna has excellent matching in this frequency band. S12 and S21 are the isolation coefficients between the two polarized feeding ports. In the figure, the isolation coefficient is basically around -30dB in the 1.7-2.7GHz frequency band, indicating that the isolation between the two polarized feeding ports of the antenna is excellent.

[0101] Figure 8 The actual gain simulation results of the electromagnetically transparent dual-polarized base station antenna fed by the balun. As can be seen from the figure, the actual gain of the antenna is stable in the working frequency band of 1.7-2.7GHz, basically at 8dBi. Due to the addition of filtering intervals in the balun structure, it can be observed that after 3GHz, the actual gain of the antenna drops sharply to below 0dBi, reducing the radiation interference of the antenna to the high-frequency antenna on the base station.

[0102] Fig. 9 This is a comparison of the actual gain of the high-frequency antenna alone and the electromagnetically transparent dual-polarized base station antenna above it in the 3.3-3.8GHz and 4.8-5GHz frequency bands. As can be seen from the figure, after the high-frequency antenna radiates through the electromagnetically transparent dual-polarized base station antenna, except for the actual gain in the 4.0-4.7GHz frequency band, which decreases due to shielding, the actual gain in the 3.3-4.0GHz frequency band is consistent with the actual gain when the high-frequency antenna exists alone on average, and some have increased. In the 4.8-5GHz frequency band, the actual gain is only slightly lower than the actual gain when the high-frequency antenna exists alone. Overall, the actual gain in the 3.3-3.8GHz and 4.8-5GHz frequency bands is higher than 8.5dB. This shows that the electromagnetically transparent antenna does achieve the electromagnetic transparency effect in these two frequency bands. Specific embodiment thirteen:

[0104] The difference between the thirteenth embodiment of the present invention and the twelfth embodiment is that:

[0105] In view of the problems in the background technology, the present invention provides an electromagnetically transparent dual-polarization base station antenna unit, which is structured from top to bottom as a radiator, a dielectric substrate, a feeding structure, and a common metal layer;

[0106] The radiator is obtained by chamfering a circular patch and opening a series of grooves, wherein the groove shapes include: a rectangular long groove, a clamp-shaped groove and a fan-shaped thin groove;

[0107] The rectangular slot is located at the radial line of the circular radiator, and its direction angle is consistent with the ±45° dual polarization direction of the antenna;

[0108] The clamping groove is attached to the radial line and outer circumference of the circular radiator. There are two clamping grooves in the quarter-circle unit of the antenna radiator. One side of the clamping groove is attached to the rectangular long groove mentioned above, and the other side is attached to one side of another clamping groove. The two clamping grooves approximately form a quarter sector;

[0109] The fan-shaped fine groove is a groove opened on the inner patch surrounded by the clamp-shaped groove in a fan shape, close to the clamp-shaped groove.

[0110] The polarizations in two directions of the radiator of the dual-polarization base station antenna unit can be fed by two baluns respectively;

[0111] The two baluns are printed on two dielectric substrates respectively, and the other side of the dielectric substrate is a metal ground, and the middle is spaced due to the interlocking. The two dielectric substrates are perpendicular to each other and are placed perpendicular to the metal ground layer. One dielectric substrate has a groove in the lower part, and the other dielectric substrate has a groove in the upper part, and the two can be interlocked and placed perpendicularly to each other.

[0112] The shape of the balun is approximately "Γ"-shaped, and the structures of the two baluns near each other are connected by a semicircular ring, which can reduce the mutual interference between the baluns near each other.

[0113] The balun has an additional branch on the basis of the overall "Γ" shape, which plays a filtering role, can reduce the out-of-band gain higher than the antenna operating frequency, and reduce the impact on other high-frequency gains in the base station.

[0114] The polarizations in two directions of the radiator of the dual-polarization base station antenna unit can also be fed by two coaxial lines respectively; a pair of dipole units responsible for radiation in one polarization direction are printed on the upper and lower surfaces of the dielectric substrate respectively.

[0115] In one polarization direction, the outer conductor of the coaxial line is connected to one of a pair of dipoles located on the lower surface of the dielectric substrate, and the other of the pair of dipoles located on the upper surface of the dielectric substrate extends the microstrip stub to the position of the coaxial line, and the inner conductor is connected to it;

[0116] In another polarization direction, one of the pair of dipoles located on the lower surface of the dielectric substrate extends the microstrip stub to below the other of the pair of dipoles located on the upper surface of the dielectric substrate, the inner conductor of the coaxial line is connected to the dipole on the lower surface of the dielectric substrate, and the outer conductor is connected to the dipole on the upper surface of the dielectric substrate.

[0117] The inner conductor is connected to the lower radiator of the dielectric substrate, and the extension length of the short stub does not completely cover the coaxial line. The remaining part of the outer conductor can bypass the short stub and connect to the upper radiator of the dielectric substrate.

[0118] Preferably, in the sector-shaped dipole unit, the inner corners are chamfered.

[0119] Based on the same concept, the present invention also provides a base station antenna, comprising at least one electromagnetically transparent dual-polarized base station antenna unit as described in any one of the above and a reflector, wherein the reflector is arranged behind the electromagnetically transparent dual-polarized base station antenna unit and is used for its directional radiation.

