JPH07307614A - Slot connection type microstrip antenna - Google Patents

Abstract

PURPOSE:To facilitate impedance control by adjusting the length of the slot of a first conductive plate so as to match the impedance for which a slot connection type microstrip antenna is viewed from the input end of a power feeding line. CONSTITUTION:When transmission microwave signals are inputted to a microstrip line for feeding power, the electromagnetic waves of the transmission microwave signals radiated from the microstrip line excite a radiation conductor 1 through rectangular slots 5s, 4s and 3s. At this time, the electromagnetic waves are radiated towards free space in a direction vertical to the surface of the radiation conductor 1. In this case, since the impedance is adjusted by using a ground semiconductor plate 4 thinner than ground conductor plates 3 and 5, the impedance is matched more easily than the thick ground conductor plates. Thus, in the resonance frequency of this microstrip antenna, the impedance viewed from the input end of the microstrip line for feeding the power is set to prescribed line impedance and the impedance is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slot coupling type microstrip antenna.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view of a conventional slot-coupled microstrip antenna, which is taken along line C- of FIG.
FIG. 5 is a vertical sectional view taken along the line C ′, and FIG.
FIG. 6 is a vertical cross-sectional view taken along the line D ′, and FIG.
3 is a plan view of the slot-coupled microstrip antenna of FIG.

As shown in FIGS. 4 to 6, a rectangular slot 10s having a predetermined comparatively thick thickness and formed in the central portion so as to penetrate in the thickness direction is provided to support the entire antenna. An MMIC semiconductor substrate 6 (hereinafter referred to as semiconductor substrate 6) having a microwave monolithic integrated circuit (hereinafter referred to as MMIC) mounted on the lower surface of the antenna supporting ground conductor plate 10 (hereinafter referred to as ground conductor plate 10) is provided. ) Is bonded using die bonding or the like, while the antenna dielectric substrate 2 is attached to the upper surface of the ground conductor plate 10.
(Hereinafter, referred to as the dielectric substrate 2) is adhered using an adhesive. Further, a strip conductor 7 is formed on the lower surface of the semiconductor substrate 6 so as to be orthogonal to the longitudinal direction of the rectangular slot 10s. Here, the strip conductor 7 and the ground conductor plate 1
And 0 form a power feeding microstrip line. Furthermore, on the upper surface of the dielectric substrate 2, the rectangular radiating conductor 1 is formed such that each side thereof is parallel to each side of the rectangular slot 10s.

In the conventional example configured as described above, by adjusting the length of the rectangular slot 10s in the longitudinal direction, at the resonance frequency of the microstrip antenna, from the input end of the feeding microstrip line to the antenna. It is possible to set the impedance at the time of seeing to a predetermined line impedance and adjust so as to perform impedance matching (hereinafter referred to as impedance adjustment). Further, since the ground conductor plate 10 having a relatively large thickness is used, the ground conductor plate 10 is
The semiconductor substrate 6 on which C is mounted can be firmly supported and can be used as a heat dissipation plate that efficiently dissipates the heat generated by the MMIC.

[0005]

In the conventional example described above, it is not easy to form the rectangular slot 10s in the ground conductor plate 10 having a relatively large thickness, and the rectangular slot 10s has been conventionally used to adjust the impedance. Only an antenna having a shape in which a uniform length in the longitudinal direction is held over the thickness direction of the ground conductor plate 10 is known, and therefore, a uniform length with respect to the ground conductor plate 10 having a thickness of sub-millimeter order is known. Rectangular slot 10s having a length in the direction
In order to obtain the above, an expensive method such as laser processing was required. Further, in order to adjust the impedance, it is necessary to prepare several ground conductor plates 10 corresponding to the rectangular slots 10s having several lengths in the longitudinal direction, which causes further difficulty. Further, since the semiconductor substrate 6 is adhered to the ground conductor plate 10 by die bonding or the like, it is difficult to peel off the semiconductor substrate 6 on which the MMIC is mounted without damage once it is adhered.
When C is damaged, there is a problem that a large loss is incurred.

The object of the present invention is to solve the above problems and to easily adjust the impedance of the antenna viewed from the input end to a predetermined impedance of the feed line as compared with the conventional example, and at a low cost. It is to provide a slot-coupled microstrip antenna.

