JPH09162631A - Antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna having electrical characteristics of a feeding wave guide type antenna and capable of being small in size, light in weight and simple in production by forming a metallic plating film at the parts excluding the radio wave radiation surface of a dielectric that is connected to a feeding connector. SOLUTION: A metallic plating films 11 is formed at the parts excluding the radio wave radiation surface 12 of a dielectric 10 that is connected to a feeding connector 14a. The feeding electrode of the connector 14a protruding over an optional surface of the dielectric 10 is adhered to the film 11 via a conductive resin material. Thus the screw attachment structure is not needed for the feeding electrode, and a dielectric antenna of a monocock structure requires no metallic casing. Then the size and weight of the antenna can be reduced together with its facilitated production. It is preferable to decide the shape of the dielectric 10 conforming to the shape of the internal space of a feeding wave guide type antenna that has a ridge in its internal space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectangular or circular feeding waveguide type having a space inside and a radio wave radiation opening surface which is an opening of the space and to which a power feeding connector is connected. The present invention relates to an antenna that has the same characteristics as an antenna and that is configured by using a dielectric.

[0002] In recent years, feeding waveguide type antennas such as horn antennas are used in various electronic equipment systems such as microwaves. Especially, in the electronic equipment system due to the demand of wide band of use frequency band and high density mounting. High performance, miniaturization, and weight reduction are required.

For this reason, the feed waveguide type antenna is an antenna that is very often used in the microwave region above 1 GHz, has a high gain, and has an excellent impedance characteristic over a wide band among aperture antennas. Therefore, wide band use is possible. Moreover, as another advantage, theoretical calculation gives a result very close to the actual one. Therefore, there is a demand for an antenna using a dielectric material that has the electrical characteristics of this feeding waveguide type antenna and that achieves higher performance, smaller size, and lighter weight.

[0004]

2. Description of the Related Art FIG. 18 shows a QUAD-RIDGE having four ridges, which is a conventional feeding waveguide type antenna.
A perspective view showing the configuration of the D (quad-ridge) type waveguide antenna 1, and FIG. 19 is a sectional view taken along the line AA ′ in FIG. 18, which will be described.

In FIG. 18 and FIG. 19, reference numeral 2 is a rectangular parallelepiped antenna metal housing 3a, 3b, 3c, 3d having one opening surface and a space of four side surfaces inside.
Are ridges fixed to the four side surfaces inside the metal housing 2.

Reference numerals 1a and 1b denote connectors fixed to the outside of the metal housing 2, and the coated power supply electrodes 5a and 5b inside the connectors 1a and 1b have the metal housing 2 of the metal housing 2 as shown in FIG. One ridge 3 facing the top and bottom inside
It penetrates through d and 3c and is inserted into the other ridges 3b and 3a, and the inserted portion is fixed with a screw 6.

Reference numeral 4 indicates an external space, and 7 indicates a free space inside the antenna. The ridges 3a to 3d are for matching with the external space 4, that is, for improving the impedance characteristic so that radio waves are appropriately radiated.

In such a structure, the input signal is input from the connectors 1a and 1b provided on the metal housing 2 and transmitted to the power supply electrodes 5a and 5b. After that, the power is radiated to the free space 7 inside the antenna and the power supply electrodes 5a,
Power is supplied to the connection part of the screw 6 (2 places) of 5b, and the ridge 3
It transmits a to 3d and is radiated from the opening surface to the free space 4.

Further, in order to obtain a required antenna gain or to improve the impedance characteristic, a horn shown by reference numeral 8 in FIG. 20 may be fixed on the aperture plane. Regarding the antenna 1, the cross section of the waveguide is gradually widened to have a required opening, and the wavefront at the opening surface becomes a curved surface, causing a deviation from the flat surface. Therefore, in order to make this deviation a small value with respect to the wavelength, there is a case where the horn 8 having an appropriately small horn opening angle is used.

In the above-described conventional antenna structure, the metal casing 2 has a high-pass waveguide structure, and in the internal shape (inside the waveguide structure), the wavelength of the lower frequency band of the frequency band used. λ limits the transmission mode in the waveguide and determines the shape. The following equation shows the relationship between the wavelength λ [m] in free space and the operating frequency f [Hz].

Λ = c / f where c is the speed of light 3 × 10 ⁸ [m / s]. For example, the frequency band used by the antenna is 5 GHz to 10 G
When designing an antenna of Hz, the internal shape (inside the waveguide structure) corresponds to the wavelength λ near 5 GHz of the low frequency side frequency.

[0012]

By the way, in the above-mentioned conventional feed waveguide type antenna, when a wide band antenna and a low band antenna are used, the outer shape is enlarged, the weight is increased, and the processing accuracy is high. There was a problem that it had to be.

