Triple-band planar inverted F antenna

We present novel designs for a 3 band planar inverted F antenna (PIFA) operating at 0.9 GHz (GSM), 1.89 GHz (DECT), and 2.44 GHz (WLAN). These bands are selected for the emerging radio on fibre systems such as the passive picocell system, and could also be used for providing connectivity to the fast growing personal digital assistance (PDA) users to wireless telephony and wireless local area network services. The first design is realised with a simple inverted F design using 3 feeds. An isolation of at least 14 dB between the feed ports is achieved. The second design, a dual feed 3 band PIFA, is achieved by first embedding an L shape spur line as a reactive load on one of its radiators resulting in a dual band single feed configuration. The third band is introduced by an addition of another L-shaped inverted F antenna. Isolation of at least 18 dB is achieved between the feed ports. Bandwidth and gain of the 3 band antenna on 2 different conductive box housing are presented. A 3 band single feed PIFA using an additional L-shape spur line was also realised.