A closed-loop regulated voltage UHF RF energy harvesting system for ultra-low voltage applications

• Ano de defesa: 2024
• Autor(a) principal: Oliveira, Tailize Cordeiro de
• Orientador(a): Severo, Lucas Compassi
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal do Pampa
• Programa de Pós-Graduação: Mestrado Acadêmico em Engenharia Elétrica
• Departamento: Campus Alegrete
• País: Brasil
• Palavras-chave em Português: Engenharia elétrica; Radiofrequência; Semicondutores complementares de óxido metálico; Radio frequency; Electrical engineering; Metal oxide semiconductors, Complementary
• Área do conhecimento CNPq: CNPQ::ENGENHARIAS
• Link de acesso: https://repositorio.unipampa.edu.br/jspui/handle/riu/9474

Harvesting the energy available in the environment is a promising strategy for powering ultra-low voltage (ULV) devices and replacing the batteries. Replacing the batteries in these devices is a complex task, making it necessary to use alternative energy sources. Among the energy sources available in the environment, RF signals stand out because they have a lower power density range and are suitable for powering ultra-low power devices. However, the RF power that is collected by the receiving antenna is not constant, and as the electronic devices need a constant supply voltage, a system capable of collecting the RF signal and converting it into a stable and regulated DC output voltage is demanded. Thus, in this dissertation, a complete RF energy harvesting (RF-EH) system that provides a stable DC supply voltage of 0.4 V is proposed to power devices in ultra-low power and ultra-low voltage applications. A closed-loop self-starting impedance tuning system, based on shunt transistors, is proposed and adopted to automatically regulate the DC output voltage of the RF-EH system. The proposed system is implemented at the schematic and layout levels in a 65 nm low-voltage CMOS process. The power conversion efficiency (PCE) of the closed-loop RF-EH, considering the post-layout result, is 50% at an input power level of -15 dBm, and frequency of 915 MHz, when generating 0.4 V of output voltage for a 10 kΩ load. The proposed solution is implemented on a chip with an effective area of 0.045 μm2 and demonstrated to power ultra-low voltage batteryless devices with a regulated output voltage of 0.4 V and output power levels of dozens μW range. Keywords: Energy harvesting, radio frequency, CMOS process, batteryless.