Microwave / millimeter wave dual-band wideband antenna of patch and transmission array structure multiplexing

Abstract

The application provides a microwave / millimeter wave dual-frequency broadband antenna with structure multiplexing of a patch and a transmission array, which comprises a metal plate, a microwave power divider, an L-shaped probe, a polarization rotation surface and a transmission array surface, the microwave frequency band of the antenna is fed by a coaxial connector, and the millimeter wave frequency band is fed by a waveguide; one end of the L-shaped probe is connected with the output end of the microwave power divider, and the other end is suspended; the transmission array surface is located above the polarization rotation surface, and the transmission array surface comprises a plurality of array units, each array unit comprises a first PCB plate, a second PCB plate, a third PCB plate and a fourth PCB plate, metal layers are arranged on both sides of each PCB plate, and patches, U-shaped grooves and phase shift lines are arranged on the corresponding metal layers. The application has the advantages of high structure multiplexing rate, small size, wide bandwidth, simple millimeter wave frequency band feeding, low feeding loss, high gain and the like.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure. Background Technology

[0002] In recent years, with the continuous development of millimeter-wave communication, the coexistence of microwave and millimeter-wave antennas in antenna systems has attracted increasing attention, posing significant challenges to antenna design. The main issues include: 1) Due to the high attenuation of millimeter-wave electromagnetic waves in the atmosphere, antennas in this band generally need to be arrayed to compensate for propagation loss through high gain. However, since antenna arrays often require a feeding network to power each element, traditional antenna arrays may result in high feeding losses; 2) In the coexistence of microwave and millimeter-wave antennas, the number of antennas in the communication system increases. Simply placing antennas from both bands together leads to a larger overall antenna system size, hindering miniaturization; 3) Microwave and millimeter-wave coexistence essentially achieves the function of a dual-band antenna, but due to the high frequency ratio of these two bands, traditional dual-band antenna techniques, such as multi-mode methods, are no longer applicable. Therefore, in summary, how to organically combine microwave and millimeter-wave antennas while simultaneously achieving miniaturization and high gain in the millimeter-wave band is a problem worthy of further research.

[0003] Currently, the schemes for realizing microwave and millimeter-wave dual-band antennas can be roughly divided into two categories: one is to use two independent radiation structures for the two frequency bands. For example, in reference [1], a monopole antenna is used for the microwave band and a grid array antenna is used for the millimeter-wave band; in reference [2], a monopole antenna is used for the microwave band and a patch slot antenna is used for the millimeter-wave band. This scheme provides a relatively intuitive design idea for realizing microwave and millimeter-wave dual-band antennas, but the separate placement of the radiation structure will increase the size of the antenna system to a certain extent. The other is to combine microwave and millimeter-wave antennas in a common aperture manner. For example, reference [3] combines a substrate integrated waveguide leaky wave antenna and a PIFA antenna, in which the substrate integrated waveguide of the millimeter-wave band constitutes part of the structure of the PIFA antenna of the microwave band, and the two antennas share the same aperture surface. Reference [4] combines a patch antenna and a magnetoelectric dipole antenna, and the two share the same aperture surface by overlapping placement. In comparison, the co-aperture scheme is currently the better dual-band solution for microwave and millimeter waves. It can effectively reduce the physical size of the antenna system. However, the reported schemes usually use direct-fed arrays in the millimeter wave band, which requires the introduction of a feeding network. This may bring some feeding loss. On the other hand, in the case of co-aperture, antennas operating in the microwave and millimeter wave bands usually adopt a structure reuse approach. However, the structure reuse rate in the reported designs is low, which will directly affect the size of the antenna.

[0004] [1] L.Zhang, KYSee, B.Zhang and YPZhang, "Integration of dual-bandmonopole and microstrip grid array for single-chip tri-band application," IEEETrans.Antennas Propag., vol.61, no.1, pp.439-443, Jan.2013.

[0005] [2] D.Wang and CHChan, "Multiband antenna for Wi-Fi and Wi-Gigcommunications," IEEE Antennas Wireless Propag. Lett., vol.15, pp.309-312, 2016.

