A Circularly Polarized Millimetre-Wave Phased Array for 5G Systems

Abstract

With the rise of 5G technology, communication systems are required to support high data rates with wide-band operational frequencies within the millimetre wave regime. Current deployed systems that operate at lower microwave frequencies are already congested. Hence, higher frequency ranges are presented as potential alternatives that can cater for the needs of the 5G evolution. One possible solution is the deployment of communication systems that operate at Ka-band, namely between 28 GHz and 40 GHz. These systems are required to feature wide-band, circularly polarized and high gain characteristics to overcome all the challenges encountered when an electromagnetic wave is propagating at Ka-band. A novel circularly polarized high gain phased antenna array is introduced in this thesis. The proposed antenna has a miniaturized structure with a folded feeding network to ensure compactness and minimize the coupling. The phased antenna array exhibits electronic beam steering across a wide-band range of frequencies within the Ka-band, and a scanning range of ±54⁰. Furthermore, the proposed phased antenna array is capable of switching between left- handed and right-handed circular polarization with an integration of an optimized phase shifters for more optimal DC power consumption, less cost, and decreased landscape. A 2x10 left-handed/right-handed circularly polarized array prototype is fabricated and tested, where measurements show robustness and consistency with the simulated ones. The dual circularly polarized array is operational between 26 GHz and 34 GHz, with a high gain of 13.5 dBic. While exhibiting circular polarization with a measured axial ratio is less than 3 dBic along the direction of maximum radiation within the frequency band between 29 GHz and 31 GHz, respectively.