JPH0482405A - Triplet plane antenna - Google Patents

Abstract

PURPOSE:To improve efficiency by specifying position relationship among a radiant element and a slot, shape, and size. CONSTITUTION:The radiant element 4 and the slot 3 are arranged at an equal interval in two directions intersecting orthogonally to each other, respectively, and also, an arranging interval (d) is set at a value of 0.85-0.93 times the free spatial wavelength lambda0 of the center frequency of a frequency band area in use. Also, by forming the shape of the slot 3 in a square whose one side is set at the length of 0.48-0.65 times the wavelength lambda0, the unrequired radiation of a feed line can be suppressed by arranging the phases of waves radiated from neighboring slots, and also, the efficiency of an antenna can be further neightened by employing a parasitic element.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a triplate type planar antenna used for transmitting and receiving microwave bands.

(Prior Art) Planar antennas that replace parabolic antennas have been developed as antennas used in the microwave band.

As such a planar antenna, Fig. 5(a) and (
A microstrip line as shown in b) is used as a feed line 5, a patch-shaped radiating element 4 is provided at the tip thereof, and both the feed line 5 and the radiating element 4 are formed on the surface of the dielectric 2,
There is a microstrip patch antenna in which a ground conductor 1 is provided on the back side of the dielectric 2. In actual use, a large number of such bunch-shaped radiating elements 4 are provided, and in order to perform phase matching, impedance matching, etc., the length of the feed line 5, the branch position, and line width are adjusted, and a large number of radiating elements 4 are used. By arranging the feed line 5 between the 4 and 4, an array is formed.

However, since the feed line 5 is exposed on the radiation surface, unnecessary radiation is generated from branching and bending points, degrading the radiation characteristics.

As a means of increasing the antenna efficiency of such a planar antenna, as shown in FIGS. 5(C) and (d), a ground conductor 1 and a radiating element 4 which is superimposed on the surface of this ground conductor 1 and a radiating element 4 is placed on the surface thereof. A dielectric 2 on which an antenna circuit including a feed line 5 is formed, a dielectric 21 stacked on the side of the dielectric 2 on which the antenna circuit is formed, and a dielectric 21 stacked on the surface of the dielectric 21 and directly above the radiating element 4. A triplate-type planar antenna consisting of a ground conductor 11 with slots 3 in the corresponding locations is disclosed in 1988 Institute of Electronics, Information and Communication Engineers National Conference Proceedings B-39r) Windowed Microstrip Antenna J Powered by Ribrate Lines has been done.

In such a triplate type planar antenna, the feed line 5 is arranged in the space between the two ground conductors 1 and 11, and as shown in Fig. 5(e), the feed line 5 is arranged in the space between the two ground conductors 1 and 11. It is known to suppress unnecessary radiation.

(It is a problem to be solved by the invention) Although such a conventional triplate-type planar antenna is effective in suppressing unnecessary radiation from the feed line, the area of the slot 3 is small, so the stopping radiation efficiency is reduced, and the Compared to the antenna shown in FIGS. 5(a) and 5(b) without the conductor 11, the gain is 1 to 4 dB lower. Also, if the area of the slot 3 is increased, the effect of suppressing the unnecessary radiation of the feed line described above is low. As a result, the gain of the antenna decreased.

An object of the present invention is to provide a triplate type planar antenna with excellent gain and high antenna efficiency.

(Means for Solving the Problems) In order to investigate the influence of adjacent slots, the present inventors
As shown in FIG. 2(a), sample A has a slot 3 directly above one radiating element 4 and a slot 31 in a position parallel to the slot 3; The relationship between the distance d between the slot 3 and the slot 31 or 32 and the radiation gain was measured using a sample B having a slot 3 directly above it and a slot 32 diagonally extending from the slot 3.

As a result, as shown in FIG. 2(C), when the distance d between slot 3 and slot 3I or 32 is 0.72 to 0.93 times the wavelength λe of the center frequency of the frequency band to be used, We found that the gain was higher than with slot 3 alone.

This means that the phase of the radio waves radiated from slot 3 and the phase of the radio waves radiated from slot 31 or 32 are separated by an interval d.
When it is 0.72 to 0.93 times the wavelength λe of the center frequency of the frequency band to be used, they are aligned, and in other cases, the opposite is true, and it is considered that the gain is affected.

The present inventors also determined the dimensions of the slot 3 based on the second
As a result of measurement as shown in Figure (d), the upper line of the graph is the characteristic when the number of radiating elements is 384, and the lower line is the characteristic when the number of radiating elements is converted to 1. Approximately 0 for the wavelength λe of the center frequency of the frequency band
．． It was found that there is a peak at 59 times.