In the processing and surface treatment techniques, brass is often used because of its workability when actually manufacturing a waveguide. Further, since the surface roughness is important for the waveguide circuit, the low transmission loss line, etc., it is directly related to the characteristics as well as the processing accuracy. Generally, the surface roughness is the skin depth δ (1 GHz
A fraction of several μm is required in the vicinity.

Δ = √ (ρ / π · f · μ) = 1 / 34.4√ (ρ · λ ₀ / μ _* ) [mm] where ρ: specific resistance [Ω · m], μ = μ _*・ Μ ₀ : Permeability (μ ₀ = 4π × 10 ^-7 H / m), μ _* : Relative permeability, f:
Frequency [Hz], λ ₀ : wavelength [m].

For example, in the case of copper, ρ = 10 ⁻⁷ /5.8
Since [Ω · m] and μ _* = 1, δ _cu = 6.64 / √f [cm].

Further, since the usable frequency has a high-pass waveguide structure, the usable frequency depends on the wavelength λ of the lower frequency side, and once the waveguide shape is determined, the usable frequency is fixed. there were.

Further, in the case of the feeding waveguide type antenna 1 described above, the structure of the waveguide ridges 3a to 3d, the fixing structure of the feeding electrodes 5a and 5b by the screw 6, that is, the internal structure of the waveguide is complicated. There was a problem that became.

The present invention has been made in view of the above points, and has the electric characteristics of a feed waveguide type antenna, and enables miniaturization, weight reduction, and simplification of manufacturing. An object is to provide an antenna using a dielectric that can be used.

[0019]

FIG. 1 shows the principle of the present invention. The antenna shown in FIG. 1 has a connector 1 for power feeding.
In addition to the radio wave radiation surface 12 of the dielectric 10 to which the 4a is connected, a metal plating film 11 is applied, and the dielectric 10
The power feeding electrode of the connector 14a protruding on an arbitrary surface of the above is configured to be bonded to the metal plating film 11 with a conductive resin material.

In such a structure, a screw structure for attaching a power feeding electrode unlike the conventional antenna is not required, and a dielectric antenna having a monocoque structure which does not require a metal casing is provided, so that the manufacturing is facilitated, and the size / weight is reduced. Can be realized.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a perspective view showing the structure of the dielectric antenna according to the first embodiment of the present invention. In this figure, parts corresponding to the parts of the conventional example shown in FIG. 18 are designated by the same reference numerals, and description thereof will be omitted.

In the dielectric antenna 9 shown in FIG. 2, 1
0 is a rectangular parallelepiped dielectric, 15a to 15d are dielectrics 10.
It is a ridge provided by forming elongated recesses along the longitudinal direction on the four side surfaces that circulate, and in the figure, only the ridges on two sides are shown.

Reference numeral 11 is a metal plating film of about several μm,
It is provided on all surfaces except the radiation surface 12 on which the four ridges 15a to 15d of the dielectric 10 contact and the insertion portion of the power feeding connector fixedly inserted in the ridges 15a and 15b.

When the dielectric antenna 9 having such a structure is produced, first, the ridges 3a to 3d of the conventional feeding waveguide type antenna 1 similar to that shown in FIG. 18 and shown in FIG.
The inside of the frame mold 13 having the same structure as the waveguide provided with is filled with a dielectric and solidified.

After that, the frame mold 13 is removed to obtain the dielectric 10 shown in FIG. Then, as shown in FIG. 5, the radiation surface 1 with which the four ridges 15a and 15b of the dielectric 10 are in contact
2 and all surfaces except the power supply electrode insertion portion (not shown) are plated with a metal having a thickness of several μm to form a metal plated film 11
To form

Then, the connectors 14a, 14 shown in FIG.
2 is shown in FIG. 7 in which the power supply electrodes 21a and 21b are shown in FIG.
Is attached to the ridges 15a and 15b so as to project to the ridge on the opposite side as shown in the sectional view taken along line BB 'of FIG.

As a result, the dielectric antenna 9 of the monocoque structure does not require the screw mounting structure for the feeding electrode as in the conventional example and does not require the metal casing. In such a configuration, the signals supplied to the connectors 14a and 14b are transmitted to the ridges 15a to 15d of the dielectric body 10,
It is radiated to the free space from the radiation surface 12 of the dielectric 10.

Further, the dielectric antenna 9 having such a monocoque structure is used as the conventional feeding waveguide type antenna 1.
Can be smaller than. This is more than that of the conventional feed waveguide type antenna 1 because of the relationship among the wavelength λ, the speed of light c, the frequency f, the propagation velocity coefficient v in the dielectric 10 and the permittivity ε of the dielectric 10, as shown in the following equation. The size is 1 / √ε.

