A method for reducing the influence of the size of the ground plane of a slot-coupled microstrip antenna

Abstract

The present invention relates to a method for suppressing the generation of surface wave energy of an antenna by loading four L-shaped sawtooth slots on the ground plane of a slot-coupled microstrip antenna, reducing the influence of antenna performance variation with the size of the ground plane, and achieving the stability of the performance of the antenna element. The antenna implemented by the method proposed in the present invention, as an element in the active phased array, greatly optimizes and improves the isolation characteristic of the element in the array, and effectively ensures the performance of the entire array antenna. The method proposed in the present invention has positive guiding and reference significance for other frequency bands or other forms of slot-coupled microstrip antennas.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a method for reducing the influence of the ground size of a slot-coupled microstrip antenna on the antenna performance. The antenna structure realized by this method is compact, low-profile, easy to integrate, and low-cost, and is an ideal unit form for constructing a general phased array antenna system. Background Art

[0002] As an important part of an active phased array, the characteristics of the antenna element play a crucial role in the array performance. The matching and coupling characteristics of the element determine the spatial scanning ability of the array. The performance of traditional slot-coupled microstrip antennas is extremely vulnerable to the perturbation of the ground size due to the generation of surface wave energy, and it simply cannot be used as an antenna element of an active phased array. In order to ensure the independence of the element performance and antenna parameters in the array as much as possible, and make the antenna performance not change with antenna parameters such as the ground size, some scholars have proposed to set metallized isolation vias around the radiation patch layer and the feeding network layer to form a closed cavity structure inside the dielectric substrate, so as to achieve the purpose of suppressing surface wave energy, optimize and improve the isolation characteristics of the elements in the array, and reduce the perturbation of the mutual coupling between elements on the antenna performance. However, this way of setting metallized isolation vias destroys the continuity of the ground layer with slot coupling, and in the case of multiple layers of the antenna dielectric substrate, it needs to be processed into metallized blind vias, which is complex in processing technology and high in cost. Summary of the Invention

[0003] Technical Problems to be Solved

[0004] Due to the appearance of surface wave energy, the performance of the microstrip antenna is extremely vulnerable to the influence of the ground size. Especially when using slot-coupled microstrip antenna elements to form an array antenna, the mutual coupling between elements will cause serious perturbation to the antenna performance. Therefore, measures must be taken to suppress the surface wave energy of the slot-coupled microstrip antenna.

[0005] Aiming at the fact that the performance of the slot-coupled microstrip antenna element is extremely vulnerable to the change of the ground size, the present invention provides a method for reducing the influence of the ground size of the slot-coupled microstrip antenna, loading four L-shaped serrated slots on the ground layer with slot coupling to suppress the surface wave energy of the antenna element, reduce the perturbation of the mutual coupling between elements in the antenna array on the antenna performance, and achieve the purpose of maintaining the independence of the element performance in the array.

[0006] Technical Solution

[0007] A method for reducing the influence of the ground size of a slot-coupled microstrip antenna, characterized in that L-shaped serrated slots are introduced on the ground of the slot-coupled microstrip antenna to reduce the influence of the ground size on the antenna performance.

[0008] A further technical solution of the present invention: There are 4 L-shaped sawtooth slots.

[0009] An antenna structure for reducing the influence of the ground size of a slot-coupled microstrip antenna, characterized in that it is composed of three dielectric plates laminated together, which are the top dielectric plate, the middle dielectric plate and the bottom dielectric plate from top to bottom. The three dielectric plates are connected into an integral body through the first prepreg and the second cured film; the radiation patch is located on the upper surface of the top dielectric plate, the feeder in the form of a strip line is located on the upper surface of the bottom dielectric plate, the coupling radiation slot is located on the upper surface of the middle dielectric plate, and the energy transmitted on the strip line is coupled to the radiation patch through the coupling radiation slot. Four L-shaped sawtooth slots are located on the ground layer with the radiation coupling slot and are symmetrically distributed at the four diagonals of the radiation coupling slot.

