Satellite-Borne VLF Array Radiation Calculation Under Ionospheric Coupling
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Solution Overview
Problem
The calculation of the radiation field and array factor of satellite-borne array antennas is inadequate, particularly considering mutual coupling and ionospheric anisotropy, lacking effective methods to account for these factors in satellite-borne VLF array antennas.
Innovation Solution
A method involving the calculation of a kernel function for satellite-borne array antennas in an ionosphere environment, solving current integral equations to determine current distribution, and combining these with a three-dimensional Fourier transform to derive the radiation field, further simplified by an array factor analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional single antenna is used, then the structure is simple, but the radiation efficiency is insufficient
Solution Approach 1:
The patent combines multiple space antennas into a satellite-borne antenna array system. By merging multiple antenna elements (including vertical and inclined antennas) into a coordinated array, the system achieves improved current moment and radiation efficiency while maintaining manageable structural complexity through systematic design
2Reliability
If multiple space antennas are used to form an array, then the radiation efficiency is improved, but the calculation complexity increases due to mutual coupling effects
Solution Approach 1:
The patent segments the complex array calculation problem into distinct components: individual antenna current distributions are calculated separately using integral equations, then mutual coupling effects are incorporated systematically. The radiation field calculation is divided into near-field and far-field components, with the array factor method separating element patterns from spatial arrangement effects
Solution Approach 2:
The patent introduces the array factor as an intermediary mathematical tool that bridges individual antenna characteristics and overall array radiation patterns. The array factor accounts for mutual coupling and spatial relationships without requiring direct solution of the entire coupled system, thereby reducing calculation complexity while maintaining accuracy
3Measurement precision
If ionospheric anisotropy is considered in the calculation, then the precision is improved, but the calculation time increases
Solution Approach 1:
The patent incorporates ionospheric anisotropy by using direction-dependent propagation parameters in the kernel function. The refractive index and wave propagation characteristics are adjusted based on the magnetic field direction and frequency, allowing accurate representation of ionospheric effects without requiring full-wave numerical simulations that would be computationally prohibitive
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Provides high-precision calculation of radiation field and array factor, reducing complexity and time while ensuring accuracy, supporting optimal design and efficiency of satellite-borne VLF array antennas.
Implementation Method 1
by calculating a relative transverse propagation distance Δρ and a relative longitudinal propagation distance Δz between the observation point and the electric dipole, and performing a three-dimensional Fourier transform on a Maxwell's equation, the radiation field generated by the electric dipole at any position can be obtained
Implementation Method 2
Establishing and solving N current integral equations satisfied by the array antennas in the ionosphere environment by using the kernel function obtained in step (1) according to a boundary condition, thereby obtaining a current distribution of each antenna in an array
Data Source
AI summary
Disclosed is a method and a device for calculating a radiation field of satellite-borne array antennas. comprising: calculation of a kernel function of an antenna: calculating the kernel function of a very-low-frequency antenna in an ionospheric environment; calculation of an antenna current distribution: establishing and solving N current integral equations satisfied by the array antennas to obtain the current distribution of each antenna in the array; calculation of the radiation fields of the array antennas: calculating and summing the radiation fields of all antenna elements to obtain the radiation field of the array antennas; calculation of an array factor: analyzing a propagation phase difference between the ith antenna and the first antenna, and calculating the array factor of the array antennas accordingly, further simplifying the radiation field of the array antennas. The present disclosure has advantages of less calculation time consumption and high accuracy.