JP2009200704A - Excitation method of array antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excitation method of an array antenna which reducesa a time duration and the number of connecting elements for creation of a beam forming. <P>SOLUTION: In the excitation method of the array antenna composed of a plurality of element antennas arranged in a two dimensional shape as a primary radiator of a reflection mirror, and an amplitude controller and a phase shifter connected to respective element antennas, the method has: a step S1 of selecting the element antennas in a range that a parallel ray from a desired beam direction is reflected with a contoured shape of a mirror plane of the reflection mirror, and projected on the array antenna face; a step S2 of obtaining an excitation amplitude and an excitation phase of the selected element antennas so that a gain in the desired beam direction becomes maximum; a step S3 of establishing the obtained excitation phase in the phase shifter while establishing the obtained excitation amplitude in the amplitude controller; and a step S4 of connecting the selected element antennas to a transceiver. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an array antenna excitation method used as a primary radiator of a reflector antenna.

  In a conventional array-fed reflector antenna, in order to obtain a beam in a desired direction, it is necessary to set an appropriate excitation amplitude and excitation phase for each element antenna constituting the array antenna. In order to operate the connected amplifier efficiently, the excitation amplitude is often limited to several discrete levels instead of continuous, considering the saturation output amplifier, and the excitation phase depends on the desired beam direction. Determine numerically so that Conventionally, the excitation phase or excitation amplitude phase of all array elements has been numerically determined so as to form a beam in a desired direction (see, for example, Non-Patent Document 1).

IEICE Transactions B, vol. J82-B, No.7, pp.1357-1365, “Electric Design and Prototype of Phased Array Feeder for Satellite Reflector Antenna”, Tokunaga et al.

  In the conventional method of exciting the reflector antenna feed array, the excitation amplitude and phase of all elements are determined numerically as described above, and therefore it takes a lot of calculation time when the number of elements is very large. There is. In particular, it becomes a problem when the beam is dynamically formed by an on-board processor mounted on the satellite. In addition, since all the elements are used to form the beam in each desired direction, it is necessary to connect the transmitter / receiver to all the elements, which causes a problem of complicated connection.

  Also, if the number of elements is limited in order to shorten the calculation time or reduce the number of connected elements, depending on the number of elements reduced, the antenna performance such as antenna gain in the desired direction may be affected. Therefore, it is necessary to optimize the numerical excitation amplitude.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an array antenna excitation method capable of reducing the time for beam formation and the number of connected elements.

  An array antenna excitation method according to the present invention includes a plurality of element antennas arranged two-dimensionally as a primary radiator of a reflector, an amplitude controller connected to each element antenna, and a phase shifter. In the method for exciting an antenna, a step of selecting an element antenna in a range in which parallel rays from a desired beam direction are reflected by the mirror surface contour of the reflector and projected onto the array antenna surface, and gain in the desired beam direction is selected. And obtaining the excitation amplitude and excitation phase of the selected element antenna, setting the obtained excitation amplitude in the amplitude controller, and setting the obtained excitation phase in the phase shifter And a step of connecting the selected element antenna to a transceiver.

  According to the present invention, an element in a range where parallel rays from a desired beam direction are reflected by the contour of the mirror surface and projected onto the array antenna surface is selected, and the selection is performed so that the gain is maximized in the desired beam direction. By obtaining the excitation amplitude phase of the selected element numerically and setting the excitation amplitude phase to each element antenna, a beam in a desired direction can be formed in a short time, and the number of elements connected to the transceiver is reduced. is there.

  The present invention selects an element in a range in which parallel rays from a desired beam direction are reflected by the contour of the mirror surface and projected onto the array antenna surface, and the selected element so that the gain is maximized in the desired beam direction. Is obtained numerically. Hereinafter, illustrated embodiments will be described.

Embodiment 1 FIG.
1 and 2 are diagrams for explaining an array antenna excitation method according to Embodiment 1 of the present invention, and FIG. 1 shows calculation of excitation amplitude and excitation phase of the array antenna according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram of an antenna for explaining a method for determining a selection element range according to the present invention. The first embodiment of the present invention will be described below along the flowchart shown in FIG. 1 with reference to FIG.

