Low profile dual-polarized omni-directional ceiling antenna

Abstract

The application relates to the technical field of antennas, in particular to a low-profile dual-polarization omnidirectional ceiling antenna, which comprises a reflecting plate, an electric bridge base is arranged on the upper side of the reflecting plate, an impedance transition base is arranged at the upper end of the electric bridge base, a cross center shaft with a circular arc surface is arranged at the top end of the impedance transition base, a vertical cavity is arranged in the center of the four, and a vertical dipole is arranged in the vertical cavity, a horizontally polarized circular ring is sleeved on the periphery of the electric bridge base, the circular ring is attached to the circular arc surface through a fixing hole to realize radial limiting, a few-shaped clamping groove with an elastic clamping cantilever is arranged on the edge, four vertical sliding rails are arranged on the outer side of the electric bridge base, the sliding rails are slidingly connected with sleeve cylinders provided with fastening bolts, and the circular ring is axially adjusted through the clamping groove and the sleeve cylinder, the radial positioning is accurate and the assembly is stable, low profile and wideband compatibility are realized, the radiation non-circularity is effectively reduced, the communication blind area is eliminated, and the indoor suspended ceiling narrow installation space is adapted.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, specifically to a low-profile dual-polarized omnidirectional ceiling-mounted antenna. Background Technology

[0002] Antennas are core components of wireless communication systems, enabling bidirectional conversion between guided waves and free-space electromagnetic waves. They are widely used in various engineering systems that rely on electromagnetic waves to transmit information. Omnidirectional ceiling antennas, as key devices for indoor wireless signal coverage, are limited by indoor ceiling installation space and require low-profile, miniaturized designs. To improve communication capacity and anti-interference capabilities, dual-polarization design has become the mainstream direction. However, dual-polarized antennas have more complex structures and are more difficult to design. Existing patch-type dual-polarized ceiling antennas have a core technical contradiction: low-profile miniaturization design leads to narrower bandwidth, which cannot meet the needs of broadband communication. Ensuring high bandwidth requires increasing the antenna size, which is difficult to adapt to indoor installation conditions.

[0003] To address the aforementioned problems, existing technologies offer several solutions. For example, patent application CN202211112625.8 discloses a low-profile dual-polarized antenna and electronic device. This application reveals the following solution: By employing a low-profile stacked structure, coupled resonance, and ground-floor multiplexing antenna design, the structural compactness and operating bandwidth of the dual-polarized omnidirectional ceiling antenna are fundamentally improved. This eliminates the contradiction between low profile and large bandwidth, and the difficulty in balancing size and bandwidth performance inherent in traditional patch-type dual-polarized ceiling antennas. Furthermore, through dual-polarized orthogonal feeding and integrated radiation design… The design can stably achieve omnidirectional radiation guidance, dual-polarized signal transmission and reception, and broadband communication functions, alleviating the problem of low wireless communication efficiency caused by narrow bandwidth and poor polarization isolation. It can be adapted to stable operation and use in indoor ceiling installation and low-profile miniaturized communication scenarios. However, this solution has certain limitations in actual use: multiple parasitic plates surround the coupling unit, requiring complete symmetry, consistent spacing, and no contact. If even one plate is offset or the gap size is inconsistent during processing or assembly, the radiation will be asymmetrical, the non-circularity will increase directly, the signal will be strong in one direction and weak in the other, resulting in a large area of ​​communication dead zone. Summary of the Invention

