JP3288736B2 - Active phased array antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active phased array antenna which can be suitably used for mobile satellite communications for mobiles such as automobiles, ships, aircrafts, etc. using a satellite, and more particularly to a ceramic multilayer antenna. The present invention relates to an active phased array antenna using a substrate.

[0002]

2. Description of the Related Art Generally, a phased array antenna is
A plurality of antenna elements are arranged on a substrate, and it is possible to form a beam that changes the shape of the beam itself by controlling the phase and amplitude of each antenna element. For this reason, the sensitivity to unnecessary interference waves can be reduced or eliminated. In addition, by electronically changing the phase of each antenna element, the antenna beam can be spatially scanned at high speed. The phased array antenna having such characteristics has been mainly used in the field of radar until now, but has recently been considered for introduction in the field of mobile satellite communication. Recently, the development of microwave integrated circuit (hereinafter referred to as microwave IC) technology has made it possible to reduce the size and weight of microwave circuit elements such as amplifiers and phase shifters. An active phased array antenna having integrated microwave circuit elements, that is, one in which each antenna element has functions such as amplification, phase shift, and frequency conversion, has been realized.

[0003]

However, although the active phased array antenna thus realized is integrated, a unit of a reception low noise amplifier or a transmission power amplifier is arranged behind the antenna element, and the antenna element and the antenna element are connected to each other. The units are connected by a connector or the like, and there are problems in wiring, assembly, downsizing, and the like. In addition, when a Teflon (registered trademark) substrate, which is generally used in a microwave region, is used as a substrate on which an antenna element is disposed for integration, a support structure having mechanical strength is necessary because the Teflon substrate is flexible. When a normal high-temperature fired ceramic substrate with sufficient mechanical strength is used, a material such as molybdenum or tungsten with a high melting point must be used as the conductive metal, so that the resistance value increases, making it suitable for high-frequency applications. There was a drawback that it was not suitable. Therefore, a substrate that can be suitably used as a substrate for an antenna as well as for a high-frequency circuit has been desired.

Accordingly, an object of the present invention is to provide an active phased array antenna using a ceramic multilayer substrate capable of reducing the loss by downsizing the circuit, further downsizing the entire circuit, improving the antenna characteristics, and the like. To offer.

[0005]

An active phased array antenna according to the present invention comprises a conductor layer of an antenna pattern formed on one surface of a ceramic multilayer substrate and the conductor layer formed on the other surface of the ceramic multilayer substrate. An amplifier connected to the feed point of the layer and a ceramic multilayer board
Embedded in the board and electrically connected to the conductor layer and the amplifier
An antenna unit comprising a shielded internal conductor for shielding and a terminal for obtaining electrical connection between the amplifier and the outside.

The ceramic multilayer substrate is preferably a low-temperature fired ceramic multilayer substrate made of glass ceramic.

[0007] Further, a copper or silver-based material can be used for the conductor layer.

Further, the antenna unit is configured as a transmitting antenna unit and a receiving antenna unit, respectively, and the transmitting antenna unit and the receiving antenna unit can be arranged in a mixed manner.

It is preferable that the transmitting antenna unit and the receiving antenna unit which are arranged in a mixed manner are arranged adjacently and alternately in a grid pattern.

[0010]

According to the active phased array antenna of the present invention, since the antenna pattern is formed on the low-temperature fired ceramic multilayer substrate having a higher dielectric constant than the Teflon substrate, the circuit size can be reduced by shortening the wavelength. In addition, a low-temperature fired ceramic multilayer substrate does not require a special support structure because of its high mechanical strength, and can use a copper or silver-based metal material having high conductivity as a conductor, so that a high-frequency circuit substrate can be used. Is also effective.
Therefore, the loss can be reduced by downsizing the circuit, the size of the entire circuit can be further reduced, the antenna characteristics can be improved, and the like.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an active phased array antenna according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an external perspective view of an essential part of an antenna unit of an active phased array antenna according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a ceramic multilayer substrate produced by sintering a ceramic material made of alumina powder, glass powder, and the like at a low temperature in a manufacturing process described below. One surface of the ceramic multilayer substrate 10 has a low resistivity. An antenna pattern 12 which is an antenna element made of a silver-based conductive metal such as copper or silver-palladium is formed. From the feed point 14 of the antenna pattern 12, the conductor of the via hole 16, the internal conductor 18,
A high-frequency amplifier IC chip 22 provided on the other surface of the ceramic multilayer substrate 10 via a bonding wire 20 or the like;
Hybrid IC composed of chip capacitor 24, etc.
(Hereinafter, referred to as an HIC unit) 26.