[0006] [3]YRDing and YJCheng, "A Tri-Band Shared-Aperture Antenna for (2.4,5.2)GHz Wi-Fi Application With MIMO Function and 60GHz Wi-GigApplication With Beam-Scanning Function," IEEE Transactions on Antennas andPropagation, vol.68, no.3, pp.1973-1981, March 2020

[0007] [4]X.Yang et al., "An Integrated Tri-Band Antenna System With LargeFrequency Ratio for WLAN and WiGig Applications," IEEE Transactions on Industrial Electronics, vol.68, no.5, pp. Summary of the Invention

[0008] To address at least one of the problems existing in the prior art, this invention proposes a microwave / millimeter-wave dual-band broadband antenna that reuses a patch and a transmission array structure. This antenna operates as a patch antenna in the microwave band and a transmission array antenna in the millimeter-wave band, with both antennas designed within the same aperture plane using a reused structure. Compared to traditional microwave / millimeter-wave dual-band antennas, this invention offers advantages such as high structural reuse rate, small size, wide bandwidth, simple millimeter-wave band feeding, low feeding loss, and high gain.

[0009] To achieve the purpose of this invention, this invention provides a microwave / millimeter-wave dual-band broadband antenna that combines patch and transmission array structure, including a metal plate, a microwave power divider, an L-shaped probe, a polarization rotating surface and a transmission array surface. The microwave band of the antenna is fed by a coaxial connector, and the millimeter-wave band is fed by a waveguide.

[0010] Two L-shaped probes are provided and placed mirror images of each other about the YOZ plane. One end of each L-shaped probe is connected to the corresponding output terminal of the microwave power divider, and the other end is left floating.

[0011] The transmission array is located above the polarization rotating surface. The transmission array includes multiple array elements. Each array element includes a first PCB board, a second PCB board, a third PCB board, and a fourth PCB board. Each PCB board has metal layers on both sides, defined as a first metal layer, a second metal layer, a third metal layer, a fourth metal layer, and a fifth metal layer. A first circular patch is provided on the first metal layer, a first U-shaped groove is provided on the second metal layer, a phase-shifting line is provided on the third metal layer, a second U-shaped groove is provided on the fourth metal layer, and a second circular patch is provided on the fifth metal layer. The first U-shaped groove and the second U-shaped groove are orthogonal.

[0012] Furthermore, it also includes a dielectric support, which is fixed on a metal plate, and the transmission array surface is fixed on the dielectric support and located above the polarization rotating surface.

[0013] Furthermore, the polarized rotating surface includes multiple arrayed reflective elements.

[0014] Furthermore, each reflective unit includes a floor and a patch located above the floor. The reflective unit is used to reflect electromagnetic waves while rotating the polarization direction of the electromagnetic waves.

[0015] Furthermore, the microwave power divider and the polarization rotating surface are placed back-to-back on both sides of the metal plate, that is, the floor side of the microwave power divider and the polarization rotating surface is attached to the metal plate.

[0016] Furthermore, the first U-shaped groove and the second U-shaped groove have the same dimensions.

[0017] Furthermore, the first circular patch and the second circular patch are the same size.

[0018] Furthermore, the length of the phase shift line is determined by the required phase shift magnitude for each array element, and the phase shift magnitude of the phase shift line is...

[0019]

[0020] Where x and y represent the coordinates of a point on the transmission array surface in the x and y directions, f represents the focal length of the transmission array surface, and λ represents the free-space wavelength at the center frequency of the millimeter-wave band. Indicates any initial phase; This represents the required phase shift at point (x, y).

[0021] Furthermore, the phase shift lines of each array element are of different lengths.

[0022] Furthermore, the microwave power divider is a microstrip power divider that splits one signal into two, with a phase difference of 180 degrees between the two output signals.

[0023] Compared with the prior art, the present invention can achieve at least the following beneficial effects:

[0024] (1) This invention proposes a microwave / millimeter-wave dual-band broadband antenna that reuses a patch and a transmission array structure. This antenna operates as a patch antenna in the microwave band and a transmission array antenna in the millimeter-wave band, with both antennas designed in the same aperture plane using a reused structure. Compared with traditional microwave / millimeter-wave dual-band antennas, this invention has advantages such as high structural reuse rate, small size, wide bandwidth, simple millimeter-wave band feeding, low feeding loss, and high gain.

[0025] (2) This invention proposes a microwave / millimeter-wave dual-band broadband antenna that reuses a patch and a transmission array structure. The microwave band is 2.4 GHz, and the millimeter-wave band is 60 GHz. This antenna can be used for Wi-Fi / Wi-Gig applications. Research has found that the transmission array surface in this antenna can be equivalent to a metal patch. Therefore, the radiation structures of the microwave and millimeter-wave bands can be organically combined and share the same radiation aperture through structural reuse. Specifically, in the microwave band, the antenna operates as a patch antenna, while in the millimeter-wave band, it operates as a transmission array. Since the transmission array antenna itself uses a space-fed feeding method and naturally possesses high gain characteristics, this invention has the advantages of simple feeding, low feeding loss, and high gain in the millimeter-wave band. Furthermore, due to the reuse of the array surface and the patch, the reuse rate of the microwave and millimeter-wave band radiation structures in this invention can reach 100%, thus possessing the advantages of high structural reuse rate and small size. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structures, as provided in an embodiment of the present invention.