[0007]

According to a first aspect of the present invention, there is provided a slot-coupling type microstrip antenna in which a ground conductor plate is sandwiched between dielectric substrates and radiated onto the dielectric substrate. While forming a conductor, a feeding line is formed on the substrate on the side opposite to the grounding conductor plate, and is formed on the grounding conductor plate immediately below the radiation conductor so as to intersect with the feeding line. In a slot-coupled microstrip antenna comprising a slot for electromagnetically coupling the radiation conductor with the radiation conductor, the ground conductor plate has a first ground conductor plate having the slot, and the substrate having the slot. And a second ground conductor plate for supporting the second ground conductor plate, the slot of the first ground conductor plate is equal to the length of the slot of the second ground conductor plate. The length of the slot of the first ground conductor plate is adjusted so that the impedance of the slot-coupled microstrip antenna seen from the input end of the feed line is the feed line. It is formed to adjust the impedance so as to match the impedance of the.

A slot-coupled microstrip antenna according to a second aspect is the slot-coupled microstrip antenna according to the first aspect, wherein the ground conductor plate further comprises the second ground conductor plate and the substrate. It is characterized in that it is provided with a third grounding conductor plate which is sandwiched between them and has a slot longer than the slot of the first grounding conductor plate and which supports the substrate. Further, the slot-coupled microstrip antenna according to claim 3 is the slot-coupled microstrip antenna according to claim 1 or 2, wherein the first ground conductor plate is the dielectric substrate and the second ground conductor plate. It is characterized by being sandwiched between and.

Still further, the slot-coupled microstrip antenna according to claim 4 is the same as claim 1, 2 or 3.
In the slot-coupled microstrip antenna described above, at least a portion of the inner peripheral surface of the slot of the ground conductor plate except the inner peripheral surface of the slot of the first ground conductor plate has a tapered cross section. Is formed in. Further, the slot-coupled microstrip antenna according to claim 5 is the slot-coupled microstrip antenna according to claim 1, 2 or 3, wherein the inner peripheral surface of the ground conductor plate has a stepwise cross section. Is formed in.

Further, the slot-coupled microstrip antenna according to claim 6 is the slot-coupled microstrip antenna according to claim 1, wherein the ground conductor plate further includes the dielectric substrate and the first ground conductor plate. And a fourth ground conductor plate having a slot longer than that of the first ground conductor plate and supporting the dielectric substrate. Furthermore, the slot-coupled microstrip antenna according to claim 7 is the slot-coupled microstrip antenna according to any one of claims 1 to 6, wherein the substrate is a semiconductor substrate, and a microwave monolithic integrated circuit is used. It is characterized by having a circuit.

[0011]

In the slot-coupled microstrip antenna configured as described above, when the transmission microwave signal is input to the power feeding line, the electromagnetic waves of the transmission microwave signal are transmitted from the power feeding line to the first and the second electromagnetic waves. The radiation conductor is excited through the slot of the second ground conductor plate.
At this time, the electromagnetic wave is radiated toward the free space in a direction perpendicular to the radiation conductor.

In the slot-coupled microstrip antenna, the slot of the first ground conductor plate is
The slot-coupled micro-chip has a length shorter than that of the slot of the second ground conductor plate, and is adjusted from the input end of the feed line by adjusting the length of the slot of the first ground conductor plate. It is formed to adjust the impedance of the strip antenna so that it matches the impedance of the feed line.

[0013]

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

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
FIG. 4 is a vertical cross-sectional view of the slot-coupled microstrip antenna that is the embodiment of FIG. 3, and is a vertical cross-sectional view taken along the line AA ′ of FIG. 3, and FIG. 2 is a vertical cross-sectional view taken along the line BB ′ of FIG. 3. FIG. 3 is a plan view of the slot-coupled microstrip antenna of FIGS. 1 and 2. 1 to 3, the same components as those in FIGS. 4 to 6 are designated by the same reference numerals.

