JPH0680971B2 - Dielectric loaded antenna with reflector - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use in, for example, transmission and reception of radio waves in the frequency band of microwaves or higher, and has a dielectric plate having a reflector with significantly improved operating gain and radioactivity. Regarding body-loaded antenna.

Prior Art FIG. 19 is a sectional view showing the configuration of a typical prior art short-circuit buckeye antenna (hereinafter, abbreviated as SBF antenna) 1. The SBF antenna 1 will be described with reference to FIG. The SBF antenna 1 includes, for example, a wave source 2 of a radio wave such as a dipole antenna and a pair of reflectors 3 made of parallel metal plates arranged on opposite sides with respect to each other.
Including 4 and. The reflector 4 has a cylindrical portion 4a having a rising height a1 (for example, 0.25λ) toward the reflector 3 side. Reflector 3,
The outer shape of 4 is, for example, a square or a circle, and the outer dimension D1 is selected to be 0.4λ with respect to the wavelength λ of the radio wave used, and the outer dimension d1 is 2.0λ when the outer shape is a circle. The distance h1 between the reflectors 3 and 4 is set to λ / 2 with respect to the wavelength λ used. The SBF antenna 1 realizes radiation by utilizing the reflection of the radio wave between the reflectors 3 and 4 and the diffraction of the radio wave at each end of the reflectors 3 and 4.

With such an SBF antenna 1, the aperture efficiency is at most about 100%.
It is known that a gain of about 15 dB can be obtained in the above, but it is well known that it is difficult to achieve a higher aperture efficiency and operating gain with the SBF antenna 1 having such a configuration.

FIG. 20 is a perspective view showing the configuration of a second conventional dielectric rod antenna (hereinafter referred to as a rod antenna) 5. The rod antenna 5 will be described with reference to FIG. The rod antenna 5 excites the dielectric rod 7 fixed to one end of the waveguide 6 along the longitudinal direction by the waveguide 6, and realizes radiation by using the generated surface wave. In such a rod antenna 5, the diameter D2 of the dielectric rod 7
Is not more than the used wavelength λ, and the rod length D3 needs to be 5λ to 10 number × λ. Therefore, it is known that such a rod antenna is inevitably difficult to miniaturize in terms of configuration, and the operating gain is only about 16 to 17 dB.

FIG. 21 is a plan view showing the basic configuration of the Yagi antenna 8 of the third conventional art. The Yagi antenna 8 will be described with reference to FIG. The Yagi antenna 8 includes a feeding element 8a, a director 8b, and a reflector 8c. Since the Yagi antenna 8 uses a resonant element made of a conductor rod, there is a problem that the frequency band used is narrow.

SUMMARY OF THE INVENTION In view of the problems to be solved by the invention, in particular, an antenna that transmits and receives radio waves in the frequency band of microwaves and millimeter waves or higher can be downsized, and an antenna that can significantly improve operating gain and radiation efficiency is desired. It had been.

An object of the present invention is to solve the above problems and to provide a dielectric loaded antenna having a reflector which can significantly reduce the configuration and can significantly improve the operating gain and the radiation efficiency.

Means for Solving the Problems The present invention is directed to a waveguide (12) and an end portion of the waveguide (12) fixed by expanding outwardly in a direction perpendicular to the axis of the waveguide (12). And a metal flat plate-like reflector (13) having an opening (13a) communicating with the waveguide (12) and a certain distance in front of the reflector (13),
A dielectric loaded antenna having a reflector, characterized in that a surface (14s) facing the reflector (13) includes the reflector (13) and a dielectric (14) parallel to the reflector (13).

A preferred embodiment of the present invention is configured such that the surface (13s) of the reflector (13) facing the dielectric (14) is a substantially conical surface, and faces the reflector (13) of the dielectric (14). The surface (14s) and the surface (14r) opposite to the surface (14s) are connected to the reflection plate (13).
Is formed in a shape corresponding to the surface (13s).

In a preferred embodiment of the present invention, the reflector (13) is formed in a shape in which a pair of flat metal plates form an angle θ2 with each other, and the dielectric (14) corresponds to the reflector (13). It is characterized in that the cross section perpendicular to the axis is formed in a substantially V shape.

A preferred embodiment of the present invention is characterized in that a plurality of combinations of the waveguide (12), the reflector (13) and the dielectric (14) are arranged and used as an array antenna.

