A kind of ultra-wideband small radio frequency antenna for PE pipe detection

Abstract

The application discloses a kind of ultra-wideband small radio frequency antennas for PE pipe detection, it is related to antenna technical field;The application includes insulating dielectric substrate and the radiation structure of setting in insulating dielectric substrate front, the radiation structure includes the main radiation patch of being formed by exponential gradually changing slot line, ring patch is arranged at the end of main radiation patch interval, and strip patch is arranged at interval with ring patch;Resistance element includes first resistance, second resistance and third resistance, and main radiation patch is connected with ring patch by first resistance;The radiation part of the antenna of the application forms specific resistance loading network by radiation structure and resistance element, slot line feed structure feeds energy, and can effectively stimulate lower frequency resonance, reduce the low frequency cutoff frequency of antenna, which is crucial for detecting deep targets, so that the input impedance of the antenna is very stable throughout the ultra-wide frequency band, ensuring energy transmission efficiency, antenna gain and efficiency are gradually increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, in particular to a kind of ultra-wideband small radio frequency antenna for PE pipe detection. BACKGROUND

[0002] With the continuous advancement of urbanization, the types and scale of urban underground pipelines are expanding, and various pipelines are crisscrossed and multi-layered distributed, among which, PE pipes have become widely used pipe materials in municipal engineering such as urban water supply and heating due to their advantages of corrosion resistance, high temperature resistance, low cost, strong stability and convenient installation, etc. However, in the early urban construction, the PE pipes laid often have difficulties in accurate determination of buried position due to incomplete data records, missing drawings or non-standard management, which brings significant difficulties to subsequent engineering planning, construction and maintenance. In order to realize accurate identification of buried depth and position of underground PE pipelines, it is an urgent need to develop an efficient and reliable non-destructive testing technology.

[0003] Ground penetrating radar (GPR) is one of the mainstream detection technologies, and its performance largely depends on the design of antenna. As a key component for transmitting and receiving electromagnetic waves in the system, the antenna must have excellent radiation directivity, high gain and ultra-wideband characteristics to ensure the identification accuracy and detection depth of underground targets. However, the antennas equipped in traditional ground penetrating radar systems often have problems such as large size and limited bandwidth, especially when detecting PE pipes buried more than 2 meters deep, the resolution and positioning accuracy are significantly reduced. In addition, such antennas usually have poor portability and high cost, which limits their widespread application in practical engineering. Therefore, developing a new type of antenna with wide bandwidth, high performance, miniaturization and controllable cost is of great engineering significance and practical value to improve the detection capability of underground PE pipelines. Since common underground pipelines are distributed at about 1.6m, the detection depth of traditional ground penetrating radar antennas is generally within 2 meters, but for some deeply buried pipelines, the specific position cannot be detected. Therefore, in order to achieve deeper detection distance and miniaturization of detection antenna, there is an urgent need for a scheme that can realize antenna design miniaturization and wideband under the condition of ensuring antenna operation at low frequency. Therefore, the present application proposes an ultra-wideband small radio frequency antenna for PE pipe detection to improve the problem. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the present application provides an ultra-wideband small radio frequency antenna for PE pipe detection.

[0005] In order to achieve the above-mentioned purpose, the radio frequency antenna disclosed by the present application can adopt the following scheme:

[0006] The application discloses a kind of ultra-wideband small radio frequency antennas for PE pipe detection, including insulating medium substrate and the radiation structure being arranged at the front of insulating medium substrate, the radiation structure includes the main radiation patch of exponential variation slot line, annular patch being arranged at the end of main radiation patch interval, and strip patch being arranged at annular patch interval;

[0007] Resistance element, including first resistance, second resistance and third resistance, main radiation patch is connected with annular patch by first resistance, and the first end and the last end of annular patch are connected by second resistance, so that annular patch forms a closed loop structure loaded with resistance, and annular patch is connected with strip patch by third resistance;

[0008] Slot line feed structure is arranged on insulating medium substrate, which overlaps the starting end of exponential variation slot line in spatial position, and feeds energy to main radiation patch by electromagnetic coupling mode.

[0009] Further, the slot line feed structure includes a circular short-circuit resonant cavity arranged at the starting end of the exponential variation slot line, and a microstrip line is arranged on the back of the insulating medium substrate, and a fan-shaped open-circuit stub is configured at the end of the microstrip line, and the circular short-circuit resonant cavity and the fan-shaped open-circuit stub are oppositely arranged in space.

[0010] Further, a semi-elliptical matching groove is etched on the main radiation patch and located on both sides of the circular short-circuit resonant cavity.

