Built-in half size of folded dipole antenna for handsets

In conventional handset antennas, some gain degradation is often observed when the handsets is hold at a talk position. This is caused by the variation of the current on the conducting box used in the handset due to the human body effect. By using a balance-fed antenna, the current can be reduced remarkably. Previously, a folded loop antenna (FLA) was introduced and analyzed as a balance-fed antenna element (Morishita, H. et al., Proc.IEEE AP-S, vol.3, p.440-3, 2001). The trend in handsets is to reduce their size and the weight. Antennas must also be downsized while keeping performance unchanged or improved, especially as built-in antennas are desired. In order to make the FLA lower and smaller in volume, a built-in half-size folded dipole antenna (BHFDA), is considered and analyzed. The BHFDA is half the size of a standard folded dipole antenna. The bandwidth is evaluated to be approximately 16%, even though the antenna is miniaturized.