JPH1141023A - Exciting method for array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of mutual coupling among element antennas without providing a hardware means and to obtain a desired radiation characteristics by adjusting an exciting amplitude/phase of the element antennas in the array antenna. SOLUTION: In the case of exciting a plurality of antenna elements of an array antenna, the element antennas 5 are excited so that radiation power of the array antenna is maintained at a specified value in advance in a desired direction and a mutually coupled power with respective element antennas 5 of prescribed element antennas 5 among the element antennas 5 is selected to be a desired power or below that is separately specified from the above desired power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for exciting an array antenna having a plurality of element antennas used for communication, radar, and the like.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a configuration diagram of a conventional array antenna disclosed in Japanese Unexamined Patent Application Publication No. H10-209,004. In FIG. 6, 1a to 1d are dipole antennas as element antennas, 2a to 2d are metal pieces, 3 is coordinates, 4a, 4
b indicates the traveling direction of the radio wave radiated from the dipole antenna 1a. The dipole antennas 1a to 1d are arranged on the xy plane parallel to the y axis, and the metal pieces 2a to 2d are arranged between the dipole antennas perpendicular to the xy plane and parallel to each dipole antenna. . The dipole antennas 1a and 1d are installed on the same x coordinate.

Next, the operation will be described. This array antenna is a phased array antenna that performs beam scanning in the zx plane. Generally, in an array antenna, a radio wave radiated from an element antenna is mutually coupled to another element antenna, and the coupled power causes loss or degrades the active impedance of the element. Therefore, it is desirable to reduce mutual coupling in an array antenna.

In this conventional example, each dipole antenna 1
Metal pieces 2a to 2d are arranged between a to 1d to reduce mutual coupling between elements. For example, radio waves 4 radiated from the dipole antenna 1a in the dipole antennas 1b and 1c directions
Since a is scattered by the metal pieces 2a, 2b, and 2c, the dipole antenna 1a
The mutual coupling to b, 1c is reduced.

Since the radio wave radiated from the dipole antenna 1a in the direction of the metal piece 2c is scattered in the traveling direction 4b, the mutual coupling between the dipole antennas 1a and 1d becomes strong. In this case, since the relative excitation phase difference between the dipole antennas 1a and 1d does not change, the phase of mutual coupling between them does not change. Therefore, this mutual coupling does not cause a change in the active impedance due to the beam scanning.

As described above, in the conventional array antenna, the mutual coupling between the element antennas is reduced by providing hardware means between the element antennas.

[0007]

Since the conventional array antenna is configured as described above, there are the following problems. First, the structure of the array antenna was complicated because hardware means was provided to reduce mutual coupling. Also, in an array antenna used in a wide frequency band or an array antenna in which beam scanning extends to a wide angle, since arrangement intervals of element antennas are narrowed to avoid the appearance of grating lobes, hardware means is arranged between element antennas. It was difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and hardware means is provided by adjusting an excitation amplitude and an excitation phase (excitation amplitude / phase) of an element antenna in an array antenna. It is an object of the present invention to provide a method of exciting an array antenna that can reduce a mutual coupling amount to an element antenna without obtaining a desired radiation characteristic.

[0009]

In view of the above objects, a first aspect of the present invention is to excite an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas. An excitation method for an array antenna, comprising: a mutual coupling power coupling to an individual element antenna of a predetermined element antenna among the element antennas while maintaining a radiation power of the array antenna in a desired direction at a predetermined predetermined value. The element antenna is excited so as to be equal to or less than a desired value defined separately from the desired value.

A second aspect of the present invention is a method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas, the method comprising: Minimize the value of a first evaluation function indicating the difference between the actual radiated power of the array antenna and the radiated power defined in advance as a desired value, and set a predetermined element antenna among the element antennas to an individual element antenna. The element antenna is excited so as to minimize the value of a second evaluation function indicating a difference between the actual mutual coupling power to be coupled and the mutual coupling power predefined as a desired value in each element antenna. Excitation method for array antenna.

