JPS61210701A - Waveguide device - Google Patents

Abstract

PURPOSE:To form a low loss waveguide transmission line which can transmit the high quality microwave signal by providing other wave guide at the side surface of one waveguide and providing a linking hole of suitable shape dimensions between both guides. CONSTITUTION:A main waveguide 2 has the same cross section shape as the transmission line and inserted on the way from the transmission line. At the side surface parallel to the electric field direction 1 of a basic mode (TE11 mode) of the main waveguide, a sub-waveguide 3 is provided through plural linking holes 5. The cross section shape of the sub-waveguide 3 has the dimensions so that the guide wavelength of a TE10 mode of the sub-waveguide 3 can be equal to the guide wavelength of a TM01 mode of the main waveguide 2. For this reason, by selecting so that the number of the linking hole can be optimum, almost all TM01 modes closed in the main waveguide 2 can be induced to the sub-waveguide 3. Further, into the both edges of the sub- waveguide 3, a non-reflecting terminal device 4 is inserted, and the unnecessary TM01 mode can be absorbed.

Description

Detailed Description of the Invention (Industrial Application Field) This invention eliminates unnecessary modes and cross-polarization components that occur in waveguide transmission lines that require low-loss, high-quality microwave communication signal transmission. The present invention relates to a waveguide device for erasing.

(Prior art) Waveguides with low loss and high quality can be used over relatively long distances, such as when connecting the input/output terminals of a microwave antenna and a transmitter/receiver that are installed in a remote location in a microwave transmission system. A transmission line may be required. In general, at the same frequency, the larger the cross-sectional shape of a waveguide, the lower the loss. Therefore, in waveguide transmission lines that require particularly low loss characteristics as described above, the fundamental mode used for the frequency band is usually As for the waveguide, a so-called oversized waveguide with a large cross-sectional shape is used. Then, converters between an oversized waveguide and a fundamental mode waveguide are provided at both ends of the waveguide transmission path, that is, near the input/output ends of the antenna and the transceiver to achieve matching.

(Problem to be solved by the invention) However, since oversized waveguides allow microwave signals in higher order modes to pass in addition to the fundamental mode, discontinuous portions caused by errors in the fabrication of the waveguide, etc. Once higher-order modes and cross-polarization components that often occur due to cross-sectional shape asymmetry, discontinuity of the converter, etc. enter this transmission path, these higher-order modes and cross-polarization components It is not matched by the converter and is reflected and confined within the transmission line.

In this way, the transmission line acts as a type of resonator for higher-order modes and cross-polarized components, which may appear as a resonance phenomenon in the transmission characteristics of the transmission line. This resonance seriously deteriorates the delay characteristics of the transmitted signal, resulting in the disadvantage that high-quality transmission characteristics cannot be obtained. An object of the present invention is to eliminate the above-mentioned drawbacks and provide a low-loss waveguide transmission line that is capable of transmitting high-quality microwave signals.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration.

That is, the high-order mode is connected to the outer periphery of the main waveguide, which has the same cross section as an oversized waveguide through which microwave signals of higher-order modes in addition to the fundamental mode can propagate, through coupling holes with the main waveguide. This is a waveguide device having both or one of a sub-waveguide that couples and absorbs only a mode microwave signal and a sub-waveguide that couples and absorbs only a cross-polarized wave component.

(Function) By installing another waveguide on the side surface of one waveguide, a coupling hole of an appropriate shape and size is provided between the two waveguides. It can be guided into a waveguide. The waveguide device of the present invention has an oversized main waveguide through which high-order mode microwaves can propagate, and a sub-conduit that couples and absorbs only the high-order mode microwaves through coupling holes, and a cross-polarized waveguide. Since both or one of the sub-waveguides that couple and absorb only the components are provided, there is no discontinuity due to manufacturing errors of the waveguide of the waveguide system connected to the waveguide device of the present invention. Higher-order mode electromagnetic waves and cross-polarized components generated by the asymmetry of parts or cross-sectional shapes or the discontinuity of the converter to the fundamental mode waveguide connected to the waveguide device of the present invention are transmitted to the waveguide of the present invention. Even if it enters the tube device, most of it is guided to the sub-waveguide through the coupling hole and absorbed by the absorber and non-reflection terminator provided inside the sub-waveguide. Therefore, higher-order modes and cross-polarization components are caused by mismatching in the converter.
This eliminates the possibility that the light is radiated and confined within the main waveguide, and therefore does not appear as a resonance phenomenon in the transmission characteristics of the transmission path. This resonance phenomenon significantly deteriorates the delay characteristics of the transmitted signal, resulting in a significant deterioration in the quality of the transmission characteristics, but in the waveguide device of the present invention, this resonance phenomenon does not occur, so the quality of the transmission characteristics deteriorates. can be avoided.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a partially sectional structural perspective view of the waveguide device of the present invention. In the figure, the main waveguide 2 has the same cross-sectional shape as the transmission line, and is inserted in the middle of the transmission line. A sub-waveguide 3 is provided on a side surface of the main waveguide parallel to the electric field direction 1 of the fundamental mode (TE mode) via a plurality of coupling holes 5 .