[0010] A further technical solution of the present invention: The radiation coupling slot is in the shape of an H.

[0011] A further technical solution of the present invention: The radiation patch is rectangular.

[0012] A further technical solution of the present invention: The lengths L1 and L2 of the L-shaped sawtooth slot are equal to the length PL of the radiation patch. The length L3 of the sawtooth of the L-shaped sawtooth slot is 0.15 times of L1, and the width W1 of the sawtooth of the L-shaped sawtooth slot is equal to the width SW of the coupling radiation slot.

[0013] A further technical solution of the present invention: The middle dielectric plate and the bottom dielectric plate have the same thickness.

[0014] A further technical solution of the present invention: The first prepreg and the second cured film have the same thickness.

[0015] Beneficial effects

[0016] A method for reducing the influence of the ground size of a slot-coupled microstrip antenna provided by the present invention only needs to load some L-shaped sawtooth slots on the ground layer with the coupling slot to achieve the same or even better effect as setting metallized isolation vias. Moreover, the method proposed by the present invention has a simple processing technology and low cost. The performance of the antenna unit is stable. When it is used as an active phased array antenna unit, it can improve the isolation characteristics of the units in the array and reduce the mutual coupling effect between the units to make the performance of the entire array antenna reach the optimal. The method proposed by the present invention has positive guiding and reference significance for other frequency bands or other forms of slot-coupled microstrip antennas. Description of the drawings

[0017] The drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference signs represent the same components.

[0018] Figure 1Schematic diagram of the hierarchical structure of the slot-coupled microstrip antenna unit according to an embodiment of the present invention;

[0019] Figure 2 Schematic diagram of the slot-coupled microstrip antenna unit according to an embodiment of the present invention;

[0020] Figure 3 Simulation model diagram of the slot-coupled microstrip antenna according to an embodiment of the present invention;

[0021] Figure 4 Graph of the standing wave of the traditional slot-coupled microstrip antenna varying with the size of the ground plane;

[0022] Figure 5 Graph of the standing wave of the slot-coupled microstrip antenna with loaded L-shaped serrated slots proposed in an embodiment of the present invention varying with the size of the ground plane;

[0023] Figure 6 Radiation pattern of the slot-coupled microstrip antenna with loaded L-shaped serrated slots proposed in an embodiment of the present invention.

[0024] 1 - Top dielectric board, 2 - Intermediate dielectric board, 3 - Lower dielectric board, 4 - First prepreg, 5 - Second prepreg, 6 - Radiation patch layer, 7 - Ground layer, 8 - Feeder layer, 9 - Grounding layer, 10 - Overall antenna structure, 11 - Radiation patch, 12 - Coupling slot, 13 - Feeder, 14 - L-shaped serrated slot Detailed implementation manners

[0025] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present 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 only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] This embodiment proposes a method for reducing the influence of the change in the size of the ground plane of the slot-coupled microstrip antenna on the antenna performance. Refer to the attached Figure 1As shown in the figure, it includes three dielectric plates, namely the top dielectric plate 1 with a thickness of subh1, the middle dielectric plates 2 and the bottom dielectric plate 3 both with a thickness of sub2. The three dielectric plates are connected into a whole by a prepreg with a thickness of hp. The rectangular radiation patch 11 is located on the top dielectric plate 1, the feeder 13 in the form of a stripline is located on the bottom dielectric plate 3, the coupling radiation slot 12 is located on the ground plane 7, and the energy transmitted on the stripline-form feeder is coupled to the radiation patch 11 through the coupling slot 12. Four L-shaped sawtooth slots 14 are located on the ground plane 7 with the coupling slot 12, symmetrically distributed at the four diagonals of the coupling slot 12. The four L-shaped sawtooth slots cut off the current distribution on the ground plane 7, effectively suppressing the generation of surface wave energy of the antenna element, so that the antenna realizes ideal and stable radiation in space, and its performance will not be affected by the change of the size of the ground plane.

