Novel ultra-wideband low-profile microstrip array antenna based on tapered slot coupling

Abstract

The application provides a novel ultra-wideband low-profile microstrip array antenna based on a gradient slot coupling, and relates to the technical field of antenna engineering. The novel ultra-wideband low-profile microstrip array antenna based on the gradient slot coupling comprises a ground plate, a lower dielectric, a gradient feed line, an upper dielectric and a radiation unit. The ground plate is provided with a gradient slot. The lower dielectric is arranged on one side of the ground plate. The gradient feed line is arranged on the side of the lower dielectric away from the ground plate. The upper dielectric is arranged on the side of the ground plate provided with the gradient slot. The radiation unit is arranged on the side of the upper dielectric away from the ground plate. In the application, the grid radiation unit is matched with the gradient slot coupling structure to reduce the circuit Q value and realize continuous impedance transformation. The impedance bandwidth is significantly widened while the low profile and miniaturization are maintained. The units are periodically arranged to form a surface array, the high gain and anti-interference requirements are met, and the application range of the antenna is effectively expanded.

Description

Technical Field

[0001] This invention relates to the field of antenna engineering technology, specifically to a novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling. Background Technology

[0002] With the rapid development of modern wireless communication, electronic reconnaissance and radar technologies, the system has placed increasingly higher demands on antenna equipment. It not only needs to have wide bandwidth characteristics to adapt to multi-band operation, but also needs to maintain a low profile structure to facilitate high-density integration with the carrier platform.

[0003] However, existing microstrip patch antennas typically employ traditional rectangular patch structures, which are equivalent to high-Q resonant circuits, resulting in narrow impedance bandwidth and a lack of effective mutual coupling mechanisms. At the same time, existing ultra-wideband antennas mostly use feed structures with high profiles, making it difficult to simultaneously achieve the requirements of low profile, miniaturization, and high integration, thus limiting their application in automotive and portable devices.

[0004] Therefore, those skilled in the art have provided novel ultrawideband low-profile microstrip array antennas based on gradient slot coupling to solve the problems mentioned in the background art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling, which solves the problems of narrow bandwidth, low impedance matching flexibility, high profile leading to integration difficulties, and difficulty in meeting specific gain and beam characteristics of existing antennas.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling includes a ground plane, a lower dielectric layer, a gradient feed line, an upper dielectric layer, and a radiating element. A gradient slot is formed on the ground plane. The lower dielectric layer is disposed on one side of the ground plane. The gradient feed line is disposed on the side of the lower dielectric layer away from the ground plane. The upper dielectric layer is disposed on the side of the ground plane with the gradient slot. The radiating element is disposed on the side of the upper dielectric layer away from the ground plane. The gradient feed line couples and feeds the radiating element through the gradient slot. The above technical solution, through the combination of gridded radiating elements and gradient slot coupling structure, reduces the circuit Q value and achieves continuous impedance transformation. While maintaining low profile and miniaturization, it significantly broadens the impedance bandwidth. By periodically arranging the elements to form an array, it meets the requirements of high gain and anti-interference, effectively expanding the application range of the antenna.

[0007] Furthermore, the radiating unit includes multiple metal grids of different lengths, which are arranged side by side to form a mutual coupling structure. The impedance bandwidth is increased by using metal grids of different lengths to correspond to different radiation frequencies and by the mutual coupling effect between the grids. The above technical solution can change the current distribution path on the antenna surface and reduce the Q value of the equivalent resonant circuit, thereby generating multiple adjacent resonant points and significantly broadening the impedance bandwidth of the antenna.

[0008] Furthermore, the gradient slot is formed in an exponential curve shape on the floor, and the width of the gradient slot gradually changes along the transmission direction of the gradient feed line. The maximum width of the gradient slot corresponds to the lower limit frequency of the antenna operating bandwidth, and the minimum width corresponds to the upper limit frequency of the antenna operating bandwidth. By utilizing the above technical solutions and the proportional conversion principle of non-frequency-variable antennas, the upper and lower limits of the antenna's operating frequency band can be precisely controlled, thereby flexibly covering the target ultra-wide frequency band and significantly improving the upper limit of the designed bandwidth.

