A design method and structure of a half-mode dielectric ridge parallel plate waveguide double-beam wide-angle scanning leaky-wave antenna based on a PCB process

Abstract

This invention discloses a design method and structure for a half-mode dielectric ridge parallel plate waveguide dual-beam wide-angle scanning leaky antenna based on PCB technology. Manufactured using a fully printed circuit board process, it includes a core structure of a half-mode dielectric ridge parallel plate waveguide transmission line formed by laminating three dielectric substrates, a metallized via array disposed at the edge of the waveguide's non-radiating open aperture to suppress energy leakage, and a periodic dipole array symmetrically arranged on the radiating open aperture side of the waveguide. This invention solves the technical problems of high manufacturing cost, narrow scanning range, and difficulty in implementing dual beams in traditional leaky antennas, providing a low-cost, high-performance, and easily integrated antenna solution.

Description

Technical Field

[0001] This invention belongs to the field of microwave and millimeter-wave antenna technology, specifically relating to a design method and structure of a half-mode dielectric ridge parallel plate waveguide dual-beam wide-angle scanning leaky wave antenna based on PCB (printed circuit board) technology. Background Technology

[0002] Leaky-wave antennas (LWAs) have gained widespread attention in the microwave and millimeter-wave fields in recent years due to their simple structure, inherent frequency scanning characteristics, and high directivity, demonstrating significant application potential. With the development of 5G and future 6G mobile communications, automotive radar, and imaging systems, there is an urgent need for millimeter-wave antennas with high gain, low profile, low cost, and high integration with millimeter-wave circuits. LWAs can achieve beam scanning by changing the operating frequency without the need for complex phased array feed networks, perfectly meeting these requirements.

[0003] Traditional LWA designs often focus on excitation of the fundamental mode or a single spatial harmonic to achieve stable single-beam radiation. However, with the increasing demands of modern wireless systems for multi-functional and multi-target coverage, multi-beam antennas capable of flexibly covering multiple targets or areas in different directions have become an important research direction for high-performance LWA design. In particular, in dual-target interaction scenarios such as millimeter-wave full-duplex communication and radar dual-target detection and tracking, the design of dual-beam LWAs with synchronous spatial coverage capabilities has become a critical requirement.

[0004] To meet this need, researchers have proposed various methods for implementing dual-beam wide-angle scanning (LWA). However, these existing methods typically require complex feed network designs or multi-element arrays, leading to complex antenna structures, increased losses, and difficulty in maintaining high-efficiency, high-gain radiation performance over a wide bandwidth. Therefore, exploring a simple, high-performance dual-beam wide-angle scanning LWA based on standard PCB technology has significant practical implications and application value.

[0005] In PCB-based LWA designs, various transmission line structures have been explored, such as microstrip lines, substrate integrated waveguides (SIW), substrate integrated coaxial lines (SICL), and spoof surface plasmon polaritons (SSPPs). Among these, the periodic leaky wave antenna based on the traditional dielectric ridge parallel-plate waveguide (DRPW) or half-mode dielectric ridge parallel-plate waveguide (HMDRPW) structure is most similar to this invention.

[0006] A typical implementation scheme is the design of a leaky wave antenna (LWA) and its array based on a diffused pulse wave (DRPW). This type of antenna typically consists of two parallel metal plates and an embedded dielectric ridge forming the main waveguide structure. Energy is confined within the dielectric ridge and propagates along it, while the upper and lower metal plates constitute the height boundary. Notably, in this traditional DRPW structure, the upper and lower metal layers are typically machined using CNC precision machining, while the dielectric ridge in the middle is fabricated using PCB technology. These two fabrication methods together constitute the basic transmission line structure of the DRPW. To generate radiation, periodic slots are etched on the upper metal plate of the DRPW, enabling single-beam scanning. As a further development, existing technologies have also disclosed leaky wave antennas and their array structures based on high-density magnetic field (HMDRPW). HMDRPW is a novel transmission line structure with miniaturization potential, obtained by cutting a DRPW in half along the electric field symmetry plane. It aims to further reduce the structural size while maintaining the original full-mode transmission characteristics. Therefore, the traditional fabrication method for HMDRPW is consistent with that of DRPW, requiring a combination of CNC metal machining and PCB fabrication. In addition, some studies have used dipole arrays fed by half-mode substrate integrated waveguides (HMSIW) to achieve broadband end-fire radiation, but such designs mainly achieve fixed-beam end-fire rather than frequency scanning performance.

