Comparison Between Two Phase-Retrieval Methods for Electromagnetic Source Modeling

Abstract

Abstract-Phase-retrieval from measured phaseless field data is of interest for various applications including electromagnetic dosimetry, electromagnetic compatibility investigations, near-field to far-field transformations and antenna diagnostics. In this study two phaseretrieval methods, namely the adjoint field method and the phase angle gradient method, are compared using 3D numerical test cases. The methods were previously presented by us, but the adjoint field method was at that time only implemented in 2D. In this study the adjoint field method has been extended to 3D, which makes it possible to test the method for more realistic test cases and to compare it with the phase angle gradient method. The results show that the phase angle gradient method is able to retrieve the phase with better accuracy than the adjoint field method. Moreover it gives results that agree well with correct phase. The phase angle gradient method was also tested with measured magnetic field. The obtained phase angles on a measurement plane in front of the source gave calculated field amplitudes that agree well with measured field.

Source Reconstruction Method Using Phase-Less Magnetic Near-Field Measurements: Application of the Method of Moment with Roof-Top Basis Functions

“…According to (7) and using the inverse Fourier transform, the following equation can be obtained, which means that 0 ) , + − 1 can be easily calculated using the Fourier transform of H(r). Eq.…”

“…In the third step, by calculating the inverse Fourier transform of the projected planewave spectrum in plane P2, the field in this plane can be estimated. This is done using (7). The estimated field has both amplitude and phase.…”

“…In the seventh step, the projected planewave spectrum in plane P1 is transformed into the space domain using an inverse Fourier transform (7). The calculated magnetic field in plane P1 has both amplitude and phase.…”

“…The phase information can be retrieved using different techniques typically based on iterative schemes in which the phase of the near field at two different parallel planes is reconstructed in a forwardbackward fashion [2]- [6]. In [7], two phase retrieval methods, namely the adjoint field method and the phase angle gradient method are compared. Both these methods retrieve the phase information using the near-field amplitudes on three parallel measurement planes at different heights from the device.…”

Comparison of holographic and iterative methods for amplitude object reconstruction

“…Порой не всегда легко разо-браться, каким методом и при каких условиях лучше воспользоваться, поэтому в последнее время все чаще стали появляться работы, посвященные сравнению существующих методов восстановления волнового фронта [9][10][11][12][13][14]. Например, работы [9,10] посвящены сравнению методов, основанных на использовании априорной информации о фазе объекта, а работа [11] рассматривает методы, применимые в электромагнитной дозиметрии. В [12] производится сравнение методов цифровой голографии, использующих Фурье-фильтрацию, с новым, предложенным авторами настоящей работы методом, основанным на концепции пространственных фазовых шагов.…”