JPH04207606A - Device for preventing transmission loss of dielectric with respect to radio wave - Google Patents

Abstract

PURPOSE:To reduce a transmission loss and to miniaturize the dielectric itself by providing a flat plate conductor element on a film, and adhering the element onto the dielectric to delay the phase of a radio wave. CONSTITUTION:A flat plate conductor element 18 is formed to one face of a flat plate 16. The flat plate conductor element 18 is formed to be disk-shape and each of the flat plate conductor elements 18 is arranged at the interval of nearly lambda/2 of a wavelength lambda of a satellite broadcast wave to be received, and the diameter is made less than lambda/2. Part of a radio wave made incident in the flat plate conductor element 18 on the flat film 16 is delayed and made incident in a dielectric substance 12 from an incident face of the dielectric substance 12, since the flat plate conductor elements 18 are arranged at a prescribed interval and the size is made smaller than a half of the wavelength of the radio wave so that a 1st phase delay wave and a 2nd phase delay wave are opposite to each other, the 1st phase delay wave and the 2nd phase delay wave are canceled together. Thus, the transmission loss is reduced, miniaturization and light weight are attained and the mount is simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a preventive device that prevents transmission loss caused by a dielectric material such as a window glass when receiving radio waves through the dielectric material. be.

[Prior Art] Generally, t! As shown in the PJB diagram, when receiving radio waves through the window glass 10, a transmission loss occurs, but this transmission loss can be reduced by adjusting the thickness t of the window glass 10. That is, the radio wave A that is directed toward the window glass 10 at an incident angle θ is transmitted from one surface 10a of the window glass lO to C.
The remaining light enters the window glass 10, is refracted across the refraction angle θ, and heads in the b direction. This refracted radio wave is reflected in the C direction on the other surface 10b of the window glass 10, and the rest of the wave flies out from the other surface 10b in the direction d outside the window glass 10. Then, the radio waves in the C direction are reflected from one surface 10a in the C direction on the other surface 10b side, and the remaining waves fly out from the one surface 10a in the external direction f. This f-direction radio wave has a phase delay while reciprocating within the window glass 10. On the other hand, a radio wave A' parallel to the radio wave A is reflected by one plane 10a, and this is in the same direction as the radio wave in the f direction. Therefore, if the phase difference between the radio wave in the direction a' and the radio wave in the f direction is 180 degrees, they will cancel each other out, and the energy of the radio wave A' will be approximately C.
Head in the direction.

In order to set the phase difference between the radio waves in the a' direction and the f direction to be 180°, the detailed calculation formula may be omitted or the window glass 1
The thickness t of 0 is t=λ/2 (dew s+n"fJ l). However, input is the wavelength of the received radio wave, and ε is the relative permittivity of the window glass 10. ε is the window glass 10. For glass 10, 4 to 7
For example, when receiving satellite broadcasting in Japan, θ1
is less than 50°, so the above formula is 7=in/2\"
- becomes---λ'/2. However, λ′ is the window glass IO
It is the wavelength within. If you calculate this, t will be as thick as 5 to 6 squares. Generally, the window glass 10 has a thickness of 2 to 4 mm.
In this case, the phase difference between the radio waves in the a' direction and the radio waves in the f direction was 360°, causing a large transmission loss as shown in FIG. 9.

Therefore, a conventional approach has been to attach a dielectric material having a dielectric constant close to that of the window glass 10 to make the thickness of the window glass IO equivalently close to λ'/2 to reduce the transmission loss.

[Invention or problem to be solved @] However, when attaching a dielectric to the window glass IO as described above, the thickness of the dielectric must be changed based on the thickness of the window glass 10. Moreover, the weight of the dielectric material itself is quite large, and unless a strong adhesive is used, the dielectric material may peel off from the window glass. Another problem is that if the dielectric is bonded with a strong adhesive, it will be difficult to remove the dielectric when it is no longer needed, and the dielectric plate will be large, making it difficult to transport.

An object of the present invention is to provide a transmission loss prevention device that solves the above problems by providing a flat conductive element on a film and pasting this on a dielectric to delay the phase of radio waves. do.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a flat film provided on a dielectric material through which radio waves pass, and a flat film provided on one surface of the film at a predetermined interval. and a planar conductive element having a diameter smaller than 1/2 of the wavelength of the radio wave.

[Function] According to the present invention, a part of the radio waves incident on the planar conductive element on the flat film is delayed and enters the dielectric from the incident surface of the dielectric, and then passes through the reflective surface opposite to the incident surface. It is reflected by the incident surface, refracted by the incident surface, and emitted to the outside. The phase of the radio wave is delayed during the movement from the incident surface to the reflective surface and from the reflective surface to the incident surface, and the phase is further delayed when passing through the planar conductive element on the flat film. This total phase delay is defined as a first phase delay. On the other hand, the remaining part of the radio wave incident on the flat conductor element is reflected by the incident surface, and the phase is also delayed. Assuming that this amount of delay is the second phase delay, planar conductive elements are provided at a predetermined interval so that the first phase delay and the second phase delay are opposite in phase. Since the size is smaller than /2,
The first phase delay and the second phase delay cancel each other out, and transmission loss can be prevented.

[Example] The transmission loss prevention device 11 of this example is attached to, for example, a window glass 12 as shown in FIG. As shown in FIGS. 1 and 2, a flat film 16, for example, a polyethylene film with a thickness of about 300 mm is provided. Note that the size of this flat film 16 is determined according to the size of the satellite broadcast receiving antenna 14.

