Do not damage phone antenna. Change of its geometrical sizes, a bend, torsion inevitably worsens conditions of reception and the power of the transmitter inevitably increases. Use only firm, native antennas.
All these rather approximate reasonings were carried out in the assumption that in phone the classical shtyrevy antenna by length about a quarter of wavelength is used (taking into account a covering it approximately 70mm). In modern devices of the antenna try to do much well. But the antenna, the more its so-called good quality is shorter. Good quality determines the size of the reserved energy and this reserved energy is in a near field, that is near the antenna and is not radiated. Therefore to the head gets both the radiated power and reserved (or jet) energy. Due to absorption of part of the reserved energy-headed, existence of the head about the short antenna reduces its good quality a little and it is easier for transmitter to work.