A low metal content antenna and its design method

Abstract

The present invention relates to a low-metal antenna and its design method. A carbon powder slurry is applied to the surface of an antenna element to form a carbon powder slurry coating. The antenna element is a semiconductor radiating element. The disclosed antenna proposes a typical alternative material for manufacturing radar antennas, which can reduce the metal content of the radar antenna in a composite mine detector system, thereby effectively reducing the radar antenna's impact on the primary field of the electromagnetic induction module, improving system sensitivity and dynamic range, and achieving beneficial effects in electrical performance, quality, and cost.

Description

Technical Field

[0001] The invention belongs to the field of underground or concealed target detection, and in particular relates to an antenna with low metal content and a design method thereof in this field. Background Art

[0002] The combined mine detector consists of two modules: a low-frequency electromagnetic induction detection module and a high-frequency radar antenna. The basic principle of the low-frequency electromagnetic induction detection module for detecting underground targets is to pass an alternating current of a certain frequency, I1, through a transmitting coil. This generates an alternating magnetic field, B1, of the same frequency (called the primary field) around the transmitting coil. When a metal object is present in the primary field, eddy currents, I2, are induced in the metal object, which in turn induce a magnetic field, B2, around it (called the secondary field). The generation of B2 disrupts the distribution of the primary field, B1. The receiving unit within the low-frequency electromagnetic induction detection module detects this change and generates an electrical signal. Subsequent circuit analysis and processing produce an appropriate alarm signal, thereby determining the presence of a mine. In other words, the low-frequency electromagnetic induction detection module uses the principle of electromagnetic induction to detect metal components within mines, thereby determining the presence of mines or unexploded ordnance (UXO) in underground or concealed areas.

[0003] The primary field B1 generated by the low-frequency electromagnetic induction detection module is severely affected by metal objects and ferromagnetic materials around the transmitting coil. If the detection system itself contains metal or ferromagnetic components, it will seriously affect the detection sensitivity and dynamic range of the system.

[0004] The metal content and caliber of the high-frequency radar antenna itself are far greater than those of modern small mines. Therefore, while the introduction of the high-frequency radar antenna can reduce the system's false alarm probability by detecting differences in dielectric parameters and combining them with image recognition, its modulation of the primary field also seriously affects the dynamic range and sensitivity of the low-frequency electromagnetic induction detection module. Therefore, finding a method to eliminate the impact of the high-frequency radar antenna on the primary field of the low-frequency electromagnetic induction detection module to improve the system's electromagnetic compatibility is one of the keys to ensuring the sensitivity and overall performance of the composite mine detector system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an antenna with low metal content and a design method thereof, which is a radar antenna selection and design method for solving the system compatibility problem of composite mine detectors.

[0006] The present invention adopts the following technical solutions:

[0007] The invention relates to an antenna with low metal content. The improvement thereof lies in that carbon powder slurry is coated on the surface of the antenna vibrator to form a carbon powder slurry coating layer.

[0008] Furthermore, the antenna element is a semiconductor radiation element.

[0009] An antenna design method is used to design the above antenna, wherein the improvement is that it includes the following steps:

[0010] Step 1: Assume that the thickness of the carbon powder slurry coating layer is h, the width of the antenna vibrator is a, the length of the antenna vibrator is d, the DC resistance of the two ends of one arm of the antenna vibrator is R, and the resistivity of the carbon powder slurry is ρ. Then The electrical conductivity of the carbon powder slurry is σ, then σ=1 / ρ;

[0011] Step 2: The DC resistance R and the conductivity σ of the carbon powder slurry are brought into electromagnetic simulation software to perform design and simulation calculations on the form and size of the antenna element;

[0012] Step 3: Divide the antenna element into sections, set different conductivities for each section, and apply carbon powder slurries with different conductivities to different sections, or apply the same carbon powder slurry to different thicknesses in different sections.

[0013] Step 4: Make a cardboard or PCB semiconductor antenna substrate that matches the radar antenna mounting platform structure;

[0014] Step 5: Make the antenna vibrator feeding terminal. Lead out the feeding end by gluing copper foil or PCB metal plating to the central feeding area of ​​the two arms of the antenna vibrator, and fix it with glue in the entire central feeding area of ​​the antenna vibrator.

[0015] Furthermore, in step 3, before applying the carbon powder slurry, a carbon powder slurry coating mold is manufactured according to the contour of the antenna element.

[0016] Furthermore, in step 4, the semiconductor antenna substrate is circular or rectangular.

