A planar inverted-f antenna (PIFA) loaded with slot for RF energy harvesting application

A Planar inverted-F Antenna (PIFA) with minimum height and enhanced gain is designed for RF energy harvesting applications. The proposed PIFA operates in the frequency range from 920 to 960 MHz with S11<-10 dB bandwidth of 40MHz. The antenna is designed with a copper sheet of thickness 0.1 mm and is placed at a height of 6.9 mm from the ground plane. Air medium and FR4 epoxy material are used as dielectric substrate. In order to miniaturize the size of PIFA, a rectangular slot of size 2×2 mm² is etched in the radiating patch. In the proposed design, this feature is made unique from the similar type of antenna reported in the literature. The introduced rectangular slot not only provides miniaturization but also removes the requirement of an external impedance matching circuit. A ground plane via shorting pin at the height of 6.9 mm from the radiating patch is included in the design to enhance the gain of the PIFA antenna. The measured results show that the proposed PIFA yields a return loss of-12 dB at the resonating frequency of 947 MHz, with measured realized gain and total efficiency of about 2.71 dBi and 87.5% respectively.