JPH01290302A - Microstrip antenna - Google Patents

Abstract

PURPOSE:To realize a microstrip antenna with a broad band by providing a 2nd ground conductor connecting a radiation conductor and a ground conductor intermittently to the inside of a 1st ground conductor. CONSTITUTION:A radiation conductor 12 provided with a prescribed shape of opening 14 is provided against a ground conductor 11 and the circumferential part of the radiation conductor 12 is connected to the ground conductor 11 by using the 1st ground conductor 15B. Moreover, the 2nd ground conductor 15A connecting intermittently the radiation conductor 12 to the ground conductor 11 is provided at the inside of the 1st ground conductor 15B. The 2nd ground conductor 15A is arranged in the inside of the 1st ground conductor 15B in this way to obtain a microstrip antenna 10 having a frequency band depending on the radiation conductor 12, the ground conductor 11, the 1st ground conductor 15B, the radiation conductor 12, the ground conductor 11 and the 2nd ground conductor 15A. Thus, the frequency band of the antenna is widened more than a conventional band.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

Industrial field of application B Overview of the invention C Conventional technology (Figure 15) D Problems to be solved by the invention (Figures 15 and 16)
Figure) Means to solve problem E (Figure 1) 2 Effects (1st
Figure) G Example (Figures 1 to 14) (G1) First Example (Figures 1 to 3) (G2) Second
Example (Fig. 4) (G3) Third example (Fig. 5) (G4) Other examples (Figs. 6 to 14) H Effects of the invention A Industrial application field The present invention is Regarding microstrip antennas, the present invention is particularly applicable to microstrip antennas with a wide frequency band.

B. Summary of the Invention The present invention provides a microstrip antenna.
By providing a second ground conductor inside the ground conductor, the frequency band of the microstrip antenna can be widened.

C. Prior Art Conventionally, a microstrip antenna of this type has been proposed in which the operating frequency and directivity can be freely selected (Japanese Patent Application No. 62-33259).
No. 4).

That is, in FIG. 15, 1 indicates a microstrip antenna as a whole, and a radiation conductor 2 made of a circular flat plate conductor is arranged to face a ground conductor 4 with a dielectric 3 in between.

The peripheral edge of the radiation conductor 2 is connected to the peripheral edge of the ground conductor 4 via the ground conductor 5, so that the radiation conductor 2, together with the earth conductor 4 and the ground conductor 5, forms a cavity.

Therefore, the microwaves fed via the feed line 6 and the connector 7 resonate at a frequency determined by the size of the cavity and the dielectric constant of the dielectric 3.

Furthermore, the radiation conductor 2 is provided with a circular opening 2A in the center, and the microwaves resonated in the cavity are transmitted to the opening 2A.
It is designed to radiate from A.

Therefore, by setting the size of the cavity and the dielectric constant of the dielectric material 3 to desired values, a microstrip antenna with a desired frequency can be obtained, and the size of the opening 2A can be selected to a desired size. By doing so, the I stoichiometry determined by the size of the opening 2A can be obtained.

Problems to be Solved by the Invention Incidentally, in this type of microstrip antenna, microwaves are resonated in a cavity and radiated, so as shown in Fig. 16, the frequency band is generally narrow. There's a problem.

Therefore, there is a problem in that it is difficult to practically apply it to communication equipment that requires a wide frequency band.

Furthermore, the wavelength band in which this type of microstrip antenna is used is an extremely short frequency band, so if there is even a slight deviation in dimensions during antenna manufacturing, the center frequency of the microstrip antenna will change significantly. .

Therefore, when the frequency band is narrow like this, the microstrip antenna must be manufactured with high dimensional accuracy, which makes manufacturing difficult.

The present invention has been made in consideration of the above points, and aims to propose a microstrip antenna with a wide frequency band.

E Means for Solving the Problem In order to solve this problem, the present invention includes a ground conductor 11, a radiation conductor 12 disposed opposite to the ground conductor 11, and provided with an opening 14 of a predetermined shape, A first grounding conductor 15B grounds the peripheral edge of the radiating conductor 12 to the grounding conductor 11;
1 and a second ground conductor 15A that is intermittently grounded to the ground conductor 1.

