Wide angle scanning millimeter wave horizontally polarized omni-directional antenna

Abstract

The application relates to the technical field of antennas and discloses a wide-angle scanning millimeter wave horizontally polarized omnidirectional antenna. The antenna comprises a dielectric substrate, first and second excitation ports and a coaxial connector arranged at two ends of the dielectric substrate; a substrate integrated waveguide slot array comprising two rows of I-shaped periodic slots on first and second slotted metal patches and three rows of metalized through holes; a half-mode substrate integrated waveguide; and first and second waveguide transition structures. The horizontally polarized omnidirectional radiation is realized through the combination of the slot mode and the substrate integrated waveguide mode, the beam scanning is realized by means of the leaky wave mode, the open stop band is inhibited and suppressed by means of the inductivity of the impedance matching metalized through hole and the capacitance of the slot, and the wide-angle scanning is realized. The application has the advantages of simple structure, simultaneous realization of H-plane omnidirectional coverage and E-plane wide-angle beam scanning in the millimeter wave frequency band, high gain and satisfaction of the 5G / 6G communication application requirements.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna. Background Technology

[0002] The rapid development of 5G and future 6G communication technologies has placed higher demands on antenna performance. Millimeter-wave bands, with their abundant spectrum resources, can meet the needs of high-bandwidth, high-speed communication and are widely used in 5G communications. Omnidirectional antennas, capable of achieving 360-degree uniform radiation, can be widely used in large-area coverage, point-to-multipoint communication systems. Furthermore, in practical communication scenarios, to achieve more flexible and efficient signal coverage and transmission, antennas need wide-angle scanning capabilities. Wide-angle scanning antennas can dynamically direct signals towards users in different directions, improving system capacity and spectral efficiency.

[0003] A leaky wave antenna is an antenna that guides electromagnetic waves to propagate along a transmission line and gradually radiates energy. By changing the frequency of the excitation signal or other parameters, the radiation beam of a leaky wave antenna can be scanned within a certain angular range. However, current methods generally achieve wide-angle scanning in the E-plane and typically present a directional beam in the H-plane. This results in limited coverage in the H-plane for leaky wave antennas, failing to meet the requirements of some applications with strict requirements for omnidirectional coverage, such as large shopping malls and office buildings in indoor wireless communication, and omnidirectional detection needs in radar systems.

[0004] Regarding antenna polarization, current technologies largely focus on the research and application of vertically polarized omnidirectional antennas. However, in practical communication environments, horizontally polarized omnidirectional antennas possess superior practical value due to their unique polarization diversity characteristics. In environments with multipath propagation, horizontally polarized waves can effectively reduce the impact of multipath interference. Horizontally polarized electromagnetic waves are less affected by ground reflection because their electric field is parallel to the ground. Ground reflection results in significant polarization loss and substantial amplitude attenuation of the reflected wave, and total reflection is less likely to occur, making interference more controllable. Furthermore, in environments with numerous horizontal obstacles, the propagation of horizontally polarized waves is less affected by obstruction, resulting in less signal attenuation and interference, effectively improving communication quality and reliability.

[0005] In summary, existing technologies have shortcomings in achieving H-plane omnidirectional radiation and horizontal polarization of millimeter-wave antennas, and a new technical solution is needed to address these issues in order to meet the growing demand for millimeter-wave communication applications. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna, aiming to solve the issues of existing millimeter-wave antennas having H-plane omnidirectional coverage, E-plane wide-angle beam scanning, and limited horizontal polarization modes.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna, comprising:

[0009] A dielectric substrate having a first excitation port and a second excitation port, as well as a first coaxial connector and a second coaxial connector at both ends;

[0010] The substrate-integrated waveguide slot array includes a first row of "I"-shaped periodic slots disposed on a first slotted metal patch and a second row of "I"-shaped periodic slots disposed on a second slotted metal patch, and three rows of metallized vias; the three rows of metallized vias are disposed through the dielectric substrate, and their two ends are respectively connected to the first slotted metal patch and the second slotted metal patch.

