Parallel staggered comb-shaped array antenna for vehicle-mounted millimeter wave radar

Abstract

The invention discloses a parallel staggered comb-shaped array antenna for a millimeter wave vehicle-mounted radar. The parallel staggered comb-shaped array antenna comprises a parallel staggered comb-shaped antenna plate, a dielectric plate and a grounding plate which are sequentially stacked from top to bottom. The parallel staggered comb-shaped antenna plate comprises a power distribution unit, an impedance matching unit and two comb-shaped feed units, wherein the power distribution unit is connected with the two comb-shaped feed units through the impedance matching unit. The comb-shaped feed units adopt serial network design, each comb-shaped feed unit comprises nine radiation array elements with specific sizes, signal amplitudes are distributed in a Dohr-Chebyshev mode, topology is centrosymmetric with a main array element as a center, and the array elements are arranged in a staggered mode along a feeder line to form a periodic comb-shaped radiation structure. According to the invention, the efficiency is improved through staggered arrangement of the array elements, the symmetry of a directional diagram is ensured through centrosymmetric arrangement, the bandwidth is expanded through independent matching of resonant frequency gradient distribution, the gain is increased through the parallel comb-shaped feed unit, key performances of high feed efficiency, symmetric directional diagram, large bandwidth, high gain and the like required by the vehicle-mounted radar are realized, and the antenna has important engineering application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of millimeter wave antennas, and in particular relates to a parallel interleaved comb array antenna for a vehicle-mounted millimeter wave radar. Background Art

[0002] With the rapid development of intelligent driving technology, automotive millimeter-wave radar, as a core sensor in intelligent driving systems, has a direct impact on the vehicle's environmental perception capabilities. Current automotive radar antenna technology faces three major challenges: first, achieving high-performance radiation within a limited installation space; second, the difficulty in balancing feed efficiency and bandwidth; and finally, the difficulty in balancing pattern symmetry and beam stability.

[0003] As autonomous driving levels increase, higher requirements are placed on millimeter-wave radar antennas. Modern intelligent driving systems require antennas to not only provide basic detection capabilities but also enable multi-target tracking, high-precision ranging, and stable operation in complex environments. These demands are directly driving innovations in antenna array technology in areas such as topology, feed methods, and material processing.

[0004] The parallel-fed array can achieve a wide impedance bandwidth through a distributed resonant structure, but its gain performance is limited by phase accumulation error and transmission line loss. While the parallel-fed array can achieve high gain through equal-amplitude and in-phase excitation, it is limited by the frequency response of the feeding network and its operating bandwidth is usually narrow.

[0005] To address these technical bottlenecks, this paper proposes an innovative parallel interleaved comb array antenna design. Through a unique array topology and optimized feed network design, this solution aims to simultaneously address key technical challenges such as high feed efficiency, wide operating bandwidth, and excellent pattern symmetry, providing a more reliable millimeter-wave radar antenna solution for next-generation intelligent driving systems. Summary of the Invention

[0006] The purpose of this invention is to address the key technical defects of existing vehicle-mounted millimeter-wave radar antennas, such as low feeding efficiency, poor radiation pattern symmetry, narrow operating bandwidth and insufficient gain. A parallel staggered comb array antenna for vehicle-mounted millimeter-wave radar is proposed. Through innovative array topology and feed network optimization, a synergistic improvement in feeding efficiency, radiation pattern symmetry, operating bandwidth and array gain is achieved in the millimeter-wave frequency band.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A parallel staggered comb array antenna for an on-board millimeter-wave radar comprises a parallel staggered comb antenna plate, a dielectric plate, and a ground plate stacked in sequence from top to bottom. The parallel staggered comb antenna plate comprises a power distribution unit, an impedance matching unit, and at least two comb feed units. The comb units are connected at the system level via the power distribution unit and the impedance matching unit. The comb feed unit comprises one to five levels of array elements and a feed line. The first level array element is the main array element and is located in the middle. The remaining array elements are staggered in sequence along the x-axis at both ends of the feed line along both sides of the feed line, and form a comb topology arrangement structure symmetrically along the y-axis to achieve equal-amplitude and in-phase excitation of the radiation field and obtain a highly directional radiation beam.

[0009] Furthermore, the two or more comb feeding units and the power distribution network corresponding to the number are used, and a corresponding impedance matching unit is designed for each comb feeding unit, and then the multiple comb feeding units are connected to the corresponding power distribution network in sequence through the impedance matching unit.

[0010] Furthermore, the distance between adjacent comb-shaped feeding units is 0.5λ, where λ is the free space wavelength corresponding to the center frequency.

[0011] Furthermore, the comb-shaped feeding unit includes nine feeding array elements, the feed line connects the array elements in series, and the array elements are staggered on both sides of the feed line to form a comb-shaped radiation structure with periodic characteristics.

[0012] Furthermore, the nine feeding array elements include a primary array element located in the middle of the feed line, and the remaining array elements are all dual-element designs, which are symmetrically distributed on both sides of the primary array element in the order of secondary, tertiary, fourth, and fifth levels.

[0013] Furthermore, the widths of the nine feeding array elements are all 0.35λ±0.05λ, where λ is the free space wavelength corresponding to the center frequency.

[0014] Furthermore, the center frequency of the band corresponding to the primary array element, and its length L and width W are:

[0015]

[0016] Among them, ε r refers to the speed of light, f refers to the center frequency, ε r Refers to the dielectric constant of the dielectric plate, λ g is the waveguide wavelength in the medium, ΔL is the equivalent radiation gap length, ε e is the effective dielectric constant.

[0017] Furthermore, the length ratio of the second to fifth level array elements is designed according to the Dolph-Chebyshev distribution:

[0018]

[0019] Among them, L n is the length of the nth array element, T N-1 is the N-1 order Chebyshev polynomial, x0 is the parameter determined by the sidelobe suppression ratio, and N=9.

[0020] Furthermore, the nine array elements are arranged at non-equidistant intervals, and the intervals between adjacent array elements gradually change in the range of 0.13λ to 0.25λ, where λ is the free space wavelength corresponding to the center frequency.

[0021] Furthermore, the dielectric plate is made of Rogers 3003 material, has a dielectric constant of 3.07, and a thickness of 0.13 mm; the parallel staggered comb antenna plate and the ground plate are made of copper, and have a thickness of 0.035 mm.

[0022] The beneficial effects of the present invention are:

[0023] 1. The comb array antenna designed in this invention consists of nine radiating elements, which are arranged in a staggered and symmetrical pattern along both sides of the feed line. It adopts a mirror topology structure based on the central element and forms periodic comb-shaped radiating units according to a preset geometric distribution pattern. This layout significantly improves space utilization efficiency and feed network performance.

[0024] 2. The present invention adopts a centrosymmetric comb array arrangement, ensuring the symmetry of the E-plane and H-plane radiation patterns through strict geometric symmetry, thereby improving beam consistency and reducing sidelobe levels, ultimately enhancing the signal-to-noise ratio performance of the radar system.

[0025] 3. The present invention adopts a multi-level symmetrical interleaved series-fed structure. By optimizing the non-uniform distribution of array element spacing, an equivalent spatial harmonic coupling effect is formed in the array, thereby expanding the antenna operating bandwidth. This bandwidth increase effectively improves the angular resolution performance of the radar system.

[0026] 4. Through the coordinated design of the impedance matching unit and the power distribution unit, multiple comb feed units are optimized and cascaded. In the present invention, two comb feed units are connected in parallel for the best effect, which more effectively improves the radiation gain characteristics of the antenna array.

[0027] 5. The present invention is based on a microstrip antenna structure and adopts a multi-stage parallel comb array form. Through the coordinated design of the radiation unit, feeding network and impedance matching structure, the electrical performance and system integration capability of the antenna are significantly optimized. This type of antenna achieves an effective bandwidth of up to 3.017 GHz in the 77-80 GHz frequency band, meeting the radar system's requirements for a wide-band operating range; its maximum gain at the center frequency reaches 15.06 dB, and the return loss can reach as low as -31.73 dB, reflecting excellent radiation efficiency and echo suppression capabilities. In addition, the overall structure of the antenna is compact and the layout is reasonable, which is suitable for the miniaturization integration requirements of millimeter-wave radar systems. The design can be mass-produced through standard printed circuit board (PCB) technology, and has engineering advantages such as high processing precision, low loss, and controllable costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the parallel interleaved comb array antenna provided by the present invention.

[0029] Figure 2 It is a structural annotation schematic diagram of the parallel interleaved comb array antenna provided by the present invention.

[0030] Figure 3 This is a graph showing the relationship between return loss and frequency of the parallel interleaved comb array antenna provided by the present invention.

[0031] Figure 4 The present invention provides a parallel interleaved comb array antenna gain pattern.

[0032] Figure 5 The antenna radiation pattern of the parallel interleaved comb array antenna provided by the present invention.

[0033] Figure 6 This is the 3D antenna gain pattern of the parallel interleaved comb array antenna provided by the present invention.

[0034] Figure 7 This is the minimum echo loss value of the parallel interleaved comb array antenna provided by the present invention.

[0035] Figure 8 The parallel interleaved comb array antenna provided by the present invention has a gain bandwidth of -3dB. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings.

[0037] The present invention provides a parallel interleaved comb array antenna for vehicle-mounted millimeter wave radar, according to Figure 2 As shown, its structure mainly includes: a parallel staggered comb antenna plate 1 on the upper layer, a dielectric plate 2 in the middle, and a ground plate 3 on the bottom layer;

[0038] The parallel staggered comb antenna board 1 includes a power distribution unit 6, an impedance matching unit 5, and two comb feeding units 4; the comb feeding unit 4 is connected to the power distribution unit 6 through the impedance matching unit 5;

[0039] The comb feed unit 4 is mainly composed of a primary array element 7, a secondary array element 8, a tertiary array element 9, a quaternary array element 10, a quinary array element 11, a feed line 12, and some components. The primary array element 7 is the main array element and is arranged on one side of the center of the feed line 12. The remaining array elements are staggered along the x-axis at both ends of the feed line 12, and the entire comb feed unit 4 is formed in a symmetrical topology along the y-axis.

[0040] Furthermore, the array antenna utilizes a three-layer stacked structure, consisting of the following from top to bottom: Parallel interlaced comb antenna plate 1: Made of copper (thickness 0.035mm); Dielectric plate 2: Made of Rogers 3003 material (thickness 0.13mm), with a dielectric constant of 3.07, used to support the microstrip antenna and optimize electromagnetic wave transmission; Ground plate 3: Made of copper (thickness 0.035mm), providing a complete ground reflector to reduce back radiation.

[0041] Furthermore, the impedance matching unit 5 is a structure for matching the input impedance of the comb feed unit 4 with the output impedance of the power distribution network, so as to minimize signal reflection loss and ensure impedance compatibility with the standard radio frequency system.

[0042] Furthermore, the power distribution unit 6 adopts a T-type power distribution network to realize a one-to-two feeding structure for dividing the transmission power, so as to simultaneously excite two groups of antenna elements and ensure the symmetry of the radiation field pattern.

[0043] Furthermore, the two comb-shaped feeding units 4 are spaced 0.5 wavelengths apart to achieve in-phase superposition radiation of the array antenna and effectively suppress the grating lobe effect.

[0044] Furthermore, the comb feed unit 4 adopts a symmetrical multi-level array element layout, consisting of 9 array elements, which are arranged in a comb-like topology along both sides of the feed line 12. The symmetrically distributed multi-level array element structure realizes equal amplitude and in-phase excitation of the radiation field, thereby obtaining a highly directional radiation beam.

[0045] Furthermore, a hierarchical array element structure is employed: a primary array element (7:1) serves as the radiating core and is located at the center of the feeder. Secondary symmetrical array elements utilize four pairs of hierarchical elements, including a pair of secondary array elements (8), a pair of tertiary array elements (9), a pair of quaternary array elements (10), and a pair of quinary array elements (11). These secondary array elements are arranged alternately along the feeder, forming a strictly y-axis symmetrical structure to suppress pattern sidelobes.