If the second grounding conductor 15B is arranged inside the first grounding conductor 15A, the radiation conductor 12, the grounding conductor 11 and the first grounding conductor 15A are A microstrip antenna 10 having a frequency band determined by the second ground conductor 15B can be obtained, and the frequency band of the microstrip antenna can be correspondingly widened.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

(G1) First Embodiment In FIG. 1, 10 indicates a microstrip antenna as a whole, and the ground conductor 1 is made of a flat plate conductor in the shape of a quadrilateral shadow.
1 and a radiation conductor 12 are arranged opposite to each other with a dielectric 13 in between.

The radiation conductor 12 has a circular opening 1 with a radius of a value a.
4 in the center, and the outer radii b1 and b! of the opening 14 are A plurality of through holes 5A and 15B connecting the ground conductor 11 and the radiation conductor 12 are provided at predetermined intervals on the circumference of the ground conductor 11 and the radiation conductor 12, so that the ground conductor 11 and the radiation conductor 12 can be b! The connection is made intermittently at the

Further, in the grounding conductor 11 and the radiation conductor 12, a power supply line is connected to a predetermined position on the inner circumferential side of the through hole 15A via a connector, thereby connecting the grounding conductor 11 and the radiation conductor 12 with a micro It is designed to be powered by waves.

Therefore, in the microstrip antenna 10, there is a first annular region surrounded by the ground conductor 11, the radiation conductor 12, and the through hole 15A, and a first annular region surrounded by the ground conductor 11, the radiation conductor 12, and the through hole 15B. 2 annular regions are formed, and M! of the first and second annular regions are formed. The microwaves resonated at a are radiated from the opening 14.

Therefore, as shown in FIG. 2, the through hole 15B provided at the radius 1, together with the ground conductor 11 and the radiation conductor 12, constitutes a second cavity in which microwaves of a predetermined frequency f resonate. The arrangement interval is selected so that

Furthermore, a through hole 15 provided at a position with a radius of
At A, the frequency f! with the ground conductor 11 and the radiating conductor 2. so as to constitute a first cavity in which microwaves having a predetermined frequency f higher than that resonate, and a frequency f8
When the microwave of the frequency f is supplied, the microwave of the frequency f can resonate in the second cavity composed of the through hole 15B1, the ground conductor 11, and the radiation conductor 12,
The arrangement interval is selected.

Therefore, through hole 15A1 ground conductor 11 and radiation conductor 1
In the first cavity composed of the through hole 15B, the ground conductor 11, and the radiation conductor 12, the reflection coefficient becomes the smallest at the frequency f1, as shown by the curve L1. In the cavity, curve L2
As shown, the reflection coefficient becomes the smallest at the frequency f, and thereby the reflection coefficient of the entire microstrip antenna 10 can be made the smallest at the frequencies f and f.

Therefore, as shown in FIG. 3, if the frequencies f and ft are set close to the desired frequency r0,
A microstrip antenna 1o with a wide band can be obtained by using the frequency f as the center frequency.

Therefore, it is possible to obtain a microstrip antenna that is easy to manufacture, and it can be applied to communication equipment that requires a wide frequency band.

Therefore, the radii b1 and b for arranging the through holes 15A and 15B! are selected as follows.

That is, assuming that the dielectric constant of the dielectric 13 is ε1 and the propagation velocity of the electromagnetic wave is C, the following equation (Ja(k
+a)) ' ・y*(k+b+)-JII(kIJ
) ・ (Y-(Ja))' -0・・・・・・
(2) The arrangement position Rh + of the through hole 15A is selected so that the relational expression expressed as follows is satisfied at the frequency f.

Here, J, I, and Y are the n-th order Bessel function and Neumann function, respectively, and rJ, (kla month' and (Y
-(k+a))' represents the differential expression.

Further, n is the order n when the operating mode of the microstrip antenna 1° is expressed as Ta+t mode.

Similarly, to the variable expressed by the following relational expression! Using the following formula (J, (k
ta)) ' ・Ya(kzbz)-J, 1(ktb
t) ・(Y-(kta))'-Q・・・・・・
(4) The arrangement position bt of the through hole 15B is selected so that the relational expression expressed as follows is satisfied at the frequency ft.

Incidentally, in this embodiment, a through hole 15B is arranged at an intermediate position between adjacent through holes 15A.

Furthermore, the radius a of the aperture 14 is selected so as to obtain the desired directivity, thereby making it possible to obtain a microstrip antenna with a wide band and desired directivity at the center frequency f.

