Compact PIFA using capacitive coupled-fed for LTE/GSM/UMTS WWAN operation in the mobile application

A small-size printed PIFA using capacitive coupled-fed excitation to generate multiple resonant modes at lower and higher frequencies for eight-band operation covering LTE700 /GSM850/900/DCS1800/PCS1900/UMTS2100/LTE2300/2500 WWAN applied in the mobile phone is presented. The proposed PIFA consists of a main coupling strip which is linked to the short-circuit to the system ground plane of the mobile phone via a long inductive shorting strip and a feeding plate totally occupying a size of 15×45 mm² printed on one surface of the FR4 substrate having a volume of 45×115×1.6 mm³, making it promising for practical applications. The capacitive coupling feed allows the PIFA to generate two wide operating bands for covering 698-960 MHz and 1710-2690 MHz, synchronously. The measured antenna´s return loss, antenna gain and radiation efficiency are obtained in the letter, which can meet the requirements of practical mobile phones perfectly.