Design and performance analysis of millimetre-wave Rotman lens-based array beamforming networks for large-scale antenna subsystems

Abstract

This paper presents the comprehensive analytical design and numerical performance evaluation of novel millimetre-wave (mm-wave) switched-beam networks, based on the Rotman lens (RL) array feeding concept. These passive array devices have been designed for operation in the 28-GHz frequency band, covering the whole 18–38 GHz frequency range. The primary objective of the work is to conduct a thorough feasibility study of designing wideband mm-wave beamformers based on liquid-crystal polymer (LCP) substrates, to be potentially employed as low-cost and high-performance subsystems for the advanced transceiver units and large-scale antennas. The presented RLs exhibit significant output behaviours for electronic beam steering, in terms of the scattering (S) parameters, phase characteristics, and surface current distributions, as the feeding systems’ primary functionality indicators.