JPH07193423A - Monolithic antenna module - Google Patents

Abstract

PURPOSE:To obtain a monolithic antenna module which is small integrated with a RF circuit such as a RF transmission/reception circuit, etc., and has a wide frequency band width. CONSTITUTION:A RF transmission/reception circuit 3 of a coplanar structure and a rectangular patch antenna 6 are provided on the upper surface part of the same semi-insulating substrate 1 and these are electrically coupled by a coupling part 2. A recessed part 8 is provided in the lower direction of the rectangular patch antenna 6 of the semi-insulating substrate 1 and a metallic layer 5 is provided on the lower surface of the semin-insulating substrate 1 except the recessed part 8. The upper surface of a conductive chip carrier 7 is fixed to the lower surface of the metallic layer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monolithic antenna module, and more particularly to a monolithic antenna module used for transmitting or receiving radio waves in an ultrahigh frequency band such as a microwave band and a millimeter wave band, and for transmitting and receiving.

[0002]

2. Description of the Related Art In recent years, with the progress of technologies such as satellite broadcasting, microwave communication, and wireless LAN (local area network) using microwave and millimeter wave band, a wide band, low loss, small and lightweight transmitter / A monolithic antenna with an antenna element integrated with the receiver
Active development of modules.

FIG. 5 is a perspective view showing an example of a conventional monolithic antenna module of this type disclosed in Japanese Patent Laid-Open No. 1-311605.

In FIG. 5, for example, an RF transceiver circuit 3 for transmitting and receiving an RF signal is formed in a monolithic structure on the upper surface of a semi-insulating substrate 1A made of a gallium arsenide material, and a metal is formed on the lower surface of the semi-insulating substrate 1A. A layer 13 is provided.

Further, for example, a rectangular patch antenna 6 is provided as an antenna element on the upper surface of a dielectric substrate 11 made of a tetrafluoride resin material.

A metal layer 1 is formed on the lower surface of the dielectric substrate 11.
4, the radio wave radiated from the square patch antenna 6 toward the metal layer 14 is reflected by the metal layer 14 to be a radio wave radiated above the square patch antenna 6, and the radio wave is emitted from the square patch antenna 6. It has the same phase as the radio wave radiated directly upward.

These semi-insulating substrate 1A and dielectric substrate 11
The semi-insulating substrate 1A and the lower surface of the dielectric substrate 11 are attached to the upper portion of the chip carrier 12 made of a conductive material having a step so that the upper surface of the substrate is in the same plane, The antenna input / output terminal 15 provided in the RF transmission / reception circuit 3 and the input / output terminal 16 provided in the rectangular patch antenna 6 are made to closely face each other.

The antenna connection terminal 15 and the input / output terminal 16 are connected by a bonding wire 17.

Further, instead of the dielectric substrate 11 on which the square patch antenna 6 is attached, a semi-insulating substrate 1A is extended to below the square patch antenna 6, and a square patch is formed on the upper surface of the semi-insulating substrate 1A. The monolithic antenna module having the antenna 6 and directly connected to the antenna connection terminal 15 of the RF transmission / reception circuit 3 is also described in Japanese Patent Publication No. 1-311605.

In this case, the chip carrier 12 can be omitted.

Furthermore, if an RF receiving circuit is used in place of the RF transmitting / receiving circuit 3 described above, a monolithic antenna module dedicated to reception can be obtained, and an RF transmitting circuit can be used instead of the RF transmitting / receiving circuit described above. For example, it can be a monolithic antenna module dedicated to transmission.

In the above description, an example in which a rectangular patch antenna is used as the antenna element has been described, but the antenna element may be arranged monolithically (on the same plane) as the RF transceiver circuit 3. Possible antennas such as circular patch antennas, slot antennas, cross dipole antennas, etc. can be used.

