JPS5945282B2 - ball lens antenna - Google Patents

Description

[Detailed Description of the Invention] This invention is constructed by arranging a plurality of element antennas,
The present invention also relates to a spherical lens antenna that performs beam scanning by attaching a spherical lens to an electronic scanning array antenna that scans an electronic beam.

First, a conventional antenna of this type will be briefly explained.

FIG. 1 is a vertical cross-sectional view of a conventional spherical lens antenna, which is rotationally symmetrical about its centerline 1. FIG.

2 is an electronic scanning array antenna made by arranging a plurality of primary transmitting element antennas 3 in a plane, and each primary transmitting element antenna 3 is equipped with a variable phase shifter 4 and a variable phase shifter 4 for controlling the feeding phase. A primary receiving element antenna 5 for receiving power supplied through space is connected.

Reference numeral 6 denotes a phase amount quantization control circuit for controlling the variable phase shifter 4.

7 is a plurality of secondary reception element antennas for receiving the radiation beam from the electronic scanning array antenna 2, and 8 is a plurality of secondary transmission element antennas 9 for directing the beams radiated from the antenna in a certain desired direction. Fixed phase shifter for directing to 10
11 is a lens element composed of a secondary receiving element antenna 7, a fixed phase shifter 8, and a secondary transmitting element antenna 9;
is a spherical lens made up of a plurality of lens elements 10, and 12 is a central ray emitted from the center point M of the electronic scanning array antenna 2, which represents the propagation force of the beam in one direction.

Reference numeral 13 denotes a power distribution primary radiator that distributes and supplies power to the electronic scanning array antenna 2 through space.

14 is a transmission source that supplies power to the primary radiator 13 for power distribution.

The spherical lens 11 is hemispherical, and the directivity of the secondary reception element antenna 7 and the secondary transmission element antenna 9 that constitute the lens element 10 is approximately C08nφ□(n;
A positive real number, φ; angle from the main radiation direction), is used, and the main radiation direction (direction of maximum radiation; φ-〇) is on the - straight line, and the main radiation direction is the direction of the electronic scanning array antenna 2. is facing the center point M.

Since this spherical lens antenna is constructed as described above, 1. The radiated power from the power distribution primary radiator 13 is received by each primary receiving element antenna 5 of the electronic scanning array antenna 2 and reaches the variable phase shifter 4.

Then, the variable phase shifter 4 is controlled by the phase amount quantization control circuit 6, and the relative feeding phase of each primary transmitting element antenna 3 is changed, so that the direction of the radiation beam from the electronic scanning array antenna 2 is changed. Change.

At this time, the secondary receiving element antenna 7 receives the radiation beam from the electronic scanning array antenna 2, and the received radio wave undergoes a phase change by the fixed phase shifter 8, and the secondary transmitting element antenna 7 receives the radiation beam from the electronic scanning array antenna 2. 9 and is emitted to the space outside the spherical lens 11.

Incidentally, in order to obtain a radiation pattern with a low side lobe, the amplitude distribution at the electronic scanning array antenna 2 is made to have a large amplitude near the center point M, such as a Taylor distribution.

At this time, the bundle of light rays emerging from the vicinity of the center point M has a high density and high energy.

Therefore, when considering the direction of the lens element 10, it is appropriate to focus on the bundle of light rays emitted near the center point M of the electronic scanning array antenna 2.

Hereinafter, the relative positional relationship between the central ray 12 and the lens element 10 will be described with the center ray 12 representing the traveling direction of a bundle of light rays emitted from the vicinity of the center point M of the electronic scanning array antenna 2.

In the conventional spherical lens antenna shown in Fig. 1, θbeta.

In this case, with respect to the lens element 10 that the center ray 12 hits, the secondary receiving element antenna 7 receives waves in the main radiation direction, or
The secondary transmission element antenna 9 is at an angle θ from the broadside.

radiates in a direction other than the main radiation direction.

When the direction of the lens element 10 (coinciding with the main radiation direction) and the angle of incidence and angle of refraction formed by the central ray 12 are equal, the secondary receiving element antenna 7 and the secondary transmitting element antenna 9 having directivity of cosnφ The configured lens element 10 most effectively receives power from the broadside in the angle θ direction,
Since it is easily proven that it radiates in the θ0 direction, the first
In the conventional spherical lens antenna shown in the figure, the lens element 10 effectively receives and does not radiate power, which means that θ.

There was a drawback that the gain in the direction was reduced.