The slot-coupled microstrip antenna according to the first embodiment is, as shown in FIGS.
In place of the conventional ground conductor plate 10 shown in FIGS. 4 to 6, the following three layers of ground conductor plates 3, 4, and 5 are provided. (A) An antenna dielectric substrate supporting ground conductor plate 3 (hereinafter, referred to as ground conductor plate 3) for supporting the antenna dielectric substrate 2. (B) At the resonance frequency of the microstrip antenna, an impedance adjusting ground conductor plate for impedance matching so that the impedance when the antenna is viewed from the input end of the feeding microstrip line is set to a predetermined line impedance. 4 (hereinafter referred to as the ground conductor plate 4). (C) MMIC for supporting the semiconductor substrate 6
A ground conductor plate 5 for supporting a semiconductor substrate (hereinafter referred to as the ground conductor plate 5).

As shown in FIGS. 1 to 3, a rectangular slot having a predetermined relatively large thickness for supporting the antenna dielectric substrate 2 and formed in the central portion so as to penetrate in the thickness direction. The antenna dielectric substrate 2 is formed on the upper surface of the ground conductor plate 3 having 3s so as to be fixed by being bonded with an adhesive or the like. Then, the rectangular radiation conductor 1 is formed in the center of the antenna dielectric substrate 2. On the other hand, on the lower surface of the ground conductor plate 5 having a predetermined relatively thick thickness for supporting the MMIC semiconductor substrate 6 and having a rectangular slot 5s formed so as to penetrate in the thickness direction in the central portion, M with or without
The MIC semiconductor substrate 6 is formed so as to be fixed by performing die bonding or the like. Then, on the lower surface of the semiconductor substrate 6, the strip conductor 7 is formed so as to be orthogonal to the longitudinal direction of the rectangular slot 5s. Here, the strip conductor 7 and the ground conductor plate 5 constitute a feeding microstrip line.

Further, between the ground conductor plate 3 and the ground conductor plate 5, a rectangular slot 4s having a thickness smaller than that of each of the ground conductor plates 3 and 5 and penetrating in the thickness direction is formed in the central portion. First, the impedance adjusting ground conductor plate 4 is sandwiched without using an adhesive or the like without being fixed. Here, the radiation conductor 1 has a rectangular slot 3 on each side thereof.
It is formed right above each rectangular slot 3s, 4s, 5s so that it is parallel to each side of the rectangular s, 4s, 5s and its center coincides with the center of each rectangular of the rectangular slots 3s, 4s, 5s. It

The length and width in the longitudinal direction of the rectangular slot 10s of the conventional example are the same in the ground conductor plate 10 on which it is formed, but in the present embodiment, the rectangular slot 3s,
The lengths and widths of the 4s and 5s in the longitudinal direction are set to be different from each other. Here, the length of the rectangular slot 4s of the impedance adjusting ground conductor plate 4 in the longitudinal direction needs to be set shorter than the length of the rectangular slots 3s and 5s of the other ground conductor plates 3 and 5 in the longitudinal direction. There is. The setting of the lengths and widths of the rectangular slots 3s, 4s, 5s will be described later in detail in <Size of rectangular slot>.

As described above, the above-mentioned impedance adjustment is performed in a state where the ground conductor plate 4 is sandwiched between the ground conductor plates 3 and 5, but is not fixed with an adhesive or the like. That is, one of the plurality of ground conductor plates 4 in which the rectangular slots 4s having various longitudinal lengths or various sizes are formed is selectively ground conductor plates 3 and 5.
Or the size of the rectangular slot 4s of one ground conductor plate 4 is changed by cutting the inner peripheral surface of the slot.
The length in the longitudinal direction of the can be adjusted. Thereby, at the resonance frequency of the microstrip antenna, the impedance when the antenna is viewed from the input end of the feeding microstrip line can be set to a predetermined line impedance and adjusted so as to perform impedance matching. After the impedance adjustment is completed, the ground conductor plate 4 whose size of the rectangular slot 4 has been adjusted is sandwiched between the ground conductor plates 3 and 5 so that they can be fixed with an adhesive or the like.

In the slot-coupled microstrip antenna configured as described above, when a transmission microwave signal is input to the feeding microstrip line,
The electromagnetic waves of the transmission microwave signal emitted from the microstrip line are rectangular slots 5s, 4s, 3s.
The radiation conductor 1 is excited via. At this time, the electromagnetic wave is emitted toward the free space in a direction perpendicular to the surface of the radiation conductor 1.