A third aspect of the present invention is a method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas, the method comprising: While maintaining the radiated power of the array antenna at a desired value defined in advance, and among the element antennas, the sum of mutual coupling powers coupled to each of the predetermined element antennas is equal to or less than a desired value defined separately from the desired value. The method for exciting an array antenna is characterized in that the element antenna is excited so that

A fourth aspect of the present invention is a method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas, the method comprising: The value of a first evaluation function indicating the difference between the actual radiated power of the array antenna and the radiated power prescribed as a desired value is minimized, and the actual coupling to each of the predetermined element antennas among the element antennas Exciting the element antenna so as to minimize the value of a third evaluation function indicating the difference between the total sum of the mutual coupling powers of the above and the total sum of the mutual coupling powers predetermined as a desired value. In the way.

According to a fifth aspect of the present invention, there is provided an array antenna exciting method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas. Approximately half of the antennas are given a phase obtained by adding a certain amount of phase to the phase forming a desired radiation pattern, and the remaining element antennas are obtained by subtracting a certain amount of phase from the phases forming the desired radiation pattern. Given, and when looking at adjacent surrounding element antennas from each element antenna, the above-mentioned so that the number of element antennas to which the predetermined amount of phase has been added and the number of element antennas to which the predetermined amount of phase has been reduced are substantially the same An array antenna excitation method characterized by exciting an element antenna.

According to a sixth aspect of the present invention, there is provided a method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas, wherein Approximately half of the antennas are given a phase obtained by adding a certain amount of phase to the phase forming a desired radiation pattern, and the remaining element antennas are obtained by subtracting a certain amount of phase from the phases forming the desired radiation pattern. An excitation method for an array antenna, characterized in that the element antennas provided and added with the predetermined phase amount and the element antennas reduced in the predetermined phase amount are excited at random so that the element antennas are arranged.

[0015] A seventh invention of the present invention is the above-mentioned phase-shifting device, wherein the actual mutual coupling power coupled to the individual element antennas is equal to or less than the mutual coupling power predetermined as a desired value in the individual element antennas. The method according to the fifth or sixth aspect of the present invention is characterized in that the amount is determined.

According to an eighth aspect of the present invention, the phase amount is determined such that the total sum of the actual mutual coupling powers coupled to the respective element antennas is equal to or less than the total mutual coupling power predetermined as a desired value. The fifth or sixth aspect of the present invention is an array antenna excitation method according to the fifth aspect.

A ninth aspect of the present invention is a method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas. In the array antenna in which the plurality of element antennas are periodically arranged, the actual mutual coupling power coupled to the individual element antennas is equal to or less than the mutual coupling power predetermined as a desired value in the individual element antennas. An array antenna excitation method is characterized in that the element antenna is not excited in a periodic arrangement.

A tenth aspect of the present invention is a method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas. In the array antenna in which the plurality of element antennas are periodically arranged, a periodic sum is set so that the total sum of the actual mutual coupling powers coupled to the individual element antennas is equal to or less than the total mutual coupling power predetermined as a desired value. An array antenna excitation method is characterized in that the element antenna is not excited in the arrangement.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a configuration diagram of an array antenna to which an array antenna excitation method according to Embodiment 1 of the present invention is applied. In FIG. 1, 5 is an element antenna, 6 is a phase shifter, 7 is an amplitude adjuster such as an amplifier or an attenuator for adjusting the excitation amplitude of the element antenna 5, 8 is a transmitter, and 9 is a signal output from the transmitter 8. Distributor 10 for distribution, excitation amplitude / phase control means for controlling phase shifter 6 and amplitude adjuster 7, excitation amplitude / phase calculation means 11 for calculating excitation amplitude / phase of element antenna 5, and excitation amplitude 12 for excitation A control signal line 13 for sending a control signal from the phase control means 10 to the phase shifter 6 or the amplitude adjuster 13;
Is a coordinate, and 14 is a unit vector representing a direction in which the radiation pattern is evaluated.

