Reflector and Reflectarray Architectures with Parabolic Cylinder Optics and Phased Array Feeds

For long range radar sensors and communication links (e.g. satellite links), large antenna gains are required and many legacy systems use high gain reflectors with beams that are mechanically steered. However, mechanical scanning has inherent limitations and is insufficient for some radar and communication applications. Direct Radiating phased Arrays (DRAs) can provide electronic scanning and/or multiple beams over a wide field of view (FOV) along 2 axes (i.e. azimuth and elevation). However, large DRAs are more complex and expensive than reflector antennas. Phased Array Fed Reflectors (PAFRs) offer intermediate performance by utilizing smaller (feed) arrays to provide electronic scanning over a limited FOV. One particular PAFR architecture, the line array fed parabolic cylinder (line fed PAFR), can provide extensive electronic scanning on one axis (up to approximately ±60 degrees) and limited electronic scanning (up to approximately ±10 degrees). The large single axis scan capability of this PAFR architecture is particularly useful for some applications. In this paper, we review, compare and contrast various PAFR architectures that are relevant to both terrestrial and space-based radar and communication applications. We then compare the RF performance of these architectures and describe key hardware design and implementation trades. We also describe Phased Array Fed Reflectarray (PAFRA) based architectures with parabolic cylinder based optics realized using planar reflectarrays. Finally, we describe a few notional PAFR and PAFRA architectures that are applicable for radar and communication applications.