Furthermore, when using the structure shown in FIGS. 4(a) and 4(b) using the parasitic element 6 directly above the radiating element 4, the second
As shown in Figure (e), it was also discovered that among the characteristics of the size and gain of the slot 3, when the size of the slot 3 is smaller, the gain is higher than when there is no parasitic element 6.

The present invention has been made based on the above knowledge, and the triplate type planar antenna of the present invention, as shown in FIGS. A dielectric 2 which is stacked on top and has an antenna circuit including a radiating element 4 and a feed line 5 formed on its surface, a dielectric 21 which is stacked on the side of the dielectric 2 on which the antenna circuit is formed, and a surface of the dielectric 21. In a triplate type planar antenna consisting of a ground conductor 11 that is stacked on top of the ground conductor 11 and has a slot 3 located directly above the radiating element 4, the radiating element 4 and the slot 3 are arranged equally in two directions perpendicular to each other. The free space wavelength λ of the center frequency of the frequency band to be used is determined by the arrangement interval d in the two directions. It is characterized by being 0.85 to 0.93 times larger.

Here, from the above experiment, the arrangement interval d is the free space wavelength λ of the center frequency of the frequency band to be used.

It was found that the gain becomes high when the gain is 0.72 to 0.93 times larger than The influence of not only the adjacent slot 31 but also the slot 32 must be considered, and the reason why the gain increases by considering the influence of the eight surrounding slots for one slot 3 is as follows.
It was in the range of 0.82 to 0.93 times.

Further, in the triplate type planar antenna of the present invention, the length of one side of the slot 3 is 0.48 to 0.65 times the free space wavelength λe of the center frequency of the frequency band to be used. It is characterized by the use of a square shape.

At this time, the shape of the slot 3 is set to 0.48 to 0.48 to
It may also be a circle whose diameter is 0.65 times the length.

(Blank below C) Furthermore, the triplate planar antenna of the present invention is
As shown in FIGS. 4(a) and 4(b), in the above-described antenna, a ground conductor 11 having the slot 3
, and a parasitic element 6 formed on the surface of the dielectric 22 at a position directly above the radiating element 4 and the slot 3.

At this time, the radiating elements 4 may be arranged in pairs.

As the radiating element of the present invention, in the case of linearly polarized waves, the radiating element
Circular or rectangular batch-shaped radiating elements as shown in Figures (a) and (b) can be used.

In the case of circularly polarized waves, a two-point feeding radiating element consisting of a circular or rectangular patch-shaped radiating element connected to a feeding line 901 with different phases as shown in Fig. 3(c) and (d) is used. Alternatively, a single-point feeding type radiating element with a so-called perturbation in which the vertical-to-horizontal ratio is changed has the shapes shown in Figure 3 (e) and (r). can be used.

The shape of the parasitic element may be any shape generally used for a radiating element, such as a circle or a square as shown in FIGS. 4(c) and 4(d).

(Function) As mentioned above, the triplate type planar antenna of the present invention has the feature of suppressing unnecessary radiation of the conventional feed line by having an arrangement that allows the phases of radio waves radiated from adjacent slots to be aligned. The antenna efficiency can be further increased by employing a slot size with high antenna efficiency and a parasitic element that increases efficiency.

Example 1 As shown in FIGS. 1(a) and (b), an aluminum plate with a thickness of 3 mm and a size of 140 mm x 140 mm was used as the ground conductor 1, and as the dielectric material 2 overlaid on the surface of the ground conductor I. , a polyethylene foam with a thickness of 2 mm and a dielectric constant of 1.1 is used, and a substrate is used on the surface of which a copper foil is bonded to a polyethylene film with a thickness of 25 pm, and a radiating element 4 and a feed line 5 are mounted on the substrate. An antenna circuit including the antenna circuit is formed by etching unnecessary parts of the copper foil, and a dielectric 21 made of the same material as the dielectric 2 and having a thickness of 2 mm is used on the surface of the antenna circuit. A ground fi body 11 with a slot 3 provided at a location directly above the radiating element 4 on the surface of 21 has a thickness of 0.5 mm.
An aluminum plate of mm was used.

At this time, the number of radiating elements 4 and slots 3 is! 6, the radiating elements 4 and slots 3 are arranged at equal intervals in two directions perpendicular to each other, and the arrangement interval d in the two directions is set to the free space of 1l-85GH2, which is the center frequency of the frequency band to be used. Wavelength λ* 22-5
mm is 0°89 times, the shape of slot 3 is square, and the length of the - side is 0.51λe, so it is 13mm.
It became.

The gain of this antenna was 19.5 dB, and when converted to one radiating element, the gain was about 3 dB higher than when there was one slot per radiating element.

Example 2 24 antennas prepared in Example 17 were arranged and shown in Fig. 1(d).
), as a result of using an array antenna with a feeding point in the center, the gain of this antenna is 33.2 dB, and when converted to one radiating element, the gain is 33.2 dB. The gain was about 3-3dB higher than that.

