A micro-coaxial ultra-wideband Vivaldi antenna and a half-mode Vivaldi antenna

Abstract

The application discloses a micro-coaxial ultra-wideband Vivaldi antenna and a half-mode Vivaldi antenna, the micro-coaxial ultra-wideband Vivaldi antenna comprising a coaxial feeding structure, a fan-shaped feed source and a metal cavity; the coaxial feeding structure comprising a coaxial inner core and a coaxial outer conductor, the coaxial inner core being suspendedly arranged inside the coaxial outer conductor, one end of the coaxial inner core being connected with the fan-shaped feed source through a coaxial matching section, and the other end being a free end; the fan-shaped feed source being suspendedly arranged in the metal cavity, a matching circular hole being formed on the metal cavity on one side of the fan-shaped feed source, the metal cavity being provided with an index gradient type curve opening, and the matching circular hole and the index gradient type curve opening being connected through an inclined straight line gap; comb-shaped gaps being formed on both sides of the metal cavity; and the metal cavity being connected with the coaxial outer conductor; the coaxial structure is used to reduce antenna loss, so that the antenna can work at high frequency; the index gradient type curve opening, the comb-shaped gaps and the matching circular hole are used to enable the Vivaldi antenna to realize wider impedance matching, increase the bandwidth of the Vivaldi antenna and maintain good gain.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a micro-coaxial ultra-wideband Vivaldi antenna and a half-mode Vivaldi antenna. Background Technology

[0002] Ultra-wideband (UWB) antennas, as a key technology in modern wireless systems, leverage their nanosecond-level time-domain pulse signal processing capabilities and GHz-level operating bandwidth to achieve high-precision positioning while exhibiting excellent multipath interference suppression characteristics. The low power spectral density of these antennas allows them to coexist with other communication standards (such as Wi-Fi and Bluetooth) in dense electromagnetic environments. This technological advantage has made them highly sought after in fields such as radar detection, short-range communication (such as 5G / 6G), and medical imaging.

[0003] Among numerous UWB antenna configurations, the Vivaldi antenna achieves a smooth transition of electromagnetic waves from a quasi-static field to free-space waves through its unique exponentially tapered slot line structure. This tapered discontinuity design not only ensures ultra-wideband impedance matching but also endows the antenna with high gain due to its tapered horn-shaped radiating aperture. Research shows that the operating bandwidth can be further extended by introducing elliptical arc slot line correction or composite dielectric loading techniques. This reconfigurable structure gives it unique advantages in phased array radar beamforming and millimeter-wave MIMO systems. Notably, recent breakthroughs in flexible substrate materials and 3D printing manufacturing processes have further propelled the innovative applications of this type of antenna in wearable medical sensors and conformal radar systems.

[0004] Patent CN105206937A discloses a Vivaldi ultra-wideband antenna based on micro-coaxial technology, including a microwave substrate. A metal radiating surface is disposed on the front end of the top of the microwave substrate. The microwave substrate and the metal radiating surface constitute an antenna radiating element. A radiating opening with a specific curvature is formed in the front end of the metal radiating surface. A section of the rear microwave substrate behind the metal radiating surface is etched with... shaped groove, A strip-shaped inner conductor with a matching shape is placed in the groove. The lower front end extends horizontally forward beyond the upper front end, inner conductor The upper and lower front ends are respectively connected to inclined transition structures, inner conductor The upper side is connected to the bottom rear end of the metal radiating surface via a connecting transition structure, inner conductor The inner wall of the substrate is supported by photoresist pillars, and an outer conductor is also included, which is fitted over the inner conductor. Photoresist pillars also support the inner wall of the outer conductor. An antenna slot is formed at the rear end of the outer conductor. The microcoaxial feed unit is composed of the inner conductor, outer conductor, photoresist pillars, and transition structure. A microwave circuit unit is also provided on the bottom surface of the microwave substrate. The microwave circuit unit consists of a microwave chip and a microstrip line. The input and output terminals of the microwave chip are connected to the transition structure at the lower front end of the inner conductor through the microstrip line. The ground of the microwave chip is connected to the outer conductor. The microwave substrate is used as the medium for the ultra-wideband Vivaldi antenna, and as the carrier for the microcoaxial cable and microwave chip. The ultra-wideband Vivaldi antenna is a planar printed antenna. Antenna radiation patterns are designed and processed on one side of the microwave substrate, and gold plating is performed to form 2-24GHz ultra-wideband radiation characteristics. The microwave signal is introduced through a slot line and directly fed by the inner conductor of the microcoaxial cable to realize the Vivaldi ultra-wideband feed structure. Although the Vivaldi antenna disclosed in this patent uses a micro-coaxial structure to achieve its basic functions, giving the antenna ultra-wideband characteristics, its maximum operating frequency is only 24GHz, which has not yet reached the millimeter wave band, thus limiting the antenna's application scenarios.

