Luo Wen-bo, Wu Duo-long, Wu Yan-jie, et al. Design of a Low-profile Quad-Band PIFA Antenna for Mobile Phones[J]. 2013, 30(4): 103-106.DOI: 10.3969/j.issn.1007-7162.2013.04.019.
It presents the design of a low-profile quad-band PIFA antenna for mobile phones. The Antenna has multiband characteristics via the use of two slot and parasitic load. To enhance antenna radiation
three technologies were applied
such as digging out the ground under the feed
joining directly up ground-feed and the ground
and using passive π matching network. Experimental results show that the antenna has very good radiation performance in GSM900/DCS/PCS/UMTS operating bands
the efficiency of which is 38%、40%、42% and 39% respectively.