Tri-Band Antenna for Energizing IoT Low Power Devices

Compact three resonant frequencies coplanar waveguide fed planar inverted-F antenna (PIFA) is introduced for the radio frequency energy harvesting. The compact CPW-fed PIFA (CPIFA) antenna is designed to collect the RF energy at three different frequency bands of GSM 900, GSM 1800 and Wi-Fi 2400. A voltage doubler circuit is designed in order to rectify the received RF power. The circuit is designed using both HSMS 2850 and HSMS 2860 Schottky diodes. A comparison between using both diodes according to the rectifier output voltage and efficiency was done. Also, a matching circuit with single stub is inserted between the antenna and voltage doubler. The aim of designing matching circuit is to match the proposed antenna with rectifier in order to get maximum power transfer and minimum loss. The rectifier circuit is fabricated and measured. The output volt is 624 mV at 0 dBm input power.