Time Domain Characterization of Circularly Polarized Ultrawideband Array

The transmitted signal by a circularly polarized ultrawideband (CP-UWB) array is a short pulse of circularly rotating E-field vector in time domain. A mathematical model is derived for a transmitted pulse radiated by a CP-UWB array antenna. To validate the model, an array of four sequentially rotated ridged horns is constructed, and the transmitted pulse is measured in time domain. The measurement is done with a linearly polarized antenna in far-field, for different rotational angles. The E-field vector transmitted by the CP-UWB array is constructed with the measured time-domain pulses. The measured pulse is compared with the derived pulse for validation. Both measured and derived pulses are compared for various parameters such as the CP-UWB array´s sense of polarization, axial ratio, gain and phase difference between orthogonal signals.