[0011] Further, a plurality of periodically arranged circular grooves are etched on both side edges of the exponential variation slot line of the main radiation patch.

[0012] Further, a zigzag meander structure is etched at the ends of both side edges of the exponential variation slot line of the main radiation patch.

[0013] Further, a group of rectangular circular arc grooves and a group of rectangular grooves are etched on both sides of the exponential variation slot line of the main radiation patch.

[0014] Further, the circular grooves, the rectangular circular arc grooves, and the rectangular grooves are filled with dielectric materials with a higher dielectric constant than the insulating medium substrate.

[0015] Further, a plurality of wings are connected to the strip patch, the wings are configured in an L shape, having a horizontal connection part coplanar with the strip patch and a vertical radiation part perpendicular to the surface of the insulating medium substrate.

[0016] Further, a mounting flange is arranged on the insulating medium substrate and located at the radiation opening end of the exponential variation slot line, a sleeve is arranged on the mounting flange, and an inner tube is closely and slidingly inserted into the sleeve.

[0017] Further, the protective shell is provided with the radio frequency connector, and the internal contact of the radio frequency connector is connected with the starting end of the microstrip line.

[0018] Compared with the prior art, some beneficial effects of the technical scheme of the present application include:

[0019] 1. In the present application, the radiation part of the antenna forms a specific resistance loading network through the radiation structure and the resistance element, and the slot line feeding structure feeds energy, which can effectively excite resonance at a lower frequency, reduce the low-frequency cutoff frequency of the antenna, is crucial for detecting deep targets, and makes the input impedance of the antenna very stable throughout the ultra-wide frequency band, ensuring energy transmission efficiency, and gradually increasing the antenna gain and efficiency.

[0020] 2. In the present application, the triple lumped resistance element loading effectively improves the impedance matching of the low-frequency band by absorbing the end reflection, widens the cutoff frequency, the first resistance absorbs the excess energy at the end of the antenna, which is absorbed and transmitted to the ring-shaped patch for radiation, the second resistance is connected at the head and tail of the ring-shaped patch to reduce the influence of current backflow, and the third resistance radiates the excess energy in the ring-shaped patch again to reduce the reflection at the low-frequency end and improve the low-frequency characteristics.

[0021] 3. In the present application, two different rectangular grooves are etched in the main radiation part, the etching of short and narrow rectangular grooves and wide and long rectangular arc grooves weakens the backflow strength of the edge of the main radiation patch, enhances the current strength near the exponential line of the patch, and cooperates with the triangular etching at the end of the antenna to effectively extend the effective path of the current. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only represent some embodiments of the present application, and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 is a perspective view of the present application.

[0024] Figure 2 is a perspective view of the present application.

[0025] Figure 3 is a perspective view of part of the structure of the present application.

[0026] Figure 4 is a perspective view of part of the structure of the present application.

[0027] Figure 5 This is a partial planar front view of the structure of this invention.

[0028] Figure 6 This is the present invention. Figure 2 Enlarged view of point A in the middle.

[0029] Reference numerals: 1. Insulating dielectric substrate; 2. Radial structure; 3. Resistor element; 4. Slotted wire feeding structure; 5. Semi-elliptical matching slot; 6. Circular slot; 7. Sawtooth meandering structure; 8. Rectangular arc slot; 9. Rectangular slot; 10. Dielectric material; 11. Wing; 12. Mounting flange; 13. Sleeve; 14. Inner tube; 15. Protective housing; 16. Elastic damping adhesive; 17. RF connector; 201. Main radiating patch; 202. Annular patch; 203. Strip patch; 301. First resistor; 302. Second resistor; 303. Third resistor; 401. Circular short-circuit resonant cavity; 402. Microstrip line; 403. Fan-shaped open-circuit stub. Detailed Implementation

[0030] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this embodiment.

[0031] In view of the many defects existing in the prior art, the following embodiments are optimized and overcome the defects existing in the prior art.

[0032] Example

[0033] like Figures 1-6 As shown, in one embodiment of the present invention, an ultra-wideband miniature radio frequency antenna for PE tube detection is proposed, comprising an insulating dielectric substrate 1 and a radiating structure 2 disposed on the front side of the insulating dielectric substrate 1. Preferably, the insulating dielectric substrate 1 is made of FR4 epoxy resin composite material. The radiating structure 2 includes a main radiating patch 201 formed by exponentially graded groove lines, an annular patch 202 spaced apart from the end of the main radiating patch 201, and a strip patch 203 spaced apart from the annular patch 202. A thin layer of electrolytic copper foil is covered on the front side of the insulating dielectric substrate 1. The designed circuit pattern (including exponentially graded groove lines, annular patch 202 and strip patch 203) is transferred onto the copper foil by photolithography. Then, chemical etching is performed to etch away the unwanted copper. The etched area exposes the insulating dielectric substrate 1 below. The exponentially graded groove lines form the main radiating patch 201, and the retained area constitutes the annular patch 202, the strip patch 203 and a large area of ​​metal ground layer.

[0034] The resistance element 3 includes a first resistance 301, a second resistance 302 and a third resistance 303. The main radiation patch 201 is connected with the ring patch 202 through the first resistance 301. The first end and the second end of the ring patch 202 are connected through the second resistance 302, so that the ring patch 202 forms a closed loop structure loaded with resistance. The ring patch 202 is connected with the strip patch 203 through the third resistance 303. The pads and connection wires for soldering the resistances are etched on the insulating medium substrate 1. Through the full-automatic SMT (Surface Mount Technology) process, the main radiation patch 201, the ring patch 202 and the strip patch 203 are sequentially connected in the form of soldering on the copper foil pads designed in advance in the etching stage, so as to form a specific resistance loading network.

[0035] The slot line feeding structure 4 is arranged on the insulating medium substrate 1 and overlaps the starting end of the exponentially tapered slot line in the spatial position, and feeds energy to the main radiation patch 201 through electromagnetic coupling. The slot line feeding structure 4 feeds energy to the main radiation patch 201 through electromagnetic coupling. The electromagnetic wave excited in the form of a traveling wave propagates from the narrow end to the wide end along the exponentially tapered slot line. The first resistance 301 is responsible for discharging the residual energy at the end of the main radiator to the ring patch 202. The second resistance 302 makes the ring patch 202 itself a closed loop that consumes energy, further consuming energy. The third resistance 303 couples the final energy to the strip patch 203 for the last radiation. It can effectively reduce the end reflection of the antenna, reduce the current flowing back to the feed point, improve the low-frequency impedance matching, at the same time, it can extremely effectively widen the low-frequency bandwidth, especially it can lower the low-frequency cutoff frequency of the antenna, which is crucial for detecting deep targets, and significantly suppresses the adverse reflection caused by mismatch at the end of the structure, so that the input impedance of the antenna is very stable in the entire ultra-wide frequency band, ensuring the energy transmission efficiency, and the antenna gain and efficiency are also gradually increased.

[0036] In the present scheme, the radiation part of the antenna forms a specific resistance loading network through the radiation structure 2 and the resistance element 3, and the slot line feeding structure 4 feeds energy, which can effectively excite lower frequency resonance, lower the low-frequency cutoff frequency of the antenna, which is crucial for detecting deep targets, so that the input impedance of the antenna is very stable in the entire ultra-wide frequency band, ensuring the energy transmission efficiency, and the antenna gain and efficiency are also gradually increased.

[0037] As Figure 3 and Figure 4As shown in the figure, the specific structure of the slot line feed structure 4 of the application is disclosed, which includes a circular short-circuit resonant cavity 401 arranged at the starting end of the exponentially tapered slot line, a microstrip line 402 arranged on the back of the dielectric substrate 1, and a fan-shaped open-circuit stub 403 constructed at the end of the microstrip line 402. The circular short-circuit resonant cavity 401 and the fan-shaped open-circuit stub 403 are oppositely arranged in space. A thin electrolytic copper foil is covered on the back of the dielectric substrate 1, and the microstrip line 402 and the fan-shaped open-circuit stub 403 are formed by photoetching. The circular short-circuit resonant cavity 401 is usually short-circuited by a metallized via hole (first drilled, and then the hole wall is metallized by electroplating process). The radio frequency signal is input from the starting end of the microstrip line 402, and the signal propagates along the microstrip line 402 to the fan-shaped open-circuit stub 403 at the end. Through electromagnetic field coupling, the energy passes through the dielectric substrate 1 to excite the slot line mode at the circular short-circuit resonant cavity 401 on the front side, completing the conversion from the unbalanced transmission line to the balanced transmission line. Through the cooperative design of the circular short-circuit resonant cavity 401 (front side) and the fan-shaped open-circuit stub 403 (back side), efficient coupling and mode conversion from the unbalanced microstrip line 402 to the balanced slot line are realized, and good impedance matching is provided to ensure that the antenna can work stably in the ultra-wideband frequency band.