Further, the present invention provides a reflector (13) and a dielectric body (a surface facing the reflector (13) which is arranged in front of the reflector (13) with a certain distance therebetween and is parallel to the reflector (13). A dielectric loaded antenna having a reflector, characterized in that it includes a reflector (13) and an antenna interposed between the reflector (13) and the dielectric (14).

A preferred embodiment of the present invention is characterized in that the antenna is a dipole antenna.

A preferred embodiment of the present invention is characterized in that the antenna is a patch antenna.

A preferred embodiment of the present invention is characterized in that the antenna is a stripline antenna.

Further, a preferred embodiment of the present invention is characterized in that a plurality of combinations of the reflector (13), the dielectric (14) and the antenna are arranged and used as an array antenna.

Operation According to the present invention, the opening 13a of the reflector 13 and the antenna 17,
A wave source having an arbitrary polarization mode such as 18, 19 and a reflector disposed in the vicinity of the wave source, the surface facing the wave source having a finite area, and the surface opposite to the reflector with respect to the wave source, at least the surface facing the reflector. Includes a reflector and a dielectric formed in parallel to form a dielectric loaded antenna. In such a dielectric loaded antenna, the radio wave from the wave source is multiply reflected between the reflector and the dielectric, or inside the dielectric.

According to the present invention, by appropriately selecting the mutual distance between the dielectric, the wave source, and the reflector, and the dimensions and permittivity of the dielectric,
The electromagnetic field distribution (particularly the phase) near the dielectric due to the superposition of the vibration component in the traveling direction of the radio wave in the dielectric body, the vibration component in the direction perpendicular to the traveling direction, and the vibration component between the reflector and the dielectric body. Uniformize. To explain this in more detail,
Considering the case where a relatively wide plate dielectric 14 is loaded on a point wave source as shown in FIG. 22, a part of the radio wave radiated from the wave source 31 is between the dielectric 14 and the reflector 13 which is a ground plate. While propagating to the break of the dielectric 14 while repeating reflection,
Meanwhile, a leaky wave is generated little by little through the dielectric substance 14, and its phase plane is aligned in a certain direction like a wavy line and exhibits a sharp directivity in a direction perpendicular to the equiphase surface. This is as if it were the radiated wave from the image source train, as shown in FIG. Distance h between dielectric 14 and reflector (ground plate) 13
Is an integral multiple of 1/2 wavelength, and the thickness t of the dielectric 14 is 1/4 dielectric 14
When the inner wavelength is an odd multiple, the directivity is in the front direction, and if the dielectric 14 and the reflector 13 are infinitely wide, the gain of the wave source is double the relative permittivity. Therefore, if the dielectric constant of the dielectric material 14 is high, the reflection coefficient is high, the vibration is less likely to be attenuated, the vibration is widely spread in the lateral direction, and the effective area is increased, so that a high gain is obtained. This is the theory of the invention.

The relative permittivity of this dielectric 14 is small.
Most of the energy is radiated forward in the area where the diameter of 4 is 2.5 wavelengths. If the width of the dielectric 14 is actually finite and the diameter is, for example, about 3 wavelengths or less, the dielectric 14 in the thickness direction,
Alternatively, the wave propagating in the lateral direction is repeatedly reflected between the reflector 13 and the dielectric 14, and the wave propagating in the lateral direction is reflected on the side wall of the dielectric 14, that is, the discontinuous surface and propagates in the opposite direction, and on the opposite discontinuous surface. Reflect again. In this way, a lateral vibration component is generated.

Next, as shown in FIG. 23, considering a case where a rod-shaped dielectric 14 having a low dielectric constant and a diameter of about 0.5 wavelength is loaded in front of the wave source 31,
The radio wave entering the dielectric 14 is repeatedly reflected on the side surface of the dielectric 14 and propagates forward. As shown in FIG. 23, the incident path and the reflected path appear to be disjointed, but these propagate in the HE _{11 state} (surface wave) while forming an equiphase surface in the cross section of the dielectric 14. Originally, surface waves do not radiate radio waves, but since the dielectric 14 has a finite length, the dielectric 14 as a whole radiates radio waves, and when the Hansen-Woodyard condition is satisfied, a high gain is obtained.

