Patent ID: 6903701

Claim:
Method for evaluating electrical field levels |E(r,θ,φ)| in a point P(r,θ,φ) in the near-zone of transmitting antennas, particularly linear array antennas located in the origin of a Cartesian reference system identified by the orthogonal co-ordinates (x, y, z) and the spherical co-ordinates (r,θ,φ), in which: the power (P R ) of the radio-frequency transmitted by the antenna is established; the radiation pattern (D V ) of the antenna in the vertical plane is determined (φ=0); the radiation pattern (D H ) of the antenna in the horizontal plane is determined; the physical height of the antenna is measured; characterised in that said signal power (P R ) and said radiation patterns (D V , D H ) are used as inputs for data processing means to determine the electrical field level according to the following expression: | E ( r ,θ,φ)|=,√{square root over ( P R D H (Ψ))}| E ( r ,θ)| where: D H (Ψ) is the radiation pattern on a conical surface generated by the rotation about axis z in the maximum radiation direction; angle Ψ, function of θ, φ and τ, is given by: ψ ⁡ ( θ , ϕ , τ ) = ϕ ⁢ ⁢ sin ⁢ ⁢ ( β ⁢ ⁢ ( θ , τ ) ) , ⁢ where ⁢ ⁢ β ⁡ ( θ , τ ) = { θ ⁢ ⁢ π π + 2 ⁢ ⁢ τ 0 ≤ θ ≤ π / 2 + τ ( π - θ ) ⁢ ⁢ π π - 2 ⁢ ⁢ τ π / 2 + τ < θ ≤ π τ being the down-tilt of the radiation beam with respect to the horizontal plane (x, y); and E(r,θ) is a vectorial function resulting from: F _ ⁡ ( r , θ ) = j ⁢ ⁢ Z 0 2 ⁢ ⁢ λ ⁢ ∑ n ⁢ exp ⁢ ⁢ ( - j ⁢ ⁢ n ⁢ ⁢ k 0 ⁢ d ) d ⁢ I n ⁢ ⁢ sin ⁢ ⁢ θ d ⁢ θ ^ d where Z 0 is the characteristic impedance of vacuum, λ is the wavelength, k 0 is the propagation constant in vacuum, I n is the nth sample of one-dimension current (ECD) along a thin wire of arbitrary length (L), which generates the same radiative effects of the antenna both in the near-zone and the far-zone, and d and θ d are the spherical co-ordinates of the projection P 1 =(r,θ,0) of said point P(r,θ,φ) in the vertical plane (x, z).