First, the operation of the array antenna will be described. The excitation amplitude / phase calculation means 11 calculates the excitation amplitude / phase of each element antenna 5 to achieve a desired radiation pattern and a desired mutual coupling amount between the element antennas, and the excitation amplitude / phase control means 10 calculates the excitation amplitude / phase. The calculation result of the amplitude / phase is transmitted. The excitation amplitude / phase control means 10 controls the amplitude adjuster 7 so as to realize the excitation amplitude / phase as calculated.
And the phase shifter 6. Output from transmitter 8 and distributor 9
The signals distributed by the above-mentioned components excite each element antenna 5 with the excitation amplitude / phase calculated by the excitation amplitude / phase calculation means 11 by the means adjuster 7 and the phase shifter 6.

Next, an excitation method according to the present invention will be described. As described above, an object of the excitation method of the present invention is to reduce the amount of mutual coupling to the element antenna and obtain a desired radiation characteristic by adjusting the excitation amplitude / phase of the element antenna. The excitation amplitude / phase of the element antenna that achieves this purpose is obtained as an excitation amplitude / phase that minimizes an evaluation function F1 shown in Expression (1) described below.

[0022]

(Equation 1)

In the formula (1), m: the identification number of the antenna elements, n: the identification number of predetermined antenna elements to evaluate the mutual coupling power, k: the direction of the identification number for evaluating the radiation pattern, a _m: element excitation amplitude of the antenna #m, phi _m: element antennas #m excitation phase, [rho _m: position vector of the element antennas #m on the coordinate 13, r _k: the unit direction in a direction k evaluating the radiation pattern on the coordinate 13 Vector, G _k : desired radiated power in direction k, P _n : desired value of power mutually coupled to element antenna #n, S _mn : complex S representing mutual coupling between element antennas #m and #n Parameters: M: total number of element antennas, N: total number of predetermined element antennas for evaluating mutual coupling power, K: total number of directions in which radiation patterns are evaluated. When m = n, the S parameter S _mn represents the self-reflection coefficient of the element antenna #m. Also, N ≦ M.

The first term of equation (1) is a term (first evaluation function) for evaluating the difference between the power actually radiated by the array antenna and a desired radiated power in the evaluation direction of the radiation pattern (first evaluation function), and the first term of equation (1). The second term is a term (second evaluation function) for evaluating the difference between the actual power and the desired mutual coupling power that are mutually coupled to a predetermined individual element antenna for which the mutual coupling power is evaluated.

By obtaining the excitation amplitude a _m and the excitation phase φ _m of the element antenna that minimize the evaluation function F1 of the equation (1), it is possible to obtain desired radiation power in the evaluation direction of each radiation pattern, and The power mutually coupled to the predetermined individual element antenna for which the mutual coupling power is evaluated can be set to a desired value. If it is desired to reduce the power mutually coupled to a predetermined individual element antenna, _Pn may be set to a small value.
Further, the predetermined element antenna for evaluating the mutual coupling power may be an all-element antenna.

The excitation amplitude a _m and the excitation phase φ _m of the element antenna which minimize the evaluation function F1 of the equation (1) can be obtained by a non-linear optimization method such as a re-steep descent method. The excitation amplitude / phase calculation means 11 in FIG. 1 according to the first embodiment has a calculation function for obtaining the excitation amplitude a _m and the excitation phase φ _m as described above.

Embodiment 2 FIG. Equation in Embodiment 1
By changing the second term (second evaluation function) of the evaluation function F1 of (1), an evaluation function F2 of the following equation (2) is newly considered.

[0028]

(Equation 2)

In the equation (2), P _all is a desired value of the sum of the power mutually coupled to a predetermined element antenna for evaluating the mutual coupling power. The other variables are the same as in equation (1).

The first term of equation (2) is the same as the first term of equation (1), and is a term for evaluating the difference between the power actually radiated by the array antenna and the desired radiated power in the radiation pattern evaluation direction ( First
The second term of equation (2) is a term for evaluating the difference between the total sum of the actual power coupled to the predetermined element antenna for evaluating the mutual coupling power and the desired total power (the third evaluation function). ).

