A millimeter-wave array antenna with characteristics of high gain and low sidelobe level

Abstract

A millimeter-wave array antenna with high-gain and low sidelobe level characteristics, comprising a GCPW feeding structure, a one-to-four power divider, and a four-element slot leaky-wave antenna array based on SIW resonators in the TE 440 mode; the upper and lower surfaces along the length direction of the lower dielectric substrate are respectively covered with a lower metal surface and a metal ground, and four groups of periodically arranged coupled slot pairs and a GCPW feeding structure are etched on the lower metal surface; the one-to-four power divider is symmetrically placed on the lower dielectric substrate, and a group of metallized vias are uniformly etched along the outer periphery of the upper dielectric substrate; the four-element slot leaky-wave antenna array based on SIW resonators in the TE 440 mode is located on the upper dielectric substrate, and four groups of periodically arranged metallized via arrays are etched on the upper dielectric substrate. The present invention uses GCPW side feeding to effectively excite the planar antenna, the feeding form is simple, and the high-gain characteristic with ultra-low sidelobe level is achieved, which has potential application value in future 5G mobile communication, satellite communication, millimeter-wave communication and other systems.

Description

Technical Field

[0001] The present invention relates to a slot leaky-wave antenna, in particular to a millimeter-wave array antenna with high-gain and low-sidelobe level characteristics. Background Art

[0002] Large system capacity, high data rate, low latency, and massive device connectivity are the performance goals of the fifth-generation (5G) mobile communication technology. Compared with the increasingly crowded sub-6 GHz frequency band, the 5G millimeter-wave (mmW) frequency band has richer spectrum resources and available regions. However, millimeter-wave antennas have disadvantages such as large transmission losses, small structural sizes, high machining accuracies, and high machining costs.

[0003] In the design process of high-gain millimeter-wave antennas, generally speaking, the more the number of array elements, the higher the gain. However, the more complex the feeding network is, the greater the transmission loss will be. If a "large" antenna element can be used to replace the radiation effects of multiple traditional elements at the same time, the number of elements can be reduced, thereby simplifying the feeding network and reducing the feeding loss. Therefore, the concept of electrically large (ELP) size antennas has been proposed. Electrically large size antennas break through the limitation of the size of traditional resonant antennas (half-wavelength), and the antenna size can exceed one wavelength, or even multiple wavelengths.

[0004] However, when the size of the antenna element is greater than half of the operating wavelength, the element spacing increases, which will cause the antenna array to gradually generate high sidelobe levels. The generation of high sidelobe levels will inhibit the operating efficiency of the antenna and reduce the communication quality. Therefore, it is very meaningful to study high-gain millimeter-wave antenna arrays with low sidelobe levels.

[0005] Therefore, how to design the above-mentioned high-performance antennas has become a new focus. Although different methods can be used to achieve high-gain millimeter-wave antennas, it is necessary to reduce the losses caused by complex transmission lines and achieve low-sidelobe characteristics at the same time, which poses strict requirements on antenna design. In particular, it is necessary to ensure the compactness of the structure and achieve low mutual coupling characteristics between elements, which has become a difficult problem that antenna engineers urgently need to solve. Summary of the Invention

[0006] Object of the Invention: A millimeter-wave array antenna with high-gain and low-sidelobe level characteristics to solve the problems of the prior art.

[0007] Technical Solution: A millimeter-wave array antenna with high-gain and low-sidelobe level characteristics includes upper and lower dielectric substrates, a GCPW feeding structure, a one-to-four power divider, and a four-element slot leaky-wave antenna array based on the TE 440 mode of the SIW resonator;

[0008] The upper and lower surfaces along the length direction of the lower dielectric substrate are respectively covered with a lower metal surface and a metal ground. Four groups of periodically arranged coupled slot pairs and a GCPW feeding structure are etched on the lower metal surface; a one-to-four power divider is symmetrically placed on the lower dielectric substrate, and a group of metallized vias are uniformly etched along the outer periphery of the upper dielectric substrate; a four-element slot leaky wave antenna array based on the SIW resonator TE 440 mode is located on the upper dielectric substrate. Four groups of periodically arranged metallized via arrays are etched on the upper dielectric substrate. The upper surface of the upper dielectric substrate is covered with an upper metal surface, and four groups of 4×4 element slot arrays are etched on the upper metal surface;

[0009] A groove is etched at the central position on the lower side of the upper dielectric substrate for placing an End Launch connector to realize GCPW side feeding;

[0010] The upper and lower dielectric substrates are placed in alignment, and a group of circular air vias are correspondingly etched around for fixing the stack with plastic screws.

