A broadband loop antenna for ultra-wideband radio

In recent years, radio communication using ultra-wideband (UWB) technology has shown great promise for healthcare and medical applications. Antennas for UWB communication, using a frequency band from 3.1 to 10.6 GHz, require suitable wideband characteristics compared with antennas for conventional narrow band wireless communication. Although many UWB antennas have been investigated and developed by several research institutes so far, it is difficult to find a loop type of antenna with broadband characteristics covering UWB frequency band. A loop antenna can be useful and effective component used in wristwatch and bracelet typed devices for the healthcare, because it is easy to build in the bracelet of them. Therefore, it is valuable to study and develop the loop type of the antennas for the wearable devices. In this paper, a loop type of the UWB antenna was proposed and investigated. The Finite Difference Time Domain method was used for the electromagnetic analyses of the antenna characteristics. As a result, the VSWR characteristics of the proposed antenna were less than 2.0 over the UWB frequency band enough in practical use.