JPH0590803A - Multilayer microwave circuit - Google Patents

Abstract

PURPOSE:To provide a multilayer microwave circuit which can suppress the generation of a parallel plate mode and keep the satisfactory electric characteristic. CONSTITUTION:A multiplayer microwave circuit contains a triplet line consisting of the ground conductor members 6 and 9 which hold vertically a center conductor 8 via the dielectric members 2 and 3. In such a constitution, at least one of both members 2 and 3 and the members 6 and 9 have the similar shapes as the conductor 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer microwave circuit including a triplate line.

[0002]

2. Description of the Related Art Array antennas in the future are required to have various performances such as beam scanning, beam shaping, and low side lobe. For this purpose, an active phased array antenna including an LNA (low noise amplifier), HPA (high power amplifier) and a phase shifter is required. Moreover, since the demand for moving objects such as airplanes and automobiles is most expected, the array antenna including the power feeding circuit and the like can be downsized.
It is required to build a thin type.

By the way, the miniaturization and thinning of the antenna can be dealt with by using the microstrip antenna, and the microstrip line can also be used for the construction of the feeding circuit. In particular, it is effective that the feed circuit can be stacked in multiple layers by using the triplate line as a separate layer, and these elements can be integrated into the triplate line by making the MMIC of the active element such as LNA and HPA. Can also be incorporated into. With the above configuration, it can be said that the array antenna that realizes advanced functions can be made extremely small and thin.

However, as a problem in using the triplate line, there is an occurrence of a parallel plate mode which is an unnecessary mode. The parallel plate mode occurs in the structure of the triplate line where it is connected to upper and lower layers, connectors, etc. and is asymmetrical between the upper and lower structures, and has electrical characteristics such as matching characteristics and radiation directivity. Adversely affect.

As a concrete example, FIGS. 11 and 12 show a four-element array antenna using a slot-coupled feed type microstrip antenna.

FIG. 11 is a top view of a 4-element array antenna, and FIG. 12 is a sectional view thereof. Where connector 5
The radio wave input from 1 is divided into four by the central conductor 52 and each excites the patch 54 through the slot 53. At this time, the parallel plate mode is generated in the portion where the slot 53 is provided on the triplate line and the connection point 57 with the connector 51 which is vertically asymmetrical. The parallel plate mode propagates between the outer conductors 55 and 56 forming the triplate line and reaches the end of the substrate.
The electric field generated here contributes to the radiation field and affects the radiation field of the array antenna. In addition, the parallel plate mode generated in the triplate line resonates, which affects the resonance characteristics of the antenna.

[0007]

As described above, the conventional multi-layer microwave circuit has a problem that the electrical characteristics are adversely affected by the occurrence of the parallel plate mode.

Therefore, an object of the present invention is to provide a multi-layer microwave circuit which suppresses the occurrence of a parallel plate mode and maintains good electric characteristics.

[0009]

In order to solve the above problems, the present invention provides a multi-layer microwave circuit having a triplate line in which a ground conductor member is provided on a central conductor from above and below via a dielectric member. In the above, at least one of the dielectric member and the ground conductor member has a shape along the center conductor.

[0010]

According to the present invention, since the dielectric member and the ground conductor member forming the triplate line are formed along the central conductor, there is no room for the generated parallel plate mode to spread to other than the triplate line. Unnecessary radiation sources are not concentrated at the ends of the dielectric member. Therefore, the occurrence of the parallel plate mode is suppressed in the triplate line forming the multilayer microwave circuit, and the electrical characteristics are not adversely affected.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing an embodiment in which the multilayer microwave circuit of the present invention is applied to a four-element array antenna provided with a feeding circuit, and FIG. 2 is a sectional view thereof.

The array antenna shown in the figure is constructed by stacking three dielectric substrates 1, 2, and 3. The upper dielectric substrate 1 has a rectangular shape, and four sets of rectangular patches 4, 4 ... Are formed on the surface by a conductor film, and the back surface thereof corresponds to the patches 4, 4, ... As shown in FIG. And then slots 5, 5
The conductor film 6 provided with ... Is formed. The conductor film 6 is also one of the constituent elements of the triplate line (ground conductor in the claims).