[0007] Currently, although the closest existing technical solutions have demonstrated good performance potential and can achieve frequency scanning or fixed end-fire radiation, they still have certain limitations in realizing low-cost, high-performance dual-beam scanning systems for microwave and millimeter-wave applications. First, the closest existing solution relies on a hybrid manufacturing process combining PCB fabrication and CNC metalworking for its core transmission line structure. This non-full PCB manufacturing method not only increases assembly steps and alignment difficulties but also directly leads to increased manufacturing costs and decreased production efficiency, making it difficult to meet the stringent cost control requirements of large-scale commercial applications. Furthermore, its integration with planar circuits is less convenient, making it difficult to build highly integrated RF front-end modules. Second, existing designs cannot achieve continuous, large-angle scanning from end-fire to side-fire, limiting their spatial coverage. Simultaneously, existing structures face design difficulties in achieving stable, symmetrical, high-performance dual beams. Finally, to achieve vertically symmetrical dual beams, traditional structures often require simultaneously etching perfectly symmetrical radiation slots or setting other radiation units on the upper and lower walls of the waveguide. In actual PCB fabrication, this demands extremely high multilayer alignment accuracy; any deviation will disrupt the symmetry of the dual beams. Furthermore, this symmetrical structure may excite unwanted modes, interfering with antenna performance and leading to decreased gain and increased sidelobe levels.

[0008] It is particularly noteworthy that achieving stable, high-performance LWA dual-beam radiation is inherently challenging in existing technologies. For traditional waveguide structures (such as SIW and DRPW), theoretically, obtaining symmetrical dual beams requires simultaneously etching perfectly symmetrical radiating elements (such as slots) on both the upper and lower metal walls of the waveguide. However, this tight symmetrical excitation can, in some cases, induce unwanted parasitic modes, interfering with the radiation of the dominant mode, leading to decreased gain, increased sidelobe levels, and degraded efficiency. On the other hand, academia has also explored designs based on single-conductor transmission lines without a ground plane (such as high-fidelity lines and SSPPs structures) to naturally generate dual beams. These structures, lacking the influence of a ground plane, exhibit a symmetrical radiation field distribution on both sides. However, these open structures often face challenges such as the generation of other stray modes (such as parasitic modes and surface wave modes), susceptibility to installation environment interference, and limited power capacity, thus limiting their application in scenarios with high requirements for isolation and environmental stability.

[0009] In summary, existing technologies struggle to achieve a balance between antenna manufacturability (low cost, full PCB manufacturing process) and radiation performance (wide-angle dual-beam scanning, wide bandwidth, and high efficiency). Therefore, the industry urgently needs an innovative antenna structure that provides an integrated solution to both manufacturing and performance challenges. Summary of the Invention

[0010] In view of the shortcomings of the prior art, the present invention aims to address the following: (1) A leaky antenna structure based entirely on standard PCB technology is provided to achieve high performance with low-cost processing, simplify the production process, and improve the integration with planar circuits.

[0011] (2) A leaky antenna structure that can achieve wide-angle frequency scanning of dual beams in a wide frequency band is provided. The core purpose is to enable the scanning range of a single beam to cover the vicinity of the end-fire direction to the side-fire direction, so as to break through the bottleneck of insufficient scanning angle of the existing technology, and to form symmetrical dual beams that together cover a super half-space angular domain of nearly 190°.

[0012] (3) A high-performance dual-beam antenna design scheme with stable structure and easy processing is provided. Its radiation element and waveguide structure have high integration. It aims to achieve stable and symmetrical dual beams in the ultra-wide working bandwidth and maintain high and stable radiation efficiency in the entire scanning bandwidth.

[0013] In a first aspect, the present invention provides a design method for a dual-beam wide-angle scanning leaky antenna of a half-mode dielectric ridge parallel plate waveguide based on PCB technology, comprising the following steps: S1. Design and construct the core structure of a half-mode dielectric ridge parallel plate waveguide transmission line based on full PCB technology; S2. A leakage suppression structure is designed at the non-radiative open aperture edge of the half-mode dielectric ridge parallel plate waveguide to suppress energy leakage. S3. Based on the dispersion characteristics of the half-mode dielectric ridge parallel plate waveguide and the spatial harmonic theory, a periodic radiating element is designed on the radiating open aperture side of the waveguide.

[0014] Based on the above scheme, step S1 specifically includes the following steps: Theoretical analysis of the electromagnetic propagation characteristics of HMDRPW: The phase constant β of a conventional DRPW operating in quasi-TEM mode with zero cutoff frequency is given by the following expression: ; Where εr is the relative permittivity of the dielectric ridge in the DRPW, k0 is the wave number in vacuum, and βy is the transverse phase constant of the DRPW. The value of βy is obtained by solving the following transcendental equation: ; Where td is the width of the medium ridge in DRPW; A compensation coefficient γ related to the dielectric properties of the dielectric ridge is introduced, and the expression for the corrected phase constant βHM is established as follows: ; Where t0 is the width of the medium ridge in HMDRPW; The upper, middle and lower dielectric substrates are laminated together to form a single unit; In this structure, the middle dielectric substrate forms the dielectric ridge of the waveguide; the bottom of the upper dielectric substrate is coated with copper to form the upper metal boundary, and the top of the lower dielectric substrate is coated with copper to form the lower metal boundary. These two metal boundaries correspond to the upper and lower metal plates in the traditional HMDRPW structure, respectively. The upper and lower metal boundaries and the dielectric ridge together form the core transmission line of the HMDRPW, thereby forming the half-mode dielectric ridge parallel plate waveguide.

