JPH0770903B2 - Antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is an antenna constructed by arranging a plurality of element antennas such as a phased array antenna so that a desired radiation pattern can be obtained in a desired pointing direction. It relates to the device.

[Conventional technology]

Conventionally, in an antenna device configured by arranging a plurality of element antennas uniformly on a straight line or a plane, a phase shifter that changes the phase of the signal and an amplitude or attenuation of the signal are applied to each element antenna. An amplitude controller is connected to control the amplitude level. The phase shifter controls the phase of a signal transmitted or received by each of the element antennas to change the pointing direction of the antenna device, thereby performing beam scanning. The amplitude level of each amplitude controller is set so that the amplitude distribution of each element antenna corresponds to, for example, the Taylor distribution and a predetermined amplitude distribution. It has a side lobe level. However, in addition to those in which the element antennas are arranged on a straight line or a plane as described above, there are increasing demands for those on which the element antennas are arranged on a curved surface. Even in this case, a radiation pattern having a desired sidelobe level is required. Need to get Fig. 6 shows the structure of an antenna device in which element antennas are arrayed on a curved surface as shown in, for example, 1986, National Conference of the Institute of Electronics and Communications, Optical and Radio Division, 82, "Cylinder array antenna for SSR mode S", Tokunaga et al. It is a figure, and (1) in the figure is an element antenna arranged on a cylindrical surface,
(2) is a phase shifter that is connected to each element antenna (1) and is phase-controlled by a phase shifter controller (3), and (4) is also connected to each element antenna (1), and each element antenna is An amplitude controller that controls the amplitude level of the received signal from (1), (5) is a power combiner that combines the signals from these amplitude controllers (4), and (6) is this power combiner (5) It is a receiver that receives a signal from.

In the antenna device having such a configuration, the phase of each phase shifter (2) is changed by the phase shifter controller (3) to perform beam scanning and receive operation. At this time, in order to obtain a desired side lobe level, it is necessary to properly set the amplitude level given to the amplitude controller (4). Conventionally, in order to obtain this amplitude level, each element antenna (1) is arrayed, the angle of the active sector, the value of the edge taper of the amplitude distribution given to each element antenna (1), and the like. Calculate a large number of synthetic radiation patterns according to 1), select the desired side lobe level from the results, determine the parameter conditions at that time, and set the amplitude level of the amplitude controller based on this. I have to.

[Problems to be Solved by the Invention]

Since the conventional antenna device is configured as above, in order to obtain a radiation pattern with a desired sidelobe level in a device having element antennas arranged on a curved surface, many parameters using multiple parameters are used. There was a problem that numerical calculation was necessary.

The present invention has been made to solve the above problems, and an object thereof is to easily obtain an antenna device which can obtain a radiation pattern having a desired sidelobe level.

[Means for Solving the Problems]

The antenna device according to the present invention includes a plurality of element antennas arranged on a curved surface and an amplitude distribution calculation for calculating an amplitude distribution given to each of the element antennas so that a combined radiation pattern by the element antennas is desired. Means and an amplitude controller for controlling the amplitude of the signal transmitted or received by each of the element antennas based on the amplitude distribution calculated by the amplitude distribution calculation means, and the amplitude distribution calculation means is provided for the combined radiation pattern. Calculation means for calculating the amplitude distribution given to each element antenna when the above-mentioned element antennas are projected on a plane intersecting the main beam direction of each element, and each element on the above-mentioned plane with respect to the amplitude distribution calculated by this calculation means Correction means for performing correction based on the antenna density distribution and correction based on the amplitude of each element antenna arranged on the curved surface in the main beam direction; Are those that you configured.

[Action]

In the present invention, the calculation means obtains the amplitude distribution given to each element antenna when each element antenna arranged on the curved surface is projected on the plane intersecting the main beam direction of the synthetic radiation pattern, and the correction means For this amplitude distribution, based on the density distribution of each element antenna projected on the above-mentioned plane, the above-mentioned amplitude distribution is corrected so as to eliminate the influence of the arrangement of the element antennas on that plane on the combined radiation pattern. And, by correcting the amplitude distribution so as to eliminate the influence on the combined radiation pattern due to the inclination of the beam direction radiated from each element antenna arranged on the curved surface, it is given to each element antenna arranged on the curved surface. Amplitude distribution suitable for each element is obtained, and each amplitude controller controls the amplitude of the signal corresponding to each element antenna based on this amplitude distribution. To form a radiation pattern.