[0005] Patent CN117728155A discloses a 2-70GHz ultra-wideband, all-metal Vivaldi antenna, comprising a metal plate, a supporting base plate at the bottom of the metal plate, a coaxial connector passing through the supporting base plate and connecting to the metal plate, an exponentially tapered curve opening on the upper inner side of the metal plate, a matching circle on the lower part of the metal plate, and an inclined slot on the metal plate between the exponentially tapered curve opening and the matching circle. The starting end of the exponentially tapered curve opening is connected to one end of the inclined slot, and the other end of the inclined slot is connected to the matching circle. The inner conductor of the coaxial connector is in contact with the upper surface of the end where the inclined slot and the matching circle are connected. Traditionally designed Vivaldi antennas rarely operate at frequencies of 40GHz and above. This Vivaldi antenna, by optimizing the thickness of the Vivaldi metal plate, allows the antenna sample to operate at frequencies greater than 70GHz, with a return loss exceeding 10dB. The Vivaldi antenna disclosed in this patent has a sufficiently wide operating bandwidth and operates at millimeter-wave frequencies. However, it is made entirely of metal, which means that although its loss is less than that of the Vivaldi antenna manufactured using PCB technology, it is still greater than that of the Vivaldi antenna manufactured using micro-coaxial technology. Moreover, the overall size and volume of the antenna are relatively large, and the addition of a large metal base plate at the bottom of the antenna is not conducive to the miniaturization of the antenna.

[0006] In millimeter-wave and terahertz frequency band applications, antennas based on microcoaxial structures exhibit unique engineering value due to their wide bandwidth and low loss. Microcoaxial structures utilize air cavities or low-dielectric-constant composite materials as the supporting medium between the inner coaxial conductor and the outer conductor, significantly reducing ohmic loss and dielectric dispersion effects at high frequencies, resulting in a substantial improvement in radiation efficiency compared to traditional microstrip structures. Benefiting from quasi-TEM wave propagation characteristics and characteristic impedance stability, these antennas maintain an ultra-wide impedance bandwidth while possessing excellent high-order mode suppression capabilities, making them particularly suitable for multi-band converged communication systems. From a manufacturing perspective, microcoaxial antennas can be three-dimensionally stacked and integrated using photolithography, simplifying antenna design and reducing costs through modular manufacturing.

[0007] Therefore, there is an urgent need to propose a Vivaldi antenna for the 10-100 GHz band that is simple in structure, miniaturized, ultra-wideband, low-loss, and high-radiation-efficiency. Summary of the Invention

[0008] The purpose of this invention is to provide a micro-coaxial ultra-wideband Vivaldi antenna and a half-mode Vivaldi antenna to solve one or more of the aforementioned technical problems. The micro-coaxial ultra-wideband Vivaldi antenna and the half-mode Vivaldi antenna provided by this invention have the characteristics of miniaturization, large bandwidth, high gain and simple structure, and can be widely used in a variety of microwave systems, especially in radar, satellite and other fields.