[0011] Preferably, the upper and lower dielectric substrates of the present invention are the same dielectric substrate, with a relative dielectric constant of 2.2, a loss tangent of 0.0009, both having a length of 112.1 mm and a width of 63.4 mm. The thicknesses of the upper and lower dielectric substrates are 1 mm and 0.5 mm respectively. The size of the groove etched at the central position on the lower side of the upper dielectric substrate is 20 mm×6 mm.

[0012] Preferably, the one-to-four power divider of the present invention is composed of a group of metallized vias uniformly etched along the dielectric substrate, symmetrically placed on the lower dielectric substrate, and the radius of the metallized vias is 0.15 mm.

[0013] Preferably, the four-element slot leaky wave antenna array based on the SIW resonator TE 440 mode is located on the upper dielectric substrate. Four groups of periodically arranged metallized via arrays are etched on the upper dielectric substrate, and the radius of the metallized vias is 0.15 mm.

[0014] Preferably, the length of the metal ground of the present invention is 112.1 mm and the width is 63.4 mm.

[0015] Preferably, four groups of periodically arranged coupled slot pairs are etched on the lower metal surface of the present invention. The coupled slots are 4.6 mm long and 0.7 mm wide, the distance between each group of slot pairs is 20.7 mm, and the distance between the slot pairs is 10 mm.

[0016] Preferably, four groups of 4×4 element slot arrays are etched on the upper metal surface of the present invention. The slots are 4.2 mm long and 0.9 mm wide, and the distance between each group of slot arrays is 20.7 mm.

[0017] Preferably, a set of circular air-vias are etched around the upper and lower dielectric substrates of the present invention. The radius of the air-vias is 1 mm, and the number of air-vias is 11.

[0018] Beneficial effects: The present invention designs and implements a high-gain and low-sidelobe millimeter-wave array antenna with a double-layer dielectric substrate, which has a simple structure and is easy to process and implement. It has the advantages of low profile and easy integration with planar circuits, and has potential application value in systems such as 5G mobile communication, satellite communication, and millimeter-wave communication. The slot leaky-wave antenna based on the TE mode of the SIW resonator adopted in the present invention has the characteristics of electrically large size. While achieving high-gain performance, it greatly reduces the number of radiation elements, simplifies the feeding network, and reduces the feeding loss. The one-to-four in-phase unequal-amplitude power divider on the lower dielectric substrate can improve the radiation characteristics of the antenna, greatly reduce the sidelobe level of the antenna, and thus achieve the radiation performance of low sidelobes and high gain; the four-element slot leaky-wave antenna array based on the TE mode of the SIW resonator can achieve good cross-polarization characteristics. 440 mode has the characteristics of electrically large size. While achieving high-gain performance, it greatly reduces the number of radiation elements, simplifies the feeding network, and reduces the feeding loss. The one-to-four in-phase unequal-amplitude power divider on the lower dielectric substrate can improve the radiation characteristics of the antenna, greatly reduce the sidelobe level of the antenna, and thus achieve the radiation performance of low sidelobes and high gain; the four-element slot leaky-wave antenna array based on the TE 440 mode can achieve good cross-polarization characteristics. Description of the Drawings

[0019] Figure 1 is the three-dimensional overall structure diagram of the present invention.

[0020] Figure 2 is Figure 1 the combined top view.

[0021] Figure 3 is Figure 1 the combined side view.

[0022] Figure 4 is the reflection coefficient curve diagram of the present invention.

[0023] Figure 5 is the main polarization pattern of the present invention.

[0024] Figure 6 is the cross-polarization pattern of the present invention.

[0025] Wherein: 1. Metal ground, 2. Lower dielectric substrate, 3. Lower metal surface, 4. Upper dielectric substrate, 5. Upper metal surface, 6. One-to-four power divider, 7. GCPW feeding structure, 8. Four groups of periodically arranged coupled slot pairs, 9. Four groups of periodically arranged metallized via arrays, 10. Four groups of periodically arranged 4×4 element slot arrays, 11. A set of circular air-vias etched corresponding to the upper and lower dielectric substrates. Detailed Embodiments

[0026] Such as Figure 1 , Figure 2 , Figure 3As shown, a millimeter-wave array antenna with high gain and low sidelobe level characteristics, including upper and lower dielectric substrates, a GCPW feeding structure, a one-to-four power divider, and a four-element slot leaky-wave antenna array based on the SIW resonator TE 440 mode.

[0027] The present invention has a compact structure and is composed of upper and lower dielectric substrates. The upper and lower surfaces of the lower dielectric substrate 2 are respectively covered with a lower metal surface 3 and a metal ground 1. Four groups of periodically arranged coupling slot pairs 8 and a GCPW feeding structure 7 are etched on the lower metal surface 3. The one-to-four power divider 6 is symmetrically placed on the lower dielectric substrate 2, and a group of circular air-vias 11 are etched uniformly along the dielectric substrate; the four-element slot leaky-wave antenna array based on the SIW resonator TE 440 mode is located on the upper dielectric substrate 4. Four groups of periodically arranged metallized via arrays 9 are etched on the upper dielectric substrate 4. The upper surface of the upper dielectric substrate 4 is covered with an upper metal surface 5, and four groups of 4×4 element slot arrays 10 are etched on the upper metal surface 5.

