JPS58175302A - Antenna device - Google Patents

Abstract

PURPOSE:To obtain a sharp beam pattern of electric waves, by providing an apex matching plate made of a material that reflects a part of the electric wave to a reflector and transmits the rest electric waves. CONSTITUTION:The electric wave is radiated from a primary radiator 1 to a reflector 2. An apex matching plate made of a dielectric material is provided on the surface of the reflector 2 and transmits the greater part of the incident electric waves. The greater part of the electric waves incident to the plate 3 are converted into planar waves after passing through the plate 3. Thus it is possible to increase sufficiently the size of the reflecting area of the plate 3 in comparison with the wavelength. As a result, a sharp beam is obtained for the electric wave reflected by the plate 3.

Description

[Detailed description of the invention] This invention is used in the microwave band and MIJII
The present invention relates to an improvement of an antenna device consisting of a reflecting mirror, a primary radiator, and a vertex matching plate. As shown in Fig. 1, in such an antenna device, a -order radiator (1st
) is reflected by the reflecting mirror (2) and then returns to the primary radiator fi+. Therefore, the power of the radio waves returned from the primary radiator +11 iC? In order to reduce the size, a metal apex alignment plate (31) is provided in the center of the reflector (2) to reflect 1 reflection*+21 and create a -order radiator+
The radio waves reflected at the top alignment plate (3) returning to 11 were used to cancel out the radio waves. In this case, the vertex matching plate (
Since the size of the radio wave reflecting surface at 3) is small compared to the wavelength, the radiation pattern (4) of the radio waves reflected at the vertex matching plate (31) has a very broad shape, and only a portion of the above can be interpreted as a first-order Other radio waves that did not return to the radiator +11 were deteriorating the entire radiation pattern of this antenna device.Also, in order to make the entire beam of radio waves reflected by the vertex matching plate (3) sharp.

If the size of the radio wave reflecting surface in the apex matching plate (3) is made larger than the growth, a large blocking will occur in the center of the 9 reflecting mirrors (21), so by providing the apex matching plate (3), this antenna device There was a drawback that the pattern deteriorated.

This invention overcomes all of the above-mentioned drawbacks of the conventional technique by constructing the apex matching plate with a dielectric material or wire mesh that reflects a portion of the incident radio waves and allows the remaining waves to pass through the radio waves 11'.
This will be explained in detail below using the drawings.

Figure 2 shows this invention! J! This is a diagram showing an example, in which the vertex matching plate +31 has a radio wave reflecting surface that is sufficiently large compared to the ff length.
i. It is made of a dielectric material that allows most of the incident radio waves to pass through and reflects the remaining radio waves.

With this configuration, the vertex alignment plate (3)
Most of the nine electric waves incident on the antenna device are converted into plane waves by reflection fi+21 after passing through the apex matching plate (3), so that the apex matching plate (31 The size of the radio wave reflecting surface can be made sufficiently larger than the length t-a.Therefore, the radio wave beam reflected by the apex matching plate (3) can be sharpened, so that the -order radiator (1
) The amount of radio waves radiated in directions other than those shown in FIG.

Furthermore, as shown in FIG. 2(b)'vc, the vertex alignment plate (3
) should be aligned with the other side of the radio waves incident on the vertex matching plate (3) when considering this antenna device as the entire transmitting antenna, that is, rI in the phase of the -order radiator (1):) +51 'ff is a spherical surface centered on the vertex matching plate (1G of radio waves reflected at 31 + '(j
- Since it can be concentrated on the second radiator fl+, the power of the radio wave reflected by the vertex matching plate (3)? , Figure 2 (a
) can be reduced compared to the case where the surface of the vertex matching plate (3) is flat, and the amount of deterioration of the radiation pattern of this antenna device can be further reduced.

Figure 2<c>rrx Main reflector (2a) and sub-reflector (2b)
) and a −order radiator fl+, the present invention is implemented in a Gregorian type antenna device. The sub-reflector (2b) is a spheroidal mirror whose focal points are the phase center (5) of the -order radiator (1) and the focal point (7) of the main reflector. A vertex alignment plate (3) made of a dielectric material is provided on the reflective surface side of the sub-reflector (2b). With such a configuration, the electrons reflected by the vertex matching plate (3) can be concentrated in the primary radiator +11, so that the radiation pattern of the antenna device is completely degraded.

The radio waves reflected by the sub-reflector (2b) and returned to the primary radiator (1) are all canceled out by the radio waves reflected by the vertex matching plate (3) and returned to the primary radiator fi+. can. Note that similar effects can be obtained in a Cassegrain type antenna device by similarly providing the vertex matching plate according to the present invention on the sub-reflector.

FIG. 3 is a diagram showing another embodiment of the invention.

