JPH03213002A - Waveguide-microstrip line converter - Google Patents

Abstract

PURPOSE:To decrease radiation at the connection part of a waveguide and an MSL(microstrip line) by providing the prolonged part of an air coaxial part and the outer conductor of a cover between tips of the inner conductor at the side of the MSL being the connection part and the tip of the MSL to allow the air coaxial part and the MSL to cover the inner conductor. CONSTITUTION:An inner conductor 4A at the side of a waveguide of a coaxial line 3 is inserted in the waveguide 1. Moreover, an air coaxial part 7 whose dielectric part is formed by air is formed on the way of an inner conductor 4B at the side of an MSL(microstrip line) opposite thereto and the tip of the inner conductor 4B of the MSL side and the end of the MSL 2 are connected by a conductive ribbon 6. Furthermore, only an air coaxial part 7 is prolonged by only an air coaxial prolonged part 8 so that the MSL side inner conductor 4B of the air coaxial part 7 is surrounded by said side face in comparison with figure 4 illustrating a conventional example and a conductive cover 9 is fitted to the upper the conductive ribbon 6. The conductor parts of the air coaxial prolonged part 8 and the cover 9 cover the entire direction of the said side face to approach the connection part coming from the MSL side inner conductor 4B to the end of the MSL 2 via the ribbon 6 to a balanced line.

Description

[Detailed Description of the Invention] [Summary] Regarding the structure of a waveguide-microstrip line converter used in the input/output section of equipment such as amplifiers in the microwave and millimeter wave bands, In a device that performs microwave signal conversion via a coaxial line arranged perpendicularly to a waveguide and a microstrip line with the purpose of reducing radiation at the connection part, the inner conductor on the MSL side of the coaxial line In order to create a structure that surrounds the connecting part between one end of the microstrip and one end of the pline, an air coaxial extension part is formed by extending the air coaxial part integrally connected to the coaxial line by a desired length, and the air coaxial extension part Surrounding the side surface and the tip of the MSL side inner conductor with a conductor part,
In addition, a lid is provided in which the distance of the enclosed gap is selected to be a desired length, and the structure is configured such that impedance matching can be obtained at the connection portion.

[Industrial application field]

The present invention relates to the structure of a waveguide-microstrisobrine converter used in the input/output section of equipment such as amplifiers in the microwave and millimeter wave bands.

[Conventional technology]

4 and 5 are diagrams showing an example of the structure of a conventional waveguide-microstrisobrine converter. FIG. 4 shows a cross-sectional view, and FIG. 5 shows a perspective view of the connection part. show. In Figures 4 and 5, 1 is a waveguide, LA is a waveguide short-circuit surface, 2 is a microstrip line (hereinafter referred to as MSL), 3 is a coaxial line, 4 is an inner conductor, and 4A is a waveguide. 4B is the MSL side inner conductor, 5 is the microstrip board that becomes the base of MSL2, 6 is the conductive ribbon, 7 is the coaxial line 3
This is the air coaxial part of.

As shown in Figures 4 and 5, the waveguide converts signals between the waveguide 1, which is a low-loss transmission path in the micro/millimeter wave band, and the MSL 2, which is used in matching circuits such as amplifiers. Some tube-to-microstrisobrine converters have a structure in which signal conversion is performed between the waveguide 1 and the MSL 2 via coaxial lines 3 disposed perpendicularly to the waveguides 1 and MSL 2, respectively.

In this case, the waveguide side inner conductor 4A on one side of the coaxial line 3
is parallel to the electric field direction in the waveguide 1, and the waveguide short-circuit plane I
From A, λg/4 (approximately 1.0 for 50C, Hz millimeter wave)
mm) and air coaxial section 7 on the opposite side.
The tip of the MSL side inner conductor 4B and the end of the MSL 2 are connected by a conductive ribbon 6.

