Structure and method for achieving wide-bandwidth beam characteristics of antennas based on open resonant rings

Abstract

This invention discloses a structure and method for achieving wide-bandwidth beam characteristics based on an open-circuit resonator, solving the problems of wide-bandwidth angular domain, compact structure, and low cost compatibility in radar detection. The parasitic structure proposed in this invention is an open-circuit resonator array, composed of stacked subarrays of different frequency bands that are interconnected and cover the antenna's frequency band. The method includes designing the parasitic structure; stacking and assembling the arrays according to the number and frequency bands of the antenna stator arrays; combining the parasitic structure with the antenna; and achieving wide-bandwidth beam characteristics. This invention utilizes the omnidirectional radiation characteristics of the open-circuit resonator to form an array, extending the antenna's beamwidth over a wide range. The open-circuit resonator unit is relatively small, and this invention achieves beam extension functionality within a compact space, exhibiting miniaturization characteristics, and can be applied to small computers and UAVs. This invention prints the open-circuit resonator on the surface of a dielectric substrate, allowing for integrated design with the antenna, significantly reducing design, manufacturing, and installation costs.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology and mainly relates to beam improvement of antenna radiation patterns. Specifically, it is a structure and method for achieving wide-bandwidth beam characteristics based on an open-loop resonator, which can be used for wide-bandwidth and wide-angle detection in radar. Background Technology

[0002] Currently, the development of radar detection technology has placed higher demands on range and angular resolution, thus requiring radar to acquire a larger information capacity during detection. Since the total amount of information transmitted per unit time is proportional to the signal bandwidth, expanding the signal bandwidth is a necessary choice to increase information capacity; therefore, it is necessary for radar systems to achieve broadband operation.

[0003] For radar to achieve effective positioning, it must be able to detect over a wide angle, requiring the antenna to operate within that area. Commonly used phased array radar technology is expensive and bulky, making it difficult to apply to small aircraft. For example, the compact space of UAVs requires radar systems to be as small and lightweight as possible. Vehicle-mounted radar also has strict requirements on the size and weight of the antenna. To balance wide-angle detection and miniaturization, wide-bandwidth beam antenna elements, such as dipole antennas and Vivaldi antennas, are often used in radar system design. The wide bandwidth characteristics of these antennas are well-suited for radar system design, but their inherent narrow beam characteristics often hinder wide-angle detection. Therefore, related beam spreading techniques have been proposed to improve system characteristics.

[0004] To address the issue of energy concentration in the main radiation direction of antennas, patent application CN107359410B, entitled "Novel Balanced Vivaldi Antenna Employing Additional Dielectric Layer Loading Technology and Hybrid Corrugated Edges," discloses a method for achieving high gain and a wide beam. This method, based on dielectric layer loading and novel corrugated edge loading, suppresses the antenna's back-radiated current, thereby improving gain to some extent. These structural loadings also broaden the beam to a certain degree. However, this method is highly dependent on the properties of the dielectric layer and is costly.

[0005] In existing technologies, low-cost methods for achieving wide beam characteristics typically involve loading elliptical parasitic structures or metamaterial structures between the tapered groove segments of a Vivaldi radar. For elliptical or quasi-elliptical parasitic structures, their primary function is direction-guiding, thereby reducing backradiation and increasing gain; their improvement on beamwidth is relatively limited. The amount of information acquired per unit time is directly proportional to the radar's operating bandwidth; therefore, bandwidth becomes a crucial indicator of radar system performance. For metamaterial structures, the narrow-band characteristics of the metamaterial itself make it difficult to achieve wide beam characteristics across a wide frequency range.

[0006] In summary, in the problem of antenna beam spreading, either the implementation cost is high or it is difficult to achieve beam spreading in a wide range. However, current radar systems need to achieve wide-bandwidth beam characteristics in a low-cost and compact space. Therefore, this invention aims to solve the above problems. Summary of the Invention

[0007] This invention addresses the deficiencies and problems in existing technologies by proposing a structure and method for achieving wide-bandwidth beam characteristics over a wide range under low-cost conditions, applicable to minicomputers and microcomputers, based on an open-loop resonant ring.

[0008] This invention relates to a structure for achieving wide-bandwidth beamforming of an antenna based on an aperture resonator. It includes an antenna and a parasitic structure loaded in the near-field radiation region in front of the antenna's radiating aperture. The parasitic structure is characterized by an aperture resonator array, which is composed of stacked aperture resonator subarrays of different frequency bands within the antenna's frequency band to achieve wide-bandwidth beamforming. The stacking arrangement follows a pattern where subarrays acting on higher frequency bands are closer to the antenna, and subarrays acting on lower frequency bands are farther away. Each aperture resonator subarray is formed by equidistant extension of aperture resonator units in both the lateral and longitudinal directions. The lateral extension spacing is less than three times the width of the aperture resonator, and the longitudinal extension spacing is less than three times the height of the aperture resonator. The aperture orientation of each aperture resonator unit is consistent. The aperture resonator array is printed on the surface of a dielectric substrate to form the parasitic structure that achieves wide-bandwidth beamforming of the antenna. The operating frequency bands of the subarrays are interconnected to form the operating frequency band of the loaded parasitic structure, which covers the antenna's operating frequency band. The number of subarrays does not exceed five.

