the meter used for complex impedance measurements is called vector impedance meter.
it is used to measure the impedances over wide frequency rang, from 400 kHz to 110 MHz.
the sweep frequency plots i.e. magnitude and phase angle against frequency can al so be obtained by vector impedance meter.
such plots provide complete information within the frequency band of interest.
with the help of this meter, the magnitude and the phase angle of the impedance can be measured simultaneously.
the unknown impedance is simply connected across the input terminals and desired frequency can be selected from the front panel control.
then the two front panel readouts give the magnitude and the phase angle.