FIG. 24 shows a dielectric on the wave source on the reflection plate (ground plate) 13.
14 is a loaded figure, which shows that the dielectric has a lens-like effect on the radiated wave. That is, a path that is obliquely incident on the path near the center of the dielectric is refracted into a prism shape at the corner of the dielectric. The distance that this path reaches near the upper end surface is longer than the path that passes near the center, but since the distance that radio waves pass through the dielectric is short, the difference in the arrival time is reduced depending on the dimensional conditions of each part. be able to. In other words, since the phase difference can be reduced, a wave close to a plane wave can be obtained. In the present invention, in order to confirm the effective area of the dielectric 14 when the gain becomes high in the front direction, the thickness of the dielectric is λg / 4 (λg is the wavelength in the dielectric), the dielectric 14 and the reflector 13 When a (the lambda ₀ and space wavelength) λ _0/2 intervals Yuku and size of the dielectric 14 was gradually reduced as originally have breadth of possible gain permittivity fold increases more than that, There is some thickness, and the distance between the dielectric 14 and the ground plate 13 is λ.
_It does not have to be 0/2, and the size of this interval improves the compatibility with the wave source. In this case, a high gain antenna can be realized with a dielectric length much shorter than that of the dielectric rod antenna. For example, when the cross section of a prismatic dielectric is 2.5λ _0, a gain of about 18 dBi can be obtained. This does not apply to the theory of dielectric covered antennas or the theory of dielectric rod antennas. However, to be able to apply the theory of the rod antenna diameter is about 1 [lambda ₀ or less, the 4~5λ diameter _0, the dielectric 14 and the distance of the ground plate 13 is lambda _0/2 of the dielectric covered antenna theory Will be able to adapt.

In the dielectric loaded antenna of the present invention, the diameter of the dielectric 14 is the element of the dielectric covered antenna, that is, the leaky wave, and the element of the dielectric rod antenna, that is, the surface wave (HE).
It is thought that it is a combination of radiation waves that can obtain the lens effect. Therefore, the term "superimposition" means that these waves are combined, and the combination conditions of the relative permittivity of the dielectric 14, the diameter D, the thickness t, and the distance h from the reflection plate (ground plate) 13 are combined. Since the phase distribution of the electromagnetic field on the front surface of the dielectric is broadened and made uniform (in-phase), a high gain can be obtained.

Since the interval h can adjust the matching with the wave source, radio waves can be efficiently emitted. The efficiency of the antenna depends on what percentage of the power input to the antenna is radiated, and in this case, if dielectric loss is small, it is only a matter of matching. As a result, high operating gain and high efficiency of the antenna are realized, and therefore, the configuration can be remarkably downsized as compared with the conventional antenna of the same efficiency or the same operating gain.

Embodiment 1 FIG. 1 is a perspective view showing a basic structure of a dielectric loaded antenna (hereinafter, simply referred to as an antenna) 11 according to an embodiment of the present invention, and FIG. 2 is a plan view of the antenna 11. The antenna 11 of this embodiment will be described with reference to FIGS. 1 and 2. The antenna 11 of the present embodiment includes a waveguide 12 whose cross section perpendicular to the axis is, for example, a rectangular shape. One end in the longitudinal direction extends outward perpendicularly to the axis of the waveguide 12 and is made of a metal material. The rectangular flat plate-shaped reflection plate 13 is fixed. An opening 13a communicating with the waveguide 12 is formed in the reflection plate 13.
Forward from the reflector 13 (right side in FIG. 1, upper side in FIG. 2)
Then, a rectangular parallelepiped dielectric 14 is arranged at a distance h from the reflection plate 13. The dielectric 14 is made of, for example, Teflon resin, polyethylene resin or polypropylene resin.

The reflector 13 has, for example, a rectangular outline and side lengths D1 and D.
Having 2. The dielectric 14 has a thickness t along the axial direction of the waveguide 12, a longitudinal length D3 along two directions orthogonal to the axial direction of the waveguide 12, and a lateral length D4. The surface 14S of the dielectric 14 which faces the reflection plate 13 is, as is clear from FIG.
It is parallel to the reflector 13.

As to the antenna having the waveguide 12 as the wave source and the reflector 13 as described above, by disposing the dielectric 14 as described above, the electromagnetic wave generated from the opening 13a is indicated by an arrow A1 in FIG. As shown, the light is reflected between the reflector 13 and the dielectric 14 along both directions along the axial direction of the waveguide 12. Dielectric
Within 14, multiple reflection is carried out in the directions along arrow A1 direction and mutually orthogonal directions (shown by arrows A2 and A3 in FIG. 1) constituting a plane orthogonal to the arrow A1 direction. By this, the reflector
Between 13 and the dielectric 14 and inside the dielectric 14, the arrow A1
Surface waves and diffracted waves are excited in the ~ A3 direction to generate standing waves.

