JPS60132407A - Multi-curved, stepped parabolic antenna - Google Patents

Abstract

PURPOSE:To obtain a parabolic antenna which has a form approximate to a plane and can be easily carried by using a fluting surface consisting of plural parabolic curved surfaces having same axis and focal point with different focal distances to form a reflecting surface of the parabolic antenna. CONSTITUTION:Parabolic curved surfaces 11-12, 13-14, 15-16 and 17-18 having the same focal point as a center axis 2 are connected by means of stage parts 12-13, 14-15 and 16-17 respectively. The differences among these parabolic surfaces are set at an integer multiple as much as 1/2lambda of a received radio wavelength lambda, and therefore corners 12-18 are set on a plane rectangular to the axis 2. As a result, the coincidence is secured among phases which are reflected by plural parabolic curved surfaces and reach the same focal point. A through hole 10 is provided to each stage part to shunt the wind pressure as well as the rainwater, etc. Therefore a parabolic antenna with stages has a form approximately equal to a plane and is suited to the carrying and assembling purposes with high resistance to the wind pressure, rainwater and heat reaction respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in parabolic antennas for receiving radio waves.

Parabolic antennas are widely used for receiving telephone microwaves and stellar radio waves for radio astronomy, and recently they have been used for receiving communications satellites, direct satellite broadcasting high-definition television, pulse code modulation broadcasting, still image broadcasting, etc. has also become widely used.

Prior Art Regarding conventional parabolic antennas, the standard type is shown in Figure 1 (A) (front view), (0) (side view), and the offset type is shown in Figure 2 (A) (front view), (0). (Side view)
are shown respectively. Both have a single reflecting surface (1) consisting of a parabola rotating surface, which focuses radio waves in the direction of the central axis (2) of the parabola to the focal point (F) of the parabola, and directs it to the waveguide (4) (B) of the receiving section. S converter).

Standard type parabolic antennas are symmetrical about the central axis of the parabolic curve, and the radio waves from the receiver are cast in the center of the reflecting surface facing the direction of radio wave incidence, but the offset type casts a shadow on one side of the parabolic curved surface from the central axis. The shadow of the radio waves in the receiving section is removed from the reflection ■], and the entire reflective surface is effectively utilized.

Such conventional parabolic antennas use a rotating parabolic curved surface as a reflecting surface, so they have to be large-volume three-dimensional structures, and when actually used, they are not necessarily of a fixed type and must be transported and assembled. There may be a need,
Also, since it is exposed to the atmosphere outdoors, it will need to withstand the wind pressure from strong winds and the thermal stress caused by partial heating from solar heat rays. For these conditions, it is more advantageous to have an overall shape that is close to a planar shape.

Purpose of the Invention The present invention divides the radio wave reflecting surface of a parabolic antenna into a plurality of parts so that it can be transported, assembled, and adapted to wind pressure, rain water, and heat resistance stress by dividing the radio wave reflecting surface of the parabolic antenna into a substantially flat shape. The purpose of this invention is to provide a parabolic antenna structure with good radio wave reception performance.

Structure of the Invention The present invention provides a parabolic antenna having a reflecting surface that receives radio waves and focuses them on a focal point.
It is characterized by being composed of a step moon surface consisting of a step surface, and a plurality of parabolic curved surfaces of the step surface are formed so that the phases of radio waves that are reflected by each surface and reach the same focal point are approximately the same. The main subject is a multi-curved, stepped parabolic antenna.

In the case of a general, single-plane parabolic antenna, if we take two radio waves that take different paths among the focused radio waves to the focal point, they naturally have the same path length and the same phase, Therefore, the focused radio waves become mutually reinforcing.

In the structure of the present invention, the reflecting surface is composed of a plurality of parabolic curved surfaces with different focal lengths, or even in the case of such a compound curved surface configuration, the plural parabolic curved surfaces are
It is possible to make the radio waves focused on the same focal point from each surface have the same phase, and by doing so, it is possible to ensure the same reception function as the single-plane parabolic antenna. That is, in order to match the phases of the focused radio waves from each of the multiple curved surfaces C1, as shown in FIG. Difference (X) or %λxn(
(λ: wavelength, n: integer). The reason is explained as follows. In Figure 8, the central axis (
2), two parabolic curved surfaces (7 m
) (7m+1) and incident radio wave (5m) (5m+
Considering the case of 1) and 1) being reflected and reaching the focal point fr), two incident radio waves (5m) (5111+1)
Let U be the difference in path length in the direction of incidence of , and W be the difference in path length in the direction of reflection of the two reflected radio waves (6m) (6m-+-+), then (5m) → ( 6m)
The difference in total path length between the two chamber waves and (5m-+-+)→(5m+4) is denoted by
-4-w) has a length approximately corresponding to an integer multiple of the wavelength λ, the two waves match in phase and emphasize each other. By the way, due to the geometrical properties of parabolic surfaces, the above 2.
The difference in path length between two radio waves (u-1-w) is the difference between the two parabolic curved surfaces (7m) (7m+
1) (#m am+1(,=x))
This means that the phase or focus of both radio waves is equal to twice that of the radio waves mentioned above.
This means that λ×n.

In addition, when designing a reflective surface consisting of multiple parabolas as shown in Figure 8, the width of each curved surface constituting the reflective surface (
S) and angle (0) or step height h (=i=W) are required, or these values are determined by the angle type of plane P-P', the wavelength The distance between the bars is an integer n
It depends on the value of , and if these values are given in advance as specifications, they can be calculated.

Examples Next, based on examples, a multi-curved surface and a stepped parapolar plate of the present invention will be described.
The structure and function of the antenna will be described.