[0009] This invention also provides a method for achieving wide-bandwidth beam characteristics based on an open-circuit resonator, implemented on any of the structures described in claims 1-3 for achieving wide-bandwidth beam characteristics of an antenna based on an open-circuit resonator, characterized by comprising the following steps:

[0010] (1) Design and form a structure based on an open-loop resonator to achieve wide-bandwidth beam characteristics: The designed parasitic structure is an open-loop resonator array, which is composed of stacked open-loop resonator subarrays of different frequency bands within the antenna band to achieve wide-bandwidth beam characteristics of the antenna; the stacking is performed according to the rule that the subarrays acting on higher frequency bands are closer to the antenna, and the subarrays acting on lower frequency bands are farther away from the antenna; each open-loop resonator subarray is formed by equidistant extension of open-loop resonator units in both the horizontal and vertical directions; the horizontal extension spacing is less than 3 times the width of the open-loop resonator, and the vertical extension spacing is less than 3 times the height of the open-loop resonator; the opening orientation of each open-loop resonator unit is consistent; the open-loop resonator array is printed on the surface of a dielectric substrate to form a parasitic structure that achieves wide-bandwidth beam characteristics of the antenna; the operating frequency bands of the subarrays are interconnected to form the working frequency band of the loaded parasitic structure, and the working frequency band of the loaded structure covers the working frequency band of the antenna; the number of subarrays does not exceed 5.

[0011] (2) Determine the number of subarrays and their operating frequency bands based on the antenna's operating frequency band: If the antenna's operating frequency band is narrow, set the number of subarrays to 1-2; if the antenna's operating frequency band is wide, set the number of subarrays to 3-5; divide the antenna frequency band according to the number of subarrays, with each subarray corresponding to a narrow frequency band.

[0012] (3) Stack and combine the subarrays to form an open resonant ring array arrangement: stack and combine the subarrays that act on the higher frequency band closer to the antenna and the subarrays that act on the lower frequency band further away from the antenna to form an open resonant ring array arrangement.

[0013] (4) Parasitic structure and antenna combination to form an antenna with wide bandwidth beam characteristics: The open resonant ring array is printed on the surface of the dielectric substrate according to the open resonant ring array arrangement scheme described in step (3), and the loaded parasitic structure is combined with the antenna to form an antenna with wide bandwidth beam characteristics.

[0014] (5) Achieving wide bandwidth beam characteristics: The loaded parasitic structure is located in the radiation near field region. When the antenna is working, the parasitic structure will generate a corresponding induced current and generate secondary radiation. The secondary radiation is superimposed with the radiation of the antenna itself. The antenna and the loaded resonant ring array as a whole form a wide beam radiation with a larger effective radiation angle domain than the original antenna, thus achieving wide bandwidth beam characteristics.

[0015] This invention also relates to the application of a structure and method for achieving wide-bandwidth beam characteristics of an antenna based on an open resonant ring, characterized by its application in environments with limited installation space, such as minicomputers and drones.

[0016] This invention utilizes a parasitic structure composed of open resonant rings to solve the technical problem of achieving compatibility between wide-bandwidth angular domain detection, compact structure, and low cost in radar detection processes.

[0017] Compared with the prior art, the technical advantages of the present invention are as follows:

[0018] A novel parasitic structure is proposed: In existing technologies, wide beamwidths are typically achieved through dielectric lens loading. This invention studies the radiation characteristics of split-ring resonators (SNRs). Utilizing their omnidirectional radiation properties, an SNR array is assembled and loaded in front of the antenna's radiating aperture. During antenna operation, the SNRs generate induced currents and secondary radiation, which, when superimposed on the antenna's own radiation field, broaden the antenna beamwidth. The SNR array proposed in this invention is lightweight and can be used in applications requiring low weight, such as lightweight aircraft.

[0019] Effectively extending the H-plane beamwidth of the antenna: This invention, through analysis of the antenna's working principle, concludes that to extend the antenna beamwidth by loading parasitic structures during radiation, the open-circuit resonator array should induce a strong current as much as possible in the near-field region. In this invention, the open-circuit resonator subarrays acting on higher frequency bands should be close to the antenna, while the open-circuit resonator arrays acting on lower frequency bands should be far from the antenna. This ensures that the open-circuit resonator arrays acting on all frequency bands can induce a sufficiently strong current, thereby generating strong secondary radiation. When superimposed with the original radiation field of the antenna, this significantly extends the H-plane beamwidth of the antenna.

[0020] Extending beamwidth over a wide bandwidth: This invention designs multiple open-loop resonant subarrays of different frequency bands and stacks them according to the rule that the subarrays acting on higher frequency bands are closer to the antenna, and the subarrays acting on lower frequency bands are farther away from the antenna. Compared with metamaterial loading structures, this invention utilizes the stacking combination of subarrays of multiple operating frequency bands and analyzes the superposition state of induced currents to precisely control the spacing between different subarrays, thereby achieving the technical objective of extending beamwidth over a wide bandwidth.

[0021] The design is flexible and easy to control: The parasitic structure proposed in this invention can be applied to various types of antennas, including but not limited to dipole antennas, Vivaldi antennas, and Yagi antennas. For different types of antennas, it is only necessary to design open-loop resonator arrays according to their operating frequency bands, and stack the open-loop resonator arrays acting on different frequency bands according to the rule that the parasitic arrays of the higher frequency band open-loop resonator arrays are closer to the antenna and the parasitic arrays of the lower frequency band open-loop resonator arrays are farther away from the antenna. Compared with dielectric lens loading, this invention has a more flexible and easier-to-control design.

[0022] It can be equipped in small and micro devices, is low-cost, and easy to be engineered: The present invention uses an open resonant ring array printed on a dielectric substrate as a parasitic structure, which widens the beamwidth of the antenna in a wide range. Compared with dielectric lenses, the present invention has lower cost and is easy to be engineered.