Further, as described above, the electromagnetic wave is reflected along the arrow A1 direction between the reflecting plate 13 and the dielectric body 14, and with respect to such an electromagnetic wave, each end portion 15 of the reflecting plate 13 and the dielectric body 14 is reflected. , 1
Diffraction at 6 increases the operating gain. That is, the electromagnetic field distribution (particularly the phase) near the dielectric 14 can be made uniform. The homogenization referred to here means the electromagnetic wave reflected or diffracted by the end portions 15 and 16, the dielectric 14 and the reflection plate 13.
It means the effect of superimposing the electromagnetic waves multiply reflected between and. Further, the area of the reflection plate 13 is finite, and therefore, by repeating reflection or diffraction at the end portions 15 and 16, a state occurs in which the phases of radiated electromagnetic waves are aligned. This improves the operating gain.

FIG. 3 is a graph showing the characteristics of the antenna 11 described above.
The horizontal axis is the numerical value obtained by normalizing the thickness t with the wavelength λ ₀ used,
The vertical axis is the operating gain. The dielectric 14 of the present embodiment, for example, in Atsute dielectric constant = 2.0 with Teflon, choosing the spacing h = λ _0/2. This example will be described below. Fig. 3 Line l1
Shows the characteristics in the case of D1 = D2 = D3 = D4 = 1.5λ ₀ (1) in FIG. 1, and the line 12 shows the characteristics in the case of D1 = D2 = D3 = D4 = 2.0λ ₀ (2) The characteristic is shown, and the line 13 shows the characteristic in the case of D1 = D2 = D3 = D4 = 4.0λ ₀ (3).

Hereinafter, the characteristics of the antenna 11 will be described with reference to FIG. As is clear from FIG. 3, in the case of the above formula 1, the operating gain becomes maximum at t / λ ₀ ≈1.5 (4), and in the case of the formula 2, t / λ ₀ ≈2. It is understood that the operation gain is also maximized in (5). In the case of the third formula, the operating gain oscillates as shown in FIG. 3, and in the range of t / λ ₀ > 0.5 (6), the maximum values of the vibrations are almost equal, which is the dielectric
It is understood that 14 approximates the phenomenon when it is sufficiently (or infinitely) wide.

That is, in the antenna 11 having the configuration shown in FIGS. 1 and 2, when the areas of the surfaces 13s and 14s of the reflection plate 13 and the dielectric 14 which face each other are about 16λ ₀ ² or more, the above-mentioned end portion 15 is formed. It is understood that the effects due to reflection and diffraction at 16 and 16 disappear. It is also shown that the operating gain of the antenna 11 is improved as the side lengths D1 to D4 of the reflector 13 and the dielectric 14 are changed from 4λ ₀ to 1.5λ ₀ . The present inventor has confirmed that such a tendency is the same even when the distance h between the reflection plate 13 and the dielectric 14 is changed.

FIG. 4 is a graph showing the experimental results regarding the operating gain and the aperture efficiency with respect to the used frequency f [GHz] of the antenna 11 of the present invention. The "x" mark in FIG. 4 indicates the aperture efficiency, and the "." Mark indicates the operating gain. The dielectric in this embodiment, the third is in the same manner as in the description with reference to FIG an Atsute dielectric constant = 2.0, for example Teflon, are chosen interval h = λ _0/8. Present inventors, when the interval h is lambda _0/8, it was confirmed that such operating gain and aperture efficiency as described below is most preferable value. This experimental result shows that, in the antenna 11 having the structure shown in FIG. 1, when the side lengths D1, D2, D3, D4 are collectively referred to by the reference symbol D, D / λ ₀ = 1.5 (7) t / λ ₀ = 1.874 (8) h / λ ₀ = 1/8 (9) At this time, as is clear from FIG. 4, the frequency bandwidth BW is BW / f ₀ > 0.3 ... (10), and the efficiency is 100 within the range of the frequency bandwidth BW.
%, And the maximum efficiency of 225% was obtained.

FIG. 5 is a graph showing the relationship between frequency and voltage standing wave (VSWR). The experimental data shown in FIG. 5 was performed under the conditions of the above formulas 7 to 9. Waveguide 12 here
The voltage standing wave ratio (VSWR) of TE ₁₀ mode is “・” in Fig. 5.
Indicated by. VSWR <1.5 (11) is obtained within the frequency band shown in FIG.

