• ADS
• fll
• internet of things
• lna
• mixer
• pll
• wake-up radio
• wi-fi

The number of Internet of Things is continuously growing, along with the rapid evolution of wireless communication, and a diffused adoption of Wi-Fi standard as linking method to permit high-throughput data exchange. Applications based on Wireless Sensor Networks (WSNs) are so widespread that energy efficiency has become a critical concern, especially for devices requiring long battery life and operating in environments with sporadic data transmission requirements. In response to this pressing challenge, the Wake-Up Radio (WUR) technology is a commonly adopted solution that allows devices to remain in a low-power state until they are needed, thereby significantly reducing energy consumption.
Wake-Up Radio systems introduce a secondary, low-power radio receiver that remains operational while the primary communication system is in sleep mode. This auxiliary receiver listens for a specific wake-up signal, triggering the activation of the primary system only when necessary.
This thesis explores the principles underlying Wake-Up Radio technology, its implementation, and its impact on enhancing the energy efficiency of wireless communication systems. The primary objective is to provide an understanding of the WUR and its potential for significantly enhancing low-power communication across various domains.
The study involves a design-space exploration of the analog Front-End (FE) of a WUR that will be implemented in STmicroelectrionics-P18 FDSOI technology. A description of every stage of the FE under examination is presented, including the Low Noise Amplifier (LNA), the Mixer and the Local Oscillator (LO), together with an evaluation of their main behavioral parameters. Furthermore, a brief overview of the final components of the FE, the Variable Gain Amplifier (VGA) and the Analog-to-Digital Converter (ADC), will also be provided.
A detailed analysis of integrated solutions for frequency synthesis of 802.11ba compliant WUR receivers in low-power and low-area Wi-Fi applications is carried out as possible models for the LO.
Different architectures of frequency synthesizers are proposed, based on both Phase Locked Loops (PLL) and Frequency Locked Loops (FLL), highlighting the advantages and issues of each model implemented. Subsequently, simulations permit a study in terms of both stability and noise, and a discussion in terms of area occupation and power consumption is presented. The analysis of oscillators is followed by the system-model LNA and Mixer: these devices will be simulated to underline the effects of non-linearities, noise and non-idealities that can affect them.
After the validation of these models stand-alone, a final simulation of the complete system can be done to emphasize its main parameters and the connection between those of individual models and their effects on the whole system. This final comparison enables the identification of weaknesses in the implemented architecture, thereby leading to the conclusion of the work that proposes valid alternatives and potential enhancements.
The study and simulation of the proposed Wake-up Radio are realized by creating a system model in the Advanced Design System (ADS) simulation environment. This approach enables the comparison of different architectures and the evaluation of the effects of system parameters variation, with a faster design time compared to transistor-level simulations and a higher level of details in comparison to high level tools like MATLAB/Simulink. The proposed models are based on both pre-existing components present in the ADS RF libraries and custom models created to emulate the behavior of the devices in STmicroelectrionics-P18 technology.