JPS6326006A - Array antenna with reflection plate - Google Patents

Abstract

PURPOSE:To eliminate the leakage of a radio wave from a gap between small reflection plates by constituting the titled reflection plate by square-shaped small reflection plates provided corresponding to each radiation element and providing bent plates to the entire circumference of a side at an edge of each small reflection plate or a part of the side while being prolonged in a direction opposite to the radiation element. CONSTITUTION:The small reflection plate 1 is folded in a direction opposite to the direction of dipoles 2a, 2b and then prolonged in the folded direction at the peripheral of the small reflection plate 1 corresponding to each split radiation element. Caption (l) is a length of folded plates 6a, 6b, 7a, 7b. Captions 3a, 3b, 4a, 4b are gaps with adjacent small reflection plates. The edge sides of the small reflection plate 1 are short-circuited electrically each edge side of adjacent surrounding small reflection plates 1 and the same radiation characteristic of an array antenna as the case with using one large reflecting plate in common is obtained. Thus, the electrically equivalent state to the configuration of a large reflection plate is obtained by the structure of split small reflection plates.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an array antenna with a reflector in which the end sides of the reflector are bent in order to eliminate the adverse electrical effects caused by the gaps between the divided reflectors.

[Conventional technology]

When the radiation space is made into a half space with an array antenna, a radiation element with a reflector is generally used as a radiation element, and a large reflection plate is used as the reflection plate and is shared by each radiation element. However, if each radiating element is integrated with each rear module in an active phase array antenna, etc. to create a structure that can be replaced in the event of a failure, the above reflector needs to be divided into small reflectors for each radiating element. There is.

Figure 4 is a structural diagram of a conventional split-type reflector-equipped array antenna using a reflector-equipped dipole, as shown, for example, in the Antenna Engineering Handbook, edited by the Institute of Electronics and Communication Engineers, Ohmsha (1980-10), p. 49. (1) is a small reflector using a metal conductor plate, (2a) and (2b) are diepo.

- (3a), (8b), (4a), (4b) are gaps, and (5) is a dipole with a reflector. FIG. 5 is a diagram showing the current on the reflector of the radiating element of the conventional array antenna with reflector shown in FIG. 4 and the electric field in the gap. In Fig. 5, when power is supplied to the dipoles (2a) and (2b), a current flows on the small reflector (1) in the direction of the arrow shown by A, and since the small reflector (1) is divided, there is a gap between R(4
a).

A voltage is generated at (4b). Gaps (3a), (3b), (
4a) and (4b) form annular slots, and when an electric field is generated in the gaps (4a) and (4b), this annular slot is excited.

[Problem that the invention seeks to solve]

When the annular slot is excited as described above, the circumference of the annular slot resonates at a frequency that is an integral multiple of the 05 wavelength,
Since it operates as an antenna and radiates radio waves, there is a problem in that it deteriorates the radiation characteristics such as the radiation pattern and impedance of the dipoles (2a) and (2b). Also, since the small reflector (1) cannot be said to be electrically large enough compared to the wavelength, a design method is generally applied that assumes the reflector is infinite and determines the dimensions, height, etc. of the dipoles (2a) and (2b). There were also problems such as not being able to do so.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain an array antenna with a reflector that is equivalent to one using a large reflector by bending the edges of a small reflector. .

[Means for solving problems]

In the array antenna with a reflector according to the present invention, the small reflector (1) is bent in the opposite direction to the dipoles (2a) and (2b) at the outer periphery of the divided small reflector (1) corresponding to each radiating element. It is stretched out.

[Effect]

By appropriately selecting the lengths of adjacent bent portions of the small reflectors in this invention, each reflector is short-circuited and becomes equivalent to a large reflector corresponding to the number of elements.

〔Example〕

An embodiment of this invention will be described below. In Fig. 1, (1) is a small reflector, (2a) and (21a) are dipoles, (6a) and (6b) are bent plates on the short sides of the small reflector (1), and (7a).

(7b) is a bent portion of the long side of the small reflective plate (1). l
are bent plates (6a), (6b), (7a), (7b)
is the length of Figure 2 is a diagram showing the structure when the Gouipole with reflector plate shown in Figure 1 is arranged, (3a), (3b).
, (4a) and (4b) are the gaps between adjacent small reflectors.

In Figure 2, between! The impedance ZS of the parallel plate line formed by the bent plates (7a) and (7b), which are parallel flat plates when viewed from the rear from 'lX <88), is expressed by the following equation.

However, ZO+ is the characteristic impedance of the parallel plate line, and ^ is the wavelength. The impedance seen rearward from the gap (3b) is also Zsl in equation [1]. Similarly, gap (4a)
.

The impedance ZS2 seen from the rear from (4b) is ZO□
If is the characteristic impedance of the parallel plate line, it is expressed by the following equation.

In the formula [1'l), Cal, if l = ^/4, ZS+ '' ZS2 = 0 -----
(8:]. In other words, the edge of the small reflector (1) is electrically short-circuited with each edge of the adjacent small reflector (1), and one large reflector is shared. The same radiation characteristics as an array antenna can be obtained.

FIG. 3 is a diagram showing another embodiment of this invention, (1)
(2a), (2b) are dipoles, (7a) are small reflectors, (2a) and (2b) are dipoles, (7a
) and (7b) are bent plates on the long sides of the small reflective plate (1). With this structure of the reflector, it is possible to make the annular slot non-resonant by short-circuiting the long sides of the excited annular slot, so it can be used as an electrically equivalent array antenna with a reflector shown in Figure 2. One large reflective plate is obtained.

Although the above description has been made regarding the case where a Goupole with a reflector is used as the radiating element, the same can be applied to the case where a loop with a reflector, a slot, or a microstrip antenna is used.

〔Effect of the invention〕

As explained above, according to the present invention, the electrically equivalent state of one large reflector can be obtained with the structure of separated small reflectors, which facilitates the design and operation of an array antenna with divided reflectors. This has a significant effect in reducing the time it takes to replace modules.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of a divided small reflector of an array antenna with a reflector according to the present invention, Fig. 2 is a partial structural diagram of this array antenna with a temporary projection, and Fig. 3 is a structural diagram of another embodiment of the present invention. FIG. 4 is a structural diagram of a conventional array antenna with a reflector, and FIG. 5 is a partial structural diagram. In the figure, (1) is a small reflector, (2a), (2b) dipoles, (3a), (8b), (4a), (4b) are gaps,
(6a), (6b), (7a), and (7b) are bent plates. In addition, the same reference numerals are given to the same or corresponding parts in the figures. Patent Applicant: Toru Yamashita, Director, Technical Research Headquarters, Defense Agency Figure 1 Io, 1 tilting technique, 2b, 7゛ water level 4 "6": Pile mill handling 7υ, 7b Figure 4 Figure 5

Claims (1)

[Claims] In an array antenna with a reflector in which a plurality of radiating elements are arranged on one side of a reflector which is a metal conductor plate, the reflector is composed of small rectangular reflectors provided corresponding to each radiator. A bent plate is provided around the entire circumference or a part of the edge of the small reflector plate, extending in the opposite direction to the radiating element, and the length of the bent plate is set to be about 1/4 wavelength of the operating frequency. An array antenna with a reflector, characterized in that the small reflectors are electrically short-circuited to eliminate leakage of radio waves from gaps between the small reflectors.