By obtaining the excitation amplitude a _m and the excitation phase φ _m of the element antenna that minimizes the evaluation function F2 of the equation (2), it is possible to obtain desired radiation power in the evaluation direction of each radiation pattern, and The sum of the power mutually coupled to a predetermined element antenna for which the mutual coupling power is evaluated can be set to a desired value. If you want to reduce the total power of interconnecting a predetermined antenna elements may be set to a small value of P _all. Further, the predetermined element antenna for evaluating the mutual coupling power may be an all-element antenna.

Note that the excitation amplitude a _m and the excitation phase φ _m of the element antenna which minimize the evaluation function F2 of the equation (2) can be obtained by a non-linear optimization method such as the re-steep descent method in the first embodiment. Is the same as The excitation amplitude / phase calculation means 11 in FIG. 1 according to the second embodiment has a calculation function for obtaining the excitation amplitude a _m and the excitation phase φ _m as described above.

Embodiment 3 FIG. 2A is a diagram showing an element antenna array of an array antenna to which the excitation method according to the third embodiment of the present invention is applied. In FIG. 2, 5 is an element antenna, 16 is a predetermined amount of phase given to each element antenna 5, 17 is a coordinate, and 18 is an identification number of each element antenna 5. FIG. 2B shows the element antenna # 7 of FIG. 2A and six element antennas # 1, # 2, # 8, # 12, #
FIG. 11 is a diagram showing a mutual connection relationship between # 11 and # 6.

The array antenna shown in FIG. 2A is a triangular arrangement of 25 element antennas 5 on the xy plane of coordinates 17, and the excitation amplitude of each element antenna 5 is the same, and the excitation phase is initially The same. The electric field of the polarization of each element antenna 5 is y
It is assumed that the array antenna forms a main beam in the z-axis direction with linear polarization parallel to the axis. Element antenna #
S parameters of the mutual coupling _n and # _m is expressed by S _nm.

Next, whether a predetermined phase amount φ is added or subtracted from the excitation phase of each element antenna 5 of the array antenna shown in FIG. 2A is determined. At this time, a predetermined phase amount φ is added to approximately half of all the element antennas 5, and the predetermined phase amount φ is reduced in the remaining element antennas 5. In addition, as for the element antennas 5 adjacent to a certain element antenna 5, the number obtained by adding the predetermined phase amount φ and the number obtained by subtracting the predetermined phase amount φ are approximately half each.

In FIG. 2A, all the element antennas 5 (# 7, # 8, #
9, # 12, # 13, # 14, # 17, # 18, # 1
In 9), the six adjacent element antennas 5 are excited so that three antennas are respectively added and subtracted by a predetermined phase amount φ.

In FIG. 2A, the number of element antennas is two.
Although the number of the antennas is five, such an excitation method may be different from that shown in FIG.

Next, a change in mutual coupling when such an excitation method is performed will be considered. Since it is an adjacent element antenna that strongly couples to a certain element antenna 5, here,
As shown in FIG. 2B, six element antennas 5 (# 1,
# 2, # 8, # 12, # 11, # 6). In FIG. 2B, the S parameter of mutual coupling between the element antenna # 7 and the six surrounding element antennas 5 is a relative value between the element antennas because the excited linearly polarized electric field is parallel to the y-axis. Equation (3) holds from the positional relationship.

S ₇₁ = S ₇₂ = S ₇₁₁ = S ₇₁₂ S ₇₆ = S ₇₈ (3)

Accordingly, the power PM mutually coupled from the six surrounding element antennas 5 to the element antenna # 7 is expressed by the following equation (4).

PM = │2 · S ₇₁ · (e ^jφ + e ^-jφ ) + S ₇₆ · (e ^jφ + e ^-jφ ) │ ² = │ (4 ・ S ₇₁ +2 ・ S ₇₆ ) ・ cos (φ) │ ² ( 4)

The radiated power PR of the array antenna in the z-axis direction is the z power of the radio wave radiated from each element antenna 5.
Assuming that the electric field amplitude in the axial direction is a, it is expressed by equation (5).

