CN110994161B - Asymmetric broadband dipole antenna for borehole radar - Google Patents

Abstract

The invention discloses an asymmetric broadband dipole antenna for drilling radar, which comprises a base plate and a hollow metal tube arm. One end of the metal tube arm is provided with a tapered body, and its interior is divided by a partition in the length direction. The upper cavity and the lower cavity are formed; the end of the cone located on the side of the upper cavity is the open end, and the end located on the side of the lower cavity is the closed end, and the end of the baffle located on the side of the cone is connected with the end sidewall of the cone; The upper surface is etched with interconnected microstrip lines and microstrip arms, and the substrate etched with the microstrip line side is placed on the separator, the microstrip line constitutes the upper conductor of the impedance transformer, and the separator constitutes the lower part of the impedance transformer. Conductor; a wire hole is opened on the side wall of the non-tapered body end of the metal tube arm.

Description

Asymmetric broadband dipole antenna for borehole radar

technical field

The present invention relates to radar systems, in particular to an asymmetric wideband dipole antenna for borehole radar.

Background technique

In view of the working system and working environment of the borehole radar system, there are high requirements on the antenna bandwidth and size. At present, the mainstream borehole radar system antenna is mainly based on the traveling wave dipole loaded by resistance. This dipole can meet the bandwidth and size requirements of the system, but the radiation efficiency is relatively low, which weakens the detection ability of the radar system.

SUMMARY OF THE INVENTION

In view of the above deficiencies in the prior art, the asymmetric broadband dipole antenna for borehole radar provided by the present invention solves the problem of low radiation efficiency of the existing dipole antenna.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

Provided is an asymmetric broadband dipole antenna for borehole radar, which includes a base plate and a hollow metal tube arm, one end of the metal tube arm is provided with a conical body, and its interior is divided into an upper cavity by a lengthwise partition body and lower cavity; the end of the conical body located on the side of the upper cavity is the open end, and the end located on the side of the lower cavity is the closed end, and the end of the baffle located on the side of the conical body is connected to the end sidewall of the conical body;

The upper surface of the substrate is etched with interconnected microstrip lines and microstrip arms, the substrate etched with the microstrip line side is placed on the separator, the microstrip line constitutes the upper conductor of the impedance transformer, and the separator constitutes the upper conductor of the impedance transformer. The lower conductor; the side wall of the non-tapered body end of the metal tube arm is provided with a wire hole.

The beneficial effects of the present invention are: one arm of the dipole antenna of this solution is composed of a microstrip arm, and the other arm is a hollow metal tube arm. This design can improve the radiation efficiency of the antenna while ensuring the antenna bandwidth.

In addition, the hollow metal tube arm can accommodate the main components of the radar system. When some components of the radar system are installed in the metal tube arm, the external electromagnetic interference can be shielded by the metal tube arm, and the size of the system can also be greatly reduced; The impedance transformer is installed in the metal tube arm to achieve good impedance matching without increasing the volume of the dipole antenna.

Description of drawings

FIG. 1 is a cross-sectional view of an asymmetric broadband dipole antenna for borehole radar along a direction perpendicular to a substrate.

FIG. 2 is an enlarged view of part A in FIG. 1 .

3 is a cross-sectional view of an asymmetric broadband dipole antenna for borehole radar along a direction parallel to the substrate.

FIG. 4 is an enlarged plan view of FIG. 3 .

Figure 5 is a comparison diagram of the antenna return loss under the condition of different groups of patches when the loading resistance is not set.

FIG. 6 is a comparison diagram of the return loss of the antenna when the impedance transformer is added and the impedance transformer is not added.

Among them, 1. metal pipe arm; 11, wire hole; 12, partition plate; 13, cone; 14, upper cavity; 15, lower cavity; 151, lower cabin; 152, plate body; 153, pass through Hole; 2. Impedance converter; 3. Substrate; 31, Microstrip line; 32, Microstrip arm; 321, SMD; 33, Loading resistor;

Detailed ways

The specific embodiments of the present invention are described below to facilitate those skilled in the art to understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Such changes are obvious within the spirit and scope of the present invention as defined and determined by the appended claims, and all inventions and creations utilizing the inventive concept are within the scope of protection.