In the above embodiments, impedance adjustment can be performed by using the ground conductor plate 4 having a smaller thickness than the ground conductor plates 3 and 5, so that a comparison is made when a thicker ground conductor plate is used. The impedance can be adjusted inexpensively and easily. In addition, the semiconductor substrate 6 having the MMIC mounted or built-in is not peeled off, and the ground conductor plate 5
The rectangular slot 4s of the ground conductor plate 4 fixed on the top
The impedance adjustment can be performed by changing only the size of. As a result, the impedance adjusting ground conductor plate 4 is simply connected to the ground conductor plate 3, without damaging or destroying the MMIC.
Impedance adjustment can be performed in a manner that is easier to handle and in a state of actual use simply by sandwiching between the five. In other words, according to the present embodiment, the impedance adjustment 1 is located immediately below the dielectric substrate 2 on which the radiation conductor 1 is formed among the three layers of ground conductor plates 3, 4, 5.
This is possible only with the ground conductor plate 4 in one layer, and in the ground conductor plates 3 and 5 in the other two layers, the lengths of the rectangular slots 3s and 5s are fixed.

Further, in the present embodiment, since the ground conductor plates 3, 4 and 5 of three layers are used to form a relatively thick ground conductor plate, the semiconductor substrate 6 mounting or incorporating the MMIC is firmly supported. In addition, the ground conductor plates 3, 4, 5 can be used as a heat dissipation plate that efficiently dissipates the heat generated in the MMIC.

<Second Embodiment> FIG. 7 is a first vertical sectional view of a slot-coupled microstrip antenna according to a second embodiment of the present invention. The first embodiment shown in FIG. It is a figure corresponding to the 1st longitudinal sectional view of. In addition, FIG.
FIG. 9 is a second vertical cross-sectional view of the slot-coupled microstrip antenna of the second embodiment, corresponding to the second vertical cross-sectional view of the first embodiment of FIG. 2.

In the second embodiment, as shown in FIGS. 7 and 8, the following three layers of ground conductor plates are formed between the dielectric substrate 2 and the semiconductor substrate 6 in this order from the top. It is characterized by that. (A) Impedance adjusting ground conductor plate for impedance matching so that the impedance when the antenna is viewed from the input end of the feeding microstrip line is set to a predetermined line impedance at the resonance frequency of the microstrip antenna. 4. (B) First M for supporting the MMIC semiconductor substrate 6
Ground conductor plate 5a for supporting MIC semiconductor substrate (hereinafter referred to as first ground conductor plate 5a). (C) Second M for supporting MMIC semiconductor substrate 6
Ground conductor plate 5b for supporting MIC semiconductor substrate (hereinafter referred to as second ground conductor plate 5b).

Compared to the first embodiment, the second embodiment does not have the ground conductor plate 3 and has a two-layer structure of the ground conductor plate 5, and the ground conductor plates 4 and 4. 5a,
The size of the rectangular slot formed in 5b changes in a staircase shape in its cross section. This rectangular slot 4s, 5a
The lengths and widths of the s and 5bs in the longitudinal direction are different from each other as follows. Here, the length of the rectangular slot 4s of the impedance adjusting ground conductor plate 4 in the longitudinal direction is different from that of the other ground conductor plate 5a. , 5b need to be set shorter than the lengths of the rectangular slots 5as, 5bs in the longitudinal direction, and the lengths and widths of the rectangular slots 4s, 5as, 5bs in the longitudinal direction are set as described later in detail.

In the second embodiment, the rectangular slot 4
The sizes of s, 5as, and 5bs are set as follows.

[Formula 1] Ws1 <Ws2 <Ws3

## EQU00002 ## Ls3 <Ls1 <Ls2 where Ws1 is the rectangular slot 5bs of the ground conductor plate 5b.
And Ws2 is the rectangular slot 5 of the ground conductor plate 5a.
The width is as, and Ws3 is the width of the rectangular slot 4s of the ground conductor plate 4. Further, Ls1 is the length of the rectangular slot 5bs of the ground conductor plate 5b in the longitudinal direction, Ls2 is the length of the rectangular slot 5as of the ground conductor plate 5a in the longitudinal direction, and Ls3 is the rectangular slot 4s of the ground conductor plate 4. Is the length in the longitudinal direction.

