JPH02151105A - Antenna system - Google Patents

Abstract

PURPOSE:To improve the S/N of the communication by adopting the constitution such that a phase quantity correcting a phase fluctuation attended with the changeover of a plane in addition to the setting phase for beam scanning so as to correct the phase change attended with the changeover of a plane of a phased array. CONSTITUTION:The phase change quantity phi attended with the changeover of a phased array antenna is operated. Moreover, let a relative phase quantity of each phase shifter required for the beam scanning be thetan, a correction phase arithmetic unit 7 applies operation of phin=phin-phi for a number of times of the number of phase shifters in one phased array, where phin is a set phase quantity of each phase shifter. A phase shifter drive circuit 4 sets each phase shifter based on the result of operation of the correction phase arithmetic unit 7. In the case of the changeover of the phased array, since the phase shifter drive circuit 4 drives the phase shifter based on the result of operation of the correction phase calculator 7, the phase change attended with the changeover of the plane of the antenna is decreased and the S/N of the communication is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a phased array antenna used in communications that modulates the phase of a signal.

[Conventional technology]

Figure 3 shows, for example, an electronics conference recorder (Electro, Conf, Rec, +
1984+ pp4.1.1 to 4.1.3), and FIG.
) is a top view, and Figure 3 (bl is a front view. A, B in the figure)
, C, D, and E are phased array antennas. Fourth
The figure shows the configuration of a phased array antenna.
In the figure, 1 is an element antenna, 2 is a phase shifter, 3 is a combiner, and 4 is a phase shifter drive circuit that drives the phase shifter 2. Figure 5 shows the phased array antennas A, B, C,
This is a diagram showing the connection state of D and E. In the diagram, 5 is a switch and 6 is a receiver.

Next, the operation will be explained.

In one phased array antenna, the phase shifter 2 shown in FIG. 4 is driven by a phase shifter drive circuit 4 to change the phase of the radio signal received by the element antenna 1 and scan the beam. If high gain is required over the half-space, the third
As shown in the figure, phased arrays A, B, C, D, E
are arranged in a polygonal manner, and the beam scanning range of each phased array is set at an aperture angle θ shown in FIG. be within the cone of The beam scanning range of a one-plane phased array is θ. If the number exceeds 1, the switch 5 in FIG. 5 is switched, and beam scanning is performed using another phased array.

[Problem to be solved by the invention]

The conventional antenna device was configured as described above.
Next, consider the case where this antenna device is used for communication. When phase modulation is used as the modulation method, communication information is transmitted by modulating and demodulating the phase of the composite signal. Therefore, when the direction of arrival of the signal changes and beam scanning is performed, it is necessary to keep the gain high and to keep the phase of the composite signal constant. For example, in a spread spectrum system that performs phase modulation, the signal-to-noise ratio of communication generally deteriorates when the phase change is 10'' or more, and the modulation locks off when the phase change is 30'' or more. FIG. 6 shows a phase change when a digital phase shifter is used in an 80-element phased array.

From Figure 6, when using a 3-bit phase shifter, if the setting error is 17.5° (r, m, s) or more, the phase change is 1
It becomes 0° or more.

In a normal phase shifter, the setting error is 10' (r, m, s)
Therefore, in beam scanning of a single-plane phased array, the phase change is considered to be small. However, as shown in FIG. 5, when a plurality of phased arrays are switched and used, a phase change occurs depending on the distance between the phase centers of the arrays. Generally, the distance between these phase centers is larger than the wavelength, and therefore the phase change is also large enough to not be ignored. Therefore, there was a problem that the signal-to-noise ratio was poor.

This invention was made to solve the above-mentioned problems, and its purpose is to provide an antenna device that can reduce the phase change caused by switching the plane of a phased array antenna and improve the signal-to-noise ratio of communication. do.