[0009] Furthermore, the gradient feed line has an exponential curve shape, which matches the shape of the gradient gap, and the width of the gradient feed line varies with the transmission distance to achieve a continuous gradient of impedance. The above technical solution can form a special structural fit with the gradient gap, and achieve continuous and smooth impedance transformation based on the exponential curve characteristics, thereby maintaining efficient electromagnetic coupling feeding and good standing wave characteristics in a wide frequency band.

[0010] Furthermore, the gradient feed line does not directly contact the floor, but is isolated from the radiating unit by the lower dielectric and the upper dielectric, forming a double-layer dielectric plate coupling structure; By employing the above technical solutions, while avoiding direct contact between conductors to reduce losses, the physical profile height of the antenna is effectively reduced, achieving miniaturization and weight reduction of the antenna, and significantly improving its integration with other electronic system modules.

[0011] Furthermore, the ground plane, lower dielectric, tapered feed line, upper dielectric, and radiating element together constitute an antenna element. The antenna includes multiple antenna elements arranged in an array. The multiple antenna elements are periodically extended and arranged in the azimuth and elevation planes to form a planar array structure. The above technical solutions can meet the system's technical requirements for specific gain and beamwidth, achieve high-resolution detection of targets and anti-interference capabilities, and significantly expand the application range of antennas in vehicle-mounted and portable devices.

[0012] This invention provides a novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling. It offers the following advantages: 1. This invention provides a novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling. By designing the radiating element as a mutually coupled structure composed of multiple gratings of different lengths, the current distribution path on the antenna surface is changed and the Q value of the equivalent resonant circuit is reduced, thereby generating multiple adjacent resonant points and significantly widening the impedance bandwidth of the antenna.

[0013] 2. This invention provides a novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling. By using a gradient feed line with an exponential curve shape and a gradient slot on the ground plane for special structural matching, it can achieve continuous impedance transformation based on the proportional transformation principle of non-frequency-varying antennas, realize electromagnetic coupling feeding covering an ultra-wide frequency band, and significantly improve the antenna design flexibility and bandwidth limit.

[0014] 3. This invention provides a novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling. By layering the gradient feed line and the ground plane and forming a slot coupling structure through dielectric isolation, the physical profile height is effectively reduced while avoiding direct contact and reducing losses. This achieves miniaturization and weight reduction of the antenna, and significantly improves the integration of the antenna with other electronic system modules.

[0015] 4. This invention provides a novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling. By periodically extending and arranging antenna elements in the azimuth and elevation planes to form a planar array structure, it meets the technical specifications of specific gain and beamwidth, realizing the application requirements of the system for high-resolution detection and anti-interference capabilities, and significantly expanding the application range of the antenna in vehicle-mounted and portable devices. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the external structure of the antenna unit of the present invention; Figure 2 This is a block diagram of the antenna unit composition of the present invention; Figure 3 This is a schematic diagram of the radiation unit of the present invention; Figure 4 This is a schematic diagram of the floor with gradient gaps according to the present invention; Figure 5 This is a schematic diagram of the gradient feed line of the present invention; Figure 6 This is a schematic diagram of the gradual coupling power supply method of the present invention; Figure 7 This is a schematic diagram of the external structure of the array antenna of the present invention. Figure 1 ; Figure 8 This is a schematic diagram of the external structure of the array antenna of the present invention. Figure 2 .

[0017] Explanation of reference numerals in the attached figures: 1. Floor; 2. Gradient gap; 3. Lower medium; 4. Gradient feeder; 5. Upper medium; 6. Radiating unit. Detailed Implementation

[0018] 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, and 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.

[0019] Example 1: like Figure 1-6 As shown, this embodiment of the invention provides a novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling, including a ground plane 1, a lower dielectric 3, a gradient feed line 4, an upper dielectric 5, and a radiating element 6. A gradient slot 2 is provided on the ground plane 1. The lower dielectric 3 is disposed on one side of the ground plane 1. The gradient feed line 4 is disposed on the side of the lower dielectric 3 away from the ground plane 1. The upper dielectric 5 is disposed on the side of the ground plane 1 where the gradient slot 2 is provided. The radiating element 6 is disposed on the side of the upper dielectric 5 away from the ground plane 1. The gradient feed line 4 couples and feeds the radiating element 6 through the gradient slot 2. By combining the gridded radiating element 6 with the gradient slot 2 coupling structure, the Q value of the circuit is reduced and continuous impedance transformation is achieved. While maintaining low profile and miniaturization, the impedance bandwidth is significantly widened. The periodic arrangement of the elements forms a planar array, which meets the requirements of high gain and anti-interference, effectively expanding the application range of the antenna.

[0020] like Figure 1 and Figure 2 As shown, each independent antenna unit adopts a double-layer dielectric substrate stacked structure, mainly composed of core components such as a gradient feed line 4, a ground plane 1 with gradient gaps 2, and a radiating element 6.

[0021] like Figure 7 and Figure 8 As shown, this invention provides a novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling, aiming to solve the problems of narrow bandwidth of traditional microstrip antennas and high profile and difficulty in integration of traditional ultra-wideband antennas. The array antenna is composed of multiple identical antenna elements arranged according to a certain rule. In practical applications, a suitable number of antenna elements can be selected for arraying based on the specific requirements of the system for antenna gain, beamwidth, and other technical indicators. For example, in this embodiment, an array structure containing 100 elements is constructed by arranging 10 antenna elements each in the azimuth and elevation planes to meet the requirements of high-gain detection and anti-interference.

[0022] Technical solutions for radiative unit gridding (combined with) Figure 1 and Figure 4 (as shown) This invention innovatively designs the traditional rectangular patch radiating unit into a mutually coupled structure composed of multiple grids of different lengths (e.g., Figure 4 (As shown). Its working principle is that different lengths of radiating gratings correspond to different radiation frequencies. Through the mutual coupling effect between the gratings, the current distribution path on the antenna surface can be effectively changed, thereby significantly increasing the impedance bandwidth and achieving broadband characteristics.

[0023] Theoretically, the input impedance of most microstrip antennas is highly sensitive to frequency changes; therefore, widening the bandwidth hinges on improving impedance characteristics. Generally, the relative bandwidth of an antenna is the absolute bandwidth divided by the antenna's center frequency, expressed as: and These are the upper and lower frequency limits for meeting bandwidth requirements. When the relative bandwidth is greater than 20%, it is defined as an ultra-wideband antenna. A traditional microstrip patch antenna is equivalent to a high-Q parallel resonant circuit, and its bandwidth is calculated using the following formula:

[0024] BW represents bandwidth, Q is quality factor, and VSWR is voltage standing wave ratio. Therefore, reducing the Q value of the equivalent resonant circuit is a fundamental way to broaden the bandwidth.

[0025] This invention combines the advantages of techniques such as "changing the patch shape" and "pattern slotting," transforming the traditional rectangular radiating unit into a novel radiating unit formed by coupling grids of varying lengths. This structure not only reduces the Q value of the circuit through shape change but also utilizes a coupling principle similar to multiple resonant points to generate new resonant points near the original resonant frequency, thereby overcoming the narrow bandwidth limitation of traditional patch elements.

[0026] Technical solutions for flooring with gradient gaps (combined with...) Figure 2 (as shown) Floor 1 is located on the lower medium 3 board, and special gradient gaps 2 are opened on it, such as... Figure 2 As shown. Traditional slots are generally designed as rectangles, but their bandwidth is limited. This invention creates a gradient slot by removing a portion consisting of four gradient curves from the entire floor 1. This non-rectangular gradient design can effectively adjust the electromagnetic field distribution around the slot, thereby increasing the impedance bandwidth and further widening the antenna's frequency band.

[0027] Technical solutions for gradual coupling power supply (combined with) Figure 2 and Figure 6 (as shown) Based on the characteristics of the gradient exponential curve and the principle of antenna scaling, the theoretical operating bandwidth of a gradient-coupled feeder can be infinite, meaning that the antenna's performance parameters are independent of frequency. The scaling principle states that when the size of an antenna is multiplied by a factor K, the antenna's performance parameters remain consistent with the original antenna. Therefore, we can conclude that the antenna's performance characteristics at any frequency point f are consistent with K. The properties of f remain consistent. Let K be such that its value is 1. Then we can deduce that f and K... The performance variation between f is extremely small. This is proven below with mathematical derivation: Assuming the gradient coupling structure is placed on the xoy horizontal plane, the equation of the gradient exponential curve in the feed direction is expressed as:

[0028] According to the proportional transformation principle of non-frequency-converting antennas:

[0029] Where x can take any value. Taking the partial differential equations for C and x on both sides of the equation, we get:

[0030] And because:

[0031] By summarizing and organizing, we can obtain the following equation:

[0032] The above proof demonstrates that the performance parameters of the tapered coupling feed are indeed independent of the frequency point. In practical designs, the maximum width of the tapered coupling feed and the slot corresponds to the lowest frequency point of the antenna bandwidth, and the minimum width corresponds to the highest frequency point of the antenna bandwidth. Therefore, designers can adapt to different frequency bands by adjusting the tapered dimensions according to specific bandwidth requirements, thereby achieving flexible design requirements.

[0033] Working Principle: After signal input, the signal first passes through an exponentially gradient microstrip feed line. Based on transmission line theory, the gradient structure allows the characteristic impedance to change continuously and smoothly along the transmission direction, achieving broadband impedance matching from the feed source to the radiating aperture and effectively eliminating reflections caused by abrupt size changes in traditional structures. Subsequently, electromagnetic energy passes through the gradient gap 2 on the floor 1, utilizing the transverse magnetic field component of the gap to generate strong coupling and transfer energy to the upper layer. The radiating element 6 constructs multiple resonant circuits using metal grids of different lengths. Near-field mutual coupling exists between the grids, exciting multiple adjacent resonant modes. The superposition of these modes diversifies the current path, thereby significantly reducing the Q value of the equivalent circuit and transforming narrowband point-frequency resonance into broadband continuous coverage. Finally, the array uses spatial beamforming with a periodic structure to superimpose the energy radiated by the elements in phase in space, achieving highly directional radiation.

[0034] The following points should be noted in this article: 1. The accompanying drawings of the embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures can be referred to in a general design.

[0035] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling, comprising a ground plane (1), a lower dielectric layer (3), a gradient feed line (4), an upper dielectric layer (5), and a radiating element (6), characterized in that: The floor (1) has a gradient gap (2), the lower medium (3) is located on one side of the floor (1), the gradient feed line (4) is located on the side of the lower medium (3) away from the floor (1), the upper medium (5) is located on the side of the floor (1) with the gradient gap (2), the radiation unit (6) is located on the side of the upper medium (5) away from the floor (1), and the gradient feed line (4) couples and feeds power to the radiation unit (6) through the gradient gap (2).

2. The novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling according to claim 1, characterized in that: The radiation unit (6) includes multiple metal grids of different lengths, which are arranged side by side to form a mutual coupling structure. The impedance bandwidth is increased by the different radiation frequencies corresponding to the metal grids of different lengths and the mutual coupling effect between the grids.

3. The novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling according to claim 1, characterized in that: The gradient slot (2) is opened on the floor (1) in an exponential curve shape. The width of the gradient slot (2) gradually changes along the transmission direction of the gradient feed line (4). The maximum width of the gradient slot (2) corresponds to the lower limit frequency of the antenna operating bandwidth, and the minimum width corresponds to the upper limit frequency of the antenna operating bandwidth.

4. The novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling according to claim 1, characterized in that: The gradient feed line (4) is in the shape of an exponential curve, and its shape matches the shape of the gradient gap (2). The width of the gradient feed line (4) varies with the transmission distance to achieve a continuous gradient of impedance.

5. The novel ultra-wideband low-profile microstrip array antenna based on gradient slot coupling according to claim 1, characterized in that: The gradient feed line (4) is not in direct contact with the floor (1). It is isolated from the radiation unit (6) by the lower medium (3) and the upper medium (5), forming a double-layer dielectric plate coupling structure.

6. The novel ultrawideband low-profile microstrip array antenna based on gradient slot coupling according to claim 1, characterized in that: The ground plane (1), the lower dielectric (3), the gradient feed line (4), the upper dielectric (5), and the radiating element (6) together form an antenna unit. The antenna includes multiple antenna units arranged in an array. The multiple antenna units are periodically extended and arranged in the azimuth and elevation planes to form a planar array structure.

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