Low Profile Frequency Reconfigurable PIFA Antenna using Defected Ground Structure

In this paper, we design and implement a low profile frequency reconfigurable Planar Inverted-F Antenna (PIFA) for WLAN, m-WiMAX and UMTS applications. Dierent from several conventional designs, the air layer in our antenna is removed, while the radiator patches and ground plane are printed on two sides of the same substrate. This makes the antenna structure thin and lightweight. The defected ground structure (DGS) and coplanar sorting-trips are also designed for adjusting lower operating frequencies without increasing the antenna’s size. Three PIN-diodes are used in appropriate positions for accurate switches between frequency bands. Moreover, the three radiator patches’ parameters are optimally selected on all configurations using Genetic Algorithm (GA). Simulation results show that depending on the ON/OFF states of the PIN-diodes, the antenna can operate in three applicable frequency bands, i.e., 2.1 GHz, 2.4 GHz, and 3.5 GHz with the corresponding peak gains of 0.48 dBi, 3.55 dBi, and 4.33 dBi. The antenna occupies an overall size of 63.5x33.5x1.6 mm3, which can be easily fabricated and integrated into small wireless devices. Simulated and measured results are also compared to validate the correctness the antenna design