Millimeter wave microwave co-boresight transparent antenna

Abstract

The application discloses a millimeter wave microwave co-aperture transparent antenna, belongs to the technical field of 5G wireless communication and antenna, is a coupled series-fed patch antenna, four high-frequency patch antennas are connected in series and coupled feeding is carried out, the same structure is used to realize dual-band operation, including a millimeter wave radar operating frequency band and a microwave communication frequency band, high directivity and high gain of a forward detection radar are realized; meanwhile, a gap is designed between the center two patches to form a capacitive coupling, and the directional diagram of the microwave frequency band is changed from end-fire to side-fire direction; the antenna is integrated on a high-transmittance dielectric substrate, and the antenna metal part is meshed in the micron scale. The application can realize co-aperture of the microwave frequency band communication antenna and the millimeter wave radar antenna; the structure is simple, the profile is low, the volume is small, the conformation is good, is suitable for integrated mobile terminal equipment of sensing and feeling integration; the efficiency and the transparency of the antenna are considered, a win-win of high-performance co-aperture antenna and transparent antenna is realized, and the application is suitable for being integrated on transparent materials such as glass.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of 5G wireless communication and antenna, and relates to a millimeter wave microwave co-aperture transparent antenna which can be used for communication and radar detection of a vehicle. BACKGROUND

[0002] With the continuous development of mobile communication technology, the communication rate is greatly improved, and Internet of Things and automatic driving are increasingly important in mobile communication. The automatic driving vehicle needs to integrate a forward detection radar antenna to realize obstacle and distance detection, and needs to communicate with surrounding terminals and base stations to update the communication network in real time, so that the user can make better path planning. The vehicle-mounted radar antenna often uses a millimeter wave antenna to achieve high detection accuracy, and the forward detection radar needs high directivity and long detection distance. The communication antenna selects a microwave frequency band to ensure a long communication distance and better omnidirectionality.

[0003] Most of the current antennas are designed separately for communication antennas and radar detection and sensing antennas, the communication antenna uses a fin antenna or a spiral line antenna, which is large in size and affects the overall appearance. The vehicle-mounted detection radar can only be placed inside the vehicle body shell, resulting in large antenna loss and affecting the performance of the antenna. In order to reduce the path loss and obtain a long radar detection distance, the radar antenna can be integrated on the vehicle window, and the antenna needs to be highly transparent at this time. At the same time, the millimeter wave antenna and the microwave antenna can be designed integrally to reduce the size of the antenna. Therefore, how to design a small and highly transparent communication and radar sensing integrated antenna has great significance. SUMMARY

[0004] The application is designed to solve the problems of large size, high profile, and large millimeter wave radar antenna loss in the design of multiple antennas in the vehicle-mounted antenna, and a millimeter wave antenna and a microwave antenna co-aperture planar transparent patch antenna applied to the vehicle window is designed, the microwave and millimeter wave antennas complete co-aperture design, can realize more than 75% transparency, and can be installed on the vehicle window.

[0005] In order to achieve the above purpose, the technical scheme adopted by the application is:

[0006] The application discloses a millimeter wave microwave co-aperture transparent antenna, which is a coupled series-fed patch antenna.

[0007] The application discloses a millimeter wave microwave co-aperture transparent antenna, which comprises a dielectric substrate 1, an antenna radiator 2 made of metal and a metal ground plate 3. Figure 1 The antenna radiator 2 and the metal ground plate 3 are tightly attached to upper and lower surfaces of the dielectric substrate 1 respectively, as shown in the figure.

[0008] The antenna radiator 2 comprises four antenna radiating units 201-204 made of metal, a capacitive coupling feeding structure 205, a low-frequency antenna impedance transformer 207 and a feeding microstrip line 208. The four antenna radiating units are connected through a series feeding line 206 to form a 1x4 antenna array, and the four antenna radiating units and the feeding line 206 work as a whole at a microwave frequency band. The fourth antenna radiating unit 204 is connected to the feeding microstrip line 208 through the low-frequency antenna impedance transformer 207 for further matching of an impedance value at the microwave frequency band. The capacitive coupling feeding structure 205 is arranged between the second antenna radiating unit 202 and the third antenna radiating unit 203 for forming a capacitive coupling connection, adjusting a current direction and keeping consistency of the current direction of the four patches at the microwave frequency band.

