Ultra-wideband multi-section compound disc-cone antenna

Abstract

This invention belongs to the field of communication engineering technology, specifically an ultra-wideband multi-segment composite disc-cone antenna, comprising a radiator assembly, a feed assembly, an impedance matching assembly, and a grounding assembly. The radiator adopts a multi-segment composite structure, with a continuous copper plate conical surface in the low-frequency region and a radial spoke array in the high-frequency region, combined with a multi-layer coaxial disk and an electrically loaded structure. The feed end integrates a stepped impedance transformer and an LC composite matching network, and is equipped with a choke slot to suppress common-mode current. A wide grounding plane is configured at the bottom. By utilizing the segmented tapered surface and spoke array composite structure, the low-frequency continuous current path and the high-frequency discrete current path are separated on the same radiator, avoiding mutual interference between high- and low-frequency electromagnetic behaviors.

Description

Technical Field

[0001] This invention belongs to the field of communication engineering technology, specifically an ultra-wideband multi-segment composite disc-cone antenna. Background Technology

[0002] With the continuous evolution of modern wireless communication and electromagnetic spectrum sensing systems, ultra-wideband antennas, as the core front-end devices for wideband signal reception and radiation, directly determine the system's adaptability to complex electromagnetic environments. In key scenarios such as electromagnetic environment monitoring and radio reconnaissance, the continuous operating bandwidth covering 1.6MHz-6GHz (spanning shortwave, ultra-shortwave, and microwave bands, with a bandwidth ratio as high as 3750:1) has become an important indicator for measuring its comprehensive performance. The physical mechanisms of this frequency band are quite different. The low-frequency band requires sufficient electrical size to achieve effective coupling, while the high-frequency band has stringent requirements for structural precision, mode purity, and impedance stability. How to coordinate the electromagnetic response characteristics of the two on the same physical platform has become a fundamental challenge in the design of ultra-wideband antennas.

[0003] Traditional disk-cone antennas have long been used in broadband applications due to their simple structure, stable radiation pattern, and inherent broadband characteristics. Their typical bandwidth ratio is about 10:1. They rely on the gradual transition between the cone and the disk to achieve smooth impedance changes, but they cannot be adapted to the ultra-wideband of 1.6MHz-6GHz. Low-frequency bands require large size to restrict deployment, while high-frequency bands are prone to exciting high-order surface waves, resulting in radiation pattern distortion and severe impedance fluctuations. Among the existing solutions for extending bandwidth, the multi-layer radiator stacking strategy has the problem of mutual interference between high and low frequencies. Electrical loading technology will reduce high-frequency radiation efficiency, and the mainstream segmented optimized impedance matching network cannot cope with the severe non-monotonic changes in impedance across the entire frequency band.

[0004] Several improved solutions for disc-cone antennas have been disclosed in the relevant technical field:

[0005] The disk-cone antenna disclosed in CN107645037A proposes a structure in which the upper disk and the central body of the cone are tightly fitted by an insulating pad. It utilizes a design that uses short dipoles to correspond to high-frequency bands and long dipoles to correspond to low-frequency bands to achieve bandwidth expansion. Its coaxial feeding method is that the inner conductor is connected to the disk and the outer conductor is connected to the cone. Although this scheme achieves basic high and low frequency partitioning, it uses a solid dipole structure with a fixed cone angle, which is prone to impedance abrupt changes in the frequency band boundary area and cannot cover the 1.6MHz very low frequency band.

[0006] A beamformable disk-cone communication antenna, disclosed in CN113794046B, is designed with a combination of a conical radiator and a disk reflector. It achieves ultra-wideband coverage in the L / S / C bands through a fed balun. However, it does not adopt a composite design of a segmented tapered cone and a spoke array, resulting in limited surface wave suppression in the high-frequency band. It also lacks electrical loading optimization for very low frequencies.

[0007] The disclosed CN111146574B describes a miniaturized disc-cone antenna based on a non-Foster matching circuit. It achieves antenna miniaturization by combining a non-Foster matching circuit with a piecewise linear dipole structure, thus solving the problem of excessive size in the UHF band. However, its matching circuit introduces active devices, which reduces system reliability and does not take into account the stability requirements of the high-frequency radiation pattern.

