A BROADBAND PIFA WITH ZEROTH-ORDER RESONATOR LOADING

A printed broadband planar inverted-F antenna (PIFA) with zeroth-order resonator (ZOR) loaded is proposed, whose shorting strip of the PIFA is replaced by an interdigital capacitor and thin inductive strip in series. The loaded interdigital capacitor and thin inductive strip act as a shorting strip at the 3.1 GHz, which allows the antenna to maintain its regular performance. Around 2.0 GHz, the antenna with the interdigital capacitor and thin inductive strip works on the zeroth-order resonance mode, which makes the physical size be independent of the wavelength. By merging the two modes, a broadband performance can be achieved. The size of the antenna is only 12.5 mm x 7.81 mm x 1.6 mm with single layer. The measured antenna bandwidth is 1.63 GHz (about 65%), total gain is above 2.5 dBi and the simulated radiation efficiency is over 90% in the working band. Especially the antenna has same direction of the radiation patterns in the broadband. In the end, the antenna with lumped elements loading is also discussed.