[0046] Furthermore, the length and width of the primary array element 7 can be approximately calculated by the following formula:

[0047]

[0048] Among them, ε r refers to the speed of light, f refers to the center frequency, ε r Refers to the dielectric constant of the dielectric plate, λ g is the waveguide wavelength in the medium, ΔL is the equivalent radiation gap length, ε e The size of the primary array element 7 is determined by the center frequency solution formula, which is used to ensure that the array element achieves resonance characteristics in the target frequency band and optimizes radiation efficiency.

[0049] Furthermore, the widths of the nine array elements are all 0.35λ±0.05λ, where λ is the free space wavelength corresponding to the center frequency. By maintaining the consistency of the array element width, it is ensured that each array element has similar resonance characteristics.

[0050] Furthermore, the length and width of the main array element among the nine array elements have been calculated, and the length ratios of the remaining array elements are designed according to the Dolph-Chebyshev distribution, satisfying:

[0051]

[0052] Among them, L n is the length of the nth array element, T N-1 is the N-1 order Chebyshev polynomial, x0 is the parameter determined by the sidelobe suppression ratio, N=9, and by optimizing the array excitation amplitude distribution, controllable sidelobe level suppression is achieved while ensuring high gain.

[0053] Furthermore, the nine array elements are arranged at non-uniform intervals, and the spacing between adjacent elements gradually varies in the range of 0.13λ to 0.25λ, where λ is the free space wavelength corresponding to the center frequency. By constructing a non-uniform array structure, the antenna aperture efficiency is optimized, and multiple resonant modes are coupled to expand the operating bandwidth.

[0054] Example:

[0055] This example is based on a Rogers 3003 dielectric substrate with a dielectric constant of 3.07 and a thickness of 0.127 mm. The antenna structure's top and ground layers are constructed of 1-oz copper metal for the radiating and feeding layers, respectively. The antenna measures 60 mm × 30 mm × 0.134 mm, making it compact and suitable for integration into millimeter-wave radar systems.

[0056] like Figure 1 and Figure 2As shown, the antenna used in this embodiment features a nine-element comb array structure, staggered along the feeder lines for an overall centrally symmetrical layout. This mirror-symmetric topology, constructed with the central radiating element as a reference, strictly adheres to a pre-defined geometric distribution pattern to form a periodic comb-shaped radiating element. This structure significantly improves array space utilization and effectively simplifies the feed network, achieving a compact, high-performance integrated design.

[0057] like Figure 4 , Figure 5 , Figure 8 As shown in the figure, through the symmetrical array element arrangement, this antenna achieves good pattern symmetry on the E-plane and H-plane, effectively reducing the sidelobe level and improving the consistency of the main beam. Measured results show that at a frequency of 77 GHz, the main lobe direction of the beam is stable, with an E-plane beam coverage angle of -8.25° to 10.53° and an H-plane beam coverage angle of -23.90° to 23.72°, verifying the structure's excellent beam control capability in radar imaging.

[0058] like Figure 3 As shown, the antenna utilizes a multi-stage symmetrically interleaved array feed scheme. Based on an optimized design with non-uniform spacing, this design induces spatial harmonic coupling within the array, significantly expanding the operating bandwidth. The antenna's measured bandwidth covers 76.964 GHz to 79.981 GHz, reaching a bandwidth of 3.017 GHz, meeting the broadband requirements of narrowband millimeter-wave radar for high-resolution imaging.

[0059] like Figure 6 and Figure 7 As shown, the antenna's power distribution unit and impedance matching network are collaboratively optimized to ensure uniform power transmission and voltage standing wave ratio control between the comb feed units. At the 79 GHz center frequency, the antenna achieves a maximum gain of 15.06 dB and a minimum return loss of -31.73 dB, demonstrating excellent overall gain-bandwidth performance.

