JPH07202524A - Micro strip waveguide conversion circuit - Google Patents

Abstract

PURPOSE:To attain isolation between a waveguide ana the other circuits by perpendicularly arranging the waveguide and a dielectric substrate and terminating the waveguide by a conductor to reduce the leak of a transmission signal. CONSTITUTION:A taper line 4 provided for impedance matching and a ridge part 2 projecting into a waveguide 1 are connected by a gold ribbon 3, and a conversion circuit of a micro strip line 5 and the waveguide 1 is formed. The upper part of the waveguide 1 is terminated by a metallic plate. In the micro strip waveguide conversion circuit having this constitution, a radio wave in the micro wave band is propagated between the micro strip line 5 and the waveguide 1 with a small loss. Since easier wire bonding or gold ribbon than press-fitting, fastening, or the like for conventional connection between the ridge part and the micro strip can be used as the method of construction of a hybrid IC, the circuit is inexpensively formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip waveguide conversion circuit, and more particularly, the present invention relates to a high frequency interface for transfer conversion of a microwave signal between the waveguide and the microstrip, Especially 18GH
The present invention relates to a microstrip waveguide conversion circuit in quasi-millimeter wave and millimeter wave of z or more.

[0002]

2. Description of the Related Art Conventionally, the transfer conversion between a waveguide and a microstrip is generally roughly divided into circuits of the following four types. The first is a type in which a microstrip is converted into a coaxial structure, and the coaxial structure is converted into a waveguide by using an antenna. The second is a type that uses a fin line to convert a microstrip into a waveguide. The third type is a type in which a stripline antenna is formed on a dielectric substrate and this antenna is inserted into a waveguide to convert a microstrip into a waveguide. And the fourth
Is a type that converts a microstrip using a tapered ridge waveguide. In these conversion circuits, the first circuit structure is mainly used in the region of 15 GHz or less, but 18 GHz or more, particularly 30 GHz.
In the above millimeter wave region, the second or third circuit structure is often used, and the fourth ridge waveguide type is particularly often used from the viewpoint of the width of the frequency band and the passage loss.

As shown in FIG. 6, in the conversion between a normal tapered ridge waveguide and the microstrip 62, the ridge waveguide is arranged in parallel with the dielectric substrate 67, and the ridge 6 is formed.
2 and the microstrip 65 are connected by contact. This ridge design method is described in the paper "Straight forward approa
ch produces broadband transitions (Microwaves & RF
page 113-118 Sep, 1984) ". When this conversion is used, the connection characteristics between the ridge and the microstrip are important, and have a great influence on the passage loss and the return loss. To solve this problem
As disclosed in Japanese Patent No. 146004, there is a method for easily contacting the ridge portion. In FIG. 7, the bolt 73 is fastened in parallel with the ridge 72 so that the bolt 73 is arranged without affecting the microstrip waveguide.
5 has a structure that ensures the contact between the ridge portion 72 and the ridge portion 72.

[0004]

However, in the conventional ridge waveguide and the microstrip conversion structure as described above, it is difficult to terminate the end of the waveguide on the microstrip line side, and a signal easily leaks to the outside. become. Further, it is necessary to hermetically seal a hybrid IC mounted with a pair of chips such as FETs, but it is difficult to secure hermeticity in the structure of the conventional microstrip ridge waveguide.

According to the present invention, the microstrip and the waveguide can be easily connected, hermetically sealed, the signal leakage can be reduced, and the isolation between the interface waveguide and other circuits can be achieved. It is an object of the present invention to provide a microstrip waveguide conversion circuit that can be obtained.

[0006]

To achieve the above object, a microstrip waveguide conversion circuit according to the present invention comprises a dielectric substrate having a microstrip line formed therein and a waveguide having a ridge provided on the E surface. A waveguide, the waveguide and the dielectric substrate are arranged substantially vertically, the ridge and the microstrip line are electrically connected, and the waveguide is configured to be terminated by a conductor. I am trying.

[0007]

According to the microstrip waveguide conversion circuit of the present invention, the waveguide and the dielectric substrate are arranged substantially vertically, the ridge and the microstrip line are electrically connected, and the waveguide is electrically conductive. Since it is terminated by the body, the connection between the ridge and the microstrip line is easy, and the termination of the waveguide is shielded.

[0008]

Embodiments of the microstrip waveguide conversion circuit according to the present invention will now be described in detail with reference to the accompanying drawings. 1-5, there is shown an embodiment of the microstrip waveguide conversion circuit of the present invention.

FIGS. 1 and 2 show a first embodiment of a microstrip waveguide conversion circuit of the present invention, and show a form of connection between a microstrip and a waveguide when a hybrid IC is formed. The present embodiment includes a waveguide 1, a ridge 2, a gold ribbon 3, a taper line 4, a microstrip line 5, a metal plate 6 and a dielectric substrate 7.

The function of these components will be described below. The waveguide 1 is a feeder line that propagates a microwave band signal as an electromagnetic wave. The ridge 2 is for impedance matching in order to efficiently transmit radio waves between the microstrip line 5 and the waveguide 1, and is provided on the E surface inside the waveguide 1 in the transmission line direction. Is installed with an inclination. The gold ribbon 3 is a connection line for ensuring electrical continuity between the ridge 2 and the microstrip line 5. The taper line 4 is a portion formed at the end of the microstrip 5 connected to the ridge 2 to improve the propagation characteristics. The microstrip line 5 is a microwave transmission line composed of a single strip conductor, and is fixed to a dielectric substrate 7 having a ground plane on its back surface. The metal plate 6 is a plate having a high conductivity for the purpose of shielding microwaves, and an iron plate is used in this embodiment.