Main reflector (2a), sub-reflector (2b) and -order radiator +
In a Cassegrain-type antenna device composed of L +
This is the one provided in a). The surface of the vertex alignment plate (3) is the focal point (7) of the main reflecting mirror (2a) consisting of a one-rotation parabolic mirror
) is a spherical surface with its center at the center. With this configuration, the radio waves radiated from the primary radiator (1),
The radio wave reflected by the vertex matching plate returns to the primary radiator 1υ after being reflected by the sub-reflection Q(2a), so it is possible to obtain the same effect as the effect of the present invention described above. can. Note that similar effects can be obtained even when the present invention is applied to a Gregorian type antenna device.

Above, we have explained the case where a dielectric material is used as the material of the vertex matching plate that reflects a part of the incident radio wave and passes the remaining radio wave. A similar effect can be obtained by using a metal plate with sufficiently large holes.

FIG. 4 is a diagram showing another embodiment of the invention.

Main reflector (2a), sub-reflector (2b) and -order radiator C
In a Cassegrain-type antenna device composed of The surface of the apex matching plate (3) made of a metal plate on the back side of the reflective surface of the mirror (2b) is made into a spherical surface centered on the phase center of the primary radiator. With this configuration, the radio waves emitted from the -order radiator 11) and reflected by the sub-reflector (2b) are reflected by the main reflector (2a) and become flat ml waves. Further, the radio waves radiated from the -order radiator +13 and passed through the sub-reflection * (2b) are reflected by the vertex matching plate (3) and then returned to the -order radiator +13. The radio wave (6) reflected by the vertex matching plate (3) is -
Since the radio waves reflected by the sub-reflector (2b) and returned to the primary radiator 11) can be concentrated on the secondary radiator Cυ without deteriorating the radiation pattern of the antenna device, the apex matching plate ( 3) It can be canceled by radio waves reflected by K and returned to the primary radiator H). It should be noted that the present invention has been described in the case where it is applied to a Gregorian type antenna device.

Similar effects can be obtained even when the present invention is applied to a Cassegrain type or parabolic type antenna device.

As explained above, in the antenna device of the present invention, the apex matching plate is made of a dielectric material that reflects part of the incident radio waves and allows the remaining radio waves to pass through, or of a wire mesh having holes that are sufficiently large compared to the wavelength. By doing this, the size of the radio wave reflecting surface on the apex matching plate can be made sufficiently large compared to the wavelength, and the radio waves reflected on the apex matching plate can be concentrated on the primary radiator. The radio waves reflected by one reflecting mirror and returned to the primary radiator can be canceled by the radio waves reflected by the vertex matching plate without deteriorating the radiation pattern of the antenna.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional antenna device, FIG. 2 is a block diagram of an antenna device according to the present invention, and FIGS. 3 and 4 are block diagrams of other embodiments of the antenna device according to the present invention. In the figure, (1) is a -order radiator, (2) is a reflective inkstone, (3
1 is a vertex matching plate, (4) is a radiation pattern, (5) is a phase center, (@) is a radio wave, and (7) is a focal point. Note that in FIG. 1, the same or corresponding parts are designated by the same reference numerals. Agent Makoto Kuzuno - Figure 1 Cl2) Figure 2 (b (C)

Claims (1)

[Scope of Claims] (1) An antenna device comprising one or more reflecting mirrors and a primary radiator, and having an apex matching plate on one or more reflecting mirrors, An antenna device characterized by being made of a material that reflects a portion of the incident radio waves through a vertex matching plate and allowing all of the remaining radio waves to pass through, and is provided on the reflective surface side of a reflecting mirror. (2) The surface of the vertex matching plate provided on each reflecting mirror corresponds to the wavefront of the radio wave incident on the vertex matching plate when the antenna device is considered as a total transmitting antenna. The antenna device according to item 1. (3) Either claim 1 or 2, characterized in that a dielectric, a wire mesh, or a metal plate with holes is used as a material that reflects a part of the incident radio waves and allows the remaining radio waves to pass through. The antenna device described in . +41 In an antenna device that is separated from one or more reflecting mirrors and a primary radiator and has an apex matching plate on one or more reflecting mirrors, partial total reflection of the radio waves incident on the reflecting mirrors occurs. The antenna device is made of a material that allows the remaining electricity to pass through, and is characterized in that an apex matching plate made of a metal plate is provided on the back side of the reflecting surface of the reflecting mirror. (5) Each reflection f#! Claim 4 is characterized in that the surface of the apex matching plate provided in the apex matching plate coincides with the surface of the radio wave incident on the apex matching plate when the antenna device a1 is considered as a transmitting antenna. antenna device. (61 Part of the incident radio wave is totally reflected and the remaining radio wave +111i
- An antenna device according to any one of claims 4 and 5, characterized in that a dielectric material, a wire mesh, or a perforated metal sheet metal is used as the material for passing.