JPS60191502A - Directivity rotation radome antenna - Google Patents

Abstract

PURPOSE:To accommodate a large-sized high gain antenna into a radome of a prescribed size by providing the nearest point or cross point of plural turning shafts of the antenna to a front space to an antenna reflecting face. CONSTITUTION:A turning shaft ZZ' for azimuth angle and a turning shaft XX' for elevating angle are crossed at a point O. Then the turning shaft XX' of the azimuth angle is penetrated through a space in front of an antenna reflecting plane R where the main radiation is performed. Further, the antenna is so formed that the center point N of the maximum outer diameter QQ' of an antenna structure approaches the center O of the antenna rotation. As a result, the diameter of the antenna reflection plane R accommodated in the radome D is increased. Thus, the large-sized high gain antenna is accommodated in the radome of a prescribed size.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention is a radiator that can control the pointing direction by a plurality of rotation axes, and has a radome in the vertical direction. It's about Dome Antetsu.

Mobile satellite P communications service or mobile broadcasting satellite reception servicef/Af
In such cases, an earth station antenna installed on a moving object such as a ship, an aircraft, or an 8-vehicle responds to the movement of the moving object back and forth or to the left or right, or deflects the VC force I, changing its main radiation direction to fl.
i! It must be equipped with the ability to rotate the main radiation direction so that it always faces the satellite correctly.Such directivity 19) It is usually best to protect the main radiation direction from the satellite. Yes, special VC maritime VC for satellite communication
In order to protect against the harsh external environment of a ship, such as waves, wind pressure, rain, snow, and ice, the antenna and communication equipment are protected by a radome made of hard ribs. Here, in a moving body, it is desirable that the shape of such a hard radome is as small as possible in terms of installation. On the other hand, it is known that the larger the shape of the antenna, the better the communication performance. However, no single antenna with directional rotation has been proposed to address these mutually contradictory demands.

1F/l, 1. −+ μslt M, ζ2, y,
= −2, / : j 41J:l+−诹−1;'II
This shows an example of the structure of a ditropic radome antenna, in which a parabolic antenna 1 equipped with a radiator P2 and a reflector i4R is rotated inside a radome D by a rotating machine 47&E. Further, the transmitting/receiving amplifier A connected to the antenna is configured to rotate together with the parabolic antenna 1. In order to simplify the explanation, the rotation mechanism of the antenna 1 is shown in this example for a case in which rotation is performed on two axes of the azimuth angle AZ and the elevation angle EL. Electrical drive information for two-axis rotation is well known as it can be obtained separately, and is not directly related to the present invention, so a description thereof will be omitted.

Now, in the A2 rotation, the support frame C fixed to the rotary table B rotates around the direction 11IllllZZ'. Also, the elevation angle EL
, the rotation is made to rotate around the XX' axis perpendicular to Zz'.

FIG. 1 shows a state in which the antenna 1 is directed toward the zenith. Note that the antennas in the figures from FIG. 2 to FIG. 6 also show the same directional state as in FIG. 1.

, and the same symbols as in FIG. 1 in these figures indicate the same names.

In FIG. 1, the EL rotation axis XX' passes through the space behind the antenna reflecting surface R, and the radius of rotation of the antenna is determined by the lengths of OP and OQ or OQ' with respect to the midpoint O. MLQ and Q' are both ends of the diameter of the reflecting surface R of the antenna as shown. In this way, in the conventional radome antenna made at $71, the outer diameter of the antenna reflection surface QQ'
is much smaller than the inner diameter of the radome D, making it a small antenna. In other words, given the size of the antenna, the size of the radome that covers the antenna needs to be considerably larger than the size of the antenna reflecting surface.

Figure 2 shows the use of four helical antenna elements that can easily generate circularly polarized waves instead of a parabolic antenna.
+P2+Py+P4 are arranged symmetrically to each other on a reflection plate R', which is a diagram of a conventional structure example different from FIG. 1; This rotating directional radome antenna is also the same as in Figure 1.
Since the L rotation axis XX' is located in the space behind the reflector R', the rotation radius of the antenna is determined by the length of OQ or OQ'. In other words, since the antenna can rotate within the radome, it is required to be quite small compared to the inner diameter of the radome, so the antenna gain 441 can also be suppressed in the 4-14 structure shown in FIGS. 1 and 2. This is a drawback.

(Object of the Invention) In view of the above-mentioned problems in the prior art, an object of the present invention is to provide a directional rotating radome antenna that allows the shape of the antenna to be substantially enlarged within a radome of a fixed size. purpose.

(Structure and operation of the invention) The present invention will be described in detail below. 3 to 6 are structural examples of a directional rotating radome antenna embodying the present invention.

First, FIG. 3 shows the case where the parabolic antenna 1 is used, and the elevation angle]εL rotation is 1I111! The line XX' passes through the space where live radiation occurs in front of the antenna reflecting surface R, and the center point N of the maximum outer diameter QQ' of the antenna structure (body) is close to the center of antenna rotation O. 7. As a result, the diameter of the antenna reflecting surface accommodated within the radome can be made much larger than in the Sono 1 device. Since the gain of the parabolic antenna is proportional to the aperture surface I of the reflecting surface, the antenna gain of FIG. 3 can be increased by 2 to 3 dB compared to the conventional antenna of FIG.

As can be seen from Fig. 3 and Fig. 5, which is a cross-sectional view thereof, the transmitting/receiving amplifier A is mounted on the back side of the reflecting surface of the antenna near the rotation support frame S, and its weight is balanced with respect to the rotation axis. Admonish with a structure that maintains. FIG. 3 shows an example in which the elevation angle EL of the antenna is changed by rotating the pulley F by the friction of the pulley F or the string W. M is a drive unit that provides these rotational forces.