Example of Invention

FIG. 1 is a block diagram of an antenna device showing an embodiment of the present invention, and (1) to (6) are the same as the above-mentioned conventional example. (7) is an amplitude distribution calculating means for calculating the amplitude distribution given to each element antenna (1), and (8) is for each amplitude controller (4) based on the amplitude distribution calculated by this amplitude distribution calculating means (7). It is an amplitude setting means for calculating an amplitude level to be given and setting it for each amplitude controller (4).
The amplitude distribution calculation means (7) calculates the amplitude distribution given to each element antenna when each element antenna (1) is projected on a plane, and the calculation means (9). A correction means (10) for correcting the amplitude distribution so as to be suitable for each element antenna (1) arranged on a curved surface.

In the antenna device having such a configuration, the phase shifter controller (3) changes the phase of the phase shifter (2) to perform beam scanning. At this time, in order to obtain a radiation pattern having a desired sidelobe level, it is necessary to set the amplitude level of each amplitude controller (4) to an appropriate value, and this value is calculated by the calculating means (9) and the correcting means ( 10) and the amplitude setting means (8) calculate according to the flow chart shown in FIG. Note that FIG. 3 is an explanatory diagram for explaining the method of this calculation, and shows the element antenna on the YZ plane of FIG. 1, and φ represents the angle from the Z axis. Further, the direction of the scanning beam at a certain point of time is φ = 0 °, and the amplitudes of the respective element antennas E _a1 , E _a2 , ..., E _ai , ... E _aN at this time are E ₁ (θ ₁ ) and E _{2 respectively.} (Θ ₂ ), ..., E _i (θ _i ), ..., E _N (θ
_N ).

First, in step (11), the calculating means (9) makes a plane (hereinafter referred to as a projection plane) at which the positions of the respective element antennas E _a1 , E _a2 , ... E _ai , ... E _aN are orthogonal to the scanning beam direction φ = 0 °. Find the coordinates projected on. Therefore, if the coordinates on the YZ plane of each element antenna are (y ₁ , z ₁ ), (y ₂ , z ₂ ),… (y _i , z _i ),… (y _N , z _N ), it is projected. The coordinates of the element antenna are (y ₁ , 0),
_{(Y 2, 0), ...} (y i, 0), ... the (y _N, 0). Next, the amplitude distribution T ₁ , T ₂ , ... T _i , T for each projected element antenna
_{Find N.} The amplitude distribution that gives the desired radiation pattern by setting for each element antenna when the element antennas are arranged uniformly on a straight line or plane is
For example, it can be obtained by a conventionally known formula such as Taylor distribution. In step (12), this formula is used.
The amplitude distribution T _i is obtained by associating the coordinates on the projection plane of each element antenna. However, the projected element antennas are not in a uniform array. In the case where the element antennas are uniformly arranged on the straight line or the plane, it is desired that the amplitude level of each amplitude controller (4) is set so as to correspond to the amplitude distribution T _i obtained by the above calculation formula. However, in this embodiment, the coordinates of the projected element antennas are nonuniform density distributions that are sparse near the Z axis and dense at both ends, and are uniform on a straight line or a plane. Even if the amplitude level is set in each amplitude controller (4) based on the amplitude distribution T _i obtained by a calculation formula that is appropriate for the array of element antennas in the As a result, the radiated power is weak in the sparse part and strong in the dense part, and the desired radiation pattern cannot be obtained. Therefore, it is necessary to correct this amplitude distribution T _i . In step (13), the correction means (10) first corrects the influence of the density distribution of the element antenna density distribution on the projection plane (hereinafter referred to as weight W _i ). Ask for. The weight W _i is the indicated angle [delta] _i in FIG. _{3, W i = cosδ i (1} ) where [delta] _i is represented by an angle from the z axis to the element antennas E _ai, are subordinate connexion corrected The amplitude distribution T _i ′ is obtained as T _i ′ = T _i · W _i = T _i · cosδ _i (2).