[0004] The purpose of this invention is to provide a low-profile dual-polarized omnidirectional ceiling-mounted antenna to solve the problem of antenna non-circularity spikes.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A low-profile dual-polarized omnidirectional ceiling-mounted antenna includes a reflector, a bridge base on the upper side of the reflector, an impedance transition base at the upper end of the bridge base, a cross-shaped central axis at the top of the impedance transition base, and an arc-shaped surface at the edge of the cross-shaped central axis. A vertically penetrating central cavity is formed at the center of each of the cross-shaped central axis, the impedance transition base, the bridge base, and the reflector. A vertical pole is disposed within the central cavity. A horizontally polarized ring is fitted around the bridge base, and a fixing hole is disposed at the center of the horizontally polarized ring. The hole achieves radial positioning of the horizontally polarized ring by fitting against the arc surface. Multiple slots are symmetrically formed on the edge of the horizontally polarized ring, and the multiple slots have elastic deformation space. Four vertical slide rails are provided on the outer side of the bridge base. There is a power supply structure inside the vertical slide rails. An outer sleeve is slidably connected to each vertical slide rail. A locking hole is provided on the right side of the outer sleeve, and a fastening bolt is provided in the locking hole. The outer sleeve is slidably connected to the vertical slide rail. The horizontally polarized ring is connected to the outer sleeve through the slots and can be adjusted axially along the vertical slide rail with the outer sleeve.

[0006] Using a reflector as the core supporting foundation, a bridge base and an impedance transition base are sequentially arranged on the upper side of the reflector. A cross-shaped central axis with a rounded edge is placed at the top of the impedance transition base. A vertically penetrating central cavity is created at the center of the cross-shaped central axis, the impedance transition base, the bridge base, and the reflector, and a vertical pole is placed within the cavity. A horizontally polarized ring with a fixing hole in the center is fitted around the bridge base. The tight fit between the rounded edge of the cross-shaped central axis and the fixing hole of the horizontally polarized ring achieves horizontal polarization. The precise radial positioning of the polarization ring is achieved by creating multiple axisymmetric slots with elastic deformation space along the edge of the horizontal polarization ring. Four vertical slide rails are positioned on the outside of the bridge base, and a slidable outer sleeve is mounted on each slide rail. A locking hole with a fastening bolt is located on the right side of the outer sleeve, allowing the horizontal polarization ring to be flexibly adjusted in axial height via the cooperation of the outer sleeve and the slots. This structural design fundamentally avoids the problems of increased radiation non-circularity and signal distortion caused by radial eccentricity and fixed height in traditional dual-polarization antennas. To address the issue of uneven coverage, the precise radial limiting design ensures that the horizontal polarization ring and the central vertical pole always maintain ideal coaxiality, resolving defects such as radiation pattern distortion and local communication blind spots caused by assembly misalignment. The axially adjustable assembly structure allows for flexible adjustment of the height of the horizontal polarization ring according to the actual operating frequency band, significantly expanding the antenna's operating bandwidth and debugging adaptability. The hierarchical base layout and compact component integration design effectively compress the overall axial dimensions of the antenna, perfectly achieving the design goals of low profile and miniaturization. It can easily adapt to the narrow installation space of indoor ceilings, while the elastic deformation space of the slot improves the convenience of assembly and connection stability, enabling reliable assembly without complex welding. The overall design not only solves the core contradiction of traditional dual-polarization ceiling antennas being unable to simultaneously achieve low profile miniaturization and broadband communication, but also significantly improves the uniformity of dual-polarization omnidirectional radiation, signal transmission stability, and polarization isolation through multiple advantages such as precise positioning, flexible adjustment, and compact integration, comprehensively optimizing the quality and effect of indoor wireless signal coverage.

[0007] Preferably, the slot is a U-shaped slot, and an avoidance notch is provided in the slot. The avoidance notch is U-shaped and located inside the slot. The two sides of the avoidance notch extend into the slot to form elastic clamping arms, which are made of elastic metal.