[0011] A half-mode substrate integrated waveguide includes a first slotted metal patch and a second slotted metal patch, as well as a second row of metallized vias;

[0012] The first waveguide transition structure has its two ends connected to the first grounded coplanar waveguide and the first substrate integrated waveguide, respectively.

[0013] The second waveguide transition structure has its two ends connected to the second grounded coplanar waveguide and the second substrate integrated waveguide, respectively.

[0014] In some embodiments, the first excitation port and the second excitation port are configured as radio frequency signal input terminals or impedance matching terminals as required; the first coaxial connector at the bottom end and the second coaxial connector at the top end of the dielectric substrate are used to realize a detachable, low-loss connection between the antenna and the transmission line; the first ground coplanar waveguide, the first waveguide transition structure, and the first substrate integrated waveguide above the first coaxial connector are connected in sequence to realize low-loss transmission of radio frequency signals and transmission mode adaptation; the second ground coplanar waveguide, the second waveguide transition structure, and the second substrate integrated waveguide below the second coaxial connector are connected in sequence to realize low-loss transmission of radio frequency signals and transmission mode adaptation.

[0015] In some embodiments, the first ground coplanar waveguide and the second ground coplanar waveguide are distributed in a mirror symmetric manner at both ends of the dielectric substrate, the first waveguide transition structure and the second waveguide transition structure are distributed in a mirror symmetric manner at both ends of the dielectric substrate, and the first substrate integrated waveguide and the second substrate integrated waveguide are distributed in a mirror symmetric manner at both ends of the substrate integrated waveguide slot array.

[0016] In some embodiments, the wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna further includes a first slotted metal patch disposed on the left surface of the dielectric substrate and a second slotted metal patch disposed on the right surface; the first slotted metal patch has two symmetrically distributed gradient horn-shaped slots at its upper and lower ends, and a first row of "I"-shaped periodic slots in the middle for efficient radiation of radio frequency energy from the left surface; the second slotted metal patch has rectangular metal patches at its upper and lower ends, serving as the ground plane of the feed network, and a second row of "I"-shaped periodic slots in the middle for efficient radiation of radio frequency energy from the right surface.

[0017] In some embodiments, the first row of "I"-shaped periodic slots and the second row of "I"-shaped periodic slots are symmetrically distributed on both surfaces of the dielectric substrate, and together they are used to achieve horizontal polarization omnidirectional radiation of the antenna. The shapes of the first row of "I"-shaped periodic slots and the second row of "I"-shaped periodic slots can be changed to "1", "L" or "Z" shapes, and the antenna gain and scanning rate can be controlled by adjusting the slot structure.

[0018] In some embodiments, the substrate integrated waveguide slot array further includes a first row of metallized vias, a second row of metallized vias, and a third row of impedance matching metallized vias disposed on a dielectric substrate; the first row of metallized vias and the second row of metallized vias control the leakage of radio frequency energy, and the antenna operating frequency band and radiation characteristics can be changed by adjusting the spacing between the two rows of metallized vias; the third row of impedance matching metallized vias and the periodic slots provide inductive and capacitive properties, respectively, for suppressing the open stopband.

[0019] In some embodiments, the half-mode substrate integrated waveguide is disposed on the right side of the substrate integrated waveguide slot array and shares the second row of metallized vias with the substrate integrated waveguide slot array; the width of the wide wall of the half-mode substrate integrated waveguide can be adjusted to control the non-circularity of the omnidirectional radiation of the antenna.

[0020] In some embodiments, the wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna includes a row of periodic array elements; the array elements consist of slotted substrate integrated waveguides and half-mode substrate integrated waveguides, including a pair of slots symmetrically etched on metal patches on both sides of a dielectric substrate and an impedance-matching metallized via.

[0021] In some embodiments, the substrate integrated waveguide slot array consists of 19 array elements, each array element having a period of 6.75 mm, a longitudinal slot length of 4 mm and a width of 0.2 mm, a transverse slot length of 1.2 mm and a width of 0.2 mm, all metallized vias having a diameter of 0.5 mm, a via spacing of 0.75 mm, and a spacing of 5 mm between the first row of metallized vias and the second row of metallized vias.

