Omnidirectional array antenna and beamforming method therefor
An omnidirectional array antenna includes N omnidirectional subarray units circumferentially arranged to form a circular array, where each of the omnidirectional subarray units includes p coaxially-arrayed symmetrical oscillators, and N and p are both natural numbers. The omnidirectional array antenna beamforming method includes various omnidirectional subarray units stimulated by equiamplitude, in-phase or out-phase stimulation, thereby forming different types of transaction beams, such as an omnidirectional beam, a double-beam, a triple-beam, and a quadruple-beam.
1. An omnidirectional array antenna, comprising:
N omnidirectional subarray units that are circumferentially arranged to form a circular array, a diameter of the circular array being an integral multiple of a central wavelength λ c , and
each of the omnidirectional subarray units comprising p coaxially-arrayed symmetrical oscillators,
wherein N and p are both natural numbers.
2. The omnidirectional array antenna according to claim 1 , wherein the coaxially-arrayed symmetrical oscillators of the omnidirectional subarray units are half-wave oscillators.
3. The omnidirectional array antenna according to claim 2 , wherein the symmetric oscillators of the omnidirectional subarray units are coaxially arrayed into a vertically polarized subarray or coplanarly arrayed into a horizontally polarized subarray.
4. The omnidirectional array antenna according to claim 1 , wherein the N omnidirectional subarray units are vertically arranged at equal intervals at circumferential azimuth angle φ n =2·n·π/N, wherein n=1, 2, 3, . . . , N.
5. The omnidirectional array antenna according to claim 1 , wherein the symmetric oscillators of the omnidirectional subarray units are printed on a PCB dielectric plate, the dielectric plate being perpendicular to a diameter of the circular array.
6. The omnidirectional array antenna according to claim 1 , wherein the symmetrical oscillators of the omnidirectional subarray units are constructed in a form of a metal tube.
7. The omnidirectional array antenna according to claim 1 , wherein the omnidirectional subarray units have different types of beams, comprising at least one of a single omnidirectional beam, a single directional beam, a directional narrow double-beam, a directional wide double-beam, a non-collinear directional double-beam, a directional unequal-width double-beam, a directional triple-beam, and a directional quadruple-beam.
8. An omnidirectional array antenna beamforming method, applied to the omnidirectional array antenna according to claim 1 , comprising:
forming different types of beams by stimulating various omnidirectional subarray units by equiamplitude, in-phase or out-phase stimulation.
9. The omnidirectional array antenna beamforming method according to claim 8 , wherein the different types of beams comprise at least one of a single omnidirectional beam, a single directional beam, a directional narrow double-beam, a directional wide double-beam, a non-collinear directional double-beam, a directional unequal-width double-beam, a directional triple-beam, and a directional quadruple-beam.
10. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the single omnidirectional beam being stimulating various omnidirectional subarray units by means of equiamplitude, a phase satisfying the following: four odd-numbered array elements being of a same phase, that is, β 1 =β 3 =β 5 =β 7 ; four even-numbered array elements being of a same phase, that is, β 2 =β 4 =β 6 =β 8 ; and the two sets of phases respectively satisfying relations: β 1 =β 2 +Δβ and Δβ∈[ 0 ,π/2].
11. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the single directional beam being stimulating various omnidirectional subarray units by means of equiamplitude, and a phase satisfying the following:
β
n
=
±
2
·
i
·
π
-
k
·
R
·
sin
θ
m
·
cos
(
φ
m
-
2
n
π
N
)
in the relation, i and N are integers, n=1, 2, 3 . . . , N; k=2π/λ is a number of waves in the air, and θ m and φ m are respectively an elevation angle θ m and an azimuth angle φ m pointed by a maximum beam.
12. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the directional narrow double-beam being stimulating various omnidirectional subarray units by means of equiamplitude, a phase satisfying the following:
β 1 =β 4 =(1/1.75+2·q)·π, β 2 =β 3 =2·q·π, β 5 =β 8 =[(1/1.75)+2·q]·π, and β 6 =β 7 =(1+2·q)·π, wherein q is an integer.
13. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the directional wide double-beam being stimulating various array elements by means of equiamplitude, and a phase satisfying the following:
β 1 =β 2 =β 3 =β 4 =2·q·π; β 5 =β 6 =β 7 =β 8 ==(1+2·q)·π, wherein q is an integer.
14. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the directional unequal-width double-beam being stimulating various array elements by means of equiamplitude, the phase satisfying the following:
β 1 =β 3 ={[1−cos(π/4)]+2·q}·π, β 2 =2·q·π, β 4 =β 8 =π,
β 5 =β 7 =[(1−1/4)+2·q]·π, and β 6 =[(1−1/6)+2·q]·π, wherein q is an integer.
15. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the non-collinear directional double-beam being stimulating various array elements by means of equiamplitude, a phase satisfying the following:
β 1 =β 3 =(1/1.75+2·q)·π, β 2 =2·q·π, β 4 =(1/1.75+1/2+2·q)·π,
β 5 =[(1+1/1.75+1/2)+2·q]·π, β 7 =π, and β 6 =β 8 =[(1+1/1.75)+2·q]·π, wherein q is an integer.
16. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the directional triple-beam being stimulating various array elements by means of equiamplitude, a phase satisfying the following:
β 1 =β 3 ={[1−cos(π/4)]+2·q}·π, β 2 =2·q·π, β 4 =β 8 =(1+2·q)·π,
β 5 =[(1+1/3.5)+2·q]·π, β 6 =[(1+1/2.875)+2·q]·π, and
β 7 =[(1−1/3.5)+2·q]·π, wherein q is an integer.
17. The omnidirectional array antenna beamforming method according to claim 9 , wherein the omnidirectional array antenna comprises eight omnidirectional subarray units, a forming algorithm of the directional quadruple-beam being stimulating various array elements, a phase satisfying the following: β 1 =β 4 =β 5 =β 8 =2·q·π and β 2 =β 3 =β 6 =β 7 =(1+2·q)·π, wherein q is an integer.