JPH05218725A - Phased array antenna - Google Patents

Abstract

PURPOSE:To send a phase control signal of the phased array antenna through one optical fiber cable comprising cables connected in cascade and to eliminate the need for an optical branch unit. CONSTITUTION:An optical signal is converted into an electric signal by an O-E converter 21 of a 1st antenna module 2a from a beam controller 1. The electric signal is waveform-shaped by a waveform shape circuit 22, one output is converted into an optical signal again at an E-O converter 26 and sent to a 2nd antenna module 2b through an optical fiber cable 3b, Moreover, the other electric signal of the waveform shape circuit 22 controls a phase of a signal radio wave outputted from an element antenna 4a by the operation of an S-P converter 23, a phase shifter driver 24 and a digital phase shifter 25 the same as a conventional antenna.

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 which performs beam scanning by changing the output phase of each of a large number of element antennas, and particularly controls the output phase of a digital phase shifter provided for each element antenna. The present invention relates to a phased array antenna with an improved phase shift control circuit.

[0002]

2. Description of the Related Art In a conventional phased array antenna composed of a large number of element antennas of this type,
When it is necessary to perform beam scanning on the element antennas at high speed, it is necessary to optically transmit the phase shift data for controlling the output phase of the digital phase shifter provided for each element antenna.

A conventional phased array antenna for transmitting phase shift data using this type of optical communication apparatus will be described with reference to the block diagram of FIG. 2. The phased array antenna supplies the phase shift data to each phase shift array antenna. , N (n is a plural number) of element antennas 4a, 4b, ..., 4 (n-1), 4n that change the output phase of the signal radio wave according to the above. The beam controller 1 includes n element antennas 4a to 4n.
Of the optical fiber cable 15 by converting a phase shift control signal including n identification codes for respectively identifying the phase shift data and the phase shift data corresponding to the identification code into a serial optical signal.
To send to. This phase shift control signal is input to the optical branching unit 12.

The OE converter 12 in the optical branching unit 12
1 converts the phase shift control signal into an electric signal, the electric signal is buffer-amplified by the buffer 122, and then branched into the number n of the element antennas, and the branched electric signal is the E-O converter 123a to. Each of them is reconverted into an optical signal by 123n. These optical signals are further transmitted by the optical fiber cables 16a to 16n, and the antenna modules (also referred to as phase shift control circuits) 13 respectively.
a to 13n. Antenna module 13a-
13n are respectively connected to the element antennas 4a to 4n having the same suffix. Antenna module 13
Each of a to 13n finds an identification code corresponding to its own antenna module, that is, the connected antenna from the phase shift control signal after converting the optical signal into an electric signal, and decodes the phase shift data corresponding to this identification code. To do. Then, the built-in digital phase shifter is driven according to the phase shift data, and the element antennas 4a ...
The phase of the signal radio wave output by 4n is controlled. As a result,
The beam direction of this phased array antenna is controlled.

Since all of the antenna modules 4a to 4n have the same function, the module 4a will be described in more detail. The optical signal supplied from the optical fiber cable 16a is phase-shifted by the OE converter 21 into a digital electric signal. It is converted into a control signal. This phase shift control signal is waveform shaped by the waveform shaping circuit 131,
The SP conversion circuit 23 recognizes its own identification code and converts only the phase shift data corresponding to this own identification code from serial data to parallel data. Then, the phase shifter driver 24 receiving this parallel data performs ON-OFF control of each bit of the digital phase shifter 25 with this parallel data corresponding to each bit of the digital phase shifter 25, and the element antenna 4a. Set a predetermined phase amount to. As a result, the signal radio wave output from the element antenna 4a is controlled to have an output phase corresponding to the phase shift amount.

[0006]

In this conventional phased array antenna, since an optical signal is transmitted in parallel to each antenna module, an optical branching unit including an OE converter, an EO converter and a buffer amplifier is provided. Is necessary,
Further, it is necessary to connect one optical fiber cable between the antenna module and the EO converter of the optical branching unit.

For the above reasons, in a phased array antenna consisting of a very large number of element antennas, the optical branching unit having an EO converter corresponding to each antenna module becomes large in size, which limits the mounting of the above antennas. There was a problem of receiving it. In addition, there is a problem that the installation route is restricted because several tens of optical fiber cables to each antenna module are partially overlapped.