In order to eliminate this drawback, the present invention arranges the lens element so that the direction of the lens element and the angle of incidence and refraction of the central ray are equal.

Furthermore, the spherical lens was shaped so that the incident angle of the central ray with respect to its normal direction was equal, and the lens element was installed so that the direction of the lens element coincided with the normal direction of the spherical lens.

The drawings will be explained in detail below.

FIG. 2 is a vertical sectional view of one embodiment of the invention.

1 to 14 are the same as those in FIG. 15 is an element antenna for secondary reception 7. The angle of incidence and refraction of the line 15 representing the direction of the lens element 10 that coincides with the main radiation direction of the element antenna 9 for secondary transmission and the central ray 12 are equal to θ. .

At this time, this lens element 10 most effectively receives power from the broadside at an angle θ.

radiate in the direction.

Note that when the phase distribution at the spherical lens 11, that is, the phase amount at the plurality of fixed phase shifters 8 is determined, the central ray 1 emitted from the center point M of the electronic scanning array antenna 2
2 is uniquely determined for each scan, and is θ shown in FIG.
.

In the case of different scanning angles, the incident angle and refraction angle formed by the central ray 12 and the line 15 representing the direction of the lens element are determined, and if these angles are made equal, the spherical lens 1
All lens elements 10 at 1 are installed.

FIG. 3 shows another embodiment of the invention, in which 1 to 14 are the same as in FIG. 1, and 15 is the same as in FIG. 2.

Reference numeral 16 denotes a virtual surface of the spherical lens 11 provided between the inner and outer surfaces of the spherical lens 11.

Virtual surface 16 of spherical lens and electronic scanning array antenna 2
Among the distances from the center point M, the distance at the broadside is R8, and the distance from the broadside in the angle θ direction is Rρ
), the shape of the virtual surface 16 of the spherical lens is given by:

θ and θ. is connected by the following formula. θ=K(θ)θ
(2) However, K(θ) is the spherical lens 1
This is a quantity related to the phase distribution at 1.

When the shape of the virtual surface 16 of the spherical lens is given by the first equation, a line 15 representing the direction of the lens element in the normal direction
line 15 representing the direction of the lens element.
The incident angle and the refraction angle formed by the central ray 12 are equal to θ□.

That is, when the lens element 10 is installed perpendicularly to the surface of the spherical lens 11, the lens element 10 most effectively receives power from the broadside in the angle θ direction and radiates it in the θ0 direction.

Note that although the case of transmission has been described above, the present invention may also be used in the case of reception.

Furthermore, although a planar array antenna has been described as the electronically scanned array antenna, the present invention can be similarly implemented in any array shape.

As described above, in this invention, the lens element is installed so that the angle of incidence and refraction between the direction of the lens element and the central ray are equal, or the lens element is installed as a spherical lens so that the angle of incidence of the central ray with respect to its normal direction is The lens element can receive and radiate power most effectively by making the lens element have a shape that has the same refraction angle as , gain reduction can be improved, and the effect is significantly greater when this antenna is used for radar, etc.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a conventional spherical lens antenna, FIG. 2 is a vertical cross-sectional view showing one embodiment of the present invention, and FIG. 3 is a vertical cross-sectional view of another embodiment of the present invention. In the figure, 2 is an electronic scanning array antenna, 3 is an element antenna for primary transmission, 4 is a variable phase shifter, 5 is an element antenna for primary reception, 6 is a phase amount quantization control circuit, and 7 is for secondary reception. element antenna, 8 a fixed phase shifter, 9 an element antenna for secondary transmission, 10 a lens element, 11 a spherical lens, 12 a central ray, 13 a primary radiator for power distribution, 14 a transmission source,
15 is a line representing the direction of the lens element, and 16 is a virtual diagram of a spherical lens. In the drawings, the same or corresponding parts are designated by the same reference numerals.

Claims (1)

[Scope of Claims] 1. An electronically scanned array antenna comprising a plurality of element antennas and a phase shifter provided corresponding to each of the element antennas, and covering the electronically scanned array antenna,
and a spherical lens antenna having a plurality of lens elements, when a central ray emitted from the element antenna at the center of the electronic scanning array antenna enters the spherical lens and is refracted, A spherical lens antenna characterized in that the lens element is set so that the angle of incidence and the angle of refraction with respect to the direction of the lens element are equal. 2. Claim 1, characterized in that the spherical lens has a shape in which the angle of incidence and refraction of the central ray with respect to its projection direction are equal, and the lens element is disposed in the normal direction of the spherical lens. Ball lens antenna described in section.