  First, in step S1 shown in FIG. 1, an element to be excited is determined. In the first embodiment of the present invention, elements in a range where parallel rays from a desired direction are reflected by the contour of the mirror surface and projected onto the surface of the array antenna are selected. For example, as shown in FIG. 2, a parallel light beam 15 from a desired direction is reflected by a mirror surface contour 19 to become a light beam 15a, and an element 16 in a range 14 surrounded by points intersecting the surface of the array antenna 12 is selected. To do. At this time, since the light beam is reflected in the direction determined only by the law of reflection and does not include the wave effect, the element range can be determined in a very short time.

  Next, in step S2, the excitation amplitude and the excitation phase of the selected element are determined. The excitation amplitude and excitation phase of each array element are determined numerically so that the gain is maximized in the desired beam direction. Compared to determining the excitation amplitude and excitation phase of all the conventional elements, the excitation amplitude and excitation phase for a beam in a desired direction are determined in a short time in order to determine the excitation amplitude and excitation phase of a limited range of elements. be able to.

  Next, in step S3, the obtained excitation amplitude is set in the amplitude controller 33 shown in FIG. 2, and the obtained excitation phase is set in the phase shifter 32 also shown in FIG. A beam is formed. The amplitude controller 33 may be an attenuator or an amplifier.

  Next, in step S4, the element 16 selected in step S1 is connected to the transceiver 31 with a switch or the like. At this time, all the elements selected in step S1 including elements having a small excitation amplitude determined in step S2 may be connected, or the number of connected elements may be reduced except for elements having a small excitation amplitude.

  Therefore, according to the first embodiment, an element in a range in which parallel rays from a desired beam direction are reflected by the contour of the mirror surface and projected onto the array antenna surface is selected, and the gain is maximized in the desired beam direction. Thus, the number of elements connected to the transceiver can be formed in a short time by obtaining the excitation amplitude phase of the selected element numerically and setting the excitation amplitude phase to each element antenna in a short time. Is effective.

Embodiment 2. FIG.
FIG. 3 is a configuration diagram of an antenna according to Embodiment 2 of the present invention. In FIG. 2, the element antennas of the array antenna 12 are arranged in a curved shape, but the element antenna of the array antenna 12 may be a planar array antenna as shown in FIG. In FIG. 3, an array antenna directed to the center of the mirror surface is shown. However, if the parallel light beam 15a from a desired direction is reflected by the mirror surface and the array antenna surface intersects, the directivity direction of the array antenna is arbitrary. It is.

Embodiment 3 FIG.
4 is a block diagram of an antenna according to Embodiment 3 of the present invention. In Embodiment 3 shown in FIG. 4, the reflecting mirror is a parabolic reflecting mirror (rotating paraboloid) 11a. Although FIG. 4 shows the offset parabolic reflector 11a, an axially symmetric parabola may be used. As shown in FIG. 4, when the reflecting mirror is a parabolic reflecting mirror 11a, the parallel light beam 15 from the desired direction is focused at a focal point 17 at one point. Compared with the case of a plane reflecting mirror, the light rays 15a from a desired direction are converged, so that the area of the element range 14 is reduced, and the number of elements (number of selected elements) 16 included in the range is also reduced.

  In FIG. 4, the array antenna 12 is flat and is directed toward the center of the parabolic reflector 11a. However, the parallel light 15 from the desired direction is reflected by the mirror surface and the array antenna surface is the same. As long as they intersect, it may be in an arbitrary curved direction and in an arbitrary directivity direction.

Embodiment 4 FIG.
FIG. 5 is a block diagram of an antenna according to Embodiment 4 of the present invention. The reflecting mirror is composed of a plurality of rotating quadric curved mirrors. FIG. 5 shows an offset Cassegrain format in which the first mirror surface is a rotating hyperboloidal mirror (sub-reflection mirror) 11b and the second mirror surface is a parabolic reflection mirror 11a as viewed from the primary radiator side. Alternatively, the mirror surface may be composed of another specular system such as a Gregorian format having three or more mirror surfaces. Compared with a single parabolic reflector, the light beam 15a from a desired direction is focused, so that the element range 14 and the number of selected elements 16 are reduced.

