JPH03217104A - Ridge waveguide-micro strip line converter - Google Patents

Abstract

PURPOSE:To simplify the structure to facilitate the assembly work by constituting a micro strip line so that its surface is parallel with the front end face of a coupling ridge and faces this front end face with a prescribed gap between them and directly providing a DC cutoff function without restrictions on the form of the periphery of the connection part between a ridge waveguide and the micro strip line. CONSTITUTION:A coupling ridge part 11 projecting inward from a wall of a ridge waveguide 1 parallel with the H face is provided in the front end part of the ridge waveguide 1. A dielectric substrate 2a is fixed to the opposite wall, and a micro strip line 2 is constituted on this substrate 2a, and such space 4 is formed so that the upper face of the micro strip line 2 and the front end face of the coupling ridge part 11 face each other with a gap S between them in parallel with each other. Consequently, the microwave made incident from the side of the ridge waveguide 1 is propagated in the waveguide and is transmitted from the last coupling ridge part 11 to the micro strip line 2 through the space 4. The strength of coupling of the microwave in the space 4 is dependent upon the gap S, thickness (t) of the dielectric substrate 2a, width D of the coupling ridge part 11, length L of the coupling part between them, and width W of the micro strip line 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a ridge waveguide-to-microstrip line converter employed in microwave equipment.

(Prior art) In the microwave band, transmission line conversion from a ridge waveguide to a microstrip line has conventionally been performed using the methods shown in Figs. 6 to 8.
A ridge waveguide-to-microstrip line converter as shown in the figure is used.

That is, the ridge tip 11 of the ridge waveguide l and the microstrip line 2 formed on the dielectric substrate 2a are connected by welding gold foil 3 (welding: a connection work generally performed in the assembly of microwave equipment). and then connected.

When making connections using the gold foil 3, the surfaces on which the gold foil 3 should be welded are at right angles to each other as shown in FIG.
In view of the operability of the equipment that performs welding, the shape of the area around the connection between the ridge waveguide 1 and the microstrip line 2 is often subject to significant restrictions.

In addition, in order to minimize mismatch in the microwave band caused by physical discontinuity at the connection part, it was required to weld the gold foil 3 with high precision within a minute range, which made the work difficult. .

In addition, when an amplifier circuit is configured by connecting an active element such as a field effect transistor 2 to the microstrip line 2, the DC bias to be supplied to the active element is transmitted from the microstrip line through the connection part of the gold foil 3. This may cause a short circuit to the ridge waveguide 1, making it impossible to supply bias.

In order to avoid this, conventionally, a DC blocking capacitor was connected in series with the microstrip line 2, or microstrip coupled lines 21 and 22 having a spacing d and a coupling length L as shown in FIG. 8 were provided. .

However, such a method has the disadvantage that the circuit becomes complicated and the configuration becomes large, and improvements have been desired.

(Problems to be Solved by the Invention) In the conventional ridge waveguide-to-microstrip line converter, since the two were directly connected by a gold foil weld, it was necessary to add a DC blocking circuit, and the use of equipment for welding was required. From above. Assembling work was also troublesome due to restrictions on the shape of the area around the connection.

The present invention eliminates the above-mentioned conventional drawbacks, has a direct current blocking function without being restricted by the shape of the area around the connection between the ridge waveguide and the microstrip line, has a simple structure, and is easy to assemble. It is an object of the present invention to provide a waveguide-microstrip line converter.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a ridge waveguide having a coupling ridge portion protruding inward from a tube wall parallel to the H-plane of the waveguide, and In a ridge waveguide-microstrip line converter comprising a microstrip line formed on a dielectric substrate fixed to a tube wall opposite to the tube wall, the microstrip line surface is located at the tip of the coupling ridge portion. It is characterized by being configured to face each other parallel to the surface with a predetermined gap therebetween.

(Function) The ridge waveguide-microstrip line converter according to the present invention is configured such that the tip end face of the coupling ridge portion and the microstrip line face face each other with a predetermined gap, so that microwaves can be The information is transmitted between the two by electromagnetic coupling using the gap.

Therefore, the conventional weld connection using gold foil is not required, and since the signal is transmitted using the gap, the structure is such that direct current is blocked as is.

(Embodiments) Hereinafter, embodiments of the ridge waveguide-microstrip line converter according to the present invention will be described in detail with reference to FIGS. 1 to 5. Components that are the same as the conventional configuration shown in FIGS. 6 to 8 will be described with the same reference numerals.