[0008] The core contradiction of related ultra-wideband disc-cone antennas lies in the irreconcilable physical conflict between the rigid requirement for large electrical size in the low-frequency band and the strict constraints on structural refinement and mode purity in the high-frequency band. Traditional single or simple superposition structural paradigms cannot achieve decoupling and coordinated optimization of high- and low-frequency electromagnetic behavior. Moreover, the overlapping of high- and low-frequency current distributions and the sharing of feed paths mean that local structural adjustments will trigger a chain of disturbances in the electromagnetic response across the entire frequency band, making it difficult to achieve the three major goals of impedance matching, pattern conformal preservation, and size compression simultaneously.

[0009] Therefore, the present invention provides an ultra-wideband multi-segment composite disc-cone antenna. Summary of the Invention

[0010] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0011] The technical solution adopted by this invention to solve its technical problem is as follows: An ultra-wideband multi-segment composite disc-cone antenna, comprising a conical radiating part and a disk-shaped radiating part. The conical radiating part is divided along the axial direction into a low-frequency band region corresponding to 1.6MHz-1GHz and a high-frequency band region corresponding to 1GHz-6GHz. Its geometric shape is a continuously tapered conical structure, with the cone angle gradually decreasing from the bottom to the top, in order to achieve directional guidance and mode control of electromagnetic waves in different frequency bands. The conical surface is not a single continuous metal plate, but rather a composite of a metal plate and a spoke array. In the low-frequency region near the bottom, a continuous conductive surface is formed from a single piece of oxygen-free copper plate, ensuring sufficient electrical dimensions to support effective low-frequency radiation within the 1.6MHz-1GHz frequency band. In the high-frequency region near the top, this is replaced by an open array structure consisting of 5-20 equally spaced radially arranged oxygen-free copper spokes, with a circumferential spacing of 10°-30° between adjacent spokes. This structure maintains pattern stability and mode purity within the 1GHz-6GHz frequency band by suppressing higher-order surface wave excitation and reducing the non-uniformity of high-frequency current distribution. The number, width, and spacing of the spokes are optimized through electromagnetic simulation, ensuring that the high-frequency current primarily flows along the spoke axis, avoiding phase disturbances caused by lateral coupling.

[0012] As a preferred embodiment, the disc-shaped radiating section is positioned directly above the conical radiating section and is electrically isolated and mechanically supported by polytetrafluoroethylene (PTFE) insulators. This disc-shaped radiating section employs a two- or three-layer coaxial nested disc structure, with the diameter of each layer decreasing progressively and maintaining a fixed vertical spacing between them. The bottom large-diameter disc is dedicated to low-frequency radiation in the 1.6MHz-1GHz band, and its edge extends to cover the projected area of ​​the bottom of the cone to enhance low-frequency electric field coupling capability. The upper small-diameter discs are optimized for the 1GHz-6GHz high-frequency band, with their size matching the high-frequency wavelength to effectively suppress high-frequency standing wave spikes and improve radiation efficiency. Each disc layer is made of oxygen-free copper, and its surface is precision-machined to ensure consistent contours. The PTFE insulators are uniformly distributed around the outer edge of the disc, with a dielectric constant of approximately 2.1 and a high-frequency loss tangent of no more than 0.0002, providing reliable mechanical support strength while minimizing the impact of high-frequency dielectric loss on radiation performance.

[0013] As a preferred approach, an electrically loaded structure is integrated at the bottom of the radiating section of the cone. This structure can be either a capacitive loading ring or an inductive loading post inside the cone. When a capacitive loading ring is used, it is a closed metal ring that surrounds and is electrically connected to the outer side of the bottom of the cone. By introducing an equivalent capacitance effect, it extends the low-frequency current path, thereby compressing the physical height required for 1.6MHz to one-third to one-half of that of conventional structures. When an inductive loading post is used, it is one or more metal posts vertically mounted inside the cone cavity, forming a spiral or direct inductive path with the inner wall of the cone, similarly extending the electrical length. Neither loading method introduces additional active components; rather, it enhances low-frequency performance without significantly affecting high-frequency response by changing the local electromagnetic boundary conditions through a passive structure.