The antenna pattern 12 and the HIC 2
6 is provided with a large-area internal conductor 28 for shielding, and this internal conductor 28 is configured to be connected to the ground level. Pins 30 for mechanical and electrical connection to a motherboard (not shown)
Are provided in the vicinity of the other surface side. In the case of the present embodiment, the ceramic multilayer substrate 10 is configured to have a package shape for accommodating the HIC portion 26, and the HIC portion 26 side of the ceramic multilayer substrate 10 is covered with a cap (not shown). The surface on the antenna pattern 12 can be subjected to a moisture-resistant and weather-resistant coating treatment.

After all, the antenna unit 32 thus configured is a microwave IC having an antenna element on its surface.
To configure an active phased array antenna, a plurality of antenna units 32 are mounted on a motherboard 34 so that LSIs are arranged as shown in FIGS. FIG. 2 is a plan view showing an active phased array antenna in which the antenna unit 32 is configured as a transmitting antenna unit 32-TX and a receiving antenna unit 32-RX, and is arranged alternately in a grid pattern. FIG. 3 is a side view of the active phased array antenna shown in FIG. Note that the motherboard 34 uses a printed circuit board or the like that does not have a problem with high-frequency characteristics.
Print wiring for connecting each antenna unit, wiring for connection to an external control circuit (not shown), and the like are provided on 4.

In the active phased array antenna thus arranged, a desired power supply phase to each antenna unit 32 is electronically controlled by an external control circuit (not shown) to change the radiation beam direction at a high speed. Perform beam forming operation. Therefore, compared to the conventional phased array antenna which performs phase processing and then amplifies, the active phased array antenna is provided with an amplifying circuit in each antenna unit 32 and performs phase processing after amplifying, so that loss during this period is reduced. , Miniaturization becomes possible.

Here, as an example, the frequency band is 1.5 GHz.
In the case of z, the size of the ceramic multilayer substrate 10 of each antenna unit 32 is about 9 cm square. As a result of forming a circular antenna pattern having a diameter of 4 cm on the ceramic multilayer substrate 10, as a characteristic of the antenna element, a gain of about 5 dBi at a point where the gain in the left-hand circularly polarized wave (normal application) is 0 ° is obtained.
The beam width of the antenna is about 100 ° with a 3 dB width, and good antenna characteristics are obtained as a single antenna in a phased array.

FIG. 4 is a process diagram schematically showing a flow of a process for manufacturing a ceramic multilayer substrate of the antenna unit 32 used in the active phased array antenna according to the present invention. The manufacturing process of the ceramic multilayer substrate 10 of the antenna unit 32 will be described below with reference to FIG.

First, in the printing step, a slurry-like ceramic material obtained by mixing alumina powder and glass powder with an organic substance such as PVA (polyvinyl alcohol) as a binder was formed into a sheet having a desired thickness and dried. After forming different via holes at desired locations on a plurality of green sheets and filling the via paste, an antenna pattern or a desired wiring pattern is formed on each green sheet with a copper or silver-based low-melting metal conductive paste. Print and dry.

Next, in a pressing step, a desired number of green sheets having different conductor patterns after the printing step are stacked in a desired number, and are pressed under appropriate pressure and temperature. At this time, the antenna pattern 12 is exposed on one surface as shown in FIG. 1, and the internal conductor 18 and the via hole 16 are appropriately connected at required places inside the ceramic multilayer substrate 10 and the conductor for shielding is provided. A layer 28 is also formed, and an external conductor pattern such as wiring for connecting ICs and other circuit elements is formed on the other surface.