[0009] To achieve the above objectives, this invention provides a micro-coaxial ultra-wideband Vivaldi antenna, comprising a coaxial feed structure, a fan-shaped feed, and a metal cavity. The coaxial feed structure includes a coaxial inner core and a coaxial outer conductor. The coaxial inner core is suspended inside the coaxial outer conductor. One end of the coaxial inner core is connected to the fan-shaped feed through a coaxial matching section, and the other end is a free end. The fan-shaped feed is suspended in the metal cavity. A matching circular hole is formed on one side of the metal cavity, and an exponentially tapered curved opening is formed in the metal cavity. The matching circular hole and the exponentially tapered curved opening are connected by an inclined straight slit. Comb-shaped slits are formed on both sides of the metal cavity. The metal cavity is connected to the coaxial outer conductor.

[0010] Furthermore, multiple SU-8 support structures are spaced apart along the axial direction in the coaxial power supply structure. The SU-8 support structure connects the coaxial inner core and the coaxial outer conductor. The SU-8 support structure uses a negative photoresist based on epoxy resin. Release holes are set around the coaxial outer conductor of the coaxial power supply structure. The release holes are symmetrically arranged about the axis of the coaxial power supply structure, and the cross-section of the release holes is rectangular.

[0011] Furthermore, the opening width of the exponential gradient curve is 0.399 mm at the beginning and 5.488 mm at the end, with a distance of 7.949 mm between the beginning and end.

[0012] Furthermore, the other end of the coaxial inner core is connected to the coaxial connector through a coaxial matching interface. The coaxial matching interface is compatible with the standard connector. At the coaxial matching interface, a cylindrical protrusion is provided on one side of the coaxial inner core, and a semi-circular notch is provided on the coaxial outer conductor corresponding to the side with the cylindrical protrusion.

[0013] Furthermore, the coaxial inner core, coaxial outer conductor, fan-shaped feed, and metal cavity of the coaxial feed structure are all made of copper. The thickness of the coaxial outer conductor and the metal cavity is 0.9 mm, and the thickness of the coaxial inner core and the fan-shaped feed is 0.3 mm.

[0014] Furthermore, the width of the inclined straight slit is equal to the width of the starting end of the exponentially gradient curve opening.

[0015] Furthermore, the metal cavity is a cuboid cavity with a length of 11.65 mm and a width of 14.90 mm, and the radius of the matching circular hole is 0.84 mm.

[0016] Furthermore, the width of the coaxial matching section is smaller than the width of the coaxial inner core. The entire coaxial matching section is located in the metal cavity. The coaxial matching section extends into the fan-shaped feed source by a set length, and the coaxial matching section and the fan-shaped feed source are integrally formed. The fan-shaped angle of the fan-shaped feed source is 90°.

[0017] Furthermore, the comb-shaped slots are symmetrical about the centerline of the metal cavity, and the length of the comb-shaped slots gradually shortens from the fan-shaped feed source to the opening end of the metal cavity.

[0018] On the other hand, the present invention also provides a micro-coaxial ultra-wideband half-mode Vivaldi antenna. Based on the micro-coaxial ultra-wideband Vivaldi antenna described above, the side of the metal cavity without matching circular holes is removed, and the side with the metal cavity removed is set as a grid.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The exponentially tapered aperture and comb-shaped slots improve the bandwidth of the micro-coaxial ultrawideband Vivaldi antenna while maintaining high gain. The exponentially tapered aperture achieves a smooth transition from the feed point to the radiating aperture, reducing reflections and ensuring impedance matching over a wide bandwidth. Electromagnetic waves gradually radiate into free space along the exponentially tapered aperture, forming end-fire radiation with a high gain pattern. The exponential tapering provides continuous phase changes, supporting resonance at multiple frequencies, thereby enabling ultrawideband antenna operation.