[0008] By specifically designing the slot on the edge of the horizontal polarization ring as a U-shaped slot, and creating a U-shaped clearance notch on the inner side of the U-shaped slot, the two sides of the clearance notch naturally extend into the slot to form an integrated elastic clamping cantilever. The elastic clamping cantilever is made of elastic metal. The regular structure of the U-shaped slot provides a stable and evenly stressed fit for the connection and assembly between the horizontal polarization ring and the outer sleeve. The spatial layout of the U-shaped clearance notch provides ample and reasonable elastic deformation space for the elastic clamping cantilever, effectively avoiding stress concentration, deformation jamming, or even structural breakage during clamping assembly, axial adjustment, and long-term operation. The integrated elastic clamping cantilever, formed by the extension of the two sides of the clearance notch, can form a weld-free, quick-installation elastic clamping fit with the outer sleeve, significantly simplifying the antenna assembly process. While ensuring the tightness and stability of the connection, the elastic metal material gives the elastic clamping cantilever a durable and stable elastic clamping force, excellent structural strength and excellent fatigue deformation resistance. This ensures that the cantilever can maintain a stable clamping state under various complex working conditions such as long-term repeated use, equipment vibration, and thermal expansion and contraction caused by temperature changes, without elastic failure, loosening or deformation. Thus, from the root of the structural design, it effectively eliminates problems such as radial displacement, loosening or misalignment of the horizontal polarization ring during axial height adjustment or long-term operation, continuously ensuring the ideal coaxiality between the horizontal polarization ring and the central vertical pole, stabilizing the antenna assembly accuracy and positioning effect, and working together to reduce the antenna radiation non-circularity and eliminate communication blind spots. At the same time, it takes into account the ease of assembly and structural reliability, providing a solid structural support for the antenna to achieve low profile, wide bandwidth, and dual-polarization omnidirectional uniform radiation.

[0009] Preferably, the four vertical slide rails are arranged circumferentially at 90° intervals, and the feeding structure within the vertical slide rails forms a progressive phase-shift differential feed with a phase difference of 90°.

[0010] By arranging four vertical slide rails evenly in a circular pattern at 90° intervals, and designing a progressive phase-shift differential feed structure with a 90° phase difference within the feed structure of the vertical slide rails, this symmetrical and standardized feed layout design can ensure the orthogonality and phase accuracy of the dual-polarization signals from the feed head. This ensures that the excitation phases of the horizontal and vertical polarization signals are uniform and consistent, without interference, effectively improving the dual-polarization isolation and signal polarization purity, and avoiding radiation pattern distortion and signal coverage caused by feed phase deviation and layout asymmetry. To address the issue of uneven radiation intensity, this antenna further reduces radiation non-circularity and eliminates communication blind spots from an electrical performance perspective. Utilizing the precise radial positioning and coaxiality assurance of the horizontally polarized ring, the symmetrical excitation effect of the 90° progressive phase-shift differential feed is fully realized. Simultaneously, the adjustable axial height of the horizontally polarized ring allows for precise matching of the feed phase and radiation spacing according to frequency band requirements. This collaboratively solves the technical challenges of traditional dual-polarized antennas, such as the inability to simultaneously achieve low profile and wide bandwidth, and high radiation non-circularity, further enhancing the overall communication stability and signal coverage quality of the antenna.

[0011] Preferably, the impedance transition base has a stepped structure that gradually narrows from bottom to top, and the impedance transition base adopts three steps, with each step having an equal height controlled between 3mm and 5mm.

[0012] By designing the impedance transition base as a stepped structure that gradually narrows from bottom to top, and employing a three-step form, while precisely controlling the height of each step within a uniform range of 3mm to 5mm, this structured and parameterized precise design can construct a smooth, continuous, uniform, and stable impedance gradient transmission path between the vertical pole and the bridge base. The gradually narrowing stepped shape perfectly matches the impedance matching transmission law of electromagnetic waves in the microwave band, effectively avoiding severe reflection, scattering, and energy loss of radio frequency signals in the base transmission section. The three-step structure with equal height ensures that the impedance gradient process is without abrupt changes or deviations. The 3mm to 5mm steps... The stepped height ensures effective impedance transition without increasing the axial height of the base. Simultaneously, this stepped impedance transition base forms a highly compatible structural fit with the central cavity that runs through the cross-shaped central axis, the impedance transition base, the bridge base, and the reflector. This provides stable support and an ideal signal transmission environment for the vertical poles within the central cavity, significantly reducing the antenna's voltage standing wave ratio (VSWR) and expanding the operating bandwidth. It ensures both the high efficiency and stability of vertical pole signal transmission, while the hierarchical, compact layout further reduces the overall axial dimensions of the antenna. Furthermore, precise impedance gradient matching optimizes the transmission quality and radiation stability of the dual-polarized signal.