  In FIG. 5, the array antenna 12 is flat and is directed toward the center of the first mirror surface 11b. However, the array antenna 12 includes a light beam 15a in which a parallel light beam 15 from a desired direction is reflected by the mirror surface. As long as the surfaces intersect, it may be in any curved direction and in any directivity direction.

Embodiment 5 FIG.
FIG. 6 is a block diagram of an antenna according to Embodiment 5 of the present invention. In the fifth embodiment shown in FIG. 6, the array antenna 12 is arranged closer to the mirror surface than the focal point 17 of the parabolic reflector 11a in the third embodiment shown in FIG. Since the array antenna 12 is separated from the focal point 17 by the defocusing distance 18, the light beam 15a from a desired direction is not focused, and the element range 14 and the selected element range 14 are selected as compared with the case where the array antenna is arranged on the plane including the focal point. The number of selection elements 16 increases. On the other hand, since the change of the element range 14 selected with respect to the beam direction is small, many element antennas are shared when a large number of beams in each direction are formed, and the element antennas of the entire array antenna can be used effectively.

  In FIG. 6, the array antenna 12 is flat and directed toward the center of the parabolic reflector 11a. However, the array antenna surface intersects the light beam 15a in which the parallel light beam 15 from the desired direction is reflected by the mirror surface. In this case, an arbitrary curved surface shape and an arbitrary pointing direction may be used.

Embodiment 6 FIG.
FIG. 7 is a configuration diagram of an antenna according to Embodiment 6 of the present invention. In the sixth embodiment shown in FIG. 7, the array antenna 12 is arranged on the side farther from the mirror surface than the focal point 17 of the parabolic reflector 11a in the third embodiment shown in FIG. The array antenna 12 is separated from the focal point 17 by the defocusing distance 18, and the same effect as in the fifth embodiment can be obtained.

  In FIG. 7, the array antenna 12 is flat and directed toward the center of the parabolic reflector 11a. However, the array antenna surface intersects with the light beam 15a in which the parallel light beam 15 from the desired direction is reflected by the mirror surface. In this case, an arbitrary curved surface shape and an arbitrary pointing direction may be used.

Embodiment 7 FIG.
8 and 9 show the configuration of an antenna according to Embodiment 7 of the present invention. FIG. 8 is a side view, and FIG. 9 is a top view. In the seventh embodiment shown in FIGS. 8 and 9, the array antenna is an array antenna 12 in which element antennas are arranged on a plane as in the second embodiment, and the reflector is a parabolic reflector 11a as in the third embodiment. Further, as in the sixth embodiment, the array antenna 12 is arranged closer to the focal point 17 of the parabolic reflector 11a. In the antenna configuration diagram of FIG. 8, the light beam corresponding to the beam in the upward direction of the antenna is 21, the light beam corresponding to the downward direction is 22, the light beam corresponding to the back direction is 23, and the light beam corresponding to the near direction is 24, corresponding to each. Let the light rays reflected by the mirror surface be 21a to 24a. Further, the corresponding element range is indicated by 25a to 28a.

  FIG. 10 shows the element range determined by the method of the present invention on the array antenna surface. For comparison, FIG. 10 shows a point of an excitation element antenna determined by iterative calculation using numerical optimization. Compared to the case where the entire array antenna (all element antennas) is used and the gain is maximized in the desired beam direction, the element antenna excited under the condition that the gain reduction amount is within the allowable value is minimized. Note that 25b indicates a selection element corresponding to the direction of the light beam 21, 26b indicates a selection element corresponding to the direction of the light beam 22, 27b indicates a selection element corresponding to the direction of the light beam 23, and 28b indicates a selection element corresponding to the direction of the light beam 24.

  FIG. 10 shows that the element antenna position obtained by the above method is included in the element range determined by the method of the present invention. Therefore, it can be understood that the excitation amplitude phase of the element antenna in the range according to the method of the present invention may be numerically optimized instead of the all-element antenna, and the excitation amplitude phase of each array element can be determined in a short time.