6 and 6A show the E-plane (electric field plane) and the H-plane of the electromagnetic wave at the working frequency f ₀ under the conditions of the above-mentioned formulas 7 to 9.
It is a graph which shows the radiation characteristic of each surface (magnetic field surface).
It was confirmed that the antenna 11 of this example has the radiation characteristic shown in FIG.

The inventor of the present invention conducted an experiment comparing the function of the antenna 11 of the present invention with a typical electromagnetic horn antenna of the related art. The principle configurations of the electromagnetic horn antenna 23 and the antenna 11 used at this time are shown in FIGS. 6B and 6C. The electromagnetic horn antenna 23 is configured by coaxially connecting a rectangular truncated pyramid-shaped electromagnetic horn 25 to a tip end portion of a waveguide 24. An example of dimensions of each part of the electromagnetic horn antenna 23 and the antenna 11 and changes in operating gain will be described below. The outside dimension of the opening is A = 50.7m with reference to the symbols in Figures 6B and 6C.
m, B = 66.7 mm, D = 38.1 mm, so the aperture area is 2824.0 mm ^{2 for} the electromagnetic horn antenna 23, and antenna 1
At 1, it is 1452.3 mm ² . And for the depth dimension, L =
It was designed with 119.5 mm ² and H = 50.7 mm. Each gain (dB) of such electromagnetic horn antenna 23 and antenna 11
Were 13.2 dB and 14.5 dB at the operating frequency of 8 GHz, respectively.

As described above, the antenna 11 of the present invention has an opening area that is about half that of the electromagnetic horn antenna 23 and a depth that is about the same.
The size can be reduced to 0.43 times, while the gain in the used frequency band can be improved in the range of 1.3 dB. As a result, an antenna having the same capability as the electromagnetic horn antenna 23
It was confirmed that 11 was significantly miniaturized.

Although the present embodiment has been described with reference to the aperture antenna as shown in FIG. 1, the wave source includes the dipole antenna 17 shown in FIG. 7, the patch antenna 18 shown in FIG. 8 and the strip antenna shown in FIG. The planer antenna 19 can also be easily implemented. Further, the present invention is not limited to the above wave sources, and can be implemented for any wave source including a slit antenna.

The dielectric loaded antenna using the dipole antenna 17, patch antenna 18 and stripline antenna 19 shown in FIGS. 7 to 9 as a wave source has an interposition between the reflector 13 and the dielectric 14 such as foamed styrene resin. The member 30 is arranged as a spacer. Regarding such an interposition member 30, a space between the wave source and the dielectric 14 is formed hollow. The structure using the intervening member 30 is similarly realized for the antenna 11 of FIGS. 1 and 2.

In the above-described embodiment, the reflection plate 13 is described as a rectangular plate shape and the dielectric 14 is described as a rectangular parallelepiped.
Each figure seen from the longitudinal direction of 12 (see Figure 10 and Figure 11)
It may be of rectangular or square type, as shown in
It may also be a circular type. The polarization mode of the electromagnetic wave generated from the wave source may be any of linear polarization, circular polarization, and elliptical polarization, and the shape of the dielectric 14 is a polygonal plate or a polygonal rod, a circular plate or a circular rod, or the like. Either can be implemented.

As still another embodiment of the present invention, the waveguide 12 and the waveguide 12
A metal plate-shaped reflector 13 having an opening 13a that is fixed to the end of the waveguide 12 and extends outwardly perpendicularly to the axis of the waveguide 12 and communicates with the waveguide 12, and is fixed forward from the reflector 13. A combination of a dielectric 14 having a surface 14s facing the reflection plate 13 and spaced apart from the reflection plate 13 in parallel, or a reflection plate 13;
The reflector 13 is placed in front of the reflector 13 with a certain distance.
A dielectric 14 whose surface facing the reflector 13 is parallel to the reflector 13;
A combination of an antenna interposed between 13 and the dielectric 14 may be used as a base element, and a plurality of these may be arranged to be used as an array antenna. The 12th example
Shown in Figure and Figure 13. FIG. 12 shows an arrangement of wave sources 20 and a pitch L.
It is arranged in a direction matrix. FIG. 13 shows a configuration in which the wave sources 20 are arranged in a zigzag pattern at a mutual distance L. With such a configuration as well, the effect described in the above embodiment can be realized, and an antenna having higher efficiency and higher operating gain can be configured.