[0013] Preferably, symmetrical conical blocks are provided on the left and right sides of the upper end of the outer sleeve, and a first conical surface is provided on the conical block. The taper of the first conical surface is 1:3. An installation groove is provided at the lower end of the conical block, and the installation groove is engaged with the elastic clamping cantilever.

[0014] By symmetrically distributed conical blocks on the left and right sides of the upper end of the outer sleeve, and a first conical surface with a taper of 1:3 on each conical block, and an installation groove adapted to the elastic clamping cantilever at the lower end of the conical block, a precisely matched nested fit structure is formed between the installation groove and the elastic clamping cantilever. The symmetrical conical blocks ensure balanced force distribution during assembly of the outer sleeve and the slot, while the specific 1:3 conical surface provides stable and smooth automatic guidance during assembly, enabling rapid alignment of the horizontally polarized ring and the outer sleeve. This effectively avoids problems such as eccentricity, jamming, and misalignment during assembly, significantly improving assembly efficiency and positioning accuracy. The installation groove at the lower end of the conical block serves as a spring... The elastic clamping cantilever provides limiting and locking space, allowing the elastic clamping action of the elastic clamping cantilever to be precisely applied to the mating interface. This design, together with the zigzag slot, U-shaped clearance notch, and elastic clamping cantilever made of elastic metal, forms a close and complementary effect. It not only relies on the elastic clamping structure to achieve weldless quick assembly and elastic locking, but also further enhances the clamping stability and positioning accuracy of the elastic clamping cantilever through tapered guides and groove limiting. It effectively prevents problems such as loosening, shifting, and radial displacement of the horizontal polarization ring during axial adjustment or long-term use. In turn, it synergistically reduces radiation non-roundness, improves the uniformity of dual-polarization omnidirectional radiation, and optimizes assembly convenience and structural reliability.

[0015] Preferably, the end of the elastic clamping cantilever is provided with an anti-detachment hook.

[0016] By specifically adding an anti-detachment hook to the end of the elastic clamping cantilever, the hook and the elastic clamping cantilever form an integrated composite limiting structure. Utilizing the elastic metal material of the elastic clamping cantilever and the ample elastic deformation space reserved by the U-shaped clearance notch, the anti-detachment hook can smoothly engage and limit the movement of the elastic clamping cantilever as it expands and contracts. Furthermore, the outline of the anti-detachment hook precisely matches the inner wall of the mounting groove at the lower end of the outer sleeve's conical block. After the elastic clamping cantilever is engaged in the mounting groove, it can smoothly embed into the mounting groove, forming a radial stop and axial lock. This design, without affecting the normal elastic deformation and rapid assembly engagement function of the elastic clamping cantilever, adds a long-lasting and reliable anti-detachment barrier to the connection between the horizontally polarized ring and the outer sleeve. Under various complex operating conditions, such as antenna installation and debugging, axial height adjustment of the horizontal polarization ring, long-term vibration operation in indoor environments, and thermal expansion and contraction of components caused by temperature changes, the elastic clamping cantilever effectively constrains the deformation range of the elastic clamping cantilever, completely avoiding failures such as excessive outward expansion, loosening, slippage, or even separation from the outer sleeve. It also prevents radial offset and misalignment of the horizontal polarization ring due to loose connections, continuously ensuring the ideal coaxiality between the horizontal polarization ring and the central vertical pole. This stabilizes the antenna assembly accuracy from the structural root, thereby reducing antenna radiation non-circularity and eliminating communication blind spots. It significantly improves the structural stability and assembly reliability of the antenna during long-term operation, while eliminating the need for additional locking accessories. It achieves a long-lasting and stable anti-detachment locking effect while simplifying the assembly process.

[0017] Preferably, the three-step surface of the impedance transition base is plated with a silver layer, and the impedance transition base is made of high-frequency engineering plastic with a dielectric constant of 2.2 to 3.5.