The second embodiment described above operates similarly to the first embodiment, and the rectangular slot 4 after the ground conductor plate 4 is operated.
Impedance adjustment can be performed by adjusting the size of s, and has the same effect as the first embodiment. That is, according to the present embodiment, the impedance adjustment is performed by the radiation conductor 1 of the three-layer ground conductor plates 4, 5a, 5b.
This is possible only with the ground conductor plate 4 of one layer located immediately below the dielectric substrate 2 in which the rectangular substrate 5 is formed, and the lengths of the rectangular slots 5as, 5bs in the ground conductor plates 5a, 5b of the other two layers are fixed. is there. Further, before impedance adjustment, the semiconductor substrate 6 and the two ground conductor plates 5a and 5b are fixed with an adhesive or the like, but the ground conductor plate 4 is placed between the dielectric substrate 2 and the ground conductor plate 5a. It is sandwiched so as to be adhesively fixed. After adjusting the impedance, the ground conductor plate 4 is adhesively fixed between the dielectric substrate 2 and the ground conductor plate 5a using an adhesive or the like.

<Third Embodiment> FIG. 9 is a first vertical sectional view of a slot-coupled microstrip antenna according to a third embodiment of the present invention. The first embodiment shown in FIG. It is a figure corresponding to the 1st longitudinal sectional view of. In addition, FIG.
FIG. 8B is a second vertical cross-sectional view of the slot-coupled microstrip antenna of the third embodiment, corresponding to the second vertical cross-sectional view of the first embodiment of FIG.

In the third embodiment, as shown in FIGS. 9 and 10, the following two layers of ground conductor plates are formed between the dielectric substrate 2 and the semiconductor substrate 6 in this order from the top. It is characterized by that. (A) Impedance adjusting ground conductor plate for impedance matching so that the impedance when the antenna is viewed from the input end of the feeding microstrip line is set to a predetermined line impedance at the resonance frequency of the microstrip antenna. 4. (B) MMIC for supporting the MMIC semiconductor substrate 6
Grounding conductor plate 5c for supporting a semiconductor substrate (hereinafter, grounding conductor plate 5
It is called c. ). Here, in particular, the third embodiment is characterized in that the rectangular slot 5cs formed in the ground conductor plate 5c is formed so that its cross-sectional shape changes in a tapered shape.

In the third embodiment, as compared with the first embodiment, there is no ground conductor plate 3 and there are two ground conductor plates.
The ground conductor plates 4 and 5c have a layered structure, and the rectangular slot formed in the ground conductor plate 5c has a tapered cross-sectional shape. Here, the rectangular slot 5cs may have a tapered shape in a part in the thickness direction of the ground conductor plate 5c and a linear shape in the other part.

The lengths and widths of the rectangular slots 4 and 5c in the longitudinal direction are different from each other as follows. Here, the length of the rectangular slot 4s of the impedance adjusting ground conductor plate 4 in the longitudinal direction is: It is necessary to set shorter than the maximum length in the longitudinal direction of the rectangular slot 5cs of the other ground conductor plate 5c, and the length and width in the longitudinal direction of the rectangular slots 4s and 5cs are set as described later in detail.

In the third embodiment, the rectangular slot 4
The sizes of s and 5cs are set as follows.

(3) (maximum width of rectangular slot 5cs) <Ws3

[Formula 4] Ls3 <(maximum length of rectangular slot 5cs)

In the above third embodiment, the same operation as in the first embodiment is performed, and the rectangular slot 4 after the ground conductor plate 4 is operated.
Impedance adjustment can be performed by adjusting the size of s, and has the same effect as the first embodiment. That is, according to the present embodiment, the impedance can be adjusted only in the one-layer ground conductor plate 4, which is located immediately below the dielectric substrate 2 on which the radiation conductor 1 is formed, of the two-layer ground conductor plates 4 and 5c. And the length of the rectangular slot 5cs in the ground conductor plate 5c of the other layer is fixed. Further, before the impedance adjustment, the semiconductor substrate 6 and the ground conductor plate 5c are fixed with an adhesive or the like.
Is sandwiched between the dielectric substrate 2 and the ground conductor plate 5c so as to be adhesively fixed. And after impedance adjustment,
The ground conductor plate 4 is bonded and fixed between the dielectric substrate 2 and the ground conductor plate 5c with an adhesive or the like.