[0023] Currently, widely used drones require compact radar systems due to space constraints, necessitating miniaturization and weight. Vehicle-mounted radars also have stringent requirements regarding antenna size and weight. This invention loads a structure based on an open-loop resonant ring to achieve wide-bandwidth beam characteristics of the antenna within the near-field radiation region in front of the antenna's radiating aperture. This achieves the goal of wide-angle detection for the radar system within a small space, thus making it applicable to micro-devices. Attached Figure Description

[0024] Figure 1 Diagram of an open-loop resonant ring and its resonant current distribution;

[0025] Figure 2 The far-field radiation pattern when the open-ended resonant ring resonates;

[0026] Figure 3 This is a schematic diagram of the structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the operating frequency band of the parasitic structure loaded in this invention;

[0028] Figure 5 This is a flowchart of the method for achieving wide bandwidth beam characteristics based on an open resonant ring according to the present invention;

[0029] Figure 6 The left side is Figure 3 H-plane electric field diagram at 18 GHz with the central antenna unloaded by the open-loop resonator array. Figure 6 The right side is Figure 3 The H-plane electric field diagram at 18 GHz for an antenna-loaded open-loop resonator array is between Figure 6 The area between the left and right sides is the scale bar;

[0030] Figure 7 Comparison of the 6dB beamwidth of the antenna H-plane with and without the parasitic structure of this invention;

[0031] Figure 8 A comparison diagram showing the 6dB beamwidth of the antenna E-plane with and without the parasitic structure of this invention is provided. The invention will now be described in detail with reference to the accompanying drawings. Detailed implementation method:

[0032] Example 1

[0033] In the field of radar technology, since the total amount of information transmitted per unit time is directly proportional to the signal bandwidth, increasing information capacity and expanding the signal bandwidth are necessary choices, thus requiring radar systems to have wideband operating characteristics. However, while achieving broadband operation, it is even more important to achieve wide-angle domain detection to acquire more information. Current implementations are mostly based on phased arrays. However, phased array radars face many limitations in current applications, such as high manufacturing and installation costs, and large size and weight, which restrict their application in small unmanned aerial vehicles (UAVs). To address these current conditions and technical requirements, this invention proposes a structure and method for achieving wideband beam characteristics of an antenna based on an open-loop resonant ring. This can be used to solve the beam spreading problem of ultra-wideband antenna elements with narrow beamwidths.

[0034] This invention relates to a structure for achieving wide-bandwidth beam characteristics of an antenna based on an open-loop resonator. It includes an antenna and a parasitic structure loaded in the near-field region in front of the antenna's radiating aperture. See [link to relevant documentation]. Figure 3 , Figure 3 This is a schematic diagram of the structure of the present invention. The parasitic structure loaded in the present invention is an aperture resonant ring array. The aperture resonant ring array of the present invention is composed of stacked and combined aperture resonant ring subarrays of different frequency bands within the antenna frequency band. The secondary radiation field generated by the aperture resonant ring array when the antenna is working is superimposed with the radiation field of the antenna to achieve the wide bandwidth beam characteristics of the antenna. The loaded aperture resonant ring subarray is referred to as a subarray. The stacking and combination of the present invention is based on the rule that the subarrays acting on the higher frequency band are arranged closer to the antenna, and the subarrays acting on the lower frequency band are arranged further away from the antenna. Each aperture resonant ring subarray is formed by equidistant extension of aperture resonant ring units in both the horizontal and vertical directions. See [link to relevant documentation]. Figure 1 , Figure 1 This is a diagram of an open-loop resonant circuit and its resonant current distribution. When the open-loop resonant circuit resonates, the current exhibits a half-wavelength distribution, and the far-field pattern of the half-wavelength current shows omnidirectional characteristics. (See also...) Figure 2 , Figure 2 This is the far-field radiation pattern when the open-circuit resonator ring resonates. Figure 2 Composed of a Cartesian coordinate system and a spherical coordinate system overlaid with an open-circuit resonator structure and a far-field radiation pattern, this invention demonstrates the omnidirectional characteristics of the far-field radiation pattern of a half-wavelength ring current. This invention utilizes the omnidirectional radiation characteristics at resonance and uses open-circuit resonators as units to form an open-circuit resonator array. During antenna radiation, this array generates an induced current. The secondary radiation field of this induced current is superimposed on the antenna's radiation field, widening the antenna beamwidth and achieving wide-beam characteristics. The open-circuit resonator array of this invention is printed on the surface of a dielectric substrate and loaded in the near-field radiation region in front of the antenna's radiating aperture. Because the open-circuit resonator array in this invention uses dielectric substrate printing technology, it has a lighter weight and smaller volume, significantly reducing processing and installation costs compared to dielectric lens loading, and enabling beam extension functionality with low engineering costs.

[0035] The equidistant extension of the split-ring resonator unit in this invention satisfies the following conditions: the spacing during lateral extension is less than three times the width of the split-ring resonator, and the spacing during longitudinal extension is less than three times the height of the split-ring resonator. (See [reference needed]). Figure 3 Each open-loop resonator unit has a consistent opening orientation to ensure that the secondary radiation field does not cancel out due to current reversal. All open-loop resonator subarrays are printed on the surface of a dielectric substrate to form a parasitic structure that achieves the wide-bandwidth beam characteristics of the antenna. In this invention, the axis of the parasitic structure coincides with the antenna axis to ensure that the secondary radiation field does not change the direction of the main beam. Each subarray corresponds to a different frequency band, and the operating frequency bands of the subarrays are interconnected to form the operating frequency band of the loaded parasitic structure, which covers the antenna's operating frequency band. The number of subarrays does not exceed 5. If the antenna's operating frequency band is narrow, the number of subarrays is set to 2 or less, i.e., 1 or 2; if the antenna's operating frequency band is wide, the number of subarrays is set to 3-5.