[0022] In some embodiments, the dielectric substrate is made of Rogers RO4003C material with a dielectric constant of 3.55, a loss tangent of 0.0027, and dimensions of 151.45 × 14 × 0.508 mm³. The antenna operates in the frequency band of 23-28.6 GHz, with a reflection coefficient of less than -10 dB, a transmission coefficient of less than -12 dB, and a peak gain of 12 dBi within this band. It maintains omnidirectional radiation and low non-circularity in the H-plane, and achieves a wide-angle beam scanning of 110° from 35° to 145° through the first excitation port and the second excitation port, respectively, in the E-plane.

[0023] The beneficial effects of this invention are as follows: This invention discloses a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna. The antenna achieves horizontal polarization omnidirectionality through a clever combination of slotted mode and substrate-integrated waveguide mode, while simultaneously utilizing a leaky wave mode to achieve beam scanning characteristics. Its open-stopband problem is effectively suppressed by canceling out the inductance of the impedance-matched metallized via with the capacitance of the slot, thereby achieving wide-angle scanning characteristics. This invention realizes an antenna with horizontally polarized omnidirectional radiation characteristics. Its structure is simple, and it can simultaneously achieve H-plane omnidirectional coverage and E-plane wide-angle beam scanning in the millimeter-wave band while maintaining high gain, meeting the growing demands of millimeter-wave communication applications. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural schematic diagram of a millimeter-wave horizontally polarized omnidirectional antenna in one embodiment of the present invention.

[0025] Figure 2 This is a perspective view of a millimeter-wave horizontally polarized omnidirectional antenna according to an embodiment of the present invention.

[0026] Figure 3 This is a front view of a millimeter-wave horizontally polarized omnidirectional antenna according to an embodiment of the present invention.

[0027] Figure 4 This is a three-dimensional structural diagram of a millimeter-wave horizontally polarized omnidirectional antenna array element in one embodiment of the present invention.

[0028] Figure 5 This is the dispersion curve of a millimeter-wave horizontally polarized omnidirectional antenna array element in one embodiment of the present invention.

[0029] Figure 6 This is a schematic diagram of the simulation results of the reflection coefficient and transmission coefficient of a millimeter-wave horizontally polarized omnidirectional antenna in one embodiment of the present invention.

[0030] Figure 7 This is a schematic diagram of the gain simulation results of a millimeter-wave horizontally polarized omnidirectional antenna in one embodiment of the present invention.

[0031] Figure 8The radiation patterns of the millimeter-wave horizontally polarized omnidirectional antenna at 23 GHz, 24 GHz, 26 GHz and 28.6 GHz respectively, when excited by the first excitation port, are shown in one embodiment of the present invention.

[0032] Figure 9 The radiation patterns of the millimeter-wave horizontally polarized omnidirectional antenna at 23 GHz, 24 GHz, 26 GHz and 28.6 GHz respectively, when excited by the second excitation port, are shown in one embodiment of the present invention.

[0033] Wherein: S1-first excitation port, S2-second excitation port, A1-first ground coplanar waveguide, A2-second ground coplanar waveguide, B1-first waveguide transition structure, B2-second waveguide transition structure, C1-first substrate integrated waveguide, C2-second substrate integrated waveguide, D1-substrate integrated waveguide slot array, D2-half-mode substrate integrated waveguide, P1-first coaxial connector, P2-second coaxial connector, H1-dielectric substrate, M1-first slotted metal patch, M2-second slotted metal patch, L1-first row of "I"-shaped periodic slots, L2-second row of "I"-shaped periodic slots, E1-first row of metallized vias, E2-second row of metallized vias, E3-third row of impedance matching metallized vias. Detailed Implementation

[0034] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0035] A leaky wave antenna is an antenna that guides electromagnetic waves to propagate along a transmission line and gradually radiates energy. By changing the frequency or other parameters of the excitation signal, the radiation beam of a leaky wave antenna can be scanned within a certain angular range. However, current methods generally achieve wide-angle scanning in the E-plane and typically exhibit directional beams in the H-plane. This results in limited coverage of the leaky wave antenna in the H-plane, failing to meet the requirements of some applications with strict requirements for omnidirectional coverage.