[0014] As a preferred embodiment, the feed assembly employs a coaxial feed structure. Its inner conductor extends upwards and is directly welded to the central region of the disk-shaped radiating section, while the outer conductor extends downwards and is fixed to the bottom base of the conical radiating section, thus forming a classic disk-cone feed topology. At the feed point, i.e., the area where the inner and outer conductors intersect, an annular choke groove structure is provided. This groove surrounds the feed port, and its depth and width are determined through electromagnetic field distribution analysis. It is used to suppress common-mode current backflow along the feed line sheath, preventing the external cable from becoming a parasitic radiator and disrupting the radiation pattern symmetry. The feed assembly uses an N-type female connector, which can also be replaced with an SMA connector according to system interface requirements. Both are compatible with 50-ohm characteristic impedance transmission systems, ensuring seamless integration with standard RF links.

[0015] As a preferred approach, the impedance matching component is integrated inside the feed terminal, adjacent to the input port of the coaxial feed structure, and employs a hybrid matching architecture combining a stepped impedance transformer and an LC composite topology. The stepped impedance transformer consists of multiple cascaded microstrip or stripline segments with different characteristic impedances, covering the 100MHz-1GHz mid-frequency band, smoothing the impedance trajectory through a step-by-step transition. The LC network comprises three parts: a series inductor, a parallel capacitor, and a high-frequency microstrip matching stub. The series inductor and parallel capacitor work together in the 1.6MHz-100MHz low-frequency band to compensate for the capacitive reactance deviation introduced by the electrically loaded structure, making the real part of the input impedance approach 50Ω. The high-frequency microstrip matching stub extends to the 4GHz-6GHz high-order frequency band within the 1GHz-6GHz high-frequency band. Its length and terminal load are optimized through full-wave simulation to counteract inductive reflections caused by structural discontinuities in the high-frequency band, effectively suppressing VSWR spikes. The entire matching network is implemented using a multi-layer printed circuit board process, and all component parameters are determined based on full-band S-parameter inversion to ensure that the input VSWR remains below the engineering acceptable threshold throughout the entire 1.6MHz-6GHz range.

[0016] As a preferred embodiment, the grounding assembly is a wide-area grounding plane structure laid beneath the entire bottom of the antenna. It is made of oxygen-free copper or aluminum alloy, and its surface undergoes conductive oxidation treatment to reduce contact resistance. The area of ​​this grounding plane is much larger than the projected area of ​​the radiator, ensuring minimal ground loop inductance in the low-frequency band and providing a stable reference potential for the high-frequency band. The grounding assembly is reliably connected to the feed conductor and the conical base via low-resistance connectors, with an overall grounding resistance not exceeding 1 ohm, thereby ensuring the antenna's operational stability and anti-interference capability in complex electromagnetic environments.

[0017] As a preferred embodiment, the transition region between the conical radiating part and the disk radiating part is provided with a chamfered or arc transition structure. This structure is located at the junction of the top edge of the cone and the inner edge of the bottom disk. The chamfer radius is set between 0.5 mm and 2 mm. By smoothing the geometric abrupt change, the high-frequency electric field concentration is eliminated, and the high-order mode resonance is avoided in the frequency band above 3 GHz, thereby preventing the radiation pattern from splitting or the main lobe shifting.

[0018] As a preferred method, the surface of the conical radiating part is first nickel-plated and then gold-plated. The gold plating layer is 0.05-0.1mm thick and is completed using a vacuum electroplating process to ensure that the plating layer is dense, without pinholes or peeling. This ensures that it maintains excellent conductivity and oxidation resistance under long-term outdoor use conditions, and especially reduces skin effect loss caused by surface roughness in the high-frequency band.

[0019] The beneficial effects of this invention are as follows:

[0020] The ultra-wideband multi-segment composite disk-cone antenna of this invention utilizes a composite structure of segmented tapered conical surfaces and spoke arrays to separate low-frequency continuous current paths and high-frequency discrete current paths on the same radiator, avoiding mutual interference between high- and low-frequency electromagnetic behaviors. Through the synergistic effect of multiple coaxial disks and electrically loaded structures, it maintains effective radiation efficiency in the 1.6MHz band while compressing physical dimensions. It achieves broadband integration of a stepped impedance transformer and an LC composite network at the feed end, actively regulating the input impedance trajectory to the matching region across the entire frequency band. The combined configuration of a ring choke and a wide ground plane effectively suppresses common-mode interference and stabilizes the reference ground potential. Furthermore, through a chamfered transition structure and highly conductive surface treatment, it prevents high-frequency, high-order mode excitation and increased surface loss, thereby maintaining a stable omnidirectional radiation pattern and low VSWR characteristics throughout the 1.6MHz-6GHz frequency band. Attached Figure Description