[0036] This invention provides a novel parasitic structure applicable to ultra-wideband antenna elements. The Vivaldi antenna, due to its miniaturization and low cost, is currently the most commonly used ultra-wideband antenna element. However, its inherent drawback is a narrow beamwidth, particularly noticeable in the H-plane at high frequencies, thus preventing wide-angle detection in the H-plane. Existing technologies typically achieve wide beamwidths through dielectric lens loading. This invention studies the radiation characteristics of the split-ring resonator element and utilizes its omnidirectional radiation properties to form an split-ring resonator array, which is loaded in front of the antenna's radiating aperture. During antenna operation, the split-ring resonator array generates induced current and secondary radiation, which superimposes with the antenna's own radiation field, thus widening the antenna beamwidth. The split-ring resonator array proposed in this invention is lightweight and can be used in applications requiring low weight, such as lightweight aircraft.

[0037] Example 2

[0038] The structure for achieving wide-bandwidth beamforming of the antenna based on the open-loop resonator is the same as in Embodiment 1. However, the width of the parasitic structure formed by the stacked subarrays of this invention, i.e., the open-loop resonator array, must be substantially the same as the antenna width to ensure that the loaded parasitic structure is located within the main radiation direction of the near-field radiation region. See also... Figure 4 , Figure 4 This diagram illustrates the operating frequency band of the parasitic structure loaded in this invention. In this example, a combination of three sub-arrays operating at different frequency bands is used, with operating frequency bands of 10-12 GHz, 12-15 GHz, and 15-18 GHz, respectively, covering the 10-18 GHz band and coinciding with the antenna's operating frequency band. This invention has certain requirements regarding the distance between the sub-arrays of different frequency bands; see [link to documentation]. Figure 4In this invention, the distance between subarrays of different frequency bands within the parasitic structure is less than three times the height of the resonant ring unit; in this example, the spacing is 1.2 times the height of the resonant ring unit. The reason for controlling the distance between subarrays of different frequency bands to within three times the height of the open resonant ring is that the superposition of the secondary radiation fields of the induced current on each row of open resonant ring units has a positive effect on the expansion of the antenna beamwidth. If the distance between subarrays of different frequency bands is too large, the secondary radiation fields may cancel each other out or even degrade the antenna pattern.

[0039] This invention designs multiple open-loop resonant subarrays with different frequency bands. Compared to metamaterial-type loading structures, it utilizes the stacking combination of subarrays with multiple operating frequency bands and analyzes the superposition state of induced currents. By precisely controlling the spacing of different subarrays, it achieves the technical objective of extending beamwidth over a wide frequency range. The subarray stacking combination scheme adopted in this invention is easy to assemble and adjust, and is easy to operate in engineering implementation.

[0040] Example 3

[0041] The structure for achieving wide-bandwidth beamforming of the antenna based on the slotted resonator ring is the same as in Embodiments 1-2. However, the slotted resonator ring subarrays operating in different frequency bands must follow the principle that the parasitic array of the slotted resonator ring is closer to the antenna in higher frequency bands and farther away from the antenna in lower frequency bands. The subarrays for each frequency band are placed sequentially along the antenna radiation direction according to their operating frequency band, and the overall height of the slotted resonator ring array is not greater than the height of the antenna. See [link to documentation]. Figure 3 If the overall height of the open-loop resonant array is greater than the antenna height, the secondary radiation generated by the induced current intensity of the low-frequency subarray will not be sufficient to affect the antenna beamwidth because it is not located in the near-field region with high power density radiation.

[0042] This invention analyzes the working principle of the antenna and concludes that if a parasitic structure is to be added during radiation to expand the antenna beamwidth, the open-circuit resonator array should induce a strong current as much as possible in the near-field region. The open-circuit resonator subarrays acting on higher frequency bands should be close to the antenna, while the open-circuit resonator arrays acting on lower frequency bands should be far away from the antenna. This invention places the subarrays of each frequency band sequentially along the antenna radiation direction according to the frequency band of operation, ensuring that the open-circuit resonator subarrays acting on all frequency bands can induce a sufficiently strong current, generating strong secondary radiation. After being superimposed with the original radiation field of the antenna, the H-plane beamwidth of the antenna is significantly expanded.

[0043] Example 4

[0044] This invention also provides a method for achieving wide-bandwidth beam characteristics based on an open-circuit resonator, implemented on any of the aforementioned structures for achieving wide-bandwidth beam characteristics of antennas based on open-circuit resonators, see [link to relevant documentation]. Figure 5 , Figure 5The flowchart of the method for achieving wide bandwidth beam characteristics based on an open-circuit resonator according to the present invention includes the following steps:

