| 摘要 |
A microwave device (10; 100) for the ablation of biological tissues comprising a coaxial antenna (11), said coaxial antenna (1 1) comprising an internal conductor (13), surrounded by a layer of dielectric material, a external conductor (12) that is externally coaxial to said layer of dielectric material, a metal tip for penetrating tissues (14) that is connected electrically to said internal conductor (13), a quarter wave impedance transformer (16; 116) ending in a short circuit; the impedance transformer (16; 116) comprises a sleeve (15; 115) made of dielectric material having a proximal end covered with a layer of metal material (16a; 116a) obtained by depositing said metal material on the surface of said dielectric material, said layer of metal material extending over a length near a quarter of wavelength of the electromagnetic field in the dielectric material at the operating frequency of the device (10; 100) or of odd multiples of said quarter of wavelength, said layer of metal material being connected electrically to said external conductor (12); the microwave device (10; 100) further comprises a metal cannula (19) inserted above said sleeve (15; 115), said metal cannula being connected to said layer of metal material (16a; 116a) by gluing, brazing, welding or mechanical interference. |
