E-shaped planar inverted-F antenna with low-absorption for triple-band operation in cellular phones

A new planar inverted-F antenna (PIFA), the E-shaped PIFA, has been studied for operation in the GSM 900 MHz, 1.8 GHz and 1.9 GHz bands. The triple-band antenna is realized by etching two narrow linear slots in the patch and using two shorting strips to improve matching. A very low frequency ratio of 1.04 is obtained. The return loss curves and radiation patterns have been measured, and the finite-difference time-domain method is used to evaluate the specific absorption rate. For validation, some measured results are compared with the simulated results, and there is good agreement. The results show that the antenna has excellent performance for triple-band application in cellular phones, featuring good impedance characteristics, a gain of above 0 dBi, approximately omnidirectional radiation, and low energy absorption in users at each frequency band.