[0045] (1) Design and formation of a structure based on open-loop resonators to achieve wide-bandwidth beam characteristics: The designed parasitic structure is an open-loop resonator array. The open-loop resonator array of this invention is composed of stacked open-loop resonator subarrays of different frequency bands within the antenna band. The loaded open-loop resonator subarray is referred to as a subarray to achieve wide-bandwidth beam characteristics of the antenna. The stacking combination of this invention is based on the rule that the subarrays acting on higher frequency bands are closer to the antenna, and the subarrays acting on lower frequency bands are farther away from the antenna. Each open-loop resonator subarray is formed by equidistant extension of open-loop resonator units in both the horizontal and vertical directions. The horizontal extension spacing of this invention is less than 3 times the width of the open-loop resonator, and the vertical extension spacing is less than 3 times the height of the open-loop resonator. The reason is that when the spacing of the open-loop resonators is too large, the generated secondary radiation field may degrade the antenna pattern, but it is necessary to ensure that there are a certain number of open-loop resonators in a compact space to generate a strong and dense induced current. The opening orientation of each open-loop resonator unit of this invention is consistent. The reason is that if the openings are inconsistent, the secondary radiation field of the induced current may cancel out or even degrade the antenna pattern to a certain extent. The open-loop resonator array of this invention is printed on the surface of a dielectric substrate to form a parasitic structure that realizes the wide bandwidth beam characteristics of the antenna. The axis of the parasitic structure coincides with the antenna axis. Each subarray of this invention corresponds to a different frequency band, and the operating frequency bands of the subarrays are interconnected to form the operating frequency band of the loaded parasitic structure. The operating frequency band of the loaded structure covers the antenna's operating frequency band. To ensure that all subarrays are within the antenna's near-field radiation region, the number of subarrays does not exceed five.

[0046] (2) Determine the number of subarrays and their operating frequency bands based on the antenna's operating frequency band: If the antenna's operating frequency band is narrow, the number of subarrays can be set to no more than 2. If the antenna's operating frequency band is wide, the number of subarrays can be set to 3-5. Divide the antenna frequency band equally according to the number of subarrays. Each subarray corresponds to a narrow frequency band in the antenna's operating frequency band, and it plays the role of extending the beam within this narrow frequency band.

[0047] (3) Stack and combine the subarrays to form an open resonant ring array arrangement: Stack and combine the subarrays that act on the higher frequency band closer to the antenna and the subarrays that act on the lower frequency band further away from the antenna to form an open resonant ring array arrangement.

[0048] (4) Parasitic structure and antenna combination to form an antenna with wide bandwidth beam characteristics: The open resonant ring array is printed on the surface of the dielectric substrate according to the open resonant ring array arrangement scheme described in step (3), and the loaded parasitic structure is combined with the antenna to form an antenna with wide bandwidth beam characteristics. When combining, it is necessary to ensure that the axis of the open resonant ring array coincides with the axis of the antenna.

[0049] The parasitic structure of the present invention is combined with an antenna to form an antenna with wide bandwidth beam characteristics, or printed on the surface of a dielectric substrate according to an open resonant ring arrangement scheme to form a loaded parasitic structure as a whole, and the loaded parasitic structure is installed in the main radiation direction of the antenna radiation near field region, or the open resonant ring array and the antenna are integrated and printed on the dielectric substrate.

[0050] (5) Achieving wide-bandwidth beam characteristics: The loaded parasitic structure is located in the near-field radiation region. The distance between the loaded parasitic structure and the antenna must ensure that it induces a strong current as much as possible, while not affecting the antenna's original radiation current due to excessive distance. When the antenna is working, the parasitic structure of this invention generates secondary radiation through induced current. The secondary radiation is superimposed on the antenna's own radiation, and the antenna and the loaded resonant ring array as a whole form a wide-bandwidth beam radiation with an effective radiation angle greater than that of the original antenna, increasing the beamwidth of the antenna pattern and achieving wide-bandwidth beam characteristics.

[0051] The parasitic structure proposed in this invention can be applied to various types of antennas, including but not limited to dipole antennas, Vivaldi antennas, and Yagi antennas. Among these, the Vivaldi antenna, due to its miniaturization and low cost, has become the most commonly used ultra-wideband antenna element. However, its inherent drawback is a narrow beamwidth, which is particularly pronounced in the H-plane at high frequencies, thus preventing wide-angle detection in the H-plane. The parasitic structure proposed in this invention can extend its H-plane beamwidth. For different types of antennas, this invention only requires designing open-loop resonator arrays according to their operating frequency bands. The open-loop resonator arrays acting on different frequency bands are stacked according to the rule that the parasitic array of the higher-frequency open-loop resonator is closer to the antenna, and the parasitic array of the lower-frequency open-loop resonator is farther away from the antenna. Compared to dielectric lens loading, this invention offers a more flexible and controllable design and fabrication scheme.

[0052] Example 5

[0053] The structure and method for achieving wide-bandwidth beam characteristics based on the open-loop resonator are the same as in Examples 1-4. The parasitic structure described in step (4) is combined with the antenna to form an antenna with wide-bandwidth beam characteristics, including the following steps:

[0054] 4.1 Antennas with wide-bandwidth beam characteristics are discrete structures: When the antenna is a planar structure but its E-plane is not coplanar with the open resonant ring array or the antenna is not a planar structure, the loading structure is installed in the near-field radiation region of the antenna through relevant fixing devices.

[0055] 4.2 Antennas with wide-bandwidth beam characteristics are integrated structures: When the antenna is a planar structure and its E-plane is coplanar with the open resonant ring array, the loading structure and the antenna are directly printed on the same dielectric substrate surface for integrated design and processing.

[0056] This invention combines a parasitic structure with an antenna to form an antenna with wide-bandwidth beam characteristics. The combination method is not unique. When the antenna is planar but its E-plane is not coplanar with the open-circuit resonator array, or when the antenna is not planar, the loading structure is installed in the near-field radiation region of the antenna using a relevant fixing device. The fixing device should be an insulator with a low dielectric constant; using metal or a high dielectric constant insulator will affect the antenna's radiation. When the antenna is planar and its E-plane is coplanar with the open-circuit resonator array, the loading structure and antenna are directly printed on the same dielectric substrate surface for integrated design and fabrication. This method can be widely applied to beam spreading problems in tapered slot antennas.

