The invention discloses a subminiature ultra-wide-band 
helical antenna which is applied to the technical field of communication. The subminiature ultra-wide-band 
helical antenna mainly comprises a radiator, a 
metal cavity, a feed 
Balun, a feed connector and wave absorbing materials. The radiator comprises plane 
helical lines, longitudinal helical lines and a medium support. The subminiature ultra-wide-band 
helical antenna enables the plane helical lines and the longitudinal helical lines to be combined together through the medium support which is sealed at one end and is the shape of a 
hollow cylinder, so that the 
band width of the antenna is increased, and meanwhile 
miniaturization of the antenna is realized. The longitudinal helical lines are connected with the antenna 
metal cavity through a 
resistor at the head ends of the longitudinal helical lines and a 
resistor at the 
tail ends of the longitudinal helical lines, so that low-frequency standing 
waves of the antenna and a directional diagram of the antenna are improved; the wave absorbing materials are arranged inside the 
metal cavity in a filling mode, so that the directional diagram, within the 
frequency band of the antenna and the 
circular polarization performance, within the 
frequency band, of the antenna are improved; due to the fact that an antenna cover is added, the use stability of the antenna is improved, and the service life of the antenna is prolonged. The subminiature ultra-wide-band 
helical antenna has the advantages of being ultra-wide in band, circularly polarized, wide in lobe, miniaturized and the like, and has broad application prospects.