Multibeam reflectarray for transmit satellite antennas in Ka band using beam-squint

Abstract

This contribution describes a design concept based on beam squint effect in printed reflectarrays that allows to produce multiple contiguous beams at 19.5 and 20 GHz, by discriminating in frequency. A 1.6-m reflectarray has been proposed to produce 10 beams separated 0.5 degree using five feeds with frequency reuse. The simulated radiation patterns show a peak gain better than 47.6 dBi, with side-lobe levels close to -22 dB. The proposed concept can be suitable for multiple spot beam satellites in Ka-band.

Dual Polarized Reflectarray Transmit Antenna for Operation in Ku- and Ka-Bands With Independent Feeds

“…This concept can be applied to design a satellite transmit reflectarray antenna, which is optimized to fulfill the requirements for two simultaneous missions in Ku-and Ka-bands, considering different feed chains for each mission. For example, a contoured beam can be generated in Ku-band by optimizing the dipole lengths in the lower layer as in [11], and at the same time, multiple spots can be obtained in Ka-band by optimizing the dipoles on the upper layer [14], having more room to properly accommodate the feed chains of each mission. These applications will require a large reflectarray antenna (around 1.5 m diameter).…”

New advances on multi-frequency and multi-beam reflectarrays with application to satellite antennas in Ka-band

“…Furthermore, the capability of reflectarrays to implement independent phase-shifts in each polarization [8], [9], or at different frequencies [10], [11], makes it possible that a single aperture can generate independent beams in different frequencies and/or polarizations, when the antenna is illuminated by a single feed. This can be applied to the design of multi-beam antennas, where the reflectarray is used to generate multiple spot beams with a cluster of feeds placed near to the focal area of the antenna [12], [13]. In addition, the reflectarrays' low profile allows for a more efficient packaging and an easier deployment on the satellite.…”

“…Reflectarrays can be designed to generate multiple beams, either with a single feed [73]- [76], or with one or more feeds per beam [12], [13], [17], [77]- [78]. In the first case, the simplest approach consists on dividing the reflectarray surface into N subarrays, so that each sub-array will radiate a beam in a different direction [73].…”

“…When the reflectarray is illuminated by a cluster of feeds placed near to the primary feed, the antenna produces additional beams in different directions. If the reflectarray is able to discriminate in frequency or polarization, each feed can generate more than one beam [13], [59]. A reflectarray breadboard providing three simultaneous shaped beams in Ka-band (25.5 GHz) in a SFPB basis has been reported in [77], with application to base station sectored antennas for point-to-multipoint communications.…”

“…A reflectarray breadboard providing three simultaneous shaped beams in Ka-band (25.5 GHz) in a SFPB basis has been reported in [77], with application to base station sectored antennas for point-to-multipoint communications. In [13], a study on the capability of reflectarrays to generate adjacent beams in Ka-band has been performed, using beam squint effect to point the beams in different directions at two closely spaced frequencies, with the drawback of very narrow bandwidth.…”