[0013]

In the conventional monolithic antenna module described above, an RF transceiver circuit and a rectangular patch antenna are provided on the same semi-insulating substrate,
In the case of a structure in which these are electrically connected, in order to radiate radio waves efficiently from this rectangular patch antenna, the relative permittivity of the semi-insulating substrate is about 13,
The thickness of the semi-insulating substrate between the rectangular patch antenna and the metal layer 13 provided thereunder is almost semi-insulating as compared with the case where an air layer is used instead of the semi-insulating substrate. The thickness of the air layer must be divided by the square root of the relative permittivity of the substrate.

As described above, when the thickness of the semi-insulating substrate is reduced, the impedance of the rectangular patch antenna fluctuates sharply with respect to the frequency change, and the frequency bandwidth becomes narrow.

Further, as in the monolithic antenna module shown in FIG. 5, a rectangular patch antenna is provided on the dielectric substrate 11, and the dielectric substrate 11 is made of a tetrafluoride resin material or the like and has a relative dielectric constant. When the ratio is set to about 2 to 3, the frequency bandwidth of the rectangular patch antenna can be widened as compared with the case where the rectangular patch antenna is provided on the semi-insulating substrate 1A. Square patch antennas 6 are provided on separate substrates, which are relatively fixed by a chip carrier 12, and
Since it is necessary to connect the RF transceiver circuit 3 and the rectangular patch antenna 6 with the bonding wire 17, the configuration becomes complicated. By using the bonding wire 17, the RF transceiver circuit 3 and the rectangular patch antenna 6 are connected. However, it has a drawback that electrical characteristics are deteriorated due to mismatch and ohmic loss.

Such a drawback is that instead of the rectangular patch antenna, radio waves are simultaneously radiated in both directions perpendicular to the wide surface of the antenna element such as a cross dipole antenna, a circular patch antenna or a slot antenna. The same is true even if antennas of other configurations are used.

[0017]

Means for Solving the Problems The monolithic structure of the present invention
The antenna module is provided with a coplanar RF receiver circuit provided in the vicinity of an upper surface of a semi-insulating substrate and the RF receiver circuit provided on the same surface of the semi-insulating substrate as the RF receiver circuit.
In a monolithic antenna module comprising an antenna element electrically coupled to a circuit, a portion of the semi-insulating substrate immediately below the antenna element is removed by a predetermined depth and the removed portion is removed. A tunnel-shaped recess having a uniform cross-sectional shape orthogonal to the upper surface of the semi-insulating substrate, a metal layer provided on the lower surface of the semi-insulating substrate excluding the recess, and a wide outer surface of the metal layer. And a conductive chip carrier whose upper surface is in contact with and fixed to.

Another monolithic antenna module of the present invention is a coplanar RF receiver circuit provided in the vicinity of the upper surface of a semi-insulating substrate, and on the same surface as the RF receiver circuit on the semi-insulating substrate. A monolithic antenna module having an antenna element electrically connected to the RF circuit, the portion of the semi-insulating substrate immediately below the antenna element being removed by a predetermined depth. The shape of a cross section of the removed portion parallel to the upper surface of the semi-insulating substrate is rectangular, and the size of the shape is larger than the outer shape of the monolithic antenna. It comprises a metal layer provided on the lower surface of the substrate and a conductive chip carrier whose upper surface is in contact with and fixed to the wide outer surface of the metal layer. .

[0019]

The RF transmitter / receiver circuit and the rectangular patch antenna are provided on the upper surface of the same semi-insulating substrate, and these are electrically connected to each other, and the recess is provided in the semi-insulating substrate directly below the rectangular patch antenna. By fixing a conductive chip carrier below the semi-insulating substrate of, and providing a hollow free space portion by the above-mentioned recess and chip carrier below the square patch antenna, The frequency bandwidth of the rectangular patch antenna is made larger than that of the conventional monolithic antenna module of this kind by increasing the distance from the bottom of the cavity part. In addition, the RF transmitter / receiver circuit and the rectangular patch antenna are mounted on the same semi-insulating substrate, and the two are directly electrically coupled to each other to eliminate the need for a bonding wire, thereby reducing the ohmic loss and reducing the occurrence of mismatch. I am trying.