[Means to solve the problem]

The antenna device according to the present invention calculates the amount of phase change φ of the composite electric field due to switching of the phased array antenna, and furthermore, when the relative phase amount of each of the phase shifters necessary for beam scanning is θn, Set phase amount θn-φ of phase gear
The phase shifter is driven based on the result of the calculation.

[Effect]

In this invention, in addition to the set phase for beam scanning, each phase shifter is given a phase amount to correct phase fluctuations caused by surface switching, and is configured to correct phase changes caused by surface switching of the phased array. It is possible to reduce the phase change caused by switching the plane of the array antenna, and improve the signal-to-noise ratio of communication.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an antenna device according to an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 5 indicate the same or corresponding parts, and 7 is a correction phase calculation device.

Next, the operation will be explained.

Assume that phased array A is used in the initial state. When the beam scanning direction changes and enters a beam scanning area where phased array B is used, switch 5 shown in FIG. 1 is switched to connect phased array B and receiver 5. Here, the unit vector in the beam scanning direction for switching from phased array A to phased array B is dl, the position vector of the phase center of phased array A is 1rA, and the position hector of the phase center of phased array B is 1r□. The phase change φ when switching from phased array A to phased array B is expressed by the following equation.

Here, if the set phase amount of the phase shifter connected to the n-th element antenna for beam scanning is θn, the correction phase calculation device 7 sets the set phase amount φn of the phase shifter as follows:
The following calculation is performed for the number of phase shifters in one phased array.

φn-θn-φ (2) The phase shifter drive circuit 4 sets each phase shifter based on the calculation result of the correction phase calculation device 7. FIG. 2 is a flowchart showing the above control operation.

In this way, in this embodiment, the amount of phase change φ of the composite electric field due to switching of the phased array is calculated, and the set phase amount ψn of the phase shifter is determined from this amount of change φ and the set phase amount θn for beam scanning. Since the correction phase calculation device 7 is provided and the phase shifter drive circuit 4 drives the phase shifter based on the calculation result of the correction phase calculation device 7 when switching the phased array, it is possible to switch the plane of the phased array antenna. The phase change associated with this can be reduced, and the signal-to-noise ratio of communication can be improved.

〔Effect of the invention〕

As described above, according to the present invention, when calculating the amount of phase change φ of the composite electric field due to switching of the phased array antenna, and further assuming that the relative phase amount of each of the above-mentioned phase shifters necessary for beam scanning is θn, Setting phase amount θn− of each phase shifter above
By calculating φ and driving the phase shifter based on the calculation result, it is possible to reduce the phase change caused by switching the plane of the phased array antenna, improve the signal-to-noise ratio of communication, and improve accuracy. This has the effect of enabling good communication.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an antenna device according to an embodiment of the present invention, FIG. 2 is a flow chart diagram showing the control operation of the present invention, FIG. 3 is a diagram showing the configuration of a conventional antenna device, and FIG. 4 5 is a diagram showing the configuration of the phased array antenna, and FIG. 5 is a diagram showing the connection state of the phased array antenna.
FIG. 6 is a diagram showing the relationship between the setting error of the phase shifter and the amount of phase fluctuation. 1 is an element antenna, 2 is a phase shifter, 3 is a combiner, 4 is a phase shifter drive circuit, 5 is a switch, 6 is a receiver, 7 is a correction phase calculation device, A, B, C, D, E are It is a phased array antenna. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A plurality of phased array antennas each having a plurality of element antennas, a phase shifter connected to each of the element antennas, and a synthesizer that combines the outputs of the phase shifters; and switching the phased array antenna. Calculate the amount of phase change φ of the combined electric field due to switching of the switch and the phased array antenna, and further set the relative phase amount of each phase shifter necessary for beam scanning as θ_n, and then calculate the settings of each phase shifter. An antenna device comprising: a corrected phase calculation device that calculates a phase amount θ_n−φ; and a phase shifter drive circuit that drives the phase shifter based on the calculation result of the corrected phase calculation device. .