[0057] Example 6

[0058] This invention also relates to the application of a structure and method for achieving wide-bandwidth beam characteristics of an antenna based on an open-loop resonator. The structure and method for achieving wide-bandwidth beam characteristics of an antenna based on an open-loop resonator are the same as in Examples 1-5. This invention is applicable to environments with limited installation space, such as minicomputers and drones.

[0059] The parasitic loading structure proposed in this invention uses an open-loop resonator as the basic unit. This basic unit is extended equidistantly in both the horizontal and vertical directions to form an open-loop resonator subarray. Subarrays of different frequency bands are stacked and combined to form a complete loading structure. This structure is lightweight and miniaturized, making it suitable for environments with tight space constraints, such as minicomputers and drones. The proposed parasitic loading structure is an open-loop resonator array printed on the surface of a dielectric substrate, significantly reducing processing costs and possessing broad engineering application value. When combined with an antenna, the proposed parasitic loading structure is small in size, lightweight, easy to operate, and applicable to a wide range of environments.

[0060] Example 7

[0061] The structure and method for achieving wide-bandwidth beam characteristics of an antenna based on an open-loop resonator are the same as in Examples 1-6.

[0062] This invention primarily addresses the problem of excessively narrow high-frequency H-plane beamwidth in current ultra-wideband Vivaldi antennas. See also... Figures 1-2This demonstrates the omnidirectional characteristics of the far-field radiation pattern of the open-loop resonator unit. (See also...) Figure 3 An array of split-ring resonators is placed in front of the radiating aperture of a conventional Vivaldi antenna operating in the 10-18 GHz frequency band. The Vivaldi antenna in this invention can be replaced with any antenna that generates broadband radiation within a finite aperture. This invention utilizes the omnidirectional radiation characteristics of split-ring resonators, leveraging the superposition of induced current radiation and antenna radiation when the split-ring resonator array acts as a secondary radiation source to improve the beamwidth of the radiation pattern. See also... Figure 4 Different frequency bands of the split-ring resonator subarrays are designed separately and stacked according to the rule that the higher frequency band split-ring resonator subarrays are closer to the antenna and the lower frequency band split-ring resonator subarrays are farther away from the antenna, so that there is a corresponding structure for beam broadening when electromagnetic wave radiation occurs in different frequency bands. In this example, the split-ring resonator used is square, and the wide beam characteristic is achieved by utilizing the omnidirectional characteristics of the far-field radiation pattern of the split-ring resonator. Therefore, the purpose of the invention can still be achieved when the split-ring resonator is circular.

[0063] This invention uses an array of split-ring resonators printed on a dielectric substrate as a parasitic structure, which broadens the antenna beamwidth over a wide bandwidth. Compared to dielectric lenses, this invention has lower cost and is easier to engineer. The dielectric constant of the dielectric substrate can be compromised between miniaturization and bandwidth requirements. When high miniaturization is required, a high-dielectric-constant substrate, such as FR4, can be used. When the antenna bandwidth is wide, each split-ring resonator subarray needs to have a wide bandwidth, in which case a low-dielectric-constant substrate, such as Rogers 5880, should be considered.

[0064] This invention loads a structure based on an open resonant ring to achieve wide-bandwidth beam characteristics of an antenna into the radiation near-field region in front of the antenna's radiation aperture. If the parasitic structure is too close to the antenna, it will be located in the induction near-field region. Since the induction near-field region is an energy storage field, the parasitic structure located in the induction near-field region will have a significant impact on the antenna's impedance characteristics and current distribution, thus deteriorating the antenna's radiation pattern.

[0065] This invention achieves the goal of wide-angle detection in a compact space, providing an effective solution for miniaturization of detection equipment.

[0066] This invention presents a structure and method for achieving wide-bandwidth beamwidth characteristics based on an open-circuit resonator, solving the problem of balancing wide-bandwidth angular domain detection, compact structure, and low cost in radar detection. Utilizing the omnidirectional radiation characteristics of the open-circuit resonator during resonance, the invention extends the open-circuit resonator at equal intervals to form an open-circuit resonator subarray. Subarrays corresponding to different frequency bands are combined into an open-circuit resonator array, which is then loaded into the near-field radiation region in front of the antenna's radiating aperture. During antenna operation, the open-circuit resonators generate induced currents, and the radiation field of these induced currents superimposes with the antenna's radiation field, significantly extending the antenna's beamwidth over a wide bandwidth. The open-circuit resonator units are small in size, allowing for a sufficient number of units to be contained within a small space after arraying. This invention achieves beam extension functionality in a compact space, exhibiting miniaturization characteristics, and can be applied to small aircraft and UAVs. Furthermore, by printing the open-circuit resonator on the surface of a dielectric substrate, it can be integrated with the antenna design, significantly reducing design, manufacturing, and installation costs. This invention provides a method for achieving wide-bandwidth beam characteristics based on an open-circuit resonator. The steps include: (1) designing and forming a structure based on an open-circuit resonator to achieve wide-bandwidth beam characteristics; (2) determining the number of subarrays and their operating frequency bands according to the antenna's operating frequency band; (3) stacking and combining the subarrays to form a parasitic loading structure; and (4) achieving wide-bandwidth beam characteristics. This invention is compact, low-cost, and can achieve wide-bandwidth beam characteristics over a wide range, making it applicable to broadband radar systems with wide-angle detection requirements.

