Daily Image
21-06-2007
Simulating the effective area of a LOFAR high band antenna
| Submitter: | Michel Arts |
| Description: | This picture shows the effective area (Aeff) of a 7x7 array of LOFAR high band antennas as a function of element distance (i.e. separation) and observing frequency. The sensitivity of the array is proportional to Aeff. It may be seen that, at 100 MHz, the Aeff closely matches the physical area. For 170 and 240 MHz, the Aeff decreases when the element distance is greater than some critical value. This can be explained by the emergence of 'grating' lobes in the beam pattern, which distribute the sensitivity over more than just the main lobe. The Aeff at 240 MHz remains constant for element distances greater than 1.2 meter. This indicates that the array becomes sparse, with low coupling between elements, so that they can be considered as individual elements. |
| Copyright: | ASTRON |
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