Multi-band loaded inverted F antennas suitable for application in a portable device as an internal antenna having high gain property for mobile WiMAX, Wi-Fi operations , Bluetooth and WLAN are presented. The numerical simulation is carried out using the digital electromagnetic code (NEC-2) method of moments. The proposed dual inverted F antenna is suitable for 3.5/5 GHz operations and the compact triple band inverted F antenna is for 2.4/3.5/5.2 GHz operations. The total areas occupied by the antennas are 24 mm × 37 mm and 29 mm × 37 mm in case of double IFA and triple IFA, respectively. The antennas contain an incredibly high peak gain of 7.72 dBi on the 5 GHz band and gain variations in all frequency bands are less than 1 dBi. In addition, the antennas have satisfactory radiation characteristics in all frequency bands. Due to the compact area occupied, the proposed antennas promise to be integrated into the various portable devices.KEYWORDSInverted F Antenna, WiMAX, Wi-Fi, WLAN, Bluetooth1. INTRODUCTIONWireless communications have developed widely and rapidly in the modern world, especially in the last decade. In the near future, the development of personal communication devices will aim to provide image, DMB (Digital Multimedia Broadcasting) video telephony, speech and data communications anytime and anywhere in the world using WLANs ( Wireless Location Area Networks). Rapid advancements in various WLAN protocols have prompted the need for miniaturized multiband antennas with frequency bands suitable for Wi-Fi (IEEE 802.11 standard) and mobile WiMAX (IEEE 802.16e-2005 standard) applications. Bluetooth and WLAN operate in the 2.4 GHz industrial, scientific and medical (ISM) band (random frequency...... middle of paper ......Compact loop-type antenna for Bluetooth, S-DMB, Wibro, WiMax and WLAN applications." IEEE Antennas and Wireless Propagation Letters, Vol. 6, February 2007. [9] Compact Monopole Antenna for Dual-Band ISM Operation (2.4 and 5.8 GHz). . Vol.51. September 2009.[10] Kwok L. Chung, TH Mak and WY Tam. 2009.[11] GJ Burke and AJ Poggio. “Investigation of Inverted-F Planar Antennas for Wireless Communication Applications.” october. 2000