An overview of beam modeling techniques for future radio telescopes

The quality of the images produced by future radio telescopes will be limited by how accurately direction-dependent effects can be calibrated for [1]. This includes calibrating for the full polarization antenna pattern over a wide angular region, as polarization leakage and radio sources in the sidelobe region may become significant due to the high dynamic range specifications of these instruments. Temporal variation of the system properties dictates that the instruments are characterized at the time of an observation. In order to prevent substantial parameter drift during such a characterization and the subsequent observation, measurement of the radiation pattern on a direction-by-direction basis is not feasible, and the pattern has to be determined through a small number of measurements. This requires a compact parametrized representation of the beam pattern in which only a few unknown parameters need to be solved [2].