[0027] Referring to the appendix Figure 2 , in the embodiment of the present invention, the three dielectric plates are all selected as Taconic TSM-DS3 with a dielectric constant of 3.0. The side length of the square dielectric plate is GNDW, the operating frequency of the antenna is in the Ka band, and the center frequency is 34.5 GHz. The lengths L1 and L2 of the L-shaped sawtooth slots are basically equivalent to the length PL of the radiation patch, the length L3 of the sawtooth is about 0.15 times of L1, and the width W1 of the L-shaped sawtooth slot is equal to the width SW of the coupling slot.

[0028] Referring to the appendix Figure 3 , is the simulation model of the slot-coupled microstrip antenna loaded with L-shaped sawtooth slots proposed in the embodiment of the present invention, and the simulation tool is HFSS 15.0.

[0029] Referring to the appendix Figure 4 , is the variation diagram of the standing wave of the traditional slot-coupled microstrip antenna with the floor size GNDW. There is only the coupling slot 12 on the ground plane 7 of the traditional slot-coupled microstrip antenna, without loading other slots and without taking other measures to suppress the surface wave energy. It can be seen from the figure that the standing wave of the antenna in the frequency range of 33.0 GHz to 36.5 GHz changes very violently with the change of the dielectric plate size GNDW.

[0030] Referring to the appendix Figure 5 , is the variation diagram of the standing wave of the antenna element loaded with L-shaped sawtooth slots proposed in the embodiment of the present invention with the floor size GNDW. It can be seen from the figure that the standing wave of the antenna in the frequency range of 33.0 GHz to 36.5 GHz is all below 2, and it maintains a high consistency with the change of the dielectric plate size GNDW, and the antenna performance is very stable.

[0031] Referring to the appendix Figure 6 , is the radiation pattern of the slot-coupled microstrip antenna loaded with L-shaped sawtooth slots proposed in the embodiment of the present invention, and the frequency is 34.5 GHz.

[0032] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for reducing the influence of the size of the ground plane of a slot-coupled microstrip antenna, characterized in that An L-shaped serrated slot is introduced on the ground of the slot-coupled microstrip antenna to reduce the influence of the ground size on the antenna performance; there are 4 L-shaped serrated slots, and the 4 L-shaped serrated slots are located on the ground layer with a radiation coupling slot, and are symmetrically distributed at the four diagonals of the radiation coupling slot.

2. An antenna structure obtained by the method according to claim 1, characterized in that: It is composed of three dielectric plates laminated together. From top to bottom, they are the top dielectric plate (1), the middle dielectric plate (2) and the bottom dielectric plate (3). The three dielectric plates are connected into a whole through the first prepreg (4) and the second curing sheet (5); the radiation patch (11) is located on the upper surface of the top dielectric plate (1), the feeder (13) in the form of a strip line is located on the upper surface of the bottom dielectric plate (3), the coupling radiation slot (12) is located on the upper surface of the middle dielectric plate (2), and the energy transmitted on the feeder (13) in the form of a strip line is coupled to the radiation patch (11) through the coupling radiation slot (12). Four L-shaped serrated slots (14) are located on the ground layer (7) with a radiation coupling slot (12), and are symmetrically distributed at the four diagonals of the radiation coupling slot (12); the radiation coupling slot (12) is of H type; the radiation patch (11) is rectangular; the lengths L1 and L2 of the L-shaped serrated slot (14) are equal to the length PL of the radiation patch (11), the length L3 of the serration of the L-shaped serrated slot (14) is 0.15 times of L1, and the width W1 of the serration of the L-shaped serrated slot (14) is equal to the width SW of the coupling radiation slot (12); the middle dielectric plate (2) and the bottom dielectric plate (3) have the same thickness; the first prepreg (4) and the second curing sheet (5) have the same thickness.

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