stretched have a length that is about one half of the its working resonance wavelength and the resonant frequency of the outer radiator is close to that of the inner radiator either a litter higher or a litter lower than the resonant frequency of the inner radiator since uhf of the antenna is in local oscillation mode the influence on the bandwidth of uhf by antenna height is relatively strong in the invention an additional radiator structure that can generate resonance is provided at the periphery of the inner radiator of dual frequency helical to generate an additional resonant frequency close to the local oscillation frequency of uhf so that the additional resonant frequency is added to or coupled with the local oscillation frequency of uhf so as to expand uhf frequency band without having an influence on performance of gps the dual frequency antenna according to the invention mainly operates at a radio frequency an ultra high frequency uhf at about 300 800 mhz and gps frequency band in the invention the gps resonant portion is placed at the top of the antenna so that gps frequency band can form an omnidirectional pattern and more performances of the antenna.