Reconstruction of Equivalent currents Using the Scalar Surface Integral Representation

Författare

Kristin Persson
Mats Gustafsson

Summary, in English

Knowledge of the current distribution on a radome can be used to improve

radome design, detect manufacturing errors, and to verify numerical simulations.

In this paper, the transformation from near-field data to its equivalent

current distribution on a surface of arbitrary material, i.e., the radome, is

analyzed. The transformation is based on the scalar surface integral representation

that relates the equivalent currents to the near-field data. The presence

of axial symmetry enables usage of the fast Fourier transform (FFT) to reduce

the computational complexity. Furthermore, the problem is regularized using

the singular value decomposition (SVD). Both synthetic and measured data

are used to verify the method. The quantity of data is large since the height

of the radome corresponds to 29 − 43wavelengths in the frequency interval

8.0 − 12.0GHz. It is shown that the method gives an accurate description

of the field radiated from an antenna, on a surface enclosing it. Moreover,

disturbances introduced by copper plates attached to the radome surface, not

localized in the measured near field, are focused and detectable in the equivalent

currents. The method also enables us to determine the phase shift of the

field due to the passage of the radome, cf. the insertion phase delay.

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