JPH09167825A - Composite microwave integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a composite microwave integrated circuit, prevent external interference from being applied, and enhance airtightness and heat dissipating properties by a method wherein a high-frequency module and an antenna are assembled into one piece. SOLUTION: A ground conductor plane is provided to the upside and downside of a dielectric multilayered substrate, a viahole which short-circuits the two ground planes is connected to form the ground planes into one piece. A slot 8 serving as a feeder for an antenna 7 or an antenna 7 is provided to a part of the ground plane on the same direction with a semiconductor mounting surface. An upper layer and a lower layer are aligned with an intermediate layer as accurate as required, and then a patterning or a mounting operation is carried out, whereby excellent characteristics of this constitution can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave integrated circuit, and more particularly to a composite microwave integrated circuit used for a communication device such as a microwave and a millimeter wave on which a plurality of semiconductor chips using a dielectric multilayer substrate are mounted. About.

[0002]

2. Description of the Related Art In a microwave composite integrated circuit used for a communication device or the like, a dielectric substrate is welded to a metal base plate. Then, a semiconductor element or the like is mounted on a dielectric substrate, assembled into a package, and an antenna is configured through an interface such as a waveguide or a coaxial line.

FIG. 4 shows a conventional external view of such a microwave composite integrated circuit. FIG. 4 shows a configuration in which a transmission high-frequency circuit for a microwave band or the like is mounted.

Here, reference numeral 1 denotes a dielectric multilayer substrate, and reference numeral 2 denotes a metal base plate welded to the dielectric multilayer substrate 1. In the dielectric multilayer substrate 1, the uppermost layer and the lowermost layer are conductor layers. In the middle layer, an oscillator 4, an amplifier 6, a mixer 12, and a bandpass filter 13 of a high-frequency circuit are formed.
Further, the output of the bandpass filter 13 is an attenuator (ATT) 1
The signal is input to a high-frequency power amplifier (PA) 6 through a signal line 4.
The output of the PA 6 is connected to the output terminal 15 through a microstrip line.

The above-described oscillation circuit 4, amplifier 6, mixer 12, attenuator 14, and PA 6 are all mounted on the middle layer of the dielectric layer. Further, holes are formed by cutting from the surface layer to the middle layer, thereby facilitating mounting and adjustment of each high-frequency component. In addition, these holes were electrically shielded by a metallic cap 10.

The high-frequency signal output from the output terminal 15 is connected to an antenna provided on the dielectric multilayer substrate 1.

FIG. 5 is a sectional view showing the structure from the output terminal portion 15 to the antenna connection. The signal passed through PA6 is supplied to the coaxial line through the coaxial-stripline conversion circuit of the output terminal section 15 as shown in FIG. The final antenna unit is interfaced via a waveguide 16 including a casing 17 having a coaxial-waveguide conversion circuit.

In the figure, reference numeral 2 denotes a base plate,
19 is a supporting dielectric for the coaxial center conductor, 20 is the center conductor of the coaxial line, 18 is the coaxial waveguide conversion antenna, and 21 is the ground contact metal plate.

[0009]

In a microwave composite integrated circuit, a high-frequency circuit is formed in a dielectric multilayer substrate surrounded by conductor layers, and a reinforcing plate capable of dissipating heat is attached to the back surface. In this structure, not only a complicated structure such as stripline-coaxial conversion and coaxial-waveguide conversion is required between the high-frequency circuit and the antenna as shown in FIG. 5, but also the characteristics are affected by mode conversion and the like. There is a problem that it is difficult to secure good characteristics.

With respect to the configuration of the interface between the high-frequency circuit and the antenna, a method that does not use stripline-coaxial conversion or coaxial-waveguide conversion as shown in FIG. 5 is also known.

For example, an antenna device of an active phased array antenna in which an antenna and an amplifier are integrated using both surfaces of a ceramic multilayer substrate is disclosed in
-160635.

