Numerical calculation of extremely large reflector antenna using high-performance parallel MLFMA

The extremely large parabolic reflector of the 500-m aperture spherical telescope (FAST) is calculated. As the largest single dish in the world, the FAST reflector is a spherical cap with a radius of 300 m and an aperture diameter of 500 m. In order to accurately calculate the FAST antenna model, the parallel multilevel fast multipole algorithm (MLFMA) is used, in combination with the improved sparse approximate inverse (SAI) preconditioner algorithm. Fast far-field calculation method based on upward pass of the MLFMA is used to accelerate the code efficiency. Result shows the efficiency for antenna gain is improved several thousand times. To verify the calculation, simulations using commercial software ANSYS FEKO were carried out, and good agreement between calculation and simulation is obtained.