[0036] Regarding antenna polarization, existing technologies largely focus on the research and application of vertically polarized omnidirectional antennas. However, in practical communication environments, horizontally polarized omnidirectional antennas, due to their unique polarization diversity characteristics, possess superior practical value in certain scenarios. In environments with multipath propagation, horizontally polarized waves can effectively reduce the impact of multipath interference. Horizontally polarized electromagnetic waves are less affected by ground reflection because their electric field is parallel to the ground. Ground reflection results in high polarization loss, significant amplitude attenuation of the reflected wave, and a low likelihood of total reflection, making interference more controllable.

[0037] In fact, millimeter-wave antennas based on leaky wave structures generally have beam scanning characteristics in the E-plane and directional beams in the H-plane. Further research is needed to achieve millimeter-wave horizontally polarized antennas that can simultaneously achieve wide-angle beam scanning in the E-plane and omnidirectional radiation in the H-plane.

[0038] To address the technical problems in the background art, this invention provides a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna. This horizontally polarized omnidirectional antenna achieves its purpose through a clever combination of slot mode and substrate integrated waveguide mode, while simultaneously utilizing a leaky wave mode to achieve beam scanning characteristics. Its open-stopband problem is effectively suppressed by canceling out the inductance of the impedance-matched metallized via with the capacitance of the slot, thus realizing a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna.

[0039] Please also refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 This invention provides a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna, comprising:

[0040] The dielectric substrate H1 has a first excitation port S1 and a second excitation port S2, as well as a first coaxial connector P1 and a second coaxial connector P2 at both ends.

[0041] The substrate integrated waveguide slot array D1 includes a first row of "I"-shaped periodic slots L1 disposed on the first slotted metal patch M1 and a second row of "I"-shaped periodic slots L2 disposed on the second slotted metal patch M2, and three rows of metallized vias E1, E2, and E3; the three rows of metallized vias E1, E2, and E3 are disposed through the dielectric substrate H1, and their two ends are respectively connected to the first slotted metal patch M1 and the second slotted metal patch M2;

[0042] The half-mode substrate integrated waveguide D2 includes a first slotted metal patch M1, a second slotted metal patch M2, and a second row of metallized vias E2.

[0043] The first waveguide transition structure B1 is connected at both ends to the first grounded coplanar waveguide A1 and the first substrate integrated waveguide C1, respectively.

[0044] The second waveguide transition structure B2 is connected at both ends to the second grounded coplanar waveguide A2 and the second substrate integrated waveguide C2, respectively.

[0045] In the embodiments provided by this invention, the first excitation port S1 and the second excitation port S2 are configured as radio frequency signal input terminals or impedance matching terminals as required; the first coaxial connector P1 at the bottom end and the second coaxial connector P2 at the top end of the dielectric substrate H1 are used to realize a detachable, low-loss connection between the antenna and the transmission line; the substrate integrated waveguide slot array D1 is used to realize omnidirectional radiation in the H-plane and wide-angle beam scanning in the E-plane; the half-mode substrate integrated waveguide D2 is used to adjust the non-circularity of the antenna radiation. By adjusting the shape and size of the radiation slots, the leakage mode can be flexibly adjusted, effectively controlling the direction and shape of the radiation beam.

[0046] The first excitation port S1, the first coaxial connector P1, the first ground coplanar waveguide A1, the first waveguide transition structure B1, and the first substrate integrated waveguide C1 are connected in sequence to realize low-loss transmission and transmission mode adaptation of radio frequency signals from the first excitation port S1 to the substrate integrated waveguide slot array D1, or to absorb the remaining radio frequency energy radiated on the substrate integrated waveguide slot array D1.

[0047] The second excitation port S2, the second coaxial connector P2, the second ground coplanar waveguide A2, the second waveguide transition structure B2, and the second substrate integrated waveguide C2 are connected in sequence to realize low-loss transmission and transmission mode adaptation of radio frequency signals from the second excitation port S2 to the substrate integrated waveguide slot array D1, or to absorb the remaining radio frequency energy radiated on the substrate integrated waveguide slot array D1.