[0009] The metal parts of the antenna radiating units 201-204 are gridded. The metal ground plate 3 is designed in a grid form. The grid size of the metal ground plate 3 is not required to be equal to or different from the grid size of the antenna radiating units 201-204, and can be adjusted according to the transparency requirement.

[0010] Further, the four antenna radiating units 201-204 can be square patches or patches of any shape and work at a millimeter wave frequency band. The sizes of the antenna radiating units 201-204 can be completely consistent or similar to realize high gain of the array.

[0011] Further, the capacitive coupling feeding structure 205 is a gap structure designed in the middle of the feeding line 206 between the second antenna radiation unit 202 and the third antenna radiation unit 203, which can be diversified, such as T-shaped gap, zigzag-shaped gap, and irregular shapes, so as to better conduct induced current to the antenna radiation units 201 and 202, and make the current amplitude of the four antenna radiation units similar. The design principle is that the four patches and the feeding line work as a whole in the microwave frequency band. However, the four patches directly in series feeding will form a reverse current, resulting in a zero point in the edge-shooting direction, and poor directivity. Therefore, the capacitive coupling gap 205 is arranged between the second patch 202 and the third patch 203 to form a capacitive coupling connection, adjust the current direction, keep the consistency of the current direction of the four patches in the microwave frequency band, form an edge-shooting pattern, and at the same time, do not affect the pattern of the millimeter wave band antenna. The capacitive coupling gap form can be diversified, including T-shaped, zigzag-shaped, and the like.

[0012] Further, in order to further match the impedance value when working in the microwave frequency band, an impedance transformer 207 is used to connect the antenna and the microstrip line. The low-frequency working frequency of the microwave frequency band can be adjusted by the length, width and distance between the patch antenna units 201.

[0013] Further, the material of the dielectric substrate 1 is transparent, and the dielectric constant is 3-4, such as PET, quartz glass, etc.

[0014] Further, the metal part of the antenna radiation units 201-204 is gridded, and the grid size is 50-200 μm, which can be selected according to the transparency requirement. Specifically, as follows:

[0015] To Figure 1 The metal part of the millimeter wave microwave co-caliber antenna is gridded, as shown in Figure 2 , Figure 3 The size of the metal grid determines the equivalent conductivity and transparency of the metal plane. A larger grid size results in higher transparency, but lower conductivity, which affects the antenna efficiency. The gridding process is as follows: first, coat photoresist on the high-transparency dielectric substrate 1, and under the action of ultraviolet lithography, the metal grid pattern in the photo mask is transferred to the photoresist; then, deposit metal on the dielectric through a magnetron sputtering device; finally, clean the excess photoresist and metal by acetone, and complete the stripping of the excess metal, to obtain the gridded antenna radiation units 201-204.

[0016] Figure 2 A structure magnification diagram of the antenna radiator after gridding the metal in the application is shown. 401 is the gridded metal wire, and 402 is the gap after gridding.Figure 3 A structure magnification view after the floor metal gridding in the application is shown, 403 is the gridding metal wire, 404 is the gap after gridding. Two adopt different size square metal grid, give attention to efficiency and reliability, the size of the grid of the antenna radiator and the floor has no strict relation, can the grid of the antenna radiator be larger, can the floor grid be larger, or both are equal. But the grid openwork way is not limited to square, can use rectangle, circle, triangle or hexagon etc. according to demand and technology.

[0017] The application of a millimeter wave microwave common-aperture transparent antenna can be placed on the vehicle glass without affecting the driver's view and reducing the loss of the antenna performance caused by the vehicle shell.

[0018] The working process of the application: the radio frequency signal feeds the patch antenna radiation unit through the microstrip line 208. The metal of the patch antenna radiation unit 2 and the metal floor 3 is composed of gridding transparent metal wire. The antenna dielectric substrate 1 adopts transparent substrate, such as PET, quartz glass, etc. When working in the microwave frequency band, the radio frequency signal reaches the patch antenna radiation unit through the impedance transformer 207, the patch antenna radiation unit 203, 204 is a group of radiators for low frequency signal radiation, and the current is coupled to the antenna radiation unit 201, 202 through the capacitive coupling feed slot 205, to obtain the surface current close to the same direction as 203, 204, to form a broadside radiation pattern, the beam width is wide, covering the communication frequency band. When working in the millimeter wave frequency band, the radio frequency signal reaches each patch antenna radiation unit (201-204) through the series feed line, and forms a half wavelength resonance on the side of each antenna radiation unit. The four antenna radiation units form an array in the broadside direction to form superposition, realize high gain and high directivity millimeter wave radar antenna.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] (1) The millimeter wave microwave common-aperture transparent antenna realizes the common-aperture of the microwave frequency band communication antenna and the millimeter wave band radar antenna, and has simple structure, low profile, small volume, good conformability, and is suitable for integrated mobile terminal equipment.