Next, FIG. 4 is a structural example of another radome antenna, and is a front view showing a state in which four helical antennas are housed inside a radome D having the same size as that in FIG. Figure 4
Comparing each antenna radiating element with the one in FIG. 2, it can be seen that the length of the antenna is sufficiently long and the number of windings is large. Since the gain of a helican antenna is proportional to the number of turns, the antenna gain of such a structure can be increased by about 3 dB compared to the conventional structure as shown in FIG.

Similarly to the example in 1-13, the example in Fig. 4 also has an elevation angle El■, a rotation axis
X' passes through the space in front of the reflecting surface R' that produces the main radiation, and the center point N of the maximum outer diameter of the antenna structure coincides with the center point O of the radome. In this case, N is the center point of a sphere circumscribing the antenna structure. The communication amplifier A connected to the antenna is housed in a rectangular tube T at the center of the antenna, as seen in FIG. 4 and FIG. 6, which is a cross-sectional view of FIG. This rectangular tube T is a holding stand for the helical antenna, and also serves as a support stand for holding the rotation i1#l+XX'. The antenna rotation mechanism in FIG. 4 is -
As an example, a case is shown in which the reflection plate is rotated by a gear wheel or a pulley F attached to the central part of the back side of the reflection plate. Further, the square metal tube T disposed at the center of the helical antenna is symmetrical with respect to the center 0 of each antenna element, as shown in FIG. 6, so that the antenna radiation characteristics are not particularly deteriorated.

In the example in Figure 1, the two rotation axes each pass through the center of the antenna system, and both axes intersect at one point O, but in the case of XY-axis rotation, the two axes do not intersect at one point but are close to each other. Sometimes it is done.

The above explanations illustrated with reference to FIGS. 3 to 6 also show the case where the rotational axes of two antennas intersect at one point, but in general, as mentioned above, just because multiple axes are close together does not necessarily mean that they intersect. In the present invention, the intersection point or closest point of the rotation axes of multiple antennas is located in the space on the antenna main radiation side with respect to the antenna reflection surface, and the center of the maximum outer diameter of the antenna structure (QQ'' in FIG. 4) It is characterized in that the center of the sphere circumscribing the antenna structure coincides with or is close to the center of the hemispherical portion of the radome.

In the above explanation, the case where the Az axis and the EL axis are used has been explained. However, in general, the rotation in the directional space of the satellite communication antenna is as follows: i Az (azimuth angle),
In addition to the two-axis rotation of EL (elevation angle), X- and Y-axis rotations, or a rotation system of a few axes based on a combination thereof, are used, and the present invention is similarly applicable to these.

(Effects of the Invention) As is clear from the above description, according to the present invention, it is possible to accommodate a larger high-gain antenna than ever before in a radome of a certain size. In other words, when the gain of an antenna is given, the size of the radome that houses the antenna can be made smaller than that of conventional ones, which makes handling and mounting (ifiii force 1j) simpler, and furthermore, the cost is lower. The rotational directional radome 7 sotenas can be realized, which is the ultimate practical effect.

[Brief explanation of drawings]

1 and 2 are front views including cross sections showing structural examples of conventional rotary directional radome antennas using a parabolic antenna and four helical antennas, respectively, and FIGS. 3 and 4 show rotary directional radome antennas according to the present invention The first part of the radome antenna
4. Parabola is an example. 5 is a cross-sectional view of the embodiment shown in FIG. 3, and FIG. 6 is a cross-sectional view of the commercial example shown in FIG. 4. It is. 1... Antenna, A... Transmitting/receiving amplifier, B...
・Azimuth angle Az rotary table, C...Support frame, D...Radome, E...Rotation mechanism, EL...Elevation angle, M...Driver, N...Maximum outside of antenna structure (body) Center point of diameter, 0...Center point of antenna rotation, P...Radiator of parabolic antenna, P1-P4...Helical antenna element, R, R'...Antenna reflection surface, S...Rotation Support frame, T... Square tube, XX'... EL rotation axis of the antenna, ZZ'... Azimuth angle A2 rotation axis of the antenna. Patent applicant International Telecommunications Facility Co., Ltd. agent Hibaku 1 person outside the university Figure I Z Z゛Figure 2 Figure 3 Figure 4 Figure 6 Figure 5 Procedural amendment (voluntary) April 17, 1980 Commissioner of the Patent Office Mr. Kazuo Wakasugi 1. Indication of the case Patent Application No. 1983-46565 2. Name of the invention Directional rotating radome antenna 3. Person making the amendment Relationship to the case Applicant International Communication Facility Co., Ltd. 4, Agent 1 Nishi-Shinjuku, Shinjuku-ku, Tokyo -23-1 ■ Correction of the specification (1) Delete page 7, line 14 [-1 The birthmark is a pulley]. (2) Correct [F] in line 15 of the same page to [F']. (3) Correct page 8, line 11 [Figure 4] to [Figure 3]. (4) After page 10, line 3 [amplifier,] (Az...
・Insert azimuth, ]. (5) In the fourth line of the same page, correct [Azimuth angle A2 rotary table] to [Azimuth angle rotary table]. (6) After the fifth line of the same page [elevation angle,] [F...pulley, F
′...gear, ] is not inserted. ■ Correction of drawings Figures 3 and 4 should be corrected as shown in the attached sheet.

Claims (1)

[Claims] The closest point or intersection point of the antenna's multiple rotations Tiq1t is the sky I on the front side with respect to the antenna anti-4jilI4.
It is special that the antenna radiation system is located at L+j and that the diameter of the antenna radiation system or the center point of the circumscribed sphere is arranged so that it is located in the middle of the radome surrounding the antenna (close to or coincides with). 'Directional rotating radome antenna.