Demonstration of sidelobe suppression in a parabolic dish using multiple dipole rings via LSQR optimization.

This script simulates the radiation pattern of a parabolic reflector fed by a circular aperture. Dipoles arranged in concentric rings are introduced in front of the feed to suppress sidelobes while preserving the main lobe. The optimal dipole currents are computed using the least-squares solution of the field cancellation problem.

Inputs

• Dish geometry: focal length f, diameter d, rim radius R, and half-angle alpha
• Feed excitation: frequency freq, aperture radius a, and magnitude E0
• Dipole arrangement: num_rings × num_dipoles_per_ring, spaced in concentric rings
• Target suppression: sidelobes outside the main beam region are selected via a rectangular window

Outputs

• Superimposed radiation pattern with dipole corrections
• Plots of the dish surface current and 2D radiation pattern
• Dipole positions overlaid for visualization

Usage

• Run the script to visualize dipole-assisted sidelobe suppression
• Adjust dipole ring parameters and windowing bounds to study different suppression strategies

Note

• This script performs 2D slice analysis at a fixed azimuth angle (phi = 0)
• Antisymmetric dipole pairing (matrix T) is used to preserve the main lobe
• For a full 3D version, see the dish_w_dipole_lsqr_3d variant