In the third embodiment, the rectangular slot 5cs of the ground conductor plate 5 has a tapered cross section, for the following reason. The size of the rectangular slot 4s of the impedance adjusting ground conductor plate 4 needs to be adjusted by using a more accurate processing method such as laser processing, but the rectangle of the ground conductor plate 5 that does not require accuracy. This is because the inner peripheral surface of the rectangular slot 5cs may be processed by side etching using a simple wet etching method for the slot 5cs. This makes it possible to perform sharper machining, and to simplify the machining process as a whole compared to performing highly accurate machining on all the inner peripheral surfaces of the rectangular slot. There is a unique effect that can be.

Incidentally, the ground conductor plate 5 in the second embodiment.
At least a part of the inner peripheral surfaces of the rectangular slots 5as, 5bs of a, 5b may be formed such that the cross section thereof has a tapered shape, as in the third embodiment.

<Size of Rectangular Slot> The inventor of the present invention prototyped the slot-coupled microstrip antenna of the second embodiment using the following parameter values and made various measurements to determine the size of the rectangular slot. Considered the setting. (A) Length of one side of radiation conductor 1 Lp = Wp = 3.5 m
m; (b) Ws3 = 0.4 mm; (c) Ws2 = 0.25 mm; (d) Ws1 = 0.2 mm; (e) Ls3 = 2.4 mm; (f) Ls2 = 5.2 mm; (g) Ls1 = 3.5 mm.

From the experiments conducted by the present inventor, the following has been found regarding the setting of the size of the rectangular slot. Conventionally, the impedance adjustment is performed by adjusting the length of the rectangular slot in the longitudinal direction, but when a plurality of ground conductor plates are provided as in the embodiment of the present invention. Of the rectangular slots formed in each ground conductor plate, the one having the shortest length in the longitudinal direction is suitable for use in impedance adjustment. This is because the change in length of the shortest rectangular slot in each layer of the ground conductor plate is reflected most strongly in the impedance. "The length L of a rectangular slot when it is composed only of a ground conductor plate having the same thickness and composed of a single layer known in the prior art.
ground conductor plate 5a equal to or longer than "s0",
When the rectangular slots 5as and 5bs on 5b are set, impedance adjustment can be performed by setting the length Ls0 equal to or shorter than the length Ls0. Therefore, the lengths of the rectangular slots of the ground conductor plates other than the impedance adjusting ground conductor plate 4 need to be set longer than the length Ls0. If you do not set it like this,
An electromagnetic field radiated from the power feeding microstrip line toward the radiating conductor 1 is a rectangular slot in which the length of the rectangular slots of the ground conductor plates other than the impedance adjusting ground conductor plate 4 is set shorter than the length Ls0. This is because the ground conductor plate is cut off and does not reach the radiation conductor 1 so that the radiation conductor 1 is not excited.

Further, the impedance adjusting ground conductor plate 4
The installation position of is a layer immediately below the antenna dielectric substrate 2 and closest thereto (see the second and third embodiments).
Alternatively, a ground conductor plate 3 supporting the antenna dielectric substrate 2
It is preferable that the layer is immediately below and closest to it (see the first embodiment). This is because the ground conductor plates 5, 5a, 5b, 5c supporting the MMIC semiconductor substrate 6 are the same as those described in the section of the prior art.
This is because it is extremely difficult to adjust the sizes of the rectangular slots a, 5b, and 5c, which may damage the MMIC.

Further, in addition to the above, in consideration of the operating principle of the microstrip antenna, if analogy as a cavity that has been widely performed from the past is performed, the antenna conductor substrate sandwiched between the radiation conductor and the ground conductor plate is It is considered that a good antenna operation can be obtained by operating as a cavity in the region including the fringing portion from the radiation conductor. Here, the length of the rectangular slot of the first grounding conductor plate in the layer immediately below and closest to the dielectric substrate 2 is longer than the length of the rectangular slot of the second grounding conductor plate in the next layer adjacent thereto. When set, the cavity operates depending not only on the rectangular slot of the first grounding conductor plate but also on the rectangular slot portion of the second grounding conductor plate, which may hinder good operation as the cavity. It is highly likely. For this reason, it is preferable that the impedance adjusting ground conductor plate 4 is provided at the closest position immediately below the dielectric substrate 2 as shown in the second or third embodiment.

