Spline-profile Horn Research Articles

Compact Dual Band Feed System for a Multifrequency Atmospheric Radar

The design, simulations and measurement results of a dual frequency feed horn operating at 35.75 GHz (Ka-band) and 94.05 GHz (W-band) are presented. The horn is designed to be used as a feed for a multifrequency atmospheric radar. The design is composed of three parts, a spline profile horn, a waveguide diplexer with Ka- and W-band ports orthogonal to each other and a Ka-band waveguide iris filter. The filter is used to achieve greater than 70 dB isolation between the Ka- and W-band ports. Directivities of 21 dB and 26 dB are achieved at Ka and W-band, respectively and a −12 dB beam width of 31 and 21 degrees has been achieved at Ka- and W-band. Measured patterns at both operating frequencies along with S-parameter measurements of the filter and the feed horn assembly are in good agreement with the simulation results.

Waveguide Manufacturing Technologies for Next-Generation Millimeter-Wave Antennas.

Some recent waveguide-based antennas are presented in this paper, designed for the next generation of communication systems operating at the millimeter-wave band. The presented prototypes have been conceived to be manufactured using different state-of-the-art techniques, involving subtractive and additive approaches. All the designs have used the latest developments in the field of manufacturing to guarantee the required accuracy for operation at millimeter-wave frequencies, where tolerances are extremely tight. Different designs will be presented, including a monopulse antenna combining a comparator network, a mode converter, and a spline profile horn; a tunable phase shifter that is integrated into an array to implement reconfigurability of the main lobe direction; and a conformal array antenna. These prototypes were manufactured by diverse approaches taking into account the waveguide configuration, combining parts with high-precision milling, electrical discharge machining, direct metal laser sintering, or stereolithography with spray metallization, showing very competitive performances at the millimeter-wave band till 40 GHz.

Construction and Measurement of a 31.3–45 GHz Optimized Spline-profile Horn with Corrugations

A corrugated spline-profile horn has been designed to meet the stringent specifications and constraints of a receiver for Band 1 (31.3–45 GHz) of the Atacama Large Millimeter Array (ALMA). Given the physical restrictions of the receiver, the horn will be located behind a focusing lens placed 191 mm over its aperture. After this first focusing stage, the horn must have a reflection coefficient less than −20 dB and the cross-polarization not exceeding the −30 dB level in the entire frequency range. The side-lobes should be less than −25 dB at all frequencies and its half power beamwidth must be approximately 24° at 31.3 GHz and 16° at 45 GHz. The horn has been constructed using the split-block technique and characterized in a near-field scanner setup. The results show an excellent performance complying with all the requirements.

Compact Efficient Feed-Horn at 30–38 GHz for a Multi-beam Radio Telescope

The requirements for a feed suitable for a radio telescope multi-beam focal plane array are considered. A smooth-walled spline-profile horn covering the 30–38 GHz frequency band to be used in a multi-beam receiving array of a radio telescope has been optimized, manufactured and tested. The achieved cross-section aperture size of the horn allows us to provide a neighboring beam spacing equal or less than 2HPBW for the RATAN-600 radio telescope. The measured sidelobe levels of the radiation pattern is less than −30dB/−24dB/−26dB in H/E/450-planes, cross-polarization levels better than −20 dB, an input return loss better than −18 dB and the −3dB/−10dB-beamwidths are of the order of 40o/ 80o over the frequency band. Mutual-coupling of adjacent horns is less than −38 dB.

Spline-Profile Smooth-Walled C-Band Horn

A smooth-walled spline-profile horn is optimized to cover the extended C-band satellite communication frequency band. This band is usually covered by a corrugated horn but the smooth-walled design presented here offers an economical and high-performance alternative. We compare the relative behavior between a corrugated horn and a smooth-walled horn feeding an 11-m-diameter-shaped Cassegrain earth station antenna.

A Smooth-Walled Spline-Profile Horn as an Alternative to the Corrugated Horn for Wide Band Millimeter-Wave Applications

At millimeter-wave frequencies, corrugated horns can be difficult and expensive to manufacture. As an alternative we present here the results of a theoretical and measurement study of a smooth-walled spline-profile horn for specific application in the 80-120 GHz band. While about 50% longer than its corrugated counterpart, the smooth-walled horn is shown to give improved performance across the band as well as being much easier to manufacture.