Numerical Optimization of a Fully Cross-Coupled Rectifier Circuit for Wireless Passive Ultra Low Power Sensor Nodes.

Area of Science:

• Electrical Engineering
• Microelectronics
• Wireless Power Transfer

Background:

• The Internet of Things (IoT) requires numerous interconnected devices, particularly sensors.
• Efficient energy harvesting and power management are critical for wireless passive sensor nodes.
• Rectifiers are essential components for providing operating voltage in these sensor nodes.

Purpose of the Study:

• To propose a numerical optimization scheme for designing highly energy-efficient integrated Complementary Metal-Oxide-Semiconductor (CMOS) rectifier circuits.
• To introduce a new target function, mean conversion efficiency (MCE), for optimizing rectifier performance.
• To explore trade-offs between various performance metrics to guide low-power rectifier design.

Main Methods:

• Development of a numerical optimization scheme for CMOS rectifier circuits with Self-Vth-Cancellation (SVC).
• Parameter space exploration to create a target function for enhancing rectified power.
• Introduction and definition of Mean Conversion Efficiency (MCE) as the arithmetic mean of Power Conversion Efficiency (PCE) and Voltage Conversion Efficiency (VCE).

Main Results:

• Optimization and simulation of a rectifier in a low-power 55 nm Globalfoundries (GF55LPe) process at -30 dBm input power.
• Achieved a mean Power Conversion Efficiency (PCE) of 63.33%.
• Achieved a mean Voltage Conversion Efficiency (VCE) of 63.40%.

Conclusions:

• The proposed numerical optimization scheme effectively enhances the performance of integrated CMOS rectifiers.
• Mean Conversion Efficiency (MCE) provides a more comprehensive metric for rectifier optimization compared to PCE and VCE.
• The study offers valuable insights for designing energy-efficient rectifiers for low-power wireless applications in the IoT.