Next, in step (14), the amplitude level A _i set in each amplitude controller (4) is obtained by the amplitude setting means (8).
The amplitude of each element antenna in the main beam direction differs depending on each element antenna. Let this be E _i (δ _i ), then A _i A _i = T _i ′ / E _i (θ _i ) = T _i · W _i / It is represented by E _i (θ _i ) (3).

By giving the amplitude level A _i obtained by such a simple calculation to each amplitude controller (4) connected to each element antenna E _a1 , E _a2 , ... E _ai , ... E _aN , a desired side lobe is obtained. A radiation pattern having a level is obtained.

Fig. 4 shows the radiation pattern obtained when the amplitude level of each amplitude controller (4) is calculated based on the amplitude distribution T _i without correction by the weight W _i and is given to the amplitude controller (4). Is a characteristic diagram showing that the amplitude distribution T _i is a Taylor distribution of −25 dB. As can be seen from FIG. 4, in this case, the side lobe level does not reach the set value of -25 dB.

On the other hand, FIG. 5 is a characteristic diagram showing a radiation pattern obtained by the antenna device of the present invention. A Taylor distribution of −25 dB is set as an amplitude distribution T _i, and an amplitude distribution obtained by performing a correction by weight W _{i is} obtained. The amplitude level of each amplitude controller (4) is set based on T _i ′.

It can be seen from FIG. 5 that a good radiation pattern with a side lobe level of -25 dB can be obtained in the antenna device of the present invention.

In the antenna device configured as in the above embodiment, the desired radiation pattern can be obtained in a short time even though the element antennas are arranged on the curved surface. It is also useful in applications that change.

〔The invention's effect〕

As described above, according to the present invention, a plurality of element antennas arranged on a curved surface, an amplitude distribution calculation means for calculating an amplitude distribution given to each element antenna, and an amplitude distribution calculated by the amplitude distribution calculation means are obtained. An amplitude controller for controlling the amplitude of a signal transmitted or received by each of the element antennas based on the above, and the amplitude distribution calculating means includes each of the element antennas on a plane intersecting the main beam direction of the combined radiation pattern. Calculating means for calculating an amplitude distribution given to each element antenna when projecting a beam, correction for the amplitude distribution calculated by this calculating means based on the density distribution of each element antenna on the plane, and the main beam of each element antenna Since it is composed of a correction means for performing correction based on the amplitude of the direction, it is possible to obtain a combined radiation pattern by the arrangement of each element antenna projected on a plane. Since the influence of the inclination of the beam radiated from each element antenna arranged on the curved surface on the combined radiation pattern is eliminated, the sidelobe level can be lowered and the desired radiation pattern can be obtained. There is an effect.

[Brief description of drawings]

FIG. 1 is a block diagram of an antenna device according to the present invention, FIG. 2 is a flow chart showing a method of calculating an amplitude value of an amplitude controller in the antenna device, and FIG. 3 is an explanatory diagram for explaining this calculation method. FIG. 4 is a characteristic diagram of a radiation pattern without correction, FIG. 5 is a characteristic diagram of a radiation pattern obtained by the antenna device of the present invention, and FIG. 6 is a configuration diagram of a conventional antenna device. In the figure, (1) is an element antenna, (2) is a phase shifter,
(4) is an amplitude controller, (7) is an amplitude distribution calculation means,
(8) is an amplitude setting means. The same reference numerals in each figure indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoji Mano 5-1-1, Ofuna, Kamakura-shi, Kanagawa Mitsubishi Electric Corporation Information Electronics Laboratory (56) Reference JP-A-63-30007 (JP, A)

Claims (1)

[Claims] 1. A plurality of element antennas arranged on a curved surface, and an amplitude distribution calculating means for calculating an amplitude distribution given to each element antenna so that a combined radiation pattern by the element antennas is desired, An amplitude controller that controls the amplitude of a signal transmitted or received by each of the element antennas based on the amplitude distribution calculated by the amplitude distribution calculation means, wherein the amplitude distribution calculation means intersects the main beam of the combined radiation pattern. Based on the density distribution of each element antenna on the plane with respect to the amplitude distribution calculated by this calculation means, the calculation means for calculating the amplitude distribution given to each element antenna when projecting each element antenna on the plane And a correction means for performing correction and correction based on the amplitude of each element antenna arranged on the curved surface in the main beam direction. Na apparatus.