[0027] Figure 2 This is a top view of a microwave / millimeter-wave dual-band broadband antenna that combines patch and transmission array structure according to an embodiment of the present invention.

[0028] Figure 3 This is a side view of a microwave / millimeter-wave dual-band broadband antenna that combines patch and transmission array structure according to an embodiment of the present invention.

[0029] Figure 4 This is an exploded view of the array surface in an embodiment of the present invention.

[0030] Figure 5 This is an exploded view of the array element in an embodiment of the present invention.

[0031] Figure 6 This is a top view of the polarized rotating surface in an embodiment of the present invention.

[0032] Figure 7 This is a schematic diagram of the structure of the reflection unit in an embodiment of the present invention.

[0033] Figure 8 This is a top view of the microwave power divider in an embodiment of the present invention.

[0034] Figure 9 This is a top view of the metal plate in an embodiment of the present invention.

[0035] Figure 10 This is a schematic diagram of the reflection coefficient of the antenna in the microwave band in an embodiment of the present invention.

[0036] Figure 11 This is the radiation pattern of the antenna in the E-plane and H-plane at the center frequency of the microwave band in the embodiment of the present invention.

[0037] Figure 12 This is a schematic diagram of the gain characteristics of the antenna in the microwave band in an embodiment of the present invention.

[0038] Figure 13 This is a schematic diagram of the reflection coefficient of the antenna in the millimeter-wave band in an embodiment of the present invention.

[0039] Figure 14 This is a schematic diagram of the gain characteristics of the antenna in the millimeter-wave band in an embodiment of the present invention.

[0040] Figure 15 This is the radiation pattern of the antenna in the E-plane and H-plane at the center frequency of the millimeter-wave band in the embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] This invention proposes a microwave / millimeter-wave dual-band broadband antenna that combines patch and transmission array structures. Figures 1 to 3 The images show a full view, a top view, and a side view of the antenna structure. The antenna includes a polarization rotating surface 11, a transmission array 12, an L-shaped probe 13 for microwave band feeding, a microwave power divider 14, and a metal plate 33. The microwave band of the antenna is fed by a coaxial connector 21, and the millimeter-wave band is fed by a WR-14 standard waveguide 32.

[0043] There are two L-shaped probes 13, which are placed symmetrically in mirror about the YOZ plane. One end of the L-shaped probe 13 is electrically connected to the two output terminals of the microwave power divider 14, and the other end is suspended.

[0044] In some embodiments of the present invention, a plurality of second screw holes 22 are provided at the periphery of the microwave power divider 14, the metal plate 33 and the polarization rotating surface 11, for fixing the microwave power divider 14, the metal plate 33 and the polarization rotating surface 11, and for fixing them to the dielectric support 31.

[0045] In some embodiments of the present invention, a plurality of first screw holes 23 are provided at the periphery of the transmission array 12, and the transmission array 12 is fixed to the dielectric support 31 through the first screw holes 23. The transmission array 12 is located above the polarization rotating surface 11.

[0046] Figure 4 The diagram shows an exploded view of the transmission array 12, which includes a first PCB board 421, a second PCB board 422, a third PCB board 423, and a fourth PCB board 424, each with a metal layer. In some embodiments of the present invention, all four PCB boards are Rogers 5880 substrate with a relative permittivity of 2.2 and a loss tangent of 0.0009. The thicknesses of the first to fourth PCB boards are 0.254 mm, 0.127 mm, 0.127 mm, and 0.254 mm, respectively. The metal layers on the PCB boards are a first metal layer 411, a second metal layer 412, a third metal layer 413, a fourth metal layer 414, and a fifth metal layer 415. In some embodiments of the present invention, the entire transmission array 12 includes 324 array elements 24 arranged in an 18×18 configuration. Figure 5 The diagram shows an exploded view of an array element 24. A first circular patch 51 is etched on the first metal layer 411; a first U-shaped groove 52 is etched on the second metal layer 412; a phase-shifting line 53 is etched on the third metal layer 413; a second U-shaped groove 54 is etched on the fourth metal layer 414; and a second circular patch 55 is etched on the fifth metal layer 415. The first U-shaped groove 52 and the second U-shaped groove 54 are orthogonal to each other and have the same size. The first circular patch 51 and the second circular patch 55 have the same size. The length of the phase-shifting line 53 is determined by the required phase shift value for each element, and the specific phase shift value follows Fermat's principle.

