JPH024163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to improvement of the reflection characteristics of a waveguide type non-reflection terminator used in microwave and millimeter waves.

[Prior art]

A waveguide-type non-reflection terminator absorbs electromagnetic waves propagating within a waveguide without reflection, and is often used as a component for three-dimensional circuits.

Figures 1 and 2 show non-reflection terminators conventionally used for rectangular waveguides; the former is a tapered non-reflection terminator 1, and the latter is a multi-stage non-reflection terminator 2.
It is a perspective view showing an example.

These non-reflection terminators are generally manufactured by mechanically processing a block of solid electromagnetic wave absorbing material into the desired shape and dimensions, and there are various shapes. However, although there are various shapes, these non-reflection terminators mainly have a terminator uniform part 3 for absorbing electromagnetic waves and a terminator matching part for impedance matching, as shown in Figures 1 and 2. It basically consists of Section 4.

The tapered non-reflection terminator 1 can obtain relatively broadband electrical characteristics by making the axial length of the terminator matching section 4 approximately one wavelength or more. Further, although the multi-stage non-reflection terminator 2 has a relatively narrow band electrical characteristic, the axial length of the terminator matching section 4 can be shortened to about one quarter of the pipe wavelength at the shortest. The choice between the two is determined by the required conditions, but in either case there are drawbacks as shown below.

First, the shape of the terminator matching portion 4 of the tapered non-reflective terminator 1 is electrically required to have a sharp tip, which has the drawback that processing that satisfies this requirement is difficult. Another drawback was that the tapered tip was easily damaged during handling and storage after processing.

Next, the length of the four axes of the terminator matching part of the multi-stage non-reflection terminator 2 has a large effect on the matching frequency, so it is important to note that the lengths of the four axes of the terminator matching section of the multi-stage non-reflection terminator 2 have a large effect on the matching frequency, so it is strongly affected by processing errors, especially at frequencies with short wavelengths such as the millimeter wave band. However, since the magnitude of the effect of the discontinuous portion varies depending on the material used, it is difficult to match the frequency band.

[Summary of the invention]

This invention was made with the aim of improving such drawbacks, and includes a multi-stage non-reflective type that uses screws in the terminator matching part to configure a matching part having two or more stages, and that allows the matching frequency to be easily adjusted. We propose a terminator.

[Embodiments of the invention]

FIG. 3 shows an embodiment of this invention.
In the figure, 5 is a screw, and 6 is an alignment plate. Since the screw 5 and the terminator uniform portion 3 are connected by a screw structure, the axial length of the protruding portion of the screw 5 can be easily adjusted.
The screw 5 is used in combination with the matching plate 6 to form a two-stage matching section having two impedance compensation sections. That is, the purpose is to cancel the reflected waves mainly generated at the tips of the matching plate 6, the screw 5, and the uniform portion 3 of the terminator in the frequency band used, and the material of the screw 5, the configuration of the matching portion, etc. are adjusted to satisfy this requirement. This is to establish the following.

First, the material of the screw 5 can be any metal, dielectric, radio wave absorbing material, or the like. That is, in the case where the screw 5 is made of metal, reflection becomes a serious problem if the matching section formed by using the screw 5 in combination has a low frequency band in the operating frequency band. Therefore, in this case, a dielectric or a radio wave absorbing material is used as the material for the screw instead of metal.

Next, other embodiments of the configuration of the matching section as shown in FIGS. 4 to 6 can also be considered. In FIG. 4, the width of the matching plate 6 in FIG. 3 is equal to the width of the waveguide, whereas the height of the matching plate 6 is equal to the height of the waveguide. In FIG. 5, two matching plates 6 are used instead of the one shown in FIG.
In addition, the positions of the tips of the two alignment plates 6 are aligned in the tube axis direction. In FIG. 6, the positions of the tips of the matching plates 6 shown in FIG. 4 are different from each other by about a quarter wavelength. The matching section of the terminator shown in FIGS. 3 to 5 is composed of two stages, but the matching section of the terminator shown in FIG. 6 is composed of three stages in order to further widen the band.

When the impedance matching of the terminator is achieved in this way, the uniform portion 3 of the terminator sufficiently absorbs the radio waves, so that the non-reflection terminator according to the present invention has good characteristics similar to the conventional non-reflection terminator. Can be done.

In the above embodiment, the number of stages of the matching section is up to three, but the number of stages is not limited to this. The screws may have different diameters to form a double screw or the like, and the screw portions may form a plurality of stages of matching portions. Although the shape of the tip of the alignment plate is shown as a rectangle, the shape is not limited to this.

Furthermore, it may be applied to other waveguides such as circular waveguides, elliptical waveguides, and cocoon-shaped waveguides.

〔Effect of the invention〕

As explained above, this invention has the effect that by using a screw in the impedance matching part of a non-reflection terminator, fluctuations in the center frequency caused by processing errors can be easily corrected by adjusting the axial length of the protruding part of the screw. be.

[Brief explanation of drawings]

Figures 1 and 2 are perspective views of a conventional tapered non-reflective terminator and a multi-stage non-reflective terminator, respectively;
FIG. 3 is a perspective view of a multi-stage non-reflective terminator showing one embodiment of the present invention, and FIGS. 4 to 6 are perspective views of multi-stage non-reflective terminators showing other embodiments of the present invention. In the figure, 1 is a tapered non-reflective terminator, 2 is a multistage non-reflective terminator, 3 is a terminator uniform part, 4 is a terminator matching part, 5 is a screw, and 6 is an alignment plate. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Using a radio wave absorbing material that fills the entire cross section of the waveguide, a radio wave absorbing plate and a screw are connected in parallel to the end of the radio wave absorbing material along the tube axis direction, and the end of the radio wave absorbing material A multi-stage non-reflection terminator for a waveguide, characterized in that the screw is made to protrude by about a quarter wavelength in the tube axis direction.