A Low Cross-Polarization Smooth-Walled Horn With Improved Bandwidth

Corrugated feed horns offer excellent beam symmetry, main beam efficiency, and cross-polar response over wide bandwidths, but can be challenging to fabricate. An easier-to-manufacture smooth-walled feed is explored that approximates these properties over a finite bandwidth. The design, optimization and measurement of a monotonically-profiled, smooth-walled scalar feedhorn with a diffraction-limited ~14° FWHM beam is presented. The feed was demonstrated to have low cross polarization (< -30 dB) across the frequency range 33-45 GHz (30% fractional bandwidth). A power reflection below -28 dB was measured across the band.