As shown in Figure 1, Figure 3 and Figure 4, the asymmetric broadband dipole antenna for borehole radar includes a substrate 3 and a hollow metal tube arm 1, wherein the metal tube arm 1 is made of low-density metal material , such as metal aluminum; the thickness of the substrate 3 is at least 2 mm, so that the substrate 3 has a certain strength.

As shown in FIG. 2 , one end of the metal tube arm 1 is provided with a tapered body 13 ; the inside of the metal tube arm 1 is divided into an upper cavity 14 and a lower cavity 15 by a partition 12 in the longitudinal direction. The end of the conical body 13 on the side of the upper cavity 14 is the open end, and the end on the side of the lower cavity 15 is the closed end.

The beginning of the end of the cone 13 is actually not provided with a side wall, and the closed end of the end of the cone 13 is actually a structure with a side wall. The upper conductor of the impedance transformer composed of the partition plate 12 is connected to the microstrip arm 32 , and the lower conductor is connected to the metal tube arm 1 . Then, the radar source feeds the antenna through the impedance converter.

As shown in FIG. 3 , the microstrip line 31 and the microstrip arm 32 connected to each other are etched on the upper surface of the substrate 3 , the substrate 3 etched on the side of the microstrip line 31 is placed on the separator 12 , and the microstrip line 31 constitutes an impedance The upper conductor of the transformer 2 and the partition plate 12 constitute the lower conductor of the impedance transformer 2; the side wall of the non-tapered body 13 of the metal tube arm 1 is provided with a wire hole 11.

The microstrip line 31 is arranged on the substrate 3 in a square wave shape, and the impedance converter 2 formed by the microstrip line 31 and the spacer 12 is used to realize impedance matching between the radar signal source and the antenna. Feed power at the feeding point of the impedance transformer 2, and connect to the two arms of the dipole antenna - the metal tube arm 1 and the microstrip arm 32 through the impedance transformer 2, to realize the connection between the dipole antenna and the system signal source. match.

Referring again to FIG. 1 , the lower cavity 15 is divided into a plurality of lower cabins 151 by a height direction plate 152 , and through holes 153 are formed in the plate 152 located between two adjacent lower cabins 151 . The wiring hole 11 and the through hole 153 are mainly used for wiring.

After the lower cavity 15 is divided into a plurality of lower cabins 151 by the plate body 152, the components of the radar system can be placed in each lower cabin 151 independently, so as to avoid electromagnetic mutual interference when the devices are working. In addition, the plate body 152 can support the partition plate 12 in addition to reducing the interference between the devices, thereby improving the stability of the partition plate 12 .

After the metal tube arm 1 of the dipole antenna is designed with the above structure, it mainly has two functions: first, it is used as an arm of the dipole antenna, and second, there are four cabins inside the metal tube arm 1 ( Three lower cabins 151 plus an upper cavity 14) are used to install other components of the borehole radar and shield external electromagnetic interference to ensure the normal operation of the system, and this design can also greatly reduce the size of the system.

In one embodiment of the present invention, the microstrip arm 32 includes a plurality of groups of patches 321 with different lengths, and all the patches 321 adjacent to the ends of the microstrip line 31 are converged and connected to the microstrip line 31; each patch 321 is connected to the microstrip line 31. The lengths of the patches 321 on both sides are not equal, and the two adjacent patches 321 are connected by a loading resistor 33 .

The patches 321 of different lengths make the antenna have multiple resonance points, and the loading resistors 33 bridged between the patches 321 of different lengths are used to realize the frequency reconstruction of the antenna, which is widened under the premise of ensuring that the size of the antenna meets the requirements of the radar system. Dipole antenna bandwidth, and achieve high-efficiency radiation.

When widening the bandwidth of the antenna, the number of antenna resonant points can be increased by increasing the number of patches 321 with different lengths, but the size of the dipole antenna will increase with the increase in the number of patches 321. For bandwidth requirements, three groups of patches 321 with different lengths can meet the requirements of the radar in the well. Therefore, in this solution, the microstrip arm 32 is preferably composed of three groups of patches 321 with different lengths, so that it has three resonance points.

During implementation, in this solution, the loading resistor 33 is preferably arranged at the end of the adjacent patch 321 .

