Ultra-wideband miniature radio frequency antenna for PE pipe detection

Abstract

The invention discloses an ultra-wideband small radio frequency antenna for PE pipe detection, and relates to the technical field of antennas. The antenna comprises an insulating medium substrate and a radiation structure arranged on the front surface of the insulating medium substrate. The radiation structure comprises a main radiation patch formed by an index gradual change slot line, an annular patch arranged at an interval with the tail end of the main radiation patch, and a strip-shaped patch arranged at an interval with the annular patch. The resistor element comprises a first resistor, a second resistor and a third resistor, and the main radiation patch is connected with the annular patch through the first resistor; a radiation part of the antenna forms a specific resistance loading network through a radiation structure and a resistance element, and a slot line feed structure feeds energy, so that resonance with lower frequency can be effectively excited, and the low-frequency cut-off frequency of the antenna is reduced, which is crucial for detecting a deep target; therefore, the input impedance of the antenna is very stable in the whole ultra-wideband, the energy transmission efficiency is ensured, and the gain and efficiency of the antenna 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 distributed in multiple layers. Among them, PE pipes have become widely used 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. However, in the early urban construction, the laying of PE pipes often leads to difficulties in accurately determining the buried position due to incomplete data records, missing drawings or non-standard management. This brings significant difficulties to subsequent engineering planning, construction and maintenance. To achieve accurate identification of the buried depth and position of underground PE pipelines, it is urgent to develop an efficient and reliable non-destructive testing technology. Ground penetrating radar (GPR) is one of the mainstream detection technologies, and its performance largely depends on the design of the 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 deeper than 2 meters, the resolution and positioning accuracy significantly decrease. In addition, such antennas usually have poor portability and high cost, limiting their widespread application in practical engineering. Therefore, developing a new type of antenna with wide bandwidth, high performance, small size and controllable cost is of great engineering significance and practical value for improving 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. However, for some deeply buried pipelines, it is difficult to detect the specific position. Therefore, in order to achieve deeper detection distance and miniaturization of the detection antenna, there is an urgent need for a solution 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 this problem. SUMMARY

[0003] 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.

[0004] In order to achieve the above-mentioned purpose, the radio frequency antenna disclosed in the present application can adopt the following scheme: The utility model provides a kind of UWB small radio frequency antenna 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 formed by exponential slot line, annular patch is arranged at the end of main radiation patch interval, and strip patch is arranged at the interval of annular patch. 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; Slot line feed structure is arranged on insulating medium substrate, which overlaps the starting end of exponential slot line in spatial position, and feeds energy to main radiation patch by electromagnetic coupling mode.

[0005] Further, the slot line feed structure includes a circular short-circuit resonant cavity arranged at the starting end of the exponential slot line, and a microstrip line is arranged on the back surface of the insulating medium substrate, and a fan-shaped open-circuit stub is configured at the end of the microstrip line.

[0006] Further, a semi-elliptical matching groove is etched on both sides of the main radiation patch and located on both sides of the circular short-circuit resonant cavity.

[0007] Further, a plurality of periodically arranged circular grooves are etched on both sides of the exponential slot line of the main radiation patch.

[0008] Further, a sawtooth meander structure is etched at the end of the exponential slot line of the main radiation patch.

[0009] Further, a group of rectangular circular arc grooves and a group of rectangular grooves are etched on both sides of the exponential slot line of the main radiation patch.

[0010] Further, the circular grooves, the rectangular circular arc grooves, and the rectangular grooves are filled with a dielectric material having a higher dielectric constant than the insulating medium substrate.

[0011] Further, a plurality of wings are connected to the strip patch, the wings are configured as L-shaped, having a horizontal connection part coplanar with the strip patch and a vertical radiation part perpendicular to the surface of the insulating medium substrate.

[0012] Further, a mounting flange is arranged on the insulating medium substrate and located at the radiation opening end of the exponential slot line, a sleeve is arranged on the mounting flange, and an inner tube is tightly and slidably inserted into the sleeve.

[0013] Further, a protective shell is further included, the insulating medium substrate is suspended in the protective shell by elastic damping glue, the wing and the mounting flange are both penetrated through the protective shell, and a radio frequency connector is arranged on the protective shell, and the internal contact of the radio frequency connector is connected with the starting end of the microstrip line.

[0014] Compared with the prior art, part of the beneficial effects of the technical scheme of the present application includes: 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, the slot line feeding structure feeds energy, which can effectively excite lower frequency resonance, reduce 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 throughout the ultra-wide frequency band, ensuring energy transmission efficiency, and the antenna gain and efficiency are gradually increased.

[0015] 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 annular patch for radiation, the second resistance is connected at the head and tail of the annular patch to reduce the influence of current backflow, and the third resistance radiates the excess energy in the annular patch again to reduce the reflection at the low frequency end and improve the low frequency characteristics.

[0016] 3、In the present application, two different rectangular slots are etched in the main radiation part, by etching short and narrow rectangular slots and wide and long rectangular arc slots, the backflow strength of the edge of the main radiation patch is weakened, the current strength near the exponential line of the patch is enhanced, and the three triangular etchings at the end of the antenna work together to effectively extend the effective path of the current. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below, and 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, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0018] Figure 1 is a perspective view of the present application.

[0019] Figure 2 is a perspective view of the present application.

[0020] Figure 3 is a perspective view of part of the structure of the present application.

[0021] Figure 4 is a perspective view of part of the structure of the present application.

[0022] Figure 5 This is a partial planar front view of the structure of this invention.

[0023] Figure 6 This is the present invention. Figure 2 Enlarged view of point A in the middle.

