Frequency reconfigurable dual band PIFA antenna for IoT and NB-IoT applications

A frequency reconfigurable dual band Planar Inverted-F Antenna (PIFA) dedicated to operate in industrial environments is proposed for Internet of Thing (IoT) and Narrow-Band (NB)-IoT applications. The proposed dual-band structure comprises an active element and a parasitic element. These two elements cover initially (698-708 MHz) and (878-888 MHz), respectively. The insertion of two varactors diodes MA4ST405-287 T (one in each element), which offer a capacitance range from 3.11 pF to 69.45 pF, allows their frequency reconfiguration to cover the IoT and NB-IoT bands B28 (703-803 MHz), B20 (791-862 MHz) and B8 (880-960 MHz).