JPH11312908A - Waveguide/microstrip line converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveguide/microstrip line converter of an effective structure which enables short circuiting without forming a through hole on a substrate by performing grounding of a cap and a base by way of a substrate outer periphery. SOLUTION: In a waveguide/microstrip line converter in which a substrate 3 provided with a microstrip line 4 so that an antenna prove is positioned toward an opening part of a waveguide 2 is clamped between a cap 6 corresponding to the opening part of the waveguide 2 and a base member 1, it is designed that the cap 6 forms a level difference recessed part 8 with a specific width along two edge of the waveguide 2 on an installation surface for the base member 1 and clamps the substrate 3 between itself and the base member 1 in the state that the edge of the substrate 3 is engaged in the level difference recessed part 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waveguide / microstrip line converter in a feed portion of a planar antenna constituted by a microstrip array antenna having a waveguide interface, and more particularly, to an antenna from a feed circuit by slot coupling. The present invention relates to a waveguide / microstrip line converter applied to an array antenna of a type that feeds elements.

[0002]

2. Description of the Related Art Generally, in a microstrip array antenna having a waveguide interface, in the case of a so-called coplanar feeding antenna in which a feeding line and an antenna element are on the same plane, a waveguide / microstrip line converter is used. , Depending on how the cap and the base are grounded,
The conversion loss did not worsen extremely.

However, in the case of a so-called slot-coupled microstrip antenna in which the antenna element and the feed line are positioned with the ground interposed therebetween and a slot is provided in the ground plate to feed power from the feed line to the antenna element. As described above, in the configuration in which the waveguide / microstrip line converter has the cap and the feed line on the opposite sides with respect to the ground, the degree of grounding of the cap and the base greatly affects the conversion characteristics. come.

[0004]

Therefore, in this case, it is necessary to provide a through hole in the substrate and short-circuit it. However, when the substrate is made of a Teflon sheet or the like, especially when it is thin, It is very difficult to provide a through hole due to processing technology.

The present invention has been made based on the above circumstances, and an object thereof is to ground a cap and a base via the outer periphery of a substrate without forming a through hole in the substrate. Can be shorted,
An object of the present invention is to provide a waveguide / microstrip line converter having an effective structure.

[0006]

Therefore, in the present invention,
A waveguide / micro substrate comprising a substrate having a microstrip line provided so as to position an antenna probe toward an opening of a waveguide between a cap and a base member corresponding to the opening of the waveguide. In the stripline converter, the cap is formed with a stepped recess having a predetermined width along an edge of the waveguide on a mounting surface with respect to the base member, and the edge of the substrate is fitted into the stepped recess. The substrate is sandwiched between the base member and the base member.

Therefore, even when the substrate is made of a very thin material such as a Teflon sheet and it is difficult to provide a through hole, the substrate can be connected to the microstrip line side of the substrate through the step recess. Cap can be shorted. Therefore, the grounding between the cap and the base member is ensured, and good conversion characteristics can be maintained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings. Here, a microstrip line 4 etched on a printed circuit board 3 is placed above a waveguide 2 whose tube axis is perpendicular to the base plate 1.
And the antenna probe 5 at the tip of the antenna probe 5 is disposed in the opening of the waveguide 2.
Is sandwiched between the base member 1 and the cap 6 corresponding to the opening of the waveguide 2.

In such a waveguide / microstrip line converter, according to the present invention, the cap 6 includes the opening of the waveguide 2 and the printed circuit board 3 on the mounting surface with respect to the base member 1 and is parallel to the same. A stepped recess 8 having a predetermined width is formed along the edge of the port 9, and the printed board 3 is held between the stepped recess 8 and the base member 1 in a state where the edge of the printed board 3 is fitted to the stepped recess 8. ing.