On the surface of the lower dielectric substrate 3, a central conductor 8 (a central conductor in the claims) which is one of the constituent elements of a triplate line is formed by a conductor film, and on the back surface thereof, the triplate is formed. A ground conductor 9 (ground conductor in the claims), which is one of the constituent elements of the line, is formed of a conductor film, and a connector 10 is provided. The external contact 11 of this connector 10 is connected to the ground conductor 9, and the center contact 12 is connected to the center conductor 8 via a conductor pin or through hole 13 that penetrates the lower dielectric substrate 3. The center conductor 8 connected to the center contact 12 is branched in four directions at the center of the substrate, and each branched center conductor 8 is extended so as to intersect with each slot 5.

Here, unlike the upper dielectric substrate 1 having a rectangular shape, the middle dielectric substrate 2 and the lower dielectric substrate 3 (including the ground conductor 9) have a shape along the central conductor 8. Has been done. That is, the middle dielectric substrate 2 and the lower dielectric substrate 3 are surrounded by the triplate line, or the part sandwiched between the triplate lines and not operating as the triplate line is removed.

Next, the operation of the array antenna thus constructed will be described.

The electric wave fed from the connector 10 is divided into 4 in the central conductor 8 and then electromagnetically coupled to each patch 4 through the slot 5 at a position where it crosses each slot 5 to excite each patch 4. .. As a result, radio waves are radiated from each patch 4 to operate as an array antenna.

Here, as described in the conventional example, the parallel plate mode occurs at the connection point 7 of the slot 5 and the connector 10. However, the middle dielectric substrate 2
The lower dielectric substrate 3 is removed except for the shape along the triplate line, that is, the portion that operates as a triplate line, so that there is no room for the generated parallel plate mode to spread to other than the triplate line. Unwanted radiation sources will not be concentrated on the edges of the dielectric substrate 2 and the lower dielectric substrate 3. Therefore, the influence of the generated parallel plate mode on the radiation field of the array antenna is reduced. In addition, since the shape of the region in which the parallel plate mode propagates, that is, the dielectric substrate 2 in the middle and the dielectric substrate 3 in the lower part is not regular like a rectangle but irregular, resonance is hard to occur or the substrate The unwanted sources of radiation that occur at the edges of are also irregular. Therefore, the influence of the generated parallel plate mode on the characteristics of the microwave circuit formed on the antenna or the substrate is reduced.

Since the main portion that operates as a triplate line is a portion within 5 to 6 times the width of the central conductor 8 from the central conductor 8, a dielectric other than this portion (dielectric in the middle portion) Even if the substrate 2 and the lower dielectric substrate 3), the upper ground conductor (the conductor film 6 provided with the slots) and the lower ground conductor (ground conductor 9) are removed, the influence on the microwave circuit characteristics is small. Therefore, in the above-described embodiment, the upper ground conductor (the conductor film 6 provided with the slots) serves as the ground conductor for the patch antenna, so that a part of the lower ground conductor (ground conductor 9) is removed as it is. However, the present invention also includes the removal of either the upper ground conductor or the lower ground conductor, and the removal of both the upper ground conductor and the lower ground conductor.

Further, although the main purpose of the present invention is to suppress the occurrence of the parallel plate mode and maintain good electric characteristics as described above, the following effects can be expected by the constitution of the present invention.

First, inside the feeding circuit, even if the lines approach each other, the portions of the dielectric and conductor between the lines are removed, so that the electrical coupling between the lines can be suppressed, and the design of the feeding circuit can be suppressed. -Manufacturing can be facilitated. In this case, it is conceivable to remove the dielectric material and the conductor from the central conductor 8 even within a portion of 5 to 6 times its width, mainly for the purpose of reducing the electrical coupling between the lines.

Further, in the multilayer microwave circuit of the present invention, since the excess portions of the dielectric and the conductor are removed, the weight is reduced. Therefore, it is effective as an on-board antenna of, for example, artificial satellites or airplanes, which requires the entire antenna to be lightweight.

Furthermore, since a part of the power supply circuit is vacant, it becomes possible to pass a heat pipe or the like for controlling heat generated from the active element or the like through this vacant part. Therefore, for example, it is effective as a microwave circuit for mounting on a satellite that requires heat control.