Λ = (c / f) v v = 1 / √ε, where ε: permittivity of dielectric (ε = 1 in free space),
v: Propagation velocity coefficient in the dielectric layer.

In the conventional antenna 1, the shape is substantially restricted by the wavelength λ in free space (dielectric constant ε = 1), but in the dielectric antenna 9 of the first embodiment, the dielectric constant ε is larger than 1. By using the body 10, it is possible to shorten the wavelength suitable for the purpose.

For example, when the dielectric 10 having a dielectric constant ε = 10 is used, the wavelength λ is v = 1 / √ε = 1 / from the propagation velocity coefficient v in the dielectric layer according to the above equation. √10 ≅⅓.

Therefore, the external shape of the conventional rectangular parallelepiped feed waveguide type antenna 1 is approximately 1 in each of the X, Y and Z directions.
The dielectric antenna 9 shortened by / 3 can be configured. In addition, the monocoque structure of the dielectric body 10 and the structure in which the power supply electrodes 21a and 21b can be adhesively connected with the conductive resin material 22 eliminates the need for high-precision processing accuracy as in the conventional case, and thus the influence of power supply is reduced. It is possible to easily realize a power supply electrode fixing structure that does not receive.

Further, since the metal casing is not used and the entire size can be reduced, the weight can be reduced. Further, since the frame body 13 can be used to form the dielectric body 10, which is the main body, the manufacturing process is facilitated, and mass production of products with good processing accuracy can be realized.

However, the weight reduction of the whole depends on not only the size of the whole but also the dielectric constant of the dielectric 10. FIG.
It is a figure which shows an example of the weight characteristic of the dielectric antenna with respect to a dielectric constant. In FIG. 8, it is assumed that the specific gravity of the metal housing 2 of the conventional antenna 1 is 9 g / cm ³ and the specific gravity of the dielectric 10 of the dielectric antenna 9 is 6 g / cm ^3, and the horizontal axis is the dielectric constant ε of the dielectric 10. The vertical axis is represented by the weight ratio (times) with respect to the conventional antenna 1.

From this characteristic, the dielectric constant of the dielectric 10 is ε = 2.5.
In the case of, the weight is about 1/10, and when the dielectric constant ε = 10, the weight is about 1/100. That is,
Significant weight reduction is possible.

Besides, as shown in FIG. 9, if a dielectric lens 19 covering the radiation surface 12 is mounted, impedance matching characteristics and antenna gain can be improved. The dielectric lens 19 corresponds to the horn 8 shown in FIG. 20 of the conventional example, and includes the dielectric 10 of the antenna body.
It has a dielectric constant lower than that of.

The reflection loss [d
B] and an impedance matching characteristic diagram in which the frequency [GHz] is plotted on the horizontal axis, and the effects when the dielectric lens 19 is mounted will be described with reference to these. However, it is assumed that the dielectric constant ε of the dielectric body 10, which is the antenna body, is 10.

The impedance matching characteristics shown in FIG. 10 are those when the dielectric lens 19 is not mounted. FIG.
The impedance matching characteristic shown in 1 has a dielectric constant ε =
No. 34 when the dielectric lens 19 is mounted, FIG. 12 is when the dielectric constant ε = 30, FIG. 13 is when the dielectric constant ε = 13, and FIG. 14 is when the dielectric lens 19 having the dielectric constant ε = 5 is mounted. .

The same reference numeral 3 is used in each of FIGS.
The characteristic curve indicated by 0 is that when a signal is input from the connector 14a, and the characteristic curve indicated by reference numeral 31 is that when a signal is input from the connector 14b (see FIG. 2).

Looking at the tendency of the impedance matching characteristics from FIGS. 10 to 14, when the dielectric lens 19 having a dielectric constant ε = 5 lower than the dielectric constant ε = 10 of the dielectric body 10 of the antenna body is mounted, Frequency band 7-1
It can be seen that the reflection loss at 3 GHz is reduced and the characteristics are improved.

Next, a second embodiment will be described with reference to FIG. However, in FIG. 15, portions corresponding to the respective portions of the conventional example shown in FIGS. 18 and 19 are designated by the same reference numerals, and description thereof will be omitted.

The dielectric antenna 34 of the second embodiment shown in FIG. 15 is different from that of the conventional example shown in FIGS. 18 and 19 in that the internal space 7 of the metal housing 2 which is a waveguide is arbitrary. It is configured by filling a dielectric material 35 having a dielectric constant.

As described above, by filling the internal space 7 of the metal housing 2 with the dielectrics 35 having different permittivities, it is possible to arbitrarily shift the operating frequency with the same waveguide shape.