[0120] Based on the same concept, the present invention also provides a three-band base station antenna, comprising at least any one of the above-mentioned electromagnetically transparent dual-polarized base station antenna units, and another dual-band antenna is coaxially placed below the electromagnetically transparent antenna. The operating frequency band of the overall antenna structure can cover three frequency bands: 1.7-2.7GHz, 3.3-3.8GHz, and 4.8-5GHz. Each frequency band can radiate normally, and the interference between frequency bands is extremely small.

[0121] The above is only a preferred implementation of an electromagnetically transparent dual-polarized base station antenna. The protection scope of an electromagnetically transparent dual-polarized base station antenna is not limited to the above embodiment. All technical solutions under this idea belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, several improvements and changes without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. An electromagnetically transparent dual-polarized base station antenna, characterized in that: The antenna comprises: a first radiator, a second radiator, a third radiator, a fourth radiator, a dielectric substrate, a first balun feeding structure, a second balun feeding structure and a common metal ground layer; The first balun feeding structure and the second balun feeding structure are printed on the front of the dielectric substrate. The first balun feeding structure is arranged behind the first radiator and the third radiator and connected thereto. The second balun feeding structure is arranged behind the second radiator and the fourth radiator and connected thereto. The two feeding baluns are vertically embedded and embedded in a common metal stratum. A coaxial line is used under the common metal stratum to feed the balun feeding structure. The common metal ground layer is used to reflect the downward radiation energy of the first radiator, the second radiator, the third radiator and the fourth radiator and is connected to the reverse back plates of the first balun feeding structure and the second balun feeding structure as a ground.

2. The antenna according to claim 1, characterized in that: The radiator is obtained by chamfering a circular patch and opening a series of grooves, wherein the groove shapes include: a rectangular long groove, a clamp-shaped groove and a fan-shaped thin groove.

3. The antenna according to claim 2, characterized in that: The rectangular slot is located at the radial line of the circular radiator, and its direction angle is consistent with the ±45° dual polarization direction of the antenna; The clamp-type slot is attached to the radial line and the outer circumference of the circular radiator. There are two clamp-type slots in the quarter-circle unit of the antenna radiator. One side of the clamp-type slot is attached to the rectangular long slot, and the other side is attached to one side of another clamp-type slot. The two clamp-type slots form a quarter-sector. The fan-shaped fine groove is a groove opened on the inner patch surrounded by the clamp-shaped groove in a fan shape, close to the clamp-shaped groove.

4. The antenna according to claim 1, characterized in that: The polarizations of the radiator in two directions are fed by two balun feeding structures respectively; the two balun feeding structures are printed on two dielectric substrates respectively, the other side of the dielectric substrate is a common metal layer, the middle is separated by air due to the embedding, the two dielectric substrates are perpendicular to each other and are placed perpendicular to the common metal layer; a dielectric substrate has a groove in the lower part, and the other dielectric substrate has a groove in the upper part, and the two can be embedded and placed perpendicular to each other.

5. The antenna according to claim 4, characterized in that: The balun feeding structure is in the shape of "Γ", and the two balun feeding structures are connected in a semicircular ring to reduce the mutual interference between the baluns in close proximity. The balun feeding structure adds a branch on the basis of the overall "Γ" shape. The polarizations of the radiator in two directions are fed by two coaxial cables respectively; a pair of dipole units responsible for radiation in one polarization direction are printed on the upper and lower surfaces of the dielectric substrate respectively.

6. The antenna according to claim 1, characterized in that: In one polarization direction, the outer conductor of the coaxial line is connected to one of a pair of dipoles located on the lower surface of the dielectric substrate, and the other of the pair of dipoles located on the upper surface of the dielectric substrate extends the microstrip stub to the position of the coaxial line, and the inner conductor is connected to it; In another polarization direction, one of the pair of dipoles located on the lower surface of the dielectric substrate extends the microstrip stub to below the other of the pair of dipoles located on the upper surface of the dielectric substrate, the inner conductor of the coaxial line is connected to the dipole on the lower surface of the dielectric substrate, and the outer conductor is connected to the dipole on the upper surface of the dielectric substrate.

7. The antenna according to claim 6, characterized in that: The inner conductor is connected to the lower radiator of the dielectric substrate. The extension length of the short stub does not completely cover the coaxial line. The remaining part of the outer conductor is able to bypass the short stub and connect to the upper radiator of the dielectric substrate. In the fan-shaped dipole unit, the inner corners are chamfered.

8. A base station antenna, characterized in that: The antenna comprises the electromagnetically transparent dual-polarized base station antenna as described in claims 1-7 and a reflector, wherein the reflector is arranged behind the magnetically transparent dual-polarized base station antenna and is used for directional radiation thereof.

9. A triple-band base station antenna, characterized in that: The antenna includes the electromagnetically transparent dual-polarized base station antenna as described in claims 1-7, and another dual-frequency antenna is placed coaxially with the electromagnetically transparent antenna below it. The working frequency band of the overall antenna structure can cover three frequency bands: 1.7-2.7GHz, 3.3-3.8GHz and 4.8-5GHz. Each frequency band can radiate normally, and the interference between frequency bands is extremely small.

10. A method for designing an electromagnetically transparent dual-polarized base station antenna, characterized in that: The method is implemented based on the magnetically transparent dual-polarized base station antenna as described in claims 1-7.

Images