A Circularly Polarized Parallel Plate Waveguide Lens-Like Multiple-Beam Linear Array Antenna for Satcom Applications

Abstract

This work presents a full metal circularly-polarized lens-like antenna for Satcom applications at Ka-band. The antenna is composed of two continuous parallel plate waveguide (PPW) quasi-optical beamformers (QOBF), feeding an array of septum polarizers to generate circular polarization. The QOBFs operate over a wide band and provide a multi-beam coverage over a large field of view in the azimuthal plane, while maintaining a relatively simple mechanical design. The array of septum polarizers is based on a stepped profile to generate circular polarization with a good polarization purity in the uplink of . The antenna is fully realized in aluminium. The antenna system provides 14 beams with alternating right/left handed circular polarization (RHCP/LHCP) with an axial ratio (AR) below 3 Db over an angular range of ±19 • in the uplink of Ka-Band. The maximum gain in the azimuthal plane at 30 GHz is about 21 dB over the whole angular range, with a scan loss lower than 1.5 dB. The antenna efficiency is better than 78% for all beams in the operative band.INDEX TERMS Beamformers, circular polarization, parallel plate waveguides, satcom applications, septum polarizer.

A low‐profile circularly polarized cavity‐based waveguide aperture antenna

“…Two parallel plates acting like a waveguide were used to feed an array of septum polarisers. 12 Two stubs employed at the open-end of the waveguide were very effective in adjusting the phase and amplitude of the orthogonal fields. 13 A pair of strip-shaped patches were etched on the top surface of the substrate integrated waveguide (SIW) cavity to adjust the phases of TM 211 and TM 121 modes and achieve CP to the antenna array.…”

“…However, such a ridged structure increases the volume and complexity of the design. Two parallel plates acting like a waveguide were used to feed an array of septum polarisers 12 . Two stubs employed at the open‐end of the waveguide were very effective in adjusting the phase and amplitude of the orthogonal fields 13 .…”