Description: | A full-wave numerical modeling approach has been used to analyze the radiation and impedance characteristics of a 7x8x2 DIGESTIF prototype antenna array. The figure shows the far-field power patterns over the frequency band ranging from 1 GHz to 1.5 GHz for each of the tapered slot antenna (Vivaldi) elements. Note the difference between the patterns of elements in the middle, and those at the edges.
These element patterns were used to compute the aperture efficiency and spillover noise temperature contribution of the DIGESTIF system when observing at several directions within +/- 1.2 degrees FOV. The calculated efficiency and noise temperature are equal to 60-70% and 6-18K, respectively. Upon collecting all numerical results, the sensitivity of the system was calculated and found to be in very good agreement with the sensitivity measured at the telescope for the same sets of the beamformer weights.
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