[0047]

[0048] Where x and y represent the coordinates of a point on the transmission array surface 12 in the x and y directions, f represents the focal length of the transmission array surface 12, and λ represents the free-space wavelength at the center frequency of the millimeter-wave band. Indicates any initial phase; This indicates the required phase shift at point (x, y). The length of the phase shift line 53 varies in each array element 24.

[0049] Figure 6 The diagram shows a top view of the polarized rotating surface 11. In some embodiments of the invention, this surface is a single-layer PCB structure using Rogers 5880 board material with a thickness of 0.381 mm. This layer includes 2025 reflective units 61 arranged in a 45×45 configuration. Figure 7 As shown, each reflective unit 61 includes a floor and a spindle-shaped patch 71 located above the floor. All spindle-shaped patches 71 have the same structure and size. The spindle-shaped patch is used to reflect electromagnetic waves and rotate the polarization direction of the electromagnetic waves.

[0050] Figure 8 The diagram shows a top view of the microwave power divider 14, which is a single-layer PCB structure. In some embodiments of the present invention, Rogers 5880 board material with a thickness of 0.787 mm is used. The microwave power divider 14 is a microstrip power divider that splits a signal into two channels, with a phase difference of 180 degrees between the two output signals, forming a differential microwave feed.

[0051] Figure 9 The diagram shows the structure of the metal plate 33. This plate is mainly used to fix the standard waveguide 32 and to provide support for the PCB board of the polarization rotating surface 11 and the microwave power divider 14. The metal plate 33 has corresponding screw holes for fixing, and the metal plate 33 is located between the two PCB boards of the polarization rotating surface 11 and the microwave power divider 14. The polarization rotating surface 11 and the microwave power divider 14 are placed on both sides of the metal plate 33 in a "back-to-back" manner, that is, the ground side of the microwave power divider 14 and the polarization rotating surface 11 is in contact with the metal plate 33.

[0052] In terms of operating principle, this antenna can operate simultaneously in both microwave and millimeter-wave frequency bands. In the millimeter-wave mode, the transmission array 12 and the polarization rotating surface 11 form a folded transmission array, where the transmission array 12 is a transmit / receive unit type transmission array. The electromagnetic wave is emitted by the waveguide 32 and is an x-polarized linearly polarized wave. When the electromagnetic wave irradiates the transmission array 12, since the receiving unit composed of the first circular patch 51 in each array element 24 is y-polarized, the initial irradiation of the electromagnetic wave is reflected by the transmission array 12 to the polarization rotating surface 11. Subsequently, after being reflected again by the polarization rotating surface 11, the electromagnetic wave changes from x-polarization to y-polarization and irradiates the transmission array 12 again. At this time, the electromagnetic wave is received by the receiving unit in the array element 24, the phase is adjusted by the phase shifter 53, and finally radiated into the atmosphere by the transmitting unit composed of the second circular patch 55. Because the phase-shifting lines in each array element 24 have different lengths, different phase modulations can be applied to the incident electromagnetic wave. Furthermore, since the phase shift magnitude of each element follows Fermat's principle, the transmission array 12 can convert the incident spherical wave into an outgoing plane wave, thereby achieving a focused beam and high gain. The two electromagnetic wave reflection processes described above can be considered as folding the profile height of a traditional transmission array antenna. Therefore, the profile height of the transmission array antenna in this invention is approximately one-third of its unfolded height, while the focal length is the same as that of a traditional transmission array. Since the working principle of this invention is the same as that of a patch antenna in the microwave band, the profile height is a fixed value, meaning the distance between the transmission array 12 and the feed is fixed. This folding method allows the transmission array antenna to have a suitable focal length-to-diameter ratio with a fixed profile height.

[0053] When the antenna operates in the microwave band, the transmission array surface 12 can be equivalent to a metal patch, which is fed by a pair of differentially excited L-shaped probes 13, and its working principle is the same as that of a traditional patch antenna. The reason why the transmission array surface 12 can be equivalent to a metal patch is that since the size of the array element 24 is about 0.5 times the wavelength of the millimeter-wave band, after converting this size to the microwave band, the circular patches, slots, phase shift lines and other structures in the array element 24 are all smaller than one-tenth of the microwave band wavelength. Therefore, in the microwave band, these structures in the array surface 24 can be regarded as polarimetric small structures, so they will not affect the operation of the microwave band. At the same time, the large area of ​​metal in the transmission array surface 12, that is, the metal ground plane between the transmitting and receiving units, can be regarded as a whole metal sheet, and thus operate in the form of a metal patch in the microwave band.

