Demonstrates sidelobe suppression in a dish antenna using LSQR with antisymmetric dipole constraint.

This script calculates the radiation pattern of a parabolic dish and uses a ring of symmetrically placed dipoles to reduce sidelobe levels through a constrained LSQR solution. The constraint enforces antisymmetry across each ring by coupling dipoles in opposite directions with equal and opposite currents.

Inputs

• Parabolic dish geometry (focal length f, diameter d, curvature R)
• Excitation parameters (feed power E0, frequency freq, aperture radius a)
• Dipole configuration (number N, radius rho_loc, directional constraint)
• Field sampling resolution (theta_res, rho_res, etc.)
• Main lobe window extraction based on beamwidth troughs

Outputs

• Optimized dipole currents with antisymmetric constraint
• Modified far-field pattern after dipole superposition
• Plots of radiation pattern before and after dipole optimization

Notes

• The matrix T enforces antisymmetry by pairing opposite dipoles with a positive and negative sign
• Target region is outside the 3dB beamwidth, defined via rectwin
• Uses lsqr to solve the reduced system for current weights under antisymmetry