Circularly-Polarized CTS Arrays

This paper proposes a novel concept of circularly-polarized continuous transverse stub (CTS) arrays. The structure consists of long radiating slots in a ground plane, fed by over-moded parallel-plate waveguides (PPWs). Two geometrically-polarized modes are launched for achieving circular-polarization (CP). An efficient in-house tool has been developed to assess the capabilities and limitations of such antenna concept. The active reflection coefficient and axial-ratio (AR) are provided together with some design guidelines. The results obtained with our tool have been validated using a full-wave commercial simulation software. We show that the proposed antenna exhibits AR better than 3 dB over a ±45° field of view. Furthermore, the active reflection coefficient is lower than -10 dB over a 55.4% operative bandwidth. The proposed concept is appealing for Ka-band terminals for Satcom applications.