In this case, the direction of the electromagnetic field on the coaxial line 3 is that the electric field is distributed in the radial direction of the coaxial line 30, and the magnetic field is distributed in the circumferential direction. Moreover, on the MSLZ, the electric field takes a distribution perpendicular to the traveling direction. Note that in a converter with this structure, waveguides 1 and M
SL2 is parallel, so if this converter is used in the input/output section of an amplifier, the waveguide 1 in the input/output section will be parallel, and the waveguide 1 and MSL2 will be perpendicular to each other. It is smaller and easier to use than the previously used amplifier. The dimensions of each part are, for example, when the operating frequency is 50 GHz, the 8 dimensions of the waveguide 1 are approximately 2.4 ++ uw, the inner diameter of the air coaxial portion 7 is approximately 0.8 am, and the diameter d of the inner conductor 4 is approximately 0.2
The width of the MSL 2 and the thickness of the MSL substrate 5 are approximately 0.2 am.

The MSL side inner conductors 4B and M of the coaxial line 3 having such a structure
There is a sharp structural discontinuity in the part where SL2 is connected. As mentioned above, the electromagnetic field distribution of the coaxial line 3 and the MSL
The distribution of electromagnetic field distribution of 2 is both inner conductor 4 and MS
It is orthogonal to L2, and there is no matching part in this orthogonal part. Therefore, the matching in the connection part A where the coaxial line 3 and MSL2 are structurally orthogonal, so-called field matching, is not good. Further, the characteristic impedance of the normal MSL 2 is 50Ω, and the characteristic impedance of the coaxial line 3 and the air coaxial portion 7 is also often 50Ω. However, it is difficult to determine the impedance at this connection because the structure is uncertain, and this tends to cause impedance mismatch.

Further examination of the connection between the coaxial line 3 and the MSL 2 reveals that there is a discontinuity in the middle between the coaxial line 3 as the main conductor and the conductive ribbon 6 perpendicular thereto. Further, the external conductor on the opposite side of the MSL board 5 from the MSL 2 is bent at a right angle in the middle and is only on one side. That is, the connecting portion is formed of an unbalanced line having discontinuous portions.

[Problem to be solved by the invention]

Therefore, there is a problem in that characteristic impedance mismatch occurs at discontinuous portions of the line, and a large amount of signal is radiated, resulting in a large proportion of the radiation loss in the loss of the converter.

The present invention aims to reduce radiation at the connection between the waveguide and the MSL.

[Means to solve the problem]

The present invention provides a waveguide 1 and a microstrip line 2.
In a device that performs microwave signal conversion via a coaxial line 3 arranged perpendicular to the MSL of the front distribution axis line 3,
In order to create a structure that surrounds the connecting portion between one end of the side inner conductor 4B and one end of the microstrip line 2, the coaxial line 3 is
an air coaxial extension part 8 obtained by extending the air coaxial part 7 integrally connected to the air coaxial part 7 by a desired length; and the air coaxial extension part 8.
A lid 9 is provided which surrounds the side surface of the MSL side and the tip of the MSL side inner conductor 4B with a conductor part, and the distance between the enclosed gaps is selected to be a desired length, and the structure is configured such that impedance matching can be obtained at the connection part. It is something to do.

[For production]

In the present invention, the structure shown in FIGS. 1 and 2 is used, and the extension part 8 of the air coaxial part 7 and the M9 outer conductor are provided at the tip of the MSL 2 from the tip of the MSL side inner conductor 4B, which is the connection part, to surround it. In this way, the radiation is suppressed, and the field masoching is improved by approaching the balanced line, and the height of the outer conductor on the upper side of the conductive ribbon can be adjusted.

It's built.

Therefore, it is possible to change the impedance of the connection part, and it is possible to easily match the characteristic impedance between the coaxial line 3 and the MSL 2 at the connection part.

〔Example〕

1 and 2 are diagrams showing an example of the structure of the waveguide-microstrisopline converter of the present invention, with FIG. 1 showing a cross-sectional view, and FIG. 2 a perspective view of the connection part. shows. Note that FIG. 3 is a diagram showing an example of the shape of the lid of the present invention. In the figure,
1 to 7 are as in the conventional example shown in FIGS. 4 and 5,
1 is the waveguide, IA is the waveguide short-circuit surface, 2 is MSL, 3 is the coaxial line, 4 is the inner conductor, 4A is the inner conductor on the waveguide side, 4B is M
SL side inner conductor, 5 is MSL forming the heath of MSL2
6 is a conductive ribbon; 7 is an air coaxial portion of the coaxial line 3; Note that 8 to 9 are parts of the present invention, 8 is an air coaxial extension part, and 9 is a lid.