The widths Ws1 and Ws2 of the rectangular slot do not necessarily have to be set wider than the width Ws3. This is derived from the known fact that when the width of the rectangular slot is within a predetermined width, it does not become a dominant parameter for the slot-coupled microstrip antenna.

<Modification> In the above embodiments, the rectangular slots 3s, 4s, 5s, 5as, 5bs, 5c.
However, the present invention is not limited to this, and may have, for example, a circular or elliptical slot. In the above embodiment, the strip conductor 7 has the slots 3s, 4s,
Although it is formed so as to be orthogonal to 5s, 5as, 5bs, and 5cs, the present invention is not limited to this, and may be formed so as to intersect at an angle exceeding at least 0 degrees.

In the above embodiments, the ground conductor plate 3,
4,5, 5a, 5b, 5c may be laminated with a multilayer ground conductor plate.

In the above first embodiment, three ground conductor plates 3, 4, 5 are provided, but the present invention is not limited to this, and a ground conductor plate having more than three layers may be provided. Good. In the above second embodiment, three ground conductor plates 4, 5a,
However, the present invention is not limited to this, and may include a ground conductor plate having more than three layers. In the third embodiment described above, the two ground conductor plates 4 and 5c are provided, but the present invention is not limited to this, and the ground conductor plates of more than two layers may be provided. In other words, the present invention may be a ground conductor plate having a structure of two or more layers including at least two ground conductor plates.

Although the semiconductor substrate 6 is used in the above embodiments, the present invention is not limited to this, and a dielectric substrate may be used instead of this.

In the above embodiments, one slot-coupling type microstrip antenna is described, but the present invention is not limited to this, and a plurality of slot-coupling type microstrip antennas are formed at a predetermined interval. An array antenna may be configured. In particular, in this embodiment, since the ground conductor plates 3, 4, 5, 5a, 5b, 5c having a relatively large thickness are used for the entire antenna, the array antenna can be easily formed. It can be used as a communication antenna.

[0046]

As described in detail above, according to the present invention, a ground conductor plate is sandwiched between dielectric substrates to form a radiation conductor on the dielectric substrate, while the ground conductor is formed. A feeding line is formed on the substrate on the side opposite to the plate, and the grounding conductor plate immediately below the radiation conductor is formed so as to intersect with the feeding line, and the feeding line and the radiation conductor are electromagnetically coupled. In a slot-coupled microstrip antenna including slots to be coupled, the ground conductor plate has a first ground conductor plate having the slot, and a second ground conductor plate having the slot and supporting the substrate. And at least two layers of the ground conductor plates are laminated, and the slot of the first ground conductor plate has a length shorter than the length of the slot of the second ground conductor plate. Ground conductor plate slot By adjusting the length and the impedance looking into the impedance of the slot coupled microstrip antenna from the input end of the feed line is formed to the impedance adjusted to match the impedance of the feed line.

Therefore, the impedance can be adjusted by using, for example, the first grounding conductor plate having a relatively thin thickness, so that the impedance can be adjusted easily and inexpensively as compared with the case where a thicker grounding conductor plate is used. can do. Also, the impedance adjustment is performed by not changing the size of the slot of the first grounding conductor plate in a state of being fixed on another second grounding conductor plate without removing the substrate on which the MMIC is mounted or built-in. It can be performed.
As a result, the MMIC is not damaged and destroyed, and the first impedance adjusting ground conductor plate is simply sandwiched between the dielectric substrate and the substrate for better handling. The impedance adjustment can be performed by a simple method and in a state of actual use.

Further, according to the present invention, since a relatively thick ground conductor plate is formed by using at least two layers of ground conductor plates, it is possible to firmly support the substrate on which the MMIC is mounted or incorporated. , The ground conductor plate is the MM
It can be used as a heat dissipation plate that efficiently dissipates the heat generated by the IC.

[Brief description of drawings]

FIG. 1 is a first vertical sectional view of a slot-coupled microstrip antenna that is a first embodiment according to the present invention, and is a vertical sectional view taken along the line AA ′ of FIG.

FIG. 2 is a second vertical sectional view taken along the line BB ′ of FIG.

3 is a plan view of the slot-coupled microstrip antenna of FIGS. 1 and 2. FIG.

