Design considerations of printed electrically small antennas

This paper discussed the Q factor comparison of several printed resonant monopole and dipole antennas at 2.4 GHz ISM band. It was found that the monopole length is not essential to the Q factor (or bandwidth) if the backside ground plane is design careful to contribute significant radiation. In contrast, for dipole antennas without ground backing, the smaller resonant antenna corresponds to larger Q factor. It was found that 50% size reduction using meander line corresponds to 3 times increase of the Q factor. It was also found that a dielectric loading will reduce antenna resonant length and decrease the Q factor. Larger dielectric constant will be preferred if the loss and resistant level is satisfactory. The relationship between planar antenna area and bandwidth is characterized.