As shown in FIGS. 1 and 2, each component having the above function connects a taper line 4 provided for impedance matching and a ridge portion 2 protruding from the waveguide 1 with a gold ribbon 3. Then, a conversion circuit between the microstrip line 5 and the waveguide 1 is formed. In addition, A- in FIG.
As can be seen from FIG. 2 showing the A ′ cross section, the upper portion of the waveguide 1 is terminated by the metal plate 6.

The microstrip waveguide conversion circuit configured as described above can propagate electromagnetic waves in the microwave band between the microstrip line 5 and the waveguide 1 with low loss. FIG. 3 shows an example of characteristics of the microstrip waveguide conversion circuit having the above-described configuration, and shows the return loss 31 and the passage loss 33 with respect to frequency gain.

Conventionally, the ridge portion of the waveguide and the microstrip have been connected by crimping, tightening, or the like. With the above configuration, however, a simple wire bonding or a gold ribbon can be used as a hybrid IC construction method. Can be used. Further, this method facilitates inexpensive formation of the microstrip waveguide conversion circuit.

FIG. 4 shows a second embodiment. In this embodiment, brazing is used to connect the ridge portion 12 of the waveguide 11 and the microstrip 15. Dielectric substrate 17
A through hole 18 is provided in the ridge portion 12 of the waveguide 11.
And the microstrip 15 are connected by brazing. Other parts may be the same as in the first embodiment.

FIG. 5 shows a third embodiment, which shows an example of a hermetically sealed structure. Although the first and second embodiments do not have an airtight sealing structure, in the present embodiment, the sealing dielectric substrate 19 is formed of the same dielectric material as the dielectric substrate 17 holding the microstrip 15. Then, by covering the entire inner surface of the waveguide 11, an airtight sealing structure is formed.

The structure of FIGS. 6 and 7 of the conventional example cannot prevent the leakage of signals from the waveguide portions 61 and 71, but any of the above-described embodiments can realize the hybrid I.
In the C-structure, the metal plate 6 has an effect of preventing signal leakage. This characteristic enables a gradual decrease in the amount of leakage to other circuits when the waveguide section is terminated on the installation surface of the hybrid IC, particularly in the waveguide structure for both input and output. The shielding can reduce microwave leakage and prevent adverse effects on a circuit portion such as an amplifier circuit. In addition, it is possible to simplify the connection between the microstrip and the waveguide and to form a hermetically sealed structure.
It is possible to enhance the signal isolation between the waveguide of the interface and other circuits.

Although the above-described embodiment is a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

[0018]

As is apparent from the above description, claim 1
In the microstrip waveguide conversion circuits described in 1 to 4, the waveguide and the dielectric substrate are arranged substantially vertically, and the waveguide is terminated by a conductor such as an iron plate. Is shielded. Therefore, the leak of the transmission signal is gradually reduced, isolation between the waveguide and the other circuit can be obtained, and adverse effects on the amplifier circuit and the like can be reduced. In particular,
It is advantageous when a hybrid IC is used.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view showing a first embodiment of a microstrip waveguide conversion circuit of the present invention, showing a state of connection between a microstrip and a waveguide.

FIG. 2 is a side view of the A-A ′ cross section of FIG. 1.

FIG. 3 is a diagram showing a pass loss characteristic and an input return loss characteristic of the embodiment of FIG.

FIG. 4 is a plan sectional view showing a second embodiment of the microstrip waveguide conversion circuit of the present invention, and is a view showing a state of connection between the microstrip and the waveguide.

FIG. 5 is a plan sectional view showing a third embodiment of the microstrip waveguide conversion circuit of the present invention, and is a view showing a state of connection between the microstrip and the waveguide.

6A and 6B are diagrams showing a connection example between a conventional microstrip and a waveguide, where FIG. 6A is a sectional view taken along line BB ′ in FIG. 6B and FIG. 'It is a sectional view.

FIG. 7 is a side sectional view showing a connection example between a conventional microstrip and a waveguide.

[Explanation of symbols]

 1, 11 Waveguide 2, 12 Ridge 3 Gold ribbon 4 Tapered line 5, 15 Microstrip line 6 Metal plate 7, 17 Dielectric substrate 18 Through hole 19 Dielectric substrate for sealing

Claims (4)

[Claims] 1. A dielectric substrate having a microstrip line formed therein, and a waveguide having a ridge provided on an E surface, wherein the waveguide and the dielectric substrate are arranged substantially vertically. The microstrip waveguide conversion circuit, wherein the ridge and the microstrip line are electrically connected, and the waveguide is terminated by a conductor. 2. The microstrip waveguide conversion circuit according to claim 1, wherein the electrical connection between the ridge and the microstrip is a connection using a gold ribbon. 3. The electrical connection between the ridge and the microstrip is a connection in which a through hole is provided in the dielectric substrate and a bonding wire is used in the through hole. Microstrip waveguide conversion circuit. 4. The microstrip waveguide conversion circuit according to claim 1, wherein the waveguide is entirely covered with a dielectric and is covered.