JPS605618Y2 - power supply device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a power feeding device consisting of a horn antenna and a flat reflecting mirror.

First, a conventional power supply device will be explained based on FIG.

In Figure 1, 1 is a horn antenna, 2 is its input end, 3 is a plane reflector, 4 and 4' are incident waves entering the plane reflection mirror from the horn antenna, and 5 and 5' are plane reflections. This is a reflected wave from a mirror.

Further, θi and θr are the incident angle and the reflection angle, respectively, and are the angles formed by the normal line on the plane reflecting mirror 3, the incident wave, and the reflected wave.

The plane reflector 3 is placed close to the horn antenna 1 at an arbitrary inclination, and the radio waves radiated by the horn antenna 1 are incident on the plane reflector 3 at an incident angle θi, and are reflected so as to satisfy the following equation. do.

θi=θr (1) Usually, the mirror system of a power supply device or an antenna device is designed using a geometrical optics method.

However, since radio waves have a wider electric field distribution than when considered from the perspective of geometrical optics, the paths of the incident wave 4' and the reflected wave 5' indicated by dotted lines in Figure 1 are actually solid lines. The incident wave 4 and the reflected wave 5 are represented by , and they propagate in a predetermined direction while satisfying the first equation.

Therefore, when the plane reflector 3 is in the vicinity of the horn antenna 1, a part of the reflected wave 5 reflected at the closest part of the plane reflector 3 and the horn antenna 1 leaks into the horn antenna 1, and This has the disadvantage that it degrades the VSWR characteristic of the feeder as viewed from the input end 2 of the horn antenna 1 shown in FIG.

Therefore, as a method to eliminate the above drawbacks, the conventional method was to
As shown in the figure, a method has been adopted in which a radio wave absorber 6 is attached around the plane reflector 3 to absorb radio waves around the plane reflector 3.

Here, FIG. 2A is a front view of the power supply device, and FIG. 2A is a side view.

However, there is a limit value to the amount of radio waves absorbed by the radio wave absorber 6, and radio waves that cannot be absorbed leak into the horn antenna 1, degrading the VSWR characteristic of the power feeding device as viewed from the input end 2 of the horn antenna 1.

Furthermore, the weather resistance of the radio wave absorber 6 also deteriorates over time, adversely affecting the amount of radio waves absorbed, and the VSWR characteristic of the power supply device deteriorates over time.

Therefore, this invention is intended to improve these drawbacks.More specifically, in place of the radio wave absorber 6, a metal ring is attached around the plane refractory mirror 3, thereby reducing the reflected waves 5 by the plane reflector 3. VSWR seen from the input end 2 of the horn antenna 1 with a part leaking into the horn antenna 1
This is intended to prevent deterioration of characteristics.

An embodiment of this invention will be described below with reference to FIG.

1.2.3 in Figure 3 a and b and 4 and 5 in Figure 3 are the first
It is the same as that shown in Fig. 2, and 7 is a plane reflecting mirror 3.
It is a metal ring attached around the .

The outer shape of the plane reflecting mirror 3 is an oval shape, and the metal ring 7 is also shaped along the outer shape.

FIG. 4 shows the shape of the metal ring 7. FIG. 4a is a plan view of the metal ring 7, and FIG. 4a is a side view of the metal ring 7.

w and d shown in FIGS. 4a and 4b are the width and thickness of the metal ring 7.

The width W of the metal ring 7 is determined by the electric field strength around the plane reflector 3, and varies depending on the type and shape of the horn antenna 1 and the arrangement of the plane reflector 3.

Further, the thickness d of the metal ring 7 is determined so as to satisfy the following formula.

Note that equation (2) is an equation derived from the travel conditions as explained in FIG.

Here, λM is the free space wavelength at the center frequency in the frequency band used, and α is the angle between the center axis of the horn antenna 1 and the plane reflector 3, as shown in FIG. It is the angle measured counterclockwise from the central axis, and β is the angle between the axis perpendicular to the central axis of the horn antenna 1 and the incident wave 4 entering the plane reflector 3 from the horn antenna 1, which is orthogonal to the above. It is an angle measured counterclockwise from the axis.

Furthermore, α and β are 0°〈β〈180°, β−α1〈90
The value is selected to satisfy °.

Figure 5 is a detailed explanatory diagram of Figure 3, with symbols (1) and (2)
.

(3), (4), (5), and (7) are the same as those shown in Fig. 3, where 4" is the incident wave that enters the metal ring 7 from the horn antenna 1, and 5" is the incident wave that enters the metal ring 7. ring 7
This is a reflected wave that leaks into the horn antenna 1 from above.

In FIG. 5, by attaching a metal ring 7 with a thickness d that satisfies the second equation around the plane reflector 3,
The reflected wave 5'' from the metal ring 7 towards the horn antenna 1 and the reflected wave 5 from the flat reflector 3 towards the horn antenna 1 cancel each other because there is a kv difference in their travel distances.

Therefore, leakage of the reflected waves 5 from the periphery of the flat reflector with a metal ring into the horn antenna 1 can be eliminated, and deterioration of the VSWR characteristics of the power feeding device viewed from the input end of the horn antenna 1 can be prevented.

The case where the metal ring 7 is attached around the plane reflector 3 has been described above, but as shown in FIG. It is also possible to use a power supply device with a recess that satisfies
Furthermore, as shown in FIG. 6, the power supply device may have a convex portion around the plane reflecting mirror 3 whose height satisfies the second formula.

Furthermore, the cross-sectional shape of the metal ring 7 can be a metal ring 7 having a rectangular cross section 8 as shown in FIG. 7a, or a cross section 9 of a semicircular or similar shape as shown in FIG. It is also possible to use a metal ring 7 with a

Furthermore, as shown in FIGS. 7c and 7d, a part of the metal ring 7 is attached around the plane reflector 3, which is most effective for preventing the reflected waves 5 from leaking into the horn antenna 1. You can also do it.

Further, it may be a part of the metal ring 7 whose thickness is varied in the circumferential direction as shown in FIG. 8 at b, or a part of the metal ring 7 whose thickness is varied in the circumferential direction as shown in FIGS.

Here, Figures 8a and 8c are front views;
d is a side view.

Furthermore, in the second equation, it was stated that λM is the free space wavelength at the center frequency in the frequency band used.

However, λM can be determined by measuring the VSWR characteristics before the metal ring 7 is attached to the plane reflector 3.
It may also be a free space wavelength at a frequency where WR degradation is significant.

Although the case of a single power feeding device has been described above, the present invention can also be applied to an offset Cassegrain antenna as shown in FIG. 9 as an application example.

In FIG. 9, 10 is a sub-reflector made of a rotating quadratic curved mirror, and 11 is a main reflector made of a rotating parabolic mirror.

As described above, according to this invention, the metal ring 7 is attached to the periphery of the plane reflector 3 which is placed at an arbitrary inclination close to the front direction of the horn antenna 1, or the periphery of the plane reflector 3 is formed into a recess or the like. By deforming it into a convex portion, it is possible to prevent the reflected wave 5 from the plane reflector 3 from entering the horn antenna 1, and it is possible to improve the VSWR characteristic of the power feeding device as viewed from the input end 2 of the horn antenna 1. .

Furthermore, the metal ring 7 has superior weather resistance compared to the radio wave absorber 6, and has the advantage that its characteristics do not change even after long-term use.

[Brief explanation of the drawing]

Figures 1, 2a and 2b are block diagrams showing a conventional power supply device, and Figures 3a and 3b are block diagrams showing a power supply device of this invention.
Figures 4a and b are explanatory diagrams of the metal ring, and Figure 5 is the third
Detailed views of Figure 6, Figures 6a and b are views with the surroundings of the flat reflector modified in place of the metal ring, Figure 7 at by ct
ds Fig. 8 a, b, C, and d are diagrams showing various metal rings, and Fig. 9 is a configuration diagram of an offset Cassegrain antenna showing an application example of this invention. In the figure, 1 is a horn antenna, and 2 is a horn antenna. The feed end of the antenna, 3 is a flat reflector,
4, 4' are incident waves on the plane reflector, 4'' are incident waves on the metal ring, 5, 5' are reflected waves from the plane reflector, 5'' are reflected waves from the metal ring, 6 is radio wave absorption 7 is a metal ring, 10 is a sub-reflector made of a rotating quadratic curved mirror, and 11 is a main reflector made of a rotating paraboloid mirror. Note that the same or corresponding parts in the figures are denoted by the same reference numerals.

Claims (6)

[Scope of utility model registration request] (1) In a power feeding device consisting of a horn antenna and a plane reflector disposed at an arbitrary inclination close to the front surface of the radiation aperture of the horn antenna, a plane A power feeding device characterized in that a metal ring having a desired thickness and cross-sectional shape is directly provided to cancel reflected waves that enter a horn antenna by a reflecting mirror. (2) The power supply device according to claim (1), wherein the metal ring has a rectangular cross-sectional shape. (3) The power supply device according to claim (1), wherein the metal ring has a cross-sectional shape of a semicircle or a shape similar to this. (4) The method according to any one of claims (1) to (3) of the utility model registration claim, characterized in that the metal ring is formed along a part of the periphery of the flat reflecting mirror. Power supply device. (5) The power supply according to any one of claims (1) to (4) of the utility model registration claim, characterized in that the thickness of the metal ring changes in the circumferential direction of the flat reflecting mirror. Device. (6) The power supply device according to claim (1) of the utility model registration, wherein the metal ring is formed by molding the peripheral portion of a flat reflecting mirror into a concave or convex shape.