[0008]

A phased array antenna according to the present invention includes a plurality of element antennas, a plurality of identification codes for respectively identifying the plurality of element antennas, and phase shift data corresponding to the identification codes. A beam controller that converts a phase control signal into a serial optical signal and sends the serial optical signal, and the phase shifter that is connected to one of the element antennas and corresponds to the connection element antenna based on the optical signal from the beam controller. In a phased array antenna including a phase shift control circuit that creates data and controls an output phase of the connection element antenna according to the phase shift data, each of the phase shift control circuits converts the optical signal into an electrical signal. An O-E converter, a waveform shaping circuit that shapes the waveform of the electrical signal, and the electrical signal after the waveform shaping is converted into the optical signal. Includes a E-O converter for conversion, and a phase shifting data reproducing means for reproducing said phase data from said electric signal after waveform shaping.

[0009]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention.

This phased array antenna has the same beam controller 1 and element antenna 4a as in the prior art shown in FIG.
~ 4n. Further, the antenna modules 2a to 2n according to the present embodiment have some functions added to the antenna modules 13a to 13n according to the related art. That is, the waveform shaping circuit 22 incorporated in the antenna module 2a is the antenna module 13 corresponding to this.
In addition to the function of the waveform shaping circuit 131 built in a, it has a function of outputting an electric signal after waveform shaping to another terminal.
Then, the electric signal output from this terminal is supplied to the antenna module (13a to 13n) according to the related art by the E-O converter 26, and all of the phase shift control signals (identification code and this identification code). Is converted to an optical signal and transmitted.

In the above phased array antenna, the optical signal from the beam controller 1 is supplied to the antenna module 2a via the optical fiber cable 3a,
The optical signal output from the antenna module 2a is supplied to the next antenna module 2b via the optical fiber cable 3b. Hereinafter, the optical signals are connected in cascade via the optical fiber cables 3c, ..., 3 (n-1), 3n, and the antenna modules 2b ,.
(N-1), 2n. That is, the antenna modules 2a to 2n not only control the phase of the signal radio waves output by the element antennas 4a to 4n connected to themselves by the input optical signal, but also move to the next antenna module to be connected. An optical signal including a phase control signal is transmitted.

As described above, in this embodiment, the optical signals from the beam controller 1 are supplied to the n antenna modules in cascade, but the optical signals that have passed through many antenna modules are also the electrical signals in the preceding stage. Is reproduced sufficiently, the waveform distortion can be suppressed to the minimum.

[0013]

As described above, according to the present invention, in the phased array antenna composed of an extremely large number of element antennas, the antenna modules corresponding to the respective element antennas can be connected in cascade via the optical fiber cable. In addition to eliminating the need for the optical branching unit in, the antenna modules can be connected with a single optical fiber cable, so there is no restriction on the mounting of other components in the phased array antenna, and the installation route of the optical fiber cable can be improved. It has the effect that it can be freely selected.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional phased array antenna.

[Explanation of symbols]

1 Beam controller 2a-2n, 13a-13n Antenna module 3a-3 (n + 1), 15, 16a-16n Optical fiber cable 4a-4n Element antenna 12 Optical branching unit 21,121 OE converter 22,131 Waveform shaping circuit 23 SP Converter 24 Phase Shifter Driver 25 Digital Phase Shifter 26, 123a to 123n E-O Converter 122 Buffer

Claims (1)

[Claims] 1. A phase shift control signal including a plurality of element antennas, a plurality of identification codes for respectively identifying the plurality of element antennas, and phase shift data corresponding to the identification codes is converted into a serial optical signal. A beam controller for transmission and one of the element antennas, which is connected to one of the element antennas, creates the phase shift data corresponding to the connection element antenna based on the optical signal from the beam controller, and connects the phase shift data according to the phase shift data. In a phased array antenna including a phase shift control circuit that controls an output phase of an element antenna, each of the phase shift control circuits includes an OE converter that converts the optical signal into an electric signal, and a waveform of the electric signal. From the waveform shaping circuit for shaping, the EO converter for re-converting the electrical signal after waveform shaping into the optical signal, and the electrical signal after waveform shaping A phase shift control circuit comprising: a phase shift data reproducing means for reproducing the phase shift data.