Feeding point determination for PIFA type mobile phone handset internal antenna

The paper presents a method for determining the best feeding point in the design of the internal antenna of a mobile phone handset. The use of an internal antenna, called intenna, has been increasing rapidly for recent state-of-the-art handsets. The main reasons for increasing intenna usage are not only new design concepts, but also because they have an excellent radiation performance compared with conventional helical stubby external antennas. There are several design parameters for PIFA type intennas, such as PIFA dimension, slit configuration, supporting carrier material and shape. Our study shows that the feeding point is also an important parameter, and bad feeding points can cause 2 to 10 dB gain reduction. The Ansoft HFSS simulation tool and Samsung SGH-X200, SGH-E800 and SGH-X650 GSM/DCS handset models are used for theoretical simulation and practical measurements.