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] Figure 1 This is a structural block diagram of an ultra-wideband multi-segment composite disc-cone antenna according to the present invention. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0024] like Figure 1 As shown in the embodiment of the present invention, an ultra-wideband multi-segment composite disc-cone antenna comprises four main parts: a radiator assembly, a feed assembly, an impedance matching assembly, and a grounding assembly. The radiator assembly includes a conical radiating part and a disc radiating part, which are arranged along the same axis to form the main radiating structure. The conical radiating part adopts an integrated design of multi-segment composite disc-cone-gradient conical surface-electrically loaded structure. Its geometry is a continuously gradient conical surface structure along the axial direction, with the cone angle gradually decreasing from the bottom to the top, and the cone angle changing from 30° to 10°.

[0025] Specifically, the bottom region has a cone angle of 30°, the middle region transitions to 20°, and the top region converges to 10°. This gradient design is used to directionally guide and control electromagnetic waves of different frequency bands.

[0026] In the low-frequency band region of 1.6MHz-1GHz near the bottom (defined as the range from 0 to 45 mm from the bottom), the conical radiating part is formed by CNC turning of a single piece of oxygen-free copper plate to form a continuous conductive surface. The plate thickness is 2 mm and the surface roughness Ra≤0.8 micrometers to ensure that there are sufficient electrical dimensions in the 1.6MHz-1GHz band to support effective low-frequency radiation.

[0027] In the 1GHz-6GHz high-frequency band region near the top (defined as the range from 0 to 30 mm from the top), the conical radiating section is replaced with an open array structure consisting of 12 equally spaced radially arranged oxygen-free copper spokes. Each spoke is 3 mm wide and 2 mm thick, with a center-to-center spacing of 15° between adjacent spokes, i.e., uniformly distributed circumferentially around a 360° circle. This spoke array structure maintains pattern stability and mode purity in the 1GHz-6GHz band by suppressing higher-order surface wave excitation and reducing the non-uniformity of high-frequency current distribution.

[0028] Electromagnetic simulation results show that when the number of spokes is 12, the width is 3 mm, and the spacing angle is 15°, the surface current in the high-frequency band (≥3 GHz) mainly flows along the spoke axis, and the lateral coupling current component is less than -25 dB, effectively avoiding phase disorder.

[0029] The disc-shaped radiating section is located directly above the conical radiating section and is electrically isolated and mechanically supported by polytetrafluoroethylene insulators. The disc-shaped radiating section adopts a three-layer coaxial nested disc structure, with the diameter of each layer decreasing progressively and maintaining a fixed vertical distance between them. The outer diameter of the bottom large-diameter disc is 180 mm, the outer diameter of the middle layer disc is 120 mm, and the outer diameter of the top small-diameter disc is 60 mm. The thickness of each layer of disc is 1.5 mm. It is made of oxygen-free copper material and precision machined, with the contour tolerance controlled within ±0.05 mm.

[0030] The vertical distance between the bottom disk and the top of the cone is 10 mm, the distance between the middle layer and the bottom layer is 8 mm, and the distance between the top layer and the middle layer is 6 mm. The large-diameter bottom disk is dedicated to low-frequency radiation in the 1.6MHz-1GHz band, and its edge extends to cover the projected area of ​​the bottom of the cone (the diameter of the bottom of the cone is 150 mm) to enhance the low-frequency electric field coupling capability.

[0031] The upper small-diameter disk is optimized for the 1GHz-6GHz high-frequency band. Its size matches the high-frequency wavelength, effectively suppressing high-frequency standing wave spikes and improving radiation efficiency.

[0032] Eight polytetrafluoroethylene (PTFE) insulators are evenly distributed around the outer edge of the disc. Each insulator has an outer diameter of 12 mm, an inner diameter of 6 mm, and a height of 10 mm. Its dielectric constant εr = 2.1 and high-frequency loss tangent tanδ ≤ 0.0002 (test frequency 10 GHz) provide reliable mechanical support strength (compressive strength ≥ 30 MPa) while minimizing the impact of high-frequency dielectric loss on radiation performance.

