JPH04565Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is based on an oversized transmission waveguide installed to transmit microwave and millimeter wave electromagnetic waves between each device and each device. The present invention relates to a waveguide converter used to connect a fundamental mode transmission waveguide of an input/output section of an input/output section.

[Conventional technology]

In microwave and millimeter wave band electromagnetic wave transmission lines, oversized transmission waveguides are used to connect the fundamental mode transmission waveguides of each device to reduce loss. It is often used.

In this case, it is necessary to suppress the occurrence of unnecessary electromagnetic field modes and impedance mismatch as much as possible.

In reality, the oversized transmission waveguide 1 is installed attached to a building or facility, so the oversized transmission waveguide 1 is curved within the side wall of the building, as shown in FIG.

The overall shape and dimensions of the oversized transmission waveguide 1 are determined in advance by the scale and structure of the entire system of the device, and the loss of the oversized transmission waveguide 1 due to such curved points etc. It is, so to speak, determined as a system-specific value.

For this reason, it is necessary that the shape of the tapered waveguide 2 at the connecting portion between the oversized transmission waveguide 1 and the fundamental mode transmission waveguide 3 of each device 6 has as little loss as possible.

As an example, an oversized transmission waveguide with a major axis of 22.9 mm and a minor axis of 12.7 mm and a fundamental mode transmission waveguide with a major axis of 2.032 mm and a minor axis of 1.016 mm are connected by a tapered waveguide with a length of 180 mm. Measurements were carried out as shown in FIG. It can be seen that when two tapered waveguides are connected on the large diameter side, significant ripple loss appears when microwaves around 136 GHz are transmitted.

[Problem that the invention attempts to solve]

However, manufacturing a long, uniformly tapered tube is expensive.

The present invention aims to solve this drawback and provide a waveguide transducer that is easy to manufacture and install.

[Means for solving problems]

The present invention provides a waveguide converter that connects an oversized transmission waveguide and a fundamental mode transmission waveguide having a smaller diameter than this waveguide, in which the diameter of one end is equal to that of the oversized transmission waveguide, A tapered waveguide whose other end has the same diameter as the fundamental mode transmission waveguide, and a linear waveguide with the same diameter as the oversized transmission waveguide and whose length is approximately 900 times longer than the transmission wavelength. are connected in series.

[Effect]

The conversion section of the waveguide does not asymptotically reduce or expand the change in diameter at both ends, but instead consists of a straight cylindrical waveguide with the same diameter as the oversized transmission waveguide and a short tapered waveguide. By combining tubes in series, the transmission characteristics of electromagnetic waves are improved.

This is because when a straight oversized waveguide with a wavelength of approximately 900 times or more than the transmission wavelength is connected, the amount of unnecessary electromagnetic field mode conversion caused by the tapered waveguide is reduced, and resonance due to unnecessary electromagnetic field modes in the transmission path is reduced. This is because it will be removed.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an embodiment of the present invention, in which one end of a linear oversized conversion waveguide 4 of the same diameter is connected to an oversized transmission waveguide 1 laid on a side wall 5. A waveguide converter is shown in which a tapered waveguide 2 that converts the diameter of the waveguide 4 to the diameter of the fundamental mode transmission waveguide 3 is connected.

The feature of this invention is that instead of using a long tapered waveguide that shrinks asymptotically, the connecting and converting part of the waveguide is made of a straight line with a length that is approximately 900 times longer than the transmission wavelength. oversized waveguide transducer and
The reason is that it is used in series with a tapered waveguide.

In this example, two oversized conversion waveguides 4 (rectangular waveguides with a major axis of 22.9 mm, a minor axis of 12.7 mm, and a length of 2 m) are directly connected, and fundamental mode transmission waveguides 3 (major axis of 2.032 mm, rectangular waveguide with a short diameter of 1.016 mm) and transmit electromagnetic waves to it,
The amplitude frequency characteristic diagram shown in FIG. 2 is obtained.

Comparing FIG. 2 with the amplitude frequency characteristic diagram of FIG. 5 according to the conventional embodiment, it can be seen that the amplitude frequency characteristic according to the present embodiment is good, that is, the ripple is small.

This is because the oversize conversion waveguide itself has low loss, and by connecting a long straight oversize waveguide, the amount of unnecessary electromagnetic field mode conversion caused by the tapered waveguide is reduced, and the transmission line This is thought to be because resonance due to unnecessary electromagnetic field modes is reduced.

Figure 3 is an example of a characteristic diagram showing the relationship between the length L of the linear oversized conversion waveguide 4 and the amount of ripple; in this case, the amount of ripple is halved by the linear oversized The length of conversion waveguide 4 is 60cm
This is 3.3 times the length of the tapered waveguide 2. This ripple amount is determined by the length of the tapered waveguide 2, the length of the oversize conversion waveguide 4, and the length of the fundamental mode transmission waveguide 3.
This varies depending on the aperture ratio of the oversized transmission waveguide 1 and the shape of each waveguide.

[Effect of idea]

As described above, according to the present invention, an oversized transmission waveguide and a fundamental mode can be converted by a waveguide converter using a linear oversized conversion waveguide and a short tapered waveguide that is easy to manufacture. Transmission waveguides can be connected without deteriorating amplitude frequency characteristics. This tapered waveguide is easy to manufacture and inexpensive, so it has the effect of realizing a practical waveguide converter.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a waveguide converter according to an embodiment of the present invention. FIG. 2 is an amplitude frequency characteristic diagram of the above embodiment. FIG. 3 is a characteristic diagram of the linear oversized conversion waveguide and ripple amount according to the above embodiment. FIG. 4 is a sectional view of a conventional structure. Figure 5 shows the amplitude frequency characteristics of a conventional short tapered waveguide. DESCRIPTION OF SYMBOLS 1... Oversized transmission waveguide, 2... Tapered waveguide, 3... Fundamental mode transmission waveguide, 4... Linear oversized conversion waveguide, 5... Side wall, 6...
...individual equipment.

Claims (1)

[Claims for Utility Model Registration] In a waveguide converter that connects an oversized transmission waveguide and a fundamental mode transmission waveguide having a smaller diameter than this waveguide, the diameter of one end is the oversized transmission waveguide. A tapered waveguide with the diameter of the other end equal to that of the fundamental mode transmission waveguide, and a straight waveguide with the same diameter as the oversized transmission waveguide with a length approximately 900 times longer than the transmission wavelength. A waveguide converter characterized in that a waveguide is connected in series.