METHOD FOR DECIDING ARRAY SPACING OF ARRAY ANTENNA BY USING GENETIC ALGORITHM AND ARRAY ANTENNA HAVING SOFA STRUCTURE WITH IRREGULAR ARRAY SPACING

• US 20090012768A1
• Filed: 12/30/2004
• Published: 01/08/2009
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Son, Seong-Ho, Park, Ung-Hee, Jeon, Soon-Ik, Kim, Chang-Joo
• Granted Patent: US 7,502,764 B2
• Time in Patent Office: Days
• US Class Current: 703/13
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence

Abstract

A method for determining an array space of an array antenna by using a genetic algorithm and an array antenna having a soft structure with irregular array spacing are disclosed. The array antenna having a sofa structure with irregular array spacing, includes: a plurality of radiation elements having an inclined angle based on a horizontal plane and arranged with irregular array spacing for radiating and receiving an radio wave; a plurality of phase shifters for amplifying radiation signals radiated from the plurality of radiation elements and receiving signals received from the plurality of radiation elements, and controlling phases of the radiation signals and the receiving signals; and a radio wave signal coupler for dividing a transmitting signal to the radiation signals, transferring the divided radiation signals to the plurality of phase shifters and coupling the receiving signals from the plurality of phase shifters.

Claims

1. An array antenna having a sofa structure with irregular array spacing, comprising:

a plurality of radiation means having an inclined angle based on a horizontal plane and arranged with irregular array spacing for radiating and receiving an radio wave;

a plurality of phase shifting means for amplifying radiation signals radiated from the plurality of radiation means and receiving signals received from the plurality of radiation means, and controlling phases of the radiation signals and the receiving signals; and

radio wave signal coupling means for dividing a transmitting signal to the radiation signals, transferring the divided radiation signals to the plurality of phase shifting means and coupling the receiving signals from the plurality of phase shifting means, wherein the radiation means are connected to the radio wave signal coupling means through a plurality of coaxial cables, and each of the coaxial cables having a predetermined length determined based on an array space between a m^th radiation means and a (m+1)^th radiation means, the inclined angle of the radiation means and a dielectric constant of the coaxial cable, where m is an integer equal to or larger than 1, wherein the predetermined length of each of the coaxial cables is decided by an equation

$\underset{\_}{L_i+H_i=L_0}$ $\underset{\_}{L_i+H_i=L_0+\left(\underset{m=1}{\overset{i-1}{\sum <br><br>}}<br><br>d_m·<br><br>\sin <br><br><br><br>\mathrm{\alpha <br><br>}\right)/\sqrt{{\mathrm{\varepsilon <br><br>}}_r},\left(2\le <br><br>i\le <br><br>n\right)}$

where L_i+H_i is a length of the coaxial cable between an i^th radiation means to the radio wave coupling means, L₀ is a minimum length, d_m is an array space between a m^th radiation means and a (m+1)^th radiation means, a_m is an inclined angle and ∈

_r is a dielectric constant of the coaxial cable.

2. (canceled)

3. The array antenna having a sofa structure with irregular array spacing as recited in claim 2, wherein the array space between the radiation means is determined by a genetic algorithm.

4. The array antenna having a sofa structure with irregular array spacing as recited in claim 3, wherein the genetic algorithm:

generates a random chromosome population for chromosomes describing location information representing array spaces between the radiation means;

calculates an antenna beam pattern for each chromosome in the generated random chromosome population;

analyzes a sidelobe fitness according to the calculation result of the beam pattern; and

determines whether there is a chromosome having the analyzed fitness satisfying a predetermined reference value, decides the array space as a value of the chromosome satisfying the predetermined reference value when there is the chromosome satisfying the predetermined reference value, and generates new random chromosome population by using a selection step, a crossover step and a mutation step when there is not a chromosome having the analyzed fitness satisfying the predetermined reference value, and repeatedly performs the generation step, the calculation step, the analyzing step and the determining step.

5. The array antenna having a sofa structure with irregular array spacing as recited in claim 4, wherein the chromosome is described as a sequence of binary numbers 0 and 1 representing the location information of the radiation means.

6. A method for determining array spaces of an array antenna by using a genetic algorithm, the method comprising the steps of:

a) generating a random chromosome population for chromosomes describing location information representing array spaces between radiation means, wherein the radiation means are connected to a radio wave signal coupling means through a plurality of coaxial cables, and each of the coaxial cables having a predetermined length determined based on an array space between a m^th radiation means and a (m+1)^th radiation means, an inclined angle of the radiation means and a dielectric constant of the coaxial cable, where m is an integer equal to or larger than 1, the predetermined length of each of the coaxial cables is decided by an equation

$\underset{\_}{L_i+H_i=L_0}$ $\underset{\_}{L_i+H_i=L_0+\left(\underset{m=1}{\overset{i-1}{\sum <br><br>}}<br><br>d_m·<br><br>\sin <br><br><br><br>\mathrm{\alpha <br><br>}\right)/\sqrt{{\mathrm{\varepsilon <br><br>}}_r},\left(2\le <br><br>i\le <br><br>n\right)}$

where L_i+H_i is a length of the coaxial cable between an i^th radiation means to the radio wave coupling means, L₀ is a minimum length, d_m is an array space between a m^th radiation means and a (m+1)^th radiation means, a_m is an inclined angle and ∈

_r is a dielectric constant of the coaxial cable;

b) calculating an antenna beam pattern for each chromosome in the generated random chromosome population;

c) analyzing a sidelobe fitness according to the calculated beam pattern;

d) determining whether there is a chromosome having the analyzed fitness satisfying a predetermined reference value;

e) deciding the array space as a value of the chromosome satisfying the predetermined reference value when there is the chromosome satisfying the predetermined reference value; and

f) generating new random chromosome population by using a selection step, a crossover step and a mutation step when there is not a chromosome having the analyzed fitness satisfying the predetermined reference value, and repeatedly performing the step a) to the step f).

7. The method as recited in claim 6, wherein the chromosome is described as a sequence of binary numbers 0 and 1 representing the location information of the radiation means.

8. The method as recited in claim 7, wherein in the step c), the sidelobe fitness decreases as increasing maximum sidelobe at all area excepting an antenna main beam.

9. The method as recited in claim 8, wherein the array antenna is an array antenna having a sofa structure.