[0033] An electrical loading structure is integrated at the bottom of the conical radiating section. This structure employs a capacitive loading ring, a closed metal ring formed by bending and welding oxygen-free copper strip. The ring has an outer diameter of 160 mm, an inner diameter of 150 mm, and a thickness of 2 mm. It surrounds the outer side of the conical bottom and is electrically connected to it via laser welding. This structure extends the low-frequency current path by introducing an equivalent capacitance effect, reducing the physical height required for the 1.6 MHz band from approximately 47 meters for a traditional disc-cone antenna to 150 mm (approximately 1 / 315th of the traditional structure), resulting in an actual equivalent electrical length enhancement factor of 3.2 times.

[0034] The equivalent capacitance value was determined to be 18.7pF by full-wave electromagnetic simulation inversion. It generates a capacitive reactance of about 53.2 ohms at 1.6MHz, which forms a partial resonance with the intrinsic inductive reactance of the radiator, thereby significantly improving the low-frequency radiation efficiency.

[0035] The power supply component adopts a coaxial power supply structure. Its inner conductor is an oxygen-free copper rod with a diameter of 2 mm. After extending upwards by 85 mm, it is directly fixed to the central area of ​​the radiating part of the disk by electron beam welding.

[0036] The outer conductor is an oxygen-free copper tube with a diameter of 10 mm. After extending downwards for 60 mm, it is fixed to the bottom base of the conical radiating part through a double process of thread crimping and soldering, thus forming a classic disc-cone feeding topology.

[0037] At the feed point, i.e. the area where the inner and outer conductors meet, an annular choke groove structure is set up. The groove surrounds the feed port, with a depth of 3 mm and a width of 2 mm. The bottom of the groove is 5 mm away from the feed end face. Its geometric parameters are determined by finite-difference time-domain (FDTD) electromagnetic field distribution analysis. It is used to generate a high impedance path in the frequency band above 100 MHz and suppress the common-mode current from flowing back along the outer sheath of the feed line.

[0038] Measurements show that the choke can achieve a common-mode current suppression ratio of -28dB at 1 GHz and maintain it above -22dB at 6 GHz.

[0039] The power supply component has an N-type female connector, with its inner conductor connected to the coaxial inner conductor and its outer conductor shell fixed to the coaxial outer conductor. The whole system is compatible with a 50-ohm characteristic impedance transmission system.

[0040] The impedance matching component is integrated inside the feed terminal, adjacent to the input port of the coaxial feed structure, and adopts a hybrid matching architecture combining a stepped impedance transformer and an LC composite topology. This matching component is implemented using a four-layer high-frequency printed circuit board (FR-4 substrate, dielectric constant εr=4.4, loss tangent tanδ=0.02), with a board thickness of 1.6 mm and a copper foil thickness of 35 micrometers.

[0041] The stepped impedance transformer consists of three cascaded microstrip lines with characteristic impedances of 75 ohms, 60 ohms and 50 ohms respectively. The length of each segment is one-quarter of the wavelength of the corresponding center frequency (300MHz, 600MHz, 900MHz), which is 250mm, 125mm and 83mm respectively, covering the mid-frequency band of 100MHz-1GHz. The impedance trajectory is smoothed through a step-by-step transition.

[0042] The LC network consists of three parts: a series inductor L1, a parallel capacitor C1, and a high-frequency microstrip matching stub. The series inductor L1 is a hollow inductor wound on a high-frequency magnetic core (NiZn ferrite, μr=125) with an inductance of 2.8μH. Together with the parallel capacitor C1 (a ceramic capacitor with a capacitance of 470pF and a quality factor Q value greater than 1000 measured at 100MHz), it works in the low-frequency band of 1.6MHz-100MHz to compensate for the capacitive reactance deviation introduced by the electrically loaded structure.

[0043] The high-frequency microstrip matching stub is an open-circuit microstrip line with a length of 12.5 mm and a 50-ohm resistor as the terminal load. Its position and length are optimized by full-wave simulation and are used to cancel the inductive reflection caused by structural discontinuities in the 4GHz-6GHz high-order frequency band in the 1GHz-6GHz high-frequency band.

[0044] The S-parameters of the entire matching network were measured and verified by a vector network analyzer (Keysight PNAN5227B). The input standing wave ratio (VSWR) was less than 2.5 in the entire frequency band from 1.6MHz to 6GHz, and VSWR was less than 1.8 in the range of 100MHz to 5GHz.

[0045] The grounding component is a wide grounding plane structure, laid under the entire bottom of the antenna. It is made of oxygen-free copper plate with a thickness of 3 mm and an area of ​​600 mm × 600 mm, which is much larger than the maximum projected area of ​​the radiator (diameter 180 mm, area of ​​approximately 25,400 square millimeters).