[0021] The micro-coaxial ultrawideband Vivaldi antenna described in this invention has a 10-fold operating bandwidth and an impedance bandwidth of approximately 163.64% (S). 11The antenna gain is ≤-10dB, with a frequency range of 10GHz to 100GHz. The antenna gain reaches 4.0dB, 8.2dB, 5.8dB, 7.5dB, 7.5dB, 8.4dB, 8.6dB, 7.6dB, 7.2dB, and 9.0dB at 10GHz, 20GHz, 30GHz, 40GHz, 50GHz, 60GHz, 70GHz, 80GHz, 90GHz, and 1000GHz, respectively. The 9-layer micro-coaxial ultrawideband Vivaldi antenna, fabricated using M-MAM (micro metal additive manufacturing) technology, has a simpler structure, lower loss, and wider bandwidth compared to common microstrip antennas and substrate integrated waveguide antennas.

[0022] Furthermore, the axially periodically arranged SU-8 support structure can construct a quasi-rigid mechanical framework, preventing the metal coaxial core from shifting or deforming due to temperature or humidity changes, mechanical vibration, or other external forces. This ensures that the coaxial core can be processed according to the expected structure. SU-8, a high aspect ratio photoresist material, with its good elastic modulus and low creep characteristics, can effectively disperse nonlinear stresses caused by thermomechanical loads, ensuring sufficient positioning accuracy between the coaxial core and the outer conductor. Its electromagnetic properties, with a dielectric constant close to that of air, can reduce field disturbances of the transmission line's TEM mode by the support unit, while suppressing voltage standing wave ratio degradation caused by interface reflections.

[0023] Furthermore, the release holes serve as etchant diffusion paths in the M-MAM process. Their symmetrical design enables isotropic etching of the polymer matrix, effectively avoiding etching residues caused by closed cavities, and significantly reducing the positional tolerance requirements.

[0024] Furthermore, the thickness of the coaxial inner core and the fan-shaped feed is 0.3 mm, and the wall thickness of the coaxial outer conductor and the metal cavity of the coaxial feed structure is 0.9 mm. This is the standard height for 9-layer micro-coaxial processing, which allows for more uniform electroplating during processing.

[0025] Furthermore, the overall structure of the micro-coaxial Vivaldi antenna is made of copper. The high conductivity of copper effectively reduces ohmic loss. By reasonably designing the angle of the fan-shaped feed, the additional loss caused by the skin effect can be reduced. At the same time, in high-power scenarios, the thermal diffusion capability of copper can ensure that the antenna operates within a safe temperature range.

[0026] Furthermore, the coaxial matching interface has a cylindrical metal protrusion above the coaxial inner core, and the micro coaxial outer conductor above it has a semi-circular metal notch. This structure enables the coaxial feed structure to be matched with the 1mm connector. The width of the coaxial matching section is greater than that of the inner core, forming a stepped impedance transformation structure. The gradual cross-sectional area achieves a smooth transition from the characteristic impedance of the coaxial line to the fan-shaped feed impedance, reducing interface reflection. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, such as changing the power supply interface, changing the number of processing layers and layer height, changing the exponential gradient curve opening, changing the radius of the matching circular hole, changing the operating frequency range, changing the metal cavity size, etc. It is obvious that physical structure and corresponding electrical performance modifications can be made by those skilled in the art.

[0028] Figure 1 The diagram illustrates a three-dimensional structure of a micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention.

[0029] Figure 2 The illustration schematically shows a perspective top view of a micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention;

[0030] Figure 3 The illustration schematically shows a perspective side view of a micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention;

[0031] Figure 4 The schematic diagram illustrates a three-dimensional structure of a micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention.

[0032] Figure 5 The schematic illustration shows a perspective top view of a micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention.

[0033] Figure 6 A perspective side view of a micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention is shown schematically.

[0034] Figure 7 The diagram illustrates the return loss of the micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention as a function of frequency.

[0035] Figure 8The diagram illustrates the return loss of a micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention as a function of frequency.