[0043] ^{PR = │12 · a · e jφ} +13 · a · e -jφ │ 2 = │24 · a · cos (φ) + a · e -jφ │ 2 (5)

FIG. 3 shows changes in PM and PR when the predetermined phase amount φ obtained from equations (4) and (5) is changed. FIG.
As can be seen from FIG. 7, by bringing the predetermined phase amount φ closer to 90 °, the radiated power PR of the array antenna in the z-axis direction is reduced as shown by the solid line.
, The power PR mutually coupled also decreases as shown by the dashed line. Therefore, in the antenna excitation method of the third embodiment, by selecting an appropriate predetermined phase amount φ, the mutual coupling power of the individual element antennas 5 can be maintained while maintaining the radiated power PR in the z-axis direction at a predetermined value. Can be reduced.

Embodiment 4 FIG. 4 is a diagram showing an element antenna array of an array antenna to which the excitation method according to the fourth embodiment of the present invention is applied. 4 are the same as those in FIG.

The array antenna shown in FIG. 4 is a triangular arrangement of 25 element antennas 5 on the xy plane of coordinates 17, and the excitation amplitudes of the element antennas 5 are the same and the excitation phases are initially the same. The polarization of each element antenna 5 is a linear polarization whose electric field is parallel to the y-axis, and the array antenna forms a main beam in the z-axis direction.

Next, a predetermined phase amount φ is added to or subtracted from the excitation phase of each element antenna 5 of the array antenna of FIG. At this time, approximately half of all element antennas 5 have a predetermined phase amount φ.
In the remaining element antennas 5, the predetermined phase amount φ is reduced. Further, the element antenna 5 to which the predetermined phase amount φ is added and the element antenna 5 to which the predetermined amount of phase φ is subtracted are arranged at random.

As a result, element antennas 5 to which a predetermined amount of phase φ has been added and element antennas 5 to be subtracted have a probability of being substantially the same number around a certain element antenna. Therefore, according to the same principle as in the third embodiment,
By selecting an appropriate predetermined phase amount φ, the mutual coupling power of the individual element antennas 5 can be reduced while maintaining the radiation power PR in the z-axis direction at a predetermined value.

Embodiment 5 In the array antenna, mutual coupling between the element antennas 5 is strong, and excessive power is returned to a device such as an excitation amplifier connected to each of the element antennas 5, which may damage the device. In such a case, the predetermined phase amount φ is determined so that the mutual coupling power of the individual element antennas 5 is equal to or less than the allowable power in the excitation methods described in the third and fourth embodiments. Device damage can be prevented.

Embodiment 6 FIG. In an array antenna in which a device that may be damaged by the reflected power is located between the distributor 9 and the transmitter 8 in FIG. 1, for example, it is necessary to reduce the sum of the mutual coupling power of the element antennas 5. Therefore, in such a case, in the excitation methods described in the third and fourth embodiments, a predetermined phase amount φ
By defining, the device can be prevented from being damaged.

Embodiment 7 FIG. FIGS. 5 (a) and 5 (b) are diagrams showing element antenna arrays of an array antenna to which the excitation method according to the seventh embodiment of the present invention is applied. In FIG. 5, 5a is an excited antenna and 5b is a non-excited element antenna.

In the array antenna shown in FIG. 5, each of the element antennas 5a and 5b is connected to the switch S connected to the element antenna shown by a broken line in FIG.
Excited or non-excited state can be selected by N / OFF.

In an array antenna operating in a very wide frequency band, if the spacing between element antennas is normalized by wavelength, the spacing between element antennas looks large at high frequencies and the spacing between element antennas looks small at low frequencies. Therefore, at low frequencies, generally, mutual coupling between element antennas becomes strong.

Therefore, at a low frequency, FIG.
By periodically excluding the element antenna 5b as shown in (b), the mutual coupling power to the element antenna 5a to be excited can be reduced. In order to reduce the mutual coupling power to the individual element antennas to a desired value or less, the non-excited element antenna 5b is required in a periodic arrangement (regular arrangement).
May be provided.

If the spacing between the element antennas 5a to be excited is increased, the occurrence of grating lobes in the radiation characteristics is a concern. However, since the wavelength is longer at low frequencies, the grating lobes are longer even when the spacing between the element antennas is longer. There is an advantage that it hardly occurs.