[0015] Based on the above scheme, step S2 specifically includes the following steps: At the open aperture on the other side of the waveguide where it does not participate in radiation, the upper and lower dielectric substrates are simultaneously extended outward by a specific width to form an extension region; Two rows of closely spaced and symmetrically distributed metallized via arrays are provided at the copper foil boundary of the extended region. The metallized via arrays penetrate the dielectric substrate to form an electromagnetic shielding boundary and suppress the lateral leakage of electromagnetic energy from the non-radiative side.

[0016] Based on the above scheme, step S3 specifically includes the following steps: A periodic dipole array is symmetrically arranged on the upper and lower dielectric substrates on the radiating open aperture side of the half-mode dielectric ridge parallel plate waveguide. The condition under which the -1st spatial harmonic can radiate outward is: ; in, λ 0 represents the wavelength in a vacuum. p d The arrangement period of the dipoles, its beam pointing angle θ It is determined by the following formula: .

[0017] Secondly, a half-mode dielectric ridge parallel plate waveguide dual-beam wide-angle scanning leaky antenna structure based on PCB technology is provided, including: Core structure of half-mode dielectric ridge parallel plate waveguide transmission line based on full PCB process; The leakage suppression structure at the non-radiative open aperture edge of the half-mode dielectric ridge parallel plate waveguide is used to suppress energy leakage; Based on the dispersion characteristics of the half-mode dielectric ridge parallel plate waveguide and the spatial harmonic theory, a periodic radiating element is formed on the radiating open aperture side of the waveguide.

[0018] Based on the above scheme, the core structure of the half-mode dielectric ridge parallel plate waveguide transmission line includes: The upper dielectric substrate has a copper-clad bottom layer forming an upper metal boundary; The middle dielectric substrate forms the dielectric ridge of the waveguide; The lower dielectric substrate has a copper-clad top layer forming a lower metal boundary. The upper metal boundary and the lower metal boundary correspond to the upper and lower metal plates in the traditional HMDRPW structure, respectively; the upper metal boundary and the lower metal boundary together with the dielectric ridge constitute the core transmission line of HMDRPW, thereby forming the half-mode dielectric ridge parallel plate waveguide. The upper, middle and lower dielectric substrates are integrally formed by PCB lamination process.

[0019] Based on the above scheme, the leakage suppression structure includes: At the open aperture on the other side of the waveguide where it does not participate in radiation, the upper dielectric substrate and the lower dielectric substrate extend outward synchronously to form an extension region of a specific width. Two rows of closely spaced and symmetrically distributed metallized via arrays are located at the copper foil boundary of the extended region. The metallized via arrays penetrate the dielectric substrate to form an electromagnetic shielding boundary, suppressing the lateral leakage of electromagnetic energy from the non-radiative side.

[0020] Based on the above scheme, the periodic radiation unit includes: A periodic dipole array symmetrically arranged on the upper and lower dielectric substrates on the radiating open aperture side of the half-mode dielectric ridge parallel plate waveguide. The condition under which the -1st spatial harmonic can radiate outward is: ; in, λ 0 represents the wavelength in a vacuum. p d The arrangement period of the dipoles, its beam pointing angle θ It is determined by the following formula: .

[0021] The beneficial effects of this invention are: This invention proposes a design method and structure for a half-mode dielectric ridge parallel plate waveguide dual-beam wide-angle scanning leaky antenna based on a fully printed circuit board (PCB) process. This structure achieves high-performance dual-beam radiation through the following innovative designs: First, the half-mode dielectric ridge parallel plate waveguide transmission line is implemented using a full PCB process, replacing the traditional hybrid processing method with a three-layer dielectric substrate lamination structure, significantly reducing manufacturing costs and improving integration. Second, an innovative edge leakage suppression structure is designed on the non-radiating side of the waveguide, effectively confining electromagnetic energy through a symmetrically distributed array of metallized vias, minimizing transmission loss and laying the foundation for high-efficiency radiation. Finally, by symmetrically arranging periodic dipole arrays on the upper and lower dielectric layers, combined with waveguide dispersion analysis and spatial harmonic theory, a wide-angle continuous scanning from end-fire to edge-fire direction is achieved, with a single beam scanning range of 95° and dual beams merging to cover a 190° spatial angular domain. Therefore, the antenna structure proposed in this invention achieves stable impedance matching and dual-beam radiation within the operating frequency band of 14 GHz to 25 GHz (relative bandwidth of 56.4%), with a total efficiency exceeding 86%, a radiation efficiency exceeding 95%, and a peak gain of 11.7 dBi. This invention effectively solves the technical challenges of traditional leaky wave antennas in balancing wide-angle scanning, dual-beam implementation, manufacturing cost, and radiation efficiency, providing a high-performance, low-cost, and easily integrated antenna solution for next-generation wireless communication systems. Attached Figure Description