[0036] Figure 9 The diagram schematically illustrates the YOZ plane radiation patterns of the micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention, with frequencies of 10 GHz (a), 40 GHz (b), 70 GHz (c), and 100 GHz (d).

[0037] Figure 10 The XOZ plane radiation patterns of the micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention are schematically shown, with frequencies of 10 GHz in Figure (a), 40 GHz in Figure (b), 70 GHz in Figure (c), and 100 GHz in Figure (d).

[0038] Figure 11 The diagram schematically illustrates the YOZ plane radiation patterns of the micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention, with frequencies of 10 GHz (a), 40 GHz (b), 70 GHz (c), and 100 GHz (d).

[0039] Figure 12 The XOZ plane radiation patterns of the micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention are schematically shown, with frequencies of 10 GHz in Figure (a), 40 GHz in Figure (b), 70 GHz in Figure (c), and 100 GHz in Figure (d).

[0040] Figure 13 The diagram illustrates the radiation efficiency of the micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention as a function of frequency.

[0041] Figure 14 The diagram illustrates the radiation efficiency of the micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention as a function of frequency.

[0042] Figure 15 The diagram illustrates the maximum gain of the micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention as a function of frequency.

[0043] Figure 16 The diagram illustrates the maximum gain of the micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention as a function of frequency.

[0044] In the attached diagram, 1-coaxial feed structure, 2-fan-shaped feed source, 3-metal cavity, 4-exponentially gradient curved opening, 5-comb-shaped slot, 6-coaxial inner core, 7-coaxial outer conductor, 8-matching circular hole, 9-SU-8 support structure, 10-release hole. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The invention will now be described in further detail with reference to the accompanying drawings.

[0047] This invention discloses a micro-coaxial ultra-wideband Vivaldi antenna and a half-mode Vivaldi antenna, comprising a coaxial feed structure 1, a fan-shaped feed 2, and a metal cavity 3; an exponentially tapered curved opening 4 is formed in the upper part of the metal cavity 3, and comb-shaped slots 5 are formed on both sides of the metal cavity 3; a matching circular hole 8 is formed on the metal cavity 3, located on one side of the connection between the fan-shaped feed 2 and the coaxial inner core 6; an SU-8 support structure 9 is provided in the metal cavity 3 and the coaxial outer conductor 7; and release holes 10 are uniformly arranged on the coaxial outer conductor 7; the coaxial feed structure 1 includes a coaxially arranged... The coaxial feed structure consists of an inner core 6 and a coaxial outer conductor 7. The inner core 6 is suspended inside the outer conductor 7 and connected to the fan-shaped feed 2 via a matching structure. The width of the matching structure is smaller than the width of the inner core 6. The inner core 6 is located on the centerline of the outer conductor 7. The inner core 6 is connected to the outer conductor 7 via an SU-8 support structure 9 and is suspended. The fan-shaped feed 2 is suspended in the metal cavity 3 via the SU-8 support structure 9. A release hole 10 is located on the outer wall of the coaxial feed structure 1. The release hole 10 is a rectangular cross-section release hole and is axially symmetrical about the inner core 6. The fan-shaped feed 2 can smoothly transition the electromagnetic field distribution between the feed point and the gap, reduce impedance abrupt changes, reduce reflection loss, and improve energy transmission efficiency. An exponentially tapered curved opening 4 is formed on the upper part of the metal cavity 3. This opening provides a smooth transition from the feed point to the radiating opening, reducing reflections and ensuring impedance matching over a wide bandwidth. The exponential gradient provides continuous phase change, supporting resonance at multiple frequencies and enabling ultra-wideband antenna operation. Comb-shaped slots 5 are formed on both sides of the metal cavity 3, symmetrical about the centerline. Starting from the end of the fan-shaped feed 2, the length of the comb-shaped slots gradually decreases towards the direction away from the feed 2. These slots not only concentrate the surface current near the exponentially tapered curve, enhancing radiation, but also serve to clean the photoresist during the processing. A matching circular hole 8 is formed at the lower part of the metal cavity 3. This hole connects to the exponentially tapered curved opening 4 via an inclined straight slot. The matching circular hole 8 features an arc transition to optimize impedance matching, suppress high-frequency reflections, and extend the bandwidth.