In particular, in this embodiment, the cavity 7 of the cap 6 corresponds to the opening of the vertical waveguide 2 opposed thereto, and the depth of the cavity 7 is λ / 4 wavelength of the waveguide 2. This is equivalent to an extension, and at least the above-mentioned stepped concave portion 8 is formed on the periphery thereof. It is preferable that the width of the stepped recess 8 (the portion sandwiching the edge of the printed circuit board 3) be as small as possible. This is to cut off a so-called waveguide mode transmitted in a mode other than the microstrip line and to minimize the conversion loss. In particular, the reason why the width of the stepped concave portion 8 on the peripheral edge of the cavity 7 is reduced is to prevent a higher-order mode of the waveguide 2 from being generated.

Further, the depth of the cavity 7 is set to λ /
As is well known, the cavity 7 is extended by about four wavelengths.
The input radio wave from the waveguide 2 reflected by the bottom surface of the antenna probe is directed to an antenna probe 5 located at a distance therefrom, the electric field is maximized by the antenna probe 5, and the electric field excited by the antenna probe 5 is reduced by a microstrip. This is for transmission by the line 4.

Therefore, even when the printed circuit board 3 is made of a very thin material such as a Teflon sheet and it is difficult to provide a through hole therethrough, the stepped recess 8 can be formed.
, The cap 6 can be short-circuited to the microstrip line 4 side of the printed circuit board 3. For this reason, the grounding of the cap 6 and the base member 1 is reliable, and good conversion characteristics can be maintained.

In the above embodiment, the stepped recess 8
Is provided on the cap 6 side, but this stepped recess 8 is replaced with the cap side or a part thereof is formed on the base member 1.
Of course, it may be formed on the side.

[0014]

According to the present invention, as described in detail above, a substrate provided with a microstrip line so that an antenna probe is positioned toward an opening of a waveguide is provided on the opening of the waveguide. In a waveguide / microstrip line converter sandwiched between a corresponding cap and a base member, the cap has a stepped recess having a predetermined width along an edge of the waveguide on an attachment surface for the base member. The substrate is formed and sandwiched between the base member in a state where the edge of the substrate is fitted in the step recess.

Therefore, even when the substrate is made of a very thin material such as a Teflon sheet and it is difficult to provide a through hole, the substrate can be connected to the microstrip line side of the substrate through the step recess. Cap can be shorted. Therefore, the grounding between the cap and the base member is ensured, and good conversion characteristics can be maintained.

In such a configuration, radiation leakage from the converter is eliminated, the radiation pattern is not affected, and the substrate is sandwiched between the base plate and the cap, so that the characteristics are stable and the substrate is sandwiched. By making the width of the portion as narrow as possible, a so-called waveguide mode transmitted in a mode other than the microstrip line is cut off, and the conversion loss can be minimized.

[Brief description of the drawings]

FIGS. 1A to 1C are a bottom view of a cap, a vertical side view of the entire converter, and a vertical end view, respectively, showing an embodiment of the present invention.

FIG. 2 is also a perspective view of a cap.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base member 2 Waveguide 3 Printed circuit board 4 Microstrip line 5 Antenna probe 6 Cap 7 Cavity 8 Step recess 9 Port

Claims (3)

[Claims] 1. A substrate provided with a microstrip line so as to position an antenna probe toward an opening of a waveguide is sandwiched between a cap corresponding to the opening of the waveguide and a base member. In the waveguide / microstrip line converter, the cap forms a stepped recess having a predetermined width along an edge of the waveguide on a mounting surface with respect to the base member, and attaches the edge of the substrate to the stepped recess. The waveguide / microstrip line converter, wherein the substrate is sandwiched between the base member and the fitted state. 2. The cavity of the cap corresponds to an opening of a vertical waveguide opposed to the cap, the depth of which corresponds to a λ / 4 wavelength extension of the waveguide, 2. The waveguide / microstrip line converter according to claim 1, wherein the stepped concave portion is formed at least on a peripheral edge thereof. 3. The waveguide according to claim 1, wherein the stepped recess is formed instead of the cap side or a part thereof is formed on the base member side.
Microstrip line converter.