User Equipment antenna design for Non- Terrestrial Network communication

Abstract

Non-terrestrial networks (NTN) are emerging as an important component of future wireless communication systems, with 3GPP standardization efforts increasingly focused on enabling direct to device (D2D) connectivity for standard user equipment (UE). A key challenge in this context is the impact of different UE antenna designs on the link budget and regulatory compliance with electromagnetic field (EMF) exposure limits. This thesis addresses that challenge through a three part investigation of antenna design, EMF exposure assessment, and uplink link budget performance for NTN-capable UE. Three antenna designs were implemented and characterized at 3.5 GHz, a Bezel antenna, an inverted-F antenna (IFA), and a circularly polarized (CP) patch antenna. Key antenna parameters including peak realized gain and impedance bandwidth that were assessed and compared by simulations. EMF compliance was evaluated in terms of specific absorption rate (SAR) in accordance with IEEE/IEC standards and the impact of increasing transmit power to 26 dBm was also assessed. Uplink link budget analysis was subsequently performed for all three antennas and benchmarked against an isotropic radiator. Results indicate that the Bezel antenna provides the strongest link budget performance and all three antennas show compliance to EMF limits when power duty cycles are considered. The results collectively highlight a fundamental trade-off in NTN UE antenna design between ensuring EMF compliance and link performance, and provide quantitative data directly relevant to ongoing 3GPP standardization discussions. The findings suggest that transmit power class specifications for NTN UE cannot be decoupled from antenna design.