[0048] refer to Figure 1 and Figure 4 The other end of the coaxial inner core 6 is connected to the coaxial connector through the coaxial matching interface. The coaxial matching interface is compatible with the standard connector. At the coaxial matching interface, a cylindrical protrusion is provided on one side of the coaxial inner core 6, and a semi-circular notch is provided on the coaxial outer conductor 7 corresponding to the side with the cylindrical protrusion.

[0049] Based on the above structure and optimized parameters, the thickness of the SU-8 support structure 9 is h1=0.04mm. The SU-8 support structure 9 is used to support the coaxial inner core 6 and has little impact on the simulation of the micro-coaxial ultra-wideband Vivaldi antenna. The starting width of the exponentially tapered curve opening 4 is W2=0.399mm, the ending width is W4=5.488mm, and the distance between the starting and ending ends is L2=7.949mm. The exponentially tapered curve opening 4 is the core of the ultra-wideband performance of the Vivaldi antenna and has a significant impact on the bandwidth during simulation. The radius of the matching hole 8 is 0.84mm, and the distance between the matching hole 8 and the bottom of the metal cavity 3 is L3=1.715mm, while the distance between the matching hole 8 and the outer wall of the metal cavity 3 closest to it is W3=3.928mm. The matching hole 8 is mainly used to optimize impedance matching and radiation characteristics.

[0050] In the described micro-coaxial ultra-wideband Vivaldi antenna, the excitation signal is input through the coaxial feed structure 1, transmitted via a coaxial line to the fan-shaped feed 2, and radiated outwards along the exponentially tapered curved opening 4. The coaxial inner core 6 has a tapered structure at the connection between the fan-shaped feed 2 and the coaxial feed structure 1, used to achieve broadband impedance matching within the 10-100 GHz range. The use of the exponentially tapered curved opening 4 and the comb-shaped slots 5 not only improves the bandwidth of the micro-coaxial ultra-wideband Vivaldi antenna but also maintains sufficient gain.

[0051] To verify the effectiveness of the aforementioned micro-coaxial ultrawideband Vivaldi antenna and half-mode Vivaldi antenna, the following structural dimensions are used as an example for illustration:

[0052] Please see Figures 1 to 6 , Figure 1 The diagram illustrates a three-dimensional structure of a micro-coaxial ultra-wideband Vivaldi antenna according to an embodiment of the present invention. The micro-coaxial ultra-wideband Vivaldi antenna includes a coaxial feed structure 1, a fan-shaped feed source 2, and a metal cavity 3. An exponentially tapered curved opening 4 is formed in the upper part of the metal cavity 3, and comb-shaped slots 5 are formed on both sides of the metal cavity 3. Matching circular holes 8 are formed in the lower part of the metal cavity 3. The antenna is fabricated using a nine-layer process. Multiple SU-8 support structures 9 are located in the fifth layer of the nine-layer micro-coaxial structure, and multiple release holes 10 are located on the outer wall of the coaxial feed structure 1. Figure 2 and Figure 3The following schematic diagrams illustrate a micro-coaxial ultrawideband Vivaldi antenna according to an embodiment of the present invention, showing a top perspective view and a side view. In the diagrams, the coaxial inner core 6 and the fan-shaped feed 2 have a thickness of h1=0.3mm, the coaxial feed structure 1 and the metal cavity 3 have a thickness of H1=0.9mm, the metal cavity 3 has a length of L1=11.65mm, a width of W1=14.90mm, and a height of H1=0.9mm, and the fan-shaped feed 2 is moved 0.151mm in the direction of the coaxial line, and the fan angle is 90°. Figure 4 The schematic diagram illustrates a three-dimensional structure of a micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention. Figure 5 and Figure 6 The perspective top view and side view of a micro-coaxial ultrawideband half-mode Vivaldi antenna according to an embodiment of the present invention are shown respectively. The half-mode Vivaldi antenna metal cavity 3 has a length of L1=11.65mm and a width of W1 / 2=7.45mm. The side of the metal cavity 3 without matching circular holes 8 is removed, and the side with the removed metal cavity 3 is set as a grid to strengthen the antenna and promote more uniform electroplating during the antenna processing. The comb-shaped slot (5) is symmetrical about the centerline of the metal cavity (3), and the length of the comb-shaped slot (5) gradually shortens from the fan-shaped feed to the opening end of the metal cavity 3.

