A High Performance 700 GHz Feed Horn

Abstract

We present a design of a high performance horn operating at 700 GHz. The feed, which comprises three smooth-walled conical sections, is easy to machine and yet has comparable performance to a corrugated horn. The measured radiation patterns show high main beam circularity, low sidelobe level and good agreement with theoretical predictions. The cross-polar level is below −20 dB across a frequency bandwidth of 140 GHz. The new design allows the fabrication of high performance, large format feed arrays cheaply and rapidly.

Smooth walled feed horns for mm and submm radio astronomy

“…We have used a machine tool whose cutting edge is made with the required shape of the interior horn profile (Fig. 2) to fabricate horns at 230 and 700 GHz[5] [6]. We have measured the beam patterns of these horns and found a good match with the theoretical expectations calculated via modal matching (Fig.…”

The Next Generation BLAST Experiment

“…However, these were not optimized for polarimetry and have a divergence in the E and H fields that results in an asymmetry between the polarization directions. BLAST-TNG will use a modified Potter horn design [Potter, 1963] with three steps, which excites additional modes in the EM field and reduces asymmetries in the polarized light, while maintaining the 30% fractional bandwidth required [Tan et al, 2012]. They also have the advantage of being much easier to fabricate than equivalent corrugated feedhorn designs.…”

A Compact Filter-Bank Waveguide Spectrometer for Millimeter Wavelengths

“…1, which shows a drawing of the five-channel prototype filter bank we have fabricated and tested. A direct-drilled circular feed horn [11] followed by a circular to rectangular transition (not shown) couples light from the sky onto the main rectangular waveguide. Each channel connects to the main waveguide through an E-plane tee that uses an evanescent coupling section into a half-wavelength resonating cavity.…”