[0017] The beneficial effects of the present invention are:

[0018] The antenna disclosed in the present invention proposes a typical alternative material for making radar antennas, which can reduce the metal content of the radar antenna of the composite mine detector system, thereby effectively reducing the impact of the radar antenna on the primary field of the electromagnetic induction module, improving the system sensitivity and dynamic range, and having beneficial effects in electrical performance, quality, cost and other aspects.

[0019] The antenna design method disclosed in the present invention is a generalized antenna design and system matching method. The antenna is made of non-metallic materials, and the raw materials used for antenna production are processed by coating carbon powder slurry on ordinary cardboard.

[0020] In terms of system compatibility, the radar antenna is the component with the highest and most concentrated metal content within the composite mine detector, and thus has the greatest impact on the primary field of the low-frequency electromagnetic induction module. Modulating the carbon powder slurry according to the designed conductivity index and applying the slurry to the designed thickness can significantly reduce the metal content of the mine detector system, thereby essentially eliminating the radar antenna's impact on the electromagnetic induction module and improving the detection sensitivity and electromagnetic compatibility of the entire system.

[0021] In terms of radiation efficiency, the antenna made of cardboard coated with carbon powder slurry has a more uniform and smoother characteristic impedance than the conventional small centralized resistive loaded antenna, and has higher radiation efficiency, thereby ensuring that the radio frequency energy output by the radar transmitter is efficiently radiated in the form of electromagnetic waves, thereby improving the detection depth of the radar module.

[0022] In terms of design flexibility, the semiconductor antenna proposed in the present invention can adopt the size and shape design of conventional antennas. Its most outstanding advantage is that it can optimize the antenna matching performance by adjusting the conductivity of the carbon powder slurry and the coating thickness of the carbon powder slurry while keeping the antenna shape and size unchanged, thereby greatly improving the freedom of antenna design in limited space and fixed platform.

[0023] In terms of production cost, the semiconductor material antenna proposed in the present invention uses carbon powder slurry as raw material, and the structural support material can be ordinary cardboard, thin paper or general PCB board. It has low production cost and light weight, is easy to conform to other equipment or platforms, and has extremely low cost-effectiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the relationship between the size of the carbon powder slurry coating layer of the antenna element and the resistivity of the carbon powder slurry;

[0025] Figure 2 It is a schematic diagram of a semiconductor antenna vibrator;

[0026] Figure 3 It is a schematic diagram of the impedance partition adjustment of the antenna element. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] Example 1. This example discloses a low-metal antenna. A non-metallic carbon powder slurry is coated on the surface of the antenna element to form a carbon powder slurry coating. This replaces a metal radar antenna, reducing the metal content of the composite mine detector system and effectively eliminating the unwanted modulation of the primary field of the low-frequency electromagnetic induction module by the metal effect of the radar antenna. The antenna element is a semiconductor radiating element.

[0029] First, the antenna design is optimized based on the operating frequency band of the radar system and the radar antenna mounting platform. The design work in this link is similar to the design method of conventional metal antennas. Conventional antenna design methods and simulation software can be used to establish the antenna model. For precise design, a mounting platform can be added to the model, and the physical size and shape of the antenna can be optimized based on the establishment of the preliminary model. The difference from conventional antenna design is that the setting of the antenna material needs to be set according to the expected electrical parameters of the carbon powder slurry. The electrical parameters of the carbon powder slurry (such as conductivity σ) can also be appropriately adjusted during the design process.

[0030] After the antenna design is finalized, a carbon powder slurry with specific electrical parameters needs to be prepared. During this preparation process, the conductivity of the slurry must be strictly controlled to ensure that the characteristic impedance of the final antenna element remains consistent with the design. To ensure that the electrical parameters of the prepared slurry meet the design expectations, a rectangular strip of a specific size can be applied and resistance tested and adjusted.

[0031] After preparing the toner paste, the antenna element outline can be drawn according to the design results of the first step, and the toner paste can be applied to the cardboard or PCB. This step requires strict application according to the design outline of the first step, while also properly controlling the coating thickness.

[0032] After the semiconductor oscillator coating is completed, a feed terminal must be connected to the center of the antenna element to transmit the high-frequency current output by the transmitter. This can be achieved by bonding copper foil to the center of the oscillator's two arms. After the radar antenna element is designed and fabricated, antenna performance testing can be performed.

[0033] A simple and reliable implementation plan is proposed for the feeding method of non-metallic antennas. This method can effectively feed the radio frequency energy output by the radar transmitter to the non-metallic antenna, and is simple and reliable in engineering implementation.

