JPS63300608A - Antenna system - Google Patents

Abstract

PURPOSE:To attachably/detachably obtain an antenna system whose directivity fre quency characteristic is able to be decreased by assembling a cone taper and a directivity shaping concave lens to a radome incorporatedly and adopting a structure to be screwed to a circular waveguide of a horn antenna main body. CONSTITUTION:Denoting the mechanical size being a difference of path length of an aperture face B without a concave lens 3c as delta and the size of the concave lens 3c as (d), then the phase phi at the aperture ridge face B is retarded by equation I only (inverse of lambdag represents an integration mean value of a guide wavelength). In adding the concave lens 3c to the aperture, a new phase error DELTAphi (equation II) is added when a radio wave is transmitted therethrough, where lambda is a free space wavelength and epsilonv is a specific dielectric constant of the type of material of the concave lens. In mounting the concave lens 3c, the phase lag phi at the aperture ridge end face B with respect to the center is expressed as equations I+II=equation III, and the phase error is further increased with high frequencies in comparison with the equation I. The beam width is wider when the phase error is increased in the directivity of the horn antenna and the frequency characteristic value as to the directivity is decreased before the mounting in mounting the concave lens 3c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antenna device mounted on an aircraft or the like and used for transmitting and receiving radio waves.

[Prior art J Figures 12 (,) (b) and 13 are, for example, M engineering C
ROWAVE RESEARCHHC0RPORATIO
FIG. 12(b) is a sectional view showing a conventional antenna device shown in the catalog of N.
It is a cross-sectional view when cut along @ and B-B' line, (
IJ is a horn antenna consisting of a ridge 4-wave tube section, a ridge calyx wave tube, a circular waveguide conversion section, a circular 4-wave tube section, and a conical taper (FIG. 9 only), (2)/ri the horn antenna (1
) is a dielectric phase shifter loaded in the circular tube section, and (3) is a radome attached to the tip of the horn antenna (1) by adhesive. This adhesion is sufficiently strong because it is carried out to protect the inside of the horn antenna (2) from the surrounding conditions when it is mounted on an actual aircraft such as an aircraft, so as to keep the inside airtight.

Next, the operation will be explained. The radio waves transmitted from the ringed wave tube section of the horn antenna (1) follow the constant wave tube, the circular waveguide conversion section, and enter the circular 4 wave tube section, where the dielectric phase shifter loaded there. After being converted into a circularly polarized wave by the device (2), it is completely transmitted through the radome (3) and radiated into space.

If the material, thickness, and surface coating of the radome (3) are selected with emphasis on radio wave transmission characteristics, mechanical properties such as strength and corrosion resistance, and environmental resistance may not be sufficient.

In this case, the radome (3) may deteriorate and need to be replaced due to use under harsh environmental conditions such as when mounted on a Fi flight. However, since the radome (3) is integrally bonded to the horn antenna (1), replacement work is not easy.

In addition, the aperture diameters DI and D2 of the horn antenna (1) are determined not only by the radiation characteristics such as gain and directivity, but also by the requirements for aerodynamic resistance when mounted on Hungry Sakura; This tendency tends to become sharper in proportion to the frequency, and this may be a disadvantage when using a wide band.

[Problems to be Solved by the Invention] Conventional antenna devices have limited configurations as described above, so when the radome needs to be replaced due to deterioration, it is difficult to replace it, and it is not easy to replace it due to the deterioration of the radome. Problems such as the possibility of not being able to meet sexual needs were common.

This invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an antenna device in which the radome can be easily attached and detached, and the same wave number characteristic of directivity can be reduced.

[Means for solving problems]

The antenna device according to the present invention has a structure in which a conical taper part corresponding to the mouth part of a radome VC horn antenna and a concave lens for directivity shaping can be integrated and screwed into the circular waveguide part of the horn antenna body. It is.

[Effect]

With Jin's invention, the radome can be attached and detached by tightening or loosening the screw at the base, making replacement work extremely easy.Furthermore, since the effectiveness of the four lenses increases as the frequency increases, the directivity can be improved. The dependence on the number of circumferences IjL is reduced.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (3a) is a hemispherical radome outer skin made of dFRP isotropic dielectric material. (3b) is a metal lens with a conically tapered tip and a threaded base, and (3C) is a concave lens made of dielectric material such as FRB. It is fixed to the inner surface with adhesive.

In Fig. 2, (la) Vi is a horn antenna J body with screw processing and O-ring vortex processing applied to the tip, and (2) u is a dielectric phase shifter loaded inside the horn antenna main body (la). .

In Figure 3, (4) is the horn antenna body (la)
This is an airtight O-ring embedded in the O-ring groove.

The mechanism of mouth radio wave radiation, which will be explained next, is the same as that of the conventional device.
b) is fitted as shown in FIG. 3, thereby exhibiting the same function as the horn antenna (1) in the conventional device.

Since a concave lens is attached to the entrance of the antenna, this effect will be explained with reference to FIG. 4.5. FIG. 4 shows the mechanical dimensions of the path length difference at the opening when there is no concave lens, and FIG. 5 shows the mechanical dimensions ff1d of the concave lens attached to the surrounding area f'i.

In FIG. 4, the phase at the edge of the opening lags behind the center. Here, s2 is the average value of the channel wavelength of the f$ surface wave transmission portion within the horn antenna.