That is, FIGS. 1 to 3 show a first embodiment of the ridge waveguide-microstrip line converter according to the present invention. A coupling ridge portion 1l is provided which projects inwardly from the tube wall.

On the other hand, a dielectric substrate 2a is fixed to a tube wall opposite to the tube wall, and a microstrip line 2 is formed on the dielectric substrate 2a. A gap 4 is formed so as to face each other in parallel with a distance S between them.

Therefore, the microwave incident from the ridge waveguide l side propagates within the waveguide and is transmitted from the final coupling ridge portion 11 to the microstrip line 2 via the gap 4.

As shown in FIGS. 2 and 3, the strength of the microwave coupling in the gap 4 is determined by the distance S, the thickness t of the dielectric substrate 2a, the width D of the coupling ridge 11, and the width of the coupling portion between the two. It depends on the length L and the width V of the microstrip line 2.

By the way, since the interval S of the gap 4 is normally required to be minute, high-precision machining is required, but in order to make the fine machining work as easy as possible, the interval S
It is desirable that it be as large as possible.

Therefore, if the length L of the coupling portion where the coupling ridge portion 11 and the microstrip line 2 overlap each other is approximately 174 of the line wavelength of the microstrip line 2 constructed on the dielectric substrate 2a, the coupling strength is is the maximum, so the interval S can be increased under the condition that the degree of coupling is equal.

Further, in this first embodiment, the gap 4 is a space, but
If a dielectric thin film with a length approximately equal to the length of the coupling part is inserted into this gap 4, the transmitted microwave will be transmitted under stronger electromagnetic coupling by the dielectric, and similarly, the distance S will be reduced. It becomes possible to expand further.

4 and 5 show a ridge waveguide-to-microstrip line converter according to a second embodiment of the present invention, in which a dielectric substrate 2a and a ridge waveguide are brought into close contact with each other. Strong electromagnetic coupling can also be obtained between the ridge waveguide 1 and the microstrip line 2 by providing a groove portion 11a having a length approximately equal to the length of the coupling portion between the groove portion 11a and the ground plane of the ridge waveguide 1. be able to.

Therefore, this also makes it possible to increase the distance S with the same degree of bonding, and facilitates the manufacturing process of the bonding ridge portion 1l.

In each of the above embodiments, as shown in FIGS. 1 and 4, the center line of the coupling ridge portion 11 and the center line of the microstrip line 2 are configured to match, but they do not necessarily have to match. There isn't.

In addition, the shape of the ridge part of the ridge waveguide l has a stepped height and is converted from a ridge waveguide to a rectangular waveguide. It may be configured such that the conversion is gradually decreased as follows. Of course,
If conversion to a rectangular waveguide is not required, the conversion section can be omitted.

[Effects of the Invention] As described above, in the ridge waveguide-microstrip line converter according to the present invention, microwaves are transmitted between the coupling ridge portion and the microstrip line by electromagnetic coupling using the gap. Therefore, it can be realized with a simple structure without requiring welding work as in the conventional method.

Further, according to the present invention, direct current is blocked by the gap without providing a capacitor or a special coupling line, so it is suitable for assembling microwave equipment and has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the ridge waveguide-microstrip line converter according to the present invention, FIG. 2 is an enlarged cross-sectional view taken along line X-X of the converter shown in FIG. The figures are a partial sectional view taken along Y-Y line of the converter shown in FIG. 2, FIG. 4 is a sectional view showing a second embodiment of the ridge waveguide-microstrip line converter according to the present invention, and FIG. is a cross-sectional view taken along line X-X of the converter shown in FIG. 4, FIG. 6 is a cross-sectional view of a conventional ridge waveguide-to-microstrip line converter, and FIG. 7 is a cross-sectional view taken along line X-X of the converter shown in FIG. The X-ray cross-sectional view and FIG. 8 are cross-sectional views showing another conventional ridge waveguide-to-microstrip line converter. 1... Ridge waveguide, 1l... Coupling ridge part,
11a...Groove portion, 2...Microstrip line, 2a...Dielectric substrate, 21. 22...Coupled line, 9 3...Gold foil, 4...Gap. 10 one? +C%J (Cl dimension 7- O4

Claims (1)

[Claims] A ridge waveguide having a coupling ridge protruding inward from a tube wall parallel to the H-plane of the waveguide, and the waveguide formed on a dielectric substrate fixed to the opposite tube wall. A ridge waveguide-to-microstrip line converter comprising a microstrip line, wherein the microstrip line surface is configured to face the tip surface of the coupling ridge part in parallel with a predetermined gap. A ridge waveguide-microstrip line converter characterized by: