JPH0198302A - Reflection type rectangular waveguide line - Google Patents

Abstract

PURPOSE:To effectively radiate feeding power by devising the feeding such that it is fed from a horn type waveguide into a rectangular waveguide space via a reflecting face so as to obtain a desired equi-potential face in the rectangular waveguide space. CONSTITUTION:A couple of metallic plates 1, 2 are arranged in the rectangular waveguide line so as to be opposed to each other at a mutual interval and plural slots 1a are formed linearly to one metallic plate 1 as a power radiation aperture. Then the metallic plates 1, 2 are connected by a metal-made side wall 3 except the feeding aperture and the rectangular waveguide space S is formed in the inside by the metallic plates 1, 2 and the metal-made side wall 3. Moreover, a reflecting face C while leaving a gap D is arranged so as to bypass a radio wave propagated through the feeding horn waveguide space A into the space S. Since the cross section shape of the reflecting face C is semi-circular, the reverse traveling of the radio wave due to the reflection on the reflecting face C is prevented sufficiently and effective feeding is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reflective rectangular waveguide line suitable for use as a communication antenna, broadcasting antenna, etc.

[Conventional technology]

FIG. 11 is a central vertical perspective view of a conventional coaxial circular waveguide, and FIG. 12 is an explanatory diagram of radio wave propagation in a cylindrical coordinate system of the coaxial circular waveguide.

Conventional waveguides include circular waveguides such as coaxial type as shown in Fig. 11, and the feeding power within the waveguide space of the circular waveguide is expressed in cylindrical coordinates as shown in Fig. 12. This is the modified TEM coaxial mode expressed by . Therefore, since the feeding power spreads concentrically around the central feeding opening, the power radiation slots are formed concentrically or spirally.

[Problem that the invention seeks to solve]

By the way, although the conventional circular waveguide as described above is suitable as a circularly polarized wave antenna, when radiating a linearly polarized wave, the relative side lobe becomes large when radiating a circularly polarized wave, and the gain is low. There are problems such as a decrease in

The present invention attempts to solve these problems by making it possible to radiate not only circularly polarized waves but also linearly polarized waves with high efficiency, and to improve the equality of the electric field within the rectangular waveguide space. The purpose of this invention is to provide a reflective rectangular waveguide line with phase front compensation.

[Means for solving problems]

Therefore, the reflective rectangular waveguide line of the present invention includes a rectangular waveguide space surrounded by a metal plate, at least one power feeding opening formed in the rectangular waveguide space, and a power feeding opening formed in the rectangular waveguide space. a horn-shaped waveguide for feeding power connected to the opening for power supply, and the feeding power is reflected to the feeding path from the horn-shaped waveguide to the inside of the rectangular waveguide space. It is characterized by the interposition of a reflective surface that can adjust the equiphase front of the electric field.

[For production]

In the above-described reflective rectangular waveguide line of the present invention, when power is supplied from the horn waveguide to the rectangular waveguide space through the power supply opening, the equal phase front is compensated by the reflective surface, and the power is Power that is approximately in phase is radiated through the radiation slot.

〔Example〕

Hereinafter, the reflective rectangular waveguide line of the present invention will be explained with reference to the drawings. Figs. 1 to 7 show a reflective rectangular waveguide line as an embodiment of the present invention, and Fig. 1(a) 1(b) is a perspective view of the central longitudinal section, FIG. 2 is an explanatory diagram of radio wave propagation in the horn-shaped waveguide section, and FIG. 3 is an explanatory diagram of radio wave propagation in the orthogonal coordinate system. , FIGS. 4 to 7 are plan views showing the method of forming the power radiation slot, and FIG. 8 is a plan view showing the method of forming the power radiation slot, and FIG. FIG. 9 is an explanatory diagram of radio wave propagation in an orthogonal coordinate system showing a reflective rectangular waveguide line as a third embodiment of the present invention, and FIG. 10 is an explanatory diagram of radio wave propagation in each of the above embodiments. It is a partial vertical cross-sectional view of a reflective rectangular waveguide line showing a reflective surface C, and the upward reference numerals in each figure indicate substantially the same parts.

First, a first embodiment of the present invention will be described. FIG. 1 is a perspective view of a reflective rectangular waveguide line of the present invention, in which a pair of metal plates 1.2 are spaced apart from each other and face each other. One metal plate l has a plurality of slots (or slots) la formed in a straight line as openings for power radiation. As a result, the metal plate 1 has a power radiation surface.

The metal plate 1.2 has a metal side wall 3 except for the power supply opening.
These metal plates 1.2 and metal side walls 3
A rectangular waveguide space S is formed inside the waveguide.

In addition, a gap is left so that the radio waves propagated through the feeding horn-shaped waveguide space A can be detoured to the rectangular waveguide space S.
is installed.

Since the reflective surface C has a semicircular cross-sectional shape,
It is possible to sufficiently prevent the radio waves from going backwards due to reflection on the reflecting surface C, and power can be supplied effectively.

In addition, the equiphase front of the electric field in the radio wave propagating through the horn-shaped waveguide space A and approaching the reflecting surface C is distributed in an almost cylindrical shape (dotted line) centered on the virtual feeding point 0 as shown in Fig. 2. However, a phase difference occurs in the electric field.

However, the reflecting surface C in this embodiment is formed to be curved in a parabolic shape, and the appearance of the radio waves as seen from the two directions of the orthogonal coordinate system shown in FIG. 3(a) is as shown in FIG. 3(b). x
This is almost equivalent to reflection by a parabola on the y-plane, and the path length of the radio wave in each direction from the virtual feeding point 0 to the parabola and reaching the X-axis is equal. Furthermore, since the path lengths of the radio waves in each direction from the first reflection to the second reflection shown in FIG. The equiphase surface becomes a plane.