[0067] The technical effects of this invention will be further explained below with reference to simulation:

[0068] Example 8

[0069] The structure and method for achieving wide-bandwidth beam characteristics based on the open resonant ring are the same as in Examples 1-7. Simulation conditions: ANSYS HFSS version 19.2 is used for simulation.

[0070] Simulation content: The electric field amplitude of the H-plane at 18 GHz with and without the structure of this invention loaded; simulation results are shown below. Figure 6 .

[0071] Simulation results and analysis: See Figure 6 , Figure 6 The left side is Figure 3 H-plane electric field diagram at 18 GHz with the central antenna unloaded by the open-loop resonator array. Figure 6 The right side is Figure 3 The H-plane electric field diagram at 18 GHz for an antenna-loaded open-loop resonator array is between Figure 6 The area between the left and right sides is the scale bar. See also Figure 6 On the left, the electric field is mainly concentrated in a narrow angular region, while Figure 6On the right side, due to the secondary radiation from the parasitic structure, compared to Figure 6 On the left, the electric field is more dispersed, resulting in a wider beamwidth in the far-field pattern. (Compare) Figure 6 As can be seen from the left and right sides, the electric field after loading the parasitic structure in this invention exhibits a wide beam characteristic, significantly expanding the beamwidth of the H-plane.

[0072] Example 9

[0073] The structure and method for achieving wide-bandwidth beam characteristics based on the open-loop resonator are the same as in Examples 1-7, and the simulation conditions are the same as in Example 8.

[0074] Simulation content: H-plane 6dB beamwidth with and without loading of the structure of this invention; simulation results are available in [reference needed]. Figure 7 Simulation results and analysis: See [link / reference] Figure 7 , Figure 7 A comparison diagram of the 6dB beamwidth of the H-plane of the antenna with and without the parasitic structure of this invention. Figure 7 The horizontal axis represents frequency, and the vertical axis represents 6dB beamwidth. The triangles in the figure represent the 6dB beamwidth with the structure of this invention applied, while the squares represent the 6dB beamwidth without the structure of this invention applied. It can be seen that this invention contributes to beamwidth broadening across the entire frequency band, with a maximum improvement of 50°, significantly extending the H-plane beamwidth.

[0075] Example 10

[0076] The structure and method for achieving wide-bandwidth beam characteristics based on the open-loop resonator are the same as in Examples 1-7, and the simulation conditions are the same as in Example 8.

[0077] Simulation content: 6dB beamwidth in the E-plane with and without loading of the structure of this invention; simulation results are available in [reference needed]. Figure 8 Simulation results and analysis: See [link / reference] Figure 8 , Figure 8 A comparison diagram of the 6dB beamwidth of the antenna E-plane with and without the parasitic structure of this invention. Figure 8 The horizontal axis represents frequency, and the vertical axis represents 6dB beamwidth. In the figure, triangles represent the 6dB beamwidth with the structure of this invention applied, and squares represent the 6dB beamwidth without the structure of this invention applied. It can be seen that in the low-frequency band, this invention does not change the beamwidth of the E-plane; in the high-frequency band, this invention significantly improves the E-plane beamwidth, with a maximum improvement of 40°, achieving the purpose of the invention and expanding the beamwidth of the E-plane.

[0078] In summary, the present invention provides a structure and method for achieving wide-bandwidth beam characteristics based on an open-ended resonant ring. This solves the technical problem of achieving compatibility between wide-bandwidth angular domain detection, compact structure, and low cost in radar detection. The key is to utilize the omnidirectional radiation characteristics of the open-ended resonant ring to achieve wide-bandwidth beam characteristics under low-cost conditions, and it can be applied to minicomputers and microcomputers.

[0079] The loaded parasitic structure is an aperture resonant ring array, which is composed of stacked aperture resonant ring subarrays of different frequency bands within the antenna band. Higher frequency subarrays are closer to the antenna, and lower frequency subarrays are further away. The operating frequency bands of the subarrays are interconnected to form the operating frequency band of the loaded parasitic structure, which covers the antenna's operating frequency band. This invention provides a method for achieving wide-bandwidth beam characteristics based on aperture resonant rings. This method includes: designing an aperture resonant ring structure to achieve wide-bandwidth beam characteristics; determining the number and operating frequency bands of the subarrays according to the antenna's operating frequency band; stacking and combining the subarrays to form an overall aperture resonant ring array arrangement; combining the parasitic structure with the antenna to form an antenna with wide-bandwidth beam characteristics; and achieving wide-bandwidth beam characteristics. This invention utilizes the omnidirectional radiation characteristics of an open-circuit resonator (OCR) at resonance. The OCR is equidistantly extended to form an OCR subarray, and subarrays corresponding to different frequency bands are combined into an OCR array. This OCR array is then placed in the near-field radiation region in front of the antenna's radiating aperture. When the antenna operates, the OCR generates an induced current, and the radiation field of this induced current is superimposed on the antenna's radiation field, significantly extending the antenna's beamwidth over a wide bandwidth. The OCR elements are relatively small, allowing for a sufficient number of OCR elements to be contained within a small space after arraying. This invention achieves beam extension in a compact space, exhibiting miniaturization characteristics, and can be applied to small computers and drones. Furthermore, by printing the OCR onto the surface of a dielectric substrate, this invention allows for integrated design with the antenna, significantly reducing design, manufacturing, and installation costs.

