ANTENNA ARRAY OF COMPACT VIVALDI RADIATORS WITH ELLIPTICALL SHAPE CUTOUTS ON THEIR OUTER EDGE

For wireless and battery-free power supply of autonomous devices with low power consumption harvestingof 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 hundredsof microwatts to tens of picowatts per cm2. Therefore, the task of developing rectennas capable of operatingat ultra-low power levels is urgent. The parameters of components of the rectenna (antenna, impedancematching circuit, rectifier) are strongly interconnected, therefore, to obtain optimal characteristics, it isnecessary to design the rectenna considering the mutual influence of all components and use appropriatemodels. The paper analyzes the features of the construction and development of a rectenna model based onMOSFETs for operation at ultra-low power levels. Expressions for estimating the output voltage of therecntenna are obtained, considering the basic parameters of the antenna, the rectifier/voltage multiplier andthe impedance matching circuit. Calculations based on the obtained expressions and modeling are performedfor a typical 90 nm CMOS technology. The possibility of constructing rectennas based on MOSFETs at ultralowpower levels up to -50 dBm is shown. Recommendations are given on the choice of technological anddesign parameters of rectennas for harvesting microwave energy.