In this antenna device, an amplifier such as an IC chip for high frequency amplification is mounted on one surface of a multilayer substrate made of a low-temperature fired ceramic. The multi-layer substrate has a conductor layer of an antenna pattern connected to the amplifier via a via hole on the other surface, and one side of the multi-layer substrate is attached to a motherboard.

However, in the structure described in the above-mentioned Japanese Patent Application Laid-Open No. 5-160635, it is necessary to feed power to the antenna from a signal circuit connected to an amplifier or the like from the opposite surface via a via hole. For this reason, at a high frequency such as a millimeter wave, when power is supplied through a via hole, a phenomenon such as mode conversion occurs, and it is difficult to secure characteristics. Further, since the wavelength of the millimeter wave is short, the influence of positional shift between layers and the like is remarkable, and it is difficult to form the antenna on the opposite surface in manufacturing.

Furthermore, in the structure disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-160635, low-temperature fired ceramics generally have high thermal resistance, and it is necessary to adopt a structure taking heat dissipation into consideration when mounting a semiconductor element. There are difficulties. In addition, since it does not have an airtight sealing structure, there is a problem in reliability when mounting an IC chip for high frequency use.

An example of another antenna is an MMIC (Monolithic micro) as shown in FIG.
Wave integrated circuits are known.

In FIG. 1, a microstrip line 41 is provided below a GaAs substrate 43, and a GaAs substrate 43 is provided.
A slot 42 crossing the microstrip line 41 is provided in the upper layer. Then, the substrate 44 having a low dielectric constant is attached on the GaAs substrate 43, and the antenna patch 45 is provided on the substrate 44.

This antenna also has an advantage that it can be configured without using a stripline-coaxial conversion, a coaxial-waveguide conversion, or the like.

However, since this antenna is used for an MMIC, it does not constitute an antenna integrally with a multilayer substrate. Microstrip line 4
Since 1 and the patch 45 appear on the surfaces of the substrates 43 and 44, it is difficult to take a high-frequency shield. Further, it is difficult to release heat.

The most problematic point of this antenna is that
Since it is necessary to attach the GaAs substrate 43 and the dielectric substrate 44, there is a problem in that the attachment accuracy cannot be secured. As a result, the positional deviation between the center of the slot 42 of the GaAs substrate 43 and the center of the dielectric substrate 44 has a problem that an antenna feed loss increases and antenna radiation characteristics deteriorate.

As described in detail above, an object of the present invention is to solve the problem in the conventional antenna configuration, and to form an antenna integrally with a multilayer substrate constituting a high-frequency circuit without using a waveguide or the like. Another object of the present invention is to provide a microwave composite integrated circuit capable of further improving characteristics in consideration of airtightness, interference, and heat radiation.

[0021]

To achieve the above object, the present invention relates to a composite microwave integrated circuit having a plurality of high-frequency circuits mounted on an inner layer of a dielectric multilayer substrate. Layers are formed on the uppermost layer and the lowermost layer, the two ground layers are connected by via holes to form an integrated structure, a planar antenna substrate is mounted on the uppermost layer to form an antenna, and a base plate is formed on the lowermost layer. Attach. In the antenna, a slot is provided in the uppermost layer of the dielectric multilayer substrate below the planar antenna substrate, and a microstrip line for strip-slot coupling with the slot is provided in the inner layer.

Further, the antenna may be configured such that an opening is provided in the dielectric multilayer substrate below the planar antenna substrate, and a slot provided in a lower surface of the planar antenna substrate and a lower portion of the opening. Strip-slot coupling is performed with a microstrip line provided on the layer surface. In this case, it is preferable that the antenna substrate is a translucent substrate and an opening corresponding to the positioning display position provided on the inner layer surface is provided.