[0024] 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

[0025] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this embodiment.

[0026] 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.

[0027] Example 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. 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 pad for welding resistance and the connection trace 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 way of soldering on the copper foil pad which is designed in advance in the etching stage, so that a specific resistance loading network is formed; The slot line feeding structure 4 is arranged on the insulating medium substrate 1, 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 become a closed loop for energy consumption, further consumes energy, and the third resistance 303 couples the final energy to the strip patch 203 for the last radiation, which can effectively reduce the end reflection of the antenna, reduce the current flowing back to the feeding point, improve the low-frequency impedance matching, at the same time, can extremely effectively widen the low-frequency bandwidth, especially 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 mismatching at the end of the structure, so that the input impedance of the antenna is very stable in the entire ultra-wide frequency band, ensures the energy transmission efficiency, and the antenna gain and efficiency are gradually increased; In the scheme, the radiation part of the antenna forms a specific resistance loading network through the radiation structure 2 and the resistance element 3, the slot line feeding structure 4 feeds energy, which can effectively excite resonance at a lower frequency, 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, ensures the energy transmission efficiency, and the antenna gain and efficiency are gradually increased.

[0028] As Figure 3 and Figure 4The specific structure of the slot line feeding structure 4 of the present invention is disclosed. The slot line feeding structure 4 includes a circular short-circuit resonant cavity 401 disposed at the starting end of the exponentially gradient slot line. A microstrip line 402 is disposed on the back side of the insulating dielectric substrate 1. The end of the microstrip line 402 is constructed with a fan-shaped open-circuit stub 403. The circular short-circuit resonant cavity 401 and the fan-shaped open-circuit stub 403 are spatially opposite to each other. A thin layer of electrolytic copper foil is covered on the back side of the insulating dielectric substrate 1. The microstrip line 402 and the fan-shaped open-circuit stub 403 are formed by photolithography etching. The circular short-circuit resonant cavity 401 is usually formed by metallized vias (first drilling, then electroplating the vias). (By metallizing the wall) to achieve a short circuit, the radio frequency signal is introduced from the starting end of the microstrip line 402. The signal propagates along the microstrip line 402 to the fan-shaped open stub 403 at the end. Through electromagnetic field coupling, the energy passes through the insulating dielectric substrate 1 and excites the slot line mode at the circular short-circuited resonant cavity 401 on the front side, completing the conversion from an unbalanced transmission line to a balanced transmission line. Through the coordinated design of the circular short-circuited resonant cavity 401 (front side) and the fan-shaped open stub 403 (back side), efficient coupling and mode conversion from the unbalanced microstrip line 402 to the balanced slot line are achieved, while providing good impedance matching to ensure that the antenna can work stably in the ultra-wideband frequency band.

[0029] like Figure 3 and Figure 5 As shown, the present invention discloses a further technical solution for the main radiating patch 201. Semi-elliptical matching grooves 5 are etched on both sides of the main radiating patch 201 and located in the circular short-circuit resonant cavity 401. By etching the semi-elliptical matching grooves 5, they can be used as fine-tuning knobs to make local fine adjustments to the electromagnetic field of the most critical area of ​​the feed point, thereby achieving in-depth optimization of the standing wave ratio and ensuring unobstructed energy entry.

[0030] like Figure 3 and Figure 5 As shown, a further technical solution for the main radiating patch 201 of the present invention is disclosed. Multiple periodically arranged circular grooves 6 are etched on both sides of the exponentially gradient groove line of the main radiating patch 201. By etching the periodically arranged circular grooves 6, the current slows down when flowing through these periodic structures, generating a significant slow wave effect, reducing the phase velocity, which is equivalent to increasing the electrical length, and realizing resonance at a lower frequency without changing the physical size, i.e., miniaturization.

[0031] like Figure 5 As shown, a further technical solution for the main radiating patch 201 of the present invention is disclosed. Sawtooth meandering structures 7 are etched at both ends of the exponentially gradient groove line of the main radiating patch 201. By etching sawtooth meandering structures 7, a bent current path is physically formed, which directly increases the distance through which the current flows, further extends the electrical length and reduces the resonant frequency, thereby improving practicality.

[0032] 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 the two 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 the protective shell 15 is further included, 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 both 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 the waterproof SMA or N type connector, the elastic damping glue 16 adopts the 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.

[0037] The above is the embodiment of the embodiment; but the embodiment is not limited to the above optional embodiment; the person 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 the spatial position, and feeds energy to the main radiation patch (201) through electromagnetic coupling.

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, the back surface of the insulating medium substrate (1) is provided with a microstrip line (402), the end of the microstrip line (402) is provided with a fan-shaped open-circuit branch (403), and the circular short-circuit resonant cavity (401) and the fan-shaped open-circuit branch (403) are oppositely arranged in the 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 the main radiation patch (201) and located on the two 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, A plurality of circular grooves (6) arranged periodically are etched on the two side edges of the exponentially-varying slot line of the main radiation patch (201).

5. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 1, characterized in that, Sawtooth-shaped meander structures (7) are etched on the two side ends of the exponentially-varying slot line of the main radiation patch (201).

6. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 4, characterized in that, A group of rectangular circular-arc grooves (8) and a group of rectangular grooves (9) are respectively etched on the two sides of the exponentially-varying slot line of the main radiation patch (201).

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

8. 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 in an L shape 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).

9. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 8, 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 arranged in the sleeve (13).

10. The ultra-wideband small radio frequency antenna for PE pipe exploration according to claim 9, characterized in that, Further, a protective shell (15) is arranged, 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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