[0022] Figure 1 A design flowchart of a half-mode dielectric ridge parallel plate waveguide dual-beam wide-angle scanning leaky wave antenna structure based on PCB technology is provided for this invention. Figure 2 This is a schematic diagram of the evolution process of a half-mode dielectric ridge parallel plate waveguide. Figure 3 This is a cross-sectional view of an HMDRPW structure based on full PCB manufacturing process; Figure 4 The simulation results show the electric field distribution of the HMDRPW structure implemented using full PCB technology. Figure 5 A schematic diagram of the cross-section of a transmission line with a non-radiative open aperture edge leakage suppression structure. Figure 6 Comparison of simulation results of electric field distribution with and without a loaded leakage suppression structure at the edge of a non-radiative open aperture; Figure 7 A comparison of the electric field amplitude variation along the non-radiative open aperture with and without a loaded leakage suppression structure; Figure 8 This is a three-dimensional exploded view of the antenna structure proposed in this invention; Figure 9The simulation results show the dispersion characteristics of the dual-beam HMDRPW LWA unit proposed in this invention. Figure 10 These are the simulation results of the antenna S-parameters proposed in this invention; Figure 11 The above are simulation results of the radiation pattern of the antenna proposed in this invention in the E-plane. Figure 12 The simulation results show the total efficiency and radiation efficiency of the antenna proposed in this invention. Detailed Implementation

[0023] To make the objectives, advantages and features of the present invention more apparent, the present invention will be further described in detail below with reference to specific embodiments.

[0024] Implementing a traditional wide-angle scanning leaky-wave antenna in the millimeter-wave band typically requires addressing the following major technical challenges: (1) Complex structure and high cost: Many high-performance leaky wave antennas use metal waveguides or multilayer complex dielectric structures, and their processing technology (such as precision CNC machining or low temperature co-fired ceramic technology) is usually costly and time-consuming. In addition, traditional metal waveguide structures are large in size and have high profiles, making them difficult to integrate with microwave and millimeter wave planar circuit systems. These problems severely limit the widespread application of this type of antenna in low-cost, highly integrated commercial systems (such as 5G / 6G communication and vehicle radar).

[0025] (2) Limited scanning performance: Existing leaky wave antennas based on PCB technology often have a narrow beam scanning range, making it difficult to achieve large-angle scanning over a wide frequency band. In particular, such designs generally suffer from the technical bottleneck of beam pointing angle design, i.e., they cannot achieve continuous beam coverage from end-fire (θ = -90°) to side-fire (θ = 0°) within the operating frequency band. This problem also makes traditional beam scanning LWA unsuitable for scenarios with high requirements for panoramic perception, such as environmental modeling for autonomous driving.

[0026] (3) Difficulty in balancing efficiency and integration: While pursuing wide bandwidth and wide-angle scanning, how to achieve stable and high-efficiency radiation of the antenna is a major challenge. Some structures may have excellent performance at specific frequencies, but their efficiency fluctuates greatly across the entire operating frequency band; or the simplicity and compact size of the antenna structure are sacrificed in order to improve performance.

[0027] Combined with appendix Figures 1 to 12This invention provides a half-mode dielectric ridged parallel-plate waveguide (HMDRPW) dual-beam wide-angle scanning leaky-wave antenna (LWA) structure implemented using printed circuit board (PCB) technology. The core structure, working principle, and design method of this antenna will be described in detail below.

[0028] Reference Figure 1 As shown, this invention discloses a design process for HMDRPW dual-beam wide-angle scanning LWA based on full PCB technology: S1. Design and construct the core structure of a half-mode dielectric ridge parallel plate waveguide transmission line based on full PCB technology; S2. A leakage suppression structure is designed at the non-radiative open aperture edge of the half-mode dielectric ridge parallel plate waveguide to suppress energy leakage. S3. Based on the dispersion characteristics of the half-mode dielectric ridge parallel plate waveguide and the spatial harmonic theory, a periodic radiating element is designed on the radiating open aperture side of the waveguide.

[0029] The design method for designing and constructing the core structure of a half-mode dielectric ridge parallel plate waveguide transmission line based on full PCB technology in S1 is as follows: First, the electromagnetic propagation characteristics of traditional HMDRPW are theoretically analyzed.

[0030] HMDRPW is an innovative waveguide structure with miniaturization potential, evolved from the traditional DRPW. Its design concept originates from the symmetrical trimming of the DRPW. For example... Figure 2 The diagram illustrates the evolution of a half-mode dielectric ridge parallel plate waveguide. A traditional DRPW structure is cut along its electric field symmetry plane (approximately equivalent to a magnetic wall), retaining half of its physical structure, thus forming an HMDRPW. Therefore, the fundamental transmission mode in an HMDRPW is highly similar to the half-field distribution of the fundamental mode (quasi-TEM mode) of a DRPW, with the electric field effectively confined to the remaining dielectric ridge region and propagating along it. HMDRPW inherits the wide single-mode bandwidth and low-loss characteristics of DRPW. Its core advantages are: firstly, its compact structure, with a physical cross-sectional area approximately half that of a DRPW, facilitating system miniaturization and integration; secondly, its naturally open aperture, where the cut surface forms a natural open boundary, allowing energy to be effectively coupled out or easily integrated with radiating elements, creating ideal conditions for achieving high-performance leaky antennas; and thirdly, its ease of integration, as this open structure is easier to integrate and interconnect with planar circuits, active devices, etc.