[0021] (2) The millimeter wave microwave common-aperture transparent antenna adopts two different metal grids to transparently design the patch and the floor metal, which takes into account the efficiency and transparency of the antenna, realizes the win-win of high-performance common-aperture antenna and transparent antenna, and is suitable for integration on glass and other transparent materials.

[0022] (3) The millimeter wave microwave common-aperture transparent antenna adopts series feed through slot coupling to realize the broadside pattern in the microwave frequency band. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic diagram of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0024] Figure 2 is a schematic diagram of a millimeter wave microwave co-aperture transparent antenna grid radiation structure according to the present application;

[0025] Figure 3 is a schematic diagram of a millimeter wave microwave co-aperture transparent antenna grid floor structure according to the present application;

[0026] Figure 4 is a microwave band S parameter of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0027] Figure 5 is a millimeter wave band S parameter of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0028] Figure 6 is a microwave band current distribution of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0029] Figure 7 is a millimeter wave band current distribution of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0030] Figure 8 is a microwave band two-dimensional radiation pattern of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0031] Figure 9 is a millimeter wave band two-dimensional radiation pattern of a millimeter wave microwave co-aperture transparent antenna according to the present application;

[0032] In the figure: 1 is a dielectric substrate, 2 is an antenna radiator as a whole, 201-204 are antenna radiation units, 205 is a capacitive coupling feed structure, 206 is a series feed line, 207 is a low-frequency antenna impedance transformer, 208 is a feed microstrip line, 3 is a metal floor, 401 is a metal grid after the antenna radiator is gridized, 402 is a hollow gap after the antenna radiator is gridized, 403 is a metal grid after the floor is gridized, 404 is a hollow gap after the floor is gridized. DETAILED DESCRIPTION

[0033] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings and technical solutions.

[0034] Reference Figure 1The millimeter-wave microwave common-aperture transparent antenna comprises three parts: a dielectric substrate 1, a radiator 2, and a metal ground plane 3. The antenna radiator 2 includes patch antenna elements 201-204, a capacitively coupled feed structure 205, a series feed line 206, a low-frequency antenna impedance transformer 207, and a feed microstrip line 208. The radiator 2 is placed on the upper surface of the dielectric substrate 1, and the metal ground plane 3 is placed on the lower surface of the dielectric substrate 1.

[0035] The overall dimensions of the millimeter-wave microwave common-aperture transparent antenna described in this embodiment are approximately 38 × 16 × 1 mm. 3 Antenna elements 201-204 are all 3.0mm long. To match the impedance, antenna elements 202 and 203 are 4.3mm wide, and antenna elements 201 and 204 are 4.1mm wide. The center distance between adjacent antenna elements is 5.75mm. The string feed 206 is 0.95mm wide, and the impedance transformer is 1.0mm wide and 6.5mm long. The branch length of the zigzag coupled feed structure 205 is 0.8mm, and the slot width is 0.1mm. PET dielectric is used, with a relative permittivity of 3.7, a loss tangent of 0.00031, and a thickness of 1mm.

[0036] like Figure 2 , Figure 3 As shown, the metal portion of the millimeter-wave microwave common-aperture transparent antenna is metal meshed. In this embodiment, the width of the metal 401 in the metal mesh of the antenna radiator is 10 μm, the size of the mesh cutout 402 is 150 μm, and the equivalent conductivity is 1.0 × 10⁻⁶. 6 S / m. Achieving 86% transparency in a single layer. The floor uses a 10μm wide grid of 403 metal with 180μm 404 mesh openings, resulting in an equivalent conductivity of 7.1×10⁻⁶. 5 S / m. Achieves 89% transparency in a single layer. Overall. Figure 2 , Figure 3 The antenna transparency can reach over 75%.

[0037] Figure 4 The figure shows the S-parameter curve of the present invention when it operates in the microwave frequency band. As can be seen from the figure, the -10dB operating frequency band range is 5852-5945MHz, which can cover the microwave operating frequency band of automotive communication antennas.