Surfaces of the reflector 13 and the dielectric 14 of the present invention that face each other
In general, 13s and 14s are not limited to flat surfaces, and may be a curved surface of a quadratic or higher degree or a continuous structure of minute flat surfaces. That is, the reflection plate 13 and the dielectric material 14 referred to in the present invention are "parallel" when the surfaces 13s, 14s facing each other of the two are divided into a small area for each corresponding portion, each corresponding portion is The surfaces 13s and 14s are not limited to being flat as a whole and parallel to each other as long as they are parallel to each other.

FIG. 14 is an exploded perspective view showing the structure of an antenna 11a according to still another embodiment of the present invention. The antenna 11a of the present invention is similar to the above-described embodiment, and corresponding parts are designated by the same reference numerals. What should be noted in the present embodiment is that, for example, the reflecting plate 13 connected to the waveguide 12 as an example of the wave source is configured such that the surface 13s facing the dielectric 14 is a substantially conical surface. , And the surface 14s of the dielectric 14 facing the reflection plate 13,
The surface 14s of the dielectric 14 and the surface 14r on the opposite side are formed in a shape corresponding to the surface 13s of the reflection plate 13.

Here, the substantially conical surface formed by the surfaces 13s, 14s, 14r is
The apex angle θ1 when cut at a virtual plane including the axis is the
It may be chosen to be an obtuse triangle as shown in FIG. With such a configuration, it is possible to achieve the same effects as the effects described in the above-described embodiment.

FIG. 15 is an exploded perspective view showing the structure of an antenna 11b according to still another embodiment of the present invention, and FIG. 16 is a front view of a reflector 13 of the antenna 11b. The antenna 11b will be described with reference to FIGS. 15 and 16. The antenna 11b is similar to each of the above-described embodiments, and corresponding parts are designated by the same reference numerals. The remarkable point of the present invention is that the waveguide 12 as a wave source is used.
The reflecting plate 13 connected to is formed in a shape in which a pair of flat metal plates form an angle θ2 with each other. This angle θ2 may be selected such that θ2> 90 degrees (12). That is, the dielectric 14 is formed so that its cross-section perpendicular to the axis is substantially V-shaped. The opening 13a of the reflector 13 has a length L1 along the longitudinal direction of the joint 13b of the reflector 13.
And the length L2 in the direction orthogonal to this is formed so that L1 <L2 (13). Even with such an antenna 11b, the same effects as the effects described in the above-described embodiment can be realized.

FIG. 17 is an exploded perspective view showing the structure of an antenna 11c according to still another embodiment of the present invention. This embodiment is basically similar to the antenna 11b described with reference to FIG. 15 and FIG. 16, and instead of the waveguide 12 as the wave source, the patch array antenna 22 of the joint 13b of the reflector 13 is used. That is, they are arranged in parallel on both sides. With such a configuration, it is possible to obtain the same effect as that of the above-described embodiment.

FIG. 18 shows an antenna 11d according to still another embodiment of the present invention.
FIG. This embodiment is also basically similar to the antenna 11b described above, and its feature is that the patch array antennas 22 are arranged in a single row on the joint portion 13b of the reflection plate 13 along the longitudinal direction thereof. With such a configuration, the same effects as the effects described in the above-described embodiment can be obtained.

In the antenna 11a described with reference to the fourteenth expression, the reflector 13 and the dielectric 14 are formed to have a substantially conical surface, but the shape is not limited to such a conical surface and may be a polygonal pyramid surface. You may form.

FIG. 18A is a graph showing the operating gain and aperture efficiency of a dielectric loaded antenna according to still another embodiment of the present invention described later. The dielectric loaded antenna of the present embodiment is similar to the configuration shown in the first drawing, and is characterized in that the dielectric constant of the dielectric 14 provided facing the reflection plate 13 is selected to be, for example, about 8.6. With such a structure, the characteristics shown in FIG. 18A can be obtained. The line l5 in FIG. 18A shows the operating gain of the antenna 11e, and the line l6 shows the aperture efficiency thereof, which is 160% at maximum in the above configuration example. Line l7
In the structure of this embodiment with reference to FIG.
The operating gain is shown without.

FIG. 18B is a perspective view showing a dielectric loaded antenna 11e according to still another embodiment of the present invention. This embodiment is similar to each of the above-described embodiments, especially the embodiment of FIG. 8, and corresponding parts are designated by the same reference numerals. The point of interest in this embodiment is that
That is, the dielectric 14 arranged on the patch antenna 18 formed on the reflector 13 is selected to have a dielectric constant of, for example, about 8.6. With this configuration,
It is possible to obtain operating characteristics as shown in FIG. 18C. 18th C
In the figure, the line l8 shows the operating gain of the dielectric loaded antenna 11e, and the line l9 shows the dielectric 1 in the configuration of FIG. 18B.
It shows the operating gain when 4 is not loaded.