[0046] The grounding plane surface undergoes conductive oxidation treatment (forming a Cu2O film layer with a thickness of approximately 0.5 micrometers), resulting in a contact resistivity of less than 1.7 × 10⁻⁶. -8 Ω·m. The grounding assembly is reliably connected to the feed conductor and the conical base via four tin-plated copper braided strips with a cross-sectional area of ​​10 square millimeters. The length of each braided strip does not exceed 50 millimeters. The overall grounding resistance was measured to be 0.68 ohms by a milliohm meter (Hioki RM3548), which meets the design requirement of not more than 1 ohm, thereby ensuring the antenna's working stability and anti-interference capability in complex electromagnetic environments.

[0047] The transition area between the conical radiating section and the disk radiating section features a chamfered structure. This chamfer is located at the junction of the top edge of the cone and the inner edge of the bottom disk, with a chamfer radius of 1.2 mm. This geometric transition is precision milled using a five-axis CNC machining center, achieving a surface roughness Ra ≤ 0.4 micrometers. This chamfered structure effectively smooths the geometric abrupt change between high-frequency and low-frequency radiators, eliminating high-frequency electric field concentration.

[0048] Full-wave simulations show that, without chamfering, a significant electric field intensity peak appears at 3.8 GHz (the local field strength reaches 4.2 times that of the incident field), which excites TM. 11 Higher-order mode resonances cause the main lobe of the radiation pattern to split;

[0049] With a 1.2 mm chamfer, the peak electric field at that frequency drops to 1.8 times, higher-order mode resonances are completely suppressed, and the radiation pattern maintains the omnidirectional characteristics of a single main lobe.

[0050] Furthermore, the surface of the radiating part of the cone is first nickel-plated and then gold-plated. The nickel plating layer is 5 micrometers thick and is applied using Watt's nickel electroplating process. The gold plating layer is 0.06 millimeters (60 micrometers) thick and is applied using a cyanide gold plating process in a vacuum electroplating bath at a current density of 2 A / dm², a temperature of 65°C, and a time of 120 minutes. The coating was inspected by scanning electron microscopy (SEM) and found to be dense, without pinholes or peeling, with a porosity of less than 0.5 particles / cm².

[0051] The surface roughness, measured by a white light interferometer, is Ra = 0.12 micrometers, significantly lower than the Ra = 0.85 micrometers of the unplated surface. This high-conductivity surface treatment effectively reduces ohmic losses caused by the skin effect at high frequencies. According to the skin depth formula:

[0052] ,

[0053] in, Indicates skin depth (unit: meter). The resistivity of the material (unit: Ω·m). Frequency (unit: Hz) H / m is the permeability of free space. This represents the relative permeability (1 for copper). For oxygen-free copper ( (Ω·m), with a theoretical skin depth of 0.82 micrometers at 6 GHz;

[0054] Gold plating ( While its Ω·m (dimethylamine) is slightly higher than that of copper, its chemical stability is excellent. Under long-term outdoor use, the oxide layer thickness on its surface can be controlled to within 1 nanometer, whereas bare copper can have an oxide layer exceeding 50 nanometers under the same conditions, leading to a reduction in the effective conductive cross-section. Actual measurements show that the radiation efficiency of the gold-plated antenna at 6 GHz is 3.2 dB higher than that of the untreated prototype.

[0055] Example 1: It adopts all the above technical features, including a three-layer disk, 12 spokes, a capacitive loading ring, a stepped + LC hybrid matching network, 1.2 mm chamfering and gold plating.

[0056] Example 2: The disk body is changed to a two-layer structure (outer diameter 180 mm and 80 mm), the number of spokes is increased to 16, the width is reduced to 2.5 mm, and an inductive loading column (a single copper column with a diameter of 4 mm and a height of 40 mm, placed in the center of the cone cavity) is used. In the matching network, only the series inductor (3.5 μH) is retained in the LC part, the parallel capacitor is eliminated, the chamfer radius is 0.8 mm, and the surface is only plated with nickel (10 micrometers).

[0057] Example 3: The low-frequency region of the cone adopts a slotted continuous plate (slot width 1 mm, spacing 5 mm), the high-frequency region has 8 spokes with a width of 4 mm, the electrical load adopts a composite structure of capacitive ring and inductive column, the matching network adopts a pure stepped impedance transformer (four segments: 80 / 65 / 55 / 50 ohms), without chamfering, and the surface is gold-plated with a thickness of 0.05 mm.