[0028] A groove is etched at the central position on the lower side of the upper dielectric substrate 4, which is convenient for placing an End Launch connector at this position later, enabling GCPW side feeding and completing the effective excitation of the planar antenna;

[0029] The upper and lower dielectric substrates are placed in alignment, and a group of circular air-vias 11 are etched correspondingly around them, and they can be fixed and stacked by plastic screws later.

[0030] In a further embodiment, the upper and lower dielectric substrates are the same dielectric substrate, with a relative dielectric constant of 2.2, a loss tangent of 0.0009, a length of 112.1 mm, a width of 63.4 mm, and the thicknesses of the upper and lower dielectric substrates are 1 mm and 0.5 mm respectively. As Figure 2 shown, the size of the groove etched at the central position on the lower side of the upper dielectric substrate is 20 mm×6 mm.

[0031] In a further embodiment, the one-to-four power divider 6 is composed of a group of metallized vias etched uniformly along the dielectric substrate, symmetrically placed on the lower dielectric substrate 2, and the radius of the metallized vias is 0.15 mm.

[0032] In a further embodiment, the four-element slot leaky-wave antenna array based on the SIW resonator TE 440 mode is located on the upper dielectric substrate 4. Four groups of periodically arranged metallized via arrays are etched on the upper dielectric substrate 4, and the radius of the metallized vias is 0.15 mm.

[0033] In a further embodiment, the length of the metal ground 1 of the lower dielectric substrate 2 is 112.1 mm and the width is 63.4 mm.

[0034] In a further embodiment, four sets of periodically arranged coupled slot pairs are etched on the lower metal surface 3 of the lower dielectric substrate 2. The coupled slots are 4.6 mm long and 0.7 mm wide. The distance between each set of slot pairs is 20.7 mm, and the distance between the slot pairs is 10 mm.

[0035] In a further embodiment, a 4×4 element slot array is etched on the upper metal surface 5 of the upper dielectric substrate 4. The slots are 4.2 mm long and 0.9 mm wide. The distance between each set of slot arrays is 20.7 mm.

[0036] In a further embodiment, a set of circular air-vias are correspondingly etched around the upper and lower dielectric substrates. The radius of the air-vias is 1 mm, and the number of air-vias is 11.

[0037] In a still further embodiment, when the antenna of the present invention operates, the structure is excited by a coplanar waveguide GCPW side-feed method.

[0038] Energy is input by the coaxial probe of the 50Ω End Launch connector. The inner core layer of the coaxial probe is connected to the GCPW feeding structure etched on the lower metal surface 3 of the lower dielectric substrate 2, and the lower metal surface 3 of the lower dielectric substrate 2 is connected to the outer core layer of the coaxial probe. The energy is transmitted to the radiation unit along the one-to-four power divider 6 through the GCPW-SIW transition structure. The radiation unit is a four-element slot leaky wave antenna array based on the SIW cavity TE 440 mode, which is composed of a periodically arranged metallized via array 9 etched on the upper dielectric substrate and a 4×4 element slot array etched on the upper metal surface of the upper dielectric substrate. The one-to-four power divider 6 located on the lower dielectric substrate transmits energy to the four-element slot leaky wave antenna array based on the SIW cavity TE 440 mode through slot coupling of four sets of periodically arranged coupled slot pairs 8 etched on the lower metal surface 3 of the lower dielectric substrate 2.

[0039] As Figure 1 shown, the slot leaky wave antenna based on the SIW cavity TE 440 mode has electrically large size characteristics. While achieving high gain performance, the number of radiation units is greatly reduced, realizing the purpose of simplifying the feeding network and reducing the feeding loss.

[0040] On the one hand, as Figure 4 shown, in the frequency band range from 26.7 GHz to 27.8 GHz, the reflection coefficient (S11) of the array antenna is less than -10 dB, indicating that the working frequency band of the well-matched array antenna covers the frequency band range from 26.7 GHz to 27.8 GHz.

[0041] On the other hand, combining Figure 5 and Figure 6As shown, the one-to-four in-phase unequal-amplitude power divider of the lower dielectric substrate can improve the radiation characteristics of the antenna, greatly reduce the sidelobe level of the antenna, and thus achieve the radiation performance of low sidelobes and high gain; the four-element slot leaky-wave antenna array based on the SIW resonator TE 440 mode can achieve good cross-polarization characteristics. Figure 5 And Figure 6 are respectively the two-dimensional far-field radiation patterns of the array antenna on the Phi = 0° plane and the Phi = 90° plane (the solid line is the main polarization pattern curve, and the dashed line represents the cross-polarization pattern curve). It can be seen that the maximum gain of the antenna reaches 21.5 dBi, the sidelobe level of the antenna in the Phi = 0° plane is -19 dB, and the cross-polarization reaches 37.8 dB; while the sidelobe level of the antenna in the Phi = 90° plane is -20.8 dB, and the cross-polarization reaches 37.8 dB.