[0048] The antenna of this invention has excellent characteristics of horizontal polarization, H-plane omnidirectional coverage and E-plane wide beam scanning. Its structure is simple and easy to integrate, which can greatly improve the coverage and connection performance of millimeter-wave wireless communication systems.

[0049] The first grounded coplanar waveguide A1, the first waveguide transition structure B1, the first substrate integrated waveguide C1, the second grounded coplanar waveguide A2, the second waveguide transition structure B2, and the second substrate integrated waveguide C2 constitute the antenna's feed network.

[0050] Compared with existing technologies, this invention provides a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna. It achieves beam scanning characteristics through a clever combination of slotted mode and substrate-integrated waveguide mode, while utilizing a leaky wave mode. The open-stopband problem is effectively suppressed by canceling out the inductance of the impedance-matched metallized via with the capacitance of the slot, thus realizing wide-angle scanning characteristics. This invention realizes an antenna with horizontally polarized omnidirectional radiation characteristics. Its structure is simple, and it can simultaneously achieve H-plane omnidirectional coverage and E-plane wide-angle beam scanning in the millimeter-wave band while maintaining high gain, making it valuable for various millimeter-wave applications.

[0051] In some embodiments, the first grounded coplanar waveguide A1 and the second grounded coplanar waveguide A2 are distributed in a mirror symmetric manner at both ends of the dielectric substrate H1, the first waveguide transition structure B1 and the second waveguide transition structure B2 are distributed in a mirror symmetric manner at both ends of the dielectric substrate H1, and the first substrate integrated waveguide C1 and the second substrate integrated waveguide C2 are distributed in a mirror symmetric manner at both ends of the substrate integrated waveguide slot array D1.

[0052] In some embodiments, the wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna further includes a first slotted metal patch M1 disposed on the left surface of the dielectric substrate H1 and a second slotted metal patch M2 disposed on the right surface, and the storage and leakage of radio frequency energy are controlled by the first slotted metal patch M1 and the second slotted metal patch M2.

[0053] Specifically, the first slotted metal patch M1 has two symmetrically distributed, tapered horn-shaped slots at its top and bottom ends. The tapered horn-shaped structure enables the transmitted electromagnetic wave mode to be converted from the quasi-TEM mode to the TE mode. The middle section has a first row of "I"-shaped periodic slots L1 for efficient radiation of radio frequency energy from the left surface. The second slotted metal patch M2 has rectangular metal patches at its top and bottom ends, serving as the ground plane for the feed network. The middle section has a second row of "I"-shaped periodic slots L2 for efficient radiation of radio frequency energy from the right surface.

[0054] In some embodiments, the first row of "I"-shaped periodic slots L1 and the second row of "I"-shaped periodic slots L2 are symmetrically distributed on both surfaces of the dielectric substrate H1, and together they are used to achieve horizontal polarization omnidirectional radiation of the antenna.

[0055] The shape of the first row of "I"-shaped periodic slots L1 and the second row of "I"-shaped periodic slots L2 can be changed to "1", "L" or "Z" shape. The gain and scanning rate of the antenna can be controlled by adjusting the slot structure.

[0056] In some embodiments, the substrate integrated waveguide slot array D1 further includes a first row of metallized vias E1, a second row of metallized vias E2, and a third row of impedance matching metallized vias E3 disposed on the dielectric substrate H1.

[0057] The first row of metallized vias E1 and the second row of metallized vias E2 are equivalent to the sidewalls of the waveguide, controlling the leakage of radio frequency energy. By adjusting the spacing between the two rows of metallized vias E1 and E2, the antenna's operating frequency band and radiation characteristics can be changed.

[0058] The third row of impedance matching metallized vias E3 and the periodic slots provide inductive and capacitive properties, respectively, to suppress the open stopband.

[0059] In some embodiments, the half-mode substrate integrated waveguide D2 is disposed on the right side of the substrate integrated waveguide slot array D1, and shares the second row of metallized vias E2 with the substrate integrated waveguide slot array D1.