[0058] Comparative Example 1: The radiator is a combination of a traditional single-segment solid cone (cone angle 20°, height 150 mm) and a single-layer disk (diameter 180 mm), without electrical loading, without spoke structure, without choke slot at the feed point, and the matching network contains only a simple LC circuit (L=2μH, C=300pF), without chamfers, and the surface is untreated.

[0059] Comparative Example 2: The cone adopts a full-spoke structure (12 spokes, 150 mm in total length), with no low-frequency continuous plate area, no electrical load, three-layer disks but random spacing (12 / 5 / 10 mm), the matching network lacks high-frequency microstrip branches, and the ground plane area is only 200×200 mm.

[0060] Comparative Example 3: The structure of Example 1 is adopted, but the impedance matching component is removed, and only the coaxial feed is retained, while the rest of the structure remains unchanged.

[0061] All prototypes were tested in a microwave anechoic chamber using a standard gain horn antenna as a reference. A vector network analyzer was calibrated to the feed port, with a radiation pattern measurement step of 5° and a frequency scan step of 10 MHz. Key performance data are shown in the table below:

[0062] Prototype number Frequency band (MHz) Average VSWR Radiative efficiency (dB) at 1.6 MHz 3GHz pattern symmetry error (dB) 6GHz main lobe width (°) Full-band pattern stability Example 1 1.6-6000 1.92 -18.3 ±0.8 78 Excellent (no splitting) Example 2 1.6-6000 2.15 -19.1 ±1.2 82 good Example 3 1.6-6000 2.38 -17.6 ±1.5 85 Acceptable Comparative Example 1 1.6-6000 4.76 -32.5 ±3.5 95 (split) Difference Comparative Example 2 1.6-6000 3.82 -28.7 ±2.8 90 (slight split) Poor Comparative Example 3 1.6-6000 5.13 -25.4 ±2.1 88 Severe mismatch in mid-to-low frequencies

[0063] Among them, the pattern symmetry error is defined as the absolute value of the difference between the maximum gain and the minimum gain in the azimuth plane (φ=0° to 360°); the stability of the full-band pattern is determined by visual evaluation and 3D pattern cross-polarization ratio (XPD), and XPD>15dB is considered stable.

[0064] Furthermore, thermal-electric coupling simulation was performed on Example 1 to evaluate the performance stability under high power.

[0065] Assuming an input power of 100 watts continuous wave, an ambient temperature of 25°C, and a wind speed of 1 m / s, the heat conduction equation is:

[0066] ,

[0067] in, Material density (unit: kg / m³) 3 ), Specific heat capacity at constant pressure (unit: J / (kg·K)) Temperature field (unit: K). Time (unit: seconds) Thermal conductivity (unit: W / (m·K)) External heat source term (unit: W / m) 3 );

[0068] For oxygen-free copper kg / m 3 , J / (kg·K), W / (m·K); for polytetrafluoroethylene kg / m 3 , J / (kg·K), W / (m·K). Calculated from Joule heating:

[0069] ,

[0070] in, Electrical conductivity (unit: S / m) The electric field strength is expressed in V / m. Simulation results show that, with an input power of 100 watts, the highest steady-state temperature occurs near the feed point at 48.3℃, which is far below the glass transition temperature of polytetrafluoroethylene (126℃). The structure has no risk of thermal deformation, and the radiation performance drift is less than 0.5 dB.

[0071] In addition, parameter sensitivity analysis was performed on the impedance matching network of Example 1;

[0072] The tolerance of key components in the matching network is defined as ±5%. Monte Carlo simulation is run 1000 times to count the percentage of frequency points with VSWR > 2.5.

[0073] The results show that, in the range of 1.6MHz-6GHz, 99.2% of the simulation samples satisfy VSWR<2.5, indicating that the matching network of the present invention has good engineering robustness.

[0074] In summary, this invention achieves low VSWR, high efficiency, and stable omnidirectional radiation performance in the 1.6MHz-6GHz ultra-wideband frequency range through a segmented composite structure of the radiator, synergy between multi-layer disks and electrical loading, hybrid impedance matching, joint configuration of choke slots and wide ground planes, and refined geometric transitions and surface treatments. The various technical features work together to solve the long-standing technical problems of weak low-frequency radiation, high-frequency pattern distortion, and impedance mismatch across the entire frequency band in ultra-wideband disk-cone antennas.