It is a flowchart which shows the excitation method of the array antenna which concerns on Embodiment 1 of this invention, and shows the calculation method of an excitation amplitude and an excitation phase. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of an antenna for explaining an array antenna excitation method according to Embodiment 1 of the present invention and for explaining a selection element range determination method; It is a block diagram of the antenna which concerns on Embodiment 2 of this invention. It is a block diagram of the antenna which concerns on Embodiment 3 of this invention. It is a block diagram of the antenna which concerns on Embodiment 4 of this invention. It is a block diagram of the antenna which concerns on Embodiment 5 of this invention. It is a block diagram of the antenna which concerns on Embodiment 6 of this invention. It is a side view of the structure of the antenna which concerns on Embodiment 7 of this invention. It is a top view of the structure of the antenna which concerns on Embodiment 7 of this invention. It is a figure which compares and shows the element range determined by the method concerning Embodiment 7 of this invention, and the element range determined numerically.

Explanation of symbols

  S1 selecting element, S2 determining excitation amplitude and excitation phase, S3 setting excitation amplitude and excitation phase, S4 connecting selected element to the transceiver, 11 reflector, 11a parabolic reflector, 11b Rotating hyperboloidal reflector (sub-reflector), 12 array antenna, 13 element antenna, 14 selection element range, 15 parallel light beam from desired direction, 15a light beam reflected by mirror surface and heading to array antenna, 15b next reflector mirror surface , 16 selected elements, 17 focus of parabolic reflector, 17a focus of rotating quadratic reflector, 18 defocus distance, 21 parallel rays from above antenna of FIG. 9, 22 below antenna of FIG. Parallel rays from the direction, 23 Parallel rays from the back of the antenna in FIG. 9, 24 Front direction of the antenna in FIG. Parallel light, 21a light 21 reflected by the mirror surface and directed to the array antenna, 22a light 22 reflected by the mirror surface and directed to the array antenna, 23a light 23 reflected by the mirror surface and directed to the array antenna, 24a Ray 24 reflected from the mirror surface toward the array antenna, 25a Selection element range corresponding to light 21 direction, 26a Selection element range corresponding to light 22 direction, 27a Selection element range corresponding to light 23 direction, 28a light ray Selection element range corresponding to 24 directions, selection element corresponding to 25b light beam 21 direction, selection element corresponding to 26b light beam 22 direction, selection element corresponding to 27b light beam 23 direction, selection element corresponding to 28b light beam 24 direction, 31 Transmitter / receiver, 32 phase shifter, 33 amplitude controller.

Claims (7)

In an excitation method for an array antenna composed of a plurality of element antennas arranged two-dimensionally as a primary radiator of a reflector, an amplitude controller connected to each element antenna, and a phase shifter,
Selecting an element antenna in a range where parallel rays from a desired beam direction are reflected by the mirror surface contour of the reflector and projected onto the array antenna surface;
Obtaining an excitation amplitude and an excitation phase of the selected element antenna so that the gain is maximized in a desired beam direction;
Setting the determined excitation amplitude in the amplitude controller, and setting the determined excitation phase in the phase shifter;
And a step of connecting the selected element antenna to a transceiver. The array antenna excitation method according to claim 1,
An array antenna excitation method, wherein the element antennas of the array antenna are arranged in a curved shape. The array antenna excitation method according to claim 1,
An array antenna excitation method, wherein the element antennas of the array antenna are arranged on a plane. The array antenna excitation method according to claim 1,
The reflector is a parabolic reflector. An array antenna excitation method, wherein: The array antenna excitation method according to claim 1,
The method of exciting an array antenna, wherein the reflecting mirror is composed of a plurality of rotating quadric curved mirrors. The array antenna excitation method according to claim 4 or 5,
The array antenna is arranged closer to the mirror surface than the focal point of the reflecting mirror. The array antenna excitation method according to claim 4 or 5,
The array antenna excitation method, wherein the array antenna is arranged on a side farther from the mirror surface than the focal point of the reflecting mirror.

Images