[0060] The width of the wide wall of the half-mode substrate integrated waveguide D2 can be adjusted to control the non-circularity of the antenna's omnidirectional radiation.

[0061] In some embodiments, the wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna includes a row of periodic array elements.

[0062] like Figure 4 As shown, the array element consists of a slotted substrate integrated waveguide and a half-mode substrate integrated waveguide D2, including a pair of slots symmetrically etched on metal patches on both sides of the dielectric substrate H1 and an impedance matching metallized via.

[0063] Based on this array element structure, a leaky beam mode is realized, and wide-angle beam scanning is achieved by using backward scanning characteristics.

[0064] Specifically, the substrate integrated waveguide slot array D1 includes multiple sets of periodically arranged array elements, which are obtained by etching a row of periodic slots on the first slotted metal patch M1 and the second slotted metal patch M2, respectively.

[0065] In a preferred embodiment, the substrate integrated waveguide slot array D1 consists of 19 array elements. Each array element consists of a slotted substrate integrated waveguide and a half-mode substrate integrated waveguide D2. The period of each array element is 6.75 mm, the longitudinal slot length is 4 mm and the width is 0.2 mm, the transverse slot length is 1.2 mm and the width is 0.2 mm, all metallized vias have a diameter of 0.5 mm, the via spacing is 0.75 mm, and the spacing between the first row of metallized vias E1 and the second row of metallized vias E2 is 5 mm. Based on these parameters, TE can be calculated. 10 The first cutoff frequency is 17.13 GHz, and the second cutoff frequency is 34.28 GHz, to ensure single-mode operation in the operating frequency band (23-28.6 GHz). By coordinating the adjustment of the pair element period and the slot size, the antenna's dispersion characteristics are effectively controlled, thereby achieving precise control of the radiated beam.

[0066] The effective integration of the substrate integrated waveguide slot array D1 and the half-mode substrate integrated waveguide D2 enables dual-mode operation, namely slot mode and substrate integrated waveguide mode. Unlike traditional single-slot leaky wave antennas, this invention etches a pair of symmetrical "I"-shaped slots on both sides of the dielectric substrate H1 metal patches. The "I"-shaped slots are equivalent to vertically placed magnetic dipoles. Therefore, based on this design, a horizontally polarized omnidirectional radiating millimeter-wave antenna can be realized.

[0067] Figure 5 The dispersion curves of the antenna array elements are shown. In this example, the operating frequency band of the backward scanning region is used. As can be seen from the figure, at the open stopband location (near the phase constant of 0), the phase constant curve is linear, and the attenuation constant curve is flat, thus the open stopband is effectively suppressed. It is evident that the inductive property of the impedance-matched metallized via and the capacitive property of the slot cancel each other out, effectively solving the open stopband problem and facilitating the realization of wide-angle beam scanning.

[0068] In some preferred embodiments, the characteristic impedance of the excitation port is set to 50 ohms; the narrow side width of the signal conductor in the waveguide transition structure is 1.2 mm, the wide side width is 4.2 mm, and the length is 5 mm, which helps to achieve a smooth impedance transition; the dielectric substrate H1 has dimensions of 151.45 × 14 × 0.508 mm³, and the dielectric substrate is made of Rogers RO4003C material with a dielectric constant of 3.55 and a loss tangent of 0.0027.