[0020]

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

FIG. 1A shows a semi-insulating substrate 1, an RF transceiver circuit 3 and a rectangular patch antenna 6 provided on the semi-insulating substrate 1 in one embodiment of the monolithic antenna module of the present invention. 1 (B) is a partial perspective view showing a portion of FIG. 1 (A), in which a metal layer is formed on the bottom surface of the semi-insulating substrate 1 of FIG. 1 (A) and a recess is formed in the semi-insulating substrate below the rectangular patch antenna. FIG. 1C is a perspective view showing a state in which the metal layer 5 is fixed to the upper surface of the chip carrier 7 and the metal layer 5 on the lower surface of the semi-insulating substrate 1 shown in FIG. It is a perspective view which shows the state made into an antenna module.

As shown in FIG. 1A, an RF transceiver circuit 3 is provided on the upper surface of the semi-insulating substrate 1, and a predetermined frequency is provided on the upper surface of the semi-insulating substrate 1 near the RF transceiver circuit 3. A square patch antenna 6 whose lengths are determined so as to efficiently radiate radio waves in the band is provided, and the RF transmitting / receiving circuit 3 and the square patch antenna 6 are electrically coupled by the coupling section 2. .

The coupling section 2 is usually formed by a transmission line having an appropriate characteristic resistance for impedance matching between the rectangular patch antenna 6 and the RF transmission / reception circuit 3. As shown in FIG. 1 (A), FIG. 1 (B) and FIG. 1 (C), for example, a stub 2A may be provided in the coupling portion 2 and used for such alignment.

In order to use in an ultrahigh frequency band such as a microwave band or a millimeter wave band, as the semi-insulating substrate 1,
For example, gallium arsenide may be used as the material.

The above-mentioned RF transmitting / receiving circuit 3 may be composed of, for example, an integrated circuit having a coplanar structure.

FIG. 3 is a block diagram showing the configuration of an embodiment of the RF transceiver circuit 3. In FIG. 3, a circulator 31 is connected to the rectangular patch antenna 6, and a signal received by the rectangular patch antenna 6 passes through a filter 32 to remove an unnecessary frequency signal and is added to a low noise amplifier 33 to reduce noise. From the amplifier 33, the amplified reception signal is added to the down converter 34. A local oscillation signal having a predetermined frequency is separately added to the down converter 34 from a local oscillator 36.

The down converter 34, for example, converts the input signal into a signal having a frequency difference between the input signal and the frequency of the local oscillation signal output from the local oscillator 36, and outputs the signal to the intermediate frequency amplifier 35.

The intermediate frequency amplifier 35 amplifies this signal and outputs it to the outside.

On the other hand, when a transmission signal having a predetermined frequency is input to the intermediate frequency amplifier 38 from the outside, the intermediate frequency amplifier 38 amplifies this input signal and outputs it to the up converter 39. In the up converter 39, separately,
A local oscillation signal having a predetermined frequency is output from the local oscillator 37 and added. Upconverter 39
Converts the transmission signal output from the intermediate frequency amplifier 38 into a signal having a frequency that is the sum of the frequency of the transmission signal output from the intermediate frequency amplifier 38 and the frequency of the local oscillation signal output from the local oscillator 37. , To the power amplifier 40.

The power amplifier 40 power-amplifies this input signal and outputs it to the circulator 31 via the filter 41.

The circulator 31 outputs the signal output from the filter 41 to the rectangular patch antenna 6.

On the upper surface of the semi-insulating substrate 1 shown in FIG. 1A, a ground conductor 4 is provided so as to surround the RF transceiver circuit 3 and the rectangular patch antenna 6.

On the lower surface of the semi-insulating substrate 1 shown in FIG. 1 (A), a concave portion 8 is formed directly below the rectangular patch antenna 6 so as to face the rectangular patch antenna 6 from the lower surface of the semi-insulating substrate 1.
Furthermore, the metal layer 5 which is a good conductor is provided on the lower surface of the semi-insulating substrate 1 excluding the recess 8.

A chip carrier 7 made of a conductive material such as a metal, the upper surface of which is in contact with the metal layer 5 provided on the lower surface of the semi-insulating substrate 1 shown in FIG. 1B.
Are fixed as shown in FIG. 1C to form a monolithic antenna module.