[0018] By plating a silver layer across the entire surface of the three-step structure and using a high-frequency engineering plastic with a dielectric constant of 2.2–3.5 as the material for the base, the silver layer, with its ultra-high conductivity, significantly reduces the transmission loss and interface reflection of radio frequency signals in the impedance transition section. This results in more uniform conductivity on the step surface and a smoother, more stable impedance transition, preventing signal attenuation, scattering, and standing wave degradation during transmission. Furthermore, the high-frequency engineering plastic with a dielectric constant of 2.2–3.5 exhibits extremely low dielectric loss within the microwave operating frequency band and can precisely balance impedance matching and antenna profile height. It avoids bandwidth contraction due to dielectric parameter imbalance and does not increase the axial size of the antenna. It further enhances the smoothness and matching accuracy of impedance transition from the dual dimensions of conductive process and dielectric material, while significantly improving signal transmission efficiency and radiation stability. It does not destroy the structural foundation laid by the overall compactness and miniaturization of the antenna, and can synergistically optimize the transmission quality of dual-polarized signals. With the radial limiting and axially adjustable core design, it further reduces radiation non-circularity and eliminates communication blind spots, solving the problem that traditional dual-polarized ceiling antennas cannot balance low profile and broadband performance.

[0019] Preferably, microwave absorbing cotton is provided on the reflector, and the microwave absorbing cotton is attached to the upper surface of the reflector.

[0020] By strategically placing microwave absorbing cotton on the reflector and tightly adhering it to the upper surface of the reflector facing the bridge base, impedance transition base, horizontal polarization ring, and vertical poles, a fitted, fully covered microwave absorbing structure is formed. This design can efficiently absorb stray reflected waves, reverse coupling waves, and crosstalk clutter generated on the upper surface of the reflector during antenna operation. It avoids problems such as radiation pattern distortion and decreased omnidirectional radiation uniformity caused by secondary interference from reflected waves. From an electromagnetic performance perspective, it effectively suppresses back-radiated energy leakage, concentrates radiated energy to the indoor signal coverage area, significantly improves the antenna's forward radiation efficiency and gain, and reduces the horizontal poles' crosstalk. It reduces coupling interference between polarized and vertically polarized signals, improves polarization isolation, further reduces radiation non-circularity, eliminates communication blind spots, and provides mechanical protection for internal precision components such as vertical poles, horizontal polarization rings, and impedance transition bases. This prevents component deformation or positioning misalignment due to collisions and vibrations during assembly and use. It is fully compatible with low-profile and miniaturized structural layouts without increasing the axial dimension of the antenna, maximizing the absorption and uniform radiation effect of microwave absorbing cotton. It collaboratively solves the problems of uneven radiation, signal blind spots, and the inability to balance low profile and broadband performance in traditional dual-polarized ceiling antennas, comprehensively improving the antenna's communication stability and indoor wireless signal coverage quality.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By setting an arc surface on the edge of the cross-shaped central axis and setting a fixing hole in the center of the horizontal polarization ring, radial positioning is achieved. A slot with elastic deformation space is opened on the edge of the horizontal polarization ring. Four vertical slide rails are set on the outside of the bridge base and equipped with a sliding outer sleeve and fastening bolts, so that the horizontal polarization ring can be adjusted axially. This solves the problems of soaring non-circularity of traditional antenna radiation and communication blind spots from the assembly source, eliminates radial eccentricity and assembly offset, flexibly adapts to frequency bands to expand bandwidth, achieves low profile miniaturization with compact layout, requires no welding for rapid assembly, perfectly fits the narrow space of indoor ceiling, and ensures uniform and stable dual-polarization omnidirectional radiation.

[0022] 2. By evenly distributing four vertical slide rails in a 90° circle on the outside of the bridge base and forming a 90° progressive phase shift differential feed, and setting the impedance transition base as a three-level equal-height narrow step with a step height of 3mm to 5mm, a silver layer is plated on the surface of the steps and made of high-frequency engineering plastic with a dielectric constant of 2.2 to 3.5, a smooth impedance gradient transmission path is constructed, which solves the industry contradiction of not being able to balance low profile and broadband, and poor polarization isolation, reduces signal loss and VSWR, improves polarization purity and transmission efficiency, and reduces radiation non-circularity from an electrical performance perspective, ensuring efficient and stable transmission and reception of dual-polarized signals.

