Phase retrieval from impedance amplitude measurement

In this letter, we propose a numerical method for computing the phase spectrum of impedance. The developed method is based on the maximum entropy model (MEM) and enables one to retrieve the phase spectrum directly from an impedance amplitude spectrum. The validity of the method is tested with an input impedance measurement of a distribution transformer in the frequency band 100 kHz-30 MHz, where both the amplitude and the phase spectrum of the impedance are measured. According to the tests carried out, the method is useful and it may be applied, for example, in the research of active filters, power line communication, and electromagnetic interference.