[0038] As shown in the figure, Figure 3 and Figure 5 Further technical solutions of the application for the main radiation patch 201 are disclosed, and half-elliptical matching grooves 5 are etched on both sides of the circular short-circuit resonant cavity 401 on the main radiation patch 201. By etching the half-elliptical matching grooves 5, they can be used as fine tuning knobs to locally and finely adjust the electromagnetic field of the most critical region of the feed point, realize deep optimization of the standing wave ratio, and ensure smooth and unobstructed energy inlet.

[0039] As shown in the figure, Figure 3 and Figure 5 Further technical solutions of the application for the main radiation patch 201 are disclosed, and a plurality of periodically arranged circular grooves 6 are etched on the edges of the exponentially tapered slot line of the main radiation patch 201. By etching the periodically arranged circular grooves 6, the current slows down when flowing through these periodic structures, producing a significant slow wave effect, reducing the phase velocity, and equivalent to increasing the electrical length, achieving resonance at a lower frequency without changing the physical size, i.e. miniaturization.

[0040] As shown in the figure, Figure 5 Further technical solutions of the application for the main radiation patch 201 are disclosed, and sawtooth-shaped meander structures 7 are etched at the ends of the exponentially tapered slot line on both sides of the main radiation patch 201. By etching the sawtooth-shaped meander structures 7, a bent current path is formed in physics, directly increasing the distance of the current flow, further extending the electrical length and reducing the resonant frequency, thereby improving the practicability.

[0041] As Figure 3 and Figure 5 shown, the application discloses further technical solutions for the main radiation patch 201, and a group of rectangular circular arc grooves 8 and a group of rectangular grooves 9 are etched on both sides of the exponentially tapered slot line of the main radiation patch 201. Preferably, the rectangular circular arc groove 8 is long and wide, and one end is configured with a circular arc. The rectangular groove 9 is short and narrow. The two groups of grooves of different shapes can disturb the current distribution at different frequencies. Their combined use achieves the cooperative control of the current in the entire ultra-wide frequency band, so that the current flows more concentratedly along the desired path, suppresses edge scattering, and improves radiation efficiency.

[0042] As Figure 3 and Figure 5 shown, the application discloses further technical solutions for the main radiation patch 201, and the circular groove 6, the rectangular circular arc groove 8, and the rectangular groove 9 are filled with a dielectric material 10 with a dielectric constant higher than that of the insulating dielectric substrate 1. Preferably, the dielectric material 10 adopts ceramic powder epoxy resin. Filling high dielectric constant materials (such as ceramic powder epoxy resin) in the groove further reduces the wave speed on the already extended current path, realizes deep miniaturization, which is equivalent to electrically compressing the space, allowing the antenna to resonate at a lower frequency, while the physical size remains almost unchanged. The equivalent capacitance in this area can be significantly increased, thereby further reducing the resonant frequency of the antenna.

[0043] As Figure 1 , Figure 3 and Figure 4 shown, the application discloses further technical solutions for the strip-shaped patch 203, and a plurality of wings 11 are connected to the strip-shaped patch 203. The wing 11 is configured as an L-shaped, having a horizontal connection part coplanar with the strip-shaped patch 203 and a vertical radiation part perpendicular to the surface of the insulating dielectric substrate 1. Preferably, the wing 11 adopts a cylinder, and is made into an L-shaped metal sheet by a stamping and bending process, and is then connected to the strip-shaped patch 203 by SMT or welding. The L-shaped wing 11 introduces a vertically polarized radiation component, which, combined with the horizontally polarized wave of the main radiation patch 201, can effectively improve the polarization diversity of the antenna. This structure expands the antenna from a two-dimensional plane to a three-dimensional space. The vertical part acts as a monopole antenna, which is excited by the edge field of the main radiation field to produce radiation with different phase and polarization characteristics. This makes the antenna insensitive to the orientation of underground pipelines. Whether the pipeline is horizontal or vertical, a strong and stable echo signal can be obtained, improving the reliability and efficiency of detection.

[0044] As Figure 6As shown in the figure, the further technical scheme of the application for the insulating medium substrate 1 is disclosed, the mounting flange 12 is arranged on the insulating medium substrate 1 and at the radiation opening end of the exponential tapered slot line, the sleeve 13 is arranged on the mounting flange 12, the inner tube 14 is closely and slidingly arranged in the sleeve 13, the mounting flange 12, the sleeve 13 and the inner tube 14 form an adjustable waveguide port extension structure, the equivalent length of the waveguide port is changed by sliding the inner tube 14, the coupling state of the antenna and the ground (soil) can be dynamically adjusted, when facing the soil with different dielectric constants (such as dry sand and wet clay), the mismatch can be compensated by adjusting, so that the antenna always works in the best state, thereby optimizing the detection depth and signal clarity under different geological conditions.