[0023] 3. By setting a U-shaped clearance notch on the inner side of the zigzag slot to form an elastic metal clamping cantilever, setting a 1:3 cone-shaped block with a mounting groove on the outer sleeve, setting an anti-detachment hook at the end of the cantilever, and covering the surface of the reflector with microwave absorbing cotton, the assembly locking stability is enhanced, preventing loosening and displacement during adjustment and vibration, absorbing stray reflected waves and polarization crosstalk, suppressing back radiation leakage, avoiding component deformation and inner wall damage, and comprehensively improving the long-term operational stability of the antenna, signal coverage quality and overall assembly reliability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the low-profile dual-polarized omnidirectional ceiling-mounted antenna of the present invention; Figure 2 This is a front view of the low-profile dual-polarized omnidirectional ceiling antenna of the present invention; Figure 3 for Figure 2 Cross-sectional view of AA in the middle; Figure 4 This is a schematic diagram of the structure of a horizontally polarized circular ring; Figure 5 This is a schematic diagram of the outer sleeve structure; Figure 6 This is the vertical plane pattern of the horizontal polarization of the low-profile dual-polarized omnidirectional ceiling-mounted antenna of the present invention; Figure 7 This is a vertical plane pattern of the vertical polarization of the low-profile dual-polarized omnidirectional ceiling antenna of the present invention.

[0025] In the diagram: 1. Reflector; 101. Through hole; 102. Microwave absorbing cotton; 2. Central cavity; 3. Bridge base; 4. Impedance transition base; 5. Cross-shaped central axis; 501. Arc surface; 6. Vertical pole; 7. Horizontal polarization ring; 701. Fixing hole; 702. Slot; 8. Vertical slide rail; 801. Outer sleeve; 802. Locking hole; 803. Fastening bolt; 9. Clearance notch; 901. Elastic clamping cantilever; 902. Anti-detachment hook; 10. Conical block; 1001. First conical surface; 1002. Mounting groove; 11. Feed network board; 1101. RF input interface; 1102. Mounting bracket. Detailed Implementation

