JPS588764B2 - Manufacturing method of slot array antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to manufacturing a slot array antenna that forms a plurality of slots in a waveguide, radiates electromagnetic waves from each slot, and synthesizes them in space to form a beam of a desired shape. Regarding the method.

For example, as shown in FIG. 1, a slot array antenna is constructed by forming an edge on the side wall surface 1a of a rectangular waveguide 1 made by bending a metal plate with a thickness of about 1 mm, and extending between both edges of the rectangular waveguide 1.
edgeshunt slot
2 with a desired inclination angle θ, or
An axial slot (longitudinal shunt slot) is formed on the lower wall surface 1b with a required dimension δ between the waveguide center l1 and the slot center.
nal, hunt, slot) 3).

In this case, the slot 2 is generally formed by cutting with a milling cutter, and the slot 3 is bored by electrical discharge machining or the like, but this is a fairly troublesome operation.

That is, the power radiated from each slot 2, 3 needs to be controlled based on a required function, and even slots of the same type have different inclination angles θ and deviation values δ, so it is difficult to During electrical discharge machining, the angle must be adjusted or aligned each time, which requires a lot of time and effort.

Furthermore, there is a problem with the processing accuracy, especially the uniformity when making large quantities of the same product.

In addition, the width of each slot 2 and 3 has become narrower as the frequency of use increases, for example from about 1.5 mm in the 10 GHz band to about 0.2 to 0.3 mm in the 50 GHz band. I have to do it, but 0, 2-0.
When creating a slot with a very narrow width of about 3 mm using a milling cutter, a special thin blade is required, and when creating a slot using electrical discharge machining, the jig is subject to severe wear and tear, resulting in high precision, high efficiency, and high stability. High-level processing is no longer possible.

Therefore, the upper limit frequency of the antenna is limited by the processing tool.

Therefore, there is a need for a manufacturing method that can stably produce high-precision slot array antennas for ultra-high frequency bands in large quantities.

By the way, recent etching techniques have made it possible to etch relatively thick metal plates, with an accuracy of about 1/10 of the thickness.

In other words, if the thickness is 0.1 to 0.2 mm, 1/1
A pattern accuracy of about 0.00 to 2/100 mm can be obtained.

This level of accuracy is sufficient for an antenna slot.

The present invention utilizes such etching technology to provide a method for manufacturing a slot array antenna that can uniformly mass-produce a large number of high-precision slot array antennas, especially antennas for ultra-high frequency bands. It is something.

A method for manufacturing a slot array antenna according to the present invention includes forming a plurality of slots in a thin metal plate by etching, and after forming the slots, bending the metal plate to form a waveguide, and using this as an antenna. A metal plate with a slot formed therein is bent into a U-shape, and a metal substrate thicker than the metal plate is applied to this and the edges are joined to form a waveguide with a rectangular cross section, and this is used as an antenna. Hereinafter, this will be explained in detail based on the deaf model shown in the drawings.

First, a mask with a predetermined pattern, for example, an edge shunt slot pattern is made, and this mask is used to make a thin plate of easily etched metal such as copper or brass (for example, 0.2 mm thick) as shown in Figure 2a. ) 11 to form a slot 12 by etching.

The slot 12 has a length of approximately λ/2 (double wavelength) and a width of 0.2 to 0.0 GHz for an ultra-high frequency band of several tens of GHz, for example, a 50 GHz band. 3 mm, and several dozen slots are provided with an interval of about 3 mm.

Further, the metal thin plate 11 has a width that can constitute the left and right side walls and the top surface of the rectangular waveguide, and its length is 100 mm.
That's about it.

Therefore, etching can be easily performed from both sides by immersing it in an etching bath.

After the slots have been formed, the thin metal plate is bent, for example, by a press into a U-shape as shown in FIG. 2b.

Each of the surfaces 11a to 11c separated by the bending line becomes a wall surface of a rectangular waveguide, and both side surfaces 11a and 11
The widths of c are equal and the spacing is slightly shorter than half a wavelength.

Therefore, the slot 12 having a length of half a wavelength extends not only to the upper surface 1lb but also to both side surfaces 11a and 11c.

That is, the slot 12 constitutes a so-called bent dipole.

The bottom substrate 13, which is the remaining wall of the rectangular waveguide, is made of the same type of metal plate as the thin metal plate 11, and its thickness is equal to that of the thin metal plate 11.
As shown in FIG. 2C, stepped portions 13a and 13b are provided on both sides of the thin plate 11 on which the side edges of the two supports 11a and 11c of the thin plate 11 are placed.

A bent thin metal plate 1 is placed on this substrate 13 as shown in FIG. 2d.
1 is placed thereon, and while being held with an appropriate jig, the joining portions thereof, that is, the step portions 13a and 13b of the substrate 13 and the side edges of both side surfaces 11a and 11c of the thin plate 11 are line welded together using a plasma welding method.

This integration completes the waveguide, and this waveguide has slots and
Configure the array antenna.

Since the shape of the thin plate 11 is restricted by the relatively thick substrate 13 in the completed state, even if the thin plate 11 is a thin plate 11 that can be etched with high precision, a waveguide with a flat inner wall surface and a predetermined size can be formed. There is no problem with electrical performance.

Further, since the slot 12 is precisely formed by etching, there is no burr that is seen during machining, and high machining accuracy can be obtained.

Moreover, if one pattern is made, it is easy to uniformly form many of the same pattern, and by using a progressive press for the subsequent bending process and fixing the substrate 13 and the thin plate 11 by welding. Mass production is possible.

Note that the slots are not limited to edge, shunt, and flot shapes, and slots of other shapes can be similarly formed with high precision.

As described in detail above, according to the present invention, high-precision slot array antennas can be rapidly manufactured in large quantities by using thin metal plates and etching them.

In addition, since the antenna for the ultra-high frequency band of several tens of GHz can be small, it does not require a special large etching bath or press machine, and the equipment is simple.

Furthermore, since the waveguide is formed from a very thin metal plate, its external dimensions are small, and when used as a primary radiator, there is an advantage that the influence of blocking of the primary radiator is small.

[Brief Description of the Drawings] Fig. 1 is a perspective view showing an example of a conventional slot array antenna, and Fig. 2 a = d is a plan view showing the manufacturing process of the slot array antenna according to the method of the present invention. FIG. 11; thin metal plate, 12; slot, 13; metal substrate, 1
3a, 13b: Stepped portion.

Claims (1)

[Claims] 1. A method for manufacturing a slot array antenna, which comprises forming a plurality of slots on a thin metal plate by etching, and after forming the slots, bending the metal plate to form a waveguide, and using this as an antenna. 2. A patent claim characterized in that a metal plate with a slot formed therein is bent into a U-shape, a metal substrate thicker than the metal plate is applied to the bent edge, and the edges are joined to form a waveguide with a rectangular cross section. A method for manufacturing a slot array antenna according to item 1.