In the case of array antennas for aircraft,
Although it is required to form the antenna and the power feeding circuit in a curved shape in accordance with the shape of the aircraft, since the multilayer microwave circuit of the present invention has a cavity, it is possible to bend a planar configuration into a curved shape. It is effective that it is performed relatively easily.

Next, another embodiment of the present invention will be described.

FIG. 4 is a diagram showing a circuit configuration of the active array antenna according to this embodiment. In the figure,
Reference numeral 14 is an antenna element for both transmission and reception, and this antenna element 14 is connected to a MIC (MMIC) module 15.

Here, the MIC module 15 is manufactured separately from the multilayer microwave circuit, and is connected to the multilayer microwave circuit by a connector or the like.

In the MIC module 15, the antenna element 14 is connected to the demultiplexer 16, and the demultiplexer 16 separates the transmission and reception radio waves. An HPA 17 and a phase shifter 18 are connected to the transmission side of the demultiplexer 16, and the phase shifter 18 is a transmission power feeding circuit 19 in the multilayer microwave feeding circuit.
It is connected to the. The receiving side of the demultiplexer 16 has an LNA2
0 and the phase shifter 21 are connected, and the phase shifter 21 is connected to the reception power feeding circuit 22 in the multilayer microwave power feeding circuit.

FIG. 5 is a sectional view showing the structure of this active array antenna.

As shown in the figure, this active array antenna has five dielectric substrates 23, 24, 25 and 2.
6 and 27 are stacked.

A patch 28 is formed on the surface of the uppermost dielectric substrate 23, and a conductor surface 29 is formed on the back surface.

The receiving and feeding circuit 22 formed of a triplate line is formed on the front surface of the third dielectric substrate 25 from the top, and the conductor surface 30 serving as the outer conductor of the triplate line is formed on the back surface thereof. ..

On the surface of the lowermost dielectric substrate 27, a transmission power feeding circuit 19 composed of a triplate line is formed,
A conductor surface 31 which is an outer conductor of the triplate line is formed on the back surface.

Here, the patch 28 is connected to the MIC module 15 arranged on the back surface of the lowermost dielectric substrate 27 via conductor lines 32 penetrating these dielectric substrates 23 to 27.

The reception output terminal of the MIC module 15 is
It is connected to the reception power feeding circuit 22 via a conductor wire 33 penetrating the dielectric substrates 25 to 27.

The combined output terminal of the reception power feeding circuit 22 is connected to the connector 35 via the conductor wire 34 penetrating the dielectric substrates 25 to 27.

The transmission output terminal of the MIC module 15 is
It is connected to the transmission power supply circuit 19 via a conductor wire 36 penetrating the dielectric substrate 27.

The composite output terminal of the transmission power supply circuit 19 is connected to the connector 38 via the conductor wire 37 penetrating the dielectric substrate 27.

The conductor lines 32, 33, 34, 36, 37 for connecting the lines between the upper and lower layers are surrounded by the conductor lines 39, 40, 4 so as to surround the conductor lines in order to match the connection.
1, 42, 43 are provided respectively.

Incidentally, these conductor lines 32 to 34, 36,
The conductors 37, 39 to 43 may be formed by soldering conductor pins or the like, or may be formed by through holes.

Here, FIG. 6 is a view of the surface of the uppermost dielectric substrate 23 viewed from above, and FIG. 7 is a view of the back surface thereof viewed from below. 8 is a view of the surface of the third dielectric substrate 25 from the top, and FIG. 9 is the fourth dielectric substrate 2 from the top.
It is the figure which looked at the surface of 6 from the top.

In this embodiment, as shown in FIG. 8, in the second and third dielectric substrates 24 and 25 from the top, the dielectric portion and the conductor portion not related to the receiving and feeding circuit are removed.

Similarly, as shown in FIG. 9, in the fourth and lowermost dielectric substrates 26 and 27 from the top, the dielectric and conductor portions not related to the transmission power feeding circuit are removed.

However, in this embodiment, the dielectrics near the ends of the dielectric substrates 24 to 27 are left in consideration of the strength and flatness of the multilayer substrate.