Next, if a concave lens is added to the aperture as shown in Figure 5, when the radio wave passes through this part, the phase error will be vcvfr Δ- 2πd 7111 = - Sue (Vπ-1)
...(2) is added. Here λ
is the free space wavelength, and g7 is the relative permittivity of the material constituting the concave lens.

Therefore, when a concave lens is attached, the phase lag at the edge of the opening with respect to the center is the sum of equations (1) and (2) == ``Shogi player''(v'lσ° - 1)
...(3) λ2 λ, and as the frequency becomes more cylindrical than in equation (1), the phase error becomes even larger. As for the directivity of a horn antenna, the beam width tends to become wider as the phase error of the entrance part becomes larger, and as a result, by installing a concave lens, the circumferential Ijt characteristic of the directivity becomes smaller than before installation. Figure 6 conceptually shows this young fruit.

Since the radome (3) is screwed into the main body of the horn antenna (1a), it can be easily attached and detached, and the electrical contact between the two is completely maintained by contacting thJB in FIG. 3. In order to completely contact blood B, a gap is created in direction A, but since an O-ring (4) is placed in this area with device A, airtightness is maintained.

In addition, in the above embodiment, the radome was explained as having a fixed conical taper shape at the base end of the elliptical surmacund part and a fixed concave lens shape, but since the directivity characteristics of the antenna are influenced by the shapes of the above two places, Figure 7 (a) (b)
) As shown in (c), by preparing several types of beams with different shapes, that is, with different directivity frequency characteristics, the following advantages arise.

Consider three types of radomes to be prepared as shown in Figures 7(a), (b), and (c).

In Figure 7 (a) (b) (C) (3b(1))
, (3b(2)), (3b(3))II'i respectively have different conical taper shapes at the tips, opening angles θ1, θ2, θ3 and opening diameters, %D2, D, ( 30(
1)), (3c(2)), and (3c(3))t/'i are concave lenses with different shapes (thickness dis '12, aa, etc.), and as in the above embodiment, all of them have a radome outer skin. It is fixed to the inner surface of (3a) with adhesive. Makunto 5 (3b(1)), (3b(匈), (3b(3))
The base of each of the radomes (3(1)), (3(2)), and (3(3)) has the same structure as the antenna body (la) used in the above example. ) can be attached and detached.

The antenna body (la) has a radome (3(1)), (3(
Figure 8(a) shows the state in which 2)) and (3(3)) are installed.
(b) Shown in (c).

FIGS. 9(a), 9(b), and 9(c) show trends in the frequency characteristics of the phase lag m (phase error) at the edge of the opening based on the center of the exit corresponding to each exit shape.

The directivity and gain of the horn antenna are determined by the rI eye aperture and the electric field distribution on the aperture surface, so Fig. 8(a)(b)
Radome (3(1)), (3
(2)), (3(3)) to a common horn antenna body (
The tendency of the frequency characteristics of the gain and beam width when installed in the optical system 1a) is K as shown in FIGS. 1θ and 11.

Therefore, depending on the purpose of use, radome (3(1)),
By replacing (3(2)) and (3(3)), it is possible to easily obtain antenna devices with different frequency characteristics.

[Effects of the Invention] As described above, according to the present invention, the radome is provided with a metal maknt portion having both a threaded structure and a conical taper structure, and is detachable from the horn antenna body, which facilitates replacement and improves the maintainability of the device. can be expected to improve. Furthermore, radome V
Since C also has a built-in chiroelectric concave lens, it has the effect of providing a wider-band antenna device with a smaller 8-helical directivity characteristic.

[Brief explanation of the drawing]

FIG. 1 (a) (b) t:tThe configuration of the antenna device according to this complete embodiment! ! 2(a) and 2(b) are cross-sectional views and front views of a horn antenna body and a dielectric phase shifter, which are components of an antenna device according to an embodiment of the present invention. , FIG. 3 is a sectional view of an antenna device according to an embodiment of the present invention, FIGS. 4, 5, and 6 are explanatory diagrams showing the effect of a concave lens. FIGS. ) ld, cross-sectional view of a radome according to another embodiment of the invention, No. 8 m (a) (b) (
c) shows the state in which the radome (3 (1) is included (3 (2)), (3 (3) is attached to the horn antenna body (la)
Fig. 9 (,) (b) (C) shows the radome (3
(1)), (3(2), and (3(3))) are attached to a common horn antenna (la). Figures 12 and 13 are cross-sectional views showing the conventional antenna device. In the figure, (la) is a characteristic diagram showing the difference in the frequency characteristics of the gain of the radome and the difference in the wave number characteristics of the beam width. Horn antenna main body, (2) is dielectric phase shifter, (3) is radome, (3a) is radome outer skin, (3b) is Makunto, (3c) is N lens, (
4) is a 0 ring. In each figure, the same reference numerals 8/fi or equivalent parts are indicated. Agent: Masu Oiwa (OkiN Tame)

Claims (1)

[Claims] In an antenna device equipped with a radome on its opening surface for the purpose of protection from surrounding conditions, the radome itself incorporates a conical taper part and a dielectric lens part, which are part of the antenna's function, and has a threaded base. An antenna device characterized in that it can be attached to and detached from an antenna body.