Low-Profile Repeater Antenna with Parasitic Elements for On-On-Off WBAN Applications

Abstract

A low-profile repeater antenna with parasitic elements for on-on-off WBAN applications is proposed. The proposed antenna consists of a planar inverted-F antenna (PIFA), two parasitic elements, and a ground plane with a slot. Due to the slot, the impedance matching of the resonance formed by the PIFA is improved, which makes the proposed antenna operate in the 5.8 GHz industrial, scientific, and medical (ISM) band. To cover the 5.2 GHz wireless local area network (WLAN) band, a dual resonance characteristic is realized by the slot and the two parasitic elements. The first coupling between the PIFA and the slot not only makes the slot operate as a resonator, but also forms secondary coupling between the slot and the two parasitic elements. The two parasitic elements operate as an additional resonator due to secondary coupling. The antenna has the enhanced near surface radiation in the 5.8 GHz ISM band due to addition of the slot and radiation toward off-body direction in the 5.2 GHz WLAN band. In order to evaluate antenna performance considering the human body effect, the antenna characteristics on a human equivalent phantom are analyzed.