JP4558985B2 - Array antenna for concrete structure inspection - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an array antenna for concrete structure inspection.
[0002]
[Prior art]
In concrete structures, such as tunnels and expressways, where severe conditions are imposed, it is necessary to inspect the inside of the structure to maintain safety. As a non-destructive inspection method using a measuring instrument, a single element antenna is used. Measurement was mainly based on the radio waves used.
[0003]
[Problems to be solved by the invention]
While the inspection using the single element antenna is effectively a one-dimensional inspection, a method for two-dimensional inspection using a high frequency radar of several gigahertz has been developed. The antenna used in this case is a two-dimensional inspection of the surface of the structure by placing the array antenna with the antenna elements arranged side by side close to the surface of the structure to be inspected and moving the array antenna in the horizontal direction. Therefore, the inspection efficiency can be improved.
[0004]
By the way, as described above, the array antenna for high-frequency radar needs to arrange each antenna element close to the surface of the structure. Therefore, in the case of a structure whose surface is mainly curved like a tunnel, While an array antenna with a single antenna element attached to the shape is required, the curved surface shape of the tunnel is made of curved surfaces with various curvatures, so many array antennas can be used to accommodate a large number of tunnels. It is necessary to prepare. Therefore, it is necessary to prepare a large number of expensive antenna elements, and there is a problem that the inspection cost increases.
[0005]
The present invention has been made paying attention to the above problem, and the high-frequency antenna elements for inspecting the inside of a concrete structure having a large number of curved surfaces such as tunnels can be easily rearranged along the curved surfaces. An object of the present invention is to provide an array antenna.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an array antenna for concrete structure inspection according to the present invention has a plurality of high frequency antenna elements arranged side by side along the surface shape of the concrete structure to be inspected, and the reflected waves of the radiated high frequency radio waves are reflected. An array antenna that receives and inspects the inside of the structure, the array antenna including an antenna element, a unit antenna to which the antenna element is attached, a connecting member, and an array antenna mounting base, wherein the connecting member is the unit antenna A plurality of antennas are detachably mounted side by side and along the surface of the structure, and fixed to the array antenna mounting base.
[0007]
There is no particular limitation on the means for arranging the unit antennas side by side along the surface shape of the concrete structure to be inspected and attaching them to the connecting member. For example, when the unit antenna is screwed to the connecting member, the antenna elements can be arranged along the surface of the structure to be inspected. Therefore, the edge shape on the side where the connecting member faces the concrete structure surface is formed to have a curvature along the surface shape, and the unit antenna can be fixed along the edge portion. The mounting member can be usually made by processing a metal plate, but the present invention is not limited to this. However, a conductor is desirable.
[0008]
In the present invention, the value of the curvature is not particularly critical, and the curvature is zero, that is, includes a straight line.
[0009]
There is no particular limitation on the means for detachably attaching the unit antenna to the connecting member. For example, it is possible to use a mounting means for providing a screw hole having a common specification at a predetermined position of each of the connecting member and the unit antenna and screwing it.
[0010]
The present invention prepares a number of connecting members suitable for each curved surface (including straight lines) of a concrete structure such as a tunnel to be inspected in advance, so that a smaller number of unit antennas can be maintained while maintaining high measurement accuracy. By preparing, it is possible to inspect a large number of concrete structures to be inspected.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment with reference to the accompanying drawings will be described to specifically describe the present invention.
[0012]
The antenna element 2 used in the present embodiment is composed of a pair of conductors (triangles in the present embodiment) having the same shape as shown in FIG.
[0013]
The feed line 4 attached to each piece of the antenna element 2 is drawn into the casing 3 from the opening 5 opened in the casing 3, and is sent / received by a transmitter / receiver (not shown) via the matching circuit 6. It is connected to a coaxial cable 7 connected to a terminal (not shown).
[0014]
The matching circuit 6 is a circuit that is conventionally used to convert the transmission state from unbalanced (inside coaxial cable line) to balanced (antenna). As means for connecting the antenna element 2 and the coaxial cable 7 including the matching circuit 6, those normally used in this kind of technology can be used as appropriate, and detailed description thereof will be omitted.
[0015]
