JPH0337278Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to the improvement of a radio wave absorber, and more specifically, to a light-weight radio wave absorber with excellent heat resistance.

[Conventional technology]

Figures 2, 3, and 4 show cross-sectional views of conventional radio wave absorbers. Figures 2 and 3 are dielectric material radio wave absorbers, and Figure 4 is magnetic material radio wave absorbers. It shows the body. In FIG. 2, 1 is a dielectric material such as foamed polystyrene, foamed urethane, or rubber mixed with graphite powder, and 2 is a conductor plate. In FIG. 3, reference numeral 1' denotes a dielectric material in which dielectric materials 1a, 1a', 1a'', and 1a made of the above-mentioned dielectric material and graphite powder are stacked in layers, each having a different dielectric constant by changing the content of graphite. In Figure 4, 3
is a magnetic material made by powdering an oxide magnetic material (sintered ferrite) and mixing it into rubber.

Next, the operation will be explained. In the dielectric material radio wave absorber shown in Figs. 2 and 3, the conduction loss of graphite powder is used, and in the magnetic material radio wave absorber shown in Fig. 4, due to the action of the oxide magnetic material,
It functions as a radio wave absorber.

In a dielectric material radio wave absorber, when a radio wave is incident on a flat plate from free space, a large reflection occurs, so in order to match it with free space, it is processed into a tapered shape as shown in Figure 2. As shown in FIG. 3, materials with different dielectric constants are layered.

[Problem that the invention attempts to solve]

As mentioned above, conventional radio wave absorbers are composed of a dielectric material such as styrofoam, urethane foam, or rubber mixed with graphite powder, and a magnetic material made of powdered sintered ferrite mixed in rubber.
There were problems in that the heat resistance properties were not good and the weight was large.

This invention was devised to solve the above-mentioned problems, and the purpose is to obtain a radio wave absorber that has good heat resistance, is lightweight, and has good reflection attenuation characteristics.

[Means for solving problems]

The radio wave absorber according to this invention uses carbon fiber-reinforced plastic with excellent heat resistance as the material constituting the absorber. Carbon fiber-reinforced plastic formed into a rod or needle shape is placed on a carbon fiber-reinforced plastic plate. It is constructed by attaching it.

[Effect]

The radio wave absorber in this invention is made by attaching a plurality of carbon fiber-reinforced plastic plates formed into the shape of a plurality of rods or needles onto the carbon fiber-reinforced plastic plate vertically or tilted at an arbitrary angle. By configuring the cross-sectional shape connecting the tips of the molded carbon fiber-reinforced plastic into a wave shape, the dielectric constant can be gradually changed in the direction of propagation of radio waves, making it easy to match with free space. can.

Furthermore, since the radio wave absorber in this invention is constructed of carbon fiber reinforced plastic, it has excellent heat resistance and is lighter in weight than conventional dielectric material radio wave absorbers and magnetic material radio wave absorbers.

〔Example〕

FIG. 1 is a block diagram of a radio wave absorber showing an embodiment of this invention. In FIG. 1, 4 is cylindrical (it may also be in the shape of a cone, cylinder, polygonal pyramid, or polygonal column).
5 is a carbon fiber reinforced plastic rod, and 5 is a carbon fiber reinforced plastic plate.

A cylindrical carbon fiber-reinforced plastic rod 4 is attached to a carbon fiber-reinforced plastic plate 5 vertically or tilted at an arbitrary angle using an adhesive or the like, and the cross-sectional shape connecting the tips of the carbon fiber-reinforced plastic rod 4 is shaped into a sawtooth, sine wave, or sine wave. It is configured to have a waveform such as a cosine wave, a combination of semicircles and semicircles, a quadratic curve, or a combination with a higher-order curve.

As shown in Fig. 1, the radio wave absorber of this invention has a wave-shaped cross-sectional shape connecting the ends of the carbon fiber reinforced plastic rod 4, so that The equivalent permittivity can be gradually increased, as shown in Figures 2 and 3.
Similar to the conventional dielectric material radio wave absorber shown in the figure, matching with free space can be easily achieved.

Further, its function as a radio wave absorber uses the conductor loss of carbon fiber, and is similar to conventional dielectric material radio wave absorbers.

Furthermore, although the explanation has been made using a rod-shaped carbon fiber reinforced plastic, a needle-shaped one may also be used.

In the embodiment shown in FIG. 1, a case is shown in which the carbon fiber-reinforced plastic cylindrical rod 4 and the carbon fiber-reinforced plastic plate 5 are used. In order to improve the performance, the radio wave absorber can also be constructed by lining the carbon fiber reinforced plastic plate 5 with a conductive plate.

In addition, although Fig. 1 shows the case where the cross-sectional shape is wavy, by making the cross-sectional shape connecting the tips also waveform in the depth direction, alignment with free space can be easily achieved. , further improvement in characteristics can be achieved.

[Effect of idea]

As described above, according to this invention, a light-weight radio wave absorber with excellent heat resistance can be easily obtained with a simple structure in which a plurality of carbon fiber reinforced plastic rods are attached to a carbon fiber reinforced plastic board. There is.

As an application of this idea, it can be installed around the sub-reflector of a multi-reflector antenna to shield radio waves leaking from the sub-reflector, and it can be applied to suppress scattered waves by attaching it to a pillar that supports the reflector. Yes, we can expect great effects.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing a radio wave absorber according to an embodiment of this invention, Figure 2 is a sectional view showing a conventional dielectric material radio wave absorber processed into a tapered shape, and Figure 3 is a conventional layered radio wave absorber. FIG. 4 is a sectional view showing a dielectric material radio wave absorber, and FIG. 4 is a sectional view showing a conventional single-layer magnetic radio wave absorber. In the figure, 1, 1', 1'', 1a, 1a', 1
a″, 1a is a dielectric material, 2 is a conductive plate, 3 is a magnetic material,
4 is a carbon fiber reinforced plastic cylindrical rod, and 5 is a carbon fiber reinforced plastic plate. In addition, in the figure,
The same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) In a radio wave absorber made of a dielectric material, carbon fiber reinforced plastic is used as the dielectric, and the carbon fiber reinforced plastic formed into a rod or needle shape is used as a plate. A radio wave absorber attached to carbon fiber reinforced plastic, characterized in that the cross section connecting the tips of rod-shaped or needle-shaped carbon fiber reinforced plastic plates is configured in a wave-like shape. (2) The shape of carbon fiber-reinforced plastic that can be formed into a rod or needle shape is a cone, cylinder, polygonal pyramid,
The radio wave absorber according to claim (1) of the utility model registration, characterized in that it is constituted by a polygonal prism or the like. (3) A request for registration of a utility model characterized in that the waveform shape is a sawtooth wave, a sine or cosine wave, a combination of semicircles and semicircles, a quadratic curve, or a combination with a higher-order curve. The radio wave absorber described in scope (1).