[0026] Please see Figures 1 to 7 This invention provides a low-profile dual-polarized omnidirectional ceiling-mounted antenna, the technical solution of which is as follows: A low-profile dual-polarized omnidirectional ceiling-mounted antenna includes a reflector 1, on which microwave absorbing cotton 102 is disposed, covering the upper surface of the reflector 1. A feed network board 11 is disposed on the lower side of the reflector 1, and an RF input interface 1101 is disposed on the side of the feed network board 11. A mounting bracket 1102 is disposed on the side of the feed network board 11 away from the RF input interface 1101. Through holes 101 distributed at 90° around the circumference are disposed on the reflector 1. A bridge base 3 is disposed on the upper side of the reflector 1, and an impedance transition base 4 is disposed on the upper end of the bridge base 3. The impedance transition base 4 has a stepped structure that gradually narrows from bottom to top, and the impedance transition base 4 adopts a three-step structure, with each step having an equal height controlled at 3mm. The three-step surface of the impedance transition base 4 is plated with a silver layer, and the impedance transition base 4 is made of high-frequency engineering plastic with a dielectric constant of 3.5. A cross-shaped central shaft 5 is set at the top of the impedance transition base 4, and an arc surface 501 is set at the edge of the cross-shaped central shaft 5. A vertically penetrating central cavity 2 is opened in the center of the cross-shaped central shaft 5, the impedance transition base 4, the bridge base 3, and the reflector 1. A vertical pole 6 is set inside the central cavity 2. The vertical pole 6 is a single vertical columnar conductor made of brass. The lower end of the vertical pole 6 is electrically connected to the feed network board 11. A horizontally polarized ring 7 is sleeved around the bridge base 3. The horizontally polarized ring 7 is made of brass, and a fixing hole 701 is set in the center of the horizontally polarized ring 7. 1. The radial positioning of the horizontally polarized ring 7 is achieved by fitting with the arc surface 501. Multiple slots 702 are symmetrically formed on the edge of the horizontally polarized ring 7. The multiple slots 702 have elastic deformation space. The slots 702 are U-shaped slots 702. The clearance notches 9 are formed in the slots 702. The clearance notches 9 are located inside the slots 702. The two sides of the clearance notches 9 extend into the slots 702 to form elastic clamping cantilever arms 901. The elastic clamping cantilever arms 901 are made of elastic metal. The ends of the elastic clamping cantilever arms 901 are provided with anti-detachment hooks 902. Four vertical slide rails 8 are provided on the outside of the bridge base 3. The power supply structure is an embedded conductive silver strip extending along the vertical slide rails 8. The inner wall of the outer sleeve 801 is inlaid with The outer sleeve 801, which is embedded with an elastic conductive spring, slides along the vertical slide rail 8 axially to adjust the height of the horizontally polarized ring 7. The elastic conductive spring remains in an elastically compressed state and tightly adheres to the surface of the feeding structure, thereby exciting the horizontally polarized ring 7. The vertical slide rail 8 contains a feeding structure, with the four vertical slide rails 8 spaced 90° apart circumferentially. The feeding structures within the vertical slide rails 8 form a progressively phase-shifted differential feed with a 90° phase difference, meaning each pair is strictly 90° out of phase. The feeding network board 11 incorporates a Wilkinson power divider that divides the input signal into four initial in-phase excitation signals with equal amplitude and no coupling attenuation. These signals are synchronously transmitted to the feeding transmission lines inside the four vertical slide rails 8, which are evenly distributed 90° around the outer circumference of the bridge base 3.The feeding structure within the vertical slide rail 8 is a combination of a strip transmission line and a quarter-wavelength phase delay. The four signals ultimately form a standard orthogonal phase sequence of 0°, 90°, 180°, and 270°, completing the stable output of the 90° progressive phase shift differential feed, thus constituting a 90° progressive phase shift differential feed. The lower end of the vertical slide rail 8 extends into the through hole 101 and is electrically connected to the feeding network board 11. An outer sleeve 801 is slidably connected to each vertical slide rail 8, and symmetrical conical blocks 10 are arranged on the left and right sides of the upper end of the outer sleeve 801. The conical block 10 has a first conical surface 1001 with a taper of 1:3. A mounting groove 1002 is provided at the lower end of the conical block 10, which engages with the elastic clamping cantilever 901. A locking hole 802 is provided on the right side of the outer sleeve 801, and a fastening bolt 803 is installed inside the locking hole 802. The outer sleeve 801 is slidably connected to the vertical slide rail 8. The horizontally polarized ring 7 is connected to the outer sleeve 801 through a slot 702 and can be adjusted axially along the vertical slide rail 8 along with the outer sleeve 801.

[0027] Working principle: (Reference) Figures 1 to 7 After the antenna is installed in the indoor ceiling and the radio frequency signal is connected, the radio frequency signal is input to the feed network board 11 through the radio frequency input interface 1101. The feed network board 11 splits the signal to four vertical slide rails 8 that are evenly arranged at 90° on the outer circumference of the bridge base 3. The feed structure inside the vertical slide rail 8 forms a progressive phase shift differential feed with a phase difference of 90°, and synchronously outputs orthogonal and stable vertical polarization and horizontal polarization excitation signals, thus starting the dual-polarization omnidirectional radiation process.

[0028] The excitation signal is transmitted and radiated synchronously in two paths: one signal travels along the central cavity 2 of the vertical cross axis 5, impedance transition base 4, bridge base 3, and reflector 1 to the vertical pole 6. The lower end of the vertical pole 6 is directly electrically connected to the feed network board 11, directly exciting the vertical pole 6 to complete the transmission and reception of vertical polarized signals and spatial radiation. Simultaneously, the other signal is transmitted through the bridge base 3 to the horizontal polarization ring 7 surrounding it, exciting the horizontal polarization ring 7 to complete the stable radiation of horizontal polarized signals. When it is necessary to adapt to different working frequency bands for debugging, loosen the fastening bolt 803 in the locking hole 802 of the outer sleeve 801, slide the outer sleeve 801 along the vertical slide rail 8 axis, and drive the horizontal polarization ring 7 to complete the height adjustment. After adjustment, tighten the fastening bolt 803, and the anti-detachment hook 902 of the elastic clamping cantilever 901 will simultaneously complete the locking, accurately matching the radiation spacing and feed phase of the target frequency band, improving debugging convenience and positioning accuracy.