By integrating a high-frequency circuit module and an antenna in a dielectric multilayer substrate surrounded by two short-circuited conductor layers, an electric shield can be obtained, so that interference from the outside can be obtained. Can be prevented. Basically, since the antenna is arranged on the semiconductor mounting surface, a reinforcing plate also serving as a heat radiator can be provided on the back surface, so that the heat resistance is low, and it is possible to mount components with large power consumption. By mounting the antenna on the semiconductor mounting surface, it is possible to perform positioning with high accuracy of the antenna pattern on the middle layer signal circuit and the upper layer.

[0024]

FIG. 1 is an external view of a composite microwave integrated circuit showing a first embodiment of the present invention. FIG.
Has a structure similar to the structure shown in FIG. 4, and the difference is mainly in the antenna connection structure.

A conductor layer for ground is formed on two layers of the dielectric substrate 1 which are superposed on each other, for example, the upper surface and the lower surface of each of the uppermost layer and the lowermost layer. Microstrip lines 22 for signal transmission are formed in one or more conductor layers in an intermediate layer between the upper and lower layers of the dielectric substrate. As will be described later, the signal circuit is configured so that via holes are arranged between the two ground conductor layers so as to sandwich both sides of the signal circuit substantially along the signal circuit so as to improve the shield and antenna feeding characteristics.

A hole 23 is formed in the dielectric layer above the middle layer for signal transmission, and an oscillation circuit 4, a frequency multiplier 5, an amplifier 6, etc. are formed at positions corresponding to the signal transmission section.
A semiconductor element such as an MIC is mounted inside, and the hole thus formed is covered with a conductor plate (cap) 10 after the semiconductor element is mounted.

The antenna feed circuit is formed by forming a slot 8 in the direction crossing the microstrip line 22 on the ground surface in the direction in which the semiconductor element is mounted.

The slot 8 forms an output as it is as an antenna as a slot antenna.

Further, since the slot 8 is used as a power supply circuit,
The low dielectric constant planar antenna substrate 7 provided with the antenna pattern is mounted on the slot 8.

In manufacturing such as forming the slot 8 on the ground surface or mounting the substrate 7 having an antenna pattern, accurate positioning is required. Therefore, a mark 9 for alignment (positioning) is formed on the layer of the microstrip line 22 of the middle signal circuit on the multilayer substrate, and a hole 31 is formed on the dielectric substrate 1 on the upper layer when patterning is performed. Make a match.

In this embodiment, as described above, the main high-frequency circuit section is formed on the dielectric multilayer substrate, and the shielded antenna feed section is basically formed on the ground plane. Therefore, portions other than the antenna of the interface section are shielded, and are less susceptible to external interference or the like. Furthermore, a plate for heat dissipation and reinforcement can be provided on the opposite surface, and a hermetic sealing structure can be used, so that a bare chip can be used. Also, in the antenna feed section, since the upper layer and the middle layer have positioning accuracy, the upper layer is aligned with the pattern of the lower layer to achieve the positioning accuracy.

FIG. 2 is a diagram showing the structure of the composite microwave integrated circuit in which the via holes 24 are specifically arranged and formed in the antenna feeding circuit of FIG.

The composite microwave integrated circuit shown in FIG. 1 employs a microstrip line using a coplate line as a part of the dielectric multilayer substrate 1. The via hole 24 is provided so as to connect between the upper and lower conductors of the dielectric multilayer substrate 1. The via holes 24 are arranged along and around the microstrip lines such as the microstrip line 22 and the coplate line. This allows
This has the effect of reducing the coupling of mutual signals between circuit blocks and wiring patterns.

In particular, by arranging the antenna feeding slot 8 so as to surround it, the strip-slot coupling is improved and the efficiency is improved, and the effect of unnecessary high frequency which is likely to occur at this coupling portion is effectively suppressed. There is also an effect.

