“…Various types of slot antennas with wideband or multi-band performances have been developed using tuning techniques (Behdad and Sarabandi 2004;Chang, Liu, and Liu 2005;Yao, Zhong, Wang, and Liang 2005) or varying slot shapes (Liu, Lan, Xue, and Chan 2004;Schantz 2005;Jan and Hsiang 2006;Lin and Huang 2006;Jan and Kao 2007;Lui, Cheng, and Zhu 2007;Yoon et al 2007;Qing and Chen 2009). As the demands for higher data rates and better system performances for wireless services increase, more advanced techniques are needed in future.…”