JPH05110327A - Phased array antenna - Google Patents

Abstract

PURPOSE:To make the area of the antenna small by exciting two antennas simultaneously and synthesizing in the phased array antenna comprising three sub array antennas or more each of which is arranged with plural element antennas. CONSTITUTION:Two feeding points 11,12 are provided to a 1st sub array antenna 1, the sub array antenna 1 and of a 2nd sub array antenna 2 are synthesized by the feeding point 11 and of the sub array antenna 1 and of a 2nd sub array antenna 2 are synthesized by the feeding point 12 and input and output terminals 6,7 of the 2nd sub array antenna 2 and the 3rd sub array antenna 3 are switched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phased array antenna mounted on a moving body or the like.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional phased array antenna. In the figure, 1 is a first sub-array antenna in which microstrip patch antennas 1a are arranged in a plane, and 1b is a microstrip patch antenna 1a.
Is a phase shifter, and 1c is a distribution / synthesis circuit. Similarly, 2 is a second sub array antenna in which microstrip patch antennas 2a are arranged in a plane, 2b is a phase shifter provided in the microstrip patch antenna 2a, and 2c is a distribution / combining circuit. 3 is a third sub-array antenna in which microstrip patch antennas 3a are arranged in a plane, and 3b and 3c are phase shifters and distribution / combining circuits, respectively. 4, 5 and 6 are input / output terminals of the first, second and third sub-array antennas, 7 is a changeover switch for selecting one of the input / output terminals 4, 5 and 6, and 8 is an input / output terminal. ..

Next, the operation will be described. For example, a phased array antenna used for mobile satellite communication for aircraft is required to have a wide beam scanning range and little deterioration in radiation characteristics in the beam scanning range. Regarding the shape, it is desirable to have a low profile along the structure of the moving body as much as possible. When the antenna is shaped along the structure of the moving body in this way, it is necessary to attach the antenna to a wide part of the moving body in order to obtain a wide beam coverage, for example, when the aircraft flies horizontally over the entire upper hemisphere. In order to obtain the beam coverage, it is desirable to provide the beam cover at three positions on the two side surfaces and the upper surface of the airframe. FIG. 3 shows a conventional embodiment including the three antennas. For example, the first sub-array antenna 1 has an upper beam coverage,
The second and third sub-array antennas shall obtain beam coverage on the left and right wing sides, respectively. Generally, in a phased array antenna, when a beam is scanned in a direction in which the angle from the normal to the element antenna array surface increases, the gain decreases and the side lobe level increases. Therefore, the beam coverage of each antenna is limited to the range in which the required radiation characteristics can be obtained even during beam scanning. First
The sub-array antenna is composed of a plurality of microstrip antennas 1a, a phase shifter 1b provided in each patch antenna, and a distribution / combining circuit 1c. When selecting the first sub-array antenna, the changeover switch 7 is used to connect the four terminals. Select.

[0004]

Since the conventional phased array antenna has a configuration in which each subarray antenna is switched and used as described above, each subarray alone can obtain a required radiation characteristic (especially gain and side lobe characteristic). Must be designed. The gain and side lobes of the array antenna generally improve as the area in which the patch antennas are arranged increases. Therefore, the area of each sub-array antenna is increased to obtain the required performance, which imposes a heavy load on the mobile body mounting.

The present invention has been made in order to solve the above problems, and obtains a phased array antenna which can realize the required antenna gain and side lobe characteristics even if it is configured by an array antenna having a relatively small area. The purpose is to

[0006]

A phased array antenna according to the present invention is provided with two feeding points for a first sub-array antenna of a plurality of sub-array antennas, and an antenna excited at one feeding point and a second feeding point. A new array antenna is formed by combining with the sub array antenna of No. 1 and a new array antenna is formed by combining the sub array antenna excited at the other feeding point and the third array antenna.

[0007]

The phased array antenna according to the present invention is used as an element antenna which constitutes the first sub array antenna.
By providing one feeding point, it is possible to combine the antenna with other antennas and to reduce the size of the antenna as a whole.