An external view of the second embodiment of the present invention is shown in FIG. In the present embodiment, the antenna portion is not formed as a slot of the upper surface ground, but a hole 32 is formed up to an intermediate dielectric having a microstrip line, and a conductor surface having a slot 33 on the lower surface and an antenna pattern provided on the upper surface. The substrate 11 is used. The lower surface of the antenna substrate 11 is connected to the upper surface ground of the multilayer substrate 1 so as to cover the hole 32. In this case, the substrate 11 provided with the planar antenna is made of quartz or another transparent material, and the conductors on the lower surface of the middle layer substrate and the substrate 11 are respectively aligned.
By providing the openings 34, the patterns can be aligned with each other.

[0036]

As described above, according to the present invention, a module part and an antenna part are integrated with a high-frequency circuit in a dielectric multilayer substrate surrounded by two conductor layers which are short-circuited by a via hole. This has the effect of omitting the waveguide connection previously required.

Further, since an electric shield can be taken, there is also an effect of preventing external interference. Also, since the antenna is basically arranged on the semiconductor mounting surface, it is possible to attach a reinforcing plate that also serves as heat dissipation, resulting in low thermal resistance,
An airtight sealing structure capable of mounting components with high power consumption also has the effect of improving reliability.

Furthermore, by performing patterning or mounting while aligning the upper layer and the middle layer where alignment accuracy is required, it is possible to secure the characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of an antenna feed circuit of FIG. 1;

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is an external view of a conventional microwave composite integrated circuit.

5 is a cross-sectional view showing a structure from an output terminal portion to an antenna connection in FIG.

FIG. 6 is a view showing the structure of a conventional MMIC antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric multilayer board 2 Base plate (heat sink) 3 Power supply connector 4 Voltage controlled oscillator (VCO) 5 Frequency multiplier (MULT) 6 Amplifier 7 Antenna board 8 Antenna feeding slot 9 Middle-upper-layer matching pattern 10 Cap (CAP) 11) Antenna substrate (translucent substrate) 12 Mixer (MIX) 13 Bandpass filter (BPF) 14 Attenuator (ATT) 15 Output terminal 16 Antenna feed waveguide 17 Housing 18 Coaxial waveguide conversion antenna 19 Support Dielectric for spring 20 Spring center conductor 21 Metal plate for ground contact 22 Signal circuit 23 Hole 24 Via hole

Claims (6)

[Claims] 1. A composite microwave integrated circuit having a plurality of high-frequency circuits mounted on an inner layer of a dielectric multilayer substrate, wherein a ground conductor layer is formed on an uppermost layer and a lowermost layer on the dielectric multilayer substrate, and the two grounds are provided. A composite microwave integrated circuit, wherein a conductor layer for connection is connected by a via hole to form an integrated structure, a planar antenna substrate is mounted on the uppermost layer to form an antenna, and a base plate is mounted on the lowermost layer. 2. The antenna according to claim 1, wherein a slot is provided in an uppermost layer of the dielectric multilayer substrate below the flat antenna substrate, and a microstrip line for strip-slot coupling with the slot is provided in the inner layer. 2. The composite microwave integrated circuit according to claim 1, wherein: 3. A positioning display is provided on an inner surface of the dielectric multilayer substrate, and a first opening is provided from an uppermost layer to an inner surface of the dielectric multilayer substrate corresponding to the positioning display. The composite microwave integrated circuit according to claim 1. 4. The antenna, wherein a second opening is provided in the dielectric multilayer substrate below the planar antenna substrate,
The composite microwave integration according to claim 1, wherein strip-slot coupling is performed by a slot provided on a lower surface of the planar antenna substrate and a microstrip line provided on an inner layer surface below the second opening. circuit. 5. The composite micro-device according to claim 4, wherein said planar antenna substrate is a light-transmitting substrate, and a third opening is provided corresponding to said positioning display position provided on said inner layer surface. Wave integrated circuit. 6. The composite microwave integrated circuit according to claim 1, wherein a plurality of said via holes are provided along both sides of said microstrip line.