JPS5915203B2 - electronic scanning antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to suppress antenna pattern deterioration due to quantization phase error caused by a quantization phase shifter in beam scanning of an equidistant electronic scanning antenna.

In the conventional antenna of this kind, as shown in Fig. 1, the phase shift amount is 1, whereas the phase shift amount that can be set by the quantization phase shifter is step-like, as shown by reference numeral 2 in the figure. Therefore, a quantization phase error of 3 occurs, which has the disadvantage of deteriorating the antenna pattern.

Furthermore, if wide-angle scanning is performed by frequency scanning, there is a drawback that a wide frequency band is required of the transmitter/receiver.

In order to solve these drawbacks, the present invention is characterized in that it eliminates the quantization phase error of each antenna element and enables minute angle scanning by frequency scanning.

FIG. 2 is a block diagram showing an embodiment of the present invention, in which 4 and 5 are the first antenna element and the first quantization phase shifter, respectively, and 6 and 7 are the second antenna, respectively. element and the second quantization phase shifter, 8 and 9 are respectively nth
a th antenna element and an n th quantization phase shifter, 10,
11 are the Nth antenna element and the Nth quantization phase shifter, respectively.

FIG. 3 is a diagram showing the amount of phase shift applied to the first quantization phase shifter 5 to the Nth quantization phase shifter 11 according to the present invention.

Note that the number of bits of the quantization phase shifter can be set arbitrarily, but
For convenience of explanation, 4 bits are used.

At this time, the /JX variable phase shift amount is 3600
3600×±, that is, 225°4, and as shown by the solid line 13 in FIG. If the beam is applied by a quantization phase shifter, the beam will be scanned in a constant direction, and the antenna pattern will not be degraded due to quantization phase error.

Similarly, the solid line 14 in FIG. 3 shows the situation when the phase of the n-th antenna element 8 is set to 2n times 22.5°.

In general, the phase of the j-th antenna element 8 is changed by the n-th quantization phase shifter to the maximum of the quantization phase shifter. If mn times (where m is an integer) the beam is -2A (degrees), the beam will be scanned discretely, but there will still be no quantization phase error and the antenna pattern will not deteriorate due to it. do not have.

Note that since the beams are discretely scanned by the quantization phase shifter, if power is supplied to each quantization phase shifter by the frequency scanning antenna feed line 12 as shown in FIG. The beam can be scanned with reduced granularity without any quantization phase shift error.

As described above, since the electronic scanning antenna according to the present invention has no quantization phase error, there is an advantage that deterioration of the antenna pattern due to the quantization phase error can be suppressed.

[Brief explanation of the drawing]

Figure 1 shows a conventional electronic scanning antenna (number of antenna elements = N
Fig. 2 shows the quantization phase error of each antenna element.
This figure is a diagram showing the configuration of an antenna according to the present invention, and FIG. 3 is a diagram showing the phase of each antenna element according to the present invention. In the figure, 1 is the ideal phase shift amount, 2 is the phase shift amount that can be set by the quantization phase shifter, 3 is the quantization phase error, 4, 6, 8
．． 10 are the 1st, 2nd, nth, and Nth, respectively.
The antenna elements 5°γ, 9 and 11 are the first antenna elements, respectively.
th, second, nth, Nth quantization phase shifter;
12 is a frequency scanning antenna feed line, 13 is a settable phase shift amount of each antenna element without quantization phase error when the phase difference between each antenna element is 22.5°, and 14 is a settable phase shift amount between each antenna element. This is the amount of phase shift that can be set for each antenna element without a quantization phase error when the phase difference is set to 45 degrees.

Claims (1)

[Claims] 1. In a uniformly spaced electronic scanning antenna with a quantization phase shifter, the beam scanning angle is set in a direction in which no quantization phase error occurs, and by combining this with frequency scanning, beam scanning without quantization phase error is achieved. An electronic scanning antenna characterized by what it has done.