With such a structure, it is possible to prevent unnecessary propagation of the parallel plate mode generated in the feeding circuit and electrical coupling between the lines, as in the first embodiment.

Further, since unnecessary dielectrics are removed, the weight can be reduced. In particular, when the array antenna has a very large number of elements or the power feeding circuit is composed of many layers, the effect of reducing the weight is great.

In this embodiment, the example in which the MIC module is provided outside the multilayer substrate has been described.
It is also conceivable to form the (MMIC) component in layers and to incorporate it in each feeding circuit. In this case, electrical coupling between the lines can be prevented, which has the advantage of increasing the degree of freedom in arrangement and configuration of the MIC components.

By the way, in a multi-layer microwave circuit, if there are many connections between the upper and lower layers, and the number of through holes and the relationship of the layers to be connected are different, manufacturing becomes difficult. Therefore, as an application example of the present invention, a multilayer microwave circuit capable of simplifying the manufacturing process will be described with reference to FIG.

Comparing the multilayer microwave circuit shown in FIG. 10 with that shown in FIG. 5, a portion where the upper and lower connections were made through the dielectric substrate by utilizing the conductor wire (through hole) (shown in FIG. 5). Reference numerals 32, 33, 34, 36, 37)
Regarding, the part of the dielectric substrate is removed and the coaxial line or the connector is directly connected.

For example, the connector 44 and the coaxial line 45 are directly provided on the back surface of the dielectric substrate 25 on which the reception power feeding circuit 22 is formed.
Is attached.

That is, with this structure, the through holes of the dielectric substrates 24 and 25 and the through holes of the dielectric substrates 26 and 27 can be separately processed, and the manufacturing process is simplified.

Depending on the location, screwing with a metal screw may be used instead of the through hole, which is convenient in terms of cost.

In the above description, the case where the substrate in which the conductor pattern is formed on the dielectric is made multi-layered has been described. However, the same effect can be obtained by using other supporting members such as expanded polystyrene and paper honeycomb instead of the dielectric. Is obtained.

[0054]

As described above, according to the present invention, it is possible to prevent unnecessary propagation of the parallel plate mode and deterioration of the electrical characteristics of the multilayer microwave circuit due to coupling between lines. Further, since the excess parts of the dielectric and conductor are removed, the weight of the entire antenna can be reduced, which is effective as an antenna for mounting on a satellite or an aircraft. In addition, since a part of the power supply circuit is vacant, it is possible to pass a heat pipe or the like for controlling the heat generated from the active element, etc., and the degree of freedom in arrangement and configuration of the active element itself is increased. There are advantages to increase. Furthermore, it is easy to deform the multilayer microwave circuit configured with a plane into a curved surface,
This is effective for an antenna formed on a curved surface of an aircraft or the like.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a multilayer microwave circuit according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a view of the back surface of the upper dielectric substrate of FIG. 1 viewed from below.

FIG. 4 is a diagram showing a circuit configuration of an active array antenna according to another embodiment of the present invention.

5 is a cross-sectional view showing the structure of the active array antenna of FIG.

FIG. 6 is a view of the surface of the uppermost dielectric substrate of FIG. 4 as viewed from above.

7 is a bottom view of the back surface of the uppermost dielectric substrate shown in FIG. 4;

FIG. 8 is a view of the surface of the third dielectric substrate from the top of FIG. 4 as viewed from above.

9 is a view of the surface of the fourth dielectric substrate from the top of FIG. 4 as viewed from above.

FIG. 10 is a sectional view of a multilayer microwave circuit according to another embodiment of the present invention.

FIG. 11 is a top view of a conventional multilayer microwave circuit.

12 is a cross-sectional view of FIG.

[Explanation of symbols]

1, 2, 3 ... Dielectric substrate, 4 ... Patch, 5 ... Slot,
6, 9 ... Ground conductor, 8 ... Center conductor, 10 ... Connector, 13
… Conductor pins or through holes.

Claims (1)

[Claims] 1. In a multi-layer microwave circuit having a triplate line in which a ground conductor member is provided from above and below with respect to a central conductor, at least one of the dielectric member and the ground conductor member is provided. A multilayer microwave circuit having a shape along the center conductor.