[0060] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A parallel interleaved comb array antenna for vehicle-mounted millimeter-wave radar, characterized by: The invention comprises a parallel staggered comb antenna plate (1), a dielectric plate (2) and a ground plate (3) stacked in sequence from top to bottom; the parallel staggered comb antenna plate (1) comprises a power distribution unit (6), an impedance matching unit (5) and at least two comb feeding units (4); the comb feeding units (4) are connected at the system level through the power distribution unit (6) and the impedance matching unit (5); the comb feeding unit (4) comprises one to five levels of array elements (7 to 11) and a feed line (12); the first level array element (7) is a main array element and is located in the middle position, and the remaining array elements are staggered in sequence along both sides of the feed line (12) on the x-axis at both ends of the feed line, and form a comb topology arrangement structure symmetrically along the y-axis, so as to realize equal amplitude and in-phase excitation of the radiation field and obtain a highly directional radiation beam.

2. The parallel interleaved comb array antenna for a vehicle-mounted millimeter-wave radar according to claim 1, characterized in that: At least two comb feeding units (4) are used, and a power distribution network (6) corresponding to the number thereof is used, and a corresponding impedance matching unit (5) is designed for each comb feeding unit (4), and then all the comb feeding units (4) are sequentially connected to the corresponding power distribution network (6) through the impedance matching units (5).

3. The parallel interleaved comb array antenna for a vehicle-mounted millimeter-wave radar according to claim 1 or 2, characterized in that: Adjacent comb-shaped feeding units (4) are spaced 0.5λ apart, where λ is the free space wavelength corresponding to the center frequency.

4. The parallel interleaved comb array antenna for a vehicle-mounted millimeter-wave radar according to claim 1, characterized in that: The comb-shaped feeding unit (4) comprises nine feeding array elements, the feed line (12) connects the array elements in series, and the array elements are staggered and distributed on both sides of the feed line to form a comb-shaped radiation structure with periodic characteristics.

5. The parallel interleaved comb array antenna for vehicle-mounted millimeter-wave radar according to claim 4, characterized in that: The nine feeding array elements include a primary array element (7) located in the middle of the feed line (12), and the remaining array elements are all dual-element designs and are symmetrically distributed on both sides of the primary array element (7) in the order of secondary, tertiary, quaternary, and fifth levels.

6. The parallel interleaved comb array antenna for a vehicle-mounted millimeter-wave radar according to claim 1 or 4, characterized in that: The widths of the nine feeding array elements are all 0.35λ±0.05λ, where λ is the free space wavelength corresponding to the center frequency.

7. The parallel interleaved comb array antenna for a vehicle-mounted millimeter-wave radar according to claim 1 or 5, characterized in that: The first-level array element (7) corresponds to the center frequency of the band, and its length L and width W are: Among them, ε r refers to the speed of light, f refers to the center frequency, ε r Refers to the dielectric constant of the dielectric plate, λ g is the waveguide wavelength in the medium, ΔL is the equivalent radiation gap length, ε e is the effective dielectric constant.

8. The parallel interleaved comb array antenna for vehicle-mounted millimeter-wave radar according to claim 7, characterized in that: The length ratio of the second to fifth level array elements (8 to 11) is designed according to the Dolph-Chebyshev distribution: Among them, L n is the length of the nth array element, T N-1 is the N-1 order Chebyshev polynomial, x0 is the parameter determined by the sidelobe suppression ratio, and N=9.

9. The parallel interleaved comb array antenna for vehicle-mounted millimeter-wave radar according to claim 5, characterized in that: The nine array elements are arranged at non-equidistant intervals, and the intervals between adjacent array elements gradually change in the range of 0.13λ to 0.25λ, where λ is the free space wavelength corresponding to the center frequency.

10. The parallel interleaved comb array antenna for vehicle-mounted millimeter-wave radar according to claim 1, characterized in that: The dielectric plate (2) is made of Rogers 3003 material, has a dielectric constant of 3.07, and a thickness of 0.13 mm; the parallel interlaced comb antenna plate (1) and the ground plate (3) are made of copper, and have a thickness of 0.035 mm.

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