This is the relationship between the wavelength λ, the speed of light c, the frequency f, the propagation velocity coefficient v in the dielectric layer, and the dielectric constant ε of the dielectric, as shown in the following equation which is the same as the equation already explained in the first embodiment. Are using.

Λ = (c / f) v v = 1 / √ε For example, as shown by the frequency characteristic curve with reference numeral 37 in FIG. 16, the permittivity ε of the waveguide antenna in the operating frequency band 17 GHz is ε = If 10 dielectrics are used, λ =
From the relationship of (c / f) · v, the frequency f after using the dielectric is
From the propagation velocity coefficient v in the dielectric 35, f · v = f · 1 / √ε = 17 × 1 / √10 ≈5.4 [GHz], which is shown by a frequency characteristic curve as indicated by reference numeral 38. Become.

That is, in the second embodiment, even if the shape of the waveguide is once determined, the usable frequency can be varied, so that it can be used in a low frequency band which cannot be used with the same shape. It will be possible.

Further, also in the dielectric antenna 34 of the second embodiment as described above, it is possible to make the dielectric antenna 34 smaller than the feeding waveguide type antenna 1 of the conventional example, almost in the same manner as described in the first embodiment. it can.

Further, as shown in FIG. 17, by mounting a dielectric lens 40 that covers the exposed surface of the dielectric 35 and has a lower dielectric constant than the dielectric 35 filled in the waveguide,
The impedance matching characteristic and the antenna gain can be improved almost in the same manner as described in the embodiment.

[0049]

As described above, according to the present invention,
There is an effect that it has electrical characteristics of a feeding waveguide type antenna, and that it is possible to reduce the size and weight and simplify the manufacturing.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a perspective view showing the configuration of the dielectric antenna according to the first embodiment of the present invention.

FIG. 3 is a first diagram for explaining a manufacturing process of the antenna shown in FIG.

FIG. 4 is a second diagram for explaining the manufacturing process of the antenna shown in FIG.

FIG. 5 is a third view for explaining the manufacturing process of the antenna shown in FIG.

FIG. 6 is a fourth diagram for explaining the manufacturing process of the antenna shown in FIG.

7 is a cross-sectional view of the antenna shown in FIG. 2 taken along the line BB '.

FIG. 8 is a diagram showing a weight characteristic of a dielectric antenna with respect to a dielectric constant.

9 is a diagram showing a configuration in which a dielectric lens is attached to the antenna of the first embodiment shown in FIG.

FIG. 10 is a diagram showing impedance matching characteristics when a dielectric lens is not mounted.

FIG. 11 is a diagram showing impedance matching characteristics when a dielectric lens having a dielectric constant ε = 34 is mounted.

FIG. 12 is a diagram showing impedance matching characteristics when a dielectric lens having a dielectric constant ε = 30 is mounted.

FIG. 13 is a diagram showing impedance matching characteristics when a dielectric lens having a dielectric constant ε = 13 is mounted.

FIG. 14 is a diagram showing impedance matching characteristics when a dielectric lens having a dielectric constant ε = 5 is mounted.

FIG. 15 is a perspective view showing the structure of a dielectric antenna according to a second embodiment of the present invention.

FIG. 16 is a diagram showing frequency characteristics for explaining a frequency shift.

FIG. 17 is a diagram showing a configuration in which a dielectric lens is attached to the antenna of the second embodiment shown in FIG.

FIG. 18 is a perspective view showing a configuration of a conventional feeding waveguide type antenna.

19 is a cross-sectional view taken along the line AA ′ of the antenna shown in FIG.

FIG. 20 is a perspective view showing the configuration of another conventional feeding waveguide type antenna.

[Explanation of symbols]

 10 Dielectric 11 Metal plating film 12 Radio wave emission surface 14a Power supply connector

Claims (6)

[Claims] 1. An antenna characterized in that a metal plating film is applied to a portion other than a radio wave radiation surface of a dielectric body to which a power feeding connector is connected. 2. The antenna according to claim 1, wherein a power feeding electrode of the connector protruding on an arbitrary surface of the dielectric is bonded to the metal plating film with a conductive resin material. 3. The antenna according to claim 1, wherein the shape of the dielectric is a shape of an internal space of a feed waveguide type antenna in which a ridge is provided in the internal space. . 4. An antenna of a feeding waveguide type having an internal space and a radio wave emitting surface which is an opening of the space, wherein the internal space is filled with a dielectric. 5. A dielectric substrate having a dielectric constant lower than that of the dielectric is fixed to the radio wave radiation surface so as to cover this surface. The antenna described. 6. The antenna according to claim 1, wherein a dielectric having a dielectric constant different from that of the dielectric is used.