[0053] Figure 7 and Figure 8 The illustration schematically shows the operating frequency bands of the micro-coaxial ultra-wideband half-mode Vivaldi antenna and the half-mode Vivaldi antenna according to an embodiment of the present invention. The return loss of the micro-coaxial ultra-wideband Vivaldi antenna and the half-mode Vivaldi antenna is greater than 10 dB between 10 GHz and 100 GHz.

[0054] Figure 9 , Figure 10 , Figure 11 and Figure 12 The schematic diagram illustrates the YOZ and XOZ plane radiation patterns of the micro-coaxial ultra-wideband Vivaldi antenna and the half-mode Vivaldi antenna according to embodiments of the present invention at 10 GHz, 40 GHz, 70 GHz, and 100 GHz, wherein... Figure 9 , Figure 10 , Figure 11 and Figure 12 Each includes four sub-figures (a), (b), (c), and (d), which are the YOZ and XOZ plane radiation patterns at 10 GHz, 40 GHz, 70 GHz, and 100 GHz, respectively. As can be seen from the figures, the antenna operates in the frequency band from 10 to 100 GHz, with an antenna bandwidth of approximately 163.64%. The antenna gain is better than 4 dB throughout the entire operating frequency band.

[0055] Figure 13 and Figure 14 The illustration schematically shows the radiation efficiency of the micro-coaxial ultra-wideband half-mode Vivaldi antenna and the half-mode Vivaldi antenna according to an embodiment of the present invention. The radiation efficiency of the micro-coaxial ultra-wideband Vivaldi antenna and the half-mode Vivaldi antenna decreases with increasing frequency and is greater than 91% between 10 GHz and 100 GHz.

[0056] Figure 15 and Figure 16 The illustration shows the maximum gain of the micro-coaxial ultra-wideband half-mode Vivaldi antenna and the half-mode Vivaldi antenna according to an embodiment of the present invention. The maximum gain of the micro-coaxial ultra-wideband Vivaldi antenna and the half-mode Vivaldi antenna is slightly lower in the 10-40 GHz range, and the maximum gain of the antenna is better than 7 dB when the frequency is greater than 40 GHz.

