JP3718281B2 - Radar antenna - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small-sized radar antenna that is mounted on, for example, a ship and is rotatably accommodated in a circular radome.
[0002]
[Prior art]
Usually, a radar irradiates a target with radio waves, receives a reflected wave from the target, and determines the position of the target from the relationship between the round-trip time and the antenna directivity.
[0003]
FIG. 7 is a diagram showing a configuration of a transmitter / receiver unit of a radar antenna using a circulator. A transmission signal from the magnetron in the transmitter is transmitted from the transmission port A of the circulator to the antenna port B, and is irradiated from the antenna via the rotary coupler. The reception signal obtained by reflecting the transmission signal irradiated from the antenna by the target is introduced from the antenna port B of the circulator to the reception port C via the rotary coupler. A limiter is normally connected between the receiving port C and the front end of the receiver.
[0004]
[Problems to be solved by the invention]
Conventionally, the magnetron, the front end, and the limiter are components that are individually fixed to the end face of the waveguide portion, and each must be removed separately during maintenance and assembly. In navigation equipment such as radar scanners, maintenance work is performed in an unstable place such as a mast on a ship. For this reason, it has been difficult to find the failure location with a single component.
[0005]
The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a radar antenna having a structure in which a transmitter / receiver unit including a magnetron, a front end, a limiter, and a printed circuit board can be integrally removed. To do.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the radar antenna according to the present invention has the constitutions (1) to (3). (1) The arrangement of the magnetron, limiter front end and printed circuit board is U-shaped. {Circle around (2)} Dividing into two units: a base on which a waveguide through which radio waves pass is arranged and a chassis on which a printed circuit board, a magnetron, and a limiter front end are arranged. (3) A choke is provided on the end face on the waveguide side where the magnetron and the waveguide, and the limiter front end and the waveguide are joined.
[0007]
Specifically, in claim 1, an antenna 1 that radiates radio waves, a base 5 that supports the antenna, and a transmitter / receiver unit that is mounted between the antenna 1 and the base 5 and that transmits and receives radio waves. 20 and a radar radome 4 that houses the antenna 1 , the base 5, and the transmitter / receiver unit 20 , the transmitter / receiver unit 20 includes a magnetron 21 that transmits radio waves and a limiter front end that receives radio waves. and 22, a printed circuit board 23 mounted with the interface circuit for the magnetron 21 and the limiter front end 22, a U-shape, and arranged on the same chassis 24, the chassis 24 is attached to the base 5 the upper waveguiding A lower waveguide (32) is attached to the lower part of the pipe part (31), and the base (5) and the lower waveguide are attached to the lower part of the base (5). A waveguide is formed with the tube (32).
[0008]
According to a second aspect of the present invention, in addition to the first aspect, in order to join the waveguide formed at the lower part of the base to the magnetron and the front end of the limiter, the base includes a waveguide portion, and the waveguide Choke was provided on the end face of the part.
[0009]
With the configuration {circle around (1)}, the transmitter / receiver unit can be removed without causing a problem with the main shaft that rises vertically from the lower waveguide unit and supplies radio waves to the antenna. Also, with the configuration (2), the base and the chassis can be separated from each other. Furthermore, with the configuration (3), the magnetron and the limiter front end need not be directly fixed to the waveguide.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a conceptual diagram showing an example of removing a chassis on which a printed circuit board, a magnetron, and a limiter front end are arranged. FIG. 2 is a conceptual diagram in which each part is extracted. 3 is a plan view of the radar antenna, FIG. 4 is a cross-sectional view taken along the line AA in the state with the cover of FIG. 3, and FIG. 5 is a cross-sectional view taken along the line BB in the state with the cover of FIG. FIG. 6 is a diagram of the junction between the magnetron or limiter front end and the waveguide section.
[0011]
First, an embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, and FIG. The transmitter / receiver unit 20 includes a magnetron 21, a limiter front end 22, and a printed board 23 (not shown) accommodated in a shield case, which are disposed on the chassis 24. Each of these components is arranged in a U shape.
[0012]
The base 5 has a rotating shaft 6 and a waveguide portion 31. The rotating shaft 6 is provided with an antenna 1 having a primary radiator 3. A motor 12 for rotating the antenna 1 is attached to the base 5. A lower waveguide 32 for guiding radio waves is attached to the lower part of the waveguide portion 31.
[0013]
The base 5 is fixedly attached to the bottom radome 4b. The transmitter / receiver unit 20 is attached to the base 5 using the screw hole 5b and the screw hole 24a. That is, the magnetron 21, the limiter front end 22, and the printed circuit board 23 are components fixed on the same chassis 24 to the end face of the waveguide portion, and therefore can be removed at the time of maintenance and assembly (see FIG. 1 dotted arrow). Therefore, in navigation equipment such as a radar scanner, maintenance work can be easily replaced at an unstable place such as a mast on a ship.
[0014]
As shown in FIG. 6, the magnetron 21 and the lower surface of the limiter front end 22 are choke joined by a choke 31 a of the waveguide portion 31.
[0015]
Next, the structure and operation of the radar antenna will be described with reference to FIG. 3, FIG. 4, and FIG. The radar antenna according to this embodiment is used, for example, as a marine radar, and a reflector 2 and a primary radiator 3 constituting the antenna 1 are rotatably accommodated in a radome 4.
[0016]
