Spiral antennas

Full Title

Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements > Resonant antennas > with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole (H01Q9/44 takes precedence) > with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength (resonant loop antennas H01Q7/00) > Spiral antennas