Embodiment 8 FIG. In an array antenna in which a device that may be damaged by the reflected power is located between the distributor 9 and the transmitter 8 in FIG. 1, the sum of the mutual coupling powers of the element antennas 5a is equal to or less than a desired value. In this way, the non-excited element antennas 5b are provided as necessary in a periodic arrangement as shown in FIGS. 5 (a) and 5 (b). This can prevent the device from being damaged.

In the first to eighth embodiments, the case where the array antenna is used as the transmitting antenna has been described for convenience. However, even in the case of the receiving antenna, the excitation methods of the first to eighth embodiments are similarly effective. Needless to say.

[0058]

As described above, according to the first aspect of the present invention, in the array antenna excitation method for adjusting the excitation amplitude / phase of the plurality of element antennas to excite the array antenna having the plurality of element antennas, While maintaining the radiated power of the array antenna in a desired direction at a predetermined desired value, and among the element antennas, the mutual coupling power coupled to the individual element antennas in a predetermined element antenna is defined separately from the desired value. By exciting the element antenna so as to be less than the desired value, it is possible to reduce the loss due to mutual coupling and the adverse effect of device damage and obtain desired radiation characteristics without providing hardware means. The effect that it can be obtained is obtained.

According to a second aspect of the present invention, in the array antenna excitation method of adjusting the excitation amplitude / phase of the plurality of element antennas to excite the array antenna having a plurality of element antennas, the array antenna in a desired direction is provided. Minimizing the value of a first evaluation function indicating the difference between the actual radiated power of the antenna and the radiated power predefined as a desired value;
And a value of a second evaluation function indicating a difference between an actual mutual coupling power coupled to each element antenna in a predetermined element antenna and a mutual coupling power predetermined as a desired value in each element antenna among the element antennas. By exciting the element antenna so as to minimize, it is possible to reduce the adverse effects of mutual coupling loss and device damage and obtain desired radiation characteristics without providing hardware means. In addition, the use of the evaluation function has the effect of being more accurate.

According to a third aspect of the present invention, in the array antenna excitation method for adjusting an excitation amplitude / phase of the plurality of element antennas to excite the array antenna having a plurality of element antennas, the array antenna is provided in a desired direction. While keeping the radiated power of the antenna at a predetermined desired value,
In addition, the device antenna is excited so that the sum of mutual coupling powers coupled to each of the predetermined element antennas is equal to or less than a desired value defined separately from the desired value. Without providing the means described above, the effects of reducing the loss due to mutual coupling and the adverse effect of device damage and obtaining desired radiation characteristics can be obtained.

According to a fourth aspect of the present invention, in the array antenna excitation method for adjusting the excitation amplitude / phase of the plurality of element antennas to excite the array antenna having a plurality of element antennas, the array antenna in a desired direction is provided. Minimizing the value of a first evaluation function indicating the difference between the actual radiated power of the antenna and the radiated power predefined as a desired value;
And, among the above-mentioned element antennas, the value of the third evaluation function indicating the difference between the total sum of the actual mutual coupling powers coupled to each of the predetermined element antennas and the total sum of the mutual coupling powers predetermined as a desired value is minimized. By exciting the element antenna as described above, it is possible to reduce the loss due to mutual coupling and the adverse effect of device damage without providing hardware means, and obtain a desired radiation characteristic. The effect of being more accurate is obtained by using.

According to a fifth aspect of the present invention, in the array antenna excitation method of adjusting the excitation amplitude / phase of the plurality of element antennas to excite the array antenna having a plurality of element antennas, A phase obtained by adding a certain amount of phase to a phase forming a desired radiation pattern in approximately half of the elements, and a phase obtained by subtracting a certain amount of phase from the phase forming a desired radiation pattern to the remaining element antennas, And, when looking at the adjacent surrounding element antennas from each element antenna, the element antennas so that the number of the element antennas to which the predetermined amount of phase is added and the number of the element antennas to which the predetermined amount of phase are reduced are substantially the same. To reduce loss due to mutual coupling and the adverse effects of device damage without providing hardware means. It is possible to obtain a desired radiation characteristic,
Further, an effect that this can be performed relatively easily can be obtained.