The radome 4 has a substantially cylindrical shape with a hollow inside, and includes a cover 4a and a bottom base 4b that are vertically divided into two. The cover 4a and the bottom base 4b are detachably fixed via fixing means such as screws and bolts. Although not shown, the radome 4 has a structure in which a waterproof packing is provided along the entire periphery of the edge of the bottom base 4b, and the joint portion with the cover 4a is waterproofed.
[0017]
A base 5 made of, for example, an alloy, which rotatably supports the antenna 1 is attached to the bottom base 4b. A cylindrical support cylinder 5a is integrally formed at the center portion of the base 5 so as to extend in a direction perpendicular to the horizontal plane 4ba of the bottom base 4b.
[0018]
A rotating shaft 6 is inserted into the support cylinder 5a of the base 5 with one end rotatably supported on the horizontal surface 4ba of the bottom base 4b. The rotating shaft 6 has a cylindrical shape, and a rectangular through hole 6a forming a waveguide is formed therein. The central portion of the outer periphery of the rotary shaft 6 has a large diameter portion 6b, and a small diameter portion 6c having the same diameter slightly smaller than the large diameter portion 6b is formed above and below the large diameter portion 6b. A bearing 7 is fitted and fixed to the outer periphery of the rotary shaft 6 in a state where the bearing 7 is in contact with the step portion 8 between the upper and lower small diameter portions 6c and 6b.
[0019]
The reflector 2 converts a radio wave irradiated from a radio source (not shown) through the primary radiator 3 into a plane wave and radiates it toward the target. The reflecting plate 2 uses a part of a parabolic surface 9 including a vertex P of a rotating parabola formed by rotating a parabola as a radiation surface 2a.
[0020]
In the reflector 2, the rotation center line L <b> 1-L <b> 1 where the apex P is located coincides with the phase center of the radio wave in the opening 3 a of the primary radiator 3 described later. The reflecting plate 2 is fixed to the primary radiator 3 by a fixing means 16 such as a screw via the mounting portion 15 so that the focal point of the radiation surface 2a coincides with the phase center of the primary radiator 3.
[0021]
The primary radiator 3 is fixed to the rotating shaft 6 by fixing means 17 such as screws. A flat flange 10 is integrally formed on the lower outer peripheral surface of the primary radiator 3. Teeth 11 a are formed on the outer peripheral surface of the flange 10 over the entire circumference, and constitute a transmission gear 11. The transmission gear 11 meshes with the motor gear 13 of the motor 12 fixed to the base 5. When the power of the motor 12 is transmitted to the transmission gear 11 via the motor gear 13, the primary radiator 3 rotates around the rotation shaft 6 together with the reflector 2.
[0022]
In the radar antenna having the above configuration, when a radio wave is irradiated from the primary radiator 3 to the reflecting plate 2 as the antenna 1 rotates, the radio wave is reflected by the reflecting plate 2 and radiated toward the target. A predetermined detection process for determining the position of the target from the relationship between the reflected wave from the target, the round-trip time, and the antenna directivity is executed by irradiating the target with radio waves.
[0023]
【The invention's effect】
As described above, in the radar antenna, the magnetron 21, the limiter front end 22, and the printed circuit board 23 are components fixed on the same chassis 24 to the end face of the waveguide portion. Further, since the waveguide is formed below the base 5, the waveguide and the waveguide section 31 are fixed to the base 5 even when the transmitter / receiver section 20 is detached from the base 5. Therefore, the magnetron 21, the limiter front end 22 and the printed board 23 can be removed at the same time during maintenance and assembly. Furthermore, in navigation equipment such as a radar scanner, maintenance work can be easily replaced at an unstable place such as a mast on a ship. Furthermore, since the waveguide is integrally formed with the base 5 at the lower part of the base 5, the number of parts can be reduced and the assembly can be simplified.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram for explaining the concept of the present invention.
FIG. 2 is a conceptual diagram in which each part of FIG. 1 is extracted.
FIG. 3 is a plan view of a radar antenna.
4 is a cross-sectional view taken along line AA with the cover of FIG.
5 is a cross-sectional view taken along the line BB in a state where the cover of FIG. 3 is present.
FIG. 6 is a cross-sectional view of a joint portion between a magnetron or limiter front end and a waveguide portion.
FIG. 7 is a block diagram of a radar antenna transmitter / receiver using a circulator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Antenna, 4 ... Radar radome, 5 ... Base, 20 ... Transmitter / receiver part, 21 ... Magnetron, 22 ... Limiter front end, 23 ... Printed circuit board, 24 ... Chassis, 31 ... Waveguide part, 31a ... Choke.

Claims (2)

An antenna (1) that emits radio waves, a base (5) that supports the antenna, and a transmitter / receiver unit (20 ) that is mounted between the antenna (1) and the base (5) and that transmits and receives radio waves. ) and the antenna (1), in the radar antenna and a radar radome (4) for accommodating the base (5) and the transmitting and receiving device section (20),
The transmitter / receiver unit (20) includes a magnetron (21) for transmitting radio waves, a limiter front end (22) for receiving radio waves, and a print on which an interface circuit for the magnetron (21) and the limiter front end (22) is mounted. and that the substrate (23), the U-shape, and arranged on the same chassis (24),
The chassis (24) is mounted on top of the base (5);
Attaching a lower waveguide (32) to the lower part of the waveguide part (31) and forming a waveguide with the base (5) and the lower waveguide (32) at the lower part of the base (5) ;
Radar antenna characterized by. In order to join the waveguide formed in the lower part of the base (5) to the magnetron (21) and the limiter front end (22) , a choke is provided on the end face of the waveguide section (31). The radar antenna according to claim 1.

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