[0031] The phase constant of a conventional DRPW operating in quasi-TEM mode with zero cutoff frequency is... β It can be given by the following expression: ; in, ε r The relative permittivity of the dielectric ridge in the DRPW is given. k 0 represents the wave number in a vacuum. β y This is the phase constant of the DRPW transverse direction. β y The value of can be obtained by solving the following transcendental equation: ; in, t d Let be the width of the dielectric ridge in the DRPW. Based on structural symmetry, the phase constant of the fundamental mode of the HMDRPW can theoretically be approximately derived using the above formula. However, since the inherent internal field boundary in the DRPW is transformed into an open boundary in the HMDRPW, and this boundary cannot be completely equivalent to an ideal magnetic wall, this is the key difference between the two. This fundamental structural change leads to the broadening of the transverse electric field distribution and the weakening of field confinement in the HMDRPW, making its propagation constant significantly lower than that of the full-mode DRPW. To accurately describe the propagation characteristics of the HMDRPW, its phase constant must be corrected. Therefore, a compensation coefficient related to the dielectric properties of the dielectric ridge is introduced. γ And establish the corrected phase constant. β HM The expression is as follows: ; in, t 0 The width of the dielectric ridge in the HMDRPW is defined. This correction clarifies the decisive influence of boundary conditions on waveguide propagation characteristics, providing a more accurate theoretical basis for the design of various waveguide components and antennas based on HMDRPW. Secondly, based on the above analysis of the structural and transmission characteristics of HMDRPW, a three-layer transmission line core structure entirely based on PCB technology is designed and constructed. This structure consists of three dielectric substrate layers: upper, middle, and lower. The middle layer forms the dielectric ridge, and the upper and lower layers are symmetrically distributed, together forming a half-mode waveguide with open boundary characteristics, providing a basic transmission environment for subsequent radiation design and frequency scanning.

[0032] Reference Figure 3The cross-sectional view of the HMDRPW structure based on full PCB technology shown in the figure illustrates that the core transmission line of this invention is a technological innovation based on traditional HMDRPW. This HMDRPW structure is entirely constructed using PCB technology, consisting of three dielectric substrates (upper, middle, and lower) bonded together. The middle dielectric substrate forms the dielectric ridge of the waveguide; the bottom of the upper dielectric substrate is coated with copper to form the upper metal boundary, and the top of the lower dielectric substrate is coated with copper to form the lower metal boundary. These two metal boundaries correspond to the upper and lower metal plates in a traditional HMDRPW structure, respectively. The upper and lower metal boundaries, together with the dielectric ridge, constitute the core transmission line of the HMDRPW used in this invention.

[0033] It is worth emphasizing that traditional DRPWs and their half-mode structures (HMDRPWs) typically require a hybrid manufacturing process that combines PCB fabrication of the dielectric spine with CNC machining of the metal plate. This invention, however, completely abandons this approach. The entire HMDRPW structure is manufactured as a single unit using standard multilayer PCB processes, significantly simplifying the production process and laying the foundation for low-cost, high-integration, and mass production of antennas.

[0034] Reference Figure 4 The simulation results of the electric field distribution of the HMDRPW structure based on the full PCB process proposed in this invention are shown. The basic operating mode of this HMDRPW structure, implemented using the full PCB process, remains highly similar to the half-field distribution of the fundamental mode of a traditional DRPW, with the electric field energy effectively confined within the dielectric ridge and its adjacent region. This result demonstrates that the HMDRPW implemented using the full PCB process can maintain essentially the same electromagnetic characteristics as a traditional hybrid process HMDRPW.

[0035] In S2, a leakage suppression structure is designed at the non-radiative open aperture edge of the half-mode dielectric ridge parallel plate waveguide. The design method for suppressing energy leakage is as follows: First, at the open aperture on the other side of the waveguide that does not participate in radiation (i.e., the open aperture side away from the dielectric ridge), the upper and lower dielectric substrates are simultaneously extended outward by a specific width, and a row of closely arranged metallized vias is set at the cutoff position corresponding to the copper foil boundary. The two rows of vias are structurally symmetrically distributed, together forming an electromagnetic shielding boundary that penetrates the dielectric substrate, so as to effectively suppress transverse field leakage.

[0036] Secondly, by systematically optimizing structural parameters such as the width of the extended region, the diameter of the metallized vias, the spacing between the vias, and the arrangement period, effective lateral confinement of electromagnetic field energy is achieved. This optimized design can significantly suppress energy leakage on the non-radiating side caused by the open structure, thereby reducing transmission loss, improving overall energy utilization, and laying a solid structural foundation for the antenna to achieve high-efficiency radiation over a wide frequency band.