[0069] To verify the antenna performance, simulations were performed on this embodiment, and the results of its reflection coefficient and transmission coefficient are as follows: Figure 6 As shown in the figure. Simulation results show that the operating frequency band of the antenna array is 23-28.6 GHz. Within this frequency band, the reflection coefficient is less than -10 dB, indicating good antenna impedance matching and achieving efficient radiation; at the same time, the transmission coefficient is less than -12 dB, indicating that most of the input energy has been effectively radiated, further confirming that the antenna has excellent radiation efficiency. Figure 7 The simulation results of the millimeter-wave horizontally polarized omnidirectional antenna array in this embodiment are presented. Within the operating frequency band, its peak gain reaches 12 dBi, verifying that the antenna achieves high gain characteristics while providing omnidirectional coverage. Figure 8 and Figure 9 The radiation patterns of the antenna under excitation ports S1 and S2 are shown respectively. Simulation results show that in the H-plane, the antenna maintains stable omnidirectional radiation characteristics across the entire operating frequency band (23-28.6 GHz) with low non-circularity. In the E-plane, it exhibits significant frequency scanning characteristics: when excited by the first excitation port S1, the beam scans from 145° to 90°; when excited by the second excitation port S2, the beam scans from 35° to 90°. Together, they achieve wide-angle beam coverage in the E-plane from 35° to 145° (a total of 110°). In summary, this antenna achieves the key characteristics of stable omnidirectional radiation in the H-plane and wide-range beam scanning in the E-plane.

[0070] Comprehensive simulation results Figure 6 , Figure 7 , Figure 8 as well as Figure 9This invention proposes a novel wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna array. Utilizing a substrate-integrated waveguide slot array and a half-mode substrate-integrated waveguide, dual-mode (slot mode and substrate-integrated waveguide mode) operation is achieved. In the array elements, a pair of symmetrical "I"-shaped slots are equivalent to vertically placed magnetic dipoles, which is beneficial for achieving horizontally polarized omnidirectional radiation characteristics. Furthermore, the frequency scanning characteristics of the leaky wave mode are utilized to achieve a large-area beam scanning in the E-plane. In addition, by adjusting the width of the wide wall of the half-mode substrate-integrated waveguide, the non-circularity of the antenna radiation is reduced, thereby realizing a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna.

[0071] It should be noted that the core of this invention lies in the ingenious combination of the slot mode and the substrate integrated waveguide mode to achieve a horizontally polarized omnidirectional antenna. Simultaneously, the leaky wave mode is used to achieve beam scanning characteristics. The open-stopband problem is effectively suppressed by canceling out the inductance of the impedance-matched metallized via with the capacitance of the slot, thus realizing a wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna. The embodiments of this invention are only one implementation. By modifying its structure, such as using different transmission lines, modifying the slot shape, and optimizing the feed network, various forms of millimeter-wave horizontally polarized omnidirectional antennas can be realized. Therefore, the technical solution of this invention embodiment serves as an example to demonstrate the implementation of a millimeter-wave horizontally polarized omnidirectional antenna with wide-angle scanning.

[0072] The embodiments described in this invention are for the purpose of more clearly illustrating the technical solutions of the embodiments of this invention, and do not constitute a limitation on the technical solutions provided by the embodiments of this invention. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this invention are also applicable to similar technical problems.

[0073] Those skilled in the art will understand that the technical solutions illustrated in the figures do not constitute a limitation on the embodiments of the present invention. The terms "first," "second," "third," "fourth," etc. (if present) in the specification and the aforementioned figures are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0074] It should be understood that in this invention, "at least one (item)" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0075] The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of the present invention should be within the scope of the claims of the present invention.

Claims

1. A wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna, characterized in that, include: A dielectric substrate having a first excitation port and a second excitation port, as well as a first coaxial connector and a second coaxial connector at both ends; The substrate-integrated waveguide slot array includes a first row of "I"-shaped periodic slots disposed on a first slotted metal patch and a second row of "I"-shaped periodic slots disposed on a second slotted metal patch, and three rows of metallized vias; the three rows of metallized vias are disposed through the dielectric substrate, and their two ends are respectively connected to the first slotted metal patch and the second slotted metal patch. A half-mode substrate integrated waveguide includes a first slotted metal patch and a second slotted metal patch, as well as a second row of metallized vias; The first waveguide transition structure has its two ends connected to the first grounded coplanar waveguide and the first substrate integrated waveguide, respectively. The second waveguide transition structure has its two ends connected to the second grounded coplanar waveguide and the second substrate integrated waveguide, respectively. The first row of "I"-shaped periodic slots and the second row of "I"-shaped periodic slots are symmetrically distributed on both surfaces of the dielectric substrate, and together they are used to achieve horizontal polarization omnidirectional radiation of the antenna. The shapes of the first row of "I"-shaped periodic slots and the second row of "I"-shaped periodic slots can be changed to "1", "L" or "Z" shapes. The gain and scanning rate of the antenna can be controlled by adjusting the slot structure. The substrate integrated waveguide slot array further includes a first row of metallized vias, a second row of metallized vias, and a third row of impedance matching metallized vias disposed on the dielectric substrate; the first row of metallized vias and the second row of metallized vias control the leakage of radio frequency energy, and the antenna operating frequency band and radiation characteristics can be changed by adjusting the spacing between the two rows of metallized vias; the third row of impedance matching metallized vias and the periodic slots provide inductive and capacitive properties, respectively, to suppress the open stopband.

2. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 1, characterized in that, The first coaxial connector at the bottom and the second coaxial connector at the top of the dielectric substrate are used to realize a detachable, low-loss connection between the antenna and the transmission line. The first ground coplanar waveguide, the first waveguide transition structure, and the first substrate integrated waveguide, which are disposed above the first coaxial connector, are connected in sequence to achieve low-loss transmission of radio frequency signals and transmission mode adaptation; the second ground coplanar waveguide, the second waveguide transition structure, and the second substrate integrated waveguide, which are disposed below the second coaxial connector, are connected in sequence to achieve low-loss transmission of radio frequency signals and transmission mode adaptation.

3. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 1, characterized in that, The first grounded coplanar waveguide and the second grounded coplanar waveguide are distributed in mirror symmetry at both ends of the dielectric substrate. The first waveguide transition structure and the second waveguide transition structure are distributed in mirror symmetry at both ends of the dielectric substrate. The first substrate integrated waveguide and the second substrate integrated waveguide are distributed in mirror symmetry at both ends of the substrate integrated waveguide slot array.

4. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 1, characterized in that, It also includes a first slotted metal patch disposed on the left surface of the dielectric substrate and a second slotted metal patch disposed on the right surface; the first slotted metal patch has two symmetrically distributed gradient horn-shaped slots at its upper and lower ends, and a first row of "I"-shaped periodic slots in the middle for efficient radiation of radio frequency energy on the left surface; the second slotted metal patch has rectangular metal patches at its upper and lower ends, serving as the ground plane of the feed network, and a second row of "I"-shaped periodic slots in the middle for efficient radiation of radio frequency energy on the right surface.

5. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 1, characterized in that, The half-mode substrate integrated waveguide is disposed on the right side of the substrate integrated waveguide slot array and shares the second row of metallized vias with the substrate integrated waveguide slot array; the width of the wide wall of the half-mode substrate integrated waveguide can be adjusted to control the non-circularity of the antenna's omnidirectional radiation.

6. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 1, characterized in that, The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna includes a row of periodic array elements; the array elements consist of slotted substrate integrated waveguides and half-mode substrate integrated waveguides, including a pair of slots symmetrically etched on metal patches on both sides of the dielectric substrate and an impedance-matching metallized via.

7. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 6, characterized in that, The substrate integrated waveguide slot array consists of 19 array elements. Each array element has a period of 6.75 mm, a longitudinal slot length of 4 mm, a width of 0.2 mm, a transverse slot length of 1.2 mm, and a width of 0.2 mm. All metallized vias have a diameter of 0.5 mm and a via spacing of 0.75 mm. The spacing between the first row of metallized vias and the second row of metallized vias is 5 mm.

8. The wide-angle scanning millimeter-wave horizontally polarized omnidirectional antenna according to claim 1, characterized in that, The dielectric substrate is made of Rogers RO4003C material with a dielectric constant of 3.55, a loss tangent of 0.0027, and dimensions of 151.45×14×0.508 mm³. The antenna operates in the frequency band of 23-28.6 GHz, with a reflection coefficient of less than -10 dB, a transmission coefficient of less than -12 dB, and a peak gain of 12 dBi within this band. It maintains omnidirectional radiation and low non-circularity in the H-plane, and achieves a wide-angle beam scanning of 110° from 35° to 145° through the first excitation port and the second excitation port in the E-plane, respectively.

Images