JPS6269702A - Microstrip line - Google Patents

Abstract

PURPOSE:To obtain a microstrip line with less warpage and high gains by forming a resin layer made of polyolefine resin even on a surface at a side opposite to that on which the dielectric layer of a ground conductor layer is formed. CONSTITUTION:First, a crank-like strip conductor 3 is formed on the surface of a resin thin layer 4. Next, the dielectric layer 2, the ground conductor layer 1 and the resin layer 5 are piled in this order on the surface at the side where the strip conductor 3 of the resin thin layer 4 is formed. Third, an adhesive material and an adhesive film are inserted between respective layers, melted, pressurized and applied to obtain the microstrip line. If the resin layer 5 made of the polyolefine resin used also for the dielectric layer 2 is formed at the side opposite to the ground conductor layer 1 in such a way, the resin layer 5 and the dielectric layer 2 installed opposite to the ground conductor layer 1 offset each other their warping force in the melting, pressurizing and applying steps, thereby reducing the warpage. Accordingly high gains can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a microstrip line used in a planar antenna for receiving SHF (microwave) and the like.

[Background technology]

For example, a microstrip line as shown in FIG. 2 is used as an SHF (microwave) receiving antenna. This is a type of microstrip in which a crank-shaped strip conductor 3 is provided on the surface of a metal ground conductor layer 1 via a dielectric layer 2 made of polyolefin resin, and a resin thin film 4 is further formed on the crank-shaped strip conductor 3. It is a line antenna. In such a microstrip line, if the Young's modulus of the polyolefin resin (for example, polyethylene, etc.) used as the dielectric layer 2 is high or the thickness of the metal plate that is the ground conductor layer 1 is thin, melt pressure bonding by hot pressing may occur. During these steps, warping occurs as shown in FIG. 3 due to differences in expansion and contraction rates of each layer. When warping as shown in the figure occurs, the gain decreases when used as an antenna, making it impossible to receive efficiently.

When the inventors investigated the relationship between the warpage and the decrease in antenna gain for the microstrip line antenna shown in the figure, it was observed that the gain decreased by about 0.36 dB for each degree of warpage.

Therefore, in order to prevent such warping, the dielectric layer 2
As a possible solution, it is possible to use a polyolefin resin with a low Young's modulus or to increase the thickness of the metal plate that is the ground conductor layer 1. However, polyolefin resin with a low Young's modulus has high fluidity when melted, so when each layer is laminated and heat-pressed, some of the resin flows, causing variations in the thickness of the completed microstrip line. There is a fear. Furthermore, the method of increasing the thickness of the metal plate is problematic because it increases the weight and costs.

[Purpose of the invention]

The present invention was made in view of the above problems, and an object of the present invention is to provide a microstrip line with less warpage and high gain.

[Disclosure of the invention]

In order to achieve the above object, the present invention provides a microstrip line in which a strip conductor is provided on the surface of a ground conductor layer through a dielectric layer made of polyolefin resin, wherein the dielectric layer of the ground conductor layer is The gist of the microstrip line is that a resin layer made of polyolefin resin is also formed on the surface opposite to the side on which it was formed.

Hereinafter, one embodiment of the present invention will be explained in detail based on FIG. 1. This embodiment shows the case where the present invention is used in a microstrip line antenna.

As the ground conductor layer 1, an aluminum plate or the like that is usually used for microstrip lines can be used. The thickness does not need to be as thick as described above, and may be a normal thickness (for example, 1.Q mm, 0.5 ms, etc.).

The dielectric layer 2 is made of a polyolefin resin such as low-density polyethylene, high-density polyethylene, or a blend thereof by extrusion molding, and has a thickness of 0.5 mm.
A sheet-like material having a diameter of 8 to 1.2 mm is used.

As the strip conductor 3, for example, aluminum foil,
Metal foil such as copper foil is used. Such a strip conductor 3 is formed, for example, as follows. That is, first, a metal foil is bonded to the resin thin film 4 formed to protect the surface of the strip conductor 3 or to the surface of the dielectric layer 2 by dry laminating or the like. Next, this metal foil is etched to form the strip conductor 3 in a predetermined shape.

In the illustrated embodiment, the strip conductor 3 has a continuous crank shape in order to improve the directivity of the antenna, but the shape is not limited to this. In short, as long as the pinch in the length direction corresponds to the wavelength of the received radio waves, it may be in a meandering shape or a zigzag shape. As mentioned above, the resin thin film 4 is attached to the strip conductor 3.
Although it is used to protect the surface and is not necessarily required for this invention, if the resin thin film 4 is provided as in the embodiment shown in the figure, it will prevent the strip conductor 3 from being corroded or damaged. It can be prevented. Examples of such a resin thin film 4 include a film-like material made of polyester, polypropylene, or the like.

The above layers are laminated as shown in Figure 1, and a resin layer 5 is further formed on the surface of the ground conductor layer l opposite to the side on which the dielectric layer 2 is formed. The invention consists of: Although the method for creating the microstrip line of the present invention is not particularly limited, for example, the following method can be used. First, resin thin film 4
A crank-shaped strip conductor 3 is formed on the surface by the method described above. Next, a dielectric layer 2, a ground conductor layer 1.
The resin layers 5 are stacked in this order.

Adhesive or adhesive film is placed between each layer.

The microstrip line of the present invention can be obtained by melting and press-bonding this material using a hot press, a hot roll, or the like.

