JPS6367003A - Double mode horn - Google Patents

Abstract

PURPOSE:To obtain a double mode horn having a frequency characteristic of a wide band by constituting the double mode horn by varying the inside diameter of its phase adjusting part to a tapered shaped. CONSTITUTION:A tapered circular waveguide having such an angle as the inside diameter is varied from D1 to D2 is used as a phase adjusting part 2 of a double mode horn. By varying the inside diameter of the phase adjusting part 2, a variation of the inside diameter extending from a neck part of the horn to its opening becomes stepwise, therefore, a double mode horn having a good characteristic extending over a wide band can be obtained. In addition, a flare type of two stages or that of the more number of stages is also available. Also, a double mode horn which has been combined with other various constitutions such as a flare iris type having an iris in the phase adjusting part 2, or a dielectric loading flare type having a dielectric ring, etc., also has the same effect.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multimode horn used as a primary radiator of an antenna device.

[Conventional technology]

A typical example of a multi-mode horn generally has a configuration as shown in Fig. 6, in which (1) is a horn section, (2) is a phase adjustment section, and (2) is a phase adjustment section.
3) is a flare portion, (4) is a connecting circular waveguide, and (5) is a center line of these.

Next, the operation will be explained. Such a multimode horn is used as a primary radiator of an antenna device. In FIG. 6, T'E, ?, which is the fundamental mode of the circular waveguide as shown in FIG. When a mode is excited, higher-order modes are generated due to changes in the inner diameter of the circular waveguide at two locations: between the flare section (3) and the phase adjustment section (2), and between the phase adjustment section (2) and the horn section (1). For example, Th4 as shown in FIG. mode occurs. Here, the inner diameter (■) of the phase adjustment section (2). Also, select the length Lol and the flare angle α0 of the flare part,
By setting the amplitude and phase of the higher-order mode at the aperture to desired values, the radiation characteristics of the antenna can be adjusted to an 8-plane pattern and an H
An ideal primary radiator with matching surface patterns can be obtained.

[Problem that the invention seeks to solve]

The conventional multi-mode horn is configured as described above.
The phase adjustment part (2) has an inner diameter D. These multi-mode horns have problems such as a limit to their ability to have broadband frequency characteristics.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a multimode horn having broadband frequency characteristics.

[Means for solving problems]

The multi-mode horn according to the present invention is constructed by changing the inner diameter of the phase adjustment section (2) into a tapered shape.

[Effect]

In the multi-mode horn of the present invention, wide-band frequency characteristics are achieved by providing a phase adjustment section in which the inner diameter of the tapered circular waveguide changes.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, (1) is a horn section, (2) is a phase adjustment section,
(3) is the flare part, and (4) is the connecting circular waveguide (
5) is their center line.

As shown in FIG. 1, the multi-mode horn according to the present invention has the following features:
A tapered circular waveguide whose inner diameter is tapered and has an angle δ that changes from D2 to D2 is used as the phase adjustment section (2). For example, in order to obtain a multi-mode horn equivalent to the conventional multi-mode horn shown in Fig. 6 at a certain frequency, in Fig. The output inner diameter D2 of the phase adjustment section (2) determined from (1) is selected so that the amount of generation is made equal to the amount of generation in the conventional multi-mode horn shown in FIG.

Furthermore, the phase amount of the higher-order mode between the phase adjustment section L1 is
In order to make it equal to the phase amount in the conventional multi-mode horn shown in the figure,
The phase adjustment unit (
2) Select the length.

(Here, λ is the wavelength χ is the characteristic constant of the higher-order mode, and ■
! In the case of 1 mode, it is 8.88z) Also, from the length Ll and the angle δ, the input inner diameter D□ of the phase adjustment section (2) is D1=
D2-ZL1tenδ (3) Finally, the amount of higher-order modes generated at the connection between the flare section (3) and the phase adjustment section (2) is determined by the amount of generation of higher-order modes in the conventional multi-mode horn shown in Fig. 6. The angle α1 of the flare portion is determined to be equal to the amount of light α1−light α0+δ (4). By changing the inner diameter of the phase adjustment part (2) in this way, the inner diameter changes gradually from the throat of the horn to the opening as shown in equations (1) to (4). You can get the horn.

Next, other embodiments will be described. The same reference numerals as in FIG. 1 indicate the same or corresponding parts.

Although Fig. 1 shows the case of a single-stage flare type multi-mode horn, as shown in Fig. 2, a two-stage flare type or more stages has the same effect; I don't care. In addition, as shown in FIGS. 8 and 4, various other configurations such as a flare iris type having an iris (6) in the phase adjustment section (2) or a dielectric loaded flare type having a dielectric ring (7) are available. A similar effect is obtained for a multi-mode horn in combination with Further, the same effect can be obtained even when the change in the inner diameter of the phase adjustment portion (2) is not constant with the angle δ but is changed according to a certain function as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, a multi-mode horn having a wide band frequency characteristic can be obtained by providing a phase adjusting section whose inner diameter changes and configuring the change in the inner diameter in stages.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a multi-mode horn according to an embodiment of the present invention, and FIGS. 2, 8, 4, and 5 are external views of multi-mode horns showing other embodiments of the present invention. Figure 6 shows the external appearance of a conventional multi-mode horn. t
Soreso t'L Circular waveguide tl TEo' This is the electromagnetic field distribution of TM+r mode. (1) is a horn part, (2) is a phase adjustment part, (3) is a flare part, and (4) is a connecting circular waveguide. (5) is their center line, (6) is the iris, (
7) is a dielectric ring. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) A multi-mode horn composed of a horn section, a flare section, and a phase adjustment section, characterized in that the phase adjustment section has a configuration in which the shape of the phase adjustment section changes in a tapered shape. (2) The multi-mode horn according to claim 1, characterized in that it is constituted by a circular waveguide. (3) The multi-mode horn according to claim 1, characterized in that it is constituted by a rectangular waveguide.