The casing 3 is for fixing the antenna element 2 to a connecting member 8 (FIGS. 2 to 5) described below, and the shape of the casing 3 used in the present embodiment is a surface on which the antenna element 2 is attached. However, it was a rectangular column with a side of about 57 mm and a height of about 78 mm. However, these shapes and dimensions are examples, and the present invention is not limited to these, and can be appropriately modified in accordance with the use situation. Reference numeral 9 shown in FIG. 1 is a screw hole for screwing the casing 3 to the connecting member 8.
[0016]
The connection member 8 used in the array antenna 10 of the first embodiment shown in FIGS. 2 to 4 is applied to the inspection of a concrete structure (not shown) having a zero curvature, that is, a flat surface.
[0017]
The connecting member 8 of the first embodiment is manufactured by processing a metal plate. As shown in FIG. 3, the connecting member 8a (FIG. 3a) to which the unit antenna 1 having the same specifications is attached. ) And a receiving connecting member 8b (FIG. 3b) (when these are collectively referred to simply as connecting member 8), the unit antenna 1 is attached to each connecting member 8a, 8b with a screw 11 (FIG. 5) ( 16 in the first embodiment), so that the unit antennas 1 of the transmitting connecting member 8a and the receiving connecting member 8b are arranged in a staggered manner (FIG. 2). (Not shown).
[0018]
The array antenna 10 can be used directly on the array antenna mount (or other member so that the antenna element 2 can be moved toward the surface of the concrete structure to be inspected while maintaining a certain distance (for example, 5 mm). A car (not shown) is attached, the array antenna is moved in a direction crossing the longitudinal direction while pressing, the radio wave is radiated and the reflected wave is received repeatedly, and the state in the concrete structure (crack, jumper, Analysis of the defect portion, separation, lifting of the restraint mortar, etc.) and displaying the image on the display, etc., and conventionally used means can be applied to these operations.
[0019]
FIG. 5 shows a transmission connecting member 8a for an array antenna (not shown) of the second embodiment which is used for inspection of a tunnel having a curved surface having a radius of 4791 mm (curvature: 0.02087 m ⁻¹ ). 5a) and a receiving connecting member 8b (FIG. 5b). Coupling member 8 of the second embodiment, the edge 12 facing the examination Target surface is disposed surfaces of the antenna elements (not shown) is formed so as to draw an arc, 16 the number of attachable antenna elements Since it was the same as that of 1st Embodiment except having been made, it attaches the same code | symbol to the same member, and abbreviate | omits description.
[0020]
As described above, the array antenna 10 according to the first and second embodiments is a connecting member having a curvature suitable for the surface shape of the concrete structure to be measured if a necessary number of common antenna elements are manufactured. Since the inspection becomes possible by preparing the inspection cost, the inspection cost can be greatly reduced.
[0021]
【The invention's effect】
As described above, the concrete structure inspection array antenna of the present invention has a shape that matches the surface shape of the inspection target so that the antenna element can be arranged along the surface shape of the inspection target, and the antenna element is detachable. As a result, the total number of expensive antenna elements can be reduced as much as possible, and the inspection cost can be greatly reduced while maintaining high inspection accuracy.
[Brief description of the drawings]
FIG. 1 is a perspective view for explaining an outline of a unit antenna used in an embodiment of the present invention.
FIG. 2 is a perspective view showing a partially omitted array according to the first embodiment of the present invention.
FIG. 3 is a view taken along the line III-III in FIG. 3;
4A is a side view taken along the line IVa-IVa in FIG. 3, and FIG. 4a is a side view taken along the line IVb-IVb in FIG. 3;
5A and 5B are side views of a connecting member according to a second embodiment of the present invention, in which FIG. 5a is a transmission pre-side connection plate, FIG. 5b is a reception side connection plate viewed from the same direction as FIG. FIG.
[Explanation of symbols]
1 Unit antenna 2 Antenna element 7 Coaxial cable (feeding line)
8 Connecting member 10 Array antenna

Claims (2)

An array antenna that arranges a plurality of high-frequency antenna elements side by side along the surface shape of the concrete structure to be inspected, receives the reflected waves of the radiated high-frequency radio waves, and inspects the inside of the concrete structure,
The array antenna is composed of an antenna element, a plurality of unit antennas of the same specification to which the antenna element is attached, a connecting member, and an array antenna mount.
The plurality of unit antennas having the same specifications can be attached to and detached from the connecting member in order to change the orientation of the mounting surface of the antenna elements of the plurality of unit antennas having the same specifications along the surface of the concrete structure. attach the horizontal line in,
An array antenna for concrete structure inspection in which the connecting member is fixed to the antenna mount. A plurality of connecting members having different shapes are prepared as the connecting member, and the plurality of unit antennas having the same specification are selected by using a connecting member that matches the surface shape of the concrete structure from the plurality of connecting members. The array antenna for concrete structure inspection according to claim 1 , wherein the orientation of the mounting surface of the antenna element is changed .

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