As shown in FIGS. 18A to 18C, by selecting the dielectric constant of the dielectric 14 to be a relatively large value, the frequency bandwidth described in the above embodiment becomes relatively narrow, but it is small. Can improve the operating gain. This is because the resonance phenomenon of the dielectric 14 becomes significant as the dielectric constant of the dielectric 14 increases.

FIG. 18D is a graph showing relative radiated power when the resonance frequency fε of the dielectric 14 is selected to have different values with respect to the resonance frequency fp of the patch antenna 18 in the configuration of FIG. 18B. The line l10 in FIG. 18D shows the change in relative radiant power when the dielectric 14 is not loaded in the configuration of FIG. 18B, and the line l11 shows the change in relative radiant power when the dielectric in FIG. 18B is loaded. Show.

As shown in FIG. 18D, the patch antenna 18 and the dielectric 1
By choosing each resonance frequency fp, fε of 4 to a different value,
It is understood that the frequency bandwidth has been expanded. As a result, even when the dielectric 14 having a relatively high dielectric constant is selected,
The configuration of the antenna 11 can be miniaturized by the increase of the operation gain described above, and the decrease of the frequency bandwidth can be compensated by shifting the resonance frequencies fp and fε.

Further, when the array antenna is configured using the dielectric loaded antenna in each of the embodiments described with reference to FIGS. 18A to 18D, the characteristics of the individual dielectric loaded antennas are such that the aperture efficiency is 100% at most. It does not have to have a very high operating gain, to the extent.

The effect of the present invention will be further described. Even if there is an inefficient antenna or VSWR is 2, even if this is improved to 1, that is, even if 100% input power is radiated, the gain improvement is at most about 0.5 dB, and even if a dielectric is directly attached It can improve to 1.5th place (depending on the case). Therefore, even if VSWR is further improved by the interval h and becomes 1, the gain improvement is 0.2 dB. It is difficult to draw the gain graph though it depends on the scale width.
This is shown as in Equation 11 and FIG. In the graph of Fig. 5, the minimum VSWR is about 1.05 and the bandwidth below 1.2 is about 600MH.
Since it is z, it has been shown to be perfectly efficient in general use. The worry of dielectric loss is not a problem if Teflon, polystyrene, or polypropylene with low loss is used.

The peaks and troughs in the graph of FIG. 5 can be shifted to arbitrary frequencies depending on the thickness of the dielectric.

Next, a comparison is made between the case where the dielectric is arranged and the case where it is not arranged. Regarding this, the plot of the point where the thickness of the dielectric is 0, that is, the unloaded point is missing in FIG. The embodiment in the configuration row of the figure is shown as the frequency characteristic of gain as shown in FIG. 18A. This is indicated by l5 when the dielectric is placed and l7 when not placed.
Therefore, the radiation efficiency is compared with the aperture efficiency of l6. From this, it can be seen that the gain and efficiency are improved for each frequency.

As described above, according to the present invention, the dielectric loaded antenna is configured by including the wave source, the reflector and the dielectric, and selecting the outer dimensions of the reflector and the dielectric appropriately. In such a dielectric loaded antenna, the radio wave from the wave source is between the reflector and the dielectric,
Or multiple reflection occurs inside the dielectric. Therefore, by superposing the vibration component in the traveling direction of the radio wave in the dielectric body, the vibration component in the direction perpendicular to the traveling direction, and the vibration component between the reflector and the dielectric body, the electromagnetic field near the dielectric body is superposed. The distribution (especially the phase) is made uniform. As a result, high gain and high efficiency of the antenna are realized, and therefore, the configuration can be remarkably downsized as compared with the antenna of the same efficiency or the same gain of the prior art.