Between the recess 8 and the chip carrier 7,
A tunnel-shaped cavity 9 having a height H and a uniform cross section orthogonal to the longitudinal direction and the upper surface of the semi-insulating substrate 1 is formed.

This height H is the phase of the radio wave radiated from the square patch antenna 6 and directed downward in FIG. 1 (C), which is reflected by the bottom surface of the cavity 9 and proceeds upward in the square patch antenna 6. And the frequency to be used may be determined so that the phase of the radio wave radiated directly upward from the rectangular patch antenna 6 is in phase.

The thickness of the semi-insulating substrate 1 in the vertical direction (direction perpendicular to the wide surface) should be an appropriate thickness so that the above-mentioned height H can be realized with respect to the wavelength of the radio wave used for transmission and reception. Set it.

The cavity 9 is a free space and its relative permittivity is 1, and the semi-insulating substrate 1 normally has a relative permittivity of 13.
Since the square patch antenna 6 is provided on the upper surface of the semi-insulating substrate 1 and the metal layer is provided on the lower surface of the semi-insulating substrate 1, the square patch antenna 6 is provided between the square patch antenna 6 and the metal layer. 1C, the electrical length between the rectangular patch antenna 6 shown in FIG. 1C and the lower surface of the cavity 9 below which serves as a radio wave reflection surface can be increased.

2 (A), 2 (B) and 2 (C)
Respectively show antenna elements that can be used instead of the rectangular patch antenna shown in FIG. 1 (C). That is, FIG. 2A is a perspective view showing the circular patch antenna 6a, and FIG.
FIG. 2C is a perspective view of the slot antenna 6b, and FIG. 2C is a perspective view of the cross dipole antenna 6c.

RF of these antennas is shown in FIG.
The coupling portion connected to the transmission / reception circuit 3 may have a structure that matches the characteristics of each antenna.

Although the RF transceiver circuit 3 is used in the monolithic antenna module of FIG. 1 (C), for example, when it is used only for reception, the RF transceiver circuit 3 is used.
Instead of the transmission / reception circuit 3, the intermediate frequency amplifier 3 shown in FIG.
5, an RF receiving circuit composed of a down converter 34, a local oscillator 36 and a low noise amplifier 33 is used, and the input side of the low noise amplifier 33 is connected to the square patch antenna 6 via the coupling section 2. The good news is clear.

Further, the square patch shown in FIG.
When the antenna is used only for transmission, for example, the RF transmission circuit including the intermediate frequency amplifier 38, the up converter 39, the local oscillator 37 and the power amplifier 40 shown in FIG. 3 is used instead of the RF transmission / reception circuit 6. Obviously, the output side of the power amplifier 40 may be connected to the coupling section 2.

FIG. 4 (A) is a perspective view showing another embodiment of the monolithic antenna module of the present invention, and FIG. 4 (B) is a sectional view taken along the line AA of FIG. 4 (A). Is.

As shown in FIG. 4B, the semi-insulating substrate 1
In the lower part of the rectangular patch antenna 6, a concave portion 8A is provided so that the size of the upper shape is equal to or larger than the outer shape of the rectangular patch antenna 6 and all of the sides are the semi-insulating substrate 1, and the chip. The carrier 7 and the recess 8A form a cavity 9A.
To form.

The height H between the upper surface of the recess 8A and the upper surface of the chip carrier 7 may be set in the same manner as shown in FIG. 1 (C).

It is obvious that the monolithic antenna module provided with such a cavity 9A operates similarly to the monolithic antenna module shown in FIG.

[0047]

As described above, in the monolithic antenna module of the present invention, the antenna element is provided on the same semi-insulating substrate as the RF transmitter / receiver circuit, so that the connection by the bonding wire is unnecessary. The part has the effect of preventing ohmic loss and performance deterioration due to mismatching.In addition, a recess is provided in the semi-insulating substrate below the antenna element to secure the conductive chip carrier to the semi-insulation described above. By fixing to the lower surface of the conductive substrate, a cavity is formed by the upper surface of this conductive chip carrier and the above-mentioned recess,
It is possible to electrically increase the distance between the above-mentioned antenna element and the reflection surface for reflecting radio waves traveling directly below the antenna element, and as a result, the antenna
The effect is that the frequency bandwidth of the element can be widened.