According to a sixth aspect of the present invention, in the array antenna excitation method for adjusting the excitation amplitude / phase of the plurality of element antennas to excite the array antenna having a plurality of element antennas, A phase obtained by adding a certain amount of phase to a phase forming a desired radiation pattern in approximately half of the elements, and a phase obtained by subtracting a certain amount of phase from the phase forming a desired radiation pattern to the remaining element antennas, And by exciting the element antenna so that the element antenna to which the predetermined phase amount is added and the element antenna with the predetermined phase amount reduced at random, without providing hardware means, The loss due to mutual coupling and the adverse effect of device damage can be reduced, and desired radiation characteristics can be obtained, and this can be performed more easily. Say the effect can be obtained.

In the seventh aspect of the present invention, the fifth and sixth aspects
In the invention, the amount of phase is determined so that the actual mutual coupling power coupled to the individual element antennas is equal to or less than the mutual coupling power predetermined as a desired value in the individual element antennas. The effect of reducing the loss due to mutual coupling and the harmful effects of damage to devices particularly connected to individual element antennas among devices can be obtained without providing any means of wear.

In the eighth aspect of the present invention, the fifth and sixth aspects are
In the invention, the phase amount is determined so that the total sum of the actual mutual coupling powers coupled to the respective element antennas is equal to or less than the total mutual coupling power defined in advance as a desired value. Without providing
The effect of reducing the loss due to mutual coupling and the harmful effects of breakage of the device, particularly the device commonly connected to each element antenna among the devices, can be obtained.

According to a ninth aspect of the present invention, in the array antenna excitation method of adjusting the excitation amplitude / phase of the plurality of element antennas to excite the array antenna having the plurality of element antennas, In the array antenna in which the element antennas are periodically arranged, the periodic mutual coupling power coupled to the individual element antennas is set to be less than or equal to the mutual coupling power predetermined as a desired value in the individual element antennas. Since the element antenna is de-energized in a simple arrangement, it is possible to reduce the loss due to mutual coupling and the adverse effect of device damage without providing hardware means, and it is possible to obtain the effect that this can be performed more easily. .

According to a tenth aspect of the present invention, in the array antenna excitation method of adjusting the excitation amplitude / phase of the plurality of element antennas and exciting the array antenna having the plurality of element antennas, In the array antenna in which the element antennas are periodically arranged, the antenna elements are periodically arranged so that the sum of the actual mutual coupling powers coupled to the individual element antennas is equal to or less than the total mutual coupling power predetermined as a desired value. Since the above-mentioned element antenna is de-energized, the effect of reducing the loss due to mutual coupling and the damage of the device, particularly the device commonly connected to each element antenna, can be reduced without providing hardware means. can get.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an array antenna to which an excitation method according to Embodiments 1 and 2 of the present invention is applied.

FIG. 2 is a diagram showing an element antenna arrangement of an array antenna to which an excitation method according to Embodiments 3, 5, and 6 of the present invention is applied.

FIG. 3 is a diagram illustrating a change in radiated power PR of the array antenna in the z-axis direction and a power PM mutually coupled from six peripheral element antennas when a predetermined phase amount φ is changed.

FIG. 4 is a diagram showing an element antenna array of an array antenna to which an excitation method according to Embodiments 4, 5, and 6 of the present invention is applied.

FIG. 5 is a diagram showing an element antenna array of an array antenna to which the excitation method according to the seventh and eighth embodiments of the present invention is applied.

FIG. 6 is a configuration diagram of a conventional array antenna.

[Explanation of symbols]

5, 5a, 5b element antenna, 6 phase shifter, 7 amplitude adjuster, 8 transmitter, 9 distributor, 10 excitation amplitude / phase control means, 11 excitation amplitude / phase calculation means, 12 control signal line.

