Multiband printed-IFA on electromagnetic band-gap ground plane

Multi-band printed planar inverted-F antennas (PIFA) for available wireless communications are proposed in this paper. A PIFA with loaded L shaped over artificial ground plane was designed as the main antenna of a handset to cover the GSM (1800) MHz band, LTE (1900 MHz) band (1850 MHz - 1990 MHz), UMTS (2.1 GHz), Bluetooth (ISM) and WLAN. The multi-band is created by means of an electromagnetic band-gap (EBG) structure that is used as a ground plane. The EBG structure that is used here is a mushroom-like structure. An equivalent circuit model is employed to investigate the stop-band characteristic of the EBG and to introduce inductive and capacitive load under the 50 Ω transmission line to improve the antenna performance. The backward radiation ratio is also reduced due to the existence of EBG. Moreover, the number of resonant frequencies increases and the bandwidth extends more times as compared to the reference antenna with reduction in antenna size compared to the original antenna. This EBG PIFA is built on the ground plane with size of 30×40 mm², which is suitable for most of the mobile devices.