Example 3 The antenna was constructed in the same manner as in Example 1, except that the shape of the slot 3 was a circle whose diameter was 0.5 l times the free space wavelength λe of the center frequency of the frequency band to be used. It was created. The results were almost the same as in Example 1.

Example 4 Using the antenna prepared in Example 1, a ground conductor 1 having a slot 3 was constructed as shown in FIGS. 4(a) and (b).
1 with a thickness of 2 mm as a dielectric 22.
A parasitic element 6 is provided on the surface of the dielectric 22 at a position directly above the radiating element 4 and the slot 3, using the same material as the radiating element 4, and having the same size as the radiating element 4. , using a substrate made of copper foil laminated to a polyethylene film with a thickness of 25I1m, and removing unnecessary parts by etching.

As a result, the same gain as in Example 1 was obtained.

(Effects of the Invention) As explained above, the present invention can suppress unnecessary radiation from the feed line by using a high-gain planar antenna while maintaining the same characteristics as the conventional triplate planar antenna. were able to provide.

[Brief explanation of the drawing]

FIG. 1(a) is a top view showing one embodiment of the present invention, FIG. 1(b) is a sectional view taken along line AA in FIG. 1(a), and 1st WJ (c
) is a schematic top view for explaining the present invention in detail, FIG. 1(d) is a top view showing another embodiment of the present invention, and FIG.
) and (b) are top views of the sample for detailed explanation of the present invention, FIG. 2(c) is a diagram showing the relationship between slot spacing and radiation gain for detailed explanation of the present invention, and FIG. Figure (c
1) is a diagram showing the relationship between slot size and radiation gain to explain the present invention in detail, and FIG. Diagrams for comparing characteristics, Figures 3(a) to (f) are top views showing the shape of the radiating element that can be used in the present invention, and Figure 4(a) is a diagram showing another example of the present invention. A sectional view shown in FIG. 4 (b
) is a top view of Fig. 4(a), Fig. 4(C) and (d)
is a top view showing the shape of a parasitic element that can be used in the present invention,
FIG. 5(a) is a top view showing a conventional example, FIG. 5(b) is a sectional view taken along the line AA in FIG. 5(a), and FIG. 5(c) is a top view showing another conventional example. FIG. 5(d) is a sectional view taken along the line AA in FIG. 5(c), and FIG. 5(e) is a sectional view for explaining the characteristics of the conventional example. Explanation of symbols 1.11. Ground conductor 2, 21.22-dielectric 3.31
．． 32. Slot 4, radiating element 5. Power supply line 6.1! #Engraving of the power supply facility drawing (no changes to the content) (a) (b) Figure power supply point (n) Figure (c) Figure (mushi) (b) Slot Bi Sochi (d/l,) (c ) Figure (ci) (Hatake) (b) (c) (d) Figure slot size (4/ζ) (e) (b) (d) Figure (a) (c) (e) Procedural amendment (Method) % formula % 2. Name of the invention: Tri-plate planar antenna 3. Relationship with the person making the amendment: Patent applicant address: 2-1-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo.
Name (445) Hitachi Chemical Co., Ltd. Representative: Ryoji Yokoyama 4, Agent address: 2-1-1-6 Nishi-Shinjuku, Shinjuku-ku, Tokyo, Drawing subject to amendment 7, Contents of amendment

Claims (1)

[Claims] 1. A ground conductor (1), and a dielectric material overlaid on the surface of the ground conductor (1) and on which an antenna circuit including a radiating element (4) and a feed line (5) is formed. (2), a dielectric (21) stacked on the side of the dielectric (2) on which the antenna circuit is formed,
Further, the radiating element (
4), in which the radiating element (4) and the slot (3) are arranged in two directions orthogonal to each other. They are arranged at equal intervals, and the arrangement interval d in the two directions is 0.85 to 0.0.
A triplate type planar antenna characterized by a 93x magnification. 2. The shape of the slot (3) should be 0.48 to 0.48 to the free space wavelength λ_e of the center frequency of the frequency band to be used.
2. The triplate planar antenna according to claim 1, wherein a square shape is used, the length of one side of which is 0.65 times the length of the square. 3. The shape of the slot (3) is 0.48 to 0.48 to the free space wavelength λ_e of the center frequency of the frequency band to be used.
The triplate type planar antenna according to claim 1, characterized in that a circular shape is used whose diameter is 0.65 times the length. 4. A dielectric material (22) superimposed on the surface of the ground conductor (11) having the slot (3), and a dielectric material (22) located directly above the radiating element (4) and the slot (3). )
4. The triplate planar antenna according to claim 1, further comprising a parasitic element (6) formed on the surface of the triple plate antenna. 5. The triplate type planar antenna according to any one of claims 1 to 4, wherein the radiating elements (4) are arranged in pairs.