Claims

1. A structure for realizing wideband beam characteristics of an antenna based on open resonant loop, comprising an antenna and a parasitic structure loaded in the radiation near-field region in front of the antenna radiation aperture, characterized in that, The parasitic structure is an aperture resonant ring array, which is composed of stacked aperture resonant ring subarrays of different frequency bands within the antenna band to achieve wide-bandwidth beamforming characteristics of the antenna. The stacking is arranged such that subarrays acting on higher frequency bands are closer to the antenna, and subarrays acting on lower frequency bands are farther away from the antenna. Each aperture resonant ring subarray is formed by equidistant extension of aperture resonant ring units in both the horizontal and vertical directions. The horizontal equidistant extension spacing is less than 3 times the width of the aperture resonant ring, and the vertical equidistant extension spacing is less than 3 times the height of the aperture resonant ring. The aperture orientation of each aperture resonant ring unit is consistent. The aperture resonant ring array is printed on the surface of a dielectric substrate to form a parasitic structure that achieves wide-bandwidth beamforming characteristics of the antenna. The operating frequency bands of the subarrays are interconnected to form the operating frequency band of the parasitic structure, which covers the antenna's operating frequency band. The number of subarrays does not exceed 5. The width of the parasitic structure formed by the stacking of subarrays must be basically consistent with the width of the antenna to ensure that the loaded parasitic structure is located in the main radiation direction of the near-field radiation region; the distance between subarrays of different frequency bands within the parasitic structure is less than 3 times the height of the resonant ring unit.

2. The structure for implementing antenna wideband beam characteristics based on open resonant ring according to claim 1, characterized in that, Each frequency band subarray is placed sequentially along the antenna radiation direction according to the frequency band of operation, and the overall height of the open resonant ring array is not greater than the height of the antenna.

3. A method for achieving wide-bandwidth beam characteristics based on an open-circuit resonator, implemented on the structure for achieving wide-bandwidth beam characteristics of an antenna based on an open-circuit resonator as described in any one of claims 1-2, characterized in that, The steps include the following: (1) Design and form a structure based on an open-loop resonator to achieve wide-bandwidth beam characteristics: The designed parasitic structure is an open-loop resonator array, which is composed of stacked open-loop resonator subarrays of different frequency bands within the antenna band to achieve wide-bandwidth beam characteristics of the antenna; the stacking is performed according to the rule that the subarrays acting on higher frequency bands are closer to the antenna, and the subarrays acting on lower frequency bands are farther away from the antenna; each open-loop resonator subarray is formed by equidistant extension of open-loop resonator units in both the horizontal and vertical directions; the horizontal extension spacing is less than 3 times the width of the open-loop resonator, and the vertical extension spacing is less than 3 times the height of the open-loop resonator; the opening orientation of each open-loop resonator unit is consistent; the open-loop resonator array is printed on the surface of a dielectric substrate to form a parasitic structure that achieves wide-bandwidth beam characteristics of the antenna; the operating frequency bands of the subarrays are interconnected to form the working frequency band of the loaded parasitic structure, and the working frequency band of the loaded structure covers the working frequency band of the antenna; the number of subarrays does not exceed 5. (2) Determine the number of subarrays and their operating frequency bands according to the antenna's operating frequency band: If the antenna's operating frequency band is narrow, set the number of subarrays to 1-2; if the antenna's operating frequency band is wide, set the number of subarrays to 3-5; divide the antenna frequency band according to the number of subarrays, with each subarray corresponding to a narrow frequency band; (3) Stack and combine the subarrays to form an open resonant ring array arrangement: stack and combine the subarrays that act on the higher frequency band closer to the antenna and the subarrays that act on the lower frequency band further away from the antenna to form an open resonant ring array arrangement. (4) Parasitic structure and antenna combination to form an antenna with wide bandwidth beam characteristics: The open resonant ring array is printed on the surface of the dielectric substrate according to the open resonant ring array arrangement scheme described in step (3), and the loaded parasitic structure is combined with the antenna to form an antenna with wide bandwidth beam characteristics. (5) Achieving wide bandwidth beam characteristics: The loaded parasitic structure is located in the radiation near field region. When the antenna is working, the parasitic structure will generate a corresponding induced current and generate secondary radiation. The secondary radiation is superimposed with the radiation of the antenna itself. The antenna and the loaded resonant ring array as a whole form a wide beam radiation with a larger effective radiation angle domain than the original antenna, thus achieving wide bandwidth beam characteristics.

4. The method for achieving wide bandwidth beam characteristics based on an open-circuit resonator according to claim 3, characterized in that, The parasitic structure described in step (4) is combined with the antenna to form an antenna with wide-bandwidth beam characteristics, including the following steps: 4.1 Antennas with wide-bandwidth beam characteristics are discrete structures: When the antenna is a planar structure but its E-plane is not coplanar with the open resonant ring array or the antenna is not a planar structure, the loading structure is installed in the near-field radiation region of the antenna through relevant fixing devices; 4.2 Antennas with wide-bandwidth beam characteristics are integrated structures: When the antenna is a planar structure and its E-plane is coplanar with the open resonant ring array, the loading structure and the antenna are directly printed on the same dielectric substrate surface for integrated design and processing.

5. An application of the structure for achieving wide-bandwidth beam characteristics of an antenna based on an open-loop resonator as described in claim 1, characterized in that, The structure based on the open resonant ring to achieve wide-bandwidth beam characteristics of the antenna can be applied in environments with limited installation space, and can be used for small computers and drones.

6. An application of the method for achieving wide bandwidth beam characteristics of an antenna based on an open-loop resonator as described in claim 3, characterized in that, The structure based on the open resonant ring to achieve wide-bandwidth beam characteristics of the antenna can be applied in environments with limited installation space, and can be used for small computers and drones.

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