[0038] Figure 5 The figure shows the S-parameter curve of the present invention when it operates in the millimeter-wave band. As can be seen from the figure, the -10dB operating frequency range is 24.25-29.78GHz, which can cover the millimeter-wave frequency band of automotive forward detection radar.

[0039] Figure 6is the current distribution of the application at the microwave frequency of 5.88GHz. Through the coupling effect of the several-shaped coupling feed slot 205, the surface currents with similar size and same direction are induced on the antenna units 201 and 202, which together form the edge-on radiation pattern.

[0040] Figure 7 is the current distribution of the application at the millimeter wave frequency of 25.4GHz. The antenna units 201-204 work at this frequency band separately, and form a half-wavelength resonance on the side of each antenna unit, and the phase of the current is consistent, realizing high gain and high directivity of the array.

[0041] Figure 8 is the E-plane and H-plane radiation pattern of the application at the microwave frequency of 5.88GHz. The E-plane pattern is tilted to a certain extent, which can adapt to the tilt angle of the windshield of the car. The maximum gain is 2.19dB, the 3dB beam width of the E-plane is 60.0°, and the 3dB beam width of the H-plane is 120.4°.

[0042] Figure 9 is the E-plane and H-plane radiation pattern of the application at the millimeter wave frequency of 25.4GHz. The maximum radiation direction is upward edge-on. The maximum gain is 10.7dB, and the 3dB beam width is 17.7°.

[0043] The above-described embodiments only express the implementation of the application, but cannot be interpreted as a limitation on the scope of the patent of the application. It should be pointed out that for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are all within the protection scope of the application.

Claims

1. A millimeter-wave microwave common-aperture transparent antenna, characterized in that, The antenna described is a coupled series-fed patch antenna. It consists of four high-frequency patch antennas connected in series and coupled for feeding via a microstrip line. Using the same structure, it achieves dual-band operation, including the millimeter-wave radar operating band and the microwave communication band. This enables high directivity and high gain for forward-looking radar, while simultaneously achieving high gain for the millimeter-wave antenna and a wide beam for the microwave antenna. Furthermore, a gap is designed between the two central patches to form capacitive coupling, changing the radiation pattern of the microwave band from end-firing to side-firing. The antenna is integrated onto a high-transmittance dielectric substrate, and the metal portion of the antenna is meshed on a micrometer scale. The transparent antenna includes a dielectric substrate (1), a metal antenna radiator (2), and a metal ground plane (3), with the antenna radiator (2) and the metal ground plane (3) respectively attached to the upper and lower surfaces of the dielectric substrate (1). The antenna radiator (2) includes four metal antenna radiating elements (201)-(204), a capacitively coupled feed structure (205), a low-frequency antenna impedance transformer (207), and a feed microstrip line (208). The four antenna radiating elements are all patch structures and are connected by a series feed line (206) to form a 1×4 antenna array, which operates as a whole in the microwave frequency band. The fourth antenna radiating element (204) is connected to the feed microstrip line (208) through a low-frequency antenna impedance transformer (207) to further match the impedance value when operating in the microwave band; the capacitively coupled feed structure (205) is a slot structure, arranged between the second antenna radiating element (202) and the third antenna radiating element (203), used to form a capacitively coupled connection, adjust the current direction, maintain the consistency of the current direction of the four patches in the microwave band, form a side-firing pattern, and at the same time not affect the pattern of the millimeter-wave band antenna; The metal parts of the antenna radiating units (201)-(204) are gridded; the metal floor (3) is designed with a grid.

2. The millimeter-wave microwave common-aperture transparent antenna according to claim 1, characterized in that, The four antenna radiating elements (201)-(204) are square patches or patches of any shape, and their specific dimensions are determined by the operating frequency.

3. The millimeter-wave microwave common-aperture transparent antenna according to claim 1, characterized in that, The gap structure includes T-shaped gaps, zigzag gaps, zigzag gaps, or other irregular shapes.

4. The millimeter-wave microwave common-aperture transparent antenna according to claim 1, characterized in that, The dielectric substrate (1) is made of a transparent material with a dielectric constant of 3 to 4.

5. A millimeter-wave microwave common-aperture transparent antenna according to claim 1, characterized in that... The metal parts of the antenna radiating elements (201)-(204) are meshed, and different sizes are selected according to the transparency requirements.

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