The cross-sectional shape of this sub-waveguide 3 is TE of the sub-waveguide 3, o
D-mode pipe wavelength and main waveguide 2 TM :Mo° 4
``It has dimensions such that some wavelengths within the tube are the same.

Therefore, if the number of coupling holes is optimally selected, the TM,..., is confined within the main waveguide 2. Almost all modes can be guided to the sub waveguide 3.

Furthermore, non-reflection terminations M are provided at both ends of the sub-waveguide 3.

A device 4 is inserted, which can absorb unnecessary TBo+ modes. Also basic mode (TE□,.

Leakage of mode) to the sub-waveguide 3 can be almost ignored by making the coupling hole sufficiently small.

Furthermore, by selecting the spacing between the coupling holes to be 174, which corresponds to the tube wavelength of the TE, 1° mode, the coupling holes do not affect the VSWR characteristics of the main waveguide.

On the other hand, in the figure, on the side surface of the main waveguide 2 perpendicular to the fundamental mode electric field direction 1, there is a slit 7 along the tube axis direction, which has a narrow width and a length that does not change the cross-sectional shape of the circular waveguide. There are several locations. This slit acts as a coupling hole for cross-polarized components. That is, cross-polarized components generated within the transmission path are guided to the sub-waveguide 6 via this slit. Further, the single induced cross-polarized component is absorbed by the radio wave absorber 8 provided on the side facing the slit of the sub waveguide 6. 1. In addition, as mentioned above, the slit is provided perpendicular to the direction of the electric field of the fundamental mode, so in this case as well, the slit is located at the T of the positive polarized wave that is the transmission signal.
E, I. No effect on mode.

The above is a circular waveguide TM. Although we have explained the case of canceling the 1° mode, it is also possible to cancel waveguides with other cross-sectional shapes and other higher-order modes using the same method as above using the appropriate method. Needless to say, it is.

Furthermore, although the above example shows an example in which a high-order mode canceling device and a cross-polarization component canceling device are provided at the same time, it is also effective when one of these is provided as necessary. It can be effective. Furthermore, in the above example, if you want to erase only the TM mode, you can generate it by this device itself by arranging four sub-waveguides 3 having the same shape at 90° intervals around the circular waveguide. The cross-polarization component can be set to a negligibly small value.

(Effects of the Invention) With the configuration and operation described above, the waveguide device of the present invention subtracts unnecessary components such as higher-order mode microwave signals and cross-polarized components that have entered the main waveguide. Since it is guided toward the waveguide and absorbed, it has the advantage that it is possible to avoid quality deterioration of transmission characteristics caused by these unnecessary components.
As a result, this waveguide is used in the middle of a transmission line that uses an oversized waveguide that also transmits high-order mode microwaves because low loss characteristics are particularly required for long-distance transmission. There is an advantage that deterioration of the transmission characteristics of the transmission path can be prevented by inserting the device.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the configuration of an embodiment of the waveguide device of the present invention.・ 7 ・ 3...Sub-waveguide, 4...Reflection-free terminator, 5.
...Coupling hole, 6...Sub waveguide, 7...Slit, 8...Radio wave absorber

Claims (1)

[Claims] In addition to the fundamental mode, microwave signals in higher-order modes are connected to the outer periphery of the main waveguide, which has the same cross section as the oversized waveguide, through which microwave signals in higher-order modes can propagate, through coupling holes with the main waveguide. 1. A waveguide device comprising: a sub-waveguide that couples and absorbs only wave signals; and/or a sub-waveguide that couples and absorbs only cross-polarized components.