[Brief description of drawings]

FIG. 1A is a partial perspective view showing a semi-insulating substrate, an RF transmitter / receiver, and a rectangular patch antenna portion of a monolithic antenna module of the present invention. (B) is
It is a partial perspective view which shows the state which provided the recessed part and the metal layer in the semi-insulating board | substrate of (A). (C) is a perspective view of the monolithic antenna module showing a state in which the metal layer provided on the lower surface of the semi-insulating substrate shown in (B) and the upper surface of the chip carrier are fixed to each other.

FIG. 2A is a perspective view of a circular patch antenna that can be used instead of the rectangular patch antenna shown in FIG.
(B) is a perspective view of a slot antenna that can be used instead of the rectangular patch antenna shown in FIG. 1. (C) is a perspective view of a crossed dipole antenna that can be used instead of the rectangular patch antenna shown in FIG. 1.

FIG. 3 is a block diagram showing details of an example of an RF transceiver circuit shown in FIG.

FIG. 4A is a perspective view showing another embodiment of the monolithic antenna module of the present invention. (B) is a sectional view taken along the line AA shown in (A).

FIG. 5 is a perspective view showing an example of a conventional monolithic antenna module of this type.

[Explanation of symbols]

 1 Semi-insulating Substrate 2 Coupling Section 3 RF Transceiver Circuit 4 Ground Conductor 5 Metal Layer 6 Square Patch Antenna 7 Chip Carrier 8 Recess 9 Cavity 2a Stub 6a Circular Patch Antenna 6b Slot Antenna 6c Cross Dipole Antenna 8A Recess 9A Cavity

Claims (8)

[Claims] 1. An RF receiving circuit having a coplanar structure provided near the upper surface of a semi-insulating substrate, and provided on the same surface as the RF receiving circuit on the semi-insulating substrate and electrically coupled to the RF circuit. In a monolithic antenna module including an antenna element, a portion of the semi-insulating substrate immediately below the antenna element is removed by a predetermined depth, and the removed portion is provided on an upper surface of the semi-insulating substrate. A tunnel-shaped recess having a uniform cross-sectional shape, a metal layer provided on the lower surface of the semi-insulating substrate excluding the recess, and a wide outer surface of the metal layer having their upper surfaces in contact and fixed to each other. A monolithic antenna module comprising a conductive chip carrier. 2. An RF receiving circuit having a coplanar structure provided near the upper surface of a semi-insulating substrate, and provided on the same surface as the RF receiving circuit on the semi-insulating substrate and electrically coupled to the RF circuit. In a monolithic antenna module including an antenna element, a portion of the semi-insulating substrate immediately below the antenna element is removed by a predetermined depth, and the removed portion is provided on an upper surface of the semi-insulating substrate. A cross-sectional shape that is parallel to each other is rectangular, and the size of the shape is larger than the outer shape of the monolithic antenna, and a metal layer provided on the lower surface of the semi-insulating substrate excluding the recess, A monolithic antenna module, comprising: a conductive chip carrier having an upper surface in contact with and fixed to a wide outer surface of the metal layer. 3. The monolithic antenna module according to claim 1, further comprising an RF transmission circuit in place of the RF reception circuit. 4. The monolithic antenna module according to claim 1, further comprising an RF transmitter / receiver circuit in place of the RF receiver circuit. 5. The monolithic antenna module according to claim 1, wherein the antenna element is a rectangular or circular patch antenna. 6. The monolithic antenna module according to claim 3, wherein the antenna element is a rectangular or circular patch antenna. 7. The antenna element is a slot
The monolithic structure according to claim 1 or 2, which is an antenna.
Antenna module. 8. The antenna element is a slot
The monolithic device according to claim 3 or 4, which is an antenna.
Antenna module.