Figure 5 shows the simulation results of the return loss of the three antennas without the addition of the jumper resistance. 687.5mm and 897.5mm), three groups of patches of different lengths (the patch lengths are 582.5mm, 687.5mm and 897.5mm respectively), and the length of the hollow metal tube is 897.5mm; Figure 6 shows the antenna under the condition of impedance converter And the simulation results of return loss without impedance converter, the antenna microstrip arm consists of three groups of patches with different lengths, the lengths are 897.5mm, 687.5mm, 582.5mm, and the length of the metal tube is 897.5mm. The resistance value of the connecting resistance is 1.5KΩ, and the designed impedance converter is 50-120Ω impedance transformation.

From the return loss coefficient of the dipole antenna in Figure 5, it can be seen that it is not feasible to simply use patches 321 of different lengths to widen the bandwidth of the antenna, because it is difficult to reconstruct the antenna frequency because the resonant points cannot overlap. , so in this scheme, the loading resistor 33 is connected between the patches 321 of different lengths of the microstrip arm 32 , and the antenna frequency reconstruction is realized by using the loading resistor 33 .

It can be seen from Figure 6 that after setting the loading resistor 33, the input impedance of the dipole antenna changes, making it mismatch with the 50 ohm signal source impedance. Therefore, it is necessary to use the impedance converter 2 to realize the impedance matching between the signal source and the antenna. This scheme The "square wave" microstrip line 31 is etched on one end of the substrate 3 and extends into the metal tube arm 1, which not only realizes the impedance transformation between the dipole antenna and the source, but also does not increase the size of the antenna.

In addition, the patch 321 of the present solution is not limited to the arrangement in FIG. 4 , as long as the size of each patch 321 is properly adjusted, the effect that the patch 321 arranged in FIG. 4 can achieve can also be achieved.

When implemented, it is preferred that the asymmetric broadband dipole antenna also includes an insulating watertight tube 4, the substrate 3 and the metal tube arm 1 are installed in the insulating watertight tube 4, and the insulating watertight tube 4 where the wire-passing hole 11 is located is opened. Its matching wire hole 11.

The insulating watertight tube 4 is used to seal the system to ensure that the radar system can be used in an environment where liquid exists, thereby broadening the application scenarios of the dipole antenna.

Claims (6)

1. An asymmetrical broadband dipole antenna for borehole radar, characterized in that it comprises a base plate and a hollow metal tube arm, and one end of the metal tube arm is provided with a tapered body, and its interior passes through a lengthwise baffle plate. It is divided into an upper cavity and a lower cavity; the end of the cone located on the side of the upper cavity is an open end, and the end located on the side of the lower cavity is a closed end, the baffle is located at the end of the side of the cone, and the baffle connected with the end sidewall of the cone; The upper surface of the substrate is etched with interconnected microstrip lines and microstrip arms, the substrate etched with the microstrip line side is placed on the separator, the microstrip line constitutes the upper conductor of the impedance converter, and the separator constitutes The lower conductor of the impedance transformer; the side wall of the non-tapered body end of the metal tube arm is provided with a wire hole; The microstrip arm includes multiple groups of patches with different lengths, and all the patches adjacent to the ends of the microstrip line are gathered together and connected to the microstrip line; the lengths of each patch and the two patches on the adjacent two sides are unequal , the two adjacent patches are connected by loading resistors; the microstrip lines are arranged on the substrate in a square waveform. 2 . The asymmetric broadband dipole antenna for borehole radar according to claim 1 , wherein the loading resistors are arranged at the ends of adjacent patches. 3 . 3 . The asymmetric broadband dipole antenna for borehole radar according to claim 1 , wherein the lower cavity is divided into a plurality of lower cabins by the plate body in the height direction, which are located adjacent to 3 . A through hole is opened on the plate body between the two lower cabin bodies. 4. The asymmetric broadband dipole antenna for borehole radar according to claim 1, characterized in that, further comprising an insulating watertight tube, wherein the base plate and the metal tube arm are installed in the insulating watertight tube, The insulating watertight pipe where the wire-passing hole is located is provided with a wire-passing hole matching the wire-passing hole. 5 . The asymmetric broadband dipole antenna for borehole radar according to claim 1 , wherein the thickness of the substrate is at least 2 mm. 6 . 6 . The asymmetric broadband dipole antenna for borehole radar according to claim 1 , wherein the metal tube arm is made of low-density metal material. 7 .

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