FIG. 4 is a first vertical sectional view of a conventional slot-coupled microstrip antenna, which is a vertical sectional view taken along the line CC ′ of FIG.

FIG. 5 is a second vertical cross-sectional view taken along the line DD ′ of FIG.

6 is a plan view of the slot-coupled microstrip antenna of FIGS. 4 and 5. FIG.

7 is a first vertical sectional view of a slot-coupled microstrip antenna according to a second embodiment of the present invention and corresponds to the first vertical sectional view of the first embodiment of FIG. It is a figure.

8 is a second vertical cross-sectional view of the slot-coupled microstrip antenna of the second embodiment, corresponding to the second vertical cross-sectional view of the first embodiment of FIG.

9 is a first vertical sectional view of a slot-coupled microstrip antenna according to a third embodiment of the present invention, which corresponds to the first vertical sectional view of the first embodiment shown in FIG. 1. FIG. It is a figure.

10 is a second vertical sectional view of the slot-coupled microstrip antenna of the third embodiment, and FIG.
It is a figure corresponding to the 2nd longitudinal cross-sectional view of the 1st Example of.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Radiating conductor, 2 ... Antenna dielectric substrate, 3 ... Antenna dielectric substrate supporting ground conductor plate, 4 ... Impedance adjusting ground conductor plate, 5, 5a, 5b, 5c ... MMIC semiconductor substrate supporting ground conductor plate, 6 ... MMIC semiconductor substrate, 7 ... Strip conductor, 3s, 4s, 5s, 5as, 5bs, 5cs ... Rectangular slot.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Isamu Chiba 5 Seiraya, Seika-cho, Soraku-gun, Kyoto Pref. 5 Hiratani, Arai Optical Radio Communications Research Institute, Inc. (72) Inventor Yoshio Karasawa Soraku, Kyoto Prefecture Gunma Seika-cho, Osamu Osamu, Osamu Osamu, 5 Mihiraya, AT Optical Optical Communication Laboratory

Claims (7)

[Claims] 1. A ground conductor plate is sandwiched between dielectric substrates to form a radiation conductor on the dielectric substrate.
A feed line is formed on the substrate on the side opposite to the ground conductor plate, and is formed on the ground conductor plate immediately below the radiation conductor so as to intersect with the feed line, and the feed line and the radiation conductor are connected to each other. In a slot-coupled microstrip antenna including a slot that is electromagnetically coupled, the ground conductor plate has a first ground conductor plate having the slot, and a second ground conductor plate having the slot and supporting the substrate. And at least two layers of ground conductor plates including a ground conductor plate, wherein the slot of the first ground conductor plate has a length shorter than the length of the slot of the second ground conductor plate, The first
By adjusting the length of the slot of the ground conductor plate, the impedance viewed from the input end of the feed line to the impedance of the slot-coupled microstrip antenna is adjusted to match the impedance of the feed line. A slot-coupled microstrip antenna characterized in that it is formed for the purpose. 2. The ground conductor plate is further sandwiched between the second ground conductor plate and the substrate, has a slot longer than the slot of the first ground conductor plate, and has the substrate The slot-coupled microstrip antenna according to claim 1, further comprising a third grounding conductor plate that supports the same. 3. The slot-coupled microstrip according to claim 1, wherein the first ground conductor plate is sandwiched between the dielectric substrate and the second ground conductor plate. antenna. 4. At least a part of the inner peripheral surface of the slot of the grounding conductor plate excluding the inner peripheral surface of the slot of the first grounding conductor plate is formed so that its cross section has a tapered shape. The slot-coupled microstrip antenna according to claim 1, 2, or 3. 5. The slot-coupled microstrip antenna according to claim 1, wherein the inner peripheral surface of the ground conductor plate is formed so that its cross section has a step shape. 6. The ground conductor plate is further sandwiched between the dielectric substrate and the first ground conductor plate, and the first ground conductor plate is disposed between the dielectric substrate and the first ground conductor plate.
2. The slot-coupled microstrip antenna according to claim 1, further comprising a fourth grounding conductor plate having a slot longer than that of the grounding conductor plate and supporting the dielectric substrate. 7. The slot-coupled microstrip antenna according to claim 1, wherein the substrate is a semiconductor substrate and has a microwave monolithic integrated circuit mounted thereon.