RECTENNA MODEL BASED ON MOSFETS FOR MICROWAVE ENERGY HARVESTING AT ULTRA-LOW POWER LEVELS

Abstract

For wireless and battery-free power supply of autonomous devices with low power consumption harvesting
of radio frequency energy from the environment is increasingly used: energy from cellular stations,
radio stations, microwave ovens, Wi-Fi, Bluetooth, etc. To convert the collected energy into a DC voltage,
devices consisting of an antenna, a rectifier and an impedance matching circuit of the antenna and the rectifier,
called rectennas, are used. The power density of the electromagnetic field can be very small: from hundreds
of microwatts to tens of picowatts per cm2. Therefore, the task of developing rectennas capable of operating
at ultra-low power levels is urgent. The parameters of components of the rectenna (antenna, impedance
matching circuit, rectifier) are strongly interconnected, therefore, to obtain optimal characteristics, it is
necessary to design the rectenna considering the mutual influence of all components and use appropriate
models. The paper analyzes the features of the construction and development of a rectenna model based on
MOSFETs for operation at ultra-low power levels. Expressions for estimating the output voltage of the
recntenna are obtained, considering the basic parameters of the antenna, the rectifier/voltage multiplier and
the impedance matching circuit. Calculations based on the obtained expressions and modeling are performed
for a typical 90 nm CMOS technology. The possibility of constructing rectennas based on MOSFETs at ultralow
power levels up to -50 dBm is shown. Recommendations are given on the choice of technological and
design parameters of rectennas for harvesting microwave energy.