Therefore, the slots la can be arranged on a straight line so that the phase matches the plane wave, and the supplied power can be used effectively.

Note that this reflecting surface C is constituted by a surface obtained by translating a parabola on a semicircle, without using a part of a paraboloid of revolution as used in a parabolic antenna or a horn reflector antenna. Additionally, while a parabolic antenna makes the equiphase plane of the TEM wave plane in space, in this embodiment, as mentioned above, the equiphase plane of the electric field of the TE wave inside the rectangular waveguide space is made a plane. The difference is that a horn reflector antenna turns a spherical wave into a plane wave with one reflection, whereas an isotropic waveguide turns a cylindrical wave whose electric field has a cylindrical equiphase plane into a plane with two reflections. The difference is that.

Furthermore, a terminating resistor 5 is disposed at the waveguide terminal end of the reflective rectangular waveguide line in FIG.
The surplus power reaching the end of the waveguide is consumed.

Further, an example of the method of forming the slot 1a in this embodiment is shown in FIGS. 4 to 7. In the forming method shown in FIGS. 5 to 7, the slots la are not parallel to the equiphase plane of the electric field, but are shaped like a T shape tilted by 45 degrees, or a dogleg shape. By using these various methods of forming the slots 1a, the slot density can be increased, the aperture efficiency can be improved, and the polarization characteristics of the reflective rectangular waveguide line of the present invention as an antenna can also be changed. It is possible.

For example, if slots 1a are formed as shown in FIG. 4.6.7, linearly polarized waves can be emitted, and if slots 1a are formed as shown in FIG. 5, circularly polarized waves can be emitted. In addition, in FIG. 6, linearly polarized waves are generated in the four slots la-sets enclosed in the figure, and these are arranged vertically and horizontally. Also, slot l
The length of a is approximately half a wavelength, and the width is smaller than the wavelength.

Next, to explain the second embodiment of the present invention, as shown in FIG.
That is, it is an arc, and the state of the radio wave is equivalent to reflection by an arc on the Xy plane, and the equiphase front of the electric field in the radio wave appearing in the rectangular waveguide space is as shown in FIG. Other effects are the same as in the first embodiment described above.

Next, to explain the third embodiment of the present invention, as shown in FIG. 9, the reflecting surface C has a straight line shape when viewed from two directions, and the appearance of the radio waves is equivalent to reflection by a straight line on the xy plane.
The equiphase front of the electric field in the radio waves appearing in the rectangular waveguide space is as shown in FIG. Other effects are the same as in the first embodiment described above.

Furthermore, in each of the above-described embodiments, the vertical cross-sectional shape of the reflecting surface C on the y2 plane may not be a semicircle but may be a semi-polygon as shown in FIG. 10.

Furthermore, the shape of the horizontal cross section of the reflective surface C may be an ellipse or a hyperbolically curved shape.

〔Effect of the invention〕

As described in detail above, according to the reflective rectangular waveguide line of the present invention, power is fed into the rectangular waveguide space by the horn-shaped waveguide via the reflective surface, so that the rectangular waveguide A desired equiphase surface within the tube space can be obtained by appropriately designing the reflecting surface, and the feeding power can be effectively radiated.

[Brief explanation of the drawing]

1 to 7 show a rectangular waveguide line for reflection as an embodiment of the present invention, and FIG. 1(a) is a perspective view thereof, and FIG.
Figure (b) is a central vertical perspective view of the same, Figure 2 is an explanatory diagram of radio wave propagation in the horn-shaped waveguide section, Figure 3 is an explanatory diagram of radio wave propagation in the orthogonal coordinate system, and Figures 4 to 7. is a plan view showing a method of forming the power radiation slot, and FIG. 8 is an explanatory diagram of radio wave propagation in an orthogonal coordinate system showing a reflective rectangular waveguide line as a second embodiment of the present invention. FIG. 9 is an explanatory diagram of radio wave propagation in an orthogonal coordinate system showing reflection and a rectangular waveguide line as a third embodiment of the present invention;
FIG. 0 is a partial vertical cross-sectional view of a reflective rectangular waveguide line showing the reflective surface C in each of the above embodiments, FIG. 11 is a central vertical cross-sectional perspective view of a conventional coaxial circular waveguide line, and FIG. is an explanatory diagram of radio wave propagation in a cylindrical coordinate system of a coaxial circular waveguide. 1...Metal plate, 1a...Slot for power radiation, 2...Metal plate, 3...Side wall, 4...Horn type waveguide, 5...Terminal resistor, A...Horn type waveguide space , C... reflective surface, D
...Gap, S...Square waveguide space, 0...Virtual feeding point,
λ・Free space wavelength. Agent Patent Attorney Yoshihiko Iinuma (b) Figure 3 D (b) Figure 4 λ Figure 5 ■ Figure 6 Figure 7 Figure 8 Figure 9 y Figure 10

Claims (2)

[Claims] (1) A rectangular waveguide space surrounded by a metal plate, at least one power feeding opening formed in the rectangular waveguide space, and a power feeding horn-shaped waveguide connected to the power feeding opening a reflecting surface capable of adjusting the equiphase front of the electric field in the rectangular waveguide space by reflecting the feeding power to a feeding path from the horn-shaped waveguide to the rectangular waveguide space; A reflection type rectangular waveguide line characterized by having an interposed. (2) a power radiation slot is formed in the metal plate;
A reflective rectangular waveguide line according to claim 1.