[0037] like Figure 5 The figure shows a schematic diagram of the transmission line cross-section with a non-radiative open aperture edge leakage suppression structure. As can be seen, the metallized via array does not alter the original dual-conductor waveguide structure of the HMDRPW, thus maintaining its basic operating mode unaffected. Figure 6 and Figure 7 The simulation results together verified the effectiveness of the non-radiative open aperture edge leakage suppression structure. Figure 6 By comparing the electric field distribution with and without the suppression structure, it is intuitively shown that the leakage of electromagnetic energy at the non-radiative open aperture is significantly suppressed; Figure 7 Further quantitative characterization was performed using electric field amplitude distribution curves along the edge of the non-radiating open aperture. The results show that the electric field amplitude is significantly reduced after introducing the suppression structure. Both sets of data consistently indicate that the structure can effectively control energy leakage on the non-radiating side, thereby significantly reducing the transmission loss of the transmission line in the corresponding frequency band and providing effective support for improving the overall transmission efficiency of the antenna.

[0038] Based on the dispersion characteristics and spatial harmonic theory of the half-mode dielectric ridge parallel plate waveguide in S3, the design method for designing periodic radiating elements on the radiating open aperture side of the waveguide is as follows: Based on the defined HMDRPW transmission line, and combining its dispersion characteristics and spatial harmonic theory, periodic dipoles are rationally arranged on the upper and lower surfaces of the waveguide as radiating elements. By systematically adjusting the size, arrangement period, and distribution of the dipoles, the impedance matching and radiation performance of the antenna are optimized, thereby achieving high-efficiency wide-angle frequency scanning within the target broadband.

[0039] The physical mechanism by which this antenna achieves wide-angle scanning originates from the leakage radiation theory. Dipole units, acting as radiating elements, are symmetrically arranged on the upper and lower dielectric substrates outside the HMDRPW structure. At the open aperture on the side where the waveguide participates in radiation (i.e., the open aperture side near the dielectric ridge), the upper and lower dielectric substrates are simultaneously extended outwards by a specific width. Thanks to the open aperture formed by the HMDRPW's cut surface, energy can be effectively coupled to the dipoles. Simultaneously, this arrangement coordinates with the field distribution of the HMDRPW's fundamental mode, naturally and synchronously exciting two completely symmetrical beams. Since the HMDRPW's fundamental mode is a slow-wave mode, periodic loading of the dipoles is required to excite higher-order spatial harmonics, thereby achieving effective leakage radiation. The condition for the -1st spatial harmonic to radiate outwards is: ; in, λ 0 represents the wavelength in a vacuum. p d The periodicity of the dipole arrangement. Its beam pointing angle. θ It is determined by the following formula: ; Reference Figure 8 The diagram shows a three-dimensional exploded view of the antenna. This invention provides a dual-beam leaky wave antenna implemented using a full PCB process. The antenna is fed using a grounded coplanar waveguide (GCPW) and connected to a matching load (not shown) at the end to absorb residual energy, thus ensuring impedance matching performance. To suppress energy leakage from the non-radiating side, two rows of symmetrically distributed, closely arranged metallized via arrays are provided near the non-radiating aperture edges of the upper and lower dielectric substrates. These via arrays penetrate the dielectric substrate, forming an effective electromagnetic shielding boundary. Their function is not to participate in radiation, but to confine electromagnetic energy within the waveguide, thereby significantly reducing transmission loss. Based on the HMDRPW transmission line, to achieve dual-beam radiation, periodic metal dipole arrays penetrating the substrate are respectively provided in the upper and lower dielectric substrates. The antenna's specific structure includes: an upper dielectric substrate, a copper foil at the bottom of the upper dielectric substrate, a metallized via array in the upper dielectric substrate near the non-radiating aperture side, a dipole (radiating element) in the upper dielectric substrate near the radiating aperture side, a dielectric ridge, a lower dielectric substrate, a copper foil at the top of the lower dielectric substrate, a metallized via array in the lower dielectric substrate near the non-radiating aperture side, a dipole (radiating element) in the lower dielectric substrate near the radiating aperture side, and a GCPW structure for feeding and terminal load absorption.

[0040] The antenna structure proposed in this invention uses Rogers RT5880 as the dielectric material for the upper and lower dielectric substrates and the dielectric ridge, with a relative permittivity of [missing information]. ε r = 2.2, loss tangent tan δ = 0.0009, with a thickness of 1.575 mm. The three-layer structure is integrally formed by bonding the adhesive layers together. The thickness of all copper foil layers (including the upper and lower metal boundaries and the conductor strip and ground layer in the GCPW structure) is uniformly 0.018 mm. Each dipole radiating unit is constructed through metallized vias.

[0041] For example Figure 8 The working principle of the dual-beam leaky wave antenna shown is described in detail below: Energy is fed into the GCPW, exciting the fundamental mode in the HMDRPW; as the energy propagates along the dielectric ridge, it is coupled through periodically distributed dipole units, exciting the -1st space harmonic and radiating it into free space. Specifically, by rationally designing the periodic parameters of the dipoles, the wavenumber at the low-frequency end is made close to the free-space wavenumber, thus supporting beam projection from the end-firing direction (…). θ The scan begins at -90°; as the frequency increases, the wavenumber change causes the beam to gradually point towards the side beam direction ( = -90°). θ= 0°) offset, ultimately achieving a wide-angle scanning range of over 95° for a single beam. Due to the complete symmetry of the upper and lower structures, two symmetrical beams can be excited simultaneously, and the dual beams are combined to cover a spatial angular domain of nearly 190°.