[0034] This embodiment further discloses an antenna design method for designing the above antenna, comprising the following steps:

[0035] Step 1, such as Figure 1As shown, let the thickness of the carbon powder slurry coating be h, the width of the antenna element be a, the length of the antenna element be d, the DC resistance of the two ends of one arm of the antenna element be R, and the resistivity of the carbon powder slurry be ρ, then The conductivity of the carbon powder slurry is σ, then σ=1 / ρ; based on the above formula, the carbon powder slurry can be prepared and the DC resistance of the coating layer can be tested and adjusted.

[0036] Step 2: Bring the DC resistance R and the conductivity σ of the carbon powder slurry into the electromagnetic simulation software to design and simulate the form and size of the antenna vibrator. Figure 2 It is a semiconductor antenna element designed under the conditions of specific conductivity σ and uniform coating thickness h.

[0037] Step 3: divide the antenna element into zones and set different conductivity for each zone. In the final implementation, it is only necessary to apply carbon powder slurry with different conductivity to different zones, or to apply the same carbon powder slurry with different thicknesses to different zones. Figure 3 This is a schematic diagram of adjusting the antenna element impedance by region. By optimizing and adjusting the antenna element impedance by region, the antenna performance can be further optimized.

[0038] Before applying the carbon powder slurry, a carbon powder slurry coating mold must be made according to the outline of the antenna vibrator. After the outline size of the antenna vibrator is designed, the mold can be easily obtained by turning and milling through an automated machine tool.

[0039] Step 4: Make a cardboard or PCB semiconductor antenna substrate that matches the structure of the radar antenna mounting platform. The semiconductor antenna substrate can be round or rectangular.

[0040] Step 5: Fabricate the antenna element feed terminals. This is accomplished by attaching a small amount of copper foil or PCB metal plating to the central feed area of ​​the antenna element's two arms. To ensure a secure connection, glue the entire central feed area of ​​the antenna element. The glue should be selected to ensure it remains stable within the temperature range of the mine detector's operating environment.

[0041] The method disclosed in this embodiment breaks with the conventional antenna design philosophy of using metal materials such as copper and aluminum, innovatively proposing the use of non-metallic materials to construct radar antennas. Furthermore, based on practical engineering practice, the method further proposes the use of a carbon powder slurry coating as the radar antenna radiator. This essentially eliminates the undesirable modulation of the primary field of the low-frequency electromagnetic induction module by the radar antenna's metal effect, effectively improving the system's electromagnetic compatibility.

[0042] The paper proposes a method and typical steps for designing radar antennas using non-metallic materials, and proposes a method for calculating and testing the electrical parameters of non-metallic coatings, which builds a technical bridge for the application of electromagnetic simulation software in the design of non-metallic antennas and the modulation and testing of non-metallic coating slurries with specific electrical parameters.

[0043] A method for optimizing and adjusting the impedance of non-metallic antenna oscillators by region is proposed. During the design process, this method only requires setting different conductivities for the antenna oscillators in different regions. During implementation, it is only necessary to apply carbon powder slurries with different conductivities according to the designed impedance zones, or to apply the same slurry at different thicknesses. This is a new type of antenna design and implementation method with high efficiency and low cost.

Claims

1. An antenna design method for designing a low-metal-content antenna, wherein carbon powder slurry is coated on the surface of an antenna element to form a carbon powder slurry coating layer; the antenna element is a semiconductor radiating element, characterized in that: The steps include: Step 1: Assume that the thickness of the carbon powder slurry coating layer is h, the width of the antenna vibrator is a, the length of the antenna vibrator is d, the DC resistance of the two ends of one arm of the antenna vibrator is R, and the resistivity of the carbon powder slurry is ρ. Then The electrical conductivity of the carbon powder slurry is σ, then σ=1 / ρ; Step 2: The DC resistance R and the conductivity σ of the carbon powder slurry are brought into electromagnetic simulation software to perform design and simulation calculations on the form and size of the antenna element; Step 3: Divide the antenna element into sections, set different conductivities for each section, and apply carbon powder slurries with different conductivities to different sections, or apply the same carbon powder slurry to different thicknesses in different sections. Step 4: Make a cardboard or PCB semiconductor antenna substrate that matches the radar antenna mounting platform structure; Step 5: Make the antenna vibrator feeding terminal. Lead out the feeding end by gluing copper foil or PCB metal plating to the central feeding area of ​​the two arms of the antenna vibrator, and fix it with glue in the entire central feeding area of ​​the antenna vibrator.

2. The antenna design method according to claim 1, wherein: In step 3, before applying the carbon powder slurry, a carbon powder slurry coating mold is made according to the contour of the antenna element.

3. The antenna design method according to claim 1, wherein: In step 4, the semiconductor antenna substrate is circular or rectangular.

Images