Low-SAR, Miniaturized Printed Antenna for Mobile, ISM, and WLAN Services

Recently, the mobile handsets support both the mobile and wireless LAN services. Thus, our target is to introduce a new antenna that supports both services. The antenna operates for most of the mobile applications such as the GSM 850, GSM 900, DCS 1800, PCS 1900, UMTS 2100, and most of the LTE bands, especially the low-frequency LTE 700 band. The antenna also supports the WiMAX, wireless local area network (WLAN), and the Industrial, Scientific, and Medical (ISM) bands. The antenna not only has a compact size, but also it supports a low specific absorption rate (SAR) radiation at all the operating frequencies. It consists of a monopole, a meander line, and an electromagnetic band-gap (EBG) structure. In order to cover the low frequency bands, a meander line is utilized due to its compact size, but unfortunately it is a narrowband antenna that is difficult to cover both LTE700 and GSM 900 bands. The solution stems from the use of an EBG structure that widens the band to cover the two low frequency bands and to reduce the maximum SAR. The higher frequency bands are supported by both the monopole and the meander line since they acts as traveling-wave antennas at the high frequency bands. The antenna meets three challenging parameters: the compact size, the multiband operation including the low frequency bands, and the low SAR radiation. Good agreement is found between the experimental and the simulated results.