In this way, if the resin layer 5 made of the same polyolefin resin as the dielectric layer 2 is formed on the opposite side of the ground conductor layer 1, this resin layer 5 can be used even during the melt pressure bonding process using heat press, for example. , and the dielectric layer 2 provided on the opposite side of the ground conductor layer 1 cancel each other's warping forces, thereby reducing warpage.

The thickness of the resin layer 5 is not particularly limited, but in order to function as described above, it should have approximately the same thickness as the dielectric layer 3 (approximately 80 to 120% of the thickness of the dielectric layer). It is preferable to use the remaining ones. For example, if the dielectric layer 3 is a sheet-like material with a thickness of 0.8 to 2 liters as described above, the resin layer 5 is also made of the same polyolefin resin and is a sheet-like material with a thickness of 80-1
If a sheet-like material with a 20% strength is used, the warping force of both materials is almost the same, so the warpage can be reduced. Furthermore, if the dielectric material N3 and the resin layer 5 are superimposed so that their directions (for example, the extrusion direction) are perpendicular to each other, the warping force can be canceled in both directions, so that the warping can be further reduced. Become.

In the above embodiments, only the case where the microstripline line of the present invention is used as a microstrip line antenna has been described, but the application of the present invention is not limited to antennas. It can also be used for so-called line applications for transmitting microwaves and the like. Furthermore, in that case, the strip conductor does not need to be crank-shaped, meandering, or zigzag-shaped as described above, but only needs to be linear.

As described above, the microstrip line of this invention is
A resin layer made of the same polyolefin resin as the dielectric layer is also formed on the surface of the ground conductor layer opposite to the side on which the dielectric layer is formed. Even when this is done, the resin layer and the dielectric layer cancel each other's warping forces, resulting in less warping and higher gain.

Next, examples of the present invention will be described together with comparative examples.

(Examples 1 to 5) A commercially available polyester film (thickness 50 μm) was used as a resin thin film, and a 10 μm thick aluminum film was applied to the surface of the resin film.

Minilam foil was attached using the dry lamination method.

After drawing a pattern to become a strip conductor on the surface of the aluminum foil with photoresist, etching was performed with a ferric chloride solution to form a strip conductor. First, a high-density polyethylene sheet (manufactured by Showa Denko K.K. 2, thickness 1.0) was superimposed as a dielectric layer on the surface of the resin thin film on the side on which the strip conductor was formed. Next, thickness 1
．． 0 aluminum plate (9 alloy number 5 manufactured by Nippon Light Metal Co., Ltd.)
052H34: JIS H4000) was overlaid. Finally, a resin layer made of the same high-density polyethylene sheet as the previous dielectric layer and having the thickness shown in Table 1 was superimposed on the previous dielectric layer so that its directionality was perpendicular to the previous dielectric layer. Note that a polyolefin adhesive film (manufactured by Mitsubishi Yuka Co., Ltd., thickness 100 μm) was sandwiched between each layer as an adhesive layer. This material was heated at 160°C for 3 hours using a heat press.
A microstrip line was created by melt-pressure bonding under conditions of kg/c+a. This microstrip line was cut into a size of 450 x 450 m, placed on a surface plate, the distances between the surface plate and the four corners were measured, and the average value was calculated as the amount of warpage. The results are shown in Table 1. In addition, in the case where the warpage was negative, contrary to the comparative example, the warp was observed to occur in the direction in which the resin layer was placed on the inside.

(Comparative Example 1) Microstrip lines were produced in the same manner as Examples 1 to 5, except that no resin layer was formed, and warpage was measured. The results are also shown in Table 1.

(Examples 6 to 8) As a ground conductor, an aluminum plate with a thickness of 0.5 ** (manufactured by Nippon Light Metal Co., Ltd. 2 alloy number 1070H24: JIS H
4000) was used, microstrip lines were produced in the same manner as in Examples 1 to 5, and warpage was measured.

The results are shown in Table 2.

(Comparative Example 2) Microstrip lines were created in the same manner as Examples 6 to 8, except that no resin layer was formed, and warpage was measured. The results are also shown in Table 2.

*1 The warpage is too large to be measured [Effect of the invention] The microstrip line of this invention is constructed as described above, and there is also a resin layer on the surface opposite to the side on which the dielectric layer is formed. The resin layer and the dielectric layer cancel each other's warping forces, resulting in less warping and, as a result, higher gain.

[Brief Description of the Drawings] Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a perspective view of a conventional example, and Fig. 3 is a sectional view illustrating warping of the conventional example. . l...Ground conductor layer 2...Dielectric layer 3...Strip conductor 5...Resin layer Agent Patent attorney Takeshi Matsumoto Industry 1 Figure 3 Figure 2 Figure 3 Hand 3 Jε Nail IT book ( Spontaneous January 18, 1986

Claims (6)

[Claims] (1) A microstrip line in which a strip conductor is provided on the surface of a ground conductor layer through a dielectric layer made of polyolefin resin, and the ground conductor layer is located on the opposite side of the ground conductor layer from the side on which the dielectric layer is formed. A microstrip line characterized in that a resin layer made of polyolefin resin is also formed on the surface. (2) The microstrip line according to claim 1, wherein the dielectric layer and the resin layer have directionality, and are superimposed so that their directionality is perpendicular to each other. (3) The thickness of the resin layer is 80 to 120% of the thickness of the dielectric layer
A microstrip line according to claim 1 or 2. (4) The microstrip line according to any one of claims 1 to 3, wherein the surface on which the strip conductor is formed is coated with a thin resin film. (5) The microstrip line according to any one of claims 1 to 4, which is a microstrip line antenna. (6) The microstrip line according to claim 5, wherein the strip conductor is formed in a crank shape.