[0045] As shown in the figure, Figure 1 , Figure 2 and Figure 6 The further technical scheme of the application for the insulating medium substrate 1 is disclosed, and further includes a protective shell 15, the insulating medium substrate 1 is suspended in the protective shell 15 by the elastic damping glue 16, the wing 11 and the mounting flange 12 all penetrate the protective shell 15, the radio frequency connector 17 is arranged on the protective shell 15, the internal contact of the radio frequency connector 17 is connected with the starting end of the microstrip line 402, the radio frequency connector 17 adopts a waterproof SMA or N type connector, the elastic damping glue 16 adopts a silicone or polyurethane potting glue, by arranging the protective shell 15, the insulating medium substrate 1 is suspended in the protective shell 15 by the elastic damping glue 16, thereby playing a protective role for the antenna, ensuring the long-term stability and life of the antenna in the harsh environment in the field.

[0046] The above is the embodiment of the embodiment; but the embodiment is not limited to the above optional embodiment; those skilled in the art can obtain other various embodiments by arbitrarily combining the above modes; anyone can obtain other various forms of embodiments under the inspiration of the embodiment. The above specific embodiments should not be understood as limiting the protection scope of the embodiment; the protection scope of the embodiment should be defined by the claims.

Claims

1. A small ultra-wideband radio frequency antenna for PE pipe detection, characterized by, The application relates to a radiation structure, which comprises an insulating medium substrate (1) and a radiation structure (2) arranged on the front surface of the insulating medium substrate (1), wherein the radiation structure (2) comprises a main radiation patch (201) composed of an exponentially-varying slot line, a ring-shaped patch (202) arranged at the end of the main radiation patch (201), and a strip-shaped patch (203) arranged at the end of the ring-shaped patch (202). The resistance element (3) comprises a first resistance (301), a second resistance (302) and a third resistance (303), the main radiation patch (201) is connected with the ring-shaped patch (202) through the first resistance (301), the two ends of the ring-shaped patch (202) are connected through the second resistance (302), so that the ring-shaped patch (202) forms a closed loop structure loaded with resistance, and the ring-shaped patch (202) is connected with the strip-shaped patch (203) through the third resistance (303). The slot line feeding structure (4) is arranged on the insulating medium substrate (1) and overlaps the starting end of the exponentially-varying slot line in space, and feeds energy to the main radiation patch (201) through electromagnetic coupling. The exponentially-varying slot line of the main radiation patch (201) is etched with a plurality of circular grooves (6) arranged periodically on both sides of the edge. The exponentially-varying slot line of the main radiation patch (201) is etched with a sawtooth-shaped meander structure (7) on both sides of the end. The exponentially-varying slot line of the main radiation patch (201) is etched with a group of rectangular arc grooves (8) and a group of rectangular grooves (9) on both sides respectively.

2. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 1, characterized in that, The slot line feeding structure (4) comprises a circular short-circuit resonant cavity (401) arranged at the starting end of the exponentially-varying slot line, a microstrip line (402) arranged on the back surface of the insulating medium substrate (1), and a fan-shaped open-circuit stub (403) formed at the end of the microstrip line (402), wherein the circular short-circuit resonant cavity (401) and the fan-shaped open-circuit stub (403) are arranged oppositely in space.

3. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 1, characterized in that, Half-elliptical matching grooves (5) are etched on both sides of the main radiation patch (201) and located on both sides of the circular short-circuit resonant cavity (401).

4. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 1, characterized in that, The circular grooves (6), the rectangular arc grooves (8) and the rectangular grooves (9) are filled with a dielectric material (10) with a higher dielectric constant than the insulating medium substrate (1).

5. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 2, characterized in that, A plurality of wings (11) are connected to the strip-shaped patch (203), the wings (11) are configured as L-shaped, and have a horizontal connecting part coplanar with the strip-shaped patch (203) and a vertical radiation part perpendicular to the surface of the insulating medium substrate (1).

6. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 5, characterized in that, An installation flange (12) is arranged on the insulating medium substrate (1) and located at the radiation opening end of the exponentially-varying slot line, a sleeve (13) is arranged on the installation flange (12), and an inner tube (14) is closely and slidingly inserted into the sleeve (13).

7. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 6, characterized in that, The application further comprises a protective shell (15), the insulating medium substrate (1) is suspended in the protective shell (15) through elastic damping glue (16), the wings (11) and the installation flange (12) penetrate through the protective shell (15), a radio frequency connector (17) is arranged on the protective shell (15), and the internal contact of the radio frequency connector (17) is connected with the starting end of the microstrip line (402).

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