[0075] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ultra-wideband multi-section compound disc-cone antenna, characterized in that, This includes radiator components, power supply components, impedance matching components, and grounding components; The radiator assembly includes a conical radiator and a disk-shaped radiator arranged coaxially. The conical radiating part is divided into a low-frequency band corresponding region and a high-frequency band corresponding region along the axial direction. Its geometric shape is a continuously gradually changing conical surface structure, with the cone angle gradually decreasing from the bottom to the top. In the low-frequency band region, a continuous conductive surface is formed by a single piece of metal plate, and in the high-frequency band region, it is replaced by an open array structure composed of 5-20 equally spaced radially arranged metal spokes, with a circumferential spacing of 10°-30° between adjacent spokes. The disc-shaped radiating part is located directly above the conical radiating part, and is electrically isolated and mechanically supported by polytetrafluoroethylene insulators. It adopts a two- or three-layer coaxial nested disc structure, with the diameter of each disc decreasing layer by layer. The bottom large-diameter disc is used for low-frequency radiation of 1.6MHz-1GHz, and the upper small-diameter disc is used for high-frequency radiation of 1GHz-6GHz. The power supply component adopts a coaxial power supply structure, with its inner conductor connected to the central region of the disk-shaped radiating part and its outer conductor connected to the bottom base of the conical radiating part. An annular choke groove structure is provided at the power supply point. The impedance matching component is integrated inside the feed end and adopts a hybrid matching architecture that combines a stepped impedance transformer and an LC composite topology. The stepped impedance transformer covers the 100MHz-1GHz mid-frequency band, and the LC network includes series inductors and parallel capacitors for compensation in the 1.6MHz-100MHz low-frequency band, as well as high-frequency microstrip matching stubs for canceling inductive reflections in the 4GHz-6GHz high-order frequency band of the 1GHz-6GHz high-frequency band. The grounding component is a wide grounding plane laid below the bottom of the antenna, and is connected to the feed conductor and the conical base through a low-resistance connector.

2. The ultra-wideband multi-section compound disc-cone antenna of claim 1, wherein, The conical radiating part is integrally formed from oxygen-free copper sheet. The high-frequency band region is composed of several equally spaced, radially arranged oxygen-free copper spokes.

3. The ultra-wideband multi-segment composite disk-cone antenna according to claim 1, characterized in that, The radial portion of the disk body is a three-layer coaxial nested disk structure; The edge of the bottom disk covers the projection area of ​​the bottom of the cone to adjust the low-frequency electric field coupling capability.

4. The ultra-wideband multi-segment composite disk-cone antenna according to claim 1, characterized in that, The bottom of the conical radiating section is integrated with an electric loading structure, which is a capacitive loading ring or an inductive loading column inside the cone. The capacitive loading ring surrounds and is electrically connected to the outer side of the bottom of the cone to introduce an equivalent capacitance effect to extend the low-frequency current path; The inductive loading column is a metal column that is vertically installed in the inner cavity of the cone, forming an inductive path with the inner wall to achieve an extension of the equivalent electrical length.

5. The ultra-wideband multi-segment composite disk-cone antenna according to claim 4, characterized in that, The capacitive loading ring is made of oxygen-free copper strip and is fixed to the bottom of the cone by laser welding.

6. The ultra-wideband multi-segment composite disk-cone antenna according to claim 1, characterized in that, The annular choke structure surrounds the feed port and is used to suppress common-mode current backflow along the feed line sheath in the frequency band above 100 MHz.

7. The ultra-wideband multi-segment composite disc-cone antenna according to claim 1, characterized in that, The impedance matching component includes a multilayer printed circuit board; The series inductor in the LC network is wound on a NiZn ferrite core and connected in parallel with a ceramic capacitor; the high-frequency microstrip is a matched stub open-circuit microstrip line.

8. The ultra-wideband multi-segment composite disk-cone antenna according to claim 1, characterized in that, The transition region between the conical radiating part and the disk radiating part is located at the junction of the top edge of the cone and the inner edge of the bottom disk.

9. The ultra-wideband multi-segment composite disk-cone antenna according to claim 1, characterized in that, The surface of the radiating part of the cone is first nickel-plated and then gold-plated. The gold plating layer is 0.05-0.1 mm thick and is completed using a vacuum electroplating process.

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