(Thus, the through hole i5B forms a first grounding conductor that grounds the peripheral edge of the radiation conductor 12 to the ground conductor 11, whereas the through hole 15A forms the radiation conductor inside the first ground conductor.) 12 constitutes a second grounding conductor that is intermittently grounded to the grounding conductor 11.

In the above configuration, the microstrip antenna 10
The microwave of frequency r fed to the microwave resonates in the second cavity composed of the through hole i5B provided at the radius s, the ground conductor 11, and the radiation conductor 12, and is emitted from the opening 14. radiated.

On the other hand, microwaves with frequency f have a radius of °
The radiation resonates in the first cavity formed by the through hole 15A provided at the position of , the ground conductor 11, and the radiation conductor 12, and is radiated from the opening 14.

Therefore, the reflection coefficient can be lowered between frequencies f and f2.

According to the above configuration, the second grounding conductor for intermittently grounding the radiation conductor 12 to the grounding conductor 11 is placed inside the first grounding conductor composed of the through-hole 15A.
By configuring with
5B, the microwave with the frequency determined by the radiation conductor 12 and the ground conductor 11 can be radiated, and thus the microstrip antenna 10 with a wide band can be obtained.

(G2) Second Embodiment In FIG. 4, in which parts corresponding to those in FIG. Instead of arranging the through holes 15B, the first and second ground conductors are formed by arranging every two through holes 15A and 15B.

According to the configuration shown in FIG. 4, even if every two through holes 15A and 15B are arranged, the first
The same effects as in the embodiment can be obtained.

(G3) Third Embodiment In FIG. 5, 21 indicates a microstrip antenna as a whole, and a plurality of through holes 15G are formed at the inner radius of the through hole 15A, and the first and second cavities are connected to each other. In addition to the through hole 15C2, a third cavity composed of the radiation conductor 12 and the ground conductor 11 is formed.

According to the configuration shown in FIG. 5, by forming the third cavity in addition to the first and second cavities, it is possible to obtain a micro-microwave with a wider band than the first and second embodiments. You can get a strip antenna.

(G4) Other Embodiments In the above-mentioned embodiments, a case was described in which the first ground conductor was formed by intermittently connecting the radiation conductor and the ground conductor with through holes. The conductor is not limited to this. For example, the radiation conductor and the dielectric material may be cut into a disc shape with a radius bt, and the side surface of the dielectric material may be plated to form a first ground conductor that connects the radiation conductor and the ground conductor. Various connection methods can be widely applied, such as when applying a conductive paste to the side surface of the dielectric to form a first ground conductor.

Furthermore, in the above embodiment, the present invention was applied to a microstrip antenna in which the ground conductor 11 and the radiation conductor 12 made of flat plate conductors were arranged in parallel. It is not limited to parallel, but can be deformed in various ways.

That is, as shown in cross section in FIGS. 6 to 11,
The spacing between the ground thickness body 11 and the radiation conductor 12 is set to different values at the center and the periphery of the microstrip antenna.

For example, in FIG. 6, the ground conductor 11 made of a flat plate conductor and the radiation conductor 12A having a protruding central portion are connected by the first ground conductor 16 so that the distance between the openings 14 is increased.

On the other hand, in FIG. 7, the radiation conductor 12 made of a flat plate conductor is connected to the ground conductor 11A with a protruding central portion by the first ground conductor 16, so that the gap at the opening 14 is increased. .

Furthermore, in FIGS. 8 and 9, the ground conductor IIA and the radiation conductor 12A, each having a protruding central portion, are connected by a ground conductor 16, so that the gap at the opening 14 is increased.

On the other hand, in FIG. 10, a grounding conductor 11B having a flat surface facing the opening 14 and a protruding center is connected to a radiation conductor 12A having a protruding center. so that it becomes larger.

On the contrary, in FIG. 11, the grounding conductor 11C and the radiation conductor 12B, each having a concave center, are connected by the first grounding conductor 16 so that the distance between them is narrowed at the opening 14.

In this way, the frequency band of the microstrip antenna can be widened compared to the case where the ground conductor 11 and the radiation conductor 12 are arranged in parallel. By forming the second ground conductor with a hole, a microstrip antenna with an even wider band can be obtained.