[0054] Regarding antenna performance, Figures 10 to 12 The figure shows the antenna's performance parameters in the microwave band. Figure 10The impedance matching performance is shown. The antenna has a reflection coefficient of less than -10dB in the range of 2.04GHz to 2.63GHz and an impedance bandwidth of 26%, indicating that the antenna has broadband characteristics in the microwave band. Figure 11 The image shows the radiation patterns of the antenna in the E-plane and H-plane at the center frequency. The front-to-back ratio of both the E-plane and H-plane radiation patterns is greater than 18 dB, indicating that the antenna has good directivity in the microwave band. Figure 12 The antenna's gain characteristic curve is shown. Within the impedance bandwidth range of 2.04 GHz to 2.63 GHz, the peak gain is 9 dBi, and the gain fluctuation is less than ±1 dB.

[0055] Figures 13 to 15 The figure shows the antenna's performance parameters in the millimeter-wave band. Figure 13 The image shows the reflection coefficient of the antenna. The reflection coefficient of this antenna is less than -10dB in the 52GHz to 68GHz frequency band. Figure 14 The image shows the antenna's gain characteristic curve. The antenna has a peak gain of 25 dBi and a 3-dB gain bandwidth of 21%, indicating that it possesses high gain and wide bandwidth characteristics. At the center frequency, the E-plane and H-plane radiation patterns of the antenna are shown below. Figure 15 As shown, the sidelobes of the antenna in both the E and H planes are below -15dB, indicating good performance.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structures, characterized in that, The antenna includes a metal plate (33), a microwave power divider (14), an L-shaped probe (13), a polarization rotating surface (11), and a transmission array (12). The microwave band of the antenna is fed by a coaxial connector (21), and the millimeter-wave band is fed by a waveguide (32). Two L-shaped probes (13) are provided and placed in a mirror image with respect to the YOZ plane. One end of each L-shaped probe (13) is connected to the corresponding output terminal of the microwave power divider (14), and the other end is left suspended. The transmission array (12) is located above the polarization rotating surface (11). The transmission array (12) includes multiple array elements (24). Each array element (24) includes a first PCB board (421), a second PCB board (422), a third PCB board (423), and a fourth PCB board (424). Each PCB board has metal layers on both sides, defined as a first metal layer (411), a second metal layer (412), a third metal layer (413), and a fourth metal layer (424). The metal layer (414) and the fifth metal layer (415) are provided with a first circular patch (51) on the first metal layer (411), a first U-shaped groove (52) on the second metal layer (412), a phase shift line (53) on the third metal layer (413), a second U-shaped groove (54) on the fourth metal layer (414), and a second circular patch (55) on the fifth metal layer (415), and the first U-shaped groove (52) and the second U-shaped groove (54) are orthogonal.

2. The microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, It also includes a dielectric support (31), which is fixed on a metal plate (33), and a transmission array (12) is fixed on the dielectric support (31) and located above the polarization rotating surface (11).

3. The microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, The polarized rotating surface (11) includes multiple arrayed reflective elements (61).

4. The microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 3, characterized in that, Each reflective unit (61) includes a floor and a patch (71) located above the floor. The reflective unit (61) is used to reflect electromagnetic waves while rotating the polarization direction of the electromagnetic waves.

5. The microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, The microwave power divider (14) and the polarization rotating surface (11) are placed on both sides of the metal plate (33) in a "back-to-back" manner.

6. The microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, The first U-shaped groove (52) and the second U-shaped groove (54) have the same dimensions.

7. A microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, The first circular patch (51) and the second circular patch (55) are the same size.

8. The microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, The length of the phase shift line (53) is determined by the required phase shift size for each array element (24), and the phase shift size of the phase shift line (53) is... Where x and y represent the coordinates of a point on the transmission array surface (12) in the x and y directions, f represents the focal length of the transmission array surface (12), and λ represents the free space wavelength at the center frequency of the millimeter wave band. Indicates any initial phase; This represents the required phase shift at point (x, y).

9. A microwave / millimeter-wave dual-frequency broadband antenna that combines patch and transmission array structure according to claim 1, characterized in that, The phase shift line (53) of each array element (24) has a different length.

10. A microwave / millimeter-wave dual-band broadband antenna that combines patch and transmission array structure according to any one of claims 1-9, characterized in that, The microwave power divider (14) is a microstrip power divider that splits one signal into two, with a phase difference of 180 degrees between the two output signals.

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