JPS58170201A - Waveguide circuit element - Google Patents

Abstract

PURPOSE:To attain the connection of different polarized waves, by inserting a metallic plate having slits symmetrical over respective polarized waves on bonding surfaces of two rectangular waveguides and using the slot mode propagation oscillated in response to the wavelength of electromagnetic waves propagated on the slits. CONSTITUTION:A thin metallic plate having Z-shaped, step-shaped and key- shaped slits is provided between two waveguides 11 and 12 in place of a metallic plate 13. In each slit, lateral and longitudinal total length of the slits are equal and they are proportional to the propagated wavelength. The slits are produced on a copper plate having 50mum thickness with the etching method. In the operation, each slot is used as the slot coupling to enclose the electromagnetic energy resonated in the slits, and the electromagnetic waves are converted into polarized waves having the phase by 90 deg., by using the resonance energy as interposition.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to the structure of a waveguide orthogonal section for microwave and millimeter wave bands.

(b) Background of the Technology Medium-sized waveguides have good attenuation loss for the propagation of electromagnetic waves in the microwave band, and among them, rectangular waveguides with a rectangular cross section are most often put into practical use. Generally, a 1:2 rectangular cross section is standard. Furthermore, the cutoff frequency that can be propagated is determined by this rectangular size. For this reason, as the frequency moves to a higher region, the rectangular cross section of the waveguide is also becoming smaller. In practical structures using waveguides, the rectangular direction cannot be fixed, and in some cases a torsion waveguide (
twlst) is used. However, if the transmission direction is suddenly changed, reflected waves are generated, and due to processing limitations, the length of the twisted portion must be at least twice the wavelength.

(c) Conventional technology and problems FIG. 1 is a perspective view of a conventional torsion waveguide.

The figure shows a case where a rectangular cross section is twisted by 90 degrees. Note that the structural parts are omitted when attaching both ends. Twisted waveguides are processed by filling a rectangular tube with filler, softening it by heating, and twisting it, or by using complicated handicraft processing techniques such as electroforming, which requires skill and is expensive. .

Moreover, it occupies space and becomes a constraint from a design standpoint.

The lengths A and B of the sides of the rectangular dimension of the torsion waveguide are limited by the wavelength as well as the torsion length.

As a means of solving this problem, a waveguide transmission element was invented in which two waveguides with polarization planes different by 90° are joined at their connecting surfaces with an extremely thin metal (patent application 5°2 -1151
06).

FIG. 2 is an exploded perspective view of a conventional waveguide transmission element. Rectangular hole 11 of waveguide 11! , the direction thereof differs from the rectangular hole 12a of the waveguide 12 by 90°. An extremely thin metal plate 13 is interposed between these two waveguides 11 and 12, and this metal plate 13 has two opposing rectangular holes 11M and 1
An L-shaped conductor portion taa is formed at the overlapping portion of 28.

In reality, the waveguide 11, metal plate 13, and waveguide 12 are integrally coupled in the directions of arrows A and B.

FIG. 3 is an enlarged view of an L-shaped conductor portion of a metal plate of a conventional waveguide transmission element. A rectangle 14 indicated by a two-dot chain line is a waveguide 1
The rectangle 15 represents the rectangular hole 11a of the waveguide 12, and the side B of the square 16 where the two rectangles overlap
On the other hand, the two sides C of the center line of the L shape shown by the dashed line are C-
The relationship is 1/2B. This L-shaped ring is a waveguide 11.
12, the side perpendicular to the magnetic field exhibits magnetic inductivity, and the side perpendicular to the electric field exhibits electrical capacitance. Therefore, the L-shaped conductor as a whole corresponds to a low frequency LC resonant circuit. Since the waveguide 11 and the waveguide 12 have completely opposite relationships, the L-shaped conductor is interposed and the polarization direction of the electromagnetic field is 90°.
° Converted. That is, induction and capacitance conversion using an L-shaped conductor.

The invention described above has made it possible to convert the polarization direction with a simple structure instead of using a twisted waveguide.

(d) Purpose of the Invention The present invention further improves the efficiency and degree of freedom of the above-mentioned coupling method. A metal plate having a symmetrical slit is interposed between the slits, and propagation occurs even in connections with different polarizations by utilizing slot mode propagation that resonates according to the wavelength of electromagnetic waves transmitted through the slits. The above object is achieved by a waveguide circuit element.

(f) Embodiment of the Invention FIG. 4 is a plan view of a slit portion for slit mode coupling of a waveguide according to the present invention, in which the left side is a metal plate and the right side is an enlarged view of the slit. (A) Figure shows a two-figure shape, (B) Figure shows a staircase shape, and (C) Figure shows a key shape.

The common point in all three figures is that the total length of the slit in the horizontal direction is equal to the total length E of the slit in the vertical direction. There is a constant proportional relationship with the wavelength being propagated. The slits were formed by etching a copper plate with a thickness of 50 μm.

In the present invention, the slit is connected to a slot connecting table (sl
The resonant electromagnetic energy is confined within the slit, and this resonant energy is used as an intervening device to convert it into polarized waves with a 90° phase. That is, in all three figures, the slits are equal in both the vertical and horizontal directions, and the total length is 2D or 2E.

The principle of the present invention is a method of forming an excitation state of an electromagnetic field in the space of a slit portion in correspondence with the length and wavelength of the slit, and is a well-known principle applied to slot antennas. In this state, a symmetrical electromagnetic field is formed as a mirror surface, as if the slit itself were a virtual transmitter. In the present invention, the phase is 90° because the slit spans two orthogonal sides.
Even if it differs, it will be propagated.

The shape of the slit is not limited to the shape shown in FIG. 4, and the same effect can be expected with any slit configured symmetrically north on two orthogonal sides. Further, as the metal plate, a copper plate is generally used, but there are no particular restrictions, and the thickness should be selected depending on the characteristics and processing method.

(g) Effect of the invention According to the present invention, the conventional invention (Japanese Patent Application No. 52-115106
), it has a smaller and simpler structure than a twisted waveguide, and can be used for more efficient polarization direction conversion.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional torsion waveguide, Figure 2 is an exploded perspective view of a conventional waveguide transmission element, and Figure 3 is an L-shaped metal plate of a conventional waveguide transmission element. An enlarged view of the conductor part of
FIG. 4 is a plan view of the slit portion of the slit mode coupling of the waveguide according to the present invention. In the figure, 11.12 is a waveguide, and 23.33.43 is a metal plate. Figure 3

Claims (1)

[Claims] A metal plate having a slit symmetrically spanning each polarization is interposed between the joint surfaces of two rectangular waveguides where the polarization of the electromagnetic waves to be transmitted is concerned, and the slit is used for transmission. 1. A waveguide circuit element characterized in that the waveguide circuit element propagates even in connections where polarization occurs by utilizing slot mode propagation that resonates according to the wavelength of electromagnetic waves.