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Hideki Fushimi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (10)

[Claims] 1. A method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas, the method comprising:
In the desired direction, the radiation power of the array antenna is maintained at a predetermined desired value, and the mutual coupling power coupled to each element antenna in a predetermined element antenna among the element antennas is separately defined from the desired value. An excitation method for an array antenna, wherein the element antenna is excited so as to have a desired value or less. 2. A method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas,
A first indicating the difference between the actual radiated power of the array antenna in a desired direction and the radiated power predetermined as a desired value;
Of the evaluation function, and the difference between the actual mutual coupling power coupled to each element antenna in a predetermined element antenna and the mutual coupling power defined in advance as a desired value in each element antenna. A method of exciting an array antenna, comprising exciting the element antenna so as to minimize the value of a second evaluation function indicating 3. A method for exciting an array antenna having a plurality of element antennas, the method comprising adjusting an excitation amplitude / phase of the plurality of element antennas and exciting the array antenna.
It is desirable to keep the radiated power of the array antenna in a desired direction at a predetermined desired value, and to define the sum of mutual coupling powers coupled to each of the predetermined element antennas separately from the desired value. A method for exciting an array antenna, comprising exciting the element antenna so that the value is equal to or less than a value. 4. A method for exciting an array antenna having a plurality of element antennas by adjusting an excitation amplitude / phase of the plurality of element antennas, the method comprising:
A first indicating the difference between the actual radiated power of the array antenna in a desired direction and the radiated power predetermined as a desired value;
And the difference between the sum of the actual mutual coupling power that is coupled to each of the predetermined element antennas and the sum of the mutual coupling power defined in advance as a desired value is minimized. 3. An excitation method for an array antenna, wherein the element antenna is excited so as to minimize the value of the evaluation function of (3). 5. An array antenna excitation method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas,
A phase obtained by adding a fixed amount of phase to a phase forming a desired radiation pattern is given to almost half of all the element antennas,
The remaining element antennas are given a phase obtained by subtracting a predetermined phase amount from a phase forming a desired radiation pattern, and when looking at adjacent element antennas from each element antenna, the predetermined phase amount is added. And exciting the element antennas so that the number of the element antennas and the number of the element antennas having the predetermined amount of phase reduced are substantially the same. 6. A method for exciting an array antenna having a plurality of element antennas, wherein said array antenna is excited by adjusting the excitation amplitude / phase of said plurality of element antennas.
A phase obtained by adding a fixed amount of phase to a phase forming a desired radiation pattern is given to almost half of all the element antennas,
The remaining element antennas are given a phase obtained by subtracting a predetermined amount of phase from the phase forming a desired radiation pattern, and the element antenna obtained by adding the predetermined phase amount and the element antenna obtained by reducing the predetermined phase amount are random. A method for exciting an array antenna, wherein the element antenna is excited so as to be arranged in the array antenna. 7. The phase amount is determined such that actual mutual coupling power coupled to each of the element antennas is equal to or less than a predetermined mutual coupling power as a desired value in each of the element antennas. 7. The method for exciting an array antenna according to claim 5, wherein 8. The phase amount is determined such that the total sum of the actual mutual coupling powers coupled to the respective element antennas is equal to or less than the total mutual coupling power predetermined as a desired value. Item 7. The method for exciting an array antenna according to item 5 or 6. 9. A method for exciting an array antenna having a plurality of element antennas, the method comprising adjusting an excitation amplitude / phase of the plurality of element antennas and exciting the array antenna.
In an array antenna in which the plurality of element antennas are periodically arranged on a plane, the actual mutual coupling power coupled to the individual element antennas is equal to or less than the mutual coupling power predetermined as a desired value in the individual element antennas. A method for exciting an array antenna, wherein the element antennas are not excited in a periodic arrangement. 10. A method for exciting an array antenna having a plurality of element antennas by adjusting the excitation amplitude / phase of the plurality of element antennas, wherein the plurality of element antennas are arranged on a plane. In the arranged array antenna, the element antennas are periodically arranged so that the sum of the actual mutual coupling powers coupled to the individual element antennas is equal to or less than the total mutual coupling power defined as a desired value. An excitation method for an array antenna, wherein the excitation is performed.