[0042] Figure 9 The simulation results of the dispersion characteristics of the dual-beam HMDRPW LWA unit proposed in this invention are presented. The normalized phase constant (…) is shown in the figure. β / k 0) As can be seen from the frequency curve, the structure consistently satisfies the radiation condition of the -1st spatial harmonic within the operating frequency band from 14 GHz to 25 GHz, and the dispersion curve changes smoothly and continuously. This characteristic ensures that the beam pointing angle can continuously scan with frequency, providing the necessary phase change basis for realizing wide-angle frequency scanning from end-fire to side-fire direction.

[0043] Figure 10 The S-parameter simulation results of the dual-beam HMDRPW LWA proposed in this invention are presented. The simulation curves show that the return loss of this antenna in the frequency band above 13.61 GHz is... S 11 |Below -10 dB, exhibiting good impedance matching characteristics. Within the dual-beam operating bandwidth of 14 GHz to 25 GHz, | S 11 |and| S 21 The values ​​are all less than -10 dB, indicating that the leaky antenna can effectively couple most of the input energy into free space, achieving efficient leaky radiation. Figure 11 Simulation results of the radiation pattern of the antenna of this invention in E-plane polar coordinates are presented. Analysis shows that within the ultra-wideband of 14 GHz to 25 GHz (relative bandwidth of 56.4%), the antenna achieves continuous forward beam scanning from the end-fire direction (-90°) through the side-fire direction (0°), with a dual-beam combining coverage of 190°, exhibiting excellent wide-angle scanning characteristics. Notably, the antenna achieves a peak gain of 11.7 dBi at 22 GHz. Figure 12 Simulation results of the antenna's overall efficiency and radiation efficiency within the 14 GHz to 25 GHz frequency band are presented. It can be seen that throughout the entire dual-beam operating frequency band, the antenna's overall efficiency consistently exceeds 86%, and its radiation efficiency exceeds 95%. This excellent high-efficiency radiation characteristic, combined with wide-angle scanning capability, fully verifies the comprehensive performance advantage of the proposed HMDRPW LWA structure in achieving wide-angle coverage while maintaining radiation directivity.

[0044] Compared to existing technologies, this invention achieves an ultra-wide scanning angle and stable, symmetrical dual-beam radiation. This is primarily attributed to the design of the HMDRPW LWA with a loaded dipole. The HMDRPW, as the basic transmission line, maintains the wide single-mode bandwidth of a traditional DRPW while possessing miniaturization potential. This allows the beam scanning bandwidth of the LWA designed based on this waveguide structure to be limited only by harmonic radiation conditions, enabling an ultra-wide operating bandwidth. Furthermore, due to the complete symmetry of the upper and lower structures and the placement of the dipole outside the open aperture of the waveguide, this LWA can achieve symmetrical upper and lower beams, overcoming the difficulty of end-firing in traditional LWAs. Within a frequency band of up to 56.4%, this invention can continuously scan from end-firing to near-side-firing, with a single beam coverage of up to 95° and dual-beam combined coverage of nearly 190°.

[0045] Secondly, this invention achieves high performance previously only achievable through hybrid manufacturing processes using purely low-cost PCB technology. The entire antenna eliminates CNC metal machining, significantly reducing manufacturing costs and time, and improving integration with planar circuitry. Crucially, the edge-metallized via array (edge ​​leakage control structure) introduced in this invention significantly reduces transmission loss by suppressing electromagnetic energy leakage on the non-radiating side. This design ensures low-loss transmission characteristics of the waveguide throughout the entire bandwidth, a vital foundation for achieving high radiation efficiency and ensuring high performance and stability in practical systems.

[0046] In summary, this invention successfully achieves an excellent balance between antenna radiation performance and manufacturing cost, providing a full PCB leaky antenna solution that combines wide bandwidth, wide-angle scanning, stable dual beams, high efficiency, and low cost, perfectly meeting the growing demand for high-performance antennas in modern wireless systems.

[0047] It should be noted that any process or method description in the embodiments can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as should be understood by those skilled in the art to which the embodiments of the invention pertain.

[0048] It should be noted that the logic and / or steps in the embodiments, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0049] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0050] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0051] Furthermore, in the embodiments of the present invention, the functional modules can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0052] The storage media mentioned above can be read-only memory, disk, or optical disk, etc.

[0053] The above embodiments have provided a detailed description of the technical solution of the present invention. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, those skilled in the art can make various modifications, but any modifications that are equivalent to or similar to the present invention fall within the scope of protection of the present invention.