[0042] In summary, the present invention has the following advantages: effective excitation of the planar antenna is achieved through a 50Ω End Launch connector, enabling the array antenna to have a simple and convenient feeding method, which is very convenient for processing, fixing, and testing; in addition to achieving good impedance matching, the GCPW-SIW transition structure also has the low-loss characteristic compared with microstrip transmission lines in the millimeter wave band; the one-to-four in-phase unequal-amplitude power divider can improve the radiation characteristics of the antenna and achieve an ultra-low sidelobe level; the leaky-wave structure based on the SIW resonator TE 440 mode can achieve good antenna gain and low sidelobe and low cross-polarization characteristics. The present invention designs and implements a high-gain low-sidelobe millimeter-wave array antenna with a double-layer dielectric substrate, which has a simple structure, is easy to process and implement, has the advantages of a low profile and easy integration with planar circuits, and has potential application value in systems such as 5G mobile communication, satellite communication, and millimeter-wave communication.

[0043] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

Claims

1. A millimeter-wave array antenna with the characteristics of high gain and low sidelobe level, characterized in that: It includes upper and lower dielectric substrates, a GCPW feeding structure, a one-to-four power divider, and a four-element slot leaky wave antenna array based on the SIW resonator TE 440 mode; The upper and lower surfaces along the length direction of the lower dielectric substrate are respectively covered with a lower metal surface and a metal ground. Four groups of periodically arranged coupled slot pairs and a GCPW feeding structure are etched on the lower metal surface; A one-to-four power divider is symmetrically placed on the lower dielectric substrate, and a group of metallized vias are uniformly etched along the outer periphery of the upper dielectric substrate; A four-element slot leaky wave antenna array based on the SIW resonator TE 440 mode is located on the upper dielectric substrate. Four groups of periodically arranged metallized via arrays are etched on the upper dielectric substrate. The upper surface of the upper dielectric substrate is covered with an upper metal surface, and four groups of 4×4 element slot arrays are etched on the upper metal surface; A groove is etched at the central position on the lower side of the upper dielectric board for placing an End Launch connector to achieve side feeding of GCPW. The upper and lower dielectric boards are placed in alignment, and a group of circular air-vias are etched correspondingly around them for fixing the stacked boards with plastic screws.

2. The millimeter-wave array antenna with high-gain and low-sidelobe level characteristics according to claim 1, wherein The above upper and lower dielectric boards are the same kind of dielectric substrates, with a relative dielectric constant of 2.2, a tangent of loss angle of 0.0009, a length of 112.1 mm, a width of 63.4 mm, and the thicknesses of the upper and lower dielectric boards are 1 mm and 0.5 mm respectively; the size of the groove etched at the central position on the lower side of the upper dielectric board is 20 mm × 6 mm.

3. The millimeter-wave array antenna with high-gain and low sidelobe level characteristics according to claim 1, characterized in that, The above one-to-four power divider is composed of a group of metallized vias etched uniformly along the dielectric board and symmetrically placed on the lower dielectric board, and the radius of the metallized vias is 0.15 mm.

4. The millimeter-wave array antenna with high-gain and low sidelobe level characteristics according to claim 1, characterized in that, The radius of the above metallized vias is 0.15 mm.

5. The millimeter-wave array antenna with high-gain and low sidelobe level characteristics according to claim 1, wherein The length of the above metal ground is 112.1 mm and the width is 63.4 mm.

6. The millimeter-wave array antenna with high-gain and low sidelobe level characteristics according to claim 1, wherein Four groups of periodically arranged coupling slot pairs are etched on the above lower metal surface, the coupling slots are 4.6 mm long and 0.7 mm wide, the distance between each group of slot pairs is 20.7 mm, and the distance between the slot pairs is 10 mm.

7. The millimeter-wave array antenna with high-gain and low sidelobe level characteristics according to claim 1, characterized in that, Four groups of 4×4 element slot arrays are etched on the above upper metal surface, the slots are 4.2 mm long and 0.9 mm wide, and the distance between each group of slot arrays is 20.7 mm.

8. A millimeter-wave array antenna having high-gain and low-sidelobe level characteristics according to claim 1, wherein, A group of circular air-vias are etched correspondingly around the above upper and lower dielectric boards, the radius of the air-vias is 1 mm, and the number of air-vias is 11.

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