Figure 4 shows a conventional standard parabolic antenna (A) and a standard multi-curved stepped parabolic antenna of the present invention (0) (
(→ is a front view) (stomach)
, Naka) both focus the radio waves at the same focal position (F), or the conventional (A) has a three-dimensional shape, whereas the compound curved surface and stepped lapola of the present invention・The antenna (b) has an approximately disk-shaped planar shape (it is contained in one piece).

FIG. 5 (a), (b), and (c) show the standard double curved surface of the present invention.
1 shows an example of a stepped parabolic antenna; Same figure (a)
is a plan view, (b) is a central sectional view, and (c) is a sectional view taken along line A-A. In the figure, QIJ-(121, Ji-α→,
It is a parabolic curved surface that has the same center axis (2) and focal point (F) subtracted by αQ-θ・, αη-θ, and between each of them is (2)
-a field, a→-05, connected at the step of μe-(17). For example, if a microwave with a wavelength λ=25.27 mm is to be received, the difference (X) in focal length between the parabolic surfaces is approximately 12% of the wavelength. ．． 63! 5. ” or an integer multiple thereof. In this example, the corner scream α410f19 (, L81, (130F; J
(1η) are each formed on a plane perpendicular to the central axis (2). Also, the stepped portions (121-(13, g4
)-Q51, QQ-αη has a through hole 0Q or is it provided?
This functions effectively to release wind pressure and drain water such as rainwater.

Figure 6 shows a conventional offset parabolic antenna (a)
FIG. 4 is an explanatory diagram showing a comparison between the offset type compound curved surface, stepped/lapolar antenna (b) ((c)) of the present invention. (a) and IL-? ) have the same focal position (uniformity), and the projection onto the reflecting surface of the receiving section is avoided by offset arrangement, or in this case, the one of the present invention has a substantially flat surface due to the multi-curved surface and stepped structure. It fits in the shape of.

FIG. 7 is a perspective view of the offset type multi-curved stepped parabolic antenna of the present invention. In the same figure, (4
)−□□□, So−(C), 1→θ are parabolic surfaces that share the central axis (2) and the focal point (force, and the distance between them is ) are connected at the stepped part.

For example, if microwaves with wavelengths λ-25, 27~ are to be received, the difference in focal length (X
) is approximately % wavelength. 12.68jIl! or an integral multiple thereof. In this example as well, corners (G), 4 (A), and Cl4 (A) of the stepped portion are each set to lie approximately on a plane, so that the front shape is approximately elliptical. It's Nishide.

Effects of the Invention The multi-curved, stepped parabolic antenna according to the present invention has many advantages. In other words, when manufacturing a metal plate by pressing a die, the depression depth of the die can be set shallow (the depth of 70 mm in the conventional product was reduced to 125 mm in this example). This can extend the life of the mold. Also,
Compared to conventional parabolic antennas, there is less splinter back due to press stamping, so the shape as printed is maintained, and performance does not deteriorate due to deformation. In particular, when a through hole is provided in the stepped portion of the nonconforming surface, rainwater or the like is prevented from accumulating on the reflective surface, and it is also effective in reducing wind pressure.

Due to the stepped surface structure, it is easy to ensure high strength, and the thickness of the Soko metal plate can be reduced. In addition, since the overall shape can be made into a flat shape, there is little wind pressure resistance, and it is easy to incorporate electric heaters for snow melting.

As is clear from the above, the multi-curved, stepped parabolic antenna of the present invention can be installed in a small size, and is easy to transport, assemble, and withstand wind pressure.
It can be said that it is a parabolic antenna that is suitable for heavy rain water and acclimatization stress, and has extremely excellent radio wave reception performance.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of a standard type parabolic antenna, (A) is a front view, (A) is a side view. Figure 2 is an explanatory diagram of an offset type parabolic antenna, (A) is a front view, ( B)
is a side view. Fig. 3 is a diagram illustrating how radio waves are reflected on a multi-parabolic curved surface, and Fig. 4 (a) is a front view illustrating a conventional standard parabolic antenna. (c) is a side view of the same figure (b). Figure 5 shows a standard type multi-curved surface according to the present invention, tiered parahora,
Figures showing one embodiment of the antenna, (A) is a plan view, (O) is a central sectional view of Figure 5 (A), and (C) is A-A of Figure 5 (A).
A-line arrow view... is a one-sided view. Figure 6 (a) is a front view illustrating a conventional offset type parabolic antenna, (b) is a front view illustrating a double parabolic antenna of the present invention, and (c) is a front view of the same figure (b)). Side view. FIG. 7 is a perspective view illustrating an embodiment of an offset type multi-curved stepped parabolic antenna according to the present invention. 1: Parabolic reflective surface, 2: Central axis, 4: Waveguide, 5: Incident radio wave, 6: Reflected radio wave, 7: Reflective surface, F: Focus Applicant Aihara Machinery Co., Ltd. (A) (B) (C) ) Figure 7

Claims (2)

[Claims] (1) In a parabolic antenna having a reflecting surface that receives radio waves and focuses them on a focal point, the reflecting surface is composed of a stepped surface consisting of a plurality of parabolic curved surfaces that are coaxial and confocal and have different focal lengths; A stepped parabolic antenna with a multi-curved surface, characterized in that the phases of radio waves that reach the same focal point by contradicting each surface of the parabolic curved surface of the parabolic curved surface are almost the same as each other. (2) In a parabolic antenna that has a reflecting surface that receives radio waves and focuses them on a focal point, the reflecting surface is formed of a stepped surface consisting of a plurality of parabolic curved surfaces that are coaxial and confocal and have different focal lengths; A through hole is provided in the step between adjacent parabolic curved surfaces of the attached surface, and multiple parabolic curved surfaces are formed so that the phases of the radio waves that are reflected by each surface and reach the same focal point are approximately the same. Features a parabolic antenna with multi-curved surfaces and stepped sections.