As shown in FIGS. 1 to 3, the waveguide inner conductor 4A of the coaxial line 3 is inserted into the waveguide 1. As shown in FIGS.

Further, an air coaxial part 7 whose dielectric part is made of air is formed in the middle of the MSL side inner conductor 4B on the opposite side, and a conductive ribbon 6 is formed between the tip of the MSL side inner conductor 4B and the end of the MSL 2.
Connect with. Furthermore, compared to the conventional example shown in FIG.
) L, and above the conductive ribbon 6 is a conductive lid 9.
Attach. This air coaxial extension 8 and lid 9 are
The MSL side inner conductor 4B of the connection part is surrounded in all directions on the side surface by the extension part 8 and the conductor of the lid 9, and from this, the MSL side inner conductor 4B
The connection portion from the end of the SL side inner conductor 4B through the ribbon 6 to the end of the MSL 2 approaches the balanced line. Furthermore, as shown in FIGS. 2 and 3, the lower surface of M9 has a protrusion with a cross section that is a combination of a semicircle and a rectangle and has a diameter slightly larger than the diameter of the air coaxial portion 7 (approximately 0.8 mm at 50 GHz). IO, and the height of this protrusion 10 also has a negative value)
By replacing the ribbon with a different one, the gap distance to the lid 9, which is a ground conductor located above the ribbon 6, can be changed. That is, the impedance of the connection part can be adjusted and matched with the characteristic impedance. As a result, the loss of the converter including the connection part was 0.4 dB with the conventional structure, but with the present invention it is 0.3 dB.
dB, resulting in an improvement of approximately 0.1 dB.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, radiation loss and impedance mismatch at the connection portion of the converter can be suppressed, and the loss of the converter can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram (cross-sectional view) showing a structural example of the waveguide-microstrinoline converter of the present invention. FIG. 2 is a diagram showing a structural example of the waveguide-microstrinoline converter of the present invention. (Perspective view of the connection part), Figure 3 is a diagram showing an example of the shape of the lid of the present invention, Figure 4 is a diagram showing an example of the structure of a conventional waveguide-microsin converter, and Figure 5 is a diagram showing an example of the structure of a conventional waveguide-microsin converter. Figure (perspective view) showing an example of the structure of a waveguide-microsin converter. In the figure, 1 is a waveguide, 2 is a microstrip line 3 is a coaxial line, 4 is an inner conductor, 4A is an inner conductor on the waveguide side, 4B is an inner conductor on the MSL side, 7 is an air coaxial part, 8 is an air coaxial line 9 indicates a lid, and 10 indicates a protrusion. (MSL) Trisopra (cross-sectional view), Tripura (1st figure of the connection section) 3rd figure of the Microstri-Nobline imprint, 3rd figure of this ship's skin Tongue - Microstoso 7puui/henbaku (
4 degrees 1 ripe f 1 minute degree 1 (grain bite sound P's bite tilts 2 bars 18 Fig. 5

Claims (1)

[Claims] In a device that performs microwave signal conversion via a coaxial line (3) arranged perpendicularly to a waveguide (1) and a microstrip line (2), the coaxial line (3) In order to create a structure that surrounds the connecting part between one end of the MSL side inner conductor (4B) and one end of the microstrip line (2), an air coaxial part (
Air coaxial extension part (8) that extends 7) by the desired length
and a lid (9) that surrounds the side surface of the air coaxial extension part (8) and the tip of the MSL side inner conductor (4B) with a conductor part, and the distance of the enclosed gap is selected to be a desired length. A waveguide-microstrip line converter, characterized in that the waveguide-microstripline converter has a structure in which impedance matching can be obtained at the connecting portion.