[0054] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A design method for a dual-beam wide-angle scanning leaky wave antenna based on a half-mode dielectric ridge parallel plate waveguide using PCB technology, characterized in that, Includes the following steps: Step S1: Design and construct the core structure of a half-mode dielectric ridge parallel plate waveguide transmission line based on full PCB technology; Step S2: Design a leakage suppression structure at the non-radiative open aperture edge of the half-mode dielectric ridge parallel plate waveguide to suppress energy leakage; Step S3: Based on the dispersion characteristics of the half-mode dielectric ridge parallel plate waveguide and the spatial harmonic theory, design periodic radiating elements on the radiating open aperture side of the waveguide.

2. The method according to claim 1, characterized in that, Step S1 specifically includes the following steps: Theoretical analysis of the electromagnetic propagation characteristics of HMDRPW: The phase constant β of a conventional DRPW operating in quasi-TEM mode with zero cutoff frequency is given by the following expression: ； Where εr is the relative permittivity of the dielectric ridge in the DRPW, k0 is the wave number in vacuum, and βy is the transverse phase constant of the DRPW. The value of βy is obtained by solving the following transcendental equation: ； Where td is the width of the medium ridge in DRPW; A compensation coefficient γ related to the dielectric properties of the dielectric ridge is introduced, and the expression for the corrected phase constant βHM is established as follows: ； Where t0 is the width of the medium ridge in HMDRPW; The upper, middle and lower dielectric substrates are laminated together to form a single unit; In this structure, the middle dielectric substrate forms the dielectric ridge of the waveguide; the bottom of the upper dielectric substrate is coated with copper to form the upper metal boundary, and the top of the lower dielectric substrate is coated with copper to form the lower metal boundary. These two metal boundaries correspond to the upper and lower metal plates in the traditional HMDRPW structure, respectively. The upper and lower metal boundaries and the dielectric ridge together form the core transmission line of the HMDRPW, thereby forming the half-mode dielectric ridge parallel plate waveguide.

3. The method according to claim 1, characterized in that, Step S2 specifically includes the following steps: At the open aperture on the other side of the waveguide where it does not participate in radiation, the upper and lower dielectric substrates are simultaneously extended outward by a specific width to form an extension region; Two rows of closely spaced and symmetrically distributed metallized via arrays are provided at the copper foil boundary of the extended region. The metallized via arrays penetrate the dielectric substrate to form an electromagnetic shielding boundary and suppress the lateral leakage of electromagnetic energy from the non-radiative side.

4. The method according to claim 1, characterized in that, Step S3 specifically includes the following steps: A periodic dipole array is symmetrically arranged on the upper and lower dielectric substrates on the radiating open aperture side of the half-mode dielectric ridge parallel plate waveguide. The condition under which the -1st spatial harmonic can radiate outward is: ； in, λ 0 represents the wavelength in a vacuum. p d The arrangement period of the dipoles, its beam pointing angle θ It is determined by the following formula: 。 5. A half-mode dielectric ridge parallel plate waveguide dual-beam wide-angle scanning leaky wave antenna structure based on PCB technology, characterized in that, include: Core structure of half-mode dielectric ridge parallel plate waveguide transmission line based on full PCB process; The leakage suppression structure at the non-radiative open aperture edge of the half-mode dielectric ridge parallel plate waveguide is used to suppress energy leakage; Based on the dispersion characteristics of the half-mode dielectric ridge parallel plate waveguide and the spatial harmonic theory, a periodic radiating element is formed on the radiating open aperture side of the waveguide.

6. The structure as described in claim 5, characterized in that, The core structure of the half-mode dielectric ridge parallel plate waveguide transmission line includes: The upper dielectric substrate has a copper-clad bottom layer forming an upper metal boundary; The middle dielectric substrate forms the dielectric ridge of the waveguide; The lower dielectric substrate has a copper-clad top layer forming a lower metal boundary. The upper metal boundary and the lower metal boundary correspond to the upper and lower metal plates in the traditional HMDRPW structure, respectively; the upper metal boundary and the lower metal boundary together with the dielectric ridge constitute the core transmission line of HMDRPW, thereby forming the half-mode dielectric ridge parallel plate waveguide. The upper, middle and lower dielectric substrates are integrally formed by PCB lamination process.

7. The structure as described in claim 6, characterized in that, The leakage suppression structure includes: At the open aperture on the other side of the waveguide where it does not participate in radiation, the upper dielectric substrate and the lower dielectric substrate extend outward synchronously to form an extension region of a specific width. Two rows of closely spaced and symmetrically distributed metallized via arrays are located at the copper foil boundary of the extended region. The metallized via arrays penetrate the dielectric substrate to form an electromagnetic shielding boundary, suppressing the lateral leakage of electromagnetic energy from the non-radiative side.

8. The structure as described in claim 6, characterized in that, The periodic radiation unit includes: A periodic dipole array symmetrically arranged on the upper and lower dielectric substrates on the radiating open aperture side of the half-mode dielectric ridge parallel plate waveguide. The condition under which the -1st spatial harmonic can radiate outward is: ； in, λ 0 represents the wavelength in a vacuum. p d The arrangement period of the dipoles, its beam pointing angle θ It is determined by the following formula: 。

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