A flat conductive element 18 is formed on one side of the flat film 16 by various known techniques such as etching, printing, or vapor deposition. This flat conductor element 18
are formed, for example, in the shape of a disk, and each has a predetermined interval, for example, the wavelength input (12G) of the satellite broadcast to be received.
Hz), and the diameter is smaller than 172 people, for example 0.3 to 0.3
There are said to be five people.

As shown in FIG. 3, this transmission loss prevention device 11 is attached to a window glass 12 using an adhesive tape or the like. In order to prevent the adhesion of raindrops, etc., it is preferable to attach it to the indoor side surface of the window glass 12.

In addition, in order to prevent the influence of the dielectric constant of the window glass 12, if the thickness of the window glass 12 is approximately 3 CI, it is necessary to attach the film directly to the film surface on the opposite side from where the disc-shaped conductive element is provided. The thickness of the window glass 12 is about 1~2■I
In order to match the phase in this case, it is desirable to provide some space between the glass surface and the film surface on the opposite side to where the disc-shaped conductor element is provided. Note that in FIGS. 2 and 3, the thickness of the flat conductor element 18 is considerably exaggerated.

Next, how the transmission loss can be prevented by the transmission loss prevention device 11 will be explained with reference to FIGS. 4 and 5. In addition, in FIG. 4, in order to simplify the explanation, it is assumed that the transmission loss preventive device 11 is attached to the outdoor side of the window glass 12. The incident radio wave E passes through the transmission loss prevention device 11 and becomes a radio wave E iz whose phase is delayed by θ as shown in FIG. It travels to the right end, is reflected, and travels to the left end. Let this radio wave be E rg. The phase of the radio wave E, 1 or δ while it travels from the left end to the right end
Due to the delay and the dielectric constant, the radio waves E, , have an opposite phase.

After all, when it advances to the right end, the phase difference of E88 becomes π+δ. Also, while traveling from the right end to the left end, the phase is delayed by δ, and the phase difference between the radio wave Erg and E LK is π+2
It becomes 6. This radio wave Er8 undergoes a phase delay of θ when passing through the transmission loss prevention device 11, and becomes E rg'. On the other hand, a part of the radio wave E1' is reflected by the transmission loss prevention device 11 and the right end of the window glass 12, and becomes a radio wave E, which is delayed in phase from the radio wave E by Φ. Φ and θ become larger as the diameter of the flat conductor element 18 becomes larger. Therefore, by changing the diameter of the flat conductor element 18, E rfg and E rx' can be made to have opposite phases. Therefore, the reflected waves E,,' can be canceled out, and the transmission loss can be reduced.

Thickness 3■ when changing the diameter of the flat conductor element 18
FIG. 6 shows the change in transmission loss of the window glass 12. In the figure, the incident angle of the radio wave E is 30°, and the interval between each flat conductor element 18 is 1:1 mm (about λ/2). In the same figure, the dashed-dotted line indicates the case where the flat conductor element 18 is not provided, the dashed-dotted line indicates the diameter. 91 is shown. As is clear from this, the diameter is 0.28 Å.
If the number is above and less than 0.36, a transmission loss that is sufficiently practical can be obtained.

Furthermore, as the interval between the flat conductor elements 18 is made smaller, the amount of reflection of the transmission loss prevention device 11 itself can be increased and the amount of transmission can be decreased.
Should I set the interval so that it cancels out the amount of reflection from the glass?If the diameter of the flat conductor element is 0.35, then it is about 172.
People are preferable.

In the above embodiments, the flat conductive element 18 is shown to be circular, but it does not have to be circular; for example, as shown in FIG.
It may have various shapes as shown in a) to (e),
The maximum width of each portion needs to be smaller than I/2, since the amount of reflection increases rapidly when the width becomes larger than I/2. In the above embodiments, the dielectric loss preventive device is provided on a window glass or can be used in a radome of a parabolic antenna.

[Effects of the Invention] As described above, according to the transmission loss prevention device according to the present invention,
It is possible to reduce transmission loss, and since the structure is such that a flat conductor element is provided in a film shape, it is small and lightweight, easy to install, and easy to transport.

[Brief explanation of the drawing]

Fig. 1 is a plan view of an embodiment of the transmission loss prevention device according to the present invention, Fig. 2 is a side view of the embodiment, Fig. 3 is a diagram showing the usage state of the embodiment, and Fig. 4 is the same implementation. FIG. 5 is a vector diagram of the operating state of the example, FIG. 6 is a transmission loss vs. frequency characteristic diagram using the size of the flat conductor element as a parameter in the example, and FIG. The figure shows a modified example of the flat conductor element used in the same example, Figure 8 is an explanatory diagram of the state in which radio waves are transmitted through glass, and Figure 9 is a diagram showing the relationship between glass thickness and transmission loss. It is. 12... Window glass (dielectric material), 16... Flat film, 18... Flat conductor element. Patent applicant DAYX Antenna Co., Ltd. Agent
Person Satoshi Shimizu Number 1 of 2 people (
2)! IA2 IS! ] b No. 3 Concave No. 4 Akira Seki 5 No. 6 (2)

Claims (1)

[Claims] (1) A flat film provided on a dielectric material through which radio waves pass, and a planar conductive element provided on one side of this film at a predetermined interval and having dimensions smaller than 1/2 of the wavelength of the radio waves. A radio wave dielectric transmission loss prevention device comprising: