A truly spherical microwave ablation antenna. The antenna comprises a chamber containing a coaxial cable (2) and a water guiding pipe (6). The chamber and the water guiding pipe (6) extend forward to a front portion of the antenna. At least part of an emission window (5) of the antenna is located inside the water guiding pipe (6), so that a cooling medium can reduce the temperature of the emission window (5) region of the antenna. The water guiding pipe (6) in a microwave emission region is made of an insulating material, so that microwaves can radiate outwards. The remainder of the water guiding pipe (6) is made of a microwave shielding material. A choke ring (7) provided at a rear side of the emission region is sealingly fixed to the water guiding pipe (6), so that the choke ring (7) can block the microwaves. A gap exists between the choke ring (7) and a needle rod (1). The gap is for the return of the cooling medium. The emission window (5) of the antenna is provided inside the water guiding pipe (6) so that the cooling medium can reduce the temperature of the front portion of the antenna. The cooling of the front portion of the antenna and the inhibition of the microwaves by the choke ring ensure that the shape of a microwave ablation zone is more spherical, achieving a "truly spherical" coefficient (short diameter/long diameter) of 0.95 and providing an ablation radius of 5 cm or more.L'invention concerne une antenne d'ablation hyperfréquence véritablement sphérique. L'antenne comprend une chambre contenant un câble coaxial (2) et un tuyau de guidage d'eau (6). La chambre et le tuyau de guidage d'eau (6) s'étendent vers l'avant vers une partie avant de l'antenne. Au moins une partie d'une fenêtre d'émission (5) de l'antenne est située à l'intérieur du tuyau de guidage d'eau (6), de telle sorte qu'un milieu de refroidissement peut réduire la température de la région de fenêtre d'émission (5) de l'antenne. Le tuyau de guidage d'eau (6) dans une région d'émission