In the cutting step, the green sheets laminated in the pressing step are cut into desired outer dimensions.

The burn-out step is a step of decomposing and evaporating the organic substance of the binder used when forming the green sheet, and is heated at a temperature of about 300 to 400 ° C.

Further, in the firing step, about 900 to 1000
Bake at a low temperature of about ° C. By this firing step, the green sheet becomes a solid ceramic substrate having a dielectric constant of 5 to 8 having sufficient mechanical strength as an antenna circuit substrate.

Finally, the pins 30 which serve to attach the antenna unit 32 to the motherboard 34 and also serve as electrical connection terminals are mounted on the ceramic multilayer substrate 10 by using a suitable brazing material at the positions shown in FIG. Attach.

Thereafter, circuit elements such as a reception low-noise amplifier and a transmission power amplifier necessary for the operation of the active phased array antenna are mounted and capped to complete the antenna unit 32.

[0025]

As is apparent from the above-described embodiment, according to the present invention, a low-temperature-fired ceramic multilayer substrate is used as a substrate of an antenna unit constituting an active antenna array, so that a conventional microwave IC can be used. Compared to the case where a Teflon substrate is used, the circuit size can be reduced by shortening the wavelength because the dielectric constant is high, and the support structure is unnecessary because the mechanical strength is strong. That is, the size of the antenna element is reduced, and the antenna pattern becomes wide-angle.

Further, since the antenna and the wiring are integrally formed, there is an advantage that productivity is high.

Further, since the low-temperature fired ceramic substrate allows the use of a low-resistivity copper- or silver-based conductor, high-frequency characteristics are improved. Therefore, it is effective in reducing the loss by downsizing the circuit, downsizing the entire circuit, and improving the antenna characteristics.

By incorporating the antenna element and the amplifier circuit on the low-temperature fired ceramic multilayer substrate, the antenna can be unitized and miniaturized as a single antenna, and can be inserted into the motherboard and replaced.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention. It is.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an essential part showing an embodiment of an antenna unit constituting an active phased array antenna according to the present invention.

FIG. 2 is a plan view showing an active phased array antenna according to the present invention in which antenna units are configured as a transmitting antenna unit and a receiving antenna unit, and are alternately arranged in a grid pattern.

FIG. 3 is a side view of the active phased array antenna shown in FIG. 2;

FIG. 4 is a process diagram schematically showing a flow of a process of manufacturing a ceramic multilayer substrate of an antenna unit used in an active phased array antenna according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ceramic multilayer board 12 Antenna pattern 14 Feeding point 16 Via hole 18 Inner conductor 20 Bonding wire 22 High frequency amplification IC chip 24 Chip capacitor 26 Hybrid IC part 28 Inner conductor 30 pin 32 Antenna unit 34 Motherboard

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-214205 (JP, A) JP-A-55-90102 (JP, A) JP-A-2-107003 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01Q 23/00 H01Q 21/00-21/29

Claims (5)

(57) [Claims] And 1. A conductive layer of one of the antenna pattern formed on the surface of the ceramic multilayer substrate, an amplifier which is connected to a feeding point to said conductive layer formed on the other surface of the ceramic multilayer substrate, a ceramic multilayer Built into the board,
For a shield electrically connected to the conductor layer and the amplifier
An active phased array antenna, comprising: an antenna unit including an internal conductor of (1) and a terminal for obtaining electrical connection between the amplifier and the outside. 2. The active phased array antenna according to claim 1, wherein said ceramic multilayer substrate is a low-temperature fired ceramic multilayer substrate made of glass ceramic. 3. The active phased array antenna according to claim 1, wherein the conductor layer is made of a copper or silver-based material. 4. The method according to claim 1, wherein the antenna units are respectively configured as a transmission antenna unit and a reception antenna unit, and the transmission antenna unit and the reception antenna unit are arranged in a mixed manner. 2. The active phased array antenna according to claim 1, wherein: 5. The transmitting antenna unit and the receiving antenna unit arranged in a mixed manner,
5. The active phased array antenna according to claim 4, wherein the active phased array antenna is arranged adjacently and alternately in a grid pattern.