[0057] In summary, this invention discloses a micro-coaxial ultra-wideband Vivaldi antenna and a half-mode Vivaldi antenna. The micro-coaxial ultra-wideband Vivaldi antenna and the half-mode Vivaldi antenna include a coaxial feed section and a wideband Vivaldi antenna section. Specifically, one end of the coaxial feed section is connected to a 1mm connector via a coaxial matching interface, and the other end is connected to the fan-shaped feed of the Vivaldi antenna. The coaxial inner core of the micro-coaxial structure is located at the center of the coaxial feed section, and is equidistant from the upper and lower metal coaxial outer conductors. The coaxial inner core and the fan-shaped feed are connected to the coaxial outer conductor via an SU-8 support structure. The release hole is a rectangular release hole located on the outer wall of the coaxial feed structure and is centrally symmetrical about the coaxial inner core. The wideband Vivaldi antenna section includes a rectangular metal cavity and an exponentially tapered curved opening, a comb-shaped slot, and a matching circular hole at the bottom of the metal cavity. This invention reduces antenna loss through a coaxial structure, enabling the antenna to operate at high frequencies. Furthermore, the Vivaldi antenna achieves wider impedance matching through exponentially tapered curved openings, comb-like slots, and matching circular holes, increasing its bandwidth while maintaining good gain.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A micro-coaxial ultrawideband Vivaldi antenna, characterized in that, It includes a coaxial feed structure (1), a fan-shaped feed (2), and a metal cavity (3); the coaxial feed structure (1) includes a coaxial inner core (6) and a coaxial outer conductor (7). The coaxial inner core (6) is suspended inside the coaxial outer conductor. One end of the coaxial inner core (6) is connected to the fan-shaped feed (2) through a coaxial matching section, and the other end is a free end; the fan-shaped feed (2) is suspended in the metal cavity (3). A matching circular hole (8) is opened on the metal cavity (3) on one side of the fan-shaped feed (2). An exponentially gradient curve opening (4) is opened on the metal cavity (3). The matching circular hole (8) and the exponentially gradient curve opening (4) are connected through an inclined straight gap; comb-shaped gaps (5) are opened on both sides of the metal cavity (3); the metal cavity (3) is connected to the coaxial outer conductor (7).

2. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, In the coaxial power supply structure (1), multiple SU-8 support structures (9) are arranged at intervals along the axial direction. The SU-8 support structure (9) connects the coaxial inner core and the coaxial outer conductor. The SU-8 support structure (9) is made of negative photoresist based on epoxy resin. Release holes (10) are arranged around the coaxial outer conductor of the coaxial power supply structure (1). The release holes (10) are arranged symmetrically about the axis of the coaxial power supply structure (1). The cross section of the release holes (10) is rectangular.

3. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The opening width of the exponential gradient curve (4) is 0.399 mm at the beginning and 5.488 mm at the end, with a distance of 7.949 mm between the beginning and end.

4. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The other end of the coaxial inner core (6) is connected to the coaxial connector through the coaxial matching interface. The coaxial matching interface is matched with the standard connector. At the coaxial matching interface, a cylindrical protrusion is provided on one side of the coaxial inner core (6), and a semi-circular notch is provided on the coaxial outer conductor (7) corresponding to the side with the cylindrical protrusion.

5. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The coaxial inner core (6), coaxial outer conductor (7), fan-shaped feed (2), and metal cavity (3) of the coaxial feed structure (1) are all made of copper. The thickness of the coaxial outer conductor (7) and metal cavity (3) is 0.9 mm, and the thickness of the coaxial inner core (6) and fan-shaped feed (2) is 0.3 mm.

6. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The width of the inclined straight slit is equal to the width of the starting end of the exponentially gradient curve opening (4).

7. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The metal cavity (3) is a cuboid cavity with a length of 11.65 mm and a width of 14.90 mm. The radius of the matching circular hole (8) is 0.84 mm.

8. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The width of the coaxial matching section is smaller than the width of the coaxial inner core (6). The entire coaxial matching section is located in the metal cavity (3). The coaxial matching section extends into the fan-shaped feed (2) by a set length. The coaxial matching section and the fan-shaped feed (2) are integrally formed. The fan-shaped angle of the fan-shaped feed (2) is 90°.

9. The Vivaldi micro-coaxial ultrawideband antenna according to claim 1, characterized in that, The comb-shaped slit (5) is symmetrical about the centerline of the metal cavity (3), and the length of the comb-shaped slit (5) gradually shortens from the fan-shaped feed to the opening end of the metal cavity (3).

10. A micro-coaxial ultrawideband half-mode Vivaldi antenna, characterized in that, Based on the micro-coaxial ultrawideband Vivaldi antenna according to any one of claims 1-9, the side of the metal cavity (3) without the matching circular hole (8) is removed, and the side with the metal cavity (3) removed is set as a grid.

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