[0029] When the antenna is operating stably, the 90° progressive phase shift differential feed ensures the orthogonality and phase accuracy of the dual-polarized signal from the feed head, improving polarization isolation and signal purity. The three-stage stepped impedance transition, radial precision limiting, axial adjustable structure, and microwave absorption and clutter suppression work together to continuously ensure uniform and stable dual-polarized omnidirectional radiation and efficient and reliable signal transmission. It is perfectly adapted to the narrow installation space of indoor ceilings, solving the industry problem of not being able to balance low profile and broadband, and uneven radiation.

[0030] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A low-profile dual-polarized omnidirectional ceiling-mounted antenna, comprising a reflector (1), characterized in that, A bridge base (3) is provided on the upper side of the reflector (1). An impedance transition base (4) is provided at the upper end of the bridge base (3). A cross-shaped central axis (5) is provided at the top of the impedance transition base (4). An arc surface (501) is provided on the edge of the cross-shaped central axis (5). A vertically penetrating central cavity (2) is opened in the center of the cross-shaped central axis (5), the impedance transition base (4), the bridge base (3), and the reflector (1). A vertical pole (6) is provided in the central cavity (2). A horizontally polarized ring (7) is sleeved around the bridge base (3). A fixing hole (701) is provided in the center of the horizontally polarized ring (7). The fixing hole (701) achieves horizontal polarization by fitting with the arc surface (501). The radial limit of the ring (7) is provided. Multiple slots (702) are symmetrically opened on the edge of the horizontally polarized ring (7). The multiple slots (702) have elastic deformation space. Four vertical slide rails (8) are provided on the outside of the bridge base (3). There is a power supply structure in the vertical slide rail (8). An outer sleeve (801) is slidably connected to each vertical slide rail (8). A locking hole (802) is provided on the right side of the outer sleeve (801). A fastening bolt (803) is provided in the locking hole (802). The outer sleeve (801) is slidably connected to the vertical slide rail (8). The horizontally polarized ring (7) is connected to the outer sleeve (801) through the slot (702) and can be adjusted along the vertical slide rail (8) axially with the outer sleeve (801).

2. The low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 1, characterized in that, The slot (702) is a U-shaped slot (702), and an avoidance notch (9) is provided in the slot (702). The avoidance notch (9) is U-shaped and located inside the slot (702). The two sides of the avoidance notch (9) extend into the slot (702) to form an elastic clamping cantilever (901). The elastic clamping cantilever (901) is made of elastic metal.

3. The low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 1, characterized in that, The four vertical slide rails (8) are arranged circumferentially at 90° intervals, and the power supply structure in the vertical slide rails (8) forms a progressive phase-shift differential power supply with a phase difference of 90°.

4. The low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 1, characterized in that, The impedance transition base (4) has a stepped structure that gradually narrows from bottom to top, and the impedance transition base (4) adopts three steps, with each step having an equal height controlled between 3mm and 5mm.

5. A low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 2, characterized in that, Symmetrical conical blocks (10) are provided on the left and right sides of the upper end of the outer sleeve (801). A first conical surface (1001) is provided on the conical block (10). The taper of the first conical surface (1001) is 1:

3. An installation groove (1002) is provided at the lower end of the conical block (10). The installation groove (1002) is engaged with the elastic clamping cantilever (901).

6. A low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 2, characterized in that, The end of the elastic clamping cantilever (901) is provided with an anti-detachment barb (902).

7. A low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 4, characterized in that, The three-step surface of the impedance transition base (4) is plated with a silver layer, and the impedance transition base (4) is made of high-frequency engineering plastic with a dielectric constant of 2.2 to 3.

5.

8. A low-profile dual-polarized omnidirectional ceiling-mounted antenna according to claim 1, characterized in that, The reflector (1) is provided with microwave absorbing cotton (102), which is attached to the upper surface of the reflector (1).

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