Bandwidth Enhancement for Planar Inverted F Antenna

Planar Inverted F Antenna (PIFA) is popular and widely used in handheld wireless devices because of several significant advantages. However, PIFA also has many shortages that become big limitations for its commercial application, such as narrow bandwidth. Therefore, it is a great challenge to design a PIFA with good performance. In this paper, a conventional PIFA working on GSM dual-band system (GSM 900: 900 MHz and GSM 1800: 1800 MHz) was investigated first. Then, by adding a stub on the feed line, the narrow bandwidth problem of this PIFA was well solved. By this method, no additional cost is needed, and also it is easy to manufacture.