Differential Phase Patterns of the LOFAR LBA Array Measured In Situ

A complete electromagnetic model for an antenna array describes both the amplitude and phase of the embedded element patterns. The predicted phase response can usually be validated with an experimental setup in which the transmitting source is phase-locked with the receiving system. This is unpractical or even unfeasible in certain situations, such as in the case of a test source mounted on an Unmanned Aerial Vehicle (UAV) used for in-situ validation of low-frequency radio astronomical arrays. In this paper, we exploit the phase difference between the received signals to further validate the array EM models. We applied this method on a subarray of the Low Frequency Array (LOFAR).