[0008]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a first sub-array antenna composed of a microstrip patch antenna 1a, and 1b and 1c are phase shifters connected to the patch antenna 1a,
It is a distribution / synthesis circuit. Similarly, 2a and 3a are microstrip patch antennas, and 2b, 2c, 3b and 3c are phase shifters and distribution / synthesis circuits connected to the patch antennas 2a and 3a, respectively.

Next, the operation will be described. In FIG. 1, the first sub array antenna 1 has two feeding points via a changeover switch 12, and one feeding point is combined by a sub array antenna 2 and a distribution combining circuit 4. The other feeding point is synthesized by the third sub-array antenna 3 and the distribution / synthesis circuit 5. Considering now the transmission time, the transmission wave input to the terminal 8 is selected by the changeover switch 9 and input to the distribution / synthesis circuit 4 or distribution / synthesis circuit 5. When the distribution / combination circuit 4 is selected, the transmission wave is distributed by the distribution / combination circuit 4, and one of them is connected to the distribution / combination circuit 1c connected to the first sub-array antenna via the changeover switch 13 which is interlocked with the changeover switch 9. It The other side is connected to the distribution / combination circuit 2c connected to the second sub array antenna. Here, the phase shifter 1b of the sub array antenna 1 and the phase shifter of the sub array antenna 2
By setting a predetermined phase by 2b, the sub array antenna 1 and the sub array antenna 2 can be combined and the beam can be scanned in a desired direction. Similarly, when the distribution / combining circuit 5 is selected by the changeover switch 9, the transmission wave is input to the sub-array antenna 1 and the sub-array antenna 3, and the combination makes it possible to perform beam scanning in a desired direction.

Embodiment 2. In the above-described embodiment, the case where the signal is switched by the changeover switch 13 which interlocks with the changeover switch 9 has been described, but it may be changed by a pin diode instead of the changeover switch. In FIG. 2, PIN diodes 14 and 15 are provided in the vicinity of the branch points instead of the changeover switch 13. Here sub array antenna 1
When combining and transmitting the sub array antenna 2 with the sub array antenna 2, the diode 14 is turned on and the diode 15 is turned off, so that the transmission wave branched by the distribution / combining circuit 4 does not leak to the distribution / combining circuit 5. 1 is fed, the sub array antenna 1 and the sub array antenna are combined, and the beam scanning can be performed in a desired direction. When the sub-array antenna 1 and the sub-array antenna 3 are combined and transmitted, by operating the diode 14 in the OFF state and the diode 15 in the ON state, the same operation is performed without the transmission wave leaking to the distribution / combining circuit 4.

[0011]

As described above, according to the present invention, the first sub-array antenna 1 is provided with two feeding points, and one feeding point is combined with the second sub-array antenna 2, and vice versa. Since it is configured to be combined with the third sub-array antenna 3 by the other feeding point, it is possible to easily combine two of the three array antennas and reduce the area of the entire antenna.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a phased array antenna according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a phased array antenna according to another embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional phased array antenna.

[Explanation of symbols]

1 1st sub-array antenna 1a Microstrip patch antenna of 1st sub-array antenna 1b Phase shifter of 1st sub-array antenna 1c Distribution combining circuit of 1st sub-array antenna 2 2nd sub-array antenna 2a 2nd sub-array antenna Microstrip patch antenna 2b Phase shifter for second sub-array antenna 2c Distribution combiner circuit for second sub-array antenna 3 Third sub-array antenna 3a Microstrip patch antenna for third sub-array antenna 3b Phase shift for third sub-array antenna Unit 3c Dividing / synthesizing circuit for third sub-array antenna 4,5 Dividing / synthesizing circuit 8 Input / output terminals 9,13 Changeover switch 14,15 PIN diode

Claims (2)

[Claims] 1. In at least three sub-arrays in which microstrip patch antennas are arranged, two feeding points are provided in the microstrip patch antenna forming the first subarray antenna, and one feeding point is a phase shifter by a changeover switch. Is a phased array antenna configured to be combined with a second sub-array antenna via, and the other feeding point is combined with a third sub-array antenna via a phase shifter. 2. The phased array antenna is provided with two PIN diodes instead of a switch for switching between two feeding points, so that one feeding point is combined with a second sub-array antenna via a phase shifter, The phased array antenna according to claim 1, wherein the other feeding point is configured to be combined with the third abarray antenna via a phase shifter.