Furthermore, in the above embodiment, the disk-shaped dielectric 13
However, the shape of the dielectric is not limited to this, and the portion opposing the opening 14 may be omitted.

In this way, the amount of dielectric material used can be reduced and a microstrip antenna that is correspondingly lighter can be obtained.

Furthermore, in the above embodiment, the dielectric material 1 having a dielectric constant ε
Although the case where the dielectric 3 is disposed between the ground conductor 11 and the radiation conductor 12 has been described, the present invention is not limited to this, and the dielectric 13 may be omitted.

In this way, an air layer having a dielectric constant of 1 can be obtained between the ground conductor 11 and the radiation conductor 12, and the overall configuration can be simplified accordingly.

Furthermore, instead of a dielectric material having a -like dielectric constant, dielectric materials having different dielectric constants may be arranged in the center portion and the peripheral portion of the microstrip antenna.

That is, as shown in FIG. 12, between the ground conductor 11 and the radiation conductor 12, which are made of a flat plate body, the dielectric constant is 8.
□, trx and ε. Annular dielectrics 13A and 13B
and 13C, the dielectric constant on the inner circumferential side of the microstrip antenna is made larger than that on the outer circumferential side.

On the other hand, in FIG. 13, the dielectric constant C
A dielectric material 13A having a dielectric constant of 6□ and a dielectric material 13E having a dielectric constant of 6□ and C0 are arranged in a layered manner so that the thickness of the dielectric material 13D becomes thinner as it approaches the opening 14. This makes the dielectric constant on the inner circumferential side larger than that on the outer circumferential side.

Furthermore, in FIG. 14, the dielectric material 13F is arranged such that the dielectric constant gradually decreases from the inner circumferential side to the outer circumferential side, so that the dielectric constant on the inner circumferential side is larger than that on the outer circumferential side. I will make it happen.

In this way, the frequency band of the microstrip antenna can be widened compared to the case where the dielectric material 13 having a -like permittivity is arranged between the ground conductor 11 and the radiation conductor 12, and the first By forming a second ground conductor with a through hole inside the ground conductor 16, a microstrip antenna with an even wider band can be obtained.

Furthermore, in the above-mentioned embodiment, a case was described in which the first, second, and third grounding conductors were configured by arranging through holes in a circular shape with respect to a circular opening. The arrangement shape of the through holes is not limited to this, and can be variously modified as necessary, such as arranging the through holes in a quadrilateral shape or a hexagonal shape, for example.

Furthermore, in this case, only a portion of the first, second, and third ground conductors may be changed from a circular shape or the like to a desired arrangement shape.

Furthermore, in the above-mentioned embodiment, a case was described in which microwaves were fed to the microstrip antenna using a feeder line, but the microwave feeding method is not limited to this.
For example, various power supply methods such as strip lines can be widely applied.

H Effects of the Invention As described above, according to the present invention, by configuring the second grounding conductor that connects the radiation conductor and the grounding conductor intermittently inside the first grounding conductor, the first grounding conductor , a microwave with a frequency determined by the radiating conductor and the ground conductor, and a frequency determined by the second ground conductor, the radiating conductor, and the ground conductor, and thus a microstrip antenna with a wide band can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a microstrip antenna according to an embodiment of the present invention, FIGS. 2 and 3 are characteristic curve diagrams for explaining its operation, and FIG. 4 is a perspective view showing a second embodiment thereof. 5 is a perspective view showing the third embodiment, and FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, and FIG. 11 are other configurations of the radiation conductor and the ground conductor. 12th cross-sectional view showing
13 and 14 are cross-sectional views showing other configurations of the dielectric, FIG. 15 is a perspective view showing a conventional microstrip antenna, and FIG. 16 is a characteristic curve diagram for explaining its operation. . 1.10.20.21... Microstrip antenna, 2.12.12A, 12B... Radiation conductor, 3.13.13A, 13B, 13C, 13E. 13F...Dielectric, 4.11, IIA, IIB
, 11C...Ground conductor, 5.15A, 15B, 1
6... Ground conductor.

Claims (1)

[Scope of Claims] A grounding conductor; a radiating conductor disposed opposite to the grounding conductor and having an opening in a predetermined shape; and a first grounding conductor that grounds a peripheral portion of the radiating conductor to the grounding conductor. and a second grounding conductor that intermittently grounds the radiation conductor to the grounding conductor inside the first grounding conductor.