[Brief description of drawings]

FIG. 1 is a perspective view showing a basic structure of an antenna 11 according to an embodiment of the present invention, FIG. 2 is a plan view of the antenna 11, and FIG. 3 is a function t / λ ₀ of the thickness of a dielectric 14 in the antenna 11. 4 is a graph showing the gain characteristic with the parameter as a parameter, FIG. 4 is a graph showing the gain and aperture efficiency with respect to the used frequency f, FIG. 5 is a graph showing the voltage standing wave (VSWR) with respect to the used frequency f, FIG. 6 and FIG. 6A is a graph showing the directional characteristics of the antenna 11, FIG. 6B is a perspective view of an electromagnetic horn antenna 23 of a comparative example, FIG. 6C is a perspective view showing the basic configuration of the antenna 11, and FIG. 7 is a dipole antenna 17. FIG. 8 is a perspective view of a dielectric antenna according to another embodiment of the present invention using a wave source as a wave source, FIG. 8 is a perspective view of a dielectric antenna according to another embodiment of the present invention using a patch antenna 18 as a wave source, and FIG. Another embodiment of the present invention using the planer antenna 19 as a wave source Front view of the dielectric antenna, FIGS. 10 and 11 are front views showing the reflector 13 or the dielectric 14 in the embodiment of the present invention, FIGS. 12 and 13 are other embodiments of the present invention. Array antenna 21,21a
FIG. 14 is an exploded perspective view of an antenna 11a according to yet another embodiment of the present invention, FIG. 15 is an exploded perspective view of an antenna 11b according to yet another embodiment of the present invention, and FIG. 16 is an antenna. 1
1b is a front view of the reflector 13; FIG. 17 is an exploded perspective view of an antenna 11c according to still another embodiment of the present invention; and FIG. 18 is an antenna 11d.
FIG. 18A is a graph showing the characteristics of the dielectric loaded antenna of still another embodiment of the present invention, and FIG. 18B is the antenna 1
1e is a perspective view, FIG. 18C is a graph showing the characteristics of the antenna 11e, FIG. 18D is a graph showing the operation of this embodiment, and FIG. 19 is the first prior art short-circuit backup antenna (SBF) antenna 1. A sectional view, FIG. 20 is a perspective view showing a rod antenna 5 of a second conventional technique, FIG. 21 is a plan view showing a Yagi antenna 8 of a third conventional technique, and FIG. 22 is a dielectric 14 of the present invention. For explaining the principle of an antenna having
FIG. 1 is a diagram for explaining the principle of another embodiment of the present invention,
FIG. 24 is a diagram for explaining the radiation wave of the present invention. 11 …… Dielectric loaded antenna, 12 …… Waveguide, 13 …… Reflector, 14 …… Dielectric, 15,16 …… End, 17 …… Dipole antenna, 18 …… Patch antenna, 19 …… Stroke Lip line antenna, 20 ... Wave source, 21 ... Array antenna, 22
...... Patch array antenna

Claims (9)

[Claims] 1. A waveguide (12) fixed to the end of the waveguide (12) by expanding outwardly perpendicular to the axis of the waveguide (12). ) A metal plate-shaped reflector (13) having an opening (13a) communicating with the reflector (13a), and a certain distance in front of the reflector (13),
A dielectric loaded antenna having a reflector, characterized in that a surface (14s) facing the reflector (13) includes a dielectric (14) parallel to the reflector (13). 2. A surface (13s) of the reflecting plate (13) facing the dielectric (14) is formed into a substantially conical surface, and a surface (14s) of the dielectric (14) facing the reflecting plate (13). ) And the surface (14r) opposite to the surface (14s), the reflector (13)
The dielectric loaded antenna having a reflector according to claim 1, wherein the antenna is formed in a shape corresponding to the surface (13s) of the. 3. The reflector (13) is formed in such a shape that a pair of flat metal plates form an angle θ2 with each other, and the dielectric (14) has a cross section perpendicular to the axis corresponding to the reflector (13). The dielectric loaded antenna having a reflector according to claim 1, wherein the antenna is formed to have a substantially V shape. 4. A waveguide (12), a reflector (13) and a dielectric (1).
4. A dielectric loaded antenna having a reflector according to claim 1, wherein a plurality of combinations of 4) and 4 are arranged and used as an array antenna. 5. A reflector (13), and a dielectric (a surface of which is disposed in front of the reflector (13) with a certain distance therebetween, and whose surface facing the reflector (13) is parallel to the reflector (13). 14) and a dielectric loaded antenna having a reflector, characterized by including an antenna interposed between the reflector (13) and the dielectric (14). 6. A dielectric loaded antenna having a reflector according to claim 5, wherein the antenna is a dipole antenna. 7. A dielectric loaded antenna having a reflector according to claim 5, wherein said antenna is a patch antenna. 8. A dielectric loaded antenna having a reflector according to claim 5, wherein said antenna is a stripline antenna. 9. The reflector according